The method of cleaning gas emissions and device for its implementation

 

(57) Abstract:

Can be used for chemical cleaning of exhaust gases during operation of technological areas. The gas is injected reagent, the effect of the diffuser electric discharge generated between the electrodes, and remove from the exhaust gas of the reaction products, and converted to natural gas with the surface of the at least one electrode serves electrolyte. The device comprises a reactor which contains the electrodes forming the inner surface of the channel for passing the purified gas and connected to the power source and mounted on the outlet gas from the reactor catcher reaction products, and at least one of the electrodes is supplied by a pipe connected to the compressor of the electrolyte, and a collector for receiving the spent solution, 2 S. and 4 C.p. f-crystals, 4 Il.

The present invention relates to the field of chemical purification of exhaust gases during operation of technological installations in various industries, in particular the burning of fossil fuels in the boilers of power plants, internal combustion engines.

Cleaning gas emissions and, in particular, the flue gases of industrial Ustinov gases nitrous oxide, including the injection of water, reducing the temperature of flue gases up to 80-120oC and mixing them with air, the introduction of the reagent in the form of an aqueous solution of carbonate and potassium nitrate when a molar ratio of 10:1 and concentrations of 0.15 to 0.19 and 0.015-0,019 and subsequent electron beam irradiation (see USSR author's certificate N 1662647 in class. B 01 D 53/34 from 03.11.1988 year).

The known method of purification of gas emissions have poor energy efficiency due to the small extent of the use of generated free radicals, requires the use of electron accelerators, because in addition to the need for radiation protection from cleaning high-voltage electron guns.

A device for cleaning gaseous emissions containing reactor, electron gun, the barrels of which are placed on opposite walls of the reactor, electronic accelerator, coupled to the power source and the device for introducing ammonia. At the exit gases from the reactor is installed aleurolites. (see USSR author's certificate N 1472118 in class. B 01 J 19/08 from 09.03.1987 year).

The disadvantages of the known device are the low energy efficiency and clonos Askania gas emissions through the zone streamer corona, formed by the electrode system "thread-cylinder" or "thread-plane", in which pulses of electrical energy high enough voltage to ensure, oxides of sulfur and nitrogen in acid fog (see U.S. patent N 4695358 in class. B 01 D 53/34 publ. 22.03.1987 year).

The implementation of this method in a large reactor volume is large technical difficulties, as the discharge develops from the electrodes in the form of separate conductive yarn, occupying only a small portion of the interelectrode space.

A device for cleaning gas emissions using pulsed streamer corona, comprising a cylindrical reactor with inlet and outlet nozzles for inlet gas to be purified and the purified gas release. Along the axis of the reactor is fixed to the insulator filamentary electrode connected to a pulsed high-voltage source (see U.S. patent N 4695358 in class. B 01 D 53/34, publ. 22.09.1987 year).

The disadvantages of the known devices are considerable technical difficulties of sustaining the existence of the discharge in large reactor volume, erosion of the electrodes.

The closest in technical essence to the problem at hand is the method of cleaning gas Woo two electrodes, the surface of one of which (cathode) evenly dotted with thin metal pins, each of which is loaded on individual ballast resistor (see Akishev Y. S., Levkin centuries, Napartovich A. P., N. Trushkin.And.- The use of glow discharge in the gas stream for the destruction of small impurities. - Materials of the seminar "Application of electron beam and pulsed discharges for flue gas cleaning".- M:IVTAN, 1991, S. 37-41).

In the known method the area intensively generating chemically active particles, is the entire volume of the discharge in contrast to the method using streamer corona, however, this method is not without drawbacks: the erosion of the electrodes, required pre-cooling the purified gas and forced air cooling of the electrodes, to create a diffuse electrical discharge is necessary to apply a voltage of one polarity.

A device for cleaning gas emissions, including the reactor, which is placed flat electrodes, one of which is equipped with a variety of needles, directed perpendicular to the second planar electrode. The electrodes form the inner surface of the channel for passing the purified gas. Electrodes connected with a source of the pic is to provide the necessary energy input, and, on the other hand, to avoid the arc stage of discharge. At the exit of the reactor is a filter for trapping particulate matter (see PCT application WO N 88/08325 in class. B 01 D 53/34, publ. 03.11.1988 year).

