BG66691B1 - Electrochemical flue gas purification method and device - Google Patents

Abstract

The invention relates to a method for the plasma electrochemical purification of flue gases from harmful impurities by generating a wide-range acoustic emission and pulsed gas effects in the reaction zone, and the devices for implementing the method are designed to incorporate the following principal solutions: - an acoustic generator which, under electrical, pneumatic and hydraulic action, generates acoustic radiation; - a pneumatic pulsator generating discrete sequential pulsating impulses and pulsations with constant force, combined with oscillating or rotational motion; - a reaction chamber formed between an electrode needle and an electrode sheet, depending on the physicochemical characteristics of the gases, the needle electrode is negative and the sheet electrode is positive or vice versa.

Description

Field of technology

The invention relates to a method and a device for plasma electrochemical purification of flue gases and a device which is also used for oxidative electrochemical purification of gases with a suitable power supply.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 6,565,633 B1 describes an electronic method for neutralizing harmful sulfur and nitrogen oxides, in which ammonia is introduced into the reaction zone to transform these gases into ammonium compounds as a result of the oxidative action. The electrons are emitted by an electron gun and when they enter the reaction zone, electrodes with different electrical potentials located inside the chamber are directed into a stream bypassing the reaction zone. The disadvantage of this method is that it serves only for oxidative neutralization of harmful gases with the additional use of ammonia, which is expensive and dangerous, and the electronic rifle is a complex device to operate.

Patent BG 51440 A of 24.08.90 describes a method for electronic action on flue gases, the electrons being emitted by a corona discharge. The technology and the device are designed solely to ionize the solid ash particles present in the flue gases and therefore their use for the purpose of cleaning the harmful gases is impossible, as a result of which the molecules of these gases are neither excited nor separated. of ions or radicals in the reaction zone of the device.

A method and device for cleaning gases from odors / patent CN 201969474 from 14.09.2011 / as the gases pass through holes in mesh anodes and cathodes. A significant disadvantage is the accumulation of solid deposits on the wires of the networks, which requires complex cleaning to maintain the process and prevent accidents.

A technology for complex purification of gases from the main harmful components in a reactor is known (Eurasian patent 005264 from 2004.12.30). This technology is based on the principles of plasma gas electrochemistry, namely the fact that when passing a gas stream through a zone with directed electrons coming out of the needle cathode and directed to the anode, the electrons with sufficient energy excite and break the molecules of harmful gas components and containing in the flue gas water vapor of ions and radicals, as a result of which the ash particles are negatively charged and, like electrostatic precipitators, are captured at the anode, and the charged particles of sulfur and carbon are captured, which are reduced to neutral elements and are separated at the anode, on the surface of which flows an aqueous layer, which brings the trapped elements sulfur and carbon out of the reactor. Nitrogen is released from the nitrogen oxides as molecular nitrogen and leaves the reactor with the purified exhaust gases. Depending on the circuit and the source of the electrons, an option with oxidative flue gas cleaning is possible, with the newly formed oxides reacting with added substances, such as ammonia, to form ammonium nitrate and ammonium sulphate, which are used as fertilizers. However, oxidative purification of gases does not solve the problem of carbon monoxide capture, so the hopes for complex capture of gaseous harmful components are placed on the reduction purification.

The realization processes according to the technology of said patent are carried out in a device, the reaction zone of which is formed between the inner surface of an upside-down cone and the outer surface of an upside-down cone placed at a certain distance inside the first cone. The cone inserted inside is a needle electrode (cathode) with needles protruding on its surface, directed to the outer cone (anode), on the inner surface of which the water layer flows. When a sufficiently high voltage is applied to the cathode, electrons that have left the needle blades pass through the reaction zone, forming

Descriptions of issued patents for inventions № 07.2 / 31.07.2018 dark or smoldering discharge. From the collisions of electrons and molecules, the latter are excited and decompose into ions and radicals. Therefore, plasma is formed, as the reduced sulfur and carbon atoms, leaving the aqueous layer, leave the reaction zone.

Eurasian patent 200800310 A1 of 29.12.2007 describes a method for cleaning flue gases from their harmful components, which does not differ in essence from the method described in the previous patent. The only difference is in the device for implementing the method, which in this patent is given in a cylindrical shape. The technological disadvantages are the same as in the previous patent Ei 005264 B1, and the cylindrical shape makes it difficult to change the volume of the reaction zone, which limits the productivity of the gas flow.

Disadvantages of the restoration technology and the device for its implementation can be noted:

- Difficulties in making the cones and mounting the numerous needles on the surface of the electrode.

- The need to supply air to the area of the reaction zone where the needles are located to clean them of accumulated particles on the blades. This dilutes the flue gases and, therefore, reduces the capacity of the device or reduces the cleaning efficiency if it is necessary to increase the speed of the flue gases passing through the reaction zone.

- Loss of elemental sulfur and carbon is possible because the recovered elements are very small, ie. they are light and can be partially entrained by the outgoing gas flow.

- No alternative to complex gas cleaning with a dry electrode has been proposed in order to avoid the complicated processes for separation of the solid phase from the leaving water stream. These processes are thickening, filtration and drying.

The invention aims to reduce the damage from these disadvantages or eliminate them altogether.

