RU2125168C1 - Waste gas cleaning method - Google Patents

Abstract

FIELD: mechanical and transport engineering; cleaning of exhaust gases of vehicles powered by internal combustion heat engines, waste gases of industrial enterprises such as incinerator plants, heat power generating plants. SUBSTANCE: deep after-burning of noncombusted toxic components in exhaust gases is carried out half of flame for instance, in flame of combusted gas (propane) of gas burner(s) with simultaneous application of storage electric field with E ≥ I sq/cm. onto flame. Then wet cleaning of waste gases is carried out after electric flame treatment, for instance, by delivering alkaline aerosols to fix gas dioxides (SO₂, NO₂, CO₂ and others) to form acid fumes with simultaneous neutralization of acid fumes by water-alkali aerosol and utilize free remnants in detachable reservoir. EFFECT: enhanced cleaning of waste gases. 2 cl, 2 dwg

Description

 The invention relates to methods for purifying exhaust gases from toxic components (unburned hydrocarbons, hydrogen sulfides, carbon monoxide, soot, smoke, odors, etc.) and can be widely used on all types of vehicles with heat engines, especially diesel engines (motor vehicles, watercraft, river, air), and can also be used for cleaning atmospheric emissions of harmful industries (thermal power plants, cable, chemical, metallurgical industries), and can also be used in waste landfill advanced technologies.

 There are various methods of purification of exhaust gases, for example, chemical, thermal, catalytic (see the book. Bernadiner MN "Fire processing and disposal of industrial waste", M., 1990, p. 28 - analogues).

 A known chemical (catalytic) method for cleaning exhaust gases by passing toxic gases through a system of surfaces coated with a chemical catalyst, such as platinum (for example, Russian patent N 2023179). The disadvantages are the high cost and complexity of implementing the method, in the inhibition of the main gas flow due to the high aerodynamic resistance of platinum grids, the need for preliminary treatment of exhaust gases and solid particles, because of which the catalytic method is inoperative.

 A known method of electro-filtering soot and particulate matter from exhaust gases on one of the electrodes, followed by the systematic removal of sediment (see Japan application N 63-13007, publ. 23.03.88 MKI F 01 N 3/08; AS USSR N 601854, N 1212490, etc.).

 The disadvantages of this method are the unreliability of its implementation due to the systematic "shorting" of the electrodes with a conductive layer of soot, in low productivity.

 The known vortex method of purification of solid particles, soot from exhaust gases, consisting in the separation of solid particles by mechanical rotation of the gas stream (Prince M.N. Bernadiner "Fire processing and disposal of industrial waste", M., 1990).

 The problem of this method is significant energy consumption and poor cleaning of gases from smoke.

 Known chemical methods of neutralizing exhaust gas oxides by treating them with an alkaline liquid in combination with a catalytic neutralization method (Russian patent N 2023177, 1994; MKI F 01 N 3/02). The disadvantages are the difficulty in implementing the method (especially for ICE) due to the creation of significant aerodynamic resistance to the flow of exhaust gases, in the short term of failure-free operation due to the rapid clogging with soot of porous alkaline capsules.

 There is a known thermal method for burning toxic components of exhaust gases by passing them through a jet of low-temperature plasma (AS USSR N 1460368, 1989, MKI F 01 N 3/08). The essence of the prototype method is the thermal ionization of the toxic components of the exhaust gases and the intensification of the processes of their afterburning and neutralization. The disadvantage of the prototype method is the incomplete purification of exhaust gases due to the low temperature and poor ionization of the flame and the exhaust gas flow, low energy efficiency due to excessive fuel consumption.

 The purpose of the invention is to increase the efficiency of purification of exhaust gases of any degree of contamination and to improve the prototype method.

 The essence of this invention consists in an experimentally proven method of intensifying the process of burning a flame by applying a strong electric field with E≥1 kV / cm.

 One of the objectives of the present invention is the application of the described method of controlling the combustion of a flame to efficiently clean toxic flue gases.

