Regulation of the combustion process (Basic principles of combustion). Flue gases Mounted chimneys
During the combustion of solid fuel, as is known, a residue is formed - ash in the form of small (powdery) particles and large pieces - slag. During layer combustion of fuel various types the bulk of the ash (approximately 75-90%) remains in the furnace and flue ducts of the boiler, and the rest (fine) is carried away by the flue gases into the atmosphere.
When flaring solid fuel (in the form of dust), ash carryover with flue gases will increase significantly and reach 80-90%. The ash and unburnt tiny particles of fuel removed in this way (entrainment) pollute the atmosphere and, therefore, worsen the sanitary and hygienic conditions of the surrounding area. Fly ash emitted into the atmosphere is very fine, it can easily penetrate the eyes and lungs of a person, causing great harm to health. Therefore, before releasing them into the atmosphere, flue gases must be cleaned of ash and entrainment in special devices - ash collectors (for example, ZU ash collectors), which are equipped in almost all modern boiler houses operating on solid fuel.
Boiler plants in large cities are leaders not only in the amount of harmful emissions into the environment, but also in their toxic effects. Regular assessments of the environmental impact of highly toxic substances show that air quality in large Russian cities is deteriorating every year. As a result, the number of people with respiratory diseases among the population of these cities is increasing; Residents of megacities have decreased immunity and increased incidence of cancer.
Studies of flue gases from fuel combustion plants show that the main atmospheric pollutants in their composition are carbon oxides (up to 50%), sulfur oxides (up to 20 percent), nitrogen oxides (up to 6-8%), hydrocarbons (up to 5-20%). ), soot, oxides and derivatives of mineral inclusions and hydrocarbon fuel impurities. In turn, exhaust and exhaust gases of thermal engines emit into the air more than 70 percent of carbon oxides and hydrocarbons (benzenes, formaldehydes, benzo(a)pyrene), about 55 percent of nitrogen oxides, up to 5.5 percent of water, as well as soot ( heavy metals), burning, soot, etc.
Flue gases from boiler plants and engines contain tens of thousands of chemicals, compounds and elements, more than two hundred of which are highly toxic and poisonous.
When released into the atmosphere, emissions contain reaction products in solid, liquid and gas phases. Changes in the composition of emissions after their release can manifest themselves in the form of: precipitation of heavy fractions; disintegration into components by mass and size; chemical reactions with air components; interaction with air currents, clouds, precipitation, solar radiation of various frequencies (photochemical reactions), etc.
As a result, the composition of emissions may change significantly, new components may be formed, the behavior and properties of which (in particular, toxicity, activity, ability to perform new reactions) may differ significantly from the original ones. Not all of these processes are currently studied with sufficient completeness, but the most important ones are available. general ideas relating to gaseous, liquid and solid substances.
The greatest environmental damage to the atmosphere and environment natural environment in general, they cause substances such as nitrogen and carbon oxides, aldehydes, formaldehydes, benzo(a)pyrene and other aromatic compounds, which are classified as toxic substances.
In addition, during the operation of any installation and engine, about 1.0-2.0 percent of the fuel consumed is emitted, which settles on surfaces (ground, water, trees, etc.) in the form of unburned hydrocarbons, soot, dust and ash.
Flue gases have an unpleasant odor and have harmful and sometimes fatal effects on the human body, flora and fauna. Gas and thermal air pollution contributes to the formation of acid rain, atmospheric smoke, and changes the nature of cloudiness, which leads to an increase in the greenhouse effect.
The greatest danger to humans and living organisms are the components that cause cancer; these are carcinogenic substances represented in smoke and exhaust gases by polycyclic aromatic hydrocarbons (C X H Y).
Those with greater carcinogenic activity include, first of all, 3,4 benzo(a)pyrene (C 2 0H 12), which is formed when the organization of the combustion process is disrupted. The highest yield of carcinogenic substances, in particular 3,4 benzo(a)pyrene, is observed in non-stationary and transient modes.
Main pollutants
Sulfur dioxide, or sulfur dioxide (sulfur dioxide).
The most widespread sulfur compound is sulfur dioxide (SO 2) - a colorless gas with a pungent odor, approximately twice as heavy as air, formed during the combustion of sulfur-containing fuels (primarily coal and heavy fractions of oil).
