Automation of wastewater treatment processes. Automation of the technological process of collecting wastewater treatment. In this paper, the issue of automation of the technological process of collecting wastewater treatment was considered.
To effectively control the process of wastewater treatment of industrial enterprises from phenolic compounds (using Bisphenol-A as an example) using advanced oxidative processes (UV radiation, λ \u003d 365 nm, Н2О2, FeCl3), an exponential model for reducing the concentration of phenolic compounds identified in the Statistica software environment is proposed . In order to stabilize the unstable parameters of the model, the idea of \u200b\u200bregularizing A.N. Tikhonov, carried out the "ridge regression" procedure. The obtained regularized model, which establishes the dependence of the degree of decomposition of phenolic compounds in the aquatic environment under the influence of physicochemical factors (photo-Fenton reagent) on the process parameters, is statistically significant (R2 \u003d 0.9995) and has improved predictive properties than the model identified by least squares method. Using the regularized model of reducing the concentration of phenolic compounds by the method of Lagrange multipliers in the MathCad system, we determined the specific optimal consumption levels of FeCl3, H2O2, which ensure a decrease in the concentration of phenolic compounds in wastewater to the maximum permissible level.
regularization
incorrect tasks
modeling
wastewater
advanced oxidative processes
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Wastewater from a number of industries (chemical, pharmaceutical, metallurgical, pulp and paper, mining, etc.) make a significant contribution to the pollution of surface and groundwater bodies with phenolic and hardly oxidizable organic compounds. Phenol is a potentially dangerous, carcinogenic substance that presents a significant medical problem, even at low concentrations.
Advanced oxidative processes (AOPs) play an important role in the decomposition of organic substances in wastewater over a wide range of concentrations. AOP processes generate hydroxyl radicals, which are strong oxidizing agents capable of mineralizing a wide range of organic substances. The hydroxyl radical has a high redox potential (E0 \u003d 2.80 V) and is able to react with virtually all classes of organic compounds. Oxidizing hydroxyl radicals can be initiated by photolysis as a result of the photo-fenton process.
Wastewater treatment from phenolic compounds using advanced oxidative processes occurs mainly in photochemical reactors. Photochemical reactors are apparatuses in which photochemical reactions are carried out. But in them not only transformations take place, but also accompanying processes of mass and heat transfer and intense movement of the medium occur. The efficiency and safety of the cleaning process depends to the greatest extent on the correct choice of reactor type, its design, and operating mode.
When using photoreactors to solve various applied problems, large volumes of reagents must be exposed to effective radiation in them.
An important element of the photochemical treatment module in the general system of local treatment facilities is the dosing system of reagents, FeCl 3 catalyst and hydrogen peroxide Н 2 О 2.
For the stable functioning of the reactors and increase the efficiency of mineralization of organic compounds, it is necessary to optimize the purification process in order to determine the optimal doses of reagents introduced into the reactor. Optimization can be based on minimizing the costs required for the supply of reagents taking into account the environmental regulation of the cleaning process. An environmental regulator can be a function of the dependence of the concentration of an organic pollutant on process parameters (concentration of reagents and UV irradiation time), limited by the maximum permissible concentration of a phenolic compound. The concentration function is determined on the basis of a statistical analysis of the experimental data of the AOR process by the least square method (LSM).
Often the task of determining the parameters of the regression equation by the least squares method is incorrectly posed, and using the obtained equation to solve the optimization problem to determine the optimal doses of reagents can lead to inadequate results.
Thus, the aim of the work is to apply regularization methods to constructing a stable model of the dependence of the concentration of phenolic compounds on the parameters of the process of photochemical purification and identification of optimal levels of consumption of hydrogen peroxide and iron (III) chloride while minimizing the cost of reagents.
To construct a mathematical model of the dependence of the decrease in the concentration of phenolic compounds on the parameters of the AOR process with the combined effects of hydrogen peroxide, iron (III) chloride and ultraviolet radiation with a wavelength of 365 nm on a phenolic pollutant in an aqueous medium, in order to solve the optimization problem by identifying chemical consumption levels, experimental studies on model solutions containing phenolic compounds (bisphenol-A, BPA), using liquid and gas chromatography. During the optimal design of the experiment, the effect of UV radiation and oxidizing agents on the decomposition level of the organic pollutant was evaluated at various BPA concentrations - x1 (50 μg / l, 100 μg / l); hydrogen peroxide H 2 O 2 - x2 (100 mg / l; 200 mg / l) and an activator - iron (III) chloride FeCl 3 (1; 2 g / l) - x3. A model solution containing BPA, hydrogen peroxide and FeCl 3 was exposed to UV radiation for 2 hours (irradiation time t - x4). Samples were taken 1 and 2 hours after irradiation, and the residual concentration of BPA (y) was measured. The measurements were carried out by an LC-MS / MS liquid chromatograph. The half-lives during BPA photodegradation were determined using a GS-MS gas chromatograph.
When implementing the photo-Fenton process (Fe2 + / Н2О2 / hν) for the mineralization of organic pollutants in an acidic environment at pH \u003d 3, the Fe (OH) 2+ complex is formed:
Fe 2+ + H 2 O 2 → Fe 3+ + OH ● + OH -;
Fe 3+ + H 2 O → Fe (OH) 2+ + H +.
Under the action of UV radiation, the complex undergoes decomposition, as a result of which the OH ● radical and Fe 2+ ion are formed:
2+ + hν → Fe 2+ + OH ●.
A quantitative description of the photo-Fenton process at the macro level, in relation to the degradation of an organic pollutant in an aqueous medium, can be described by the model:
where 0 is the initial concentration of organic pollutant; 0, 0 - initial concentration of an activator containing iron (II) ions and hydrogen peroxide, respectively; k is the reaction rate constant; r is the reaction rate; α, β, γ - reaction orders for substances.
When creating a mathematical model of the dependence of the decrease in the concentration of phenolic compounds on the factors of the photochemical purification process with the participation of the “photo-Fenton” reagent, we will proceed from linear models or models that can be reduced to linear in coefficients using an appropriate transformation that can be written in general form in the following way :
where fi (x1, x2, ..., xm) are arbitrary functions of factors (regressors); β1, β2, ..., βk are the coefficients of the model; ε is the experimental error.
Based on the law of acting masses, the dependence of the concentration of phenolic compounds on process factors can be mathematically represented by the following expression:
where η is the level of residual concentration of BPA at time t, mg / l; x1 - initial concentration of BPA, mg / l; x2 is the concentration of hydrogen peroxide, mg / l; x3 is the concentration of iron (III) chloride, g / l; x4 - time of the cleaning process, h; β1, β2, β3, β4, β5 - model parameters.
The coefficients in the model (2) enter nonlinearly, but when linearized by logarithmation on a natural basis, the right and left sides of equation (2), we obtain
where in accordance with (1)
However, under such a transformation, a random perturbation (experimental error) enters the model multiplicatively and has a lognormal distribution, i.e. , and after logarithm this gives
After linearization and introduction of new variables, expression (2) takes the form
where the predictor variables X1, X2, X3, X4 and the response Y are logarithmic functions:
Y \u003d lny, X1 \u003d lnx1,
X 2 \u003d lnx 2, X 3 \u003d lnx 3, X 4 \u003d lnx 4;
b0, b1, b2, b3, b4 - model parameters.
Usually, in the data processing problems, the experimental matrix and response vector are not known exactly, i.e. with errors, and the task of determining the regression coefficients by the method of least squares is unstable to errors in the source data. With poor conditioning of the FTF information matrix (F is the regressor matrix), OLS estimates are usually unstable. To overcome the poor conditioning of the information matrix, the idea of \u200b\u200bregularization is proposed, justified in the works of A.N. Tikhonov.
With regard to solving regression problems, the idea of \u200b\u200bregularization A.N. Tikhonov interpreted by A.E. Hoerlom as a “ridge regression” procedure. When using the “ridge regression” method to stabilize OLS estimates (determined by b \u003d (FTF) -1FTY), regularization is associated with the addition of a certain positive number τ (regularization parameter) to the diagonal elements of the FTF matrix.
The choice of the regularization parameter τ Hoerl, Kennard and Beldwin proposed to implement as follows:
where m is the number of parameters (excluding the free term) in the original regression model; SSe is the residual sum of squares obtained from the original regression model without adjustment for multicollinearity; b * - column vector of regression coefficients, transformed by the formula
,
where bj is the parameter with the variable Xj in the original regression model, determined by the least-squares method; is the average value of the jth independent variable.
After choosing the value of τ, the formula for evaluating the regularized regression parameters will have the form
where I is the identity matrix; F is the matrix of regressors; Y is the vector of values \u200b\u200bof the dependent variable.
The value of the regularization parameter, determined by the formula (4), takes a value equal to τ \u003d 1,371 · 10-4.
The regularized model for reducing the concentration of phenolic compounds, built in the Statistica system taking into account formula (5), can be represented as
where C ost and C BPA - residual and initial concentration of phenolic pollutant, respectively, mg / l; - the concentration of hydrogen peroxide, mg / l; CA is the concentration of iron (III) chloride, g / l; t - time, h
The values \u200b\u200bof the determination coefficient, R 2 \u003d 0.9995, the Fisher criterion F \u003d 5348.417, exceeding the critical value (F cr (0.01; 4.11) \u003d 5.67), characterize the adequacy of the regularized model to the experimental results at the significance level α \u003d 0.1.
Determining the optimal specific values \u200b\u200bof the concentrations of chemical reagents (FeCl 3, H 2 O 2) required for water purification, when the minimum specific cost level is reached, is a non-linear (convex) programming task of the form (7-9):
(8)
where f is the financial function associated with the stock of chemical reagents f \u003d Z (c2, c3); gi is the function of reducing the concentration of phenolic compounds in the aquatic environment during the physicochemical purification process, g \u003d Cost (с1, c2, c3, t) (limitation function); x1, x2, ..., xn are the process parameters; x1 is the initial concentration of the phenolic compound, x1 \u003d c1, mg / l; x2 and x3 are the concentrations of hydrogen peroxide and iron (III) chloride, respectively, x2 \u003d c2, mg / l, x3 \u003d c3, g / l; t is the time, h; bi - maximum permissible concentration of phenolic compound (MPC), mg / L.
The function of financial resources, representing a two-nomenclature cost model associated with the stock of hydrogen peroxide and iron (III) chloride, taking into account the Wilson formula, can be represented as
(10)
where Z (c2, c3) - specific total costs associated with the stock, rub .; A - unit overhead costs of one total supply, rub .; c2 - specific consumption of hydrogen peroxide, mg / l; c3 - specific consumption of iron chloride, g / l; I1, I2 - specific tariffs for the costs of storing hydrogen peroxide and iron (III) chloride, respectively, rub .; m1, m2 - the share of the product price attributable to the costs of fulfilling one order for hydrogen peroxide and iron (III) chloride, respectively; i1, i2 - the share of the product price attributable to the cost of maintaining the stock of hydrogen peroxide and iron (III) chloride, respectively; k2, k3 - the unit purchase price of the unit of supply of hydrogen peroxide (rubles / mg) and iron (III) chloride (rubles / g), respectively.
To solve system (7) - (9), we introduce a set of variables λ1, λ2, ..., λm, called Lagrange multipliers, make up the Lagrange function:
,
partial derivatives are found and the system of n + m equations is considered
(11)
c n + m unknown x1, x2, ..., xn; λ1, λ2, ..., λm. Any solution to the system of equations (11) defines a conditionally stationary point at which the extremum of the function f (x1, x2, ..., xn) can take place. Under the Kuhn - Tucker conditions (12.1) - (12.6), the point is the saddle point of the Lagrange function, i.e. the found solution to problem (7) - (9) is optimal:
The task of identifying the optimal parameters of the process of treating industrial wastewater from phenolic compounds when reaching the minimum level of current unit costs required for water de-phenolization was solved with the following initial data: initial concentration of phenolic pollutant in wastewater 0.006 mg / l (6 MPC); the cleaning time determined by the technological process is 5 days (120 hours); the maximum permissible concentration of the pollutant is 0.001 mg / l (b \u003d 0.001); the unit purchase price of the reserve unit for hydrogen peroxide is 24.5 · 10 ‒6 rubles / mg (k2 \u003d 24.5 · 10 ‒6), for iron (III) chloride 37.5 · 10 ‒3 rubles / g (k3 \u003d 37.5 · 10 ‒3); the share of the product price attributable to the costs of maintaining the stock of hydrogen peroxide and iron chloride is 10% (i \u003d 0.1) and 12% (i \u003d 0.12), respectively; the share of the product price attributable to the costs of fulfilling the order for hydrogen peroxide and iron chloride is 5% (m1 \u003d 0.05) and 7% (m2 \u003d 0.07), respectively.