 We explain the essence of the invention - the proposed method of purification of exhaust gases is carried out by their fire treatment with low-temperature plasma while simultaneously supplying an oxidizing agent to the combustion zone and simultaneously applying a strong electric field with a voltage of E≥1 kV / cm, for example, along the flame plume, with electric fire afterburning the exhaust gas is carried out in a thermostatic chamber with a diameter and volume sufficient for deep afterburning of the toxic components of the exhaust gas, and regulate the vapor flame plume (height; volume; temperature) and the parameters of the mentioned electric field (intensity; frequency; shape; electron emission current; distance between electrodes) depending on the intensity and composition of the exhaust gas being cleaned, for example, by measuring toxic components after their electric firing, comparison with a given level of cleaning and the subsequent programmed change in the parameters of the flame and the electric field, after which they carry out wet aerosol treatment of the exhaust gases with an aqueous alkaline liquid, and for example, electrostatically sprayed into the exhaust gas stream, for example, perpendicular to the stream, after which the remaining acid condensate is condensed and collected in an easily removable container, and the purified exhaust gas is released into the atmosphere, and the flow rate and aerosol composition are regulated, for example, by changing the potential from the source electric field depending on the intensity and composition of the exhaust gases.

 The implementation of the proposed method is shown on the example of an exhaust gas purification device (Fig. 1, 2). This device contains (Fig. 1) a source of contaminated exhaust gases 1, for example, an internal combustion engine (diesel), an intake manifold 2, an electric fire gas treatment chamber 3, made, for example, cylindrical, refractory, electrically isolated, an exhaust manifold 4; electrical insulator 5, for example, in the form of a porcelain cylinder; heat-resistant coaxial electrode 6 with a mesh electrode 7 in the flame direction, made also of a heat-resistant, corrosion-resistant alloy, for example, based on a nickel-chromium alloy, through a terminal 8 connected to one of the outputs of the high-voltage voltage converter 9 with a control system 10, and along the power supply circuit connected to the power supply unit 11, for example, an industrial network 220/380 V, or to an on-board electric generator; the gas afterburner 3 is also provided with a gas burner 12 connected through a fuel line and an electromagnetic valve 13 to a gas cylinder 14, for example, with propane; moreover, the electromagnetic valve is connected to the power transducer 15, for example, a magnetic power amplifier with a control system 16, and the device is supplemented by a system for measuring and monitoring the intensity and composition of the exhaust gases 17 before and after electroplasma treatment (in Fig. 1 sensors 17 are shown only after processing), and also microprocessor 18, the input of which is connected to sensors for measuring and monitoring the exhaust gases 17, and its outputs are connected to the inputs of control systems 10, 16.

 The device also has a device for electric spark ignition of the flame torch 19 (not shown in Fig. 1), as well as an oxidizer (air) supply system to the chamber (not shown in Fig. 1). The crude exhaust gases are indicated in FIG. 1 at 19, and purified gases at 20. FIG. 1 intake air - V, exhaust gases - exhaust gas.

 In FIG. 2 shows a device for implementing a finishing operation for wet cleaning of exhaust gases. The device consists of an inlet pipe 21, into which the off-gas 20, which has undergone electric firing treatment, enters a second chamber 22 with fine spray nozzles 23, a distributor 24, a pump 25, a tank 26 with an alkaline water emulsion 27. The spray aerosol is indicated in FIG. 2 at 28.

 The device (Fig. 2) also contains an outlet pipe (29) for discharging completely purified exhaust gases (30) into the atmosphere, a steam condenser (31) with a capillary wick (32), a collection tank (33) for condensate (34), and a tube ( 35) with a tap for periodic removal of condensate 34.

The proposed method is implemented in the described devices as follows:
First, the crude exhaust gases 19 are supplied from their source 1, for example, diesel, through the intake manifold 2 to the electric fire treatment chamber 3, after which gas is supplied from the cylinder 14 through the valve 13 to the nozzle 12 inside the chamber 3, then it is ignited by the electric spark method to form a flame 19, through which the exhaust gases 20 are passed, and the air for burning the torch is sucked through the gap between the nozzle 12 and the chamber 3; at the same time, turn on the high-voltage voltage converter unit 9 and supply a high voltage (electric field) through the terminals 8 and electrodes 6, 7 to the flame 19, then measure the intensity and degree of purification of the toxic components of the exhaust gases 20 from the exhaust manifold 4 by sensors 17, which are processed in the microprocessor 18, the generated control actions are fed through control systems 10, 16, after which the intensity of the flame 19 and the parameters of the electric field are controlled by block 9 until the required level of purification of the exhaust gases 20 is reached. Then, the exhaust gases 20, which have undergone electric heat treatment, are fed through the inlet pipe 21 to the second cleaning chamber 22, where they are treated with a water-alkaline aerosol 28 created by forcing the water-alkaline emulsion 27 from the reservoir 26 by means of a pump 25 and nozzles 23 into the exhaust gas stream 20.

