Fly ash removal system for coal bed gas production

Abstract

The utility model discloses a fly ash removal system for coal bed gas production. The fly ash removal system comprises a wet dust collector, an air flotation water purifier, a rotary slag scraper, a plate-and-frame filter press, a magnetized water treater and a dosing device, the wet dust collector is connected with an air inlet pipe, the top of the wet dust collector is provided with a discharge pipe, the bottom of the wet dust collector is connected with the air flotation water purifier through a first pipeline, the first pipeline is provided with a pressure reducing valve, the rotary slag scraper is arranged above the air flotation water purifier, and the plate-and-frame filter press is connected with a slag collecting groove of the rotary slag scraper through a second pipeline. The lower part of the rotary slag scraper is connected with a wet dust collector through a third pipeline, a water circulating pump is connected to the third pipeline close to the rotary slag scraper, and a magnetized water processor is connected to the third pipeline close to the wet dust collector. The purification efficiency of the system is far higher than that of traditional washing equipment such as a traditional spray tower and a packed tower, and generally, the dust removal efficiency exceeds 99%.

Description

Technical Field

[0001] The utility model relates to the technical field of fly ash removal, in particular to a fly ash removal system for coal bed gas production. Background Art

[0002] In the process of coalbed methane development, the output of coal powder is inevitable. The problem of fly ash in coalbed methane in the gathering and transportation system has always existed. Due to the low density of coal and the small particle size of fly ash, which is usually less than 10 microns, and the hydrophobic and oleophilic surface characteristics of coal, conventional wet dust removal is difficult to achieve the ideal removal effect. Conventional mechanical dust removal such as gravity sedimentation and cyclone is ineffective. At present, mechanical filtration is usually used to complete the purification work. However, in the actual production process, it is found that mechanical filtration methods such as bag filters and filter elements have problems such as frequent replacement and easy damage.

[0003] It has been observed that the fly ash carried by coalbed methane has both toughness and rigidity. Toughness is manifested in that it can drill the tiny pores of the filter element in various postures, and toughness is manifested in that it is not easy to break at the microscopic level. The combination of these two characteristics makes traditional filtration-type dust removal less suitable. On the one hand, due to the limited dirt holding capacity of the filter, the filter element and filter bag need to be cleaned and replaced constantly. On the other hand, since the particle size of fly ash in coalbed methane is very small, for example, sampling and analysis of the compressed air entering a central processing plant of a coalbed methane field shows that the particle size of 0.1-0.5μm accounts for 63%, 0.5-1.0μm accounts for 33%, and 1-5μm accounts for 3.4%. It is difficult to select the material of the filter element or filter bag to deal with such fine fly ash. At the same time, the mud cake formed on the surface of the filter element or filter bag of ultra-fine particle size fly ash has a large pressure difference, and the filter element or filter bag is easy to be damaged. Utility Model Content

[0004] In view of the deficiencies of the prior art, the utility model provides a fly ash removal system for coalbed methane production, so as to achieve efficient removal of fly ash in coalbed methane during the coalbed methane production process.

[0005] In order to solve the above technical problems, the utility model provides the following technical solutions:

[0006] A fly ash removal system for coalbed methane production includes a wet dust collector, an air flotation water purifier, a rotary scraper, a plate and frame filter press, a magnetized water processor and a dosing device; the wet dust collector is connected to an air intake pipe, the air intake pipe is provided with an incoming air control valve, the top of the wet dust collector is provided with a discharge pipe, the discharge pipe is provided with a purified air control valve, the bottom of the wet dust collector is connected to the air flotation water purifier through a first pipeline, the first pipeline is provided with a pressure reducing valve, the rotary scraper is arranged above the air flotation water purifier, The plate and frame filter press is connected to the slag collecting tank of the rotary scraper through the second pipeline, and the suspended foam on the surface of the flotation water purifier is scraped into the plate and frame filter press through the rotary scraper. The lower part of the rotary scraper is connected to the wet dust collector through the third pipeline. A water circulation pump is connected to the third pipeline near the rotary scraper, and a magnetized water processor is connected to the third pipeline near the wet dust collector. The dosing device is arranged next to the flotation water purifier, and a surfactant is added to the flotation water purifier through the dosing device.

