BG66749B1 - Method and device for electrochemical plasma flue gas purification - Google Patents

Abstract

Flue gas purification method and apparatus, in which the flue gases move horizontally in a reactor representing a horizontally disposed chamber, the upper surface of which is a cathode needle , and a thick water stream circulating along the lower one, representing an anode moving in opposite direction to the movement of the gases, during which time, due to the high voltage supplied to the cathode, electrons are emitted from the needles, which ionize the molecules of the gas by moving perpendicularly to the gas and water stream and the water vapour in them, wherein recovery and oxidation processes take place, and thus formed oxide radicals and recovered elements fall into the flowing water anode, which takes them outside the reactor.

Description

(54) METHOD AND DEVICE FOR ELECTROCHEMICAL PLASMA PULSE CLEANING OF Flue Gases

Field of application

The invention relates to the purification of flue gases from various boiler installations in order to achieve an acceptable ecological environment.

BACKGROUND OF THE INVENTION

A technology for complex purification of gases is known, described in Eurasian patent 005264, issued on 30.12.2004. This technology is intended for regenerative purification of flue gases from harmful oxides and is based on the principles of plasma gas electrochemistry, namely the fact that the gas streams pass through a zone with directed exiting electrons from the needle cathode and directed to the anode. Electrons with sufficient energy excite and break down the molecules of harmful gas components and the water vapor contained in the gas stream of ions and radicals, as a result of which the sulfur, carbon and nitrogen included in the gas oxides are restored, as the formed molecular nitrogen leaves the reactor with the purified exhaust gases, and sulfur and carbon are reduced to neutral elements, fall on the anode and are removed from the reactor with an aqueous flowing layer. The reactor in which these processes take place has a reaction zone formed between two intersecting cones vertically facing the bases upwards. Inside one of the larger cones is inserted the smaller one and represents a needle cathode, and the outer one performs the function of an anode on the inner surface on which the water layer flows. The treated gases pass through a reaction zone formed between the height-shifted cones, where they are treated with the electron flow.

The invention EA 0052626 / B1 of 2004.01.26 is known, differing from the above only in that it clarifies the action of the atomic hydrogen required for the reducing chemical process.

Invention No. 200800310 (A1) of 2007.12.29 describes a method for cleaning flue gases from their harmful components, which invention does not differ substantially from the previous two inventions. The only difference is in the device for implementing the method, which device is shaped like a cylinder located vertically.

An invention is known as invention B 110813 (A), in which the purification of the flue gases from the harmful component gases is based on pure chemical processes without the participation of electron irradiation.

The description of the invention EP 0697235 A1 of 16.08.1995 sets out the possibilities for feeding only ammonia applicable only to the realization of oxidative processes, in which case an electron flow is directed to the flue gas only in a part of the reaction chamber. The electron flow is probably from an electron gun, because there is no mention of the presence of a cathode and anode needed to form an electric field. The technology is realized in a dry volume, due to which dust collectors are provided for collecting the formed compounds.

Technical essence of the invention

The present invention relates to a method for electrochemically plasma purification of flue gases from oxide impurity gases, the flue gases moving horizontally in the cathode-anode reaction zone in a direction opposite to the movement of a horizontal water stream representing the water anode. When a high voltage is applied from the upper cathode surface of the reaction zone, electrons are emitted, which, moving perpendicular to the gas stream and the water anode stream, ionize the molecules of the gases and the water vapor in them. The products of the ongoing electrochemical reactions fall into the flowing aqueous layer, which carries them out of the reaction zone.

Oxidative purification of the flue gases is carried out through the electrochemical supply of the cathode, and conditions for oxidation of sulfur dioxide, carbon dioxide and nitrogen oxides are created in the aqueous layer. In the water they form an acid mixture in which ammonia or sodium hydroxide is fed after leaving the reaction zone. This gives a complex product which contains sodium nitrate, nitrogen nitrate, ammonium sulphate and ammonium carbonate.

Ammonia and sodium hydroxide solution can also be fed directly into the reaction zone. Through

Descriptions of issued patents for inventions № 11.2 / 30.11.2018 subsequent crystallization outside the reactor gives a solid product. The resulting complex product inside or outside the reaction zone, containing sodium nitrate, nitrogen nitrate, ammonium sulfate and ammonium carbonate, can be used in crop production as a fertilizer.

The transformations of the molecules of the harmful gases and the water vapor contained in the flue gases into excited molecules, electrified radicals and atoms, ions and reduced elements take place between a needle cathode located horizontally and a horizontal water stream / anode /, between which the flue gases move. in the direction opposite to the movement of the water flow. The horizontal or almost horizontal water flow allows it to be of any thickness and to move smoothly, which eliminates any possibility of dropping drops and water splashes into the reaction space, leading to unwanted spark formations and short circuits. In addition, the greater flow thickness creates a larger volume capacity for the products of the ongoing electrochemical reactions, which in turn leads to the possibility of passing larger volumes, even highly concentrated with harmful impurities, flue gases.

