Low-energy-consumption biogas treatment device

Abstract

The utility model relates to a low-energy-consumption biogas treatment device and belongs to the field of sewage treatment. Comprising a biogas generation device, an alkaline washing tower, a biogas dehydration tank and a biogas delivery pump, the biogas generation device is connected with the middle part of the alkaline washing tower, the top of the alkaline washing tower is connected with the biogas dehydration tank, the biogas dehydration tank is connected with the biogas delivery pump, and the biogas delivery pump is connected with a boiler fuel gas line through a delivery pipeline; a pressure sensor is arranged on the delivery pipeline and is electrically connected with the methane delivery pump. According to the device disclosed by the utility model, the biogas is fully utilized, waste gas in the biogas is well treated, the alkaline washing tower is transformed, sulfide in the biogas is better removed by the alkaline washing tower, the blockage of a spraying opening and the treatment cost of waste alkali are reduced, the operation stability of the device is improved, and the operation cost is reduced.

Description

Technical Field

[0001] The utility model relates to a low-energy consumption biogas treatment device, belonging to the field of sewage treatment. Background Art

[0002] The internal circulation anaerobic reactor is a highly efficient method for treating high-concentration sewage. The principle is that after the high-concentration sewage enters the bottom of the reactor, it is fully contacted with the granular sludge and flocculent sludge bed at the bottom of the reactor under the circulation and agitation of the water flow. Various microorganisms in the sludge come into contact with the organic matter in the sewage and adsorb and decompose the organic matter. The microorganisms produce biogas while degrading the organic matter, thereby achieving the purpose of reducing the concentration of organic matter in the sewage.

[0003] The methane content of biogas produced by anaerobic reactors exceeds 90%, resulting in a high calorific value. This allows it to replace pulverized coal and improve boiler thermal efficiency. However, the composition of the biogas produced, besides methane, varies depending on the nature of the wastewater treated by the anaerobic reactor. Our plant's high-concentration wastewater contains a high sulfate content, resulting in a high sulfur content in the biogas. Sulfides can corrode materials such as rubber, posing a safety hazard to the stable operation of the plant.

[0004] The main way to process biogas is to send it to a gas holder. The sulfides in the biogas corrode the rubber material in the gas holder, posing a safety hazard during operation. Therefore, it needs to be desulfurized in an alkali scrubber before it can be sent to the gas holder for treatment. The desulfurization method of the biogas alkali scrubber is to use sodium hydroxide for absorption desulfurization. During actual operation, it is necessary to replenish a large amount of sodium hydroxide lye from time to time, and continuously replace the waste lye in the tower to maintain a certain lye concentration in the tower to ensure the desulfurization effect of the biogas. This operation not only consumes a large amount of lye and industrial water, but the waste lye generated also needs to be neutralized with sulfuric acid, which consumes a lot of energy and materials. At the same time, the spray heads of the alkali scrubber are frequently clogged with sulfides, which is very troublesome, time-consuming and labor-intensive to clean. Since hydrogen sulfide is toxic, there is also a risk of personnel poisoning, which is not conducive to the safe and stable operation of the device. Summary of the Invention

[0005] According to the background problem, the problem to be solved by the present invention is:

[0006] Biogas contains high levels of sulfur, mostly in the form of hydrogen sulfide. Hydrogen sulfide corrodes rubber and pipelines and is prone to leakage, posing a hazard to plant operation. However, existing alkali scrubbers consume a lot of alkali solution, have irregular replenishment schedules, and easily clog spray nozzles.

[0007] To achieve the above purpose, the present invention provides the following technical solutions:

[0008] A low-energy biogas processing device includes a biogas generator, an alkali scrubber, a biogas dehydration tank, and a biogas delivery pump. The biogas generator is connected to the middle of the alkali scrubber, the top of the alkali scrubber is connected to the biogas dehydration tank, the biogas dehydration tank is connected to the biogas delivery pump, and the biogas delivery pump is connected to a boiler fuel gas line via a delivery pipeline. A pressure sensor is provided on the delivery pipeline, electrically connected to the biogas delivery pump. By altering the process, the biogas is delivered to the boiler as fuel gas and then undergoes secondary waste treatment in the boiler's flue gas treatment section, allowing the generated biogas to be fully utilized.

[0009] Preferably, an on-site combustible material detection alarm is provided in the device.

[0010] Preferably, the alkali washing tower adopts sodium hydroxide solution as alkali washing liquid, and the biogas generating device is connected to the alkali washing tower through a conveying pipeline, and the conveying pipeline is arranged from top to bottom at the tail end of the alkali washing tower, and has an angle of 10-80 degrees with the tower wall of the alkali washing tower; a flushing water spray line is provided at the top inside the alkali washing tower, the alkali washing tower kettle is connected to the industrial water replenishment line, and the flushing water spray line is connected to the industrial water replenishment line; an alkali liquid spray line is provided below the flushing water spray line, and the bottom of the alkali washing tower is connected to an alkali liquid circulation pump, and the alkali liquid circulation pump outlet is divided into an alkali liquid circulation line and a waste alkali liquid external delivery line, the alkali liquid circulation line is connected to the alkali liquid spray line and the tail end of the conveying pipeline, and the alkali liquid circulation line and the waste alkali external delivery line are provided with a control valve; the alkali washing tower kettle is provided with a liquid level meter and a pH analyzer, the alkali washing tower kettle is connected to an alkali liquid replenishment line, and both the industrial water replenishment line and the alkali liquid replenishment line are provided with a control valve.

