Automation of management 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.

An exponential model for reducing the concentration of phenolic compounds, identified in the software environment Statistica . In order to stabilize the unstable parameters of the model, the idea of A.N. Tikhonov, the procedure of "ridge regression" was carried out. The resulting regularized model, which establishes the dependence of the degree of decomposition of phenolic compounds in an aqueous medium under the action of physicochemical factors (photo-Fenton reagent) on the process parameters, is statistically significant (R2 = 0.9995) and has improved predictive properties than the model identified by least squares method. Using a regularized model for reducing the concentration of phenolic compounds using the Lagrange multiplier method in the MathCad system, specific optimal levels of FeCl3, H2O2 consumption were determined, which ensured a decrease in the concentration of phenolic compounds in wastewater to the maximum allowable level.

regularization

incorrect tasks

modeling

wastewater

advanced oxidation 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 difficult to oxidize organic compounds. Phenol is a potentially dangerous, carcinogenic substance that poses a significant medical problem, even at low concentrations.

Advanced Oxidation Processes (AOPs) play an important role in the decomposition of organic matter contained 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 = 2.80 V) and is capable of reacting 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 oxidation processes occurs mainly in photochemical reactors. Photochemical reactors are devices in which photochemical reactions are carried out. But not only transformations take place in them, but also accompanying processes of mass and heat transfer and intensive movement of the medium occur. The effectiveness and safety of the cleaning process to the greatest extent depends on the correct choice of the type of reactor, its design and operating mode.

When using photoreactors for solving various applied problems, large volumes of reagents must be efficiently irradiated in them.

An important element of the photochemical purification module in common system local treatment facilities is a dosing system for reagents, catalyst FeCl 3 and hydrogen peroxide H 2 O 2 .

For the stable operation of reactors and increasing 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 to carry out the supply of reagents, taking into account the environmental management of the cleaning process. The function of the dependence of the concentration of an organic pollutant on the parameters of the process (concentrations of reagents and the time of UV irradiation), limited by the maximum permissible value of the concentration of a phenolic compound, can act as an ecological regulator. The concentration function is determined on the basis of a statistical analysis of the experimental data of the AOR process by the least squares method (LSM).

Often, the problem of determining the parameters of the regression equation by the least squares method is incorrectly formulated, and the use of the resulting equation in solving the optimization problem of determining the optimal doses of reagents can lead to inadequate results.

Thus, the aim of this work is to apply regularization methods to build a stable model of the dependence of the concentration of a phenol compound on the parameters of the photochemical purification process and identify the optimal levels of hydrogen peroxide and iron (III) chloride consumption while minimizing the cost of reagents.

To build a mathematical model of the dependence of the decrease in the concentration of a phenolic compound on the parameters of the AOP process under the combined effect of hydrogen peroxide, iron (III) chloride and ultraviolet radiation at a wavelength of 365 nm on a phenolic pollutant in an aquatic environment in order to solve the optimization problem for identifying the levels of consumption of chemical reagents, we carried out experimental studies on model solutions containing phenolic compounds (bisphenol-A, BPA), using liquid and gas chromatography. When carrying out the optimal planning of the experiment, the influence of UV radiation and oxidizing agents on the level of decomposition of the organic pollutant was evaluated at various concentrations of BPA - x1 (50 µg/l, 100 µg/l); hydrogen peroxide H 2 O 2 - x2 (100 mg / l; 200 mg / l) and an activator - iron chloride (III) 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 BPA concentration (y) was measured. The measurements were carried out with an LC-MS/MS liquid chromatograph. The half-life products during the photodegradation of BPA 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 medium at pH = 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 irradiation, the complex undergoes decomposition, resulting in the formation of the OH ● radical and the Fe 2+ ion:

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 the aquatic environment, can be described by the model:

where 0 - initial concentration of organic pollutant; 0 , 0 - initial concentrations of the activator containing iron (II) ions and hydrogen peroxide, respectively; k is the reaction rate constant; r is the reaction rate; α, β, γ - orders of reaction by substances.

When creating a mathematical model of the dependence of the decrease in the concentration of a phenolic compound 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 terms of coefficients using a suitable transformation, which can be written in a general form in the following way :

where fi(x1, x2, …, xm) are arbitrary functions of factors (regressors); β1, β2,…, βk - coefficients of the model; ε - experiment error.

Based on the law of mass action, the dependence of the concentration of the phenol compound on the factors of the process 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 VPA, mg/l; x2 - concentration of hydrogen peroxide, mg/l; x3 is the concentration of iron (III) chloride, g/l; x4 - cleaning process time, h; β1, β2, β3, β4, β5 - model parameters.

The coefficients in model (2) enter non-linearly, but when linearized by taking the logarithm in the natural base, the right and left parts of equation (2), we obtain

where according to (1)

However, with such a transformation, a random perturbation (experimental error) enters the model multiplicatively and has a lognormal distribution, i.e. , and after taking the 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 = lny, X1 = 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 data processing problems, the experiment matrix and the response vector are known inaccurately, i.e. with errors, and the task of determining regression coefficients using the least squares method is unstable to errors in the initial data. When the FTF information matrix (F is the regressor matrix) is ill-conditioned, the OLS estimates are usually unstable. To overcome the bad conditionality of the information matrix, the idea of regularization was proposed, justified in the works of A.N. Tikhonov.

As applied to solving regression problems, the idea of regularization by A.N. Tikhonov was interpreted by A.E. Hoerl as a "ridge regression" procedure. When using the "ridge regression" method to stabilize the least squares estimates (defined by b = (FTF)-1FTY), regularization is associated with adding some 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 be carried out as follows:

where m is the number of parameters (excluding free term) in the original regression model; SSe is the residual sum of squares obtained from the original regression model without adjusting for multicollinearity; b* - column vector of regression coefficients, transformed by the formula

where bj is the parameter for the variable Xj in the original regression model, determined by the least squares; - mean j-th independent variable.

After choosing the value of τ, the formula for estimating the regularized regression parameters will look like

where I is the identity matrix; F - matrix of regressors; Y - vector of dependent variable values.

The value of the regularization parameter, determined by formula (4), takes a value equal to τ = 1.371 10-4.

A regularized model for reducing the concentration of a phenolic compound, built in the Statistica system, taking into account formula (5), can be represented as

where C ost and C BPA are the residual and initial concentrations of the phenolic pollutant, respectively, mg/l; - concentration of hydrogen peroxide, mg/l; SA - concentration of iron (III) chloride, g/l; t - time, h.

The values of the coefficient of determination, R 2 = 0.9995, Fisher's criterion F = 5348.417, exceeding the critical value (F cr (0.01; 4.11) = 5.67), characterize the adequacy of the regularized model to the experimental results at the significance level α = 0.1.

Determination of the optimal specific values of the concentrations of chemical reagents (FeCl 3 , H 2 O 2) required for water treatment, when the minimum specific cost level is reached, is a non-linear (convex) programming problem of the form (7-9):

(8)

where f is the function of financial resources associated with the stock of chemicals f = Z(c2, c3); gi is the function of reducing the concentration of the phenol compound in the aquatic environment in the process of physical and chemical purification, g = Cost(с1, c2, c3, t) (limiting function); x1, x2,…, xn - process parameters; x1 is the initial concentration of the phenolic compound, x1 = c1, mg/l; x2 and x3 are the concentrations of hydrogen peroxide and iron (III) chloride, respectively x2 = c2, mg/l, x3 = c3, g/l; t - time, h; bi is the maximum permissible concentration of a phenolic compound (MAC), mg/l.

The function of financial resources, which represents a two-item model of costs 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 - specific overhead costs of one general delivery, rub.; c2 - specific consumption of hydrogen peroxide, mg/l; c3 - specific consumption of ferric chloride, g/l; I1, I2 - specific tariffs for the cost of storing hydrogen peroxide and iron (III) chloride, respectively, rub.; m1, m2 - the share of the product price attributable to the cost 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 - specific purchase price of a unit of stock of hydrogen peroxide (ruble/mg) and iron chloride (III) (ruble/g), respectively.

To solve system (7)-(9), a set of variables λ1, λ2, …, λm, called Lagrange multipliers, is introduced, which constitute the Lagrange function:

find partial derivatives and and consider the system of n + m equations

(11)

with n + m unknowns x1, x2, ..., xn; λ1, λ2, ..., λm. Any solution of the system of equations (11) determines a conditionally stationary point at which the extremum of the function f(x1, x2, ..., xn) can take place. If the Kuhn-Tucker conditions (12.1)-(12.6) are met, the point is a saddle point of the Lagrange function, i.e. the found solution of problem (7)-(9) is optimal:

The task of identifying the optimal parameters of the process of industrial wastewater treatment from phenolic compounds while reaching the minimum level of current unit costs required for dephenolization of water was solved with the following initial data: the initial concentration of a phenolic pollutant in wastewater is 0.006 mg/l (6 MPC); cleaning time determined by the technological process - 5 days (120 hours); maximum permissible concentration of pollutant 0.001 mg/l (b = 0.001); unit purchase price for hydrogen peroxide 24.5 10 ‒6 rubles/mg (k2 = 24.5 10 ‒6), for iron (III) chloride 37.5 10 ‒3 rubles/g (k3 = 37.5 10 – 3); the share of the product price attributable to the costs of maintaining the stock of hydrogen peroxide and ferric chloride is 10% (i = 0.1) and 12% (i = 0.12), respectively; the share of the product price attributable to the cost of fulfilling the order for hydrogen peroxide and ferric chloride is 5% (m1 = 0.05) and 7% (m2 = 0.07), respectively.

Solving problem (7)-(9) in the MathCad system, we obtain a point X* with coordinates

(с2*, с3*, λ*) = (6.361∙103; 5.694; 1.346 10 4),

in which the Kuhn-Tucker conditions (12.1)-(12.6) are satisfied. There is a point belonging to the region of feasible solutions at which the Slater regularity condition is satisfied:

Сost(c2°, c3°) = Сost (10 3 ,1) = - 7.22 10 -9< 0.

The type of a conditionally stationary point was determined in accordance with the Sylvester criterion in relation to the Hessian matrix of the Lagrange function:

In accordance with the Sylvester criterion, the matrix L is neither positively nor negatively definite (semi-definite) (Δ 1 = 4.772 10 -8 ≥ 0; Δ 2 = 6.639 10 -9 ≥ 0; Δ 3 = ‒5.042 10 -17 ≤ 0).

From the fulfillment of the Kuhn-Tucker conditions, Slater's 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 of 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 current costs of 1.545 rubles/l will be required. This value of specific costs is minimal when using optimal specific consumption levels of hydrogen peroxide 6.361·10 3 mg/l and iron (III) chloride 5.694 g/l in the purification process.