Solving problem (7) - (9) in the MathCad system, we obtain the point X * with coordinates
(c2 *, c3 *, λ *) \u003d (6.361 ∙ 103; 5.694; 1.346 · 10 4),
in which the Kuhn - Tucker conditions (12.1) - (12.6) are observed. There is a point that belongs to the region of feasible solutions where the Slater regularity condition is satisfied:
Сost (c2 °, c3 °) \u003d Сost (10 3, 1) \u003d - 7.22 · 10 -9< 0.
The shape of the conditionally stationary point was determined in accordance with the Sylvester criterion as applied to the Hessian matrix of the Lagrange function:
According to the Sylvester criterion, the matrix L is neither positively nor negatively defined (semidefinite) (Δ 1 \u003d 4.772 · 10 -8 ≥ 0; Δ 2 \u003d 6.639 · 10 -9 ≥ 0; Δ 3 \u003d ‒ 5.042 · 10 -17 ≤ 0).
From the fulfillment of the Kuhn - Tucker conditions, Slater regularity, and based on the study of the sign-definiteness of the Hessian matrix of the Lagrange function at a conditionally stationary point, it follows that the point (6.361 ∙ 10 3; 5.694; 1.346 · 10 4) is the saddle point of the Lagrange function, i.e. optimal solution to problem (7) - (9).
Thus, to reduce the level of phenols in industrial wastewater from 0.006 mg / l (6 MPC) to the maximum allowable (0.001 mg / l), specific operating costs of 1.545 rubles / liter will be required. This value of specific costs is minimal when using the optimal specific consumption levels of hydrogen peroxide 6.361 · 10 3 mg / l and iron (III) chloride 5.694 g / l during the cleaning process.
The method of Lagrange multipliers for technical and economic conditions (with 1 \u003d 0.006 mg / l; t \u003d 120 h; b \u003d 10 -3 mg / l; k 2 \u003d 24.5 · 10 -6 rubles / mg, k 3 \u003d 37 , 5 · 10 -3 rubles / g; i 1 \u003d 10%, i 2 \u003d 12%; m 1 \u003d 5%, m2 \u003d 7%) the problem of determining the optimal specific values \u200b\u200bof the ingredients used as oxidizing agents in the photocatalytic decomposition process phenolic compounds contained in industrial wastewater up to the MPC level.
The identified regularized mathematical model, which establishes the dependence of the level of decrease in the concentration of phenolic compounds in the aquatic environment on the parameters of the process of photochemical purification, has better predictive properties than the model determined by the least squares method. Using the obtained regularized mathematical model by the method of Lagrange multipliers, the problem of mathematical programming to determine the estimates of the optimal specific consumption levels of chemical reagents (FeCl 3, H 2 O 2), which are stable solutions, is solved.
The considered approach to identifying the optimal parameters of the photochemical treatment process using regularization will allow for the efficient management of wastewater treatment from phenolic compounds.
Reviewers:
A. Yashin, Doctor of Technical Sciences, Doctor of Biological Sciences, Professor, Department of General Pathology, Medical Institute, Tula State University, Tula;
Korotkova A.A., Doctor of Biological Sciences, Professor, Head of the Department of Bioecology and Tourism, Tula State Pedagogical University named after L.N. Tolstoy, Tula.
The work was received on February 16, 2015.
Bibliographic reference
Sheinkman L.E., Dergunov D.V., Savinova L.N. IDENTIFICATION OF THE PARAMETERS OF THE PHOTOCHEMICAL CLEANING OF INDUSTRIAL WASTE WATER FROM PHENOLIC POLLUTANTS USING REGULARIZATION METHODS // Fundamental research. - 2015. - No. 4. - S. 174-179;URL: http://fundamental-research.ru/ru/article/view?id\u003d37143 (accessed September 17, 2019). We bring to your attention the journals published by the Academy of Natural Sciences publishing house
The mechanical cleaning processes include filtering water through a grate, sand collection and primary sedimentation. The block diagram of the automation of mechanical wastewater treatment processes is presented in Fig. 52.
Fig. 52. ACS block diagram:
1 - distribution chamber; 2 - lattice stepped pit; 3 - horizontal sand trap; 4 - primary sump; 5 - sand bunker
To capture large mechanical impurities from wastewater, gratings are used. When automating gratings, the main task is to control the rake, crushers, conveyors and gates on the inlet channel. Water passes through a grate, on which mechanical impurities are retained, then, as garbage accumulates, a step grate is turned on and cleared of garbage. Automatic devices on the grates turn on when the difference in the levels of wastewater before and after the gratings increases. The angle of inclination of the lattice 60 about -80 about. The rake is switched off either by a contact device, which is activated when the level drops to a predetermined value, or by means of a time relay (after a certain period of time).
Further, after the detention of large mechanical impurities, the runoff is directed to sand traps, which are designed to trap sand and other mineral undissolved contaminants from wastewater. The principle of operation of the sand trap is based on the fact that, under the influence of gravity, particles whose specific gravity is greater than the specific gravity of water fall to the bottom as they move together with water.
The horizontal sand trap consists of the working part where the sedimentary stream moves, the purpose of which is to collect and store the precipitated sand until it is removed. The residence time of the liquid in the horizontal sand trap is usually 30-60 s, the estimated diameter of the sand particles is 0.2-0.25 mm, speed movement of waste water 0.1 m / s. Automatic devices in sand traps are used to remove sand when they reach the maximum level. For normal and effective operation of the sand trap, it is necessary to monitor and control the level of sediment, if it rises above the permissible value, then it will be agitated, and the water will be contaminated with previously settled substances. Also, automatic sand removal can be done at regular intervals, based on operating experience.
Then, the effluent enters the primary clarifier to trap floating and precipitated substances. Water slowly moves from the center to the periphery and merges into the peripheral trough with flooded holes. . To remove sludge from wastewater, a slowly rotating metal truss with scrapers mounted on it serves to rake the sludge to the center of the sump, from where it is periodically pumped out by a hydraulic elevator. The residence time (sedimentation) of the waste fluid takes 2 hours, the speed of the water is 7 m / s.
Automation of the process of physico-chemical wastewater treatment
In wastewater treatment systems by physicochemical methods, pressure flotation is most common. With this purification method, the wastewater is saturated with gas (air) under excessive pressure, which then quickly drops to atmospheric pressure.
In fig. 53 shows a block diagram of the ACP with stabilization of the quality of purified water by changing the flow rate of the recirculation stream, which carries a finely dispersed gas phase into the flotator.
The system consists of a flotation tank 1, a turbidimeter 2-1, measuring the concentration of suspended particles in purified water, an alarm 2-3, a flow meter 1-1, a regulator 1-2, control valves 1-3, which regulates the flow of wastewater entering the flotator , and a valve 2-2, which controls the flow rate of the circulating stream saturated with air in the pressure receiver 2.
The signal that occurs when the concentration of suspended matter in water above the set value increases at the output of the flotator is fed from the turbidimeter 2-1 to the regulator, which, through valve 2-2, increases the flow rate of the recirculation flow. A new amount of gas reduces the turbidity of the treated effluents. At the same time, with an increase in the flow rate of the recirculation flow through the flotation tank, a deviation signal appears at the output of the flowmeter 1-1, which is fed to the regulator 1-2. This regulator in 1-3 reduces the flow of wastewater into the flotator, ensuring a constant total flow through it.
Fig. 53. Scheme of the ASR process of wastewater treatment by pressure flotation
Introduction
1. The structure of automatic control systems
2. Dispatch management
3. Monitoring the operation of treatment facilities
Bibliographic list
Introduction
Automation of biological wastewater treatment - the use of technical means, economic and mathematical methods, control and management systems that partially or completely exempt a person from participation in processes occurring in sand traps, primary and secondary sumps, aeration tanks, oxfen, and other structures at the biological treatment station Wastewater.
The main goals of automation of wastewater systems and facilities are to improve the quality of wastewater and wastewater treatment (uninterrupted disposal and pumping of wastewater, quality of wastewater treatment, etc.); reduction in operating costs; improving working conditions.
The main function of biological wastewater treatment systems and facilities is to increase the reliability of the facilities by monitoring the condition of the equipment and automatically checking the accuracy of the information and the stability of the facilities. All this contributes to the automatic stabilization of the parameters of technological processes and quality indicators of wastewater treatment, prompt response to disturbing influences (change in the amount of waste water discharged, change in the quality of treated wastewater). Rapid detection contributes to the localization and elimination of accidents and failures in the operation of technological equipment. Providing storage and operational data processing and presenting them in the most informative form at all levels of management; data analysis and the development of control actions and recommendations to production personnel coordinates the management of technological processes, and automation of the preparation and processing of documents allows you to speed up the workflow. The ultimate goal of automation is to increase the efficiency of management activities.
1 Structure of automatic control systems
Inside each system there are the following structures: functional, organizational, informational, software, technical.
The basis for creating a system is a functional structure, while the remaining structures are determined by the functional structure itself.
On a functional basis, each control system is divided into three subsystems:
· Operational control and process control;
· Operational planning of technological processes;
· Calculation of technical and economic indicators, analysis and planning of the sewage system.
In addition, subsystems can be divided according to the criterion of efficiency (duration of the execution of functions) into hierarchical levels. Groups of similar functions of the same level are combined into blocks.
The functional structure of the ACS for treatment facilities is shown in Figure 1.
Fig. 1 Functional structure of the automated control system for treatment facilities
2 Dispatching
The main technological processes controlled and controlled by the dispatcher at the biological wastewater treatment plants are:
· Unloading of sand from sand traps and wet sediment from primary sedimentation tanks;
· Stabilization of the pH value of the water entering the aeration tanks, at the optimal level;
· Discharge of toxic wastewater into an emergency tank and its subsequent gradual supply to aeration tanks;
· Discharge of part of the water flow into the reservoir or pumping water out of it;
· Distribution of wastewater between parallel aeration tanks;
· The distribution of wastewater along the length of the aeration tank for the dynamic redistribution of the working volume between the oxidizer and the regenerator in order to accumulate sludge and increase the average daily quality of treated water;
· Air supply to maintain the optimal concentration of dissolved oxygen throughout the aerotank;
· Supply of return activated sludge to maintain a constant load of sludge on organic substances;
· Unloading of sludge from secondary sumps;
· Withdrawal of excess activated sludge from aeration tanks to maintain its optimal age;
· Inclusion in the operation of pumps and superchargers and their shutdown to minimize energy costs for pumping water, sludge, sludge and air.
In addition, the following signals are transmitted from controlled objects to control rooms: emergency shutdown of equipment; violation of the process; limit levels of wastewater in tanks; maximum concentration of explosive gases in industrial premises; maximum concentration of chlorine in the rooms of the chlorination room.
If possible, the rooms of control centers should be located near technological facilities (pump stations, blower stations, laboratories, etc.), since control actions are issued to various electronic and pneumatic controllers or directly to actuators. The control rooms provide auxiliary facilities (lounges, a bathroom, a pantry and a repair shop).
3 Monitoring the operation of treatment facilities
Based on the data of technological control and process control, the schedule of wastewater intake, its quality and energy consumption schedule are predicted to minimize the total cost of water treatment. Monitoring and control of these processes is carried out using a computer complex operating in the mode of either an adviser to a dispatcher or automatic control.
Qualitative process control and optimized control of it can be ensured by measuring parameters such as the degree of toxicity of wastewater for activated sludge microorganisms, the rate of biooxidation, BOD of incoming and treated water, the activity of sludge, and others that cannot be determined by direct measurement. The indicated parameters can be determined by calculation based on the measurement of the oxygen consumption rate in technological containers of small volume with a special load mode. The oxygen consumption rate is determined by the time of the decrease in the concentration of dissolved oxygen from the maximum to the minimum specified values \u200b\u200bwhen the aeration is turned off or by the decrease in the concentration of dissolved oxygen for a given time under the same conditions. The measurement is carried out in a cyclic installation consisting of a technological unit and a microprocessor controller that controls the nodes of the meter and calculates the rate of oxygen consumption. The time of one measurement cycle is 10-20 minutes depending on the speed. The technological unit can be installed on the bridge of maintenance of the aerotank or aerobic stabilizer. The design provides the meter in the open air in winter. The rate of oxygen consumption can be determined continuously in large volume reactors during fasting. supply of activated sludge, waste water and air. The system is equipped with dispensers with a flat stream with a productivity of 0.5-2 and 1 hour. Simplicity of design and high water flow rates ensure high reliability of measurement in a production environment. Meters can be used for continuous monitoring of the load on organic substances. Greater accuracy and sensitivity of measuring the rate of oxygen consumption is provided by manometric measuring systems equipped with pressurized reactors, the pressure of which is maintained by the addition of oxygen. The oxygen source is, as a rule, an electrolyzer controlled by a pulsed or continuous pressure stabilization system. The amount of oxygen supplied is a measure of its consumption rate. This type of meter is designed for laboratory research and BOD measurement systems.