The flue gas cleaning device according to the method is a horizontal reaction chamber. The upper side of the chamber is a needle cathode, and above the lower flows a stream of water, which serves as an anode. The thickness of the water flow is changed with the help of a sliding regulator. The water enters the reaction chamber through the ascending tube. The outlet for the cleaned gases is located on the same side of the chamber. A gas distribution grid with openings is formed on the opposite side of the reaction chamber. The flue gases are fed through an inlet pipe into a hollow inclined prism mounted in front of the gas distribution grille, the hollow inclined prism on the other side being connected to a slide level regulator with a working plate for regulating the water flow.

Such devices can easily be manufactured with different gas volume capacities, simply made with different lengths and widths to obtain the desired volume of reaction zone. In the case of gases accumulating reaction products on the blades of the cathode needles, these accumulations can be easily removed by making perforations at the bottom of the high voltage zone through which streams of compressed air are fed parallel to the needles, sliding the accumulations on the needles. Depending on the circuit for power supply of the cathode / constant, pulse or mixed voltage / oxidative cleaning of the flue gases is also possible.

The present invention eliminates the following technological difficulties:

- the difficulties in making the cones and mounting the numerous needles on a conical or cylindrical surface;

- the formation of a reaction zone between two vertically inverted cones, which forces the water layer flowing on the solid surface of the cone to be kept relatively thin in order to avoid the formation of waves, which can form drops and splashes, causing short circuits. ;

- the formation of a reaction zone between the two cones also leads to a gradual thickening of the water layer from top to bottom, which is also accompanied by possible water wavy formations with the consequences of short electrical connections;

- the thin layer of water requires to work with relatively reduced productivity due to the rapid saturation with the reaction products.

An exemplary embodiment of the proposed device is shown in the attached figure with the following positions:

- horizontal reaction chamber

- water inlet

- needle cathode

- slide level regulator

- flue gas inlet

- hollow inclined prism

- gas distribution grille

- water level

Descriptions of issued patents for inventions № 11.2 / 30.11.2018

- purified flue gas outlet.

The inlet flue gas flow through the supply chamber is fed to a perforated distribution plate, which evenly distributes it along the cross section of the reaction zone formed between the surface of the water stream and the needle cathode located at the bottom of the high voltage zone. The counter-flow of the gas stream and the water have the advantage that initially the gases move over the water already saturated with products of the reaction processes, and finally over the water with a small concentration of such products, which helps to quickly remove these products from the water. they are dispersed in its volume. As shown, the thickness of the water flow can be changed depending on the concentration of harmful gaseous impurities, using a sliding regulator, the working plate of which can be changed in height.

Claims (5)

Patent claims Method for electrochemical plasma flue gas cleaning, characterized in that the flue gas stream moves horizontally in the cathode-anode reaction zone in a direction opposite to the movement of the horizontal water stream, representing the aqueous anode anode, during feeding at high voltage, emitting electrons from the upper cathode surface that move perpendicular to the flue gas flow and the water anode flow, which electrons cause electrochemical reactions involving excitation, breakdown and ionization of the flue gas molecules and water vapor in them, as the products of the ongoing electrochemical reactions are captured by the water flow, which takes them out of the cathode-anode reaction zone. Method according to Claim 1, characterized in that oxidative purification of the flue gases takes place by the electrical supply of the cathode, creating conditions for oxidation of the sulfur dioxide, carbon dioxide and nitrogen present in the flue gas stream in the cathode-anode reaction zone. oxides which form an acid mixture in the aqueous anode stream to which ammonia or sodium hydroxide is fed after leaving the cathode-anode reaction zone, resulting in a complex product containing sodium nitrate, ammonium nitrate, ammonium sulphate and ammonium carbonate. Process according to Claim 1, characterized in that the ammonia or sodium hydroxide is fed directly into the cathode-anode reaction zone, whereby a complex product is obtained in solution, from which, after removal from the reaction zone, solid products are obtained by crystallization. . Flue gas cleaning device according to the method of any one of the preceding claims, characterized in that it is a horizontal reaction chamber (1) in the shape of a parallelepiped, comprising a high-voltage zone with a bottom, the upper side of which is a needle cathode ( 3), as on one base of the reaction chamber (1) is mounted an ascending tube (2), above it to the needle cathode is located an outlet (9) for the purified gases, where on the opposite side of the horizontal reaction chamber (1) is mounted grille (7), in front of which a hollow inclined prism (6) is mounted, with an inlet pipe (5) for flue gases, the inclined prism (6) being attached to a sliding level regulator (4) for regulating the level of the horizontal water flow. Device according to claim 4, characterized in that the bottom of the high voltage zone is perforated.