Using the Lagrange multiplier method for technical and economic conditions (c 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 rub./g; i 1 = 10%, i 2 = 12%; m 1 = 5%, m2 = 7%) phenolic compound contained in industrial wastewater up to the MPC level.

The identified regularized mathematical model, which establishes the dependence of the level of reduction in the concentration of a phenolic compound in an aqueous medium on the parameters of the photochemical purification process, 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 was solved to determine the estimates of the optimal specific consumption levels of chemical reagents (FeCl 3 , H 2 O 2), which are stable solutions.

The considered approach to identifying the optimal parameters of the photochemical purification process using regularization will make it possible to provide effective management wastewater treatment from phenolic compounds.

Reviewers:

Yashin A.A., Doctor of Technical Sciences, Doctor of Biological Sciences, Professor of the 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. L.N. Tolstoy, Tula.

The work was received by the editors on February 16, 2015.

Bibliographic link

Sheinkman L.E., Dergunov D.V., Savinova L.N. IDENTIFICATION OF PARAMETERS OF PHOTOCHEMICAL TREATMENT OF INDUSTRIAL WASTEWATER FROM PHENOLIC POLLUTANTS USING REGULARIZATION METHODS // Fundamental Research. - 2015. - No. 4. - P. 174-179;
URL: http://fundamental-research.ru/ru/article/view?id=37143 (date of access: 09/17/2019). We bring to your attention the journals published by the publishing house "Academy of Natural History"

Mechanical cleaning processes include filtering water through grates, sand trapping and primary settling. Structural scheme automation of mechanical wastewater treatment processes is shown in fig. 52.

Fig.52. Structural diagram of ACS:

1 - distribution chamber; 2 – grid of stepped pita; 3 - horizontal sand trap; 4 - primary sedimentation tank; 5 - sand bunker

Grids are used to capture large mechanical impurities from wastewater. When automating screens, the main task is to control rakes, crushers, conveyors and gates on the inlet channel. Water passes through the grate, on which mechanical impurities are retained, then, as waste accumulates, the stepped grate turns on and is cleaned of waste. Automatic devices on the grates turn on when the difference in wastewater levels before and after the grates increases. The angle of inclination of the grating is 60 about -80 about. The rake is turned off either by a contact device that is triggered when the level drops to a predetermined value, or with the help of a time relay (after a certain period of time).

Further, after the retention of large mechanical impurities, the runoff is sent to sand traps, which are designed to capture sand and other undissolved mineral contaminants from wastewater. The principle of operation of the sand trap is based on the fact that under the influence of gravity particles, specific gravity which are more than the specific gravity of water, as they move along with the water, fall to the bottom.

The horizontal sand trap consists of a working part where the flow moves and a sedimentary part, the purpose of which is to collect and store the precipitated sand until it is removed. waste water movement 0.1 m/s. Automatic devices in sand traps are used to remove sand when it reaches the limit level. For normal and effective work sand traps, it is necessary to monitor and control the level of sediment, if it rises above the permissible value, then it will be stirred up, and the water will be polluted by previously settled substances. Also, automatic sand removal can be carried out at certain intervals established on the basis of operating experience.

The effluent then enters the primary clarifier to retain floating and precipitating substances. Water slowly moves from the center to the periphery and merges into a peripheral trough with flooded holes. .To remove sediment from sewage, a slowly rotating metal truss is used with scrapers mounted on it, raking the sediment to the center of the sump, from where it is periodically pumped out by a hydraulic elevator. The residence time (settling) of the waste liquid is taken 2 hours, the speed of water movement is 7 m/s.

Automation of the process of physical and chemical wastewater treatment

In wastewater treatment systems by physical and chemical methods, pressure flotation is most widely used. With this method of purification, wastewater is saturated with gas (air) under excess pressure, which then quickly decreases to atmospheric pressure.

On fig. 53 shows a block diagram of the ACP with the stabilization of the quality of purified water by changing the flow rate of the recirculation flow, which carries the fine gas phase to the flotation cell.

The system consists of a flotation tank 1, a turbidity meter 2-1, which measures the concentration of suspended particles in purified water, a signaling device 2-3, a flow meter 1-1, a regulator 1-2, control valves 1-3, which regulates the flow of waste water entering the flotator , and valve 2-2, which regulates the flow rate of the circulation flow saturated with air in the pressure receiver 2.

The signal that occurs when the concentration of suspended solids in water at the outlet of the flotator increases above a predetermined value is sent from the turbidity meter 2-1 to the regulator, which through valve 2-2 increases the recirculation flow rate. The new amount of gas reduces the turbidity of the treated effluents. At the same time, as the flow rate of the recirculation through the flotation tank increases, a deviation signal appears at the output of the flowmeter 1-1, which is fed to the regulator 1-2. This regulator after 1-3 reduces the flow of waste water into the skimmer, ensuring the constancy of the total flow through it.

Rice. 53. Scheme of the ACP of the process of wastewater treatment by pressure flotation

Introduction

1. Structure of automatic control systems

2. Supervisory control

3. Control of the work of treatment facilities

Bibliographic list

Introduction

Automation of biological wastewater treatment - the use of technical means, economic and mathematical methods, control and management systems, partially or completely freeing a person from participating in the processes occurring in sand traps, primary and secondary settling tanks, aerotanks, oxspenks and other structures at a biological treatment plant Wastewater.

The main goals of automation of water disposal systems and facilities are to improve the quality of water disposal and wastewater treatment (uninterrupted discharge and pumping of wastewater, the quality of wastewater treatment, etc.); reduction of operating costs; improvement of working conditions.

The main function of systems and facilities for biological wastewater treatment is to increase the reliability of the facilities by monitoring the condition of the equipment and automatically checking the reliability of information and the stability of the facilities. All this contributes to the automatic stabilization of the parameters of technological processes and indicators of the quality of wastewater treatment, prompt response to disturbing influences (changes in the amount of wastewater discharged, changes in the quality of treated wastewater). Rapid detection contributes to the localization and elimination of accidents and malfunctions technological equipment. Ensuring the storage and operational processing of data and their presentation in the most informative form at all levels of management; data analysis and development of control actions and recommendations for 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

Within each system there are the following structures: functional, organizational, informational, software, technical.

The basis for creating a system is the functional structure, while the remaining structures are determined by the functional structure itself.

According to the functional feature, each control system is divided into three subsystems:

operational control and management of technological processes;

operational planning of technological processes;

· calculation of technical and economic indicators, analysis and planning of the work of the drainage system.

In addition, subsystems can be divided into hierarchical levels according to the criterion of efficiency (duration of functions). Groups of functions of the same type of the same level are combined into blocks.

Functional structure The automated control system for the treatment facilities is shown in Figure 1.

Fig.1 Functional structure of the automated control system for the operation of wastewater treatment plants

2 Supervisory control

The main technological processes controlled and managed by the dispatcher at biological wastewater treatment facilities are:

· unloading sand from sand traps and raw sediment from primary sedimentation tanks;

· stabilization of the pH value of the water entering the aerotanks at the optimum level;

Discharge of toxic wastewater into an emergency tank and its subsequent gradual supply to aerotanks;

Discharge of part of the water flow into the reservoir or pumping water from it;

distribution of waste water between parallel operating aerotanks;

· distribution of waste water along the length of the aeration tank for dynamic redistribution of the working volume between the oxidizer and the regenerator in order to accumulate sludge and improve the average daily quality of treated water;

air supply to maintain the optimal concentration of dissolved oxygen in the entire volume of the aerotank;

supply of returnable activated sludge to maintain a constant load on the sludge organic matter;

unloading of sludge from secondary settling tanks;

· removal of excess activated sludge from aerotanks to maintain its optimal age;

· turning on and off pumps and blowers to minimize energy consumption for pumping water, sludge, sludge and air.

In addition, the following signals are transmitted from controlled objects to control centers: emergency shutdown of equipment; violation of the technological process; limit levels of wastewater in tanks; limiting concentration of explosive gases in industrial premises; the limiting concentration of chlorine in the rooms of the chlorination room.

If possible, control rooms should be located near technological facilities (pumping stations, blower stations, laboratories, etc.), since control actions are issued to various electronic and pneumatic controllers or directly to actuators. Auxiliary premises (rest rooms, a bathroom, a storage room and a repair shop) will be provided in the control rooms.

3 Control of the operation of treatment facilities

Based on data technological control and process control predict wastewater schedule, quality and energy schedule to minimize total water treatment costs. The control and management of these processes is carried out with the help of a computer complex operating in the mode of either a dispatcher's adviser or automatic control.

Quality control of the process and optimized management of it can be ensured by measuring such parameters as the degree of toxicity of wastewater to activated sludge microorganisms, the intensity of biooxidation, BOD of incoming and treated water, sludge activity, and others that cannot be determined by direct measurement. These parameters can be determined by calculation based on the measurement of the oxygen consumption rate in small-volume process tanks with a special load mode. The rate of oxygen consumption is determined by the time of decrease in the concentration of dissolved oxygen from the maximum to the minimum set values when aeration is turned off or by a 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 process unit and a microprocessor controller that controls the meter units and calculates the oxygen consumption rate. The time of one measurement cycle is 10-20 minutes depending on the speed. The technological unit can be installed on the service bridge of the aerotank or aerobic stabilizer. The design ensures the operation of the meter outdoors in winter. The rate of oxygen consumption can be determined continuously in large volume reactors at DC. supply of activated sludge, waste water and air. The system is equipped with flat jet dispensers with a capacity of 0.5-2 and 1 hour. The simplicity of design and high water consumption ensure high measurement reliability in industrial conditions. The meters can be used for continuous monitoring of the organic load. Greater accuracy and sensitivity in measuring the rate of oxygen consumption is provided by manometric measurement systems equipped with sealed reactors, the pressure in which is maintained by the addition of oxygen. The source of oxygen is, as a rule, an electrolyzer controlled by a pulsed or continuous pressure stabilization system. The amount of oxygen supplied is a measure of the rate at which it is consumed. Meters of this type are designed for laboratory research and BOD measurement systems.

The main purpose of the ACS for air supply is to maintain the specified concentrations of dissolved oxygen in the entire volume of the aerotank. Stable operation of such systems can be ensured if the signal is used to control not only the oxygen meter, but also the wastewater flow rate or the rate of oxygen consumption in the aerotank core.

The regulation of aeration systems makes it possible to stabilize the technological mode of cleaning and reduce the average annual energy costs by 10-20%. The share 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 kWh/m.

Typical sludge release control systems maintain a predetermined level of sludge-water separation. The interface 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 interface level indicator. A higher quality of purified water can be obtained if a tracking level gauge of the sludge-water interface is used for regulation.