The main purpose of ACS by air supply is to maintain specified concentrations of dissolved oxygen in the entire volume of the aeration tank. Stable operation of such systems can be achieved if not only an oxygen meter is used to control the signal, but also wastewater flow rate or oxygen consumption rate in the aeration tank core.
Regulation of aeration systems allows to stabilize the technological regime of cleaning and reduce the average annual energy consumption by 10-20%. The proportion of energy consumption for aeration is 30-50% of the cost of biological treatment, and the specific energy consumption for aeration varies from 0.008 to 2.3 kW’ / m.
Typical sludge control systems support the specified level of the sludge - water section. The section level photosensor is installed at the side of the sump in the stagnant zone. The quality of regulation of such systems can be improved by using an ultrasonic level switch. Higher quality of purified water can be obtained if a monitoring sludge of the sludge-water section is used for regulation.
In order to stabilize the sludge regime not only of the settling tanks, but also of the entire aeration tank system - the return sludge pumping station - secondary sump, it is necessary to maintain a given recirculation coefficient, i.e., so that the discharge rate of the sludge is proportional to the flow rate of the incoming sewage. The level of sludge standing is measured to indirectly monitor changes in the sludge index or a malfunction in the sludge flow control system.
When regulating the discharge of excess sludge, it is necessary to calculate the amount of sludge that has grown during the day to remove only the grown sludge from the system and stabilize the age of the sludge. This ensures high sludge quality and optimal biooxidation rate. Due to the lack of meters of activated sludge concentration, this problem can be solved with the help of oxygen consumption rate meters, since sludge growth rate and oxygen consumption rate are interconnected. The computing unit of the system integrates the amount of oxygen consumption and the amount of removed sludge and once a day adjusts the set flow rate of excess sludge. The system can be used both with continuous and periodic discharge of excess sludge.
In oxytenes, higher demands are placed on the quality of maintaining the oxygen regime due to the risk of intoxication of sludge at high concentrations of dissolved oxygen and a sharp decrease in the cleaning rate at low concentrations. During the operation of oxytenes, it is necessary to control both the supply of oxygen and the discharge of exhaust gases. The oxygen supply is controlled either by the pressure of the gas phase, or by the concentration of dissolved oxygen in the core. The discharge of exhaust gases is regulated either in proportion to the flow of waste water, or according to the concentration of oxygen in the treated gas.
Bibliographic list
1. Voronov Yu.V., Yakovlev S.V. Wastewater and wastewater treatment / textbook for universities: - M .: Publishing house of the Association of construction universities, 2006 - 704s.
Introduction
Theoretical part
1.1 Basics of the functioning of wastewater treatment
2 Analysis of modern wastewater treatment methods
3 Analysis of the possibility of automating wastewater treatment processes
4 Analysis of existing hardware (logic programmable PLC controllers) and software
5 Conclusions in the first chapter
2. Circuitry part
2.1 the Development of the structural diagram of the water level to fill the tank
2.2 Development of a functional diagram
3 Calculation of the regulatory body
4 Defining controller settings. Synthesis of self-propelled guns
5 Calculation of the parameters of the built-in ADC
2.6 Conclusion for the second chapter
3. The software part
3.1 Development of the algorithm for the functioning of the NAC system in the environment CoDeSys
3.2 Program Development in CoDeSys
3 Development of an interface for visual display of measurement information
4 Conclusions in the third chapter
4. Organizational and economic part
4.1 Cost-effectiveness of process control systems
2 Calculation of the main costs of the control system
3 Organization of production processes
4.4 Conclusions on the fourth section
5. Life safety and environmental protection
5.1 Life safety
2 Environmental protection
3 Conclusions in the fifth chapter
Conclusion
List of references
Introduction
At all times, human settlements and industrial facilities were located in close proximity to fresh water bodies used for drinking, hygienic, agricultural and industrial purposes. In the process of using water by humans, it changed its natural properties and, in some cases, became sanitary hazardous. Subsequently, with the development of the engineering equipment of cities and industrial facilities, there was a need for organized methods for discharging contaminated spent water flows through special hydraulic structures.
Currently, the importance of fresh water as a natural raw material is constantly increasing. When used in everyday life and industry, water is polluted by substances of mineral and organic origin. Such water is called wastewater.
Depending on the origin of wastewater, they may contain toxic substances and pathogens of various infectious diseases. The water management systems of cities and industrial enterprises are equipped with modern complexes of gravity and pressure pipelines and other special facilities that implement the diversion, treatment, neutralization and use of water and precipitation. Such complexes are called the drainage system. Drainage systems also provide drainage and treatment of rain and melt water. The construction of drainage systems was determined by the need to ensure normal living conditions of the population of cities and towns and maintain a good state of the environment.
Industrial development and urban growth in Europe in the 19th century They led to the construction of drainage canals. A strong impetus for the development of urban sanitation was the cholera epidemic in England in 18g. In subsequent years, in this country, the efforts of the parliament took measures to replace open canals with underground ones and approved the quality standards for wastewater discharged into water bodies, organized biological treatment of domestic wastewater in irrigation fields.
In 1898, the first drainage system was put into operation in Moscow, including gravity and pressure drainage networks, a pumping station and Lublin irrigation fields. She became the founder of Europe’s largest Moscow sewage and wastewater treatment system.
Of particular importance is the development of a modern sewage system for domestic and industrial wastewater, providing a high degree of protection of the natural environment from pollution. The most significant results were obtained in the development of new technological solutions for the efficient use of water from wastewater systems and wastewater treatment plants.
Prerequisites for the successful solution of these problems in the construction of drainage systems are developments carried out by highly qualified specialists using the latest achievements of science and technology in the field of construction and reconstruction of drainage networks and treatment facilities.
1. The theoretical part
1 Basics of the functioning of wastewater treatment
Wastewater - any water and precipitation discharged into reservoirs from the territories of industrial enterprises and populated areas through a sewage system or by gravity, the properties of which turned out to be deteriorated as a result of human activity.
Wastewater can be classified by source of origin into:
) Production (industrial) wastewater (generated in technological processes during the production or extraction of minerals) is discharged through a system of industrial or general alloy sewage.
) Domestic (household and fecal) wastewater (generated in residential premises, as well as in domestic premises in production, for example, showers, toilets), is discharged through a domestic or general alloy sewage system.
) Surface wastewater (divided into rainwater and melt, that is, formed when the snow, ice, hail melts) is usually discharged through a storm sewer system. Also referred to as "storm drains."
Industrial wastewater, unlike atmospheric and domestic, does not have a constant composition and can be divided by:
) The composition of the pollutants.
) Concentrations of pollutants.
) The properties of pollutants.
) Acidity.
) Toxic and pollutant effects on water bodies.
The main goal of wastewater treatment is water supply. The water supply system (of a populated place or an industrial enterprise) must ensure the receipt of water from natural sources, its treatment, if this is caused by the requirements of consumers, and supply to places of consumption.
Water supply scheme: 1 - source of water supply, 2 - water intake structure, 3 - pump station I lift, 4 - treatment facilities, 5 - clean water tank, 6 - pump station II lift, 7 - water pipes, 8 - water tower, 9 - water distribution network.
To perform these tasks, the following structures are used, which are usually part of the water supply system:
) Water intake facilities by which water is received from natural sources.
) Water-lifting structures, i.e. pumping stations, supplying water to the places of its purification, storage or consumption.
) Facilities for water treatment.
) Water conduits and water supply networks used to transport and supply water to places of consumption.
) Towers and reservoirs playing the role of regulating and spare tanks in the water supply system.
1.2 Analysis of modern methods of wastewater treatment
Modern methods of wastewater treatment can be divided into mechanical, physicochemical and biochemical. In the process of wastewater treatment, sludge is formed, which are neutralized, decontaminated, dehydrated, dried, and subsequent disposal of sludge is possible. If, according to the conditions of discharge of wastewater into a water body, a higher degree of purification is required, then after the complete biological wastewater treatment facilities, deep treatment facilities are arranged.
Mechanical wastewater treatment facilities are designed to retain undissolved impurities. These include grilles, sieves, sand traps, sumps and filters of various designs. Grids and sieves are designed to trap large contaminants of organic and mineral origin.
Sand traps are used to isolate mineral impurities, mainly sand. Sumps trap sediment and floating wastewater pollution.
For the treatment of industrial wastewater containing specific contaminants, structures called grease traps, oil traps, oil and tar traps, etc. are used.
Mechanical wastewater treatment plants are a preliminary stage before biological treatment. With mechanical treatment of urban wastewater, it is possible to retain up to 60% of undissolved pollution.
Physico-chemical methods of urban wastewater treatment, taking into account technical and economic indicators, are used very rarely. These methods are mainly used for the treatment of industrial wastewater.
The methods of physical and chemical treatment of industrial wastewater include: reagent treatment, sorption, extraction, evaporation, degassing, ion exchange, ozonation, electroflotation, chlorination, electrodialysis, etc.
Biological methods of wastewater treatment are based on the vital activity of microorganisms, which mineralize dissolved organic compounds, which are food sources for microorganisms. Biological treatment facilities can conditionally be divided into two types.
Figure 3 - Scheme of wastewater treatment on biofilters
Scheme of wastewater treatment on biofilters: 1 - grate; 2 - sand trap; 3 - pipeline for removing sand; 4 - primary sump; 5 - output of sludge; 6 - biofilter; 7 - jet sprinkler; 8 - chlorination point; 9 - secondary sump; 10 - release.
Mechanical wastewater treatment can be performed in two ways:
) The first method consists in filtering water through grates and sieves, as a result of which solid particles are separated.
) The second method consists in settling water in special settling tanks, as a result of which mineral particles settle to the bottom.
Figure 4 - Technological scheme of a treatment plant with mechanical wastewater treatment
Technological scheme: 1 - waste water; 2 - gratings; 3 - sand traps; 4 - sedimentation tanks; 5 - mixers; 6 - contact tank; 7 - issue; 8 - crushers; 9 - sand pads; 10 - digesters; 11 - chlorination; 12 - silt sites; 13 - waste; 14 - pulp; 15 - sand pulp; 16 - crude sediment; 17 - fermented sediment; 18 - drainage water; 19 - chlorine water.
Wastewater from the sewer network first goes to grates or sieves, where they are filtered, and large components - rags, kitchen waste, paper, etc. - are held. Large components detained by grids and nets are removed for disinfection. The filtered wastewater enters the sand traps, where impurities of mainly mineral origin (sand, slag, coal, ash, etc.) are retained.
1.3 analysis of the possibility of automation, wastewater treatment processes
The main goals of automating wastewater systems and facilities are to improve the quality of wastewater and wastewater treatment (the continuity of wastewater disposal and pumping, the quality of wastewater treatment, etc.), reduce operating costs, and improve working conditions.
The main function of wastewater systems and facilities is to increase the reliability of facilities by monitoring the status of equipment and automatically checking the accuracy of information and the stability of facilities. All this contributes to the automatic stabilization of the parameters of technological processes and quality indicators of wastewater treatment, prompt response to disturbing influences (change in the amount of wastewater discharged, change in the quality of treated wastewater). The ultimate goal of automation is to increase the efficiency of management activities. The treatment plant management system has the following structures: functional; organizational; informational; software; technical.
The basis for creating a system is a functional structure, while the remaining structures are determined by the functional structure itself. On a functional basis, each control system is divided into three subsystems:
operational control and process control;
operational planning of technological processes;
calculation of technical and economic indicators, analysis and planning of the sewage system.
In addition, subsystems can be divided according to the criterion of efficiency (duration of the execution of functions) into hierarchical levels. Groups of similar functions of the same level are combined into blocks.
Figure 5 - The functional structure of the ACS treatment facilities
To increase the efficiency of data transfer, communication with dispatching points and sewage management, as well as wastewater treatment processes, it is recommended to replace the not always reliable telephone communication system with fiber optic. Moreover, most of the processes in automatic control systems for drainage networks, pumping stations and wastewater treatment plants will be performed on a computer. This also applies to accounting, analysis, calculations of long-term planning and work, as well as the implementation of the necessary documents for reporting on the operation of all systems and structures of water disposal.
