Liquid fuel and its characteristic. Organic fuel Main types of fuels and their classification

The main definitions, classification and origin of organic fuel. Elemental and technical composition of fuel. Heat combustion fuel and ways to determine it. Solid fuel. Liquid fuel. Gaseous fuel. Conditional fuel.

The fuel is called substances that can enter with oxygen in the air in a fastened oxidative process - burning, highlighting a significant amount of heat. The fuel is a complex organic compound that are included in its composition of combustible elements smelted by non-combustible constituents that have a significant impact on its quality.

Its main types are organic fuels: peat, combustible shale, coals, natural gas, oil refining products.

By method of obtaining distinguish natural and artificial fuels. TO

natural includes natural fuels: coal, shale, peat, oil, natural gases. Solid fuels to artificial include coke, coal briquettes, charcoal. From liquid - fuel oil, gasoline, kerosene, solar oil, diesel fuel. From gas - Gaza domain, generator, coke. Peat, brown coals, stone coals and anthracites were formed in the process of consistent carbonization of mesting vegetable mass.

Further classification of each group can be carried out by their aggregative state on solid, liquid and gaseous fuels.

The composition and quality of fuel is established using chemical and technical analysis. For this, the so-called average sample of this fuel batch is taken, which should most correctly display the properties and composition of the entire batch or reservoir from which fuel is mined. The selection of the middle party is carried out in accordance with the specially designed instructions.

The fuel mined from the subsoil, from the surface of the Earth and delivered to the consumer is called the working fuel. The working fuel includes: carbon (C), hydrogen (H), bat (S L) sulfur, which, during combustion, distinguishes a certain amount of heat, oxygen (O) and nitrogen (N), which are internal ballast of fuel, and finally , ash (a) and moisture (W), constituting the external ballast of fuel. All elements listed above that are part of the fuel are given as a percentage by weight. Fuel in the form in which it goes to the consumer is called a worker, and the substance constituting it is the working mass. The elementary chemical composition is expressed as follows:

C P + H P + O P + N P + S P + A P + W P \u003d 100%

Mineral impurities and humidity of the same grade of fuel in different parts of its deposits and various places can be different, and can also be changed during transportation and storage. More constant is the composition of the combustible mass of fuel. Bearing in mind this circumstance, for a comparative heat engineering assessment of various fuel varieties, the conditional concepts of dry, combustible and organic mass were introduced, which, expressed as percentages, are denoted by the same symbols as the working mass, but, respectively, with the indices "C", " "And" O "instead of the working mass index," P ".

Moisture. The moisture content in solid fuels fluctuates in large limits - from 5% to 60%. The productivity of liquid and gaseous fuels is small. Fuel moisture is divided into external (mechanical) W VN,%, and internal (hygroscopic) w gr,%. They are working humidity.

W p \u003d W VN + W GR, [%]

External moisture is removed from the fuel at its natural drying under room temperature. The decrease in the fuel weight will be ceased when the balance between the pressure of water vapor in fuel and the partial pressure of water vapor in the surrounding air will occur.

Internal moisture is held in the pores of fuel due to the presence of capillary forces and is removed from it only by heating the fuel. In the drying cabinet to 105 0 C. The content of internal moisture in solid fuel comes to 10%. However, the total humidity found in this way turns less truly in the moisture fuel, because in a number of solid fuels contains a crystallization or hydrate moisture associated with some mineral components of fuel: clay, silicates, organic substances. This moisture can be removed from fuel only at a temperature of 800 0 C.

The presence of moisture in the fuel negatively affects its quality, and, consequently, on the operation of the boiler installation, since the amount of combustible substances decreases in the fuel, and, of course, the amount of heat released during its combustion decreases. In addition, part of the heat goes to the evaporation of moisture, and then goes along with pairs from the boiler installation, lowering it k.p.d. It should also be noted the difficulty of inflammation of the fuel containing moisture, the width of the volume of flue gases, which in turn increases the flow rate of electricity with smokers. At low temperatures of the outgoing gases, the presence of water vapor in them causes the risk of condensation of the latter and the occurrence of corrosion of metal surfaces of heating and chimneys.