To stabilize the sludge regime not only of the sedimentation tanks, but also of the entire system of the aeration tank - the return sludge pumping station - the secondary sedimentation tank, it is necessary to maintain a given recirculation coefficient, that is, so that the flow rate of the discharged sludge is proportional to the flow rate of the incoming waste water. The level of standing sludge is measured to indirectly control the change in the sludge index or a malfunction of the sludge flow control system.

When regulating the discharge of excess sludge, it is necessary to calculate the amount of sludge accrued during the day in order to remove only accreted sludge from the system and stabilize the age of the sludge. This ensures high sludge quality and optimal bio-oxidation rate. Due to the lack of active sludge concentration meters, this problem can be solved with the help of oxygen consumption rate meters, because the rate of sludge growth and the rate of oxygen consumption are interrelated. The computing unit of the system integrates the amount of oxygen consumption and the amount of sludge removed and once a day corrects the specified flow rate of excess sludge. The system can be used for both continuous and periodic discharge of excess sludge.

In oxytanks, higher requirements are imposed on the quality of maintaining the oxygen regime due to the danger of sludge intoxication at high concentrations of dissolved oxygen and a sharp decrease in the cleaning rate at low concentrations. During the operation of oxytanks, it is necessary to control both the supply of oxygen and the discharge of exhaust gases. The supply of oxygen 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 oxygen concentration in the treated gas.

Bibliographic list

1. Voronov Yu.V., Yakovlev S.V. Water disposal and wastewater treatment / textbook for universities: - M .: Publishing house of the Association of Construction Universities, 2006 - 704s.

Introduction

Theoretical part

1.1 Fundamentals of the operation of wastewater treatment

2 Analysis of modern wastewater treatment methods

3 Analysis of the possibility of automation of wastewater treatment processes

4 Analysis of existing hardware (PLC logic programmable controllers) and software tools

5 Conclusions on the first chapter

2. Circuitry

2.1 Development of a block diagram of the water level for filling the tank

2.2 Development of a functional diagram

3 Regulatory body calculation

4 Determination of controller settings. Synthesis of ACS

5 Calculation of parameters of the built-in ADC

2.6 Conclusion on the second chapter

3. Software part

3.1 Development of an algorithm for the functioning of the ACS system in the CoDeSys environment

3.2 Program development in the CoDeSys environment

3 Development of an interface for visual display of measurement information

4 Conclusions on the third chapter

4. Organizational and economic part

4.1 Economic efficiency 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 on the fifth chapter

Conclusion

Bibliography

Introduction

At all times, human settlements and the placement of industrial facilities were realized in the immediate vicinity of fresh water bodies used for drinking, hygiene, agricultural and industrial purposes. In the process of human use of water, it changed its natural properties and in some cases became dangerous in sanitary terms. Subsequently, with the development of engineering equipment of cities and industrial facilities, it became necessary to arrange organized methods for diverting contaminated waste water flows through special hydraulic structures.

At present, the importance of fresh water as a natural raw material is constantly increasing. When used in everyday life and industry, water is contaminated with substances of mineral and organic origin. This water is called waste water.

Depending on the origin of wastewater, it may contain toxic substances and pathogens of various infectious diseases. Water management systems of cities and industrial enterprises are equipped with modern complexes of gravity and pressure pipelines and other special facilities that carry out the diversion, purification, neutralization and use of water and precipitation. Such complexes are called a drainage system. Drainage systems also provide drainage and purification of rain and melt water. The construction of drainage systems was determined by the need to ensure normal living conditions for the population of cities and towns and maintain a good state of the natural environment.

Industrial development and urban growth in Europe in the 19th century. They led to the construction of drainage channels. A strong impetus to the development of urban wastewater was the cholera epidemic in England in 1818. In subsequent years, in this country, through the efforts of the parliament, measures were taken to replace open channels with underground ones and approved the quality standards for wastewater discharged into water bodies, and organized biological treatment of domestic wastewater in irrigation fields.

In 1898, the first drainage system was put into operation in Moscow, which included gravity and pressure drainage networks, a pumping station and the Lublin irrigation fields. She became the ancestor of the largest Moscow sewage and wastewater treatment system in Europe.

Of particular importance is the development modern system disposal of domestic and industrial wastewater, providing a high degree of protection of the environment from pollution. The most significant results have been obtained in the development of new technological solutions for the efficient use of water in wastewater systems and industrial wastewater treatment.

The 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. Theoretical part

1 Fundamentals of the operation of wastewater treatment

Wastewater - any water and precipitation discharged into water bodies from the territories of industrial enterprises and populated areas through the sewerage system or by gravity, the properties of which have been degraded as a result of human activity.

Wastewater can be classified by source of origin into:

) Industrial (industrial) wastewater (formed in technological processes during production or mining) is discharged through an industrial or general sewerage system.

) Household (household and faecal) wastewater (formed in residential premises, as well as in household premises at work, for example, showers, toilets) is discharged through a domestic or combined sewerage system.

) Surface sewage (divided into rain and melt, that is, formed during the melting of snow, ice, hail), as a rule, is discharged through a storm sewer system. It may also be called "storm drains".

Industrial wastewater, unlike atmospheric and domestic wastewater, does not have a constant composition and can be divided according to:

) Composition of contaminants.

) Pollutant concentrations.

) Pollutant properties.

) acidity.

) Toxic effect and effect of pollutants on water bodies.

The main purpose of wastewater treatment is water supply. The water supply system (of a populated area or an industrial enterprise) must ensure the receipt of water from natural sources, its purification, if this is caused by the requirements of consumers, and supply to places of consumption.

Water supply scheme: 1 - water supply source, 2 - water intake facility, 3 - pumping station of the 1st lift, 4 - treatment facilities, 5 - clean water reservoir, 6 - pumping station of the 2nd lift, 7 - water conduits, 8 - water tower, 9 - water distribution network.

To perform these tasks, the following structures are usually included in the water supply system:

) Water intake facilities, with the help of which water is received from natural sources.

) Water-lifting structures, that is, pumping stations that supply water to places of its purification, storage or consumption.

) Facilities for water treatment.

) Conduits and water supply networks that serve to transport and supply water to places of its consumption.

) Towers and tanks that play the role of regulating and spare tanks in the water supply system.

1.2 Analysis of modern wastewater treatment methods

Modern methods of wastewater treatment can be divided into mechanical, physico-chemical and biochemical. In the process of wastewater treatment, sludge is formed, which is subjected to neutralization, disinfection, dehydration, drying, and subsequent disposal of sludge is possible. If, according to the conditions for the discharge of wastewater into a reservoir, a higher degree of treatment is required, then after the facilities for complete biological treatment of wastewater, facilities for deep treatment are arranged.

Mechanical wastewater treatment facilities are designed to retain undissolved impurities. These include gratings, sieves, sand traps, settling tanks and filters of various designs. Lattices and sieves are intended for detention of large pollution of an organic and mineral origin.

Sand traps are used to separate impurities of the mineral composition, mainly sand. Sedimentation tanks trap settling and floating sewage contaminants.

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 facilities are a preliminary stage before biological treatment. With mechanical treatment of urban wastewater, it is possible to retain up to 60% of undissolved contaminants.

Physical and chemical methods of urban wastewater treatment, taking into account technical and economic indicators, are used very rarely. These methods are mainly used to treat 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 wastewater treatment methods are based on the vital activity of microorganisms that 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 sand removal; 4 - primary sump; 5 - sludge output; 6 - biofilter; 7 - jet sprinkler; 8 - point of chlorination; 9 - secondary sump; 10 - release.

Mechanical wastewater treatment can be performed in two ways:

) The first method consists in straining water through grates and sieves, as a result of which solid particles are separated.

) The second method is to settling water in special sedimentation 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 - settling tanks; 5 - mixers; 6 - contact tank; 7 - release; 8 - crushers; 9 - sand platforms; 10 - digesters; 11 - chlorination; 12 - silt pads; 13 - garbage; 14 - pulp; 15 - sandy pulp; 16 - raw sediment; 17 - digested sludge; 18 - drainage water; 19 - chlorine water.

Wastewater from the sewer network first enters the grates or sieves, where they are filtered, and large components - rags, kitchen waste, paper, etc. - are kept. Detained by gratings and nets, large components are taken out for disinfection. Strained wastewater enters the sand traps, where impurities are retained mainly of mineral origin (sand, slag, coal, ash, etc.).

1.3 Analysis of the possibility of automation, wastewater treatment processes

The main goals of automation of systems and facilities for wastewater disposal are to improve the quality of water disposal and wastewater treatment (uninterrupted discharge and pumping of wastewater, the quality of wastewater treatment, etc.), reduce operating costs, and improve working conditions.

The main function of water disposal systems and structures is to increase the reliability of the structures by monitoring the condition of the equipment and automatically checking the reliability of information and the stability of the structures. All this contributes to the automatic stabilization of the parameters of technological processes and indicators of the quality of wastewater treatment, prompt response to disturbing influences (changes in the amount of wastewater discharged, changes in the quality of treated wastewater). The ultimate goal of automation is to increase the efficiency of management activities. The wastewater treatment plant management system has the following structures: functional; organizational; informational; software; technical.

The basis for creating a system is the functional structure, while the remaining structures are determined by the functional structure itself. According to the functional feature, each control system is divided into three subsystems:

operational control and management of technological processes;

operational planning of technological processes;

calculation of technical and economic indicators, analysis and planning of the work of the drainage system.

Figure 5 - Functional structure of the automated control system for wastewater treatment plants

To improve the efficiency of data transmission, communication with control rooms and management of wastewater, as well as wastewater treatment processes, it is possible to recommend replacing not always reliable system telephony to fiber optic. However, most of the processes automatic systems management of drainage networks, pumping stations and wastewater treatment plants will be carried out on a computer. This also applies to accounting, analysis, calculations of long-term planning and work, as well as the implementation required documents for reporting on the operation of all water disposal systems and facilities.

To ensure the uninterrupted operation of sewerage systems, on the basis of accounting and analysis of reporting, it is possible to carry out long-term planning, which, in the end, will increase the reliability of the entire complex.

1.4 Analysis of existing hardware (PLC programmable logic controllers) and software

Programmable logic controllers (PLCs) have been an integral part of plant automation and process control systems for decades. The range of applications in which PLCs are used is very wide. It could be like simple systems lighting control systems, and systems for monitoring the environmental situation at chemical plants. The central unit of the PLC is the controller, to which components are added to provide the required functionality, and which is programmed to perform a certain specific task.

Controllers are produced by both well-known electronics manufacturers, such as Siemens, Fujitsu or Motorola, as well as control electronics companies, such as Texas Instruments Inc. Naturally, all controllers differ not only in functionality, but also in the combination of price and quality. Since at the moment Siemens microcontrollers are the most common in Europe, they can be found both at production facilities and at laboratory stands, we will opt for a German manufacturer.