To ensure the smooth operation of wastewater systems based on accounting and reporting, it is possible to carry out long-term planning, which, ultimately, will increase the reliability of the entire complex.
1.4 Analysis of existing hardware (logic programmable PLC controllers) and software
Programmable logic controllers (PLCs) have been an integral part of enterprise automation systems and process control systems for decades. The range of applications that use PLCs is very wide. It can be either simple lighting control systems or environmental monitoring systems at chemical plants. The central unit of the PLC is the controller, to which the components providing the required functionality are added, and which is programmed to perform some specific task.
The controllers are manufactured by well-known electronics manufacturers, such as Siemens, Fujitsu, or Motorola, and control electronics companies, such as Texas Instruments Inc. Naturally, all controllers differ not only in functionality, but also in combination of price and quality. Since microcontrollers of the Siemens company are currently the most common in Europe, they can be found both at production facilities and at laboratory stands, then we will choose the German manufacturer.
Figure 6 - Logic module "LOGO"
Scope: management of technological equipment (pumps, fans, compressors, presses) heating and ventilation systems, conveyor systems, traffic control systems, control of switching equipment, etc.
Programming of Siemens controllers - LOGO! Basic modules can be performed from the keyboard with information displayed on the integrated display.
Table 1 Specifications
Supply voltage / input voltage: nominal value ~ 115 ... 240 V AC frequency ~ 47 ... 63 Hz Power consumption for supply voltage ~ 3.6 ... 6.0 W / ~ 230 V Discrete inputs: Number of inputs: 8 Input voltage: low level, no higher level, not less than 5 V 12 V Input current: low level, no higher level, at least ~ 0.03 mA ~ 0.08 mA / \u003d 0.12 mA Discrete outputs: Number of outputs 4 Galvanic isolation Yes Connection of a digital input as load Possible Analog inputs: Number of inputs 4 (I1 and I2, I7 and I8) Range and measurements \u003d 0 ... 10 VMaksimalnoe input voltage \u003d 28.8 VStepen protection korpusaIP 20Massa190 g
The programming process of the "Siemens" controller is reduced to the software connection of the required functions and setting the parameters (on / off delays, counter values, etc.). To perform all these operations, a built-in menu system is used. The finished program can be rewritten into a memory module enclosed in the interface of the LOGO! Module.
The microcontroller "LOGO!", A German company "Siemens", is suitable for all technical parameters.
Consider microcontrollers of domestic production. In Russia, there are currently not many enterprises that produce microcontroller technology. At the moment, a successful company specializing in the production of control automation systems is the company "OWEN", which has at its disposal production facilities in the Tula region. Since 1992, this company has specialized in the production of microcontrollers and sensor equipment.
The leader of the OVEN microcontrollers is a series of PLC logic controllers.
Figure 7 - Appearance of the PLC-150
PLC-150 can be used in various fields - from the creation of control systems for small and medium-sized objects to the construction of dispatch systems. Example Automation of a building's water supply system using an Aries PLC 150 controller and an Aries MVU 8 output module.
Figure 8 - Water supply scheme of a building using PLC 150
Consider the main technical parameters of the PLC-150. General information is given in the table.
Table 2 General Information
Design Unified housing for mounting on DIN & rail (width 35 mm), length 105 mm (6U), terminal pitch 7.5 mm Enclosure protection IP20 Supply voltage: PLC150 & 22090 ... 264 V AC (rated voltage 220 V) with a frequency of 47 ... 63 Hz Front panel display 1 indicator power supply 6 status indicators for digital inputs 4 status indicators for outputs 1 indicator for communication with CoDeSys 1 indicator for user program operation Power consumption 6 W
The resources of the logic controller PLC-150 are shown in table 3.
Table 3 Resources
Central processor 32 & x bit RISC & 200 MHz processor based on ARM9 core RAM size 8 MVO Non-volatile memory storage of the CoDeSys core programs and archives 4 MV Retain & memory size 4 kV PLC cycle time Minimum 250 μs (non-fixed), typical from 1 ms
Information on digital inputs is given in table 4.
Table 4 Digital Inputs
Number of discrete inputs6 Galvanic isolation of discrete inputs, group; Dielectric strength of isolation of discrete inputs1.5 kVMaximum frequency of a signal applied to a discrete input1 kHz with 10 kHz software processing using a hardware counter and encoder processor
Information on analog inputs is given in table 5.
Table 5 Analog Inputs
Number of analog inputs 4 Types of supported unified input signals Voltage 0 ... 1 V, 0 ... 10 V, -50 ... + 50 mV Current 0 ... 5 mA, 0 (4) ... 20 mA Resistance 0 .. .5 kOhm Types of supported sensors Thermal resistance: TSM50M, TSP50P, TSM100M, TSP100P, TSN100N, TSM500M, TSP500P, TSN500N, TSP1000P, TSN1000N Thermocouples: THK (L), TZHK (J), THA (N), THA (N), THA (N) ), TPP (R), TPR (V), TVR (A & 1), TVR (A & 2) Built-in ADC bit 16 bits Internal resistance of the analog input: in the current measurement mode in the voltage measurement mode 0 ... 10 V 50 Ohms about 10 kOh analog input 0.5 cP Yedelev basic reduced error measure analog vhodami0,5% Isolation analog vhodovotsutstvuet
PLC-150 programming is carried out using the professional programming system CoDeSys v.2.3.6.1 and later. CoDeSys is a Controller Development System. The complex consists of two main parts: the CoDeSys programming environment and the CoDeSys SP runtime system. CoDeSys runs on the computer and is used in the preparation of programs. Programs are compiled into fast machine code and loaded into the controller. CoDeSys SP works in the controller, it provides code loading and debugging, I / O servicing and other service functions. More than 250 well-known companies make equipment with CoDeSys. Every day thousands of people work with him, solving industrial automation problems. Today, CoDeSys is the most common IEC programming complex in the world. In practice, he himself serves as the standard and model for IEC programming systems.
PLC synchronization with a personal computer is performed using the "COM" port, which is on every personal computer.
The microcontroller of the company "OWEN" of domestic production is suitable for all parameters. Both analog and digital measuring devices with unified signals can be connected to it. The controller is easily compatible with a personal computer using the "COM" port, there is the possibility of remote access. PLC-150 matching with programmable logic controllers of other manufacturers is possible. PLC-150 is programmed using the Controller Development System (CoDeSys), in a high-level programming language.
5 Conclusions in the first chapter
This chapter examined the basics of the functioning of wastewater treatment, analysis of modern treatment methods and the possibility of automating these processes.
An analysis was made of existing hardware (logic programmable PLC controllers) and software for controlling process equipment during wastewater treatment. The analysis of domestic and foreign manufacturers of microcontrollers.
2. Circuitry part
One of the important automation functions is: automatic control and management of technological processes, equipment of pumping stations and treatment facilities, creation of automated workplaces for all specialties and work profiles based on modern technologies.
The main function of wastewater systems and facilities is to increase the reliability of facilities by monitoring the status of equipment and automatically checking the accuracy of information and the stability of facilities. All this contributes to the automatic stabilization of the parameters of technological processes and quality indicators of wastewater treatment, prompt response to disturbing influences (change in the amount of waste water discharged, change in the quality of treated wastewater). The ultimate goal of automation is to increase the efficiency of management activities.
Modern drainage networks and pumping stations should be developed with control whenever possible without the constant presence of maintenance personnel.
1 Development of a structural diagram of the water level to fill the main tank
The block diagram of the automatic control system is shown in Figure 9:
Figure 9 - Structural diagram
To the right of the structural diagram is the PLC-150. To the right of it is an interface for connecting to a local area network (Ethernet) to gain remote access to the controller. The signal is transmitted digitally. Through the RS-232 interface is negotiated with a personal computer. Since the controller is not demanding on the technical component of the computer, even a weak "machine" such as Pentium 4 or similar models will be enough for the entire system to work correctly. The signal between the PLC-150 and a personal computer is transmitted digitally.
2 Development of a functional diagram
The functional diagram of the automatic water level control system is shown in Figure 10:
Figure 10 Functional Diagram
Parameters of the transfer function of the control object
According to the terms of reference, we have:
H \u003d 3 [m] - pipe height.
h 0 \u003d 1,0 [m] -set level. Q n0 \u003d 12000 [l / h] -nominal expense. d \u003d 1.4 [m] -pipe diameter. OU transfer function: (1)
We calculate the numerical values \u200b\u200bof the transfer function. Tank cross-sectional area: (2)
Nominal incoming flow: (3)
Gear ratio K: (4)
Time constant T: (5)
Thus, the transfer function for the control object will look like: (6)
The structure of the automatic control system is shown in Figure 0: Figure 11 - Structural diagram of self-propelled guns Where: Cr.o.- coefficient of transfer of the regulatory body (RO) of the incoming flow Qпо; Cd - gear ratio of the level sensor h Wp - automatic regulator transfer function Calculation of the gain of the regulatory body K r.o :
,
where - change in incoming flow; change in the degree of valve opening (in percent). The dependence of the incoming flow on the degree of valve opening is shown in Figure 12: Figure 12 - Dependence of the incoming flow on the degree of valve opening Estimation of the gain of the level sensor The gain of the level sensor is defined as the ratio of the increment of the output parameter of the level sensor i [mA] to the input parameter [m]. The maximum height of the liquid level that the level sensor should measure corresponds to 1.5 meters, and a change in the current unified output signal of the level sensor when the level changes in the range 0-1.5 meters corresponds to 4-20 [mA]. (7)
General industrial level sensors have a built-in function to smooth the output signal with an inertial filter-link of the first order with a set time constant Tf in the range from units to tens of seconds. We select the filter time constant Tf \u003d 10 s. Then the transfer function of the level sensor is equal to: (8)
The structure of the control system will take the form: Figure 13 - the structure of the control system Simplified structure of the control system with numerical values: Figure 14 - a simplified structure of the control system Logarithmic amplitude-phase frequency characteristics of the unchanged part of the system The LAFCH of the unchanged part of the self-propelled guns are constructed by the approximate method, consisting in the fact that for a link with a transfer function: (9)
in a logarithmic coordinate grid up to a frequency of 1 / T, where T \u003d 56 s is the time constant, the LACH looks like a line parallel to the frequency axis at the level of 20 log K \u003d 20 log0.43 \u003d -7.3 dB, and for frequencies greater than 1 / T, LACH has the form of a straight line with a slope of -20dB / dec to the mating frequency of 1 / TF, where the slope also changes by -20dB / dec and is -40dB / dec. Interfacing frequencies: (10)
(11)
Thus we have: Figure 15 - LAPFC of the open source system 2.3 Calculation of the regulatory body for incoming and outgoing costs We make a selection of the regulatory body based on the conditional throughput Cv. Calculation of Сv value is carried out according to the international standard DIN EN 60534 according to the following formula: (12)
where Q is the flow rate [m 3/ h] ρ - fluid density [kg / m 3], Δ p is the pressure difference [bar] in front of the valve (P1) and behind the valve (P2) in the direction of flow. Then for flow regulator Q n0 according to the source data: (13)
For a possible change in the flow rate Qp in the process of automatic control relative to its nominal value Qp 0 we take the maximum value of Qp twice as much as the nominal, i.e. .
The bore diameter for the incoming flow is calculated as follows: (14)
Similarly, for outgoing flow we have: (15)
(16)
2.4 Definition of controller settings. Synthesis of self-propelled guns The construction of an open-loop self-propelled system LFVC is based on the corollary of the theory of linear systems that if the open-loop LACF (consisting of minimum phase units) has a slope of -20 dB / dec in the region of significant frequencies (sector cut off by lines of ± 20 dB, then: closed self-propelled guns are stable; the transition function of a closed self-propelled gun is close to monotonic; regulation time . (17)
The structure of the open source system with PI - controller: Figure 16 - The structure of the original system with a PI controller Desired LACH (L well ) of the simplest form of an open self-propelled guns, which in closed form would satisfy the specified quality indicators, should have in the vicinity of significant frequencies the slope of the LAHF equal to -20dB / dec and intersection with the frequency axis for: (18)
In the field of low-frequency asymptotes, to create a zero (according to TK) static error δ st \u003d 0, the frequency characteristics of an open system must correspond to an integrator of at least 1st order. Then it is natural to form the desired LAC in this area in the form of a straight line with a slope of -20 dB / dec. as a continuation of Lf from the region of essential frequencies. In order to simplify the implementation of ACS, the high-frequency asymptote should correspond to the high-frequency asymptote of the unchanged part of the system. Thus, the desired open-loop LAC is shown in Figure 0: Figure 17 - Desired open-loop VARC According to the adopted structure of industrial self-propelled guns, the only means of bringing LAFCH constant part L lF to L well is a PI regulator with the transfer function of the LAFCH (at K r =1)
Figure 18 - LAFCH PI controller Figure 14 shows that for in the low-frequency region, the LACH of the PI controller corresponds to an integrating unit with a negative phase shift of -90 degrees, and for the frequency characteristics of the controller correspond to the amplification link with a zero phase shift in the region of the essential frequencies of the designed system with the appropriate choice of the value of T and .
