Parallel scrubber with full bed impregnation capability

Abstract

The present design, entitled "Parallel Scrubber with Full Bed Impregnation Capability", is in the category of Electrical Control of Exhaust Gas Purification Equipment (F01N 9 / 00). Immersed scrubbers (pack scrubbers) are an important group of scrubbers in air pollution control equipment in which pollutant removal by a solvent usually occurs by increasing the contact surface and by using highly porous substrates. In fact, the surface of the substrates is wetted by a solvent that is sprayed or sprinkled on them, and the gaseous pollutants will have enough time to be absorbed and removed as they pass through the created surfaces. One of the problems with these systems is the lack of uniform distribution of the liquid over all the provided surfaces and the loss of the liquid during distribution and spraying (through evaporation). Therefore, an attempt has been made to eliminate the fluid distribution system by designing a parallel system of filled and emptied impregnated scrubber, in order to facilitate operation and reduce the complexity of the system, and to provide the largest contact surface and the lowest fluid consumption. Also, for the first time in this system, an attempt will be made to apply partial pressure so that the gas has maximum contact with the bed surface.

Description

Description of the invention Title of the invention (as stated in the declaration) Parallel scrubber with full bed impregnation capability Technical background of the relevant invention Section F: Mechanical engineering, lighting, heating and weapons and explosives; F01: Engineering in general; F01N: Gas exhaust equipment; F01N 9 / 00: Electrical control of exhaust gas purification equipment Technical problem and stating the objectives of the invention Scrubbers are considered important equipment for air pollution control in industries, and due to their importance and wide application in controlling particles and gases, various types of them have been designed and manufactured so far. During the process of absorbing pollutants in the scrubber, the pollutant-carrying gas comes into contact with a liquid solvent through spraying or injection, and the mass transfer of the pollutant from the gaseous medium to the liquid medium occurs through the physicochemical absorption of the pollutant in the solvent. Pack scrubbers or impregnated scrubbers are a group of these systems that increase the contact surface of the distributed gas and solvent by using special porous substrates (packs), leading to increased system efficiency. Problems associated with these systems include the lack of uniform distribution of liquid across all supplied surfaces and the loss of fluid during distribution and spraying (through evaporation). In the present design, the goal is to eliminate the fluid distribution system by designing a parallel system of filling and emptying pack scrubbers, which, in addition to ease of operation and reducing the complexity of the system, will result in providing the largest contact surface and the lowest fluid consumption.Also, for the first time in this system, an attempt will be made to apply a small amount of pressure so that the gas has maximum contact with the bed surface. A description of the state of the prior art and the history of developments related to the claimed invention. Traditionally, the term "scrubber" refers to pollution control devices that use a liquid to wash unwanted pollutants from a gas stream. This device is one of the main gas control devices used to clean air contaminated with a wide range of gases and dust particles. This unit operates by contacting gases or suspended particles with a special solvent (suitable for the target pollutant). Pack scrubbers are a group of such systems that use various types of substrates to enhance the transfer of pollutants from the gas to an absorbent liquid. The packs used in this type of scrubber can provide a large surface area for solvent contact with the gas and subsequently have a significant effect on the absorption efficiency. Therefore, by properly selecting the type and amount of substrate (pack), optimal conditions for mass transfer can be created. In the designs and studies that have been carried out so far on packed scrubbers, parameters such as residence time, column height, pack type and structure, nozzle and spray structure, and solvent type have been considered.Increasing the residence time or increasing the contact surface by using spray nozzles or special packs improves the efficiency of pollutant removal. Also, by increasing the height of the device, the contact efficiency can be increased. This system is made of a retaining network on which the substrate (pack) is placed. The solvent is distributed onto the substrate through a nozzle network placed on the substrate. The substrate causes the gas to follow a complex path opposite to the direction of the liquid and the contaminants in it dissolve in the liquid. More than a hundred types of substrates can be used in these systems. These substrates are made of various materials such as plastic, metals or ceramics and the structure of these substrates is such that they can provide more surface area to increase the contact of the contaminated gas or fluid. The choice of solvent type is also considered an essential parameter in the design of the scrubber. Today, various compounds such as water, HCl, NaOH, NaClO, H2O2, Na2S2O3, and Na2SO3 are used to wash and remove pollutant gases passing through scrubbers.In many systems, water is used as a detergent due to its ease of handling and low cost. However, the main point that is important in choosing a detergent is the type of gas and its polarity. In fact, the desired pollutant should be easily dissolved in the detergent for the system to show the highest efficiency in removing the pollutant. The characteristics of a good detergent include high solubility, high selectivity, high resistance, low volatility and regeneration ability. Providing a solution to an existing technical problem along with an accurate, sufficient, and integrated description of the invention As can be seen in Figure 1, each designed scrubber pack unit, unlike conventional