[0007] Preferably, the dosing device comprises a dosing barrel, a stirring mechanism is arranged in the dosing barrel, the dosing barrel is connected to the air flotation water purifier through a fourth pipeline, and a dosing pump is connected to the fourth pipeline.

[0008] Preferably, a safety valve and a pressure gauge are connected to the upper portion of the wet dust collector.

[0009] Preferably, the first pipeline is also connected to a liquid level regulating valve, and the liquid level regulating valve is located between the wet dust collector and the pressure reducing valve.

[0010] Preferably, a filter pressure pump is connected to the second pipeline.

[0011] Compared with the prior art, the utility model has the following beneficial effects:

[0012] 1. High purification efficiency. The purification efficiency of this system is much higher than that of traditional washing equipment such as spray towers and packing towers. Generally speaking, the dust removal efficiency exceeds 99%.

[0013] 2. Stable and reliable operation, not easy to clog. Since the washing process uses activated water technology, the circulating liquid can allow a higher solid content without clogging. The higher solid content of the circulating liquid can reduce the amount of sewage discharged, thereby reducing the load and scale of sewage treatment. Generally, traditional equipment can hardly withstand a circulating liquid solid content of more than 3%, while the system can reach a circulating liquid solid content of more than 20% without clogging. Therefore, the system has high reliability, is not easy to damage, is easy to operate and maintain, and has a long operating cycle.

[0014] 3. Flexible configuration and wide application range. For example, it has good cooling effect, can be used to treat high-temperature gas, is not easy to clog, has almost no limit on the fly ash content in the gas, and the allowable dust content in the circulating fluid is also extremely high. It can greatly reduce the amount of waste liquid pumped out, making waste liquid treatment easier. It has a small shape, no moving parts, and the working process is not affected by pressure fluctuations.

[0015] 4. It has a wide range of gas volume adaptability and can adapt to 50%-100% gas volume changes without reducing the washing efficiency. It avoids the narrow operating range of traditional cyclone dust removal due to the need for a higher linear speed.

[0016] 5. Low investment. The system has a simple structure, can be skid-mounted, is easy to configure and flexible, and saves investment and land. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the utility model;

[0018] In the figure: 1-wet dust collector, 2-air flotation water purifier, 3-rotary scraper, 4-plate and frame filter press, 5-magnetized water processor, 6-dosing device, 601-dosing barrel, 602-dosing pump, 7-discharge pipe, 8-first pipeline, 9-pressure reducing valve, 10-second pipeline, 11-third pipeline, 12-water circulation pump, 13-magnetized water processor, 14-fourth pipeline, 15-safety valve, 16-pressure gauge, 17-liquid level regulating valve, 18-filter pressure pump, 19-intake pipe, 20-inlet air control valve, 21-purified air control valve DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0020] See also Figure 1 A fly ash removal system for coalbed methane production includes a wet dust collector 1, an air flotation water purifier 2, a rotary scraper 3, a plate and frame filter press 4, a magnetized water processor 5 and a dosing device 6.

[0021] The wet dust collector 1 is connected with an air intake pipe 19, and the gathering and transportation system is connected with the air intake pipe 19 so as to transport coalbed methane to the wet dust collector 1. The air intake pipe 19 is provided with an incoming gas control valve 20. The top of the wet dust collector 1 is provided with a discharge pipe 7, and the discharge pipe 7 is provided with a purified gas control valve 21. The discharge pipe 7 is used to discharge the purified coalbed methane. The upper part of the wet dust collector 1 is connected with a safety valve 15 and a pressure gauge 16 to ensure production safety.

