RU2474703C1 - Method of complex treatment of gaseous products of combustion - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: method of treatment of gaseous products of combustion consists in cooling gaseous products of combustion till condensate temperature, separation of formed liquid and its disposal, first fine soot particles and aerosols are separated from gaseous products of combustion, gaseous products of combustion are cooled till values of temperature, pressure and specific volume less than critical forming liquid phase of hydrocarbons and separating it, remaining gaseous products of combustion are neutralised forming the phase of water vapours, then gaseous products of combustion are cooled till water solid phase that is separated, then residuals of gaseous products of combustion are cooled till solid phase of carbon dioxide that is separated from combustion products, note that hydrocarbon liquid phase, solid phases of water and carbon dioxide are disposed, and the residuals of gaseous products of combustion are released into the atmosphere.

EFFECT: increase of gaseous products of combustion purification degree.

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Description

The invention relates to a method for processing gaseous products of combustion, and more particularly, to a method for cleaning such products and can be used for cleaning systems from toxic components of exhaust gases and exhaust industrial ventilation emissions, in particular for cleaning exhaust gases of internal combustion engines.

A known method for the catalytic purification of exhaust gases from nitrogen oxides at elevated temperatures using ammonia and using a catalyst containing an active component in the form of industrial waste and clay, the sewage sludge from thermal power plants generated by washing boiler units is used as the active component, and the catalyst additionally contains fuel oil. (RF patent 2111045, IPC B01D 53/86, publ. 05.20.1998., Sukharnikov A.E., Mahotkin A.F., Shamsivaleev M.G., Biryukov V.V., Shkedov V.M., Ustimets A .A., Khayrullin RG, Budilkin VV "Method for the catalytic purification of gases from nitrogen oxides").

The disadvantage of this method is the low degree of quality of purification of gaseous products of combustion.

A known method of purification of gaseous products of combustion, which consists in cooling the gaseous products of combustion to a condensation temperature, separating the formed liquid and disposing of it (RF Patent No. 2258148, IPC F01N 3/04, published. 08/10/2005. Bruzzo Vital "Method and device for cleaning gaseous products combustion ").

The disadvantage of this method is the low degree of quality of exhaust gas purification.

This technical solution is selected by the authors as a prototype.

The technical result is to increase the degree of purification of gaseous products of combustion.

The technical result is achieved by the fact that in the method of purification of gaseous products of combustion, which consists in cooling gaseous products of combustion to a condensation temperature, separating the formed liquid and disposing of it, fine particles of soot and aerosols are initially separated from the gaseous products of combustion, and the gaseous products of combustion are cooled to temperatures , pressure and specific volume less than critical, forming the liquid phase of hydrocarbons and separating it, the remaining gaseous products of combustion n they are neutralized by forming a phase of water vapor in them, then the gaseous products of combustion are cooled to a solid phase of water, which is separated, then the remaining gaseous products of combustion are cooled to a solid phase of carbon dioxide, which is separated from the products of combustion, and the liquid phase of hydrocarbons, solid phases of water and dioxide carbon is disposed of, and the remaining gaseous products of combustion are released into the atmosphere.

The initial separation of fine particles of soot and aerosols can reduce the solids content in the combustion products and facilitate the elimination of harmful gaseous products of combustion. Hydrocarbon condensation allows the formation of liquid hydrocarbons and their easy separation. Neutralization can reduce the content of nitrogen oxides in the products of combustion. Crystallization of water vapor allows the formation of ice and to separate it from gaseous products of combustion. Crystallization of carbon dioxide allows the formation of dry ice and its separation from gaseous products of combustion.

The method of purification of gaseous products of combustion from harmful components is implemented through the following technological operations:

- cooling of exhaust gases;

- separation of fine particles of soot and aerosols;

- condensation of hydrocarbons C _n H _m ;

- neutralization of nitrogen oxides NO _x ;

- crystallization of water vapor H ₂ O;

- crystallization of carbon dioxide CO ₂ .

