RU2321759C2 - Method to reduce content of harmful matters in discharge gases of transport heat engines operating in confined spaces - Google Patents

Abstract

FIELD: mechanical engineering; transport engineering.

SUBSTANCE: invention relates to heat engines of transport vehicle and special equipment operating of hydrocarbon fuel, it can be used to reduce content of toxic components in exhaust gases to tolerable concentrations according to sanitary standards at operation in confined spaces, for instance, in underground mining, green houses, underground railways at repairs using special machinery. To reduce harmful exhausts, complex of operations is implemented for acting both on process of fuel combustion in cylinders of engine and on content of harmful matters in exhaust gases discharged into atmosphere by additional of ecological admixture into fuel, for instance, mixture of ferrum acetylacetone (10-90% by weight) and ferrocene (the remainder), contact cleaning and cooling of exhaust gases by water solution of hydroxides of alkaline and/or alkaline-earth metal, recirculation of part of cooled and cleaned exhaust gases to engine intake with preliminary enrichment of exhaust gases with oxygen by contact with hard oxygen carrier discharge of remaining amount of exhaust gases into atmosphere. Degree of recirculation of exhaust gases is set depending on load of heat engine with limiting of air getting into intake system.

EFFECT: reduced concentration of harmful matters in discharge gases to level maximum tolerable according to requirements of sanitary standards.

1 dwg

Description

The invention relates to heat engines (TD) of vehicles (TS) and special equipment operating on liquid hydrocarbon fuel, and can be used to reduce the content of toxic components in their exhaust gases (exhaust gas) to the maximum permissible concentrations in accordance with the requirements of sanitary standards at work in conditions of limited volumes, for example, in workings during underground mining of minerals, in greenhouses in the course of work on the care of plants, in the subway in the production of repair work bot using special equipment.

A known method of reducing the content of harmful emissions from exhaust gas TD, described in [1]. In this method, the exhaust gas is brought into contact with an alkali solution (pH 7.5-8.0) dispersed in the exhaust gas stream in the form of droplets, and then the resulting mixture is dispersed in the volume of an aqueous alkali solution with controlled concentration of the active component-absorber, level and temperature solution with the formation of foam, resulting in the cooling of the exhaust gas and their purification from solid and gaseous harmful substances. This method allows you to reduce by 35-90% (depending on the type of harmful substance) the amount of harmful emissions from exhaust gases that are removed into the atmosphere, without affecting the engine's operating process. The main disadvantage of this method is the increased dimensions of the system of devices for its implementation due to the need to create concentrated alkali and water reserves on the vehicle to compensate for their consumption as a result of chemical binding and evaporation.

In [2], methods are described for reducing exhaust toxicity by affecting the engine’s working process by:

- recirculation of the exhaust gas from the exhaust to the engine inlet;

- preliminary preparation of fuel for burning by the introduction of environmental additives in its composition in concentrations of 0.01 ... 0.025% by weight.

It is known that recirculation is used to combat nitrogen oxides, and its main disadvantage is an increase in the emission of dispersed particles (mainly carbon black) and carbon monoxide (CO) as a result of a decrease in the oxygen concentration in a fresh charge, and the introduction of additives into the fuel composition, providing a reduction in emissions nitrogen oxides and soot, slightly affects the emission of other toxic components (hydrocarbons, aldehydes, etc.). As a rule, these methods are used separately and the problem of reducing exhaust toxicity is not completely solved. The analysis shows that in order to achieve acceptable results, an integrated approach to the problem of reducing harmful emissions is needed, combining both measures to optimize fuel combustion processes and measures to clean the exhaust components that are removed into the atmosphere from the toxic components contained in them.

There is a method of reducing harmful emissions from exhaust gases of heat engines described in [3] and being the closest analogue of the present invention, according to which an additive is introduced into the fuel before burning, and a mixture of iron acetylacetonate is used as an additive to the fuel (10-90 wt.%) and ferrocene (rest). The disadvantage of this method is the inability to achieve the content of toxic components in the exhaust gas that meets the requirements of sanitary standards.

The challenge facing the invention is to reduce the content of solid and gaseous toxic components in the exhaust gas of the heat engine of the vehicle to the level of maximum permissible concentrations (MPC) in atmospheric air.

The solution to the problem is assumed by implementing a set of measures to influence both the process of fuel combustion in the engine cylinders and the composition of the exhaust gases removed to the atmosphere by implementing, along with the addition of an environmental additive to the fuel, for example, a mixture of iron acetylacetonate (10-90% by weight) and ferrocene (rest), contact cleaning and cooling of the exhaust gas with an aqueous solution of an absorbent based on alkali and / or alkaline earth metal hydroxides, for example NAOH or KOH, and recirculating part of the cooled exhaust gas to the engine inlet before lnym their enrichment with oxygen, obtained by contacting the exhaust gas with a solid based kislorodonositelem superoxides of alkali or alkaline earth metal, and removing the remaining quantity of the exhaust gas into the atmosphere. The degree of exhaust gas recirculation is set depending on the load on the TD, limiting the flow of air into the intake system.

New in the claimed invention is the integrated implementation of operations to reduce the content of harmful substances in the exhaust gases of exhaust vehicles engines (environmental additives to fuel, contact cleaning and cooling the exhaust gas with an aqueous absorbent solution, recirculating part of the cooled exhaust gas to the engine inlet with their preliminary enrichment with oxygen by contact with solid oxygen carrier and removal of the remaining amount of exhaust gas into the atmosphere) performed in a sequence not previously used in the art.