Sulfur dioxide is especially harmful to trees, causing chlorosis (yellowing or discoloration of leaves) and dwarfism. In humans, this gas irritates the upper respiratory tract, as it easily dissolves in the mucus of the larynx and trachea. Chronic exposure to sulfur dioxide can cause a respiratory disease similar to bronchitis. This gas itself does not cause significant damage to public health, but in the atmosphere it reacts with water vapor to form a secondary pollutant - sulfuric acid (H 2 SO 4). Drops of acid are transported over considerable distances and, when they enter the lungs, severely destroy them. The most dangerous form of air pollution occurs when sulfur dioxide reacts with suspended particles, accompanied by the formation of sulfuric acid salts, which penetrate into the lungs during breathing and settle there.
Carbon monoxide, or carbon monoxide.
A very poisonous gas without color, smell or taste. It is formed during incomplete combustion of wood, fossil fuels, during the combustion of solid waste and partial anaerobic decomposition of organic matter. IN indoors filled with carbon monoxide, the ability of red blood cell hemoglobin to carry oxygen decreases, which causes a person’s reactions to slow down, perception to weaken, headaches, drowsiness, and nausea to appear. Under the influence of large amounts of carbon monoxide, fainting, coma, and even death can occur.
Suspended particles.
Suspended particles, including dust, soot, pollen and plant spores, etc., vary greatly in size and composition. They can either be directly contained in the air or be contained in droplets suspended in the air (aerosols). In general, about 100 million tons of aerosols of anthropogenic origin enter the Earth’s atmosphere every year. This is about 100 times less than the amount of aerosols of natural origin - volcanic ash, wind-blown dust and sea water spray. Approximately 50% of anthropogenic particles are released into the air due to incomplete combustion of fuel in transport, factories, factories and thermal power plants. According to the World Health Organization, 70% of the population living in cities in developing countries breathes highly polluted air containing a lot of aerosols.
Aerosols are often the most obvious form of air pollution, as they reduce visibility and leave dirty marks on painted surfaces, fabrics, vegetation and other objects. Larger particles are mainly captured by the hairs and mucous membranes of the nose and larynx and then expelled. It is assumed that particles smaller than 10 microns are most dangerous to human health; They are so small that they penetrate the body's protective barriers into the lungs, damaging the tissues of the respiratory organs and contributing to the development of chronic respiratory diseases and cancer. Other types of aerosol pollution complicate bronchitis and asthma and cause allergic reactions. The accumulation of a certain amount of small particles in the body makes breathing difficult due to blockage of capillaries and constant irritation of the respiratory system.
Volatile organic compounds (VOCs). These are toxic fumes in the atmosphere. They are the source of many problems, including mutations, respiratory disorders and cancer, and also play a major role in the formation of photochemical oxidants.
Anthropogenic sources release many toxic synthetic organic substances into the atmosphere, such as benzene, chloroform, formaldehyde, phenols, toluene, trichloroethane and vinyl chloride. The main part of these compounds enters the air during incomplete combustion of hydrocarbons from automobile fuel, at thermal power plants, chemical and oil refineries.
Nitrogen oxides NO x Nitrogen oxide (NO) and dioxide (NO 2) are formed during the combustion of fuel at very high temperatures (above 650 o C) and excess oxygen. Subsequently, in the atmosphere, nitrogen oxide is oxidized to gaseous dioxide of a red-brown color, which is clearly visible in the atmosphere of most large cities. The main sources of nitrogen dioxide in cities are car exhaust gases and emissions from thermal power plants (which use not only fossil fuels). In addition, nitrogen dioxide is formed during the combustion of solid waste, as this process occurs at high combustion temperatures. NO 2 also plays an important role in the formation of photochemical smog in the surface layer of the atmosphere. In significant concentrations, nitrogen dioxide has a pungent, sweetish odor. Unlike sulfur dioxide, it irritates the lower respiratory system, especially the lung tissue, thereby worsening the condition of people suffering from asthma, chronic bronchitis and emphysema. Nitrogen dioxide increases susceptibility to acute respiratory diseases such as pneumonia.
When nitrogen oxides dissolve in water, acids are formed, which are one of the main causes of so-called “acid” rain, leading to the death of forests. The formation of ozone in the ground layer is also one of the consequences of the presence of nitrogen oxides in it. In the stratosphere, nitrous oxide initiates a chain of reactions that leads to the destruction of the ozone layer, which protects us from the effects of ultraviolet radiation from the Sun.