Technical essence of the invention

To achieve the set goal, intensifying factors of the gas purification process are used, which facilitate the purification of the emitting electron needles from accumulated reaction products, creating conditions in the reaction zone for consolidation of the particles of newly obtained substances, which reduces their export. from the exhaust gases and facilitates their retention by the anode. There is an opportunity for design, construction, installation and maintenance of complex gas cleaning devices.

This is due to:

- Impulse supply of the gas flow in the reaction zone in order to create pulsations in the flow, which due to the differences in the impositions during the pulsations generate gas force effects, which "break off" the deposits on the electrode needles. In addition, a slight turbulence can be created in the gas flow, which improves the efficiency of gas cleaning. In the simplest case, the impulse action can be realized by installing impeller pulsators in the inlet gas pipeline.

- Bringing the needle electrode in low-intensity vibration, which alone or together with the pulsed gas action, realizes the cleaning of the electrode needles from deposits, which eliminates the need to supply air to the reaction zone to achieve this cleaning. For this purpose, a suitable electric, pneumatic or hydraulic vibrator is mounted to the electrode frame.

- Generation of wide frequency acoustic radiation in the reaction zone for formation of moving and standing acoustic waves. The wide frequency range assumes the presence of different sound frequency force effects, so that different in mass molecules, ions, radicals and elemental particles by appropriate frequency are brought into resonant state, which not only supports collision reactions, but accumulates the formed elemental particles in the nodes of standing waves, which helps to consolidate them into aggregates and subsequently to capture them at the anode. In the simplest case, for this purpose, an acoustic generator / whistle / of pneumatic type is installed at the inlet of the reaction zone, as a small part of the flue gas entering the reactor is passed through the whistle (s).

Descriptions of issued patents for inventions № 07.2 / 31.07.2018 for creating an acoustic field.

- Use of flat and curved in one plane electrode plates, which facilitates the construction and maintenance of the gas cleaning device in a complete or modular design.

Device for carrying out the invention

The invention is illustrated by the following exemplary embodiments suitable for performing wet or pneumatic electrochemical flue gas cleaning, wherein the accompanying figures represent:

Figure 1 - single-chamber water purifier;

figure 2 - pulsator in two versions;

figure 3 - reaction zone in two variants;

Figure 4 - modular water purifier;

figure 5 - variant of the gas cleaner according to fig. 4;

Figure 6 - two-chamber pneumatic gas cleaner;

Figure 7 - multi-chamber pneumatic gas cleaner.

The one-chamber water purifier is a prism 1 in which the flue gas is purified and performs the function of a reaction zone. Attached to the prism are an inlet tip 2 and an outlet tip 3 with an outlet 10. The tips are shaped like truncated pyramids. One side of the prism 1 is shaped like a needle electrode 4, and the other opposite side is a sheet electrode 7. Water is supplied to the sheet electrode in the form of an aqueous layer from a tube 6 located in the upper part of the electrode 7. The tube 6 is grounded, and the water flows through a dielectric insulated pad through outlet 11 in the form of an aqueous suspension.

The flue gas enters the inlet nozzle 2 through locator 8, in which pulsator 9 is located, for complete - / fig. 2a / or partially - / fig. 2c / interruption of the gas flow at high flow rates. Upon entering the reaction chamber, the gases are sounded by the acoustic generator 5.

Thus, the pulsation is a constant force component.

A vibrator 12 is provided to generate a low-intensity vibration, preferably a light shock. Vibration can also perform the function of an acoustic emitter.

To facilitate the construction, installation and maintenance of large gas cleaners, they can be made not only as modules fig. FIG. 4, FIG. 5, but also with sequentially mounted sections - fig. 7.

Claims (5)

Patent claims Method for plasma electrochemical purification of flue gases from harmful impurities, including fine particles, characterized in that it is carried out in the following stages: - in a provided cathode-anode reaction zone, wide-range acoustic radiation is generated; - a pulsed supply of flue gases in the cathode-anode reaction zone follows, in which under the influence of the acoustic radiation the fine particles are consolidated and upon reaching the anode the gas flow is diverted to the intended unloading zone, and the consolidated particles are captured by a secure flow at the anode in a perpendicular direction, water flow. Method for plasma electrochemical purification of flue gases from harmful impurities, including fine particles according to Claim 1, characterized in that turbulence is also generated during the pulse supply of the impure flue gases. Device for carrying out the method of claim 1, characterized in that an inlet nozzle (2) provided with an acoustic emitter (5) is connected to the reaction chamber, which is a prism-shaped body (1), at both opposite ends. an output limb (3), respectively, a locator (8) is mounted to the input nozzle (2), in which a pulsator (9) is placed, where one side of the reaction chamber is a needle electrode-cathode (4), and its opposite side is a sheet electrode-anode (7), in the upper part of which is attached a tube (6). Device according to claim 3, characterized in that the needle electrode-cathode (4) is placed between two sheet electrode-anodes (7) to which a vibrator (12) is attached. Device according to Claim 3 or 4, characterized in that in the reaction chamber, Descriptions of issued patents for inventions № 07.2 / 31.07.2018 representing a prism-shaped body (1), at least two sheet electrodes-anodes (7) are fixedly connected, between which the needle electrodes-cathodes are attached (4) , as in the upper part of the leaf electrodes-anodes (7) the vibrator (12) is provided.