Figure 6 - Logic module "LOGO"

Scope: control of technological equipment (pumps, fans, compressors, presses) heating and ventilation systems, conveyor systems, control systems road traffic, control of switching equipment, etc.

Programming controllers "Siemens" - modules "LOGO! Basic" can be performed from the keyboard with information displayed on the built-in display.

Table 1 Specifications

Supply voltage/input voltage: nominal value~115 … 240 VFrequency alternating current~47 ... 63 Hz Power consumption at supply voltage ~3.6 ... 6.0 W / ~230 V Discrete inputs: Number of inputs: 8 Input voltage: low level, not over high, not less than 5 V 12 V not less than ~0.03 mA ~0.08 mA/=0.12 mADiscrete outputs: Number of outputs 4Galvanic isolationYesConnection of a discrete input as a loadPossibleAnalog inputs: Number of inputs 4 (I1 and I2, I7 and I8)Measuring range=0 … 10VMaximum input voltage=28.8VDegree of protection enclosures IP 20 Weight 190 g

The programming process of the "Siemens" controller comes down to programming the required functions and setting the settings (on/off delays, counter values, etc.). To perform all these operations, a system of built-in menus is used. The finished program can be rewritten into a memory module enclosed in the interface of the "LOGO!" module.

The microcontroller "LOGO!", German company "Siemens", is suitable for all technical parameters.

Consider domestic microcontrollers. Currently, there are not so many enterprises in Russia that are engaged in the production of microcontroller equipment. At the moment, a successful company specializing in the production of systems for automation of control is the company "OWEN", which has at its disposal production facilities in the Tula region. Since 1992, this company has been specializing in the production of microcontrollers and sensor equipment.

The leader of "OWEN" microcontrollers is a series of PLC logic controllers.

Figure 7 - Appearance of PLC-150

PLC-150 can be used in various areas - from the creation of control systems for small and medium-sized objects and ending with the construction of dispatching systems. Example Automation of the water supply system of a building using the OWEN PLC 150 controller and the OWEN MVU 8 output module.

Figure 8 - Scheme of building water supply using PLC 150

Consider the main technical parameters of the PLC-150. General information are given in the table.

Table 2 General information

Design Unified housing for mounting on a DIN rail (width 35 mm), length 105 mm (6U), terminal spacing 7.5 mm Degree of protection of the housing IP20 Supply voltage: PLC 150 & 22090 ... 264 V AC (nominal voltage 220 V) with a frequency of 47 ... 63 Hz Front panel indication 1 indicator power supply 6 status indicators of digital inputs 4 status indicators of outputs 1 indicator of the presence of communication with CoDeSys 1 indicator of the user program operation Power consumption 6 W

The resources of the PLC-150 logic controller are shown in Table 3.

Table 3 Resources

CPU 32&x bit RISC&200 MHz processor based on ARM9 core 9 RAM capacity 8 MB CoDeSys core program and archive non-volatile memory 4 MB Retain&memory size 4 kV PLC cycle execution time Minimum 250 µs (non-fixed), typical from 1 ms

Information about digital inputs is given in Table 4.

Table 4 Digital inputs

Number of digital inputs6Galvanic isolation of digital inputs, groupIsolation strength of digital inputs1.5 kVMaximum frequency of the signal applied to the digital input1 kHz with software processing 10 kHz with hardware counter and encoder processor

Information about analog inputs is given in table 5.

Table 5 Analog inputs

Number of analog inputs4Types of supported unified input signalsVoltage 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: TXK (L), TGK (J), TNN (N), TXA (K), TPP (S ), CCI (R), TPR (V), TVR (A&1), TVR (A&2) Built-in ADC capacity16 bitInternal resistance of the analog input: in current measurement mode in voltage measurement mode 0...10 V 50 Ohm about 10 kOhm analog input 0.5 sBasic reduced measurement error limit for analog inputs 0.5 % No galvanic isolation of analog inputs

PLC-150 programming is carried out using professional system programming CoDeSys v.2.3.6.1 and older. CoDeSys is a Controller Development System. The complex consists of two main parts: the CoDeSys programming environment and the CoDeSys SP execution system. CoDeSys runs on a computer and is used in the preparation of programs. Programs are compiled into fast machine code and downloaded to 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 manufacture equipment with CoDeSys. Thousands of people work with it every day, solving industrial automation problems. To date, CoDeSys is the most widespread IEC programming system in the world. In practice, it itself serves as a standard and model for IEC programming systems.

Synchronization of the PLC 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 in all respects. Both analog and digital measuring devices with unified signals can be connected to it. The controller is easily coordinated with a personal computer using the "COM" port, there is the possibility of remote access. It is possible to coordinate PLC-150 with programmable logic controllers from other manufacturers. The PLC-150 is programmed using the Controller Development System (CoDeSys), in a high-level programming language.

5 Conclusions on the first chapter

In this chapter, the fundamentals of the functioning of wastewater treatment, the analysis of modern methods of treatment and the possibility of automating these processes were considered.

An analysis was made of existing hardware (PLC logical programmable controllers) and software for managing process equipment in wastewater treatment. The analysis of domestic and foreign manufacturers of microcontrollers is made.

2. Circuitry

One of the important functions of automation is: automatic control and management of technological processes, equipment of pumping stations and treatment facilities, creation of automated workplaces for all specialties and profiles of work based on modern technologies.

Modern drainage networks and pumping stations should, if possible, be designed with management without the constant presence of maintenance personnel.

1 Development of a block diagram of the water level for filling the main reservoir

The block diagram of the automatic control system is shown in Figure 9:

Figure 9 - Block diagram

On the right side of the block diagram is the PLC-150. To the right of it is an interface for connecting to a local network (Ethernet) for remote access to the controller. The signal is transmitted digitally. Through the RS-232 interface, it is coordinated with a personal computer. Since the controller is not demanding on the technical component of the computer, even a weak "machine" like Pentium 4 or similar models will be enough for the correct operation of the entire system as a whole. The signal between the PLC-150 and the 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= 3 [m] - pipe height.

h 0= 1.0 [m] - set level.

Q n0 = 12000 [l/h]-nominal flow.

d = 1.4 [m] - pipe diameter.

Transfer function of the op amp:

(1)

Let's calculate the numerical values of the transfer function.

Tank section area:

(2)

Rated incoming flow:

(3)

Transfer coefficient 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 the ACS

Where: Кр.о. - the transfer coefficient of the regulatory body (RO) of the incoming flow Qpo;

Kd - transfer coefficient of the level sensor h

Wp - transfer function of the automatic controller

Calculation of the regulator gain K r.o :

where - change in the incoming flow;

change in the degree of opening of the valve (in percent).

The dependence of the incoming flow on the valve opening degree is shown in Figure 12:

Figure 12 - Dependence of the incoming flow on the degree of opening of the valve

Evaluation of the level sensor gain

The transfer coefficient of the level sensor is defined as the ratio of the increment of the output parameter of the level sensor i[mA] to input parameter [m].

The maximum height of the liquid level that the level sensor should measure corresponds to 1.5 meters, and the change in the current unified output signal of the level sensor when the level changes in the range of 0-1.5 meters corresponds to 4-20 [mA].

(7)

General industrial level sensors have a built-in function of smoothing the output signal by a first-order inertial filter-link with a set time constant Tf in the range from units to tens of seconds. We select the filter time constant Тf=10 s.

Then the transfer function of the level sensor is:

(8)

The structure of the control system will take the form:

Figure 13 - structure of the control system

Simplified control system structure with numerical values:

Figure 14 - simplified structure of the control system

Logarithmic amplitude-phase frequency characteristics of the unchanging part of the system

LAFC of the unchanging part of the ACS are constructed by an 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 = 56 s is the time constant, the LAFC has the form of a straight line parallel to the frequency axis at the level of 20 lg K = 20 lg0.43 = -7.3 dB, and for frequencies greater than 1 /T, the LAFC is a straight line with a slope of -20db/dec to a corner frequency of 1/Tf, where the slope changes by an additional -20db/dec to -40db/dec.

Corner frequencies:

(10)

(11)

Thus we have:

Figure 15 - LAFC of the original open-loop system

2.3 Calculation of the regulator for incoming and outgoing costs

Let's make a choice of a regulatory body based on the conditional capacity Cv.

The calculation of the value of Cv is carried out according to international standard DIN EN 60534 according to the following formula:

(12)

where Q - consumption [m 3/h], ρ - density of liquids [kg/m 3], Δ p - pressure difference [bar] before the valve (P1) and behind the valve (P2) in the direction of flow.

Then for the flow regulator Q n0 according to source data:

(13)

For a possible change in flow rate Qp in the process of automatic control relative to its nominal value Qp 0the maximum value of Qp is taken twice as much as the nominal value, that is .

The bore diameter for the incoming flow is calculated as follows:

(14)

Similarly, for the outgoing flow we have:

(15)

(16)

2.4 Determination of controller settings. Synthesis of ACS

The construction of the LAFC of an open-loop ACS is based on the consequence of the theory of linear systems, which is that if the LAFC of an open-loop system (consisting of minimum-phase links) has a slope of -20 dB / dec in the region of significant frequencies (the sector cut off by lines of ± 20 dB), then:

closed ACS is stable;

the transition function of a closed ACS is close to monotonic;

regulation time

. (17)

The structure of an open source system with a PI controller:

Figure 16 - Structure of the original system with a PI controller

Desired LACH (L well ) the simplest form of an open-loop automatic control system, which would satisfy the given quality indicators in closed form, should have a slope of the LAF equal to -20 dB / dec in the vicinity of significant frequencies and an intersection with the frequency axis at:

(18)

In the region of the low-frequency asymptote, to create a zero (according to TOR) static error δ st = 0 frequency characteristics of an open system must correspond to an integrator of at least 1st order. Then it is natural to form the desired LAFC in this region in the form of a straight line with a slope of -20 dB/dec. as a continuation of Lzh from the region of essential frequencies. In order to simplify the implementation of the ACS, the high-frequency asymptote must correspond to the high-frequency asymptote of the unchanging part of the system. Thus, the desired LAFC of an open system is shown in Figure 0:

Figure 17 - Desired LAFC of an open system

According to the accepted structure of the industrial ACS, the only means of bringing the LAFCH to the unchanging part of L LF to L well is a PI-controller with a transfer function LAFC (at K R =1)

Figure 18 - PI-regulator LAFC

Figure 14 shows that for in the low-frequency region, the LAFC of the PI controller corresponds to an integrating link with a negative phase shift of -90 degrees, and for the frequency characteristics of the controller correspond to an amplifying link with a zero phase shift in the region of significant frequencies of the designed system with an appropriate choice of the value T and .