Ash.A solid non-flammable residue, obtained after the completion of transformations in the mineral part of the fuel in the process of its combustion, is called ash. The yield of the gasifying part of impurities reduces the mass of ash with respect to the initial mineral impurities of fuel, and some reactions, for example, the oxidation of the iron polegan, lead to its increase. Usually, the mass of ash is slightly less than the mass of mineral impurities in the fuel, only in combustible slates due to the decomposition of ash carbonates contained in them

it turns out significantly less compared with the mass of mineral impurities.

Ash as such in the original fuel it does not occur as a result of fuel combustion as a dry residue. In solid fuels, the ash content ranges from 2% to 60%. In liquid and gaseous fuels, the content of the ash residue is extremely small.

The ash is a mixture of various minerals in the fuel. The ash is divided into three types. Primary The ash is in the original material - theneck - in the form of dissolved salts along with soil water and is evenly distributed in it. Secondary The ash enters fuel is also from outside with underground waters or as a result of the burning processes that took place in retros. Both species of this ash are not separated from the fuel. Tertiary The ash is a random impurity in the form of rock captured during the extraction of fuel and separated from it as a result of enrichment.

In the heat chamber at high temperatures, part of the ash melts,

forming a solution of minerals, which is called slag. Slags are removed from the furnaces in a liquid or granular state. To evaluate the degree of cloghood of combustible mass of fuel, ash content belong to its dry mass, expressing it in percent. The ash content is determined by the combustion of the pre-dried fuel sample of a certain mass in a platinum crucible and calcining to a constant mass (solid fuels at a temperature of 800 ± 25 ° C, and liquid fuels - 500 ° C). The ashiness of fuel changes from the percentage of the percentage in fuel oil and wood up to 40-60% in shale.

The ash formed during the combustion of fuel at high temperatures and brief residence time in the furnace chamber, according to its chemical and mineralogical composition differs from the ash, which is formed when analyzing the solidity of fuel combustion in the laboratory.

Important properties of ash are its abrasiveness and smoothness characteristics. High abrasive ash causes strong wear of the convective surfaces of heat generators heating.

Flooring ash is determined by heating in a special furnace in a semi-assessment gas medium of a triangular pyramid of standard sizes with a height of 13 mm and the face of its base is 6 mm made from crushed sample of the ash test (GOST 2057-49).

The following characteristics of the fuse of ash are distinguished:

t 1 - the temperature of the start of deformation, in which the pyramid is bent or the vertex is spinning;

t 2 - the temperature of the softening began at which the top of the pyramid

leans to its base or the pyramid turns into a ball;

t 3 - the temperature of the beginning of the liquid state at which the pyramid

spreads on the stand;

t 0 - the temperature of the start of a truly liquid state at which the melt

the slag is subject to Newton's laws on the flow of true fluid.

According to the characteristics of the flexibility of ash, energy corners are divided into three groups: with a loss-saline T 3<1350 °С, с золой средней плавкости

1350< t 3 <1450 °С и с тугоплавкой золой t 3 >1450 ° C.

The presence of ash in fuel significantly reduces its value and causes difficulties in the process of combustion. The flying ash, carrying into the gas ducts of the boiler, protects and pollutes the heating surfaces, worsening the heat transfer coefficient. Aslant and slag in the boiler groups require special events to remove them.

Carbon. Carbon represents one of the most essential components of each fuel and includes its composition not free state, and the form of complex organic compounds with hydrogen, oxygen, gray and nitrogen. When combustion, pure carbon highlights 8130 kkal \\ kg (34.4 mJ / kg) and is the main source of the calorific value of the fuel. Carbon content in some solid fuels reaches 95%.