These new features are not identified from the existing level of technology, which allows us to conclude that the claimed invention meets the criterion of "inventive step".

The proposed method can be implemented in a device, a diagram of which is shown in the drawing.

The device comprises an engine 1 with intake and exhaust systems, an additive reserve tank 2 and a fuel tank 3 connected to the suction port of the fuel priming pump 4, wherein the additive reserve tank 2 is connected through the metering device 5, and the discharge port of the pump 4 is connected to the standard engine fuel system 1. In the exhaust system of engine 1, a contact liquid cooler-neutralizer 6 (KOH) and an exhaust gas reactor-neutralizer (RNG) 7 are installed, in which to clean the exhaust gas from gaseous harmful substances and enrich their ki a solid oxygen carrier is used by the sulphide. KOH 6 through its input through the locking device 8 is connected to the engine 1, and the output through the locking device 9 and 10 to the input of the RNG 7. The output of the RNG 7 through the locking device 11 and 12 is in communication with the intake system of the engine 1 and the atmosphere, respectively. In addition, the exhaust system to the shut-off device 8 is in communication with the atmosphere through the shut-off devices 13 and 14, while sections of pipelines between the shut-off devices 9-10 and 13-14 are interconnected.

The method is as follows. The fuel from the tank 3 after dosed introduction of an environmental additive into it through the metering device 5 by the pump 4 is sent to the standard fuel system of the engine 1, which delivers the resulting mixture of fuel and additives to the engine cylinders in an amount corresponding to the engine load. During the combustion process, the mixtures contained in the additive decompose into intermediate radicals that have lower activation energy and, accordingly, ignite at a lower temperature, which helps to reduce the combustion temperature of the fuel and reduce the rate of formation of nitrogen oxides (NO _x ), carbon black (C) and oxide carbon (CO). Next, the exhaust gases formed during the combustion of the fuel mixture with the additive are fed through KON 6 to the KOH 6 through the open shutoff valve 8 (with the shutoff valve 13 closed), where, as a result of contact with an aqueous solution of a refrigerant-absorbent, which can be used as natural water, containing calcium and magnesium ions and hydroxyl groups, as well as aqueous solutions with an alkaline reaction, they are cooled and purified by 30-40% from NO _x , as well as 80-95% from carbon black, benz (α) pyrene, sulfur oxides, unburned hydrocarbons and aldehydes. Exhaust gases that have been contacted through open shutoff bodies 9, 10 and 14 are sent partly to the atmosphere and partly to the RNG 7. In the RNG, cooled, moistened and purified exhaust gases are brought into contact with a solid oxygen carrier, for example, potassium superoxide (CaO ₂ ), as a result of which by reactions:

2KaO CO ₂ + ₂ = Ca ₂ CO ₃ 1 _^1/2 O _2;

H ₂ O + ₂ = 2KaO 2KaON + a 1 _^1/2 O ₂

oxygen is released, which is mixed with the components of the exhaust gas (nitrogen, unused oxygen, carbon, carbon monoxide and carbon dioxide, nitrogen dioxide). The resulting mixture through the open locking element 11 with the closed 12 is sent to the intake system of the engine 1, where it is mixed with air taken from the atmosphere and used to burn the fuel mixture with the additive in the engine cylinders.

An increase in CO, C, and CH emissions, a decrease in power, and a decrease in fuel economy of the engine due to a decrease in the oxygen concentration in the fresh charge, inherent in exhaust gas recirculation as a way to reduce the emission of explosives, is prevented by enriching the bypassed part of the exhaust gas with oxygen, and lowering the temperature level in the cylinders the engine during fuel combustion is provided due to the additive to the fuel and cooling the bypassed part of the exhaust gas. The degree of exhaust gas recirculation is set depending on the load on the TD, limiting the flow of air into the intake system.

Thus, with the integrated implementation of the operations described in the description of the algorithm, the concentration of harmful emissions in the exhaust gases of the engine engines is reduced to the maximum permissible in accordance with the requirements of sanitary standards, which confirms the solution of the problem and allows us to conclude that the claimed invention meets the criterion of "industrial applicability" .

Bibliography

1. RF patent No. 2027464 "System for purification of exhaust gases of internal combustion engines", publ. 01/27/1995 g.

2. Kulchitsky A.R. Toxicity of automobile and tractor engines. - M.: Academic Prospect LLC, 2004., 400 p.

3. RF patent №2151168, IPC С10L 1/18 "Environmental additive to diesel fuel", publ. in 2000

Claims (1)

A method of reducing harmful emissions from exhaust gases of thermal engines of vehicles operating in limited volume conditions is that an additive is introduced into the fuel before burning, and a mixture of iron acetylacetonate (10-90 wt.%) Is used as an additive to the fuel and ferrocene (the rest), characterized in that the entire volume of exhaust gases generated during the combustion of the fuel mixture with the additive is subjected to contact treatment with an aqueous solution of an absorbent based on alkali and / of alkaline earth metals, part of the treated exhaust gas is sent to the engine intake system with their preliminary enrichment with oxygen due to contact with a solid oxygen carrier based on alkali metal or alkaline earth metal superperoxides, and the remaining part of the exhaust gas is removed into the atmosphere, while the degree of exhaust gas recirculation is determined as from the load on the heat engine, limiting the flow of air into the intake system of the engine.