[0022] The bottom of the wet dust collector 1 is connected to the flotation water purifier 2 through a first pipe 8, and a liquid level regulating valve 17 and a pressure reducing valve 9 are connected to the first pipe 8. The liquid level regulating valve 17 is located between the wet dust collector 1 and the pressure reducing valve 9. The accumulated water at the bottom of the wet dust collector 1 is controlled to have a stable liquid level by the liquid level regulating valve 17, and then passes through the pressure reducing valve 9, and the dissolved gas in the water will generate tiny bubbles.

[0023] The rotary scraper 3 is arranged above the air flotation water purifier 2, and the plate-frame filter press 4 is connected to the upper part of the rotary scraper 3 through the second pipe 10. The suspended foam on the surface of the air flotation water purifier 2 is scraped into the plate-frame filter press 4 through the rotary scraper 3, and the second pipe 10 is connected to the filter pressure pump 18. The dissolved gas in the water will generate tiny bubbles and enter the air flotation water purifier 2. The small bubbles carry the fly ash to the water surface, are scraped to the slag collecting tank by the rotary scraper 3, and then are pressurized into the plate-frame filter press 4 by the filter pressure pump 18, and finally the fly ash is removed.

[0024] The lower part of the rotary scraper 3 is connected to the wet dust collector 1 through the third pipe 11. A water circulation pump 12 is connected to the third pipe 11 near the rotary scraper 3. A magnetized water processor 13 is connected to the third pipe 11 near the wet dust collector 1. The purified water is pressurized by the water circulation pump 12, and then passes through the magnetized water processor 13 (the magnetized water is called activated water) to enter the wet dust collector for recycling.

[0025] The dosing device 6 is arranged beside the air flotation water purifier 2, and a surfactant is added to the air flotation water purifier 2 through the dosing device 6. Specifically, the dosing device 6 comprises a dosing barrel 601, in which a stirring mechanism is arranged, and the dosing barrel 601 is connected to the air flotation water purifier 2 through a fourth pipe 14, and a dosing pump 602 is connected to the fourth pipe 14.

[0026] The wet dust removal is a device that allows the coalbed gas containing fly ash to be in close contact with activated water, and uses the inertial collision between droplets and fly ash particles and other effects to capture fly ash, which can effectively remove liquid or solid dust of 0.1 to 20 μm. The wet dust collector 1 described in the present application can be selected from any one of the wet scrubbers such as spray tower scrubber, cyclone scrubber, drum scrubber, impact scrubber, Venturi scrubber, packing scrubber, etc.

[0027] Air flotation water purification: It uses highly dispersed tiny bubbles as carriers to adhere to pollutants in wastewater, making their buoyancy greater than gravity and floating resistance, so that pollutants float to the water surface, forming foam, and then scraping the foam from the water surface with a scraping device to achieve solid-liquid or liquid-liquid separation. The air flotation water purifier 2 described in this application includes any water treatment equipment that adopts a closed air flotation process for water treatment, and the rotary scraper 3 is used in conjunction with the air flotation water purifier 2.

[0028] The activated water treatment can be to treat water using the magnetic field effect. When water flows perpendicular to the magnetic field lines, the magnetization treatment is completed, and the surface tension of the water treated by the magnetic field is significantly reduced. The surface tension of the water can also be reduced by adding a surfactant. Water with reduced surface tension can significantly improve the hydrophobic properties of fly ash water, making fly ash easily adhered and captured by water. The magnetized water treatment device 5 described in the present application can be a permanent magnet treatment device or an electromagnetic treatment device.

[0029] The surfactant may be a nonionic surfactant or an amphoteric surfactant. The dosing device for adding the surfactant into the dosing barrel 13 may be any type of dosing machine.