Hydrogen. Another important component of the fuel is hydrogen, the content of which in the combustible mass of solid and liquid fuels ranges from 2 to 10%. Many hydrogen is contained in natural gas, fuel oil and combustible slates, least in anthracite. In the calorific value, hydrogen almost 4 times the carbon and its heat of combustion in water vapor is 10.8 mj / m 3 (2579 kcal / m 3) .E

Sulfur. The content of sulfur in solid fuels with the exception of shale is small. When combustion, sulfur highlights a slight amount of heat. Sulfur in the fuel is contained in three species. Organic sulfur S 0 and peregned sq make up the so-called fuel bat sulfur:

S L \u003d S 0 + SK [%]

The third type of sulfur is sulfate sulfate - S A, which is already oxidized and therefore cannot be separated by heat, as a result of which is part of the fuel ash in the form of mineral compounds with iron and calcium. The total content of sulfur in fuel is

SAB \u003d SL + SA [%]

The organic sulfur is part of complex high molecular weight organic fuel compounds. The peregned sulfur is its compounds with metals, more often with iron (FES_2 - Iron Peregnedan), and enters the mineral part of the fuel. Organic and crocedered sulfur s s l _print fuel burning is oxidized with heat release. Sulfate sulfur enters the mineral part of the fuel as CAS0 4 and FES0 4 sulfates and therefore does not expose further oxidation in the process of combustion. Sulfate sulfur compounds are moving into the ash. In a combustible mass of fuel, S O and S K are included, which, when combustion of fuel, go into gaseous compounds SO 2, and in small quantities in SO 3.

The sulfur content in solid fuels is usually small. In oil, sulfur is part of inorganic compounds, in natural gases it is practically absent, in associated gases of some oil fields contain some sulfur in the form of hydrogen sulfide H 2 S and sulphous gas SO 2. Sulfuric gas formed during combustion of fuel and the sulfuric gas SO 3 in a small amount in small quantities cause corrosion of metal parts of heat generators and poison the surrounding area. Due to the low heat of combustion - 9.3 MJ / kg (2220 kkal / kg), the presence of sulfur reduces the heat of combustion of fuel. Therefore, sulfur is a harmful and unwanted admixture of fuel.

Nitrogen and oxygen belong to the inner ballast of fuel. Nitrogen is an inert gas. Its content in solid fuel is 1-2% and when combustion of fuel, it is highlighted in a free state.

The content of oxygen in the fuel fluctuates widely, reaching 40%. It is believed that all oxygen in the fuel is associated with hydrogen and when combustion of fuel form water vapors. In addition, oxygen, being in a compound with hydrogen or carbon fuel, translates some part of the combustible to the oxidized state and reduces its heat of combustion. The oxygen content is large in wood and peat. Nitrogen when burning fuel in the air atmosphere is not oxidized and passes into combustion products in free form.

Fuel is combustible substances, the main part of which is carbon used in order to obtain thermal energy when burning them.

Classification. By physical state, fuel is solid, liquid, gaseous. Glass furnaces operate on liquid and gaseous fuel.

A number of requirements are made to the fuel used for glass furnaces: during combustion, it should highlight a significant amount of heat per unit of its mass or volume, should not be separated by gases harmful to people acting on the health, as well as adversely affecting the materials of the furnaces and furnaces, must be Convenient for transportation and combustion.

The main characteristic of the fuel is its calfness Q. The caloriness of the fuel is called the amount of heat allocated in full combustion of the mass unit or the volume of fuel (1 kg of liquid fuel or 1 m 3 of gaseous). Callerity is measured in kcal / kg or kcal / m 3 (in CJ CJ / kg, KJ / m 3).

The caloriness of various fuels fluctuates widely - from 1000 to 10,000 kcal / kg.

By origin, fuel is divided into natural and artificial. The latter is obtained as a result of the processing of natural fuel. In tab. 3 Classification of industrial fuel is given.

In industry, solid, liquid and gaseous fuel are used. The natural fuel is distinguished on the surface of the Earth or in its depths, and artificial, obtained by processing natural.

The main requirements for technological fuels include: low production costs, low cost of transportation, ease of use, the ability to use with a high efficiency, a small content of harmful impurities.

Various types of fuel (solid, liquid and gaseous) are characterized by common and specific properties. The common properties of fuel include heat of combustion and humidity, to specific - ash content, sulfur (sulfur content), density, viscosity and other properties.

Heat combustion - The amount of heat that stands out with full combustion of 1 kg or 1 m 3 of fuel. The energy value of the fuel is primarily determined by its warmth of combustion.