The known device has a complex structure that requires forced cooling of needles, in the device there is erosion of the electrodes, there is no possibility of applying the AC voltage.

The task was to create such a method of cleaning gas emissions and device for its implementation, which would increase the energy efficiency of the cleaning process without additional input of energy due to the increase of the contribution of the cyclic reaction with the regeneration of free radicals, simplify instrumentation and applied AC voltage.

The problem is solved in that in the method of cleaning gas emissions, including the introduction of a reagent gas, the impact of the diffusion of electric discharge generated between the electrodes, and the removal of exhaust gas products of the reaction, converted to gas, the surface of at least one electrode serves electrolyte, which can be used plain water. Rea is to be entered directly into the electrolyte, applied to the surface of the electrode. The electrolyte can also apply for facing to each other surfaces of the two electrodes, which apply in this case, the alternating voltage.

The problem is solved also by the fact that the device for purification of gas emissions, including the reactor, which contains the electrodes forming the inner surface of the channel for passing the purified gas and connected to the power source and mounted at the exit gases from the reactor catcher reaction products, at least one of the electrodes is supplied by a pipe connected to the compressor of the electrolyte, and a collector for receiving the spent electrolyte. Pipe for supplying electrolyte and a collector for receiving the spent electrolyte can be provided with two opposite electrode. One of the electrodes can be made porous and directly connected to the nozzle for supplying the electrolyte.

As a result of supplying electrolyte to the surface of one of the electrodes facing the gas between the liquid surface and the second electrode occurs volumetric diffuse discharge in the gas flow intensively introduced water vapor and droplets of electrolyte evaporation and rasiwasia solids and regeneration of free radicals in the droplet phase and, accordingly increases the energy efficiency of cleaning. There is an opportunity to use located on the surface of the electrode electrolyte for cooling the purified gas, which simplifies the cleaning process. When burning volumetric diffuse discharge in the case of applying the electrolyte to the electrode and the introduction of the reagent (reducing catalyst additives and so on, depending on the composition of impurities in the purified gas) the opportunity to provide metered introducing them into the stream of gas to be purified, which opens up new channels coupling reaction impurities and regeneration radicals and increase energy efficiency of the process. When the flow of electrolyte is converted to each other surfaces of the two electrodes becomes possible to use an alternating voltage, which simplifies the implementation of the method. Supply at least one of the electrodes of the device for cleaning gas emission pipe, coupled with the supercharger of the electrolyte, and a collector for receiving the spent electrolyte provides reliable coating layer of electrolyte the metal surface and thus stable combustion volumetric diffuse discharge, the constancy of the composition of the electrolyte due to recharge is not metal electrode, as in method-prototype; however, there is a simultaneous cooling of the electrode, eliminated the appearance of the constricted discharge. In addition, evaporation and splashing of the electrolyte can be used for cooling the purified gas. A supply pipe for supplying electrolyte and a collector for receiving the spent solution two opposite electrodes allows you to work on AC voltage, eliminating the need to use a straightening device. One of the porous electrodes and connecting it directly to the nozzle for supplying the electrolyte allows metered feeding the electrolyte through the pores on the surface of the electrode, while ensuring the cooling of the whole of its volume.

In the technique known the use of liquid electrodes for etching metals (see Gaisin F. M., Son of E. U.-Electrophysical processes in discharges with liquid and solid electrodes.- Yekaterinburg: Publishing house of Uralsk. University, 1989, 432 C. ). In the present method of purification of gas emissions, on the contrary, there is no etching (erosion) of the metal, and the supply of electrolyte to the electrode cools the purified gas, the cooling of the electrode, the changing nature of proceeding in RA the liquid electrodes for gas purification.