When implementing this method, the gaseous products of combustion are pre-cooled. The cooled gas is passed, for example, through a trap of fine particles of soot and aerosols, resulting in the purification of exhaust gases from solid particles. Then the gaseous products of combustion are cooled and compressed to less than critical values of temperature, pressure and specific volume. As a result, unburned hydrocarbons C _n H _m pass from the gaseous phase to the liquid. The critical parameters of hydrocarbons are presented in table 1. The formed liquid is discharged from gaseous products of combustion.

Table 1 Name of gas Critical pressure, MPa Critical temperature ° C Density at critical pressure and temperature, kg / m ^-1 Methane CH ₄ 4.64 -82.5 162 Ethane C ₂ H ₆ 4.86 32.1 200 Propane C ₃ H ₈ 4.07 96.8 226 Butane C ₄ H ₁₀ 3,55 152.1 228 Pentane C ₅ H ₁₂ 3.3 197,2 232

After separation of the liquid phase of the hydrocarbons, the nitrogen oxides NO _{x are} neutralized. The neutralization is carried out, for example, by adding ammonia NH _{3 to the} exhaust gas stream. In this case, ammonia NH ₃ reacts with OH to form NH ₂ ; NO reacts with NH ₂ to form water and N ₂ (or N ₂ O, which also ultimately leads to the formation of N ₂ ). The most important reaction elements of this process are:

NH ₃ + H → NH ₂ + H ₂

NH ₃ + O → NH ₂ + OH

NH ₃ + OH → NH ₂ + H ₂ O

NH ₂ + OH → NH + H ₂ O

NH ₂ + O ₂ → NHO + OH

NH ₂ + NH ₂ → NH ₃ + NH

NH ₂ + NO → N ₂ + H ₂ O

NH ₂ + OH → N ₂ H + OH

NH ₂ + HNO → NH ₃ + NO

HNO + H → NH ₃ + OH

HNO + M → H + NO + M

HNO + OH → NO + H ₂ O

N ₂ H + M → N ₂ + H + M

N ₂ H + NO → N ₂ + HNO

N ₂ H + OH → N ₂ + H ₂ O

Next, crystallize water vapor H ₂ O. The gas is cooled to the crystallization temperature of water. Water passes from the gaseous phase to the solid. Formed ice crystals are removed from the gaseous products of combustion. Next, crystallization of carbon dioxide CO _{2 is} carried out. The gas is cooled to a crystallization temperature of carbon dioxide CO ₂ and compressed. As a result, carbon dioxide passes into the solid phase. The formed crystals of carbon dioxide (dry ice) are removed from the combustion products. The crystallization temperatures of water H ₂ O and carbon dioxide CO _{2 are} presented in table 2.

table 2 Name of gas Crystallization Temperature, ° C Water vapor H ₂ O 0 Carbon dioxide CO ₂ -57

After the elimination of all harmful components of the combustion products, the purified gas is released into the atmosphere. Collected liquid hydrocarbons, ice and dry ice are disposed of.

The proposed method of purification of gaseous products of combustion allows to eliminate up to 98% of all harmful substances and ensure environmental safety of internal combustion engines and other power plants.

Claims (1)

The method of purification of gaseous products of combustion, which consists in cooling the gaseous products of combustion to a condensation temperature, separating the formed liquid and disposing of it, characterized in that the method initially separates fine particles of soot and aerosols from the gaseous products of combustion, and the gaseous products of combustion are cooled to temperatures pressure and specific volume is less than critical, forming the liquid phase of hydrocarbons and separating it, the remaining gaseous products of combustion are neutralized, I have the phase of water vapor in them, then the gaseous products of combustion are cooled to the solid phase of the water that is separated, then the residues of the gaseous products of combustion are cooled to the solid phase of the carbon dioxide, which is separated from the products of combustion, and the liquid phase of hydrocarbons, the solid phases of water and carbon dioxide are utilized and the remnants of the gaseous products of combustion are released into the atmosphere.