The highest and low heat of combustion is distinguished. The lowest heat of combustion differs from the highest amount of heat spent on the evaporation of moisture contained in the fuel and formed during the combustion of hydrogen. The lower heat of the combustion is taken into account for calculating the need for fuel and its cost in the preparation of heat balances and determining the efficiency of the installations that use fuel. In comparison of various types of fuel, we use the concept of conditional fuel characterized by lower heat of combustion, equal to 29 MJ / kg.

Humidity (moisture content) of fuel reduces its heat of combustion due to increased heat consumption for evaporation of moisture and increasing the volume of combustion products (due to the presence of water vapor).

Solitude - The amount of ash formed during the combustion of the mineral substances contained in the fuel. Mineral substances contained in fuel lower its heat of combustion due to a decrease in the content of combustible components (the main reason) and increase the heat consumption for heating and melting mineral mass.

Sulfur (sulfur content) refers to a negative fuel factor, since sulfuric gases contaminating the atmosphere and destroying metal are formed during its combustion. In addition, the sulfur contained in the fuel is partially moving into a metal welded metal, reducing their quality. For example, for cooking crystal, optical and other glasses, it is impossible to use a fuel containing sulfur, since sulfur significantly reduces the optical properties and a glass of glass.

Composition of fuel. Fuel of various species, deposits and mines differ in its composition. When considering solid and liquid fuel, it is customary to distinguish between its components: carbon, hydrogen, sulfur, oxygen, nitrogen, ash and moisture. In relation to the gaseous fuels, under the composition, they are mainly understood: carbon oxide, hydrogen, methane, ethane, propane, butane, ethylene, benzene, hydrogen sulfide, etc. Particular oxygen and nitrogen are among the fuel to external.

The composition of solid and liquid fuels is expressed as a percentage by weight, gaseous - as a percentage of volume.

Solid and liquid fuel consists of combustible and non-combustible parts. The combustible part of the fuel includes carbon, hydrogen, oxygen, nitrogen and sulfur. Oxygen and nitrogen are not lit; They are included in the composition of the combustible mass conditionally. Therefore, a fuel part of the fuel is called conditionally combustible mass. The non-combustible part of the fuel is ballast - consists of moisture and ash. The organic mass of fuel is carbon, oxygen and nitrogen.

Fuel in the form in which it enters the furnace furnace to burn, is the name of the working fuel. Due to the fact that the content in it moisture can fluctuate in wide limits, the composition of the fuel is often characterized by its dry mass.

To designate the composition, to which the content of a particular element in fuel includes, apply the indices O, G, C and P, which are readable, respectively: O - organic mass; g - combustible mass; C - dry fuel; P - working fuel. For example, CO is the carbon content in the organic mass; SR - sulfur content in conditionally combustible mass; AC - content, ash in dry fuel; WP - moisture content in working fuel.

Under energy fuel, combustible substances are understood, which are economically appropriate to use for heat and electrical energy. According to the aggregate state of fuel, they are divided into solid, liquid and gaseous. By origin - on natural, formed from the remains of plant and animal origin for a long time, and artificial, obtained as a result of processing natural fuels. The first includes coal, oil, natural gas. To the second - coke, briquettes, carbon waste, diesel fuel, fuel oil, domain, coke and generator gases.

The fuel consists of a combustible and mineral part and moisture. The composition of the combustible part includes carbon C, hydrogen H and sulfur s, which are in complex compounds with oxygen o and nitrogen N. An important characteristic of the fuel is the heat of combustion. The heat of combustion is the amount of heat released in full combustion of fuel. There are lower and high heat of combustion.

Carbon is the main part of the fuel. The greater it in the composition, the higher the heat of the combustion of the fuel. The carbon content by mass in solid fuels ranges from 25 (slate and peat) to 70% (anthracite). Hydrogen is contained in fuel in a small amount of 2-10%. The heat of its combustion is 4 times more than carbon. Oxygen is part of the fuel in the form of various compounds, including with combustible elements, which reduces the amount of heat separated by fuel combustion. Therefore, oxygen is believed to the ballast of fuel. Nitrogen also refer to the fuel ballast. It is small content (in solid fuel up to 3% by weight). When combustion, most of the fuel nitrogen goes into toxic oxides N0 and N0 *.