We accept the controller integration constant equal to the time constant T of the control object, i.e. T and = 56, at K R =1. Then the LAFC of the open ACS will take the form L 1=L LF +L pi , qualitatively corresponding to the form L well in the figure, but with a lower gain. To match the LAFC of the designed system with L well it is necessary to increase the open-loop gain by 16 dB, i.e. 7 times. Therefore, the controller settings are defined.

Figure 19 - Synthesis of ACS. Defining controller settings

The same controller settings are obtained if from L well graphically subtract L LF and according to the type of LAFC of the resulting sequential 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 an open system has the form , which contains an integrating link. When constructing the LAFC corresponding to W p (p) gain K p 0,32/7850must numerically correspond to the frequency of intersection of the LAF with the axis ω at frequency With -1, where With -1 or K p =6,98.

With the calculated settings of the controller, the ACS is stable, has a transition function close to monotonic, the control time t R =56 s, static error δ st =0.

Sensor equipment

The 2TRM0 meter is designed to measure the temperature of heat carriers and various media in refrigeration equipment, drying cabinets, ovens for various purposes and other technological equipment, as well as to measure other physical parameters (weight, pressure, humidity, etc.).

Figure 20 - Meter 2TRM0

Accuracy class 0.5 (thermocouples)/0.25 (other signal types). The regulator is produced in 5 types of housings: wall-mounted H, mounting on Din-rail D and switchboard Sch1, Sch11, Sch2.

Figure 21 - Functional diagram of the device OWEN 2 TPM 0.

Figure 22 - Dimensional drawing of the measuring device

Device connection diagram:

The figure shows a diagram of the terminal block of the device. The figures show the connection diagrams of the device.

Figure 23 - Device connection diagram

Terminal block of the device.

The multi-channel power supply unit BP14 is designed to power sensors with a stabilized voltage of 24 V or 36 V with a unified output current signal.

The power supply unit BP14 is produced in a housing with mounting on a DIN rail type D4.

Figure 28 - Power supply

Main functions:

Converting AC (DC) voltage to stabilized DC in two or four independent channels;

Starting current limitation;

Overvoltage protection of impulse noise at the input;

Protection against overload, short circuit and overheating;

Indication of the presence of voltage at the output of each channel.

Figure 29 - Wiring diagram for a two-channel power supply unit BP14

Frequency of input alternating voltage 47...63 Hz. Current protection threshold (1.2...1.8) Imax. The total output power is 14W. The number of output channels is 2 or 4. The nominal output voltage of the channel is 24 or 36 V.

Figure 30 - Dimensional drawing of the power supply

Output voltage instability when the supply voltage changes ±0.2%. Output voltage instability when the load current changes from 0.1 Imax to Imax ±0.2%. Operating temperature range -20 ... +50 °C. Output temperature instability coefficient voltage in the operating temperature range ± 0.025% / ° C. Dielectric strength - input - output (effective value) 2 k.

SAU-M6 is a functional analogue of the ESP-50 and ROS 301 devices.

Figure 31 - Level indicator

Figure 32 - SAU-M6 connection diagram

Three-channel liquid level indicator OWEN SAU-M6 - 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 analogue of the ESP-50 and ROS 301 devices.

The device is available in a wall-mounted housing type H.

Functionality of the level switch

Three independent channels for monitoring the liquid level in the tank

Ability to invert the operating mode of any channel

Connection of various level sensors - conductometric, float

Work with liquids of different electrical conductivity: distilled, tap water, contaminated water, milk and food products(weakly acidic, alkaline, etc.)

Protection of conductometric sensors from salt deposition on electrodes by supplying them with alternating voltage

Figure 34 - Outline drawing

Specifications of the instrument Nominal supply voltage of the instrument is 220 V, frequency 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 - 3. The number of built-in output relays - 3. The maximum allowable current switched by the contacts of the built-in relay is 4 A at 220 V 50 Hz (cos > 0.4).

Figure 35 - Discrete I/O module

Discrete inputs and outputs module for distributed systems in RS-485 network (ARIES, Modbus, DCON protocols).

The module can be used in conjunction with programmable controllers OWEN PLC or other. MDVV operates in the RS-485 network if there is a "master" in it, while MDVV itself is not a "master" of the network.

discrete inputs for connecting contact sensors and transistor n-p-n keys type. Ability to use any discrete input (maximum signal frequency - 1 kHz)

Possibility to generate a PWM signal by any of the outputs

Automatic transfer of the actuator to emergency operation mode in case of network exchange failure

Support for common protocols Modbus (ASCII, RTU), DCON, ARIES.

Drawing - 36 General scheme connection of the MDVV device

Figure 37 - Functional diagram of MDVV

MEOF are designed to move the working bodies of shut-off and control pipeline valves of a rotary principle of operation (ball and plug valves, butterfly valves, dampers, etc.) in automatic control systems for technological processes in various industries in accordance with command signals coming from regulating or control devices . Mechanisms are installed directly on the armature.

Figure 38 - The device of the MEOF mechanism

Figure 39 - Dimensions

Scheme of installing the Metran 100-DG 1541 sensor when measuring hydrostatic pressure (level) in an open tank:

Figure 40 - Scheme of sensor installation

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 artificial sapphire wafer.

Figure 41 - Appearance of the device

A sensing element with a single-crystal structure of silicon on sapphire is the basis of all sensor blocks of sensors of the Metran family.

For better view liquid crystal indicator (LCD) and for ease of access to the two compartments of the electronic converter, the latter can be rotated relative to the measuring unit from the set position at an angle of no more than 90 ° counterclockwise.

Figure 42 - Scheme of the external electrical connection of the sensor:

Where X is a terminal block or connector;

Rн - load resistance or total resistance of all loads in the control system;

BP - DC power supply.

2.5 Calculation of parameters of the built-in ADC

Let's 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 , number of code bits n, resolution ∆ and conversion error.

The bit depth of the ADC is determined by the formula:

Log 2N, (19)

where N is the number of discrets (quantum levels);

Since the ADC is built into the selected PLC-150 controller, we have n=16. The resolution of the ADC is the input voltage corresponding to one in the least significant bit of the output code:

(20)

where 2 n - 1 - maximum weight of the input code,

in = U max - U min (21)

At U max = 10V, U min = 0V, n = 16,

(22)

The larger n, the smaller and the more accurately the output code can represent the input voltage.

Relative resolution value:

, (23)

where ∆ is the smallest distinguishable step of the input signal.

Thus, ∆ is the smallest distinguishable step of the input signal. The ADC will not register a signal of a lower level. 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 methodological quantization error ∆ δ To (discreteness) and instrumental error due to non-ideality of transducer elements. Quantization error ∆ To due to the very principle of representing a continuous signal by quantized levels spaced from each other by a selected interval. The width of this interval is the resolution of the converter. The largest 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 defined 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 least significant digit of the input code: Δ=U max /(2n -1), where 2 n -1 - maximum input code weight. At U max = 10B, n = 10 (digit capacity of the built-in DAC) we calculate the resolution of the DAC of the microcontroller:

(28)

The more n, the less Δ and the more precisely the output voltage can represent the input code. Relative value of DAC resolution:

(29

Figure 43 - Wiring diagram

Figure 44 - Wiring diagram

2.6 Conclusion on 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 controller settings and the synthesis of the ACS were made.

Parameters of the transfer function of the control object. Selected sensor equipment. The calculation of the parameters of the ADC and DAC built into the microcontroller OWEN PLC 150 was also made.

1 Development of an algorithm for the functioning of the SAC system in the CoDeSys environment

Professional development of industrial automation systems is inextricably linked with CoDeSys (Controller Development System). The main purpose of the CoDeSys complex is the development of application programs in the languages of the IEC 61131-3 standard.

The complex consists of two main parts: the CoDeSys programming environment and the CoDeSys SP execution system. CoDeSys runs on a computer and is used in the preparation of programs. Programs are compiled into fast machine code and downloaded to 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 manufacture equipment with CoDeSys. Thousands of people work with it every day, solving industrial automation problems.

Application Development software for PLC-150, as well as for many other controllers, is produced on a personal computer in the CoDeSys environment under Microsoft Windows. The code generator directly compiles the user program into machine codes, which ensures the highest performance of the controller. The execution and debugging system, code generator and function block libraries are specially adapted to the PLC series controller architecture.

Debugging tools include viewing and editing inputs/outputs and variables, executing the program in cycles, monitoring the execution of the program algorithm in a graphical representation, graphical tracing of variable values over time and events, graphical visualization and simulation of process equipment.

The main window of CoDeSys consists of the following elements (they are located from top to bottom in the window):

) Toolbar. It contains buttons for quick access to menu commands.

) An object organizer with POUs, Data types, Visualizations, and Resources tabs.

) Separator of the CoDeSys Object Organizer and Workspace.

) The workspace where the editor is located.

) Message window.

) A status bar containing information about the current state of the project.

The toolbar, message box, and status bar are optional elements of the main window.

The menu is located at the top of the main window. It contains all CoDeSys commands. The appearance of the window is shown in Figure 45.

Figure 45 - Window appearance

Buttons on the toolbar provide quicker access to menu commands.

A command called from a 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 over a toolbar button, after a short period of time you will see the name of that button in the tooltip.

The buttons on the toolbar are different for different CoDeSys editors. You can get information about 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 functioning algorithm in the CoDeSys environment is shown in Figure 48.

Figure 48 - Block diagram of functioning in the CoDeSys environment

As can be seen from the block diagram, after turning on the microcontroller, a program is loaded into it, variables are initialized, inputs are read, and 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 the output data is recorded and the packages are generated via serial interfaces. After that, the algorithm goes in cycles to read the inputs or the work ends.