We take the integration constant of the controller equal to the time constant T of the control object, i.e., T and \u003d 56, at K r \u003d 1. Then the LACH of an open self-propelled gun will take the form L 1\u003d L lF + L pi qualitatively corresponding to the form L well in the figure, but with a lower gain. For coincidence LACH design system with L well it is necessary to increase the gain of an open system by 16 dB, i.e. 7 times. Therefore, the controller settings are defined. Figure 19 - Synthesis of self-propelled guns. Defining controller settings The same controller settings are obtained if from L well subtract L graphically lF and by the form of the LACH of the resulting serial corrector (PI controller), restore its transfer function. As can be seen from figure 12 at T and \u003d T \u003d 56 s, the transfer function of the open system has the form , which includes an integrating unit. When constructing the LACH corresponding to W p (p) gear ratio K p 0,32/7850 must numerically correspond to the frequency of intersection of LACH with the axis ω on frequency from -1from where from -1 or K p =6,98.
At the calculated settings of the ACS controller, it is stable, has a transition function close to monotonic, the regulation time t r \u003d 56 s, static error δ st =0.
Sensor equipment The 2TPM0 meter is designed to measure the temperature of coolants and various media in refrigeration equipment, ovens, furnaces for various purposes and other technological equipment, as well as for measuring other physical parameters (weight, pressure, humidity, etc.). Figure 20 - 2TRM0 meter Accuracy class 0.5 (thermocouples) / 0.25 (other types of signals). The regulator is available in 5 types of cases: wall-mounted, mounting on a DIN rail D and panel board Щ1, Щ11, Щ2. Figure 21 - Functional diagram of the device Aries 2 TPM 0. Figure 22 - Dimensional drawing of the measuring device Device connection diagram: The figure shows the diagram of the terminal block of the device. The figures show the connection diagrams of the device. Figure 23 - Device connection diagram The terminal block of the device. The BP14 multichannel power supply unit is designed to supply sensors with a stabilized voltage of 24 V or 36 V with a unified output current signal. The BP14 power supply is available in a housing with mounting on a DIN rail of type D4. Figure 28 - Power Supply Main functions: Conversion of alternating (constant voltage to constant stabilized in two or four independent channels; Inrush current limitation; Input surge protection; Protection against overload, short circuit and overheating; Indication of the presence of voltage at the output of each channel. Figure 29 - Connection diagram of a two-channel power supply unit BP14 The frequency of the input AC voltage is 47 ... 63 Hz. Current protection threshold (1.2 ... 1.8) Imax. The total output power of 14 watts. The number of output channels 2 or 4. The rated output voltage of the channel is 24 or 36 V. Figure 30 - Outline drawing of the power supply The instability of the output voltage when the supply voltage changes ± 0.2%. The instability of the output voltage when the load current changes from 0.1 Imax to Imax ± 0.2%. The operating temperature range is -20 ... + 50 ° C. The coefficient of temperature instability of the output voltage in the operating temperature range ± 0.025% / ° C. Dielectric strength insulation-input-output (actual value) 2 K. SAU-M6 is a functional analog of the ESP-50 and POC 301 devices. Figure 31 - Level Switch Figure 32 - Connection diagram SAU-M6 Three-channel liquid level switch Aries SAU-M6 - is designed to automate technological processes associated with the control and regulation of the liquid level. Figure 33 - Functional diagram of SAU-M6 SAU-M6 is a functional analog of the ESP-50 and POC 301 devices. The device is available in a type N wall mount housing. Level Switch Functionality Three independent channels for monitoring the liquid level in the tank The ability to invert the operation mode of any channel Connection of various level sensors - conductometric, float-operated Work with liquids of various electrical conductivity: distilled, tap, contaminated water, milk and food products (weakly acid, alkaline, etc.) Protection of conductive sensors from the deposition of salts on the electrodes by supplying them with alternating voltage Figure 34 - Dimensional drawing Technical characteristics of the device rated voltage of the device 220 V at a frequency of 50 Hz. Permissible deviations of the supply voltage from the nominal value -15 ... + 10%. Power consumption, no more than 6 VA. The number of level control channels is 3. The number of built-in output relays is 3. The maximum permissible current switched by the contacts of the built-in 4 A relay at 220 V 50 Hz (cos\u003e 0.4). Figure 35 - Discrete input / output module Discrete input and output module for distributed systems in the RS-485 network (Aries, Modbus, DCON protocols). The module can be used in conjunction with programmable controllers Aries PLC or other MDVV operating in the RS-485 network if it has a "master", while the DVMV itself is not a "master" of the network. discrete inputs for connecting contact sensors and transistor switches of n-p-n type. Ability to use any discrete input (maximum signal frequency - 1 kHz) Possibility of generating a PWM signal by any of the outputs Automatic transfer of the actuator to emergency operation in case of network interruption Support for widespread Modbus protocols (ASCII, RTU), DCON, ARIES. Figure - 36 General connection diagram of the MDVV device Figure 37 - Functional diagram of DVA MEOF are designed to move the working bodies of shut-off and control valves of the rotary operating principle (ball and plug valves, butterfly valves, butterfly valves, etc.) in automatic process control systems of various industries in accordance with command signals from control or control devices . Mechanisms are installed directly on the valve. Figure 38 - The device mechanism MEOF Figure 39 - Overall dimensions The installation diagram of the Metran 100-DG 1541 sensor when measuring hydrostatic pressure (level) in an open tank: Figure 40 - Sensor installation diagram The principle of operation of the sensors is based on the use of the piezoelectric effect in a heteroepitaxial silicon film grown on the surface of a single crystal wafer made of artificial sapphire. Figure 41 - Appearance of the device A sensitive element with a single-crystal silicon structure on sapphire is the basis of all sensor blocks of the Metran family of sensors. For a better overview of the liquid crystal indicator (LCD) and for ease of access to the two compartments of the electronic transducer, the latter can be rotated relative to the measuring unit from the set position by an angle of no more than 90 ° counterclockwise. Figure 42 - Diagram of the external electrical connection of the sensor: Where X is the terminal block or connector; Rн - load resistance or total resistance of all loads in the control system; BP - DC power source. 2.5 Calculation of the parameters of the built-in ADC We calculate the parameters of the built-in ADC of the PLC-150 microcontroller. The main parameters of the ADC should include the maximum input voltage U max , the number of bits of the code n, the resolution ∆, and the conversion error. The resolution of the ADC is determined by the formula: Log 2N, (19) where N is the number of discrete (quantum levels); Since the ADC is built into the selected PLC-150 controller, we have n \u003d 16. The resolution of the ADC is the input voltage corresponding to one in the low order of the output code: (20)
where 2 n - 1 - maximum weight of the input code, in \u003d U max - U min (21)
At U max \u003d 10V, U min \u003d 0V, n \u003d 16, (22)
The larger n, the smaller and more accurately the input voltage can be represented by the output code. Relative resolution: , (23)
where ∆ is the smallest distinguishable step of the input signal. Thus, ∆ is the smallest distinguishable step of the input signal. A signal of a lower level of the ADC will not register. In accordance with this, the resolution is identified with the sensitivity of the ADC. The conversion error has static and dynamic components. The static component includes the quantization methodological error Δ δ to (discreteness) and instrumental error from not ideal elements of converters. Quantization Error ∆ to due to the very principle of representing a continuous signal with quantized levels spaced apart by a selected interval. The width of this interval is the resolution of the converter. The greatest quantization error is half the resolution, and in the general case: (24)
Relative largest quantization error: (25)
The instrumental error should not exceed the quantization error. In this case, the total absolute static error is equal to: (26)
The total relative static error can be determined as: (27)
Next, we calculate the resolution of the built-in DAC of the PLC-150 microcontroller. The resolution of the DAC is the output voltage corresponding to one in the lower order of the input code: Δ \u003d U max /(2n -1), where 2 n -1 is the maximum weight of the input code. At U max \u003d 10B, n \u003d 10 (the capacity of the built-in DAC), we calculate the resolution of the DAC of the microcontroller: (28)
The larger n, the less Δ and more precisely, the input code can be represented by the output voltage. The relative value of the resolution of the DAC: (29
Figure 43 - Connection diagram Figure 44 - Connection diagram 2.6 Conclusion for the second chapter In this chapter, the development of a structural and functional diagram was made. The calculation of the regulatory body, the determination of the regulator settings and the synthesis of self-propelled guns were made. Parameters of the transfer function of the control object. Sensor equipment selected. A calculation was also made of the parameters of the ADC and DAC built into the microcontroller Aries PLC 150. 1 Development of an algorithm for the functioning of the NAC system in CoDeSys The professional development of industrial automation systems is inextricably linked with CoDeSys (Controller Development System). The main purpose of the CoDeSys complex is to develop application programs in the languages \u200b\u200bof the IEC 61131-3 standard. The complex consists of two main parts: the CoDeSys programming environment and the CoDeSys SP runtime system. CoDeSys runs on the computer and is used in the preparation of programs. Programs are compiled into fast machine code and loaded into the controller. CoDeSys SP works in the controller, it provides code loading and debugging, I / O servicing and other service functions. More than 250 well-known companies make equipment with CoDeSys. Every day thousands of people work with him, solving industrial automation problems. Application software for the PLC-150, as well as many other controllers, is developed on a personal computer in the CoDeSys environment running Microsoft Windows. The code generator directly compiles the user program into machine codes, which ensures the highest controller performance. The execution and debugging system, the code generator and the library of function blocks are specially adapted to the architecture of the PLC series controllers. Debugging tools include viewing and editing inputs and outputs and variables, running the program in cycles, monitoring the execution of the program algorithm in a graphical representation, graphically tracing the values \u200b\u200bof variables in time and events, graphical visualization and simulation of technological equipment. The main CoDeSys window consists of the following elements (in the window they are located from top to bottom): ) Toolbar. There are buttons on it for quick access to menu commands. ) An object organizer that has the POU, Data types, Visualizations, and Resources tabs. ) Separator of the Organizer of objects and the workspace CoDeSys. ) The workspace in which the editor is located. ) Message box. ) Status bar containing information about the current state of the project. The toolbar, message box and status bar are not required elements of the main window. The menu is at the top of the main window. It contains all the CoDeSys commands. The appearance of the window is shown in Figure 45. Figure 45 - The appearance of the window Buttons on the toolbar provide faster access to menu commands. The command called with the button on the toolbar is automatically executed in the active window. The command will be executed as soon as the button pressed on the toolbar is released. If you place the mouse pointer on a toolbar button, then after a short period of time you will see the name of this button in the tooltip. The buttons on the toolbar are different for different CoDeSys editors. You can get information on the purpose of these buttons in the description of the editors. The toolbar can be disabled, Figure 46. Figure 46 - Toolbar The general view of the CoDeSys program window is as follows, Figure 47. Figure 47 - CoDeSys program window The block diagram of the algorithm of operation in the CoDeSys environment is shown in Figure 48. Figure 48 - Block diagram of the operation in the environment CoDeSys As can be seen from the block diagram, after turning on the microcontroller, the program is loaded into it, the variables are initialized, the inputs are read and the modules are polled. There is also a choice of switching between automatic and manual mode. In manual mode, it is possible to control the valve and control the MEOF. Then there is a recording of the output data and the formation of packages on serial interfaces. After that, the algorithm goes into cycles to read the inputs or the work ends. 2 Development of the program in the environment of CoDeSys We launch Codesys and create a new project in ST language. The target file for ARM9 is already installed on the personal computer; it automatically selects the desired library. Communication with the controller is established. reg_for_meof: VALVE_REG; (* controller for controlling remote sensing devices *) K, b: REAL; (* regulation curve coefficients *) timer_for_valve1: TON; (* emergency shutdown timer *) safety_valve_rs_manual: RS; (* for manual valve control *) reference: REAL; (* setting the angle of rotation of the PDZ *) _ VAR (* during commissioning, we fix the signal from the MEOF position sensor and calculate the ain low ain high values, initially we assume that the sensor is 4-20 milliamps and at 4 mA - PDD is completely closed (0%), and at 20 mA - completely open (100%) - configured in the PLC configuration *) NOT auto_mode THEN (* if not automatic mode *) _ open: \u003d manual_more; (* open by pressing the button *) _ close: \u003d manual_less; (* close by pressing the button *) safety_valve_rs_manual (SET: \u003d valve_open, RESET1: \u003d valve_close, Q1 \u003d\u003e safety_valve); (* emergency valve control *) (* during commissioning, we fix the signal from the pressure sensor and calculate the ain low ain high values, initially we assume that the sensor is 4-20 milliamps and at 4 mA the tank is empty (0%), and at 20 mA it is full (100%) - it is configured in PLC configuration *) IF pressure_sensor< WORD_TO_REAL(w_reference1) THEN reference:=100; END_IF; (*если уровень меньше "w_reference1", то открываем заслонку на 100%*) IF pressure_sensor\u003e WORD_TO_REAL (w_reference1) THEN (* set the rotation angle - decrease