units, does not have a fluid distribution system at the top, so that the solvent (1) will enter and exit only from the bottom of the tank. The bed (pack) (5) will be placed on a mesh support plate (4) at a certain distance from the contaminated gas distribution plate (3). The design and location of the contaminated gas distribution plate (3) inside the tank (7) are shown in Figures 1 and 2. The location of the two scrubber units A and B as a parallel system is shown in Figure 3. While scrubber B is performing the gaseous pollutant removal operation, the fluid enters scrubber A through the pipe installed in the bottom (1) by means of a pump (8) and, by filling it, will come into complete contact with the bed (pack) (5). In such a situation, unlike the solvent holding and draining valve of scrubber A (9), the solvent holding and draining valve in scrubber B (10) will be closed to prevent fluid from entering scrubber B.Also, to prevent the contaminated inlet gas (2) from entering scrubber A and transferring it to scrubber B, the contaminated gas control valve for scrubber A (11) will be closed and the contaminated gas control valve for scrubber B (12) will be open. In order to ensure complete contact of the contaminated gas with the bed and increase the dissolution rate, the scrubber B clean gas control valve (14) will be temporarily opened and closed to apply a partial pressure. This is while the scrubber A clean gas control valve (13) will be open during the bed washing and filling operations. Also, by reducing the cross-section of the outlet gas pipe relative to the inside or half-opening of valves 13 and 14, it will be possible to slightly increase the pressure in the scrubber. Finally, after the pollutant in the outlet pipe (6) reaches the breaking point, the operating state of the valves will be reversed and the clean solvent will be transferred to tank B for washing the bed and filling it. It is worth noting that the system has the ability to use solenoid valves and can be controlled and operated completely automatically. An overview of the process can be seen in the form of a block diagram in Figure 4. Explanation of shapes, maps and diagrams Map No. 1: Components of each scrubber unit 1) Solvent inlet and outlet pipe 2) Contaminated gas inlet pipe 3) Contaminated gas distribution plate 4) Bed retaining plate 5) Bed (pack) 6) Clean gas outlet pipe 7) Tank Map No. 2: View of the gas distribution system 2) Contaminated gas inlet pipe 3) Contaminated gas distribution plate 7) Tank Map No. 3: Parallel system location with display of valves and pumps 8) Solvent injection and discharge pump 9) Solvent storage and discharge valve in scrubber A 10) Solvent storage and discharge valve in scrubber B 11) Scrubber A contaminated gas control valve 12) Scrubber B contaminated gas control valve 13) Scrubber A clean gas control valve 14) Scrubber B clean gas control valve Map #4: Process Block Diagram A clear and precise statement of the advantages of the claimed invention over prior inventions. 1.Reducing energy consumption 2. Increasing the contact surface of the pollutant with the absorbent material 3. Reducing unit dimensions 4. Reducing fluid loss through evaporation 5. Reducing management costs 6. Reducing halal consumption 7. Using a variety of cross-sections (circular, square, rectangular, etc.) for design and construction Description of at least one implementation method for implementing the invention In the present design, at least two parallel scrubbers with the structure described above are required. While one scrubber is being washed or filled, the other scrubber will be removing the target contaminants under partial pressure while its entire bed surface is impregnated with solvent. Explicit mention of the industrial application of the invention Depending on the type of air pollutant produced, various industries can use a system designed to control emissions. Brief description of the invention The present design, entitled "Parallel Scrubber with Full Bed Wetting Capability", was placed in the electrical control category of exhaust gas treatment equipment (F01N 9 / 00). Packed scrubbers are an important group of scrubbers in air pollution control equipment in which pollutant removal by a solvent usually occurs by increasing the contact surface and by using highly porous substrates. In fact, the surface of the substrates is wetted by a solvent that is sprayed or sprinkled on them, and gaseous pollutants will have sufficient opportunity to be absorbed and removed while passing through the created surfaces. One of the problems of these systems is the lack of uniform distribution of liquid on all supplied surfaces and the loss of fluid during distribution and spraying (through evaporation). Therefore, an attempt has been made to eliminate the fluid distribution system by designing a parallel system of filled and emptied packed scrubbers, in order to provide the greatest possible contact surface and the lowest possible fluid consumption, in addition to ease of operation and reducing the complexity of the system.Also, for the first time in this system, an attempt will be made to apply a small amount of pressure so that the gas has maximum contact with the bed surface.

Claims

Claim What is claimed: Claim 1) The design of a fill-and-empty scrubber pack system is made of at least two parallel scrubber packs without a solvent distribution system, and the washing and impregnation process is carried out by filling and emptying each unit. Claim 2) According to claim 1, the system operates such that at least one scrubber unit is filling and washing the bed, and the other unit(s) are empty of fluid and are removing contaminants through wetted surfaces. Claim 3) According to claim 1, the solvent distribution and spray system is removed from the system, resulting in reduced evaporation and fluid loss. Claim 4) According to claims 1 to 3, by filling the tank, all surfaces in the bed will be impregnated with fluid and the efficiency of the system will increase. Claim 5) According to claim 1, by applying partial pressure, the contaminated gas will be present on all surfaces and the absorption efficiency will increase.

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