Ozone O 3. Ozone is formed by the breakdown of either an oxygen molecule (O2) or nitrogen dioxide (NO2) to form atomic oxygen (O), which then combines with another oxygen molecule. This process involves hydrocarbons that bind the nitric oxide molecule to other substances. Although ozone plays an important role in the stratosphere as a protective shield that absorbs short-wave ultraviolet radiation, in the troposphere it destroys plants as a strong oxidant. Construction Materials, rubber and plastic. Ozone has a characteristic odor that is a sign of photochemical smog. Inhalation by humans causes coughing, chest pain, rapid breathing, and irritation of the eyes, nasal cavity, and larynx. Exposure to ozone also leads to a deterioration in the condition of patients with chronic asthma, bronchitis, emphysema and those suffering from cardiovascular diseases.
Carbon dioxide CO 2 Non-toxic gas. But the increase in the concentration of technogenic carbon dioxide in the atmosphere is one of the main reasons for the observed climate warming, which is associated with the greenhouse effect of this gas.
Positive traits:
· higher heat transfer to heat exchange surfaces than air (due to the greater emissivity of combustion product particles).
Negative qualities:
Consequences:
· the use of flue gases as a coolant is possible only when using intermediate heat exchange devices to heat the coolant supplied directly to the consumer;
· utilization (saving and use) of the heat of exhaust flue gases is ensured;
· in the presence of substances with high corrosive activity (for example, sulfur compounds), the durability of heat pipes and heat exchange devices is sharply reduced;
· when flue gases are cooled below the dew point, condensation may form and, as a result, dampening of structures and the formation of ice in winter.
Classification of heating stoves:
By heat capacity:
· Non-heat-intensive
I have low thermal inertia. The room is heated only during combustion of fuel. Designed for short-term heating. These ovens include:
1) metal (steel or cast iron)
2) stoves made of a small number of bricks (up to 300 pcs.),
3) fireplaces (brick niches for open burning of fuel).
· Heat-intensive
They have great thermal inertia. The stove material accumulates heat and, after combustion of the fuel, transfers it to the room for a long time (up to 12 hours). Used for continuous heating of rooms.
Heat-intensive furnaces differ in design according to flue gas flow diagram
· Duct . The movement of gases is carried out through internal channels, which can be connected in parallel or in series.
· Channelless (bell-type). The movement of gases is free, and at the end of the fire the furnace does not cool down, since hot flue gases accumulate above the entrance to the chimney. The upper zone is somewhat overheated.
· Combined . Before entering the hood, flue gases pass through channels located below the firebox, which allows the lower zone to be heated and a more uniform temperature distribution in the room to be achieved.
Gas and smoke emissions enter the water bodies in the process of mechanical settling or with precipitation. They contain solid particles, sulfur and nitrogen oxides, heavy metals, hydrocarbons, aldehydes, etc. Sulfur oxides, nitrogen oxides, hydrogen sulfide, hydrogen chloride, interacting with atmospheric moisture, form acids and fall out in the form of acid rain, acidifying water bodies.[... ]
FLUE GASES - gases formed during the combustion of fuels of mineral or vegetable origin.[...]
A significant danger is posed by gas and smoke compounds (aerosols, dust, etc.) settling from the atmosphere onto the surface of drainage basins and directly onto water surfaces. The density of deposition, for example, of ammonia nitrogen on the European territory of Russia is estimated on average at 0.3 t/km2, and for sulfur - from 0.25 to 2.0 t/km2.[...]
If coal is treated with chemically active oxygen-containing gases (water vapor, carbon dioxide, flue gases or air) at high temperature, then the resinous substances will oxidize and collapse, closed pores will open, which will lead to an increase in the sorption capacity of coal. However, strong oxidation promotes burnout of micropores, thereby reducing the specific surface area and sorption properties of coal. In practice, the yield of active carbon is 30-40% of the weight of dry raw coal.[...]
Gas and smoke emissions pose enormous harm to the normal functioning of soils. industrial enterprises. The soil has the ability to accumulate pollutants that are very dangerous to human health, for example heavy metabolites (Table 15.1). Near a mercury plant, the mercury content in the soil due to gas and smoke emissions can increase and be hundreds of times higher than permissible. [...]