proportionally to the increase in the pressure sensor level --- angle \u003d K * level + b *) K: \u003d (- 100 / (WORD_TO_REAL (w_reference2-w_reference1))); b: \u003d 100-K * (WORD_TO_REAL (w_reference1)); reference: \u003d K * pressure_sensor + b; (* timer for emergency shutter control *) timer_for_valve1 ( IN: \u003d (pressure_sensor\u003e WORD_TO_REAL (w_reference2)) AND high_level_sensor, (* condition for opening the emergency valve *) IF timer_for_valve1.Q reference: \u003d 0; (* close the MEOF *) safety_valve: \u003d TRUE; (* open the emergency valve *) safety_valve: \u003d FALSE; (* knob to control the damper *) _ for_meof ( IN_VAL: \u003d reference, POS: \u003d MEOF_position, DBF: \u003d 2, (* regulator sensitivity *) ReversTime: \u003d 5, (* no more than 600 inclusions *) MORE \u003d\u003e MEOF_open, LESS \u003d\u003e MEOF_close, FeedBackError \u003d\u003e); _ IF; (* data conversion for display in scud *) w_MEOF_position: \u003d REAL_TO_WORD (MEOF_position); _ level: \u003d REAL_TO_WORD (pressure_sensor); (* indication of the mode for filling auto-manual buttons *) _ out: \u003d auto_mode; (* indication of the output for filling the buttons close / open the emergency valve *) _ out: \u003d safety_valve; 3.3 Development of an interface for visual display of measurement information To develop the visual display interface, the Trace Mode 6 program was chosen, because it has all the functions and characteristics we need: has a fairly wide range of capabilities for simulating technological processes on a graphic screen; all standard programming languages \u200b\u200bfor SCADA-systems, controllers are available; friendly graphical interface; quite simple connection to a programmable logic controller; available full version of this system on the manufacturer's website. race Mode 6 is designed to automate industrial enterprises, energy facilities, intelligent buildings, transport facilities, energy metering systems, etc. The scale of automation systems created in Trace Mode can be anything from autonomous operating controllers and operator workstations to geographically distributed control systems that include dozens of controllers that exchange data using various communications - local network, intranet / Internet, serial buses to based on RS-232/485, dedicated and switched telephone lines, radio channel and GSM networks. The integrated project development environment in the Trace Mode program is shown in Figure 49. Figure 49 - Trace Mode 6 Integrated Development Environment The project navigator allows you to quickly jump between project sub-items. When you hover over one of the items, a comment appears that allows you to understand the contents. Figure 50 - Project Navigator The mimic diagram of the project, the storage tank of the first stage of wastewater treatment is shown in Figure 0. It includes: Control panel (the ability to select a control mode, the ability to control the dampers); Display of a rotation angle ПДЗ; Indication of water level in the tank; Emergency discharge (in case of water overflow in the tank); A graph for tracking measurement information (water level status and damper position are displayed on the graph). Figure 51 - Mimic diagram of the storage tank Under the "Position of the remote sensing position" field, the actual angle of rotation of the damper (0-100%) is displayed, which allows you to more accurately track the measurement information. Figure 52 - Position of remote sensing devices The arrows to the left of the tank change color from gray to green when PLC descends (signal from self-propelled guns), i.e. if the arrow is green then the water level is higher than the sensor. The slider on the scale is a level indicator (by metran pressure sensor) (0-100%). Figure 53 - Level Indicator Management can be carried out in two modes: ) Automatic. When choosing a mode, the color of the corresponding button changes color from gray to green and this mode becomes active for use. The "Open" and "Close" buttons are used to control valves in manual mode. In automatic mode, it is possible to set tasks on which the rotation angle of the remote sensing device will depend. To the right of the "task 1" field, a level is entered in the tank, at which the rotation angle of the remote sensing device will begin to decrease. To the right of the "task 2" field, a level is entered in the tank at which the remote sensing will be completely closed. The emergency valve also works in automatic mode in case of a possible overflow of water. The emergency valve opens if the level is exceeded above "task 2" and when the upper level sensor (ACS) is activated for 10 seconds. Figure 54 - Emergency Reset For ease of monitoring, measurement information, water level status, and damper position are displayed on a graph. The blue line shows the water level in the tank, and the red flap position. Figure 55 - Graph of the level and position of the shutter 4 Conclusions in the third chapter In the third chapter, the algorithm of the system’s functioning in the CoDeSys environment was developed, a block diagram of the system’s functioning was built, and a software module for input / output of information in the control system was developed. An interface was also developed for visual display of measurement information using the Trace Mode 6 program for an automatic control system. 4. Organizational - economic part 1 Cost-effectiveness of process control systems Economic efficiency - the effectiveness of the economic system, expressed in relation to the useful end results of its functioning to the expended resources. Production efficiency is the sum of the efficiency of all existing enterprises. The effectiveness of the enterprise is characterized by the production of goods or services at the lowest cost. It is expressed in its ability to produce the maximum volume of products of acceptable quality at the lowest cost and to sell these products at the lowest cost. The economic efficiency of the enterprise, in contrast to its technical efficiency, depends on how much its products meet the requirements of the market and the needs of consumers. Automated process control systems provide increased production efficiency by increasing labor productivity, increasing production volume, improving the quality of products, the rational use of fixed assets, materials and raw materials and reducing the number of employees in the enterprise. The introduction of SU differs from the usual work on the introduction of new technology in that it allows you to transfer the production process to a qualitatively new stage of development, characterized by a higher organization (ordering) of production. A qualitative improvement in the organization of production is due to a significant increase in the volume of information processed in the control system, a sharp increase in the speed of its processing and the use of more sophisticated methods and algorithms to develop control solutions than those that were used before the introduction of process control systems. The economic effect obtained from the introduction of the same system depends on the level of organization of production (stability and tuning of the technological process (TP)) before and after the introduction of process control systems, that is, it can be different for different enterprises. The rationale for the development (or implementation) of new equipment begins with a technical assessment, by comparing the designed design with the best of existing domestic and foreign models. High economic efficiency of a new device or device is achieved by laying in its design advanced technical solutions. They can be expressed by a system of technical and operational indicators characterizing this type of device. Progressive technical indicators are the basis for achieving high economic efficiency - the ultimate criterion for evaluating new technology. This does not detract from the importance of technical indicators in assessing economic efficiency. Usually, the economic indicators of the effectiveness of new equipment are few and uniform for all industries, and the technical indicators are specific to each industry and their number can be very large in order to comprehensively characterize the technical parameters of the products. Technical indicators reveal the extent to which the new device meets the need for product release or work, and to what extent it is linked to other machines that are used or designed for the same process. Before proceeding with the design (or implementation), it is necessary to thoroughly and comprehensively familiarize yourself with the purpose for which the device is created (implemented), study the technological process in which it will be used, and get a clear idea of \u200b\u200bthe amount of work to be performed by the new product. All this should be reflected in the technical assessment of the new machine (device) of the product. Assessment of the enterprise should take into account the results and costs of production. However, practice shows that the assessment of production links only with the help of indicators of the cost-effective approach does not always aim them at achieving high final results of activity, finding internal reserves and in fact does not contribute to increasing overall efficiency. 2 Calculation of the main costs of the management system When determining the economic efficiency of the introduction of mechanization and automation, answers should be received to the following questions: how technically and economically progressive the proposed means of mechanization and automation are and whether they should be accepted for implementation; what is the magnitude of the effect of the introduction into production. The main costs for the creation of the control system consist, as a rule, of the costs of the pre-design and design work Sn and the costs of the acquisition of special equipment installed in the control system. At the same time, the cost of design work includes, in addition to the costs associated with the development of the project, the costs of developing mathematical support and the introduction of control systems, and the cost of equipment - in addition to the cost of control computer equipment, devices for preparing, transmitting and displaying information, the cost of those nodes of technological equipment , the modernization or development of which is caused by the operating conditions of the equipment in the TP - APCS system. In addition to the costs of creating a control system, the enterprise also incurs the costs of its operation. Thus, the annual cost of SU: (30)
where T is the operating time; usually T \u003d 5 - 7 years; - annual operating costs, rubles. Operating costs for SU: (31)
where - the annual salary fund of personnel serving the SU, rubles .; - depreciation and payment for funds, rubles .; - costs of utilities (electricity, water, etc.), rub .; - annual costs of materials and components, rub. Depreciation and fund fees: (32)
where - the cost of equipment of the i-th type, rub .; - depreciation coefficient for the i-th type of equipment; - coefficient of deductions for funds. The annual salary fund of personnel serving the SU: (33)
where - the operating time of the maintenance personnel for the year, h; - the average hourly rate of staff, rubles .; - coefficient of shop overhead; m ′ - the number of service personnel and specialized devices of the technological equipment of personnel, people The cost estimate for the management system includes the following items of expenditure: costs of basic equipment; additional equipment costs; workers wages; deductions for social needs; cost of computer time; overhead. The basic salary of performers Sosn, rub, is determined by the formula: FROM main \u003d T ozh * t from * b, (34) where tс is the length of the working day, h (tс \u003d 8 h); - the cost is 1 person-h (determined by dividing the monthly salary by the number of hours to be worked out per month), rub-h. The average cost of 1 person-h is 75 rubles The complexity of the work is 30.8 people-days. FROM main \u003d 30.8 * 8 * 75 \u003d 18,480 rubles. (35) Additional salary Sdop, rub, is taken in the amount of 15% of the basic salary. Sdop \u003d 0.15 * 18 480 \u003d 2772 rubles. Deductions for social needs Sotch, rubles, are calculated from the amount of the main and additional wages in the amount of 26.2% FROM ot \u003d 0.262 * (C main + C additional ), (36)
Sotch \u003d 0.262 * (18480 + 2772) \u003d 5568 rub. Material costs see are: C1 - the cost of the PLC-150 Microcontroller (average cost is 10,000 rubles); C2 - the cost of the power supply (average cost is 1800 rubles); C3 - the cost of sensor equipment (average cost 4000 rubles); C4 - PC cost (average PC cost 15,000 rubles, Pentium DC E6700, GA-EG41MFT-US2H, 2 x 2GB, 500Gb); C5 - other expenses (consumables, wires, mounts, etc.); Cm \u003d C1 + C2 + C3 + C4 + C5 C1 \u003d 10,000 rub. C2 \u003d 1800 rub. C3 \u003d 4000 rub. C4 \u003d 15000 rub. C5 \u003d 9000 rub. Cm \u003d 10000 + 1800 + 4000 + 15000 + 9000 \u003d 39800 rub. Machine time - the period during which the machine (unit, machine tool, etc.) performs work on processing or moving the product without direct human exposure. The cost of computer time is determined by the formula: FROM mv \u003d T mash * C mch , (37)