[0030] The principle of the utility model is:

[0031] The coalbed methane collected from the gas gathering station or the central processing plant enters the wet dust collector 1 through the air inlet pipe 19. At the same time, the water is pressurized by the water circulation pump 12 and then passes through the magnetized water processor 5 (the magnetized water is called activated water), and also enters the wet dust collector 1. The water is treated by the magnetic field effect to reduce the surface tension of the water, thereby enhancing the adsorption of the water to the fly ash and removing the fly ash from the coalbed methane. In the wet dust collector 1, the gas / liquid is fully in contact, and the activated water wraps the fly ash in the gas phase, and then the fly ash and water settle to the bottom of the dust collector by gravity, and the coalbed methane moves upward and is purified. Coming out from the top of the dust collector, it passes through the purified gas control valve 21 and is transported to the downstream through the discharge pipe 7; the upper part of the wet dust collector 1 is equipped with a pressure gauge 16 and a safety valve 17 to ensure production safety; the accumulated water at the bottom of the wet dust collector 1 is controlled by the liquid level regulating valve 17 (to stabilize the liquid level), and then reduced by the pressure reducing valve 9, and the dissolved gas in the water will generate tiny bubbles and enter the air flotation water purifier 2, and the small bubbles carry the fly ash to the water surface, and are scraped to its slag collection tank by the rotary scraper 3, and then pressurized by the filter pressure pump 18 into the plate and frame filter press 4, and finally the fly ash is removed; the purified water is pressurized and circulated by the water circulation pump 12. Due to the large difference in the mineralization of produced water under different coal seam conditions, the effect of magnetization on reducing the surface activity of water is different. Therefore, a surfactant can also be added to the water through a dosing device to reduce the surface tension of the water, activate the water, thereby enhancing the adhesion of water to the fly ash, and removing the fly ash from the coalbed methane.

[0032] It should be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0033] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fly ash removal system for coal bed methane production, characterized in that: It comprises a wet dust collector (1), an air flotation water purifier (2), a rotary scraper (3), a plate and frame filter press (4), a magnetized water treatment device (5) and a dosing device (6); The wet dust collector (1) is connected to an air intake pipe (19), and an air intake control valve (20) is provided on the air intake pipe (19). A discharge pipe (7) is provided on the top of the wet dust collector (1), and a purified air control valve (21) is provided on the discharge pipe. The bottom of the wet dust collector (1) is connected to the air flotation water purifier (2) through a first pipeline (8), and a pressure reducing valve (9) is provided on the first pipeline (8). The rotary scraper (3) is arranged above the air flotation water purifier (2). The plate and frame filter press (4) is connected to the air flotation water purifier (2) through a first pipeline (8). The second pipeline (10) is connected to the slag collecting tank of the rotary scraper (3), and the suspended foam on the surface of the air flotation water purifier (2) is scraped into the plate and frame filter press (4) through the rotary scraper (3). The lower part of the rotary scraper (3) is connected to the wet dust collector (1) through the third pipeline (11). A water circulation pump (12) is connected to the third pipeline (11) near the rotary scraper (3), and a magnetized water treatment device (13) is connected to the third pipeline (11) near the wet dust collector (1); The dosing device (6) is arranged beside the air flotation water purifier (2), and a surfactant is added to the air flotation water purifier (2) through the dosing device (6).

2. A fly ash removal system for coal bed methane production according to claim 1, characterized in that: The dosing device (6) comprises a dosing barrel (601), a stirring mechanism is arranged inside the dosing barrel (601), the dosing barrel (601) is connected to the air flotation water purifier (2) via a fourth pipeline (14), and a dosing pump (602) is connected to the fourth pipeline (14).

3. A fly ash removal system for coal bed methane production according to claim 2, characterized in that: The upper part of the wet dust collector (1) is connected to a safety valve (15) and a pressure gauge (16).

4. A fly ash removal system for coal bed methane production according to claim 3, characterized in that: The first pipeline (8) is also connected to a liquid level regulating valve (17), and the liquid level regulating valve (17) is located between the wet dust collector (1) and the pressure reducing valve (9).

5. A fly ash removal system for coal bed methane production according to claim 4, characterized in that: The second pipeline (10) is connected to a filtering pressure pump (18).

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