[0011] The utility model desulfurizes and dehydrates the biogas and sends it to the boiler as fuel gas, so that the biogas is fully utilized. At the same time, the flue gas treatment section of the boiler can be used to treat the waste gas and impurities that are not removed from the biogas, without the need for secondary waste treatment of the biogas.

[0012] By modifying the transmission pipeline connected to the alkali washing tower and connecting the circulating alkali liquid line to the tail of the transmission pipeline, the circulating alkali liquid and biogas are mixed and desulfurized for the first time at the inlet of the alkali washing tower. Because the circulating alkali liquid line has a thick diameter and a large flow rate, it will not be blocked by sulfides and can absorb most of the hydrogen sulfide, reducing the burden on the alkali liquid spray line and greatly alleviating the blockage of the alkali liquid spray line.

[0013] By adding control valves and electrically connecting them to the liquid level gauge and pH analyzer, a rational and highly automated alkali replenishment control system is established. The pH analyzer regularly measures the alkali pH and controls the control valve on the alkali replenishment line, allowing for continuous or indirect alkali replenishment to maintain pH. When the liquid level measured by the level gauge reaches the set value, the pH analyzer is activated to close the alkali replenishment line. Once the circulating alkali reaches neutralization and reaches the set value, the waste alkali collection line is opened and sent to wastewater treatment. When the level gauge drops to the set minimum, the pH analyzer controls the alkali replenishment line and the water replenishment line to replenish the circulating alkali. The pH analyzer ensures that the alkali concentration is neither too high nor too low (an excessive concentration could corrode equipment, while an excessive concentration could reduce absorption). It also ensures that the discharged waste alkali is closer to neutralization, reducing post-discharge treatment costs.

[0014] The beneficial effects of the utility model are:

[0015] The utility model not only makes full use of biogas, but also solves the problem of waste gas in biogas very well, transforms the alkali washing tower, makes the alkali washing tower better remove sulfide in biogas, reduces the blockage of spray port and the treatment cost of waste alkali, improves the stability of device operation and reduces the operation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of biogas treatment device

[0017] Figure 2 Detailed schematic diagram of the alkali washing tower

[0018] In the figure: 1 is a biogas generation device; 2 is an alkali washing tower; 3 is a biogas dehydration tank; 4 is a biogas delivery pump; 5 is a boiler; 6 is a delivery pipeline; 7 is a biogas delivery pump outlet valve; 8 is a pressure sensor; 9 is an on-site combustible detection alarm; 11 is a delivery pipeline; 21 is a flushing water spray line; 22 is an alkali solution spray line; 23 is an alkali solution circulation pump; 24 is an alkali solution circulation line; 25 is a waste alkali solution delivery line; 26 is an industrial water replenishment line; 27 is an alkali solution replenishment line; 28 is a pH analyzer; 29 is a liquid level gauge; 30 is a control valve. DETAILED DESCRIPTION

[0019] Example 1

[0020] A low-energy biogas processing device includes a biogas generating device 1, an alkali scrubbing tower 2, a biogas dehydration tank 3, and a biogas exporting pump 4; the biogas generating device 1 is connected to the middle of the alkali scrubbing tower 2, the top of the alkali scrubbing tower 2 is connected to the biogas dehydration tank 3, the biogas dehydration tank 3 is connected to the biogas exporting pump 4, and the biogas exporting pump 4 is connected to the boiler fuel gas line via an exporting pipeline 6; a pressure sensor 8 is provided on the exporting pipeline 6, and the pressure sensor 8 is electrically connected to the biogas exporting pump outlet valve 7.

[0021] An on-site combustible material detection alarm 9 is provided in this device.

[0022] The alkali washing tower 2 uses sodium hydroxide solution as the alkali washing liquid. The biogas generating device 1 is connected to the alkali washing tower 2 through a conveying pipeline 11. The tail of the conveying pipeline 11 connected to the alkali washing tower 2 is arranged from top to bottom and has an angle of 10-80 degrees with the tower wall of the alkali washing tower 2. A flushing water spray line 21 is provided at the top of the alkali washing tower 2. The kettle of the alkali washing tower 2 is connected to the industrial water replenishment line 26. The flushing water spray line 21 is connected to the industrial water replenishment line 26. An alkali solution spray line 22 is provided below the flushing water spray line 21. The bottom of the alkali washing tower 2 is connected to an alkali liquid circulation pump 23, and the outlet of the alkali liquid circulation pump 23 is divided into an alkali liquid circulation line 24 and a waste alkali liquid delivery line 25. The alkali liquid circulation line 24 is connected to the alkali liquid spray line 22 and the tail end of the conveying pipeline 11. The alkali liquid circulation line 24 and the waste alkali delivery line 25 are provided with a control valve 30; the kettle of the alkali washing tower 2 is provided with a liquid level meter 29 and a pH analyzer 28, and the kettle of the alkali washing tower 2 is connected to an alkali liquid replenishment line 27, and the industrial water replenishment line 26 and the alkali liquid replenishment line 27 are both provided with a control valve 30.

[0023] The utility model not only makes full use of biogas, but also solves the problem of waste gas in biogas very well, transforms the alkali washing tower, makes the alkali washing tower better remove sulfide in biogas, reduces the blockage of spray port and the treatment cost of waste alkali, improves the stability of device operation and reduces the operation cost.

Claims

1. A low-energy consumption biogas treatment device, characterized in that: The invention comprises a biogas generating device (1), an alkali washing tower (2), a biogas dehydration tank (3), and a biogas