where Tmash - time of use of technical means, h; Tsmch - the cost of a machine-hour, which includes depreciation of technical equipment, the cost of maintenance and repair, the cost of electricity, rub-h The time of use of technical means is equal to the laboriousness of the work of performers and is 412 hours. The cost of a machine hour Tsmch is 17 rubles. Smv \u003d 412 * 17 \u003d 7004 rubles. Overhead costs Snack include all costs associated with management and maintenance. There are no such costs in this case. The cost estimates for the development of the enterprise automated system are presented in table 0. Table 6 & Development costs Cost item Amount, RUB Percentage of the total Cost of materials 39800 54.2 Basic salary1848025.1 Additional salary27723.7 Social security contributions55687.5Cost of machine time70049.5Total 73624100 Thus, the costs of the management system are 73,624 rubles. Figure 56 - The main costs of the control system 3 Organization of production processes Organization of production processes consists in combining people, tools and objects of labor into a single process of production of material goods, as well as in ensuring a rational combination in space and time of the main, auxiliary and serving processes. One of the main aspects of the formation of the production structure is to ensure the interconnected functioning of all components of the production process: preparatory operations, basic production processes, and maintenance. It is necessary to comprehensively justify the most rational for specific production and technical conditions organizational forms and methods of implementing certain processes. The principles of organization of the production process are the starting points on the basis of which the construction, operation and development of production processes are carried out. The principle of differentiation involves the division of the production process into separate parts (processes, operations) and their assignment to the relevant departments of the enterprise. The principle of differentiation is opposed to the principle of combination, which means the unification of all or part of diverse processes for the production of certain types of products within a single site, workshop or production. Depending on the complexity of the product, the volume of production, the nature of the equipment used, the production process can be concentrated in any one production unit (workshop, site) or dispersed across several departments. The principle of concentration means the concentration of certain production operations for the production of technologically homogeneous products or the performance of functionally homogeneous work at individual workplaces, sections, in shops or enterprises of an enterprise. The feasibility of concentration of homogeneous work in individual production areas is due to the following factors: common technological methods that necessitate the use of the same equipment; equipment capabilities, such as machining centers; increase in output of certain types of products; economic feasibility of concentrating the production of certain types of products or performing homogeneous work. The principle of proportionality lies in the logical combination of the individual elements of the production process, which is expressed in a certain quantitative ratio of them with each other. Thus, the proportionality in production capacity implies the equality of the capacity of the sections or equipment load factors. In this case, the throughput capacity of the procurement workshops corresponds to the requirements for the blanks of the mechanical workshops, and the throughput of these workshops corresponds to the needs of the assembly shop in the necessary details. This implies the requirement to have in each workshop equipment, space, labor in such quantity that would ensure the normal operation of all departments of the enterprise. The same ratio of throughput should exist between the main production, on the one hand, and auxiliary and service units, on the other. 4.4 Conclusion in the fifth chapter In this chapter, in accordance with the assignment for the graduation project, the economic efficiency of the implementation of process control systems was determined. The main provisions were also considered and the basic costs of the management system were calculated. 5. Life safety and environmental protection 1 Life Safety When creating complex automated control systems, system design is increasingly practiced, at the early stages of which issues of workplace safety and ergonomic support are raised, which conceals large reserves for increasing the efficiency and reliability of the entire system. This is due to the comprehensive consideration of the human factor in the process of his stay in the workplace. The main objective of security measures is to protect human health from harmful factors, such as electric shock, insufficient lighting, increased noise in the workplace, increased or decreased air temperature of the working area, increased or decreased air humidity, increased or decreased air mobility. All this is achieved as a result of the implementation and implementation of a set of procedures and measures interrelated in meaning, logic and sequence that are carried out during the development of the human-machine system and during its operation. The theme of the diploma project is "An automated system for controlling the process of wastewater treatment after a car wash with the development of a software module for the Aries microcontroller." In connection with the specifics of this workplace, the enterprise carries out wastewater treatment with chlorine, and chlorine refers to accidentally chemically hazardous substances (AHOV). Therefore, to ensure the preservation of health and high labor productivity, it is necessary to investigate dangerous and harmful factors when working at the enterprise with the probability of AHOV emissions. Dangerous and harmful factors when working with AHOV Poisoning by accidental chemically hazardous substances (AHOV) in accidents and catastrophes occurs when AHOV enters the body through the respiratory and digestive organs, skin and mucous membranes. The nature and severity of the lesions are determined by the following main factors: the type and nature of the toxic effect, the degree of toxicity, the concentration of chemicals in the affected facility (territory) and the timing of exposure to humans. The above factors will determine the clinical manifestations of the lesions, which in the initial period may be: ) irritation phenomena - cough, sore throat and sore throat, lacrimation and pain in the eyes, chest pain, headache; ) increase and development of phenomena from the side of the central nervous system (CNS) - headache, dizziness, feeling of intoxication and fear, nausea, vomiting, euphoria, impaired coordination of movements, drowsiness, general lethargy, apathy, etc. Protection against dangerous and harmful factors To prevent the release of chlorine, the enterprise must strictly comply with safety regulations, instruct when handling AHOV and carry out controls for the admission of hazardous substances. The enterprise must have protective equipment in case of emergency. One of such means of protection is the gas mask GP-7. The gas mask is designed to protect the respiratory system, vision and face of a person from toxic substances, biological aerosols and radioactive dust (OM, BA and RP). Figure 57 - Gas mask GP-7 Gas mask GP-7: 1 - front part; 2 - filtering and absorbing box; 3 - knitted cover; 4 - inspiratory valve assembly; 5 - intercom (membrane); 6 - exhalation valve assembly; 7 - obturator; 8 - headgear (occipital plate); 9 - frontal strap; 10 - temporal straps; 11 - buccal straps; 12 - buckles; 13 - bag. Gas mask GP-7 is one of the latest and most advanced gas mask models for the population. Provides highly effective protection against vapors of poisonous, radioactive, bacterial, emergency chemically hazardous substances (AHOV). It has low breathing resistance, provides reliable sealing and low pressure of the front part on the head. Due to this, people over 60 years old and patients with pulmonary and cardiovascular diseases can use it. Figure 58 - time of protective action of GP-7 Figure 59 - Technical characteristics of GP-7 Chlorine accident When receiving information about the accident with AHOV, put on respiratory protective equipment, skin protection equipment (cloak, cape), leave the accident area in the direction indicated in the message on the radio (television). To leave the zone of chemical contamination should be in the direction perpendicular to the direction of the wind. At the same time, avoid crossing through tunnels, ravines and hollows - in low places the concentration of chlorine is higher. If it is impossible to get out of the danger zone, stay in the room and make emergency sealing: close windows, doors, ventilation openings, chimneys tightly, seal the cracks in the windows and at the joints of the frames and climb to the upper floors of the building. Figure 60 - Scheme of evacuation from the infection zone After leaving the danger zone, remove your outer clothing, leave it on the street, take a shower, rinse your eyes and nasopharynx. If signs of poisoning appear: rest, warm drink, consult a doctor. Signs of chlorine poisoning: sharp chest pain, dry cough, vomiting, pain in the eyes, lacrimation, impaired coordination of movements. Personal protective equipment: gas masks of all types, gauze dressing moistened with water or 2% soda solution (1 teaspoon per glass of water). Emergency care: remove the victim from the danger zone (transportation only lying down), free from clothing that makes breathing difficult, drink plenty of 2% soda solution, rinse eyes, stomach, nose with the same solution, and use 30% albucide solution in the eyes. Darkening the room, dark glasses. 5.2 Environmental protection Human health directly depends on the environment, and primarily on the quality of the water that he drinks. Water quality affects the life of the human body, its performance and overall well-being. Not without reason, ecology and, in particular, the problem of clean water has received so much attention. In our time of developed technological progress, the environment is becoming more and more polluted. Particularly dangerous is the pollution of wastewater by industrial enterprises. The most common wastewater pollutants are petroleum products - an unidentified group of hydrocarbons of oil, fuel oil, kerosene, oils and their impurities, which, due to their high toxicity, belong, according to UNESCO, to the ten most dangerous environmental pollutants. Petroleum products can be in solutions in emulsified, dissolved form and form a floating layer on the surface. Oil Pollution Factors One of the environmental pollutants is oily wastewater. They are formed at all technological stages of oil production and use. The general direction of solving the problem of preventing environmental pollution is the creation of non-waste, low-waste, drainless and low-waste industries. In this regard, during the acceptance, storage, transportation and distribution of petroleum products to consumers, all necessary measures must be taken to prevent or reduce their losses as much as possible. This problem should be solved by improving the technical means and technological methods of oil and oil products processing at oil depots and pumping stations. Along with this, local prefabricated devices for various purposes can play a useful role, allowing you to collect spills or leaks of products in their pure form, preventing their removal with water. With limited possibilities for using the aforementioned products at oil depots, wastewater contaminated with oil products is formed. In accordance with the requirements of existing regulatory documents, they are subject to rather deep cleaning. The technology for purification of oily water is determined by the phase-dispersed state of the resulting oil-water system. The behavior of petroleum products in water is caused, as a rule, by their lower density in comparison with the density of water and extremely low solubility in water, which is close to zero for heavy varieties. In this regard, the main methods of water purification from oil products are mechanical and physico-chemical. Of the mechanical methods, sedimentation has found the greatest application, and filtering and centrifugation to a lesser extent. Of the physicochemical methods, flotation, which is sometimes referred to as mechanical methods, attracts serious attention. Wastewater treatment of oil products by sedimentation tanks and sand traps Sand traps are designed to isolate mechanical impurities with a particle size of 200-250 microns. The need for preliminary separation of mechanical impurities (sand, scale, etc.) is due to the fact that in the absence of sand traps, these impurities are released in other treatment plants and thereby complicate the operation of the latter. The principle of operation of the sand trap is based on a change in the speed of movement of solid heavy particles in a fluid stream. Sand traps are divided into horizontal, in which the liquid moves in a horizontal direction, with rectilinear or circular motion of water, vertical, in which the liquid moves vertically upward, and sand traps with screw (translational-rotational) movement of water. The latter, depending on the method of creating a helical movement, are divided into tangential and aerated ones. The simplest horizontal sand traps are tanks with a triangular or trapezoidal cross-section. The depth of the sand traps is 0.25-1 m. The water velocity in them does not exceed 0.3 m / s. Sand traps with a circular motion of water are made in the form of a round conical tank with a peripheral tray for the flow of waste water. Sludge is collected in a conical bottom, from where it is sent for processing or dump. They are used at flow rates up to 7000 m3 / day. Vertical sand traps have a rectangular or round shape, in them the wastewater moves with a vertical upward flow at a speed of 0.05 m / s. The design of the sand trap is chosen depending on the amount of wastewater, the concentration of suspended solids. The most commonly used horizontal sand traps. From the experience of oil depots, it follows that horizontal sand traps must be cleaned at least once every 2-3 days. When cleaning sand traps, a portable or stationary hydraulic elevator is usually used. Sedimentation is the simplest and most frequently used method for the separation of coarsely dispersed impurities from wastewater that, under the influence of gravitational force, settle on the bottom of the sump or float on its surface. Oil transportation enterprises (oil depots, oil pumping stations) are equipped with various sedimentation tanks for collecting and purifying water from oil and oil products. For this purpose, standard steel or reinforced concrete tanks are usually used, which can operate as a storage tank, a settling tank or a buffer tank, depending on the technological scheme of wastewater treatment. Based on the technological process, the contaminated waters of oil depots and oil pumping stations unevenly flow to treatment facilities. For a more uniform supply of contaminated water to treatment plants, buffer tanks are used, which are equipped with water distribution and oil collecting devices, pipes for supplying and discharging waste water and oil, a level gauge, breathing apparatus, etc. Since oil in water is in three states (easily, difficult to separate and dissolved), once in the buffer tank, easily and partially difficult to separate oil floats to the surface of the water. Up to 90-95% of easily separable oils are separated in these tanks. For this, two or more buffer tanks are installed in the treatment plant scheme, which operate periodically: filling, sludge, pumping. The volume of the tank is selected from the calculation of the time of filling, pumping and sludge, and the time of sludge is taken from 6 to 24 hours. Thus, buffer tanks (sump tanks) not only smooth the uneven flow of wastewater to the treatment plant, but also significantly reduce the concentration of oil water. Before pumping out the settled water from the reservoir, the emerging oil and precipitated sediment are first removed, after which clarified water is pumped out. To remove sediment at the bottom of the tank, drainage is made from perforated pipes. A distinctive feature of dynamic sedimentation tanks is the separation of impurities in the water during fluid movement. In dynamic settling tanks or continuous settling tanks, the fluid moves in a horizontal or vertical direction, hence the settling tanks are divided into vertical and horizontal. The vertical sump is a cylindrical or square (in plan) tank with a conical bottom for the convenience of collecting and pumping out the precipitated sediment. The movement of water in the vertical sump occurs from the bottom up (for deposited particles). The horizontal sump is a rectangular tank (in plan) 1.5-4 m high, 3-6 m wide and up to 48 m long. Precipitate deposited at the bottom is moved to the pit with special scrapers and removed from it with a hydraulic elevator, pumps or other devices. sedimentation tank. Surfaced impurities are removed with the help of scrapers and transverse trays installed at a certain level. Depending on the product being trapped, horizontal sumps are divided into sand traps, oil traps, oil traps, gas traps, grease traps, etc. Some types of oil traps are shown in Figure 0. Figure 61 - Oil traps In circular circular sumps, water moves