Sulfur depending on the type of compound into which it enters is divided into organic S0, if it is associated with carbon, hydrogen, nitrogen and oxygen; Pedaginal SK - connection with iron (usually it is an iron colentan); Sulfate SC, which is in the form of compounds FES04, MGS04, CAS04. Sulfur, which is part of organic and criedd compounds, participates in the process of burning, highlighting the warmth and forming a sulfur

S02 and sulfur S03 anhydrides. Therefore, often organic and criedst sulfur is called a volatile combustion

The sulfur, which is part of FES04, MgS04, CAS04, etc., does not burn, so, when burning fuel, sulfates are practically not decomposed. In solid fuel, the sulfur content reaches 5%, in liquid 3.5%. The presence of sulfur in fuel is undesirable, since the sulfur sulfur sulfur oxides S02 and S03 in the presence of moisture give solutions of sulfur and sulfuric acid, which cause corrosion of pipes for the heating surfaces of the convective boiler shaft and have a harmful effect on the environment.

Under the mineral part of the fuel, the non-combustible impurities. Their amount depends on the origin of fuel and its production technology. There are internal mineral impurities formed during the formation of coal deposits, and external mineral impurities that have fallen into fuel during its prey from the adjacent breeds. Internal mineral impurities, in contrast to external, quite evenly distributed in the fuel and therefore practically cannot be separated from the combustible mass.

When burning fuel from mineral impurities, Azola A. It characterizes the mineral part of the fuel. The ash content in the fuel is determined by the magnitude of the solid residue obtained after burning the pre-dried fuel sample of a certain mass in platinum crucible and the subsequent calcination to a constant mass value at a temperature of 800 ° C. When designing boilers, and primarily their furnaces, the temperature characteristic of the federation of ash is important. It depends on the composition of the ash and the surrounding gas environment. Flood estimate is carried out at the temperatures of three ash conditions: U - the beginning of the deformation; T2 - began softening; T3 - liquid state:

To take measures to exclude contamination of the surfaces of heating, located behind the furnace, it is important to know the temperature of solidification of ash. Usually this temperature is 50 ° C below T2. When burning fuel in the furnace in the high temperature zone, there is a partial or complete melting of ash. Some part of it is carried away with combustion products from the furnace. The remaining ash, partially decomposing, is melted or sinters into the slag, which is then removed from the bottom of the furnace in a liquid or solid state. Under the action of high temperatures, the oxide contained in the slag together with other substances form multicomponent compounds, and the melting point of slag differs from the temperature TS of the liquid ash. In the furnaces with liquid slag adlation for the free leakage of the slag from the furnace, its temperature should be higher than the temperature of the TS of the liquid - fusible state of ash. This temperature is called temperature / nzh normal liquid slag adlation, it is determined by 22

Chemical composition of slag. As a rule, \u003d Ta + (100-4- 200) ° C.

Moisture w, like the mineral part, is a ballast of fuel. It reduces its warmth of combustion. In addition, part of the heat of burnt fuel is consumed on its evaporation. The moisture contained in the fuel is divided into external and internal (hygroscopic). External moisture enters the fuel when it is mining, transporting and stored. The amount of it varies widely with 1-40%. External moisture can be removed from the fuel when it is drying. The inner moisture is connected both with the organic part of the fuel and mineral. It includes colloid and hydrate moisture. Colloid moisture forms gels with fuel. Its quantity depends on the nature and composition of fuel, content / moisture in atmospheric air. Hyded moisture is chemically associated with mineral fuel impurities. It is small content. When drying fuel, part of the colloid moisture evaporates, and the content of hydrate moisture does not change.

Wet solid fuels in air lose moisture, and the dried acquires it. These processes occur before the equilibrium occurs between the partial pressure of water vapor in the air and fuel. The fuel with the moisture obtained in this way is air-dry. If the air-dry fuel is heated at atmospheric pressure to a temperature of 105 ° C, then all the moisture from the fuel will be practically removed. The amount of moisture removed from air-dry fuel is called the HRH hygroscopic humidity.