2 Program development in the CoDeSys environment

We launch Codesys and create a new project in the ST language. The target file for ARM9 is already installed on the personal computer, it automatically selects the required library. Communication with the controller has been established.

reg_for_meof:VALVE_REG; (*Regulator for controlling PDZ*)

K,b:REAL; (*control curve factors*)

timer_for_valve1: TON; (*emergency stop timer*)

safety_valve_rs_manual: RS;(*for manual valve control*)

reference: REAL; (*setting the angle of rotation of the PDZ*)_VAR

(*when adjusting, we fix the signal from the MEOF position sensor and calculate the values ain low ain high, initially we assume that the sensor is 4-20 milliamps and at 4 mA - the PDZ is completely closed (0%), and at 20 ma - completely open (100%) - set in PLC configuration *)NOT auto_mode THEN (*if not automatic mode*)_open:=manual_more; (*open by pressing a button*)_close:=manual_less; (*close on button press*)

safety_valve_rs_manual(SET:=valve_open , RESET1:=valve_close , Q1=>safety_valve); (*emergency valve control*)

(*when adjusting, we fix the signal from the pressure sensor and calculate the values ain low ain high, initially we assume that the sensor is 4-20 milliamps and at 4 ma - the tank is empty (0%), and at 20 ma - full (100%) - 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> WORD_TO_REAL(w_reference1) THEN (*set the rotation angle - decrease in proportion to the increase in the "pressure sensor" level --- angle =K*level+b *)

K:=(-100/(WORD_TO_REAL(w_reference2-w_reference1)));

b:=100-K*(WORD_TO_REAL(w_reference1));

reference:=K*pressure_sensor+b;

(*timer for emergency damper control*)

timer_for_valve1(

IN:=(pressure_sensor> WORD_TO_REAL(w_reference2)) AND high_level_sensor ,

(*emergency valve opening condition*)

IF timer_for_valve1.Q

reference:=0; (*close MEOF*)

safety_valve:=TRUE; (*open emergency valve*)

safety_valve:=FALSE;

(*damper controller*)_for_meof(

IN_VAL:=reference ,

POS:=MEOF_position ,

DBF:=2 , (*controller sensitivity*)

ReversTime:=5 , (*no more than 600 turns*)

MORE=>MEOF_open ,

LESS=>MEOF_close ,

FeedBackError=>);_IF;

(*transformation of data for display in scud*)

w_MEOF_position:=REAL_TO_WORD(MEOF_position);_level:=REAL_TO_WORD (pressure_sensor);

(*mode indication for filling auto-manual buttons*)_out:=auto_mode;

(*indication of the output for filling the buttons close/open the emergency valve*)_out:=safety_valve;

3.3 Development of an interface for visual display of measurement information

The Trace Mode 6 program was chosen to develop the visual display interface, because it has all the functions and characteristics we need:

has a fairly wide range of possibilities for simulating technological processes on a graphic screen;

all standard programming languages for SCADA systems and controllers are available;

friendly graphical interface;

fairly simple connection to a programmable logic controller;

the full version of this system is available on the manufacturer's website. race Mode 6 is designed to automate industrial enterprises, energy facilities, smart buildings, transport facilities, energy metering systems, etc.

The scale of automation systems created in Trace Mode can be anything - from autonomously operating control controllers and operator workstations, to geographically distributed control systems, including dozens of controllers exchanging data using various communications - the local network, intranet/internet, serial buses based on RS-232/485, leased and dial-up telephone lines, radio channel and GSM networks.

The project's integrated development environment in the Trace Mode program is shown in Figure 49.

Figure 49 - Integrated Development Environment Trace Mode 6

The project navigator allows you to quickly navigate between project sub-items. When you hover over one of the items, a comment appears that allows you to understand the content.

Figure 50 - Project Navigator

The mnemonic 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 the control mode, the ability to adjust dampers);

Display of the angle of rotation of the PDZ;

Indication of the water level in the tank;

Emergency reset (in case of overflow of water in the tank);

Measurement information tracking graph (water level status and damper position are displayed on the graph).

Figure 51 - Mnemonic diagram of the storage tank

The actual damper rotation angle (0-100%) is displayed under the "PDZ Position" field, which allows you to more accurately track the measurement information.

Figure 52 - Position of the PDZ

The arrows to the left of the tank change color from gray to green when the PLC exits are triggered (signal from the ACS), i.e. If the arrow is green, then the water level is higher than the sensor.

The slider on the scale is the level indicator (according to the meter pressure sensor) (0-100%).

Figure 53 - Level indicator

Management can be carried out in two modes:

) Automatic.

When a mode is selected, the color of the corresponding button changes from gray to green and that mode becomes active for use.

The "Open" and "Close" buttons are used to control the valves in manual mode.

V automatic mode it is possible to set tasks, on which the angle of rotation of the PDZ will depend.

To the right of the "task 1" field, the level in the tank is entered, at which the angle of rotation of the PDZ will begin to decrease.

To the right of the "task 2" field, the level in the tank is entered at which the PDZ will be completely closed.

An emergency valve also works in automatic mode in case of a possible overflow of water. The emergency valve opens when the level is exceeded above "task 2" and when the upper level sensor (ACS) is triggered for 10 seconds.

Figure 54 - Emergency reset

For easy tracking of 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 line shows the damper position.

Figure 55 - Graph of the level and position of the damper

4 Conclusions on the third chapter

In the third chapter, the development of an algorithm for the functioning of the system in the CoDeSys environment was carried out, a block diagram of the functioning of the system was built, and a software module for input / output of information in the process control system was developed.

An interface for visual display of measurement information was also developed using trace programs Mode 6, for automatic control system.

4. Organizational - economic part

1 Economic efficiency of process control systems

Economic efficiency - the effectiveness of the economic system, expressed in relation to the useful final results of its functioning to the resources expended.

Production efficiency is the sum of the efficiency of all operating enterprises. The efficiency 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 with minimal cost and sell these products at the lowest cost. The economic efficiency of the enterprise, in contrast to its technical efficiency depends on how its products meet the requirements of the market, the needs of consumers.

Automated process control systems provide an increase in production efficiency by increasing labor productivity, increasing production volume, improving the quality of products, rational use of fixed assets, materials and raw materials and reducing the number of employees at the enterprise. The implementation of the CS differs from the usual work on the implementation new technology the fact that it allows you to transfer the production process to a qualitatively new stage of development, characterized by a higher organization (orderliness) of production.

The 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 complex methods and algorithms to develop control decisions than those used before the introduction of the process control system.

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 the process control system, i.e., it may be different for different enterprises.

The justification for the development (or implementation) of new technology begins with a technical assessment by comparing the designed structure with the best of the existing domestic and foreign samples. High economic efficiency A new instrument or device is achieved by laying in its project progressive technical solutions. They can be expressed by a system of technical and operational indicators characterizing this species device. Progressive technical indicators are the basis for achieving high economic efficiency - the final criterion for evaluating new technology. This does not detract from the importance of technical indicators in assessing economic efficiency.

Usually economic indicators The effectiveness of new technology is few and the same for all industries, and technical indicators are specific to each industry and their number can be very large in order to comprehensively characterize the technical parameters of products. Technical indicators reveal to what extent a new device satisfies the need for output or work, and also 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 being created (implemented), study the technological process in which it will be used, and get a clear idea of the scope of work to be performed by the new product. All this should be reflected in the technical evaluation of the new machine (device) product.

Evaluation 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 result-cost approach does not always aim them at achieving high final performance results, finding internal reserves, and in fact does not contribute to improving overall efficiency.

2 Calculation of the main costs of the control system

When determining the economic efficiency of the introduction of mechanization and automation means, answers to the following questions should be obtained:

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 from the introduction into production.

The main costs for the creation of the control system consist, as a rule, of the costs for pre-project and design work Sn and the costs Sb for the purchase of special equipment installed in the control system. At the same time, the cost design work include, in addition to the costs associated with the development of the project, the costs of developing software and implementing the CS, and in the cost of equipment - in addition to the cost of the management computer science, 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 bears the costs of its operation. Thus, the annual costs of CS:

(30)

where T is the operating time; usually T = 5 - 7 years; - annual operating costs, rub.

Operating costs for CS:

(31)

where - annual fund wages personnel serving the control system, rub.; - depreciation and payment for funds, rub.; - expenses for public Utilities(electricity, water, etc.), rub.; - annual costs for materials and components, rub.

Depreciation charges and fees for funds:

(32)

where - cost of equipment of the i-th type, rub.; - coefficient of depreciation for the i-th type of equipment; - coefficient of deductions for funds.

Annual payroll for personnel serving the SU:

(33)

where - operating time of maintenance personnel per year, h; - average hourly rate of service personnel, rub.; - coefficient of shop overheads; m′ - the number of personnel serving the control system and specialized devices of technological equipment of personnel, people.

The cost estimate for the management system includes the following items of expenditure:

the cost of basic equipment;

the cost of additional equipment;

workers' wages;

deductions for social needs;

cost of machine time;

overheads.

The basic salary of Sosn performers, rubles, is determined by the formula:

WITH main = T oh *t With * b, (34)

where tс is the length of the working day, h (tс \u003d 8 h); - the cost of 1 person-hour (determined by dividing the monthly salary by the number of hours to be worked out per month), rub-hour.

The average cost of 1 person-hour is 75 rubles

The labor intensity of the work is 30.8 man-days.

WITH main \u003d 30.8 * 8 * 75 \u003d 18480 rubles. (35)

Additional salary Sdop, rub, is accepted in the amount of 15% of the basic salary.

Sdop \u003d 0.15 * 18 480 \u003d 2772 rubles.

Social contributions Sotch, RUB, are calculated from the sum of the basic and additional wages in the amount of 26.2%

WITH otch \u003d 0.262 * (C main + C additional ), (36)

Sotch \u003d 0.262 * (18480 + 2772) \u003d 5568 rubles.

Material costs Cm are:

C1 - the cost of the PLC-150 Microcontroller (average cost is 10,000 rubles);

C2 - the cost of the power supply (the average cost is 1800 rubles);

C3 - the cost of sensor equipment (average cost is 4000 rubles);

C4 - cost of a PC (average cost of a PC is 15,000 rubles, Pentium DC E6700, GA-EG41MFT-US2H, 2 x 2GB, 500Gb);

С5 - other expenses ( Consumables, wires, fasteners, etc.);

Cm = C1 + C2 + C3 + C4 + C5

C1 \u003d 10000 rubles.

C2 \u003d 1800 rubles.

C3 \u003d 4000 rubles.

C4 = 15,000 rubles.

C5 \u003d 9000 rubles.

Cm \u003d 10000 + 1800 + 4000 + 15000 + 9000 \u003d 39800 rubles.

Machine time is the period during which a machine (unit, machine tool, etc.) performs work on processing or moving a product without direct human impact on it.

The cost of machine time is determined by the formula:

WITH mv = T mash * C martyr , (37)

where Tmash - time of use of technical means, h;

Tsmch - the cost of a machine hour, which includes the depreciation of technical equipment, the cost of maintenance and repair, the cost of electricity, rub.

The time of using technical means is equal to the labor intensity of the work of the performers and is 412 hours.

The cost of a machine hour Tsmch is 17 rubles.

Smv \u003d 412 * 17 \u003d 7004 rubles.

Snack's overhead includes all costs associated with management and housekeeping. There are no such costs in this case.

The cost estimate for the development of an automated enterprise system is presented in table 0.

Table 6 - Development costs

Expense itemAmount, rub.Percentage of the total Costs of materials39800 54.2Basic salary1848025.1Additional salary27723.7Deductions for social needs55687.5Cost of machine time70049.5Total73624100

Thus, the costs for the control system amount to 73,624 rubles.