Existing methods reducing the concentration of nitrogen oxides in the exhaust gases of industrial enterprises are divided into primary and secondary. The primary methods for reducing the formation of nitrogen oxides are the improvement of technologies that emit pollutants into the environment. In the energy sector, for example, this is flue gas recirculation, improving burner designs, and regulating blast temperature. Secondary methods include methods for removing nitrogen oxides from waste gases (smoke, exhaust, ventilation).[...]
Phenol-containing wastewater is cooled to an optimal treatment temperature of 20-25 °C, purged with carbon dioxide (flue gases) to convert phenolates into free phenols, and then fed for extraction. The degree of phenol extraction reaches 92-97%. The residual content of phenols in treated wastewater is up to 800 mg/l. In most cases, this is sufficient for further use of wastewater.[...]
The combustion of oil sludge, especially those obtained from the processing of sulfurous oils, must be carried out so that the gases formed during combustion do not pollute the atmospheric air. This problem is given serious attention, and many sludge processing plants are equipped with special afterburning devices and devices for collecting dust and acid gases. Known, for example, is a thermal afterburner with a capacity of 32 million kcal/h, operating in a complex of installations for burning oil sludge. The afterburner has two combustion chambers, the second of which is designed to increase the efficiency of sludge combustion and reduce atmospheric pollution by products of incomplete combustion. The temperature in the second chamber reaches 1400 C. Additional heat is supplied using burners running on natural gas. Flue gases are cleaned in a scrubber, irrigated with water in an amount of 3600 l/h. Purified gases are released into the atmosphere through a chimney 30 m high.[...]
Main soil pollutants: 1) pesticides (toxic chemicals); 2) mineral fertilizers; 3) waste and industrial waste; 4) gas and smoke emissions of pollutants into the atmosphere; 5) oil and petroleum products.[...]
Currently, scientific research continues to develop more radical and cost-effective methods for purifying “sulfur dioxide from smoke and ventilation emissions.[...]
The distribution of technogenic impurities depends on the power and location of the sources, the height of the pipes, the composition and temperature of the exhaust gases and, of course, on meteorological conditions. Calm, fog, and temperature inversion sharply slow down the dispersion of emissions and can cause excessive local air pollution and the formation of a gas-smoke “cap” over the city. This is how the catastrophic London smog arose at the end of 1951, when 3.5 thousand people died in two weeks from a sharp exacerbation of pulmonary and heart diseases and direct poisoning. Smog in the Ruhr region at the end of 1962 killed 156 people in three days. There are known cases of very serious smog phenomena in Mexico City, Los Angeles and many other large cities.[...]
To neutralize sulfur-alkaline wastewater by carbonization, an installation was built at the plant. During the startup process, it was found that the raw material for producing carbon dioxide (flue gases from one of the technological flameless combustion furnaces) could not be used due to the presence of oxygen, which quickly oxidizes mono-ethanolamine. Oxygen entered the flue gases through leaks in the furnace lining, which became under vacuum when the smoke exhausters were turned on, supplying flue gas to the absorber.[...]
Let's look at how protection is currently carried out environment from solid household and industrial, as well as from radioactive and dioxin-containing waste. Let us recall that measures to combat liquid waste (wastewater) and gaseous waste (gas-smoke emissions) were considered by us in § 3 and 4 of this chapter.[...]
Gas mixtures are analyzed for the content of the main components. Natural and industrial gas mixtures, as well as the air of industrial premises, are analyzed. Industrial gas mixtures include: flammable gas mixtures (natural, generator, blast furnace gases), industrial mixtures (nitrogen-hydrogen mixture in ammonia synthesis, gas from pyrite furnaces containing sulfur dioxide), exhaust gases (flue gases containing nitrogen, carbon dioxide, water vapor, etc.). The air of industrial premises contains impurities of gases characteristic of this production. Gas analytical methods are used to control the composition of air emitted into the atmosphere from industrial premises. Most often the composition gas mixtures analyzed by gasometric and methods and by the absorption of mixture components by liquid absorbers. The volume of the absorbed component is determined by the difference in the measured volumes before and after absorption.[...]