from the center to the periphery or vice versa. High-capacity radial sumps used for wastewater treatment have a diameter of up to 100 m and a depth of 5 m. Radial sumps with a central wastewater inlet have increased inlet speeds, which leads to less efficient use of a significant part of the volume of the sump in relation to radial sumps with a peripheral wastewater inlet and purified water in the center. The greater the height of the sump, the more time is required for the particle to surface on the surface of the water. And this, in turn, is associated with an increase in the length of the sump. Therefore, it is difficult to intensify the process of sedimentation in oil traps of conventional structures. With an increase in the size of sedimentation tanks, the hydrodynamic characteristics of sedimentation deteriorate. The thinner the liquid layer, the process of ascent (subsidence) occurs faster, ceteris paribus. This position led to the creation of thin-layer sedimentation tanks, which by design can be divided into tubular and lamellar. The working element of the tubular sump is a pipe with a diameter of 2.5-5 cm and a length of about 1 m. The length depends on the characteristics of pollution and the hydrodynamic parameters of the flow. Apply tubular sumps with a small (10) and large (up to 60) slope of the pipes. Sumps with a small slope of the pipe work on a periodic cycle: clarification of water and flushing pipes. It is advisable to use these settlers for clarification of wastewater with a small amount of mechanical impurities. The clarification efficiency is 80-85%. In steeply inclined tubular sumps, the location of the tubes causes the sediment to slide down the tubes, and therefore there is no need to flush them. The duration of the sumps practically does not depend on the diameter of the tubes, but increases with increasing length. Standard tubular blocks are made of polyvinyl or polystyrene plastic. Usually, blocks are used with a length of about 3 m, a width of 0.75 m and a height of 0.5 m. The size of the tubular element in the cross section is 5x5 cm. The designs of these blocks allow you to mount sections of them for any performance; sections or individual blocks can easily be installed in vertical or horizontal settling tanks. Lamellar sumps consist of a series of parallel mounted plates between which fluid moves. Depending on the direction of movement of water and precipitated (surfaced) sediment, sedimentation tanks are divided into direct-flow, in which the directions of movement of water and sediment coincide; countercurrent, in which water and sediment move towards each other; cross, in which water moves perpendicular to the direction of sediment movement. The most widespread are plate countercurrent sedimentation tanks. Figure 62 - Sumps The advantages of tubular and plate sumps are their efficiency due to the small construction volume, the possibility of using plastics that are lighter than metal and do not corrode in aggressive environments. A common drawback of thin-layer sedimentation tanks is the need to create a tank for preliminary separation of easily separated oil particles and large clots of oil, scale, sand, etc. Clots have zero buoyancy, their diameter can reach 10-15 cm at a depth of several centimeters. Such clots very quickly disable thin-layer sedimentation tanks. If some of the plates or pipes are clogged with such clots, then the rest will increase the flow of fluid. This situation will lead to deterioration of the sump. Schematic diagrams of sedimentation tanks are shown in Figure 0. 5.3 Conclusions in the fifth chapter In this section, the main issues of life safety and environmental protection were considered. An analysis of hazardous and harmful production factors was carried out. The development of protective measures for the release of chlorine was also carried out. In addition, in this chapter the main tasks for protecting the environment were considered, the installation of a horizontal sump was proposed for the treatment of wastewater from oil products. Conclusion In this graduation project, the software was developed for the system of automatic control of wastewater treatment after a car wash. The basics of functioning and modern methods of wastewater treatment were considered. And also the ability to automate these processes. An analysis was made of existing hardware (logic programmable PLC controllers) and software for control systems. The hardware of the control system for controlling the car wash wastewater treatment process has been developed. An algorithm for the functioning of the system in the CoDeSys environment is developed. A visual display interface has been developed in the Trace Mode 6 environment. List of references automation wastewater treatment 1. Lectures on the courses "Electronics" and "Technical Measurements and Instruments". Kharitonov V.I. 2. "Management of technical systems" Kharitonov VI, Bunko EB, K.I. Mesha, E.G. Murachev. 3. "Electronics" Savelov N.S., Lachin V.I. Technical documentation for car washing MGUP Mosvodokanal. Zhuromsky V.M. Course of lectures on the course "Technical means" Kazinik E.M. - Guidelines for the implementation of the organizational and economic part - Moscow, publishing house MSTU MAMI, 2006. - 36p. Sandulyak A.V., Sharipova N.N., Smirnova E.E. - Guidelines for the implementation of the section "life safety and environmental protection" - Moscow, publishing house MGTU MAMI, 2008. - 22 p. Technical documentation MGUP "Mosvodokanal" Stakhov - Treatment of oily wastewater from oil storage and transportation enterprises - Leningrad Nedra. Website resources http://www.owen.ru.
The method relates to the field of automation of wastewater treatment processes, in particular for the treatment of effluents from industrial enterprises. The method includes neutralizing the effluent by supplying either an acid solution or an alkali solution to achieve a predetermined pH value. An acid solution or an alkali solution is fed to an industrial effluent reservoir. The drains, depending on their concentration, enter either the electrocoagulator or the galvanocoagulator for cleaning. Regulation of the quality of cleaning in the electrocoagulator is carried out by regulating the current depending on the conductivity of the effluent. After that, the deposition process is carried out by flowing effluents from the sump to the sump using electric valves. To accelerate the deposition process, polyacrylamide is fed, undissolved sediment is passed through salt filters and fine filters, then dehydrated, and clean effluents enter the galvanic coating line. This method allows to improve the quality of industrial wastewater treatment for use in the reverse cycle. 1 ill.
The invention relates to the field of automation of wastewater treatment processes, in particular for wastewater treatment of industrial enterprises. A method is known for automatically controlling the coagulation process by simultaneously controlling the flow of acid and coagulant into the reactor and controlling the color of water, while the coagulant flow rate is controlled depending on the color of water on reactor outlet and acid consumption depending on the pH value of the water at the reactor outlet (SU 1655830 A1, 06/15/1991). However, this method does not achieve complete precipitation e ions, which reduces the quality of cleaning. A method is known for automatically controlling the process of wastewater treatment of industrial enterprises, including measuring the pH of purified water, regulating the flow rate into the apparatus, while measuring the oxidation-reduction potential of the purified water, generating a regulator installation signal, comparing it with a given value works, as a result of which they generate an inconsistency signal and regulate the flow rate of industrial enterprises using the regulator through the device source, depending on the amount of mismatch of the experimentally established dependence (RU 2071951 C1, 01/20/1997). The disadvantage of this method is the low quality of industrial wastewater treatment, the inability to use them in the reverse cycle. The technical result achieved by the implementation of this invention is to improve the quality of cleaning industrial effluents for using the latter in the reverse cycle. The technical result is achieved by the fact that in the method of automatically controlling the effluent treatment process According to the invention, an acid solution or an alkali solution is fed to an industrial effluent storage tank, then the effluent, depending on their concentration, is either supplied to an electrocoagulator or galvanocoagulator for cleaning, moreover, the quality control of cleaning in the electrocoagulator is carried out by regulating the current depending on the conductivity of the effluent, after which the deposition process is carried out after polyacrylamide is fed into the sump using the electric valves to accelerate the deposition process, undissolved sludge is passed through salt filters and fine filters, then dehydrated, and the clean drains enter the galvanic coating line. Comparison of the claimed invention with the known that the use of existing automation methods does not allow the treatment of wastewater from heavy metal ions, which makes it impossible to introduce purified kov into the enterprise’s working cycle, while in the claimed invention there is a complete purification of industrial wastewater, which is carried out stepwise under the control of various sensors, allowing to neutralize the effluents at the first stage, then subject them to electrocoagulation or galvanocoagulation, while controlling the quality of treatment using alternating electric current by supplying saline, dewater the sediment and then use it, for example, in galvanic com production, and use the separated water in the circulating water supply. The automation wastewater treatment automation scheme shown in the drawing includes: a wastewater accumulator 1, a level 2 sensor, a level 3 indicator, an acid metering tank 4, an electric valve 5, an alkali metering tank 6, an electric valve 7, a wastewater pump 8, an electric coagulator 9 , galvanic coagulator 10, electric valve 11, saline solvent 12, electric lock 13, sedimentation tanks 14, polyacrylamide metering tank 15, electric valve 16, container for treated wastewater 17, salt filter 18, fine filter 19, purified pump shackles 20, an electric gate valve 21, a sludge dewatering processor 22, a pH meter 23 sensor, a pH meter 24, a DC ammeter 25 of the rectifier unit of the electrocoagulator, a meter 27, electrodes 27, an ohmmeter 28, a level sensor 29, a level switch 30. The method is implemented as follows. Production wastewater, for example, the wastewater from the galvanic shop, is fed to the wastewater accumulator 1. Upon reaching the specified upper level in the wastewater accumulator 1, the level 2 sensor gives an impulse to the level 3 signaling device, which in turn q gives the command to prepare the effluents for treatment with a given pH value. To do this, either the acid solution from the metering tank 4 by means of an electric valve 5 or the alkali solution from the metering tank 6 by means of an electric valve 7 is automatically supplied to the effluent reservoir 1. After reaching the preset pH in the effluent reservoir 1, which is detected using a pH sensor 23 meters with a pH meter regulating 24, a pH meter regulating 24 gives a command to turn on the sewage feed pump 8. Depending on the concentration of the effluents, the latter are fed either to an electrocoagulator 9 (at high concentration) or to a galvanocoagulator 10 (at medium or low concentration indicators), where wastewater is treated. The quality of wastewater treatment in the electrocoagulator is regulated by regulating the current in the electrocoagulator by supplying salt solution from the salt solvent 12 to the drain 1, by means of an electric valve 11 controlled by a regulating ammeter 26, connected to the output of a direct current ammeter 25 of the rectifier unit of the electrocoagulator, in order to change the conductivity of the drains, fed into the electrocoagulator 9. If, during the cleaning process, the value of the electric current in the electrocoagulator 9 drops below At the set value, the electric valve 11 automatically opens and the current reaches the set value. If during the cleaning process the value of the electric current in the electrocoagulator 9 rises above the set value, the electric valve 11 automatically closes and the current decreases to the set value.The quality of the wastewater treatment in the galvanic coagulator is controlled by regulating the flow of wastewater into the galvanic coagulator using the electric valve 21 depending on the concentration of the effluent. Monitoring and regulation of the concentration of wastewater in the accumulator 1 is carried out using a sensor 27 and an ohmmeter regulating 28. To exclude the discharge of untreated effluents from the electrocoagulator 9 in emergency situations (for example, clogging of the pipeline when saline is supplied to the drain accumulator 1), the electric lock 13 is turned on. if the value of the electric current in the electrocoagulator 9 for a critical time is below the set value, the wastewater pump 8 is automatically turned off, while the accident lights up a clear light panel, the flow of wastewater stops. The treated effluent from the electrocoagulator 9 and the galvanic coagulator 10 flows by gravity to the first settler 14, where insoluble sediment settles. To accelerate the sedimentation process, polyacrylamide is automatically fed into the first settler 14 from the metering tank 15 by means of an electronic shutter 16. For a more complete precipitation of undissolved sediment, the 2nd and 3rd settlers 14 are connected in series with each other. Such a settling system allows maximum sedimentation undissolved sludge. After the sedimentation process is carried out in the system of sedimentation tanks, drains by gravity enter the tank for treated effluents 17. The levels in the tank for treated effluents are signalized 17 It is indicated by level gauges 29 with level 30. When the drains reach the upper level 29 in the tank for treated wastewater 17, the pump 20 automatically turns on, which feeds the wastewater to the salt filter 18, and then to the fine filter 19, from where the clean wastewater enter galvanic coating lines or technological schemes of other industries.
Claim
A method for automatically controlling the effluent treatment process of industrial enterprises, including neutralizing the effluent by supplying either an acid solution or an alkali solution to achieve a predetermined pH value, characterized in that the acid solution or alkali solution is fed into the industrial effluent reservoir, then the effluents are delivered depending on their concentration or in an electrocoagulator, or in a galvanic coagulator for cleaning, and the quality of cleaning in the electrocoagulator is regulated by adjusting the current depending on electrical conductivity of the effluent, after which the precipitation process is carried out by flowing the effluent from the sump to the sump using electric valves, to accelerate the deposition process, polyacrylamide is fed, undissolved sludge is passed through salt filters and fine filters, then dehydrated, and clean drains enter the galvanic line coverings.
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