Figure 56 - Main costs for the control system

3 Organization of production processes

The 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 service processes. One of the main aspects of the formation of the production structure is to ensure the interconnected functioning of all components production process: preparatory operations, main production processes, Maintenance. It is necessary to comprehensively justify the most rational for specific production and technical conditions organizational forms and methods for the implementation of certain processes.

The principles of the 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 by the principle of combination, which means the unification of all or part of the diverse processes for the manufacture of certain types of products within the same area, 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, section) or dispersed over several units.

The principle of concentration means the concentration of certain production operations for the manufacture of technologically homogeneous products or the performance of functionally homogeneous work in separate workplaces, sections, workshops or production facilities of the enterprise. The expediency of concentrating homogeneous work in separate areas of production is due to the following factors: commonality technological methods, causing the need to use the same type of equipment; equipment capabilities, such as machining centers; an increase in output certain types products; the economic feasibility of concentrating the production of certain types of products or performing similar work.

The principle of proportionality lies in the natural combination of individual elements of the production process, which is expressed in a certain quantitative ratio of them to each other. Thus, proportionality in terms of production capacity implies equality in the capacities of sections or equipment load factors. In this case, the throughput of the procurement workshops corresponds to the need for blanks. machine shops, and the throughput of these shops - the needs of the assembly shop in the necessary parts. This implies the requirement to have in each workshop equipment, space, labor force 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 on the fifth chapter

In this chapter, in accordance with the assignment for the graduation project, the economic efficiency of the implementation of the process control system was determined. The main provisions were also considered and the calculation of the main costs for the control system was made.

5. Life safety and environmental protection

1 Life safety

When creating complex automated control systems, system design is increasingly being practiced, in the early stages of which questions of workplace safety and ergonomics are raised, fraught with large reserves for improving 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 at the workplace. The main objective of safety measures is to protect human health from harmful factors, such as electric shock, insufficient lighting, elevated level noise at the workplace, high or low air temperature in the working area, high or low air humidity, high or low air mobility. All this is achieved as a result of carrying out and implementing a complex of procedures and activities interconnected in meaning, logic and sequence, carried out during the development of the man-machine system and during its operation. The theme of the graduation project - " Automated system management of the wastewater treatment process after a car wash with the development of a software module for the OWEN microcontroller. Due to the specifics of this workplace, the company carries out wastewater treatment using chlorine, and chlorine is classified as an emergency chemically hazardous substance (AHOV).

Therefore, in order to ensure the safety of health and high labor productivity, it is necessary to investigate dangerous and harmful factors when working at an enterprise with the likelihood of hazardous emissions.

Dangerous and harmful factors when working with hazardous chemicals

Poisoning by emergency chemically hazardous substances (AHOV) during accidents and catastrophes occurs when AHOV enters the body through the respiratory and digestive organs, skin and mucous membranes. The nature and severity of 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 object (territory) and the duration of human exposure.

The above factors will also determine the clinical manifestations of lesions, which in the initial period may be:

) manifestations of irritation - cough, sore throat and sore throat, lacrimation and pain in the eyes, chest pain, headache;

) the growth and development of phenomena from the central nervous system (CNS) - headache, dizziness, feeling of intoxication and fear, nausea, vomiting, a state of euphoria, impaired coordination of movements, drowsiness, general lethargy, apathy, etc.

Protection from dangerous and harmful factors

To prevent the release of chlorine, the company must strictly observe the safety rules, instruct when handling hazardous chemicals, and control the admission of hazardous substances.

The company must have protective equipment in case of emergency. One of these means of protection is the GP-7 gas mask. The gas mask is designed to protect the respiratory organs, eyesight and face of a person from toxic substances, biological aerosols and radioactive dust (OV, BA and RP).

Figure 57 - Gas mask GP-7

Gas mask GP-7: 1 - front part; 2 - filtering-absorbing box; 3 - knitted cover; 4 - inhalation valve assembly; 5 - intercom (membrane); 6 - expiratory valve assembly; 7 - obturator; 8 - headband (occipital plate); 9 - frontal strap; 10 - temporal straps; 11 - cheek straps; 12 - buckles; 13 - bag.

Gas mask GP-7 is one of the latest and most advanced models of gas masks for the population. Provides highly effective protection against vapors of toxic, 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. Thanks to this, people over 60 years of age and patients with pulmonary and cardiovascular diseases can use it.

Figure 58 - GP-7 protective action time

Figure 59 - Specifications GP-7

Actions in the event of a chlorine accident

When receiving information about an accident with hazardous chemicals, put on respiratory protection, skin protection (cloak, cape), leave the accident area in the direction indicated in the radio (television) message.

Leave the zone of chemical contamination should be in the direction perpendicular to the direction of the wind. At the same time, avoid crossing tunnels, ravines and hollows - in low places, the concentration of chlorine is higher.

If it is impossible to leave the danger zone, stay indoors and perform emergency sealing: tightly close windows, doors, ventilation openings, chimneys, seal cracks in windows and at the joints of frames and go up to the upper floors of the building.

Figure 60 - Scheme of evacuation from the infection zone

After leaving the danger zone, take off your outer clothing, leave it outside, take a shower, rinse your eyes and nasopharynx. If signs of poisoning appear: rest, warm drink, consult a doctor.

Signs of chlorine poisoning: severe chest pain, dry cough, vomiting, pain in the eyes, lacrimation, impaired coordination of movements.

Personal protective equipment: gas masks of all types, gauze bandage 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 restricts breathing, drink plenty of 2% soda solution, wash the eyes, stomach, nose with the same solution, into the eyes - 30% albucid solution. 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 life human body, his performance and general well-being. Not without reason, so much attention is paid to the environment and, in particular, the problem of clean water.

In our time of developed technological progress, the environment is becoming more and more polluted. Waste water pollution by industrial enterprises is especially dangerous.

The most widespread wastewater pollutants are oil products - an unidentified group of hydrocarbons of oil, fuel oil, kerosene, oils and their impurities, which, due to their high toxicity, are, according to UNESCO, among the ten most dangerous environmental pollutants. Oil products can be in solutions in emulsified, dissolved form and form a floating layer on the surface.

Factors of wastewater pollution by oil products

One of the environmental pollutants is oily wastewater. They form in all technological stages extraction and use of oil.

The general direction of solving the problem of preventing environmental pollution is the creation of waste-free, low-waste, non-drainage and low-drainage industries. In this regard, when accepting, storing, transporting and issuing petroleum products to consumers, all necessary measures must be taken to prevent or reduce their losses to the maximum extent possible. This task should be solved by improving the technical means and technological methods for processing oil and oil products at oil depots and pumping stations. Along with this, local collection devices for various purposes can play a useful role, allowing you to collect spills or leaks of products in a pure form, preventing their removal with water.

With limited possibilities for using the above-mentioned funds, oil depots generate wastewater contaminated with oil products. In accordance with the requirements of existing normative documents they are subject to a fairly deep cleaning. The technology of purification of oil-containing waters is determined by the phase-dispersed state of the formed oil product - water system. The behavior of petroleum products in water is due, as a rule, to their lower density compared to the density of water and extremely low solubility in water, which is close to zero for heavy grades. In this regard, the main methods of water purification from oil products are mechanical and physico-chemical. Of the mechanical methods, settling has found the greatest use, and to a lesser extent, filtration and centrifugation. Of the physical and chemical methods, flotation attracts serious attention, which is sometimes referred to as mechanical methods.

Wastewater treatment from oil products by settling tanks and sand traps

Sand traps are designed to separate 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 facilities 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 a rectilinear or circular movement of water, vertical, in which the liquid moves vertically upwards, and sand traps with a screw (translational-rotational) movement of water. The latter, depending on the method of creating a helical movement, are divided into tangential and aerated.

The simplest horizontal sand traps are tanks with a triangular or trapezoidal cross section. The depth of sand traps is 0.25-1 m. The speed of water movement in them does not exceed 0.3 m/s. Sand traps with circular movement of water are made in the form of a round tank of conical shape with a peripheral tray for the flow of waste water. The sludge is collected in a conical bottom, from where it is sent for processing or dumping. They are used at flow rates up to 7000 m3/day. Vertical sand traps have a rectangular or round shape, in which wastewater moves with a vertical updraft 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 tank farms, 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.

Settling is the simplest and most commonly used method of separating coarsely dispersed impurities from wastewater, which, under the action of gravitational force, settle at the bottom of the sump or float on its surface.

Oil transport enterprises (oil depots, oil pumping stations) are equipped with various settling tanks to collect and purify water from oil and oil products. For this purpose, standard steel or reinforced concrete tanks are usually used, which can operate in the mode of a storage tank, settling tank or buffer tank, depending on the technological scheme of wastewater treatment.

Based on the technological process, the polluted waters of tank farms and oil pumping stations are unevenly supplied to the treatment facilities. For a more uniform supply of contaminated water to the treatment plant, buffer tanks are used, which are equipped with water distribution and oil gathering devices, pipes for supplying and discharging waste water and oil, a level gauge, breathing equipment, etc. Since oil is in water 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. To do this, two or more buffer tanks are installed in the scheme of treatment facilities, which operate periodically: filling, settling, pumping out. The volume of the reservoir is chosen based on the time of filling, pumping out and settling, and the settling time is taken from 6 to 24 hours. water.

Before pumping out the settled water from the tank, the oil that has surfaced and the precipitate that has fallen out are first removed, after which the clarified water is pumped out. To remove sediment at the bottom of the tank, drainage from perforated pipes is arranged.

A distinctive feature of dynamic sedimentation tanks is the separation of impurities in the water during the movement of the liquid.

In dynamic settling tanks or continuous settling tanks, the liquid moves in a horizontal or vertical direction, hence the settling tanks are divided into vertical and horizontal.

The vertical settling tank is a cylindrical or square (in terms of) tank with a conical bottom for easy collection and pumping of the settling sludge. The movement of water in a vertical sump occurs from the bottom up (for settling 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. sump. Floated impurities are removed using scrapers and transverse trays installed at a certain level.

Depending on the product being caught, horizontal settling tanks are divided into sand traps, oil traps, fuel oil traps, fuel traps, grease traps, etc. Some types of oil traps are shown in Figure 0.

Figure 61 - Oil traps

In radial clarifiers of round shape, water moves from the center to the periphery or vice versa. Large-capacity radial settling tanks used for wastewater treatment have a diameter of up to 100 m and a depth of up to 5 m.

Radial settling tanks with a central wastewater inlet have increased inlet rates, which leads to less efficient use of a significant part of the volume of the settling tank in relation to radial settling tanks with a peripheral sewage inlet and treated water withdrawal in the center.