A neutral pure solution of wood vinegar powder is evaporated and dried in a spray dryer 15. This is a brick cylindrical shaft with a domed vault. It contains three horizontal hearths, located one above the other. Adjacent to the dryer is a furnace 16, in which coal waste and charcoal generator gas are burned. Flue gases from the firebox go up the chimney and enter the dryer shaft under its roof. A solution of wood vinegar powder is supplied from receivers 8 by a centrifugal pump to the upper part of the shaft through spray nozzles. Small droplets of wood vinegar powder solution enter the current of hot flue gases; the water evaporates from them, and the resulting grains of wood vinegar powder accumulate on the upper floor of the dryer. Along the axis of the dryer there is a vertical axis, to which scrapers are attached at the top, cleaning the walls of the shaft, and below - rods with scrapers that clean the hearths; under the lowest hearth on the axis there is a toothed gear coupled with a gearbox driven by an electric motor.[...]
The prevention of groundwater pollution is facilitated by general measures: 1) creation of closed industrial water supply and sewerage systems; 2) introduction of production with zero-discharge technology or with a minimum amount of wastewater and other waste; 3) improvement of wastewater treatment; 4) isolation of communications from wastewater; 5) elimination or cleaning of gas and smoke emissions at enterprises; 6) controlled, limited use of pesticides and fertilizers in agricultural areas; 7) deep burial of particularly harmful wastewater that does not have economically justified methods of treatment or disposal; 8) creation of water protection zones in areas of groundwater development with the establishment of strict rules for economic and construction activities there. [...]
Depending on existing meteorological conditions (air humidity, solar radiation), a variety of reactions between air pollutants occur in the atmosphere. Many harmful substances are thus partially removed from the atmospheric air (for example, dust, 502, H02, HP), but harmful products can also be formed. In European conditions, where flue gases containing sulfur dioxide are emitted together with soot and ash, the possibility of the formation of wet sulfuric acid surfaces on soot and ash particles should be taken into account. Another mechanism for the formation of smog in Los Angeles (see page 14) is isolefins and nitrogen oxides from car exhaust gases under the influence of oxygen under intense solar radiation. In this case, with the simultaneous formation of short-lived radicals and ozone, a variety of sharp-smelling and eye-irritating aldehydes and peroxides arise, for example, peroxyacetyl nitrate CH3C000K02, also obtained artificially in an experiment to simulate the conditions of smog formation. [...]
Analysis of the patterns of particle sedimentation processes in inhomogeneous aerosols that we encounter in the atmospheric air is significantly complicated due to the diversity of meteorological conditions, particle sizes and shapes. When a dust cloud reaches the earth's surface, the settling speed of the particles is determined by their mass and size. The concentration of particles in the surface layer of air depends on the absolute mass of the emission, and not on their concentration in the gases of chimneys. The settling rate of particles and their concentration in the ground layer of air can be changed by increasing or decreasing the height of the chimneys. As a result of measurements of the amount of settled dust, data have been obtained to determine the settling rate of aerosol particles, but these measurements do not allow the assessment of pollution, which causes a decrease in visibility (Johnston, 1952).[...]
In Fig. Figure 40 shows a diagram of coal regeneration. The spent coal enters the bunker for partial dehydration (within 10 minutes of residence, the pulp moisture drops to 40%). Then, through a screw conveyor, the dehydrated coal is supplied for regeneration proper to the six-hearth furnace shown in Fig. 26. In order to avoid deterioration in the quality of coal, it is recommended that the regeneration process be carried out at a temperature of at least 815° C. According to the operational data of the treatment plant near the lake. Tahoe, the temperature on the last hearths is maintained at 897° C. To intensify the regeneration process, steam is supplied at the rate of 1 kg per 1 kg of dry coal. The six-pod furnace runs on natural gas. Flue gases are dedusted in a wet scrubber. Coal from the furnace enters the cooling tank. With the help of pumps and a system of nozzles on the suction pipeline, the coal is in continuous movement, which speeds up the cooling process. The cooled coal is collected in bunkers, from there it is fed into a tank for preparing coal pulp. Fresh coal is supplied to the same tanks to replenish losses.[...]
The second complex should include additional sanitary and health measures and restrictions prescribed in the absence of natural protection from chemical pollution.
FLUE GASES
FLUE GASES
(Flue gases) - gaseous combustion products.