Device for cleaning gas emissions shown in the drawing, where Fig.1 schematically shows a General view of the device in section; Fig.2 is one possible design of electrode site when water on the surface of the two electrodes of Fig.3 - design of electrode site for the creation of a ring of diffuse discharge; Fig.4 - design of electrode site with a porous electrode.

Device for cleaning gas emissions includes a reactor 1 which contains the electrodes 2 and 3, forming the inner surface of the channel for the passage of gas to be purified, to supply which serves as the nozzle 4. The electrode 3 is supplied by a pipe 5 connected to the supercharger electrolyte 6, connected in turn by a pipe 7 with a capacity of 8 for electrolyte. Opposite to the inlet 5 side electrode 3 is a collection of 9 for receiving the spent electrolyte. When the supply of the electrolyte on both electrodes 2 and 3 (see Fig. 2) the pipe 5 and the collector 9 supply and the electrode 2. The electrode 3 on three sides (except the side adjacent to the collector 9 is provided with a flange 10, which forms thus the walls of the trays to hold the layer 11 of the electrolyte on the surface of the electrode 3. The collector 9 is connected by a pipe 12 both electrodes 2 and 3 (see Fig.2) they can be connected to the source 13 of alternating voltage. The electrode 3 when using unipolar voltage is typically grounded. The reactor 1 is supplied with the output nozzles 15 with filters 16 to capture the products of the reaction. In the pipe 15 can accommodate sensor gas composition analyzer 17. The electrode 3 may be provided with pores 18 for supplying electrolyte to the surface (see Fig. 4).

Device for purification of gas emissions is as follows. The electrolyte of the desired composition from the tank 8 through the pipe 7 by means of a blower 6 through the pipe 5 serves on the surface of the electrode 3. In the manufacture of the porous electrode 3, the electrolyte through the pores 18 is supplied to its surface. The excess of electrolyte through the collector 9 and the pipe 12 is returned to the tank 8. When applying to the electrode 2 high voltage from the power source 13 between the surface electrode 2 and the surface of the electrolyte 11 is lit volumetric diffuse electrical discharge forming chemically active free radicals. Cleaned from impurities gas through pipe 4 serves in a volumetric region of a diffuse electrical discharge between the electrodes 2 and 3. In the reaction of harmful impurity gas with Svobodnaya electrolyte from the electrode 3 to the initiation of cyclic reactions absorption of oxides and regeneration of free radicals in the droplet phase is cleaned gas from impurities with their transfer to the solid phase. At the same time and cooling the purified gas. Through volumetric diffuse discharge gas through the pipe 15 enters the filters 16, where the gas is separated solid particles, after which the cleaned gas released from the reactor 1.

The inventive method for treatment of gas emissions was tested on the model of the device. The distance between the electrodes was 1 cm, the electrode was applied potential difference of 2-4 kV depending on the qualitative and quantitative composition of the electrolyte. The speed of the purified gas was in the electrode gap of the order of 10 m/s, the current in the diffuse Pat tern of discharge reached 1 A. To the electrodes in the electrolyte was fed normal water. The experiments fully confirmed the advantages of the proposed cleaning method and device for its implementation before the method and device prototypes.

1. The method of cleaning gas emissions, including the introduction of a reagent gas, the impact of a diffuse electrical discharge generated between the electrodes, and the removal of exhaust gas products of the reaction, characterized in that converted to natural gas with the surface of the at least one electrode serves electrolyte.

2. The method according to p. 1, ex is .1, characterized in that the electrolyte serves on facing to each other surfaces of the two electrodes to which is applied an alternating voltage.

4. Device for cleaning gas emissions, including the reactor, which contains the electrodes forming the inner surface of the channel for passing the purified gas and connected to the power source and mounted on the outlet gas from the reactor catcher reaction products, wherein at least one of the electrodes is supplied by a pipe connected to the compressor of the electrolyte, and a collector for receiving the spent solution.

5. The device according to p. 4, characterized in that the nozzle for supplying electrolyte and a collector for receiving the spent solution is equipped with two opposite electrode.

6. The device according to p. 4, characterized in that at least one of the electrodes is made porous and directly connected to the nozzle for supplying the electrolyte.

 

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