The greater the height of the sump, the more time is needed for the particle to float to the surface of the water. And this, in turn, is associated with an increase in the length of the sump. Consequently, it is difficult to intensify the settling process in conventional oil traps. With an increase in the size of the settling tanks, the hydrodynamic characteristics of settling deteriorate. How thinner layer liquid, the process of ascent (settlement) occurs faster, all other things being equal. This situation has led to the creation of thin-layer settling tanks, which can be divided into tubular and plate-type ones according to their design.

The working element of the tubular settler 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 the pollution and the hydrodynamic parameters of the flow. Tubular sedimentation tanks are used with a small (10) and large (up to 60) pipe slope.

Settling tanks with a small slope of the pipe operate on a periodic cycle: clarification of water and flushing of tubes. It is expedient to use these settling tanks for clarification of wastewater with a small amount of mechanical impurities. The efficiency of clarification is 80-85%.

In steeply inclined tubular settlers, the arrangement of the tubes causes sediment to slide down the tubes, and therefore there is no need to flush them.

The operation time of the settling tanks practically does not depend on the diameter of the tubes, but increases with the increase in their length.

Standard tubular blocks are made of polyvinyl or polystyrene plastic. Typically, blocks are used about 3 m long, 0.75 m wide and 0.5 m high. The size of the tubular element in cross section is 5x5 cm. The designs of these blocks allow you to mount sections from them for any capacity; sections or individual blocks can easily be installed in vertical or horizontal clarifiers.

Plate settlers consist of a series of parallel plates, between which the liquid moves. Depending on the direction of water movement and the 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 widely used plate counterflow sedimentation tanks.

Figure 62 - Sumps

The advantages of tubular and plate settling tanks are their cost-effectiveness due to the small building volume, the possibility of using plastics that are lighter than metal and do not corrode in aggressive environments.

A common disadvantage of thin-layer settling tanks is the need to create a container for the preliminary separation of easily separable oil particles and large clots of oil, scale, sand, etc. The 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 liquid flow rate will increase in the rest. This situation will lead to a deterioration in the performance of the sump. Schematic diagrams of sedimentation tanks are shown in Figure 0.

5.3 Conclusions on the fifth chapter

In this section, the main issues of life safety and environmental protection were considered. An analysis of dangerous and harmful production factors. The development of protective measures for the release of chlorine was also carried out. In addition, in this chapter, the main tasks of protecting the environment were considered, and the installation of a horizontal sedimentation tank was proposed to treat wastewater from oil products.

Conclusion

In this graduation project, a software part was developed for an automatic control system for wastewater treatment after a car wash.

The basics of functioning and modern ways wastewater treatment. As well as the possibility of automating these processes. An analysis was made of existing hardware (logical programmable PLC controllers) and software for control systems.

The hardware part of the control system for controlling the process of car wash wastewater treatment has been developed.

An algorithm for the functioning of the system in the CoDeSys environment has been developed. A visual display interface has been developed in the Trace Mode 6 environment.

Bibliography

automation wastewater treatment

1. Lectures on the courses "Electronics" and "Technical measurements and devices". Kharitonov V.I.

2."Management technical systems"Kharitonov V.I., Bunko E.B., K.I. Mesha, E.G. Murachev.

3. "Electronics" Savelov N.S., Lachin V.I.

Technical documentation for car wash 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 of 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 MSTU MAMI, 2008. - 22p.

Technical documentation of MGUP "Mosvodokanal"

Stakhov - Purification of oily wastewater from enterprises for the storage and transport of petroleum products - 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 wastewater from industrial enterprises. The method includes neutralizing wastewater by supplying either an acid solution or an alkali solution to achieve a given pH value. An acid solution or an alkali solution is fed into the industrial effluent storage tank. Effluent, depending on their concentration, enters either an electrocoagulator or a galvanic coagulator for purification. The regulation of the quality of cleaning in the electrocoagulator is carried out by regulating the current depending on the electrical conductivity of the effluents. After that, the sedimentation process is carried out by flowing effluents from the sump to the sump using electric valves. To speed up the settling process, polyacrylamide is fed in, the undissolved precipitate is passed through salt and fine filters, then dehydrated, and clean effluents enter the electroplating line. This method improves the quality of industrial wastewater treatment for the use of the latter in the reverse cycle. 1 ill.

The invention relates to the field of automation of wastewater treatment processes, in particular for the treatment of wastewater from industrial enterprises. A method is known for automatically controlling the coagulation process by simultaneously controlling the flow rate of acid and coagulant into the reactor and controlling the color of the water, while at the same time the flow rate of the coagulant is regulated depending on the color of the water at at the outlet of the reactor and acid consumption depending on the pH value of the water at the outlet of the reactor (SU 1655830 A1, 06/15/1991). However, this method does not achieve complete precipitation of ions, which reduces the quality of purification. pH of the purified water, regulation of the flow rate into the apparatus, while measuring the redox potential of the purified water, forming a signal for setting the regulator, comparing it with the set value of the product, as a result of which a mismatch signal is generated and regulation is carried out the flow rate of industrial effluents using a regulator through a treatment apparatus depending on the magnitude of the mismatch of the experimentally established dependence (RU 2071951 C1, 01/20/1997). The disadvantage of this method is the low quality of industrial effluent treatment, the impossibility of using them in the reverse cycle. when implementing this invention, is to improve the quality of industrial wastewater treatment for the use of the latter in the reverse cycle. The technical result is achieved by the fact that in the method of automatic control of the wastewater treatment process of industrial enterprises, including the neutralization of wastewater by supplying either an acid solution or an alkali solution to achieve a predetermined value pH, according to the invention, an acid solution or an alkali solution is fed into the industrial effluent storage tank, then, depending on their concentration, the effluent enters either an electrocoagulator or a galvanic coagulator for purification, and the regulation the quality of cleaning in the electrocoagulator is carried out by regulating the current depending on the electrical conductivity of the effluents, after which the sedimentation process is carried out by flowing effluents from the sump to the sump using electric valves, polyacrylamide is supplied to accelerate the deposition process, the undissolved precipitate is passed through salt purification filters and fine filters, then they are dehydrated, and clean effluents enter the electroplating line. Comparison of the claimed invention with the known ones shows that the use of existing automation methods does not allow wastewater treatment from heavy metal ions, which makes it impossible to introduce treated effluents into the enterprise’s circulation cycle, while in the claimed The invention is a complete purification of industrial wastewater, which is carried out stepwise under the control of various sensors, allowing at the first stage to neutralize wastewater, then, depending on the concentration of wastewater, subject them to electrocoagulation ation or galvanic coagulation, while adjusting the quality of cleaning with an alternating electric current by supplying a saline solution, dehydrating the sediment with its subsequent use, for example, in galvanic production, and using the separated water in circulating water supply. Presented in the drawing, the automation scheme for industrial wastewater treatment includes: a wastewater storage tank 1, a level sensor 2, a level indicator 3, an acid dosing tank 4, an electric valve 5, an alkali dosing tank 6, an electric valve 7, a wastewater supply pump 8, an electrocoagulator 9 , galvanic coagulator 10, electric valve 11, salt solvent 12, electric blocker 13, settling tanks 14, polyacrylamide dosing tank 15, electric valve 16, treated wastewater tank 17, salt filter 18, fine filter 19, treated wastewater supply pump 20, electric valve 21, sludge dewatering processor 22, pH meter sensor 23, regulating pH meter 24, DC ammeter 25 of the rectifier unit of the electrocoagulator, regulating ammeter 26, electrodes 27, regulating ohmmeter 28, level sensor 29, level indicator 30. The method is implemented as follows .Industrial effluents, such as galvanic shop effluents, are fed into the effluent storage 1. When the setpoint is reached th upper level in the wastewater storage tank 1, the level sensor 2 sends an impulse to the level signaling device 3, which in turn gives a command to prepare the wastewater for treatment with a given pH value. To do this, either an acid solution from the dosing tank 4 is automatically supplied to the wastewater storage tank 1 by means of an electric valve 5, or an alkali solution from the bladder tank 6 using an electric valve 7. After reaching the set pH in the wastewater storage tank 1, which is recorded using a pH- 23 meters with a regulating pH meter 24, a regulating pH meter 24 gives a command to turn on the wastewater supply pump 8. Depending on the concentration of wastewater, the latter are fed either to the electrocoagulator 9 (at high concentration) or to the galvanic coagulator 10 (at medium or low concentrations ), where wastewater treatment takes place. The regulation of the quality of wastewater treatment in the electrocoagulator is carried out by regulating the current in the electrocoagulator by supplying a salt solution from the salt solvent 12 to the wastewater storage tank 1, by means of an electric valve 11 controlled by a regulating ammeter 26 connected to the output of the DC ammeter 25 of the rectifier unit of the electrocoagulator, in order to change the electrical conductivity of the effluents, supplied to the electrocoagulator 9. If during the cleaning process the value of the electric current in the electrocoagulator 9 falls below 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 wastewater treatment in the galvanic coagulator is controlled by regulating the supply of wastewater to the galvanic coagulator using the electric valve 21 depending on the concentration of wastewater. Control and regulation of the concentration of effluents in the drive 1 is carried out using a sensor 27 and a regulating ohmmeter 28. To prevent the discharge of untreated effluents from the electrocoagulator 9 in emergency situations(for example, clogging of the pipeline when the salt solution is supplied to the sewage accumulator 1) the electrical interlock 13 is turned on. panel, the supply of effluents is stopped. Purified effluents from the electrocoagulator 9 and galvanic coagulator 10 flow by gravity into the first sump 14, where undissolved sediment settles. To speed up the sedimentation process, polyacrylamide is automatically fed into the first sedimentation tank 14 from the bladder tank 15 by means of an electronic valve 16. For a more complete sedimentation of the undissolved sediment, the 2nd and undissolved sediment. After the sedimentation process in the settling tank system, the effluents flow by gravity into the treated effluent tank 17. Levels in the treated effluent tank 17 are signaled using level sensors 29 by the level indicator 30. When the drains of the sensor 29 reach the upper level in the treated effluent tank 17, the pump 20 is automatically switched on, which supplies wastewater to the salt purification filter 18, and then to the fine filter 19, from where clean wastewater enters the electroplating lines or technological schemes of other industries.

Claim

A method for automatically controlling the process of treating wastewater from industrial enterprises, which includes neutralizing wastewater 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 wastewater accumulator, then the wastewater, depending on their concentration, either into an electrocoagulator, or into a galvanic coagulator for cleaning, and the quality of cleaning in the electrocoagulator is regulated by regulating the current depending on the electrical conductivity of the effluents, after which the sedimentation process is carried out by flowing effluents from the sump to the sump using electric valves, polyacrylamide, undissolved sediment is fed to accelerate the deposition process pass through salt and fine filters, then dehydrate, and clean effluent enters the electroplating line.

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