Samoilov K. I. Marine Dictionary. - M.-L.: State Naval Publishing House of the NKVMF of the USSR, 1941
See what “FLUGE GASES” is in other dictionaries:
Flue gases- Gases formed in emission sources during the combustion of organic substances Source: OND 90: Guidelines for the control of sources of air pollution ... Dictionary-reference book of terms of normative and technical documentation
flue gases- Organic fuel combustion products. origin, emanating from the working space of heated metallurgical plants. units. Topics: metallurgy in general EN fume ...
flue gases- fuel combustion products of organic origin, leaving the working space of heated metallurgical units; See also: Gases furnace gases gases in metals waste gases inert gases ...
flue gases- flue gases... Dictionary of chemical synonyms I
wet flue gases- - [A.S. Goldberg. English-Russian energy dictionary. 2006] Energy topics in general EN wet flue gases ... Technical Translator's Guide
recirculating flue gases- - [A.S. Goldberg. English-Russian energy dictionary. 2006] Energy topics in general EN recycled flue gas es ... Technical Translator's Guide
composition-averaged flue gases- - [A.S. Goldberg. English-Russian energy dictionary. 2006] Topics of energy in general EN average flue gases ... Technical Translator's Guide
Gases in technology are used mainly as fuel; raw materials for chemical industry: chemical agents in welding, gas chemical heat treatment metals, creating an inert or special atmosphere, in some... ...
I Gases (French gaz; the name was proposed by the Dutch scientist J. B. Helmont state of aggregation a substance in which its particles are not connected or very weakly connected by interaction forces and move freely, filling the entire ... ... Great Soviet Encyclopedia
chimneys- a structure for creating draft and removing gaseous products of fuel combustion from various metallurgical furnaces and boiler units. In small furnaces, chimneys are designed to create natural draft, under the influence of... ... Encyclopedic Dictionary of Metallurgy
The theoretically required amount of air for combustion of generator, blast furnace and coke oven gases and their mixtures is determined by the formula:
V 0 4.762/100 *((%CO 2 + %H 2)/2 + 2 ⋅ %CH 4 + 3 ⋅ %C 2 H 4 + 1.5 ⋅ %H 2 S - %O 2), nm 3 / nm 3, where % is by volume.
Theoretically required amount of air for combustion natural gas:
V 0 4.762/100* (2 ⋅ %CH 4 + 3.5 ⋅ %C 2 H 6 + 5 ⋅ %C 3 H 8 + 6.5 ⋅ %C 4 H 10 + 8 ⋅ %C 5 H 12), nm 3 /nm 3, where % is by volume.
The theoretically required amount of air for combustion of solid and liquid fuels:
V 0 = 0.0889 ⋅ %C P + 0.265 ⋅ %H P – 0.0333 ⋅ (%O P - %S P), nm 3 /kg, where % is by weight.
Actual quantity of combustion air
The required completeness of combustion when burning fuel with the theoretically required amount of air, i.e. at V 0 (α = 1), can only be achieved if the fuel is completely mixed with the combustion air and is a ready-made hot (stoichiometric) mixture in gaseous form. This is achieved, for example, when burning gaseous fuels using flameless combustion burners and when burning liquid fuels with their preliminary gasification using special burners.
The actual amount of air for combustion of fuel is always greater than the theoretically required one, since in practical conditions some excess air is almost always required for complete combustion. The actual amount of air is determined by the formula:
V α = αV 0, nm 3 /kg or nm 3 /nm 3 fuel,
where α is the excess air coefficient.
With the flare combustion method, when fuel and air are mixed during the combustion process, for gas, fuel oil and pulverized fuel the excess air coefficient is α = 1.05–1.25. When burning gas, previously completely mixed with air, and when burning fuel oil with preliminary gasification and intensive mixing of fuel oil gas with air, α = 1.00–1.05. With the layer method of burning coal, anthracite and peat in mechanical furnaces with continuous fuel supply and ash removal - α = 1.3–1.4. During manual maintenance of furnaces: when burning anthracite α = 1.4, when burning hard coalsα = 1.5–1.6, when burning brown coals α = 1.6–1.8. For semi-gas fireboxes α = 1.1–1.2.
Atmospheric air contains a certain amount of moisture - d g/kg of dry air. Therefore, the volume of moist atmospheric air required for combustion will be greater than calculated using the above formulas:
V B o = (1 + 0.0016d) ⋅ V o, nm 3 /kg or nm 3 /nm 3,
V B α = (1 + 0.0016d) ⋅ V α, nm 3 /kg or nm 3 /nm 3.
Here 0.0016 = 1.293/(0.804*1000) is the conversion factor for weight units of air moisture, expressed in g/kg of dry air, into volume units - nm 3 of water vapor contained in 1 nm 3 of dry air.