 The evaporated acidic fractions of the exhaust gases are condensed from the steam on the condenser 31, after which they are collected through a capillary filter 32 into a non-corrosive collection container 33 in the form of condensate 34 and are systematically removed through a tube with a valve 35, and completely purified exhaust gases 30 are discharged through the outlet pipe 29 into the atmosphere.

 The efficiency of purification of exhaust gases of any degree of contamination is achieved in the proposed method due to their complex electric firing and aerosol treatment, namely, the combination of a flame intensity-controlled with a strong electric field superimposed on it can significantly intensify the flame combustion process, almost double the flame temperature at the same gas flow rate, create a flow of charged particles from the electrodes 6, 7 towards the exhaust gases, which ultimately allows almost completely afterburning l hydrocarbons, soot, soot in the exhaust gases, rid them of smoke. At the same time, the electric field plays the role of an oxidizing catalyst for the conversion of carbon, sulfur, nitrogen oxides remaining from the fire treatment to dioxide, due to the generation of ions, electrons and ozonation of the incoming air. As you know, ozone is the most powerful oxidizing agent (80 times more effective than oxygen). The effect of deep purification of exhaust gases in the proposed electric fire method is also achieved through the operation of controlling the parameters of the flame and the electric field depending on the operating mode of the source of exhaust gases, for example, an internal combustion engine. Indeed, real objects - sources of toxic exhaust gases - often operate with a variable mode (forced fuel supply during the movement of loaded diesel vehicles uphill, take-off, rise of a gas turbine airliner, full loading of the waste incinerator). Therefore, the regulation of the degree of electric heat treatment, depending on the operating mode of the source of exhaust gases, will keep the degree of purification of the exhaust gases at the required level.

 It should be noted that chemical catalysts based on a honeycomb structure with a platinum coating are deprived of the ability to control the degree of purification of exhaust gases, in addition, they are generally inoperative for the purification of soot, smoke, soot, which are characteristic of many sources of exhaust gases (diesel transport, waste incineration plants). Therefore, the proposed method is more versatile in comparison with chemical methods of purification of toxic toxic gases. An additional degree of purification of exhaust gases that have undergone electric firing treatment is achieved due to their water-alkaline aerosol treatment with accumulation of condensate in a collection tank.

 Thanks to the introduction of this operation in the proposed method, the effect of deep purification of exhaust gases from less toxic but harmful to the environment in the form of "acid rain", sulfur oxides, carbon oxides, etc., is achieved, since aerosol injection of an aqueous alkaline emulsion at its minimum flow rate allows mainly to neutralize in the vapor formed from evaporation the acidic components of these oxides formed from the interaction with water vapor, respectively, the injected alkaline component. Therefore, the amount of harmful oxides is also significantly reduced in the exhaust gases.

 Improving the reliability of gas purification in this operation is achieved by collecting unreacted condensate in a collection tank, so the exhaust gases are almost completely cleaned of toxic and harmful components, cooled by aerosol and therefore environmentally friendly. The method has been tested experimentally. Test report attached.

Claims (2)

 1. The method of purification of exhaust gases by firing them with low-temperature plasma in the afterburner while simultaneously supplying an oxidizer to the combustion zone, characterized in that the contaminated exhaust gases are passed through a flame obtained by burning combustible gas, while applying an electric field of intensity to said flame E ≥ 1 kV / CM, along the flame, and the afterburner is made thermostatically and electrically insulated with a diameter and volume sufficient for deep afterburning of toxic components flue gases, regulate the parameters of the flame and the parameters of the mentioned electric field depending on the intensity and composition of the cleaned exhaust gases by measuring them before and after the electric firing treatment, comparing them with the reference values of the level of cleaning of toxic components and then changing the parameters of the flame and electric field, and then wet processing flue gas sprayed with an alkaline water emulsion, and the spray intensity is regulated depending on the intensity and composition of the flue gas, the last why condensed steam is condensed, and purified gases are released into the atmosphere.  2. The method according to claim 1, characterized in that the spray intensity of the water-alkaline emulsion is regulated by the electrostatic method with a change in the electric potential in the electrostatic pump.

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