The composition of the fuel in the form in which it enters the TPP, a set of separate elements and a component (by weight for solid and liquid fuel), is called a working weight of the fuel:

Toc O "1-3" H z Cp + No. + SP 4-OP + NP + WP + AP \u003d 100%. (one)

If an external and internal moisture is removed from the fuel, then dry mass has the following composition:

CC-J-HC-FSC + OC-FNC + AC \u003d 100 O / 0. (2)

Excluding as a dry mass of ash, we get a fuel mass of fuel

CR + HR + SR + OR-F № \u003d 100%. (3)

If the cried sulfur is separated from the flammable mass, then the remaining mass of the fuel is called the organic mass

SG + NG + og + № \u003d 100%. (four)

The composition of the working and dry masses of the same fuel, depending on the conditions of production and weather, can fluctuate in fairly wide limits. The composition of the combustible mass of fuel is constant. Therefore, it is used to carry out the recalculation of dry and working masses. Cutting formulas, for example, with a working

2. The coefficient of recalculation of the composition of solid and liquid heat from one mass to another

A set mass	Sky mass
		Organic






Organic

Mass on dry is easy to obtain, since 1 kg of working mass contains (100- 2) / 100 (kg) of dry mass of fuel. Therefore

CP + HP + SP + O "+ NP + W" H - A "_ 100 ~

C + NA -) - SC + OS + NE + AC 100 - W "100 100"

Cf \u003d s (100- WP) / 100: HP \u003d NA (100-WP) / 100

Recalculation coefficient (100 -WP) / 100 is constant for all fuel elements. The coefficients of recalculation of the composition of solid and liquid fuels from one mass to another are shown in Table. 2.

If the fuel is heated without air access, then from it as a result of the thermal separation of unstable oxygen-containing hydrocarbon compounds, volatile substances are distinguished and the solid non-volatile residue remains. The exit of the volatile and the properties of the solid residue are important heat-engineering characteristics of solid fuel.

The exit of volatile ul is determined by a decrease in the fuel combustible mass during it heating 7 minutes without access at 850 ° C and expressed in% fuel combustible mass. The volatile usually includes hydrogen, hydrocarbons, oxide and carbon dioxide. The value of the volatile and the temperature of the 4th beginnings of their exit depend on the age of fuel. The higher the output of volatile and below the temperature of the beginning of their allocation, the easier the fuel is ignited. The greatest exit of volatile and na - 24

Smaller temperatures of the beginning of their output have young fuels: the peat Vr "\u003d 70%, * out \u003d 100-g - at ° C; at brown coal. thu \u003d "40-1-65%; W 130-І-170 ° C.

The solid residue, which remains after the exit of volatile fuels can be the idea, weaken and powdered. Only some stone coals give a dense sandpaper 1 residue with a large number of pores, called coke.

The warmth of the combustion of fuel is determined by the experimental way. The amount of heat released depends on the final state of combustion products and, in particular, in which aggregate state is moisture (in the form of steam or water). In this regard, the highest qb and low heat of combustion are distinguished.

The difference between QJJ and Ql is that the first takes into account the heat, which is allocated during the condensation of water vapor (moisture in combustion products is in the form of water), and the second this warmth does not take into account. Since in the boiler, the temperature of combustion products is sufficiently high and the condensation of water vapor does not occur, the heat spent on the evaporation of moisture is lost. Therefore, in thermal calculations, the lowest heat combustion of the working fuel is used. If QB is known, then \u003d ql - 25.2 (WP / 100 + 9N7U0),

Where 25.2 (WP / 100 + 9№ / 100) is the amount of heat spent on the evaporation of moisture (WP / Yo) contained in the fuel, and water (9NR / 100), which is formed during the burning of hydrogen, KJ / kg;

25.2 MJ / kg - the value of the hidden heat of vapor formation for water at a pressure of 0.1 MPa.

In the absence of experimental data, approximate value for solid fuel and fuel oil can be found according to the formula proposed by D.N. Mendeleev,

Qs \u003d 0.339cp + 1.03np - 0.109 (OR - SP) - 0,259wp.

To compare various fuels, the concept of conditional fuel is used, i.e. the fuel, the heat of the combustion of which is equal

29.3 MJ / kg. The concept of conditional fuel is used in determining various fuel resources, comparing specific fuel consumption per unit of energy generated and carrying out technical and economic calculations. With a comparative evaluation of the quality of fuels are convenient to the lower heat combustion, the characteristics of the fuel% kg / MJ:

WN \u003d WP / QP "; Ap \u003d AP / QP; Sn \u003d SP / QH-

The above characteristics of the fuel WN, A and S are shown how much of 1 mJ lower heat of combustion accounts for moisture, ash and sulfur, in% of the working mass of the fuel. Depending on the above humidity, it is customary to be fuels: low-voltage with w "\u003d 0.7% - kg / mJ, medium humidity with WN \u003d 0.7C - 1.89% CG / MJ, high-voltage with WN\u003e 1.89% ■ kg / MJ.

Solid fuels is characterized by abrasiveness - a property of contact with other materials cause wear of the latter, which depends on the amount of sulfur, ash and composition contained in it. This fuel characteristic is important for the choice of equipment of the dust preparation system.

The hardness of solid fuel and the resistance to its grinding (grinding) is characterized by the coefficient of grinding nobility & los (the ratio of the specific consumption of electricity spent on the grinding of anthracite, to the specific energy consumption required for the fuel under consipation). The softer fuel, the greater the KNO value. This fuel indicator is taken into account when designing dust preparation systems and, first of all, when choosing a type and productivity of grinding equipment.

The density of solid fuel (in kg / m3), as one of its characteristics, is widely used in the calculations of the loading, storage and fuel systems to the dust preparation systems. Distinguish seeming and bulk density. Under the apparent density, we understand the mass of the unit of a piece of fuel with internal pores filled with air and moisture. The bulk density is a mass of fuel contained in a unit of volume filled with slices of fuel, i.e., also takes into account the volume of air between pieces of fuel.

Fossil solid fuels are divided into peat, brown, stone coals and anthracite. Peat - geologically the most young solid fuel. It is characterized by a low degree of decomposition of organic residues and a relatively low heat of combustion, an increased content of volatile (in "l and 70%), hydrogen (NG \u003d \u003d 5h-6%), oxygen (ада\u003e 30%) and nitrogen (NR \u003d 2- ^ 2.5%). Torf is characteristic of very high hygroscopicity and humidity (WP \u003d 35 - \u003d - 60%).

To brown coals (brand b) include coals with the highest warmth of the combustion of the solutions of the solutions Q | L00 / (L00 - AR)< < 23,9 МДж/кг. По геологическому происхождению они близки к торфу. В бурых углях достаточно велико содержание летучих (К = 65-М0 %), водорода (Нг = 4-f-6,5 % и более) и кислорода (Ог = 15ч-30 %). Они отличаются высокой гигроскопичностью и влажностью, содержание углерода достаточно велико (Сг = = 55-^78 %), а количество слаборазложившихся растительных остатков мало. По влажности бурые угли классифицируют: Б1 - с влажностью более 40 %; Б2 - с влажностью 30-40 % и БЗ - с влажностью менее 30 %.

; Stone belongs to coals, in which 100 / (100 - AR) \u003e\u003e 23.9 MJ / kg. They are characterized by high carbon content (75-97%), density and heat of combustion. With an increase in carbon content, the fraction of oxygen, hydrogen and volatile in the fuel is reduced. Upon exiting volatile taking into account the ability 26

Singing a solid residue adopted the following classification of stone coal: long-flames (D), gas (g), gas fat - housing (GJ), fat (g), coke-bold (kzh), coke (K), enriched hitting (OS) Web (SS), skinny (T). As they transition from the coal of the brand, the exit of volatile varies from 36% or more (D) to 9-17% (T), and humidity, respectively, from 14 to 5%.

To semiracitis (PA) and anthracites (a) include coals with QE 100 / (100 - AR)\u003e 23.9 MJ / kg and the output of volatile less than 9% contains 89-F-92.5% of SG, 2-P , 6% HR, 0.8-FL, 3% NR, 2.2-5% OR, 0.64-0.9% SR.

At semiracitis, the exit of volatile more than 5% and the heat of combustion is higher than that of anthracite. PA and A are highly durable fuels; In the energy boilers use their waste.