Quantity and composition of combustion products
For generator, blast furnace, coke oven gases and their mixtures, the quantity individual products complete combustion during combustion with an excess air coefficient equal to α:
Amount of carbon dioxide
V CO2 = 0.01(%CO 2 + %CO + %CH 4 + 2 ⋅ %C 2 H 4), nm 3 / nm 3
Amount of sulfur dioxide
V SO2 = 0.01 ⋅ %H 2 S nm 3 /nm 3 ;
Amount of water vapor
V H2O = 0.01(%H 2 + 2 ⋅ %CH 4 + 2 ⋅ %C 2 H 4 + %H 2 S + %H 2 O + 0.16d ⋅ V α), nm 3 /nm 3,
where 0.16d V B á nm 3 /nm 3 is the amount of water vapor introduced by moist atmospheric air at its moisture content d g/kg of dry air;
The amount of nitrogen transferred from gas and introduced with air
The amount of free oxygen introduced by excess air
VO2 = 0.21 (α - 1) ⋅ VO, nm 3 /nm 3.
The total amount of combustion products of generator, blast furnace, coke oven gases and their mixtures is equal to the sum of their individual components:
V dg = 0.01 (%CO 2 + %CO + %H 2 + 3 ⋅ %CH 4 + 4 ⋅ %C 2 H 4 + 2 ⋅ %H 2 S + %H 2 O + %N 2) + + VO (α + 0.0016 dα - 0.21), nm 3 /nm 3.
For natural gas, the amount of individual products of complete combustion is determined by the formulas:
V CO2 = 0.01(%CO 2 + %CH 4 + 2 ⋅ %C 2 H 6 + 3 ⋅ %C 3 H 8 + 4 ⋅ %C 4 H 10 + 5 ⋅ %C 5 H 12) nm 3 / nm 3;
V H2O = 0.01(2 ⋅ %CH 4 + 3 ⋅ %C 2 H 6 + 4 ⋅ %C 3 H 8 + 5 ⋅ %C 4 H 10 + 6 ⋅ %C 5 H 12 + %H 2 O + 0.0016d V α) nm 3 /nm 3 ;
V N2 = 0.01 ⋅ %N 2 + 0.79 V α, nm 3 /nm 3;
VO2 = 0.21(α - 1) VO, nm 3 /nm 3.
Total amount of natural gas combustion products:
V dg = 0.01(%CO 2 + 3 ⋅ %CH 4 + 5 ⋅ %C 2 H 6 +7 ⋅ %C 3 H 8 + 9 ⋅ %C 4 ⋅H 10 + 11 ⋅ %C 5 H 12 + %H 2 O + + %N 2) + VO (α + 0.0016dα - 0.21), nm 3 /nm 3.
For solid and liquid fuels, the number of individual products of complete combustion:
V CO2 = 0.01855 %C P, nm 3 /kg (hereinafter, % is the percentage content of elements in the working gas by mass);
V SO2 = 0.007% S P nm 3 /kg.
For solid and liquid fuels
V H2O CHEM = 0.112 ⋅ %H P, nm 3 /kg,
where V H2O CHIM is water vapor formed during the combustion of hydrogen.
V H2O FUR = 0.0124%W P, nm 3 /kg,
where V H2O FUR is water vapor formed during the evaporation of moisture from the working fuel.
If steam is supplied to atomize liquid fuel in the amount of W STEAM kg/kg of fuel, then the value of 1.24 W STEAM nm 3 /kg of fuel must be added to the volume of water vapor. The moisture introduced by atmospheric air at a moisture content of d g/kg of dry air is 0.0016 d V á nm 3 /kg of fuel. Therefore, the total amount of water vapor:
V H2O = 0.112 ⋅ %H P + 0.0124 (%W P + 100 ⋅ %W PAR) + 0.0016d V á, nm 3 /kg.
V N2 = 0.79 ⋅ V α + 0.008 ⋅ %N P, nm 3 /kg
VO2 = 0.21 (α - 1) VO, nm 3 /kg.
General formula for determining combustion products of solid and liquid fuels:
V dg = 0.01 + VO (α + + 0.0016 dα - 0.21) nm 3 /kg.
The volume of flue gases when burning fuel with the theoretically required amount of air (VO nm 3 /kg, V O nm 3 /nm 3) is determined according to the given calculation formulas with an excess air coefficient of 1.0, while the combustion products will contain no oxygen.