According to the size of the mining of pieces, coal is classified as follows: Plate (P), large (K), Walnut (o), small (m), seed (s), shtyb (w) and ordinary (P). The size of coal pieces from class K to class w decreases from 50-100 to 6-13 mm. In the class W chips of coal smaller 6 mm, and in the class p, the size of pieces is unlimited and can be 0-200 (300) mm. In tab. 3 shows the characteristic of solid fuel of some deposits.

Liquid fuel is characterized by the conditional viscosity and temperature of frozen and flash. Conditional viscosity is made to express in conditional degrees (Wu). It is determined as the ratio of the arbitrariness of a certain volume (2-yu-4 m3) of liquid fuel to the time of leakage of the same volume of water at a temperature of 20 ° C.

The conditional viscosity of liquid energy fuel (fuel oil) is usually included in its marking. So, the numbers standing after the letter M, in the fuel oil marks (for example, M 40 and M 200) - the conditional viscosity at a temperature of 50 ° C (respectively 40 and 200 ° W). Conditional viscosity strongly depends on temperature:

° vu, \u003d ° vbous (50 / g) p,

Where ° BYJ is the conditional viscosity of liquid fuel at temperatures ° v50 - the conditional viscosity at T \u003d 50 ° C; P is an indicator degree depending on the value of ° V50.

Below are the values \u200b\u200bof the conditional viscosity ° V50 at various

"Woo ............................................ 2 5 10 15 twenty

I. ................................................ . 1.8 2.3 2.6 2.75 "2.86

For high-quality sputtering and reliable transportation of liquid fuel through pipelines, its viscosity should not exceed 2-3 ° W. To perform this condition, a pre-heating of fuel is required. The heating temperature of the fuel oil depends on its brand and is 80-140 ° C.

3. Characteristics of solid fuel

Fuel deposit			Elementary composition (working mass),%

Donetsk

Kuznetskaya
Karaganda
Ekibastuzskoye
Near Moscow

Babaevskoye
Kizelovskoye
Chelyabinsk,
Kansko-Achinskoye
Nazarovskoye
Irsh Borodin

Azey

The temperature of the frozen is the minimum temperature in which the fluid loses fluidity, and the drain and pumping it becomes impossible. Mazut this temperature depends on the brand and is 5-25 ° C.

The temperature of the flash is the temperature in which the pairs of liquid fuel in the mixture with air flashes when contact with the flame. For fuel oil, the flare point is 80-140 ° C. With an open heating system of fuel oil, its temperature should be below the flash temperature by 10-15 ° C.

As an artificial liquid fuel in the boilers, the fuel oil of three marks is used: M40, ML00 and M200 - a heavy residue of oil distillation, resulting from light fractions (gasoline, kerosene, ledroin, etc.). Mazut - Malozol and almost anhydrous fuel. It is classified according to the content of sulfur connections and viscosity. By the number of sulfur-containing compounds, fuel oil are divided into a minor (SC< 0,5 %), сернистый (Sc = 0,5-2 %) и высокосернистый (Sc > 2%). In the "main directions of economic and social development of the USSR for 1986-1990 and for the period up to 2000", it is indicated for the need to significantly reduce the use of fuel oil as fuel, primarily on the TPP.

Gaseous fuel is a mixture of flammable (hydrogen H2, hydrocarbons of the methane row, heavy hydrocarbons of sleep, hydrogen sulfide H2S and carbon oxide CO), a small amount of non-combustible gases (oxygen OA, nitrogen Na, dioxide 28

Temperature	Exit Volatih	Heat combustion	The coefficient is uncommon - ilod - sobc cl0	Air volume and combustion at a	Products \u003d 1 m / kg

Carbon C02 and water vapor H20). The composition is recorded in the form of components of its compounds (in% of volume). All calculations are carried out on the basis of a unit of dry gas, taken under normal conditions (0.1 MPa pressure and temperature 20 ° C)

CH4 + C2NV + C3N8 + ■ ■ + H2 + H2S + CO + N2 + C02 +

The heat of the combustion of gaseous fuels under normal conditions and the known content of gases included in its composition,

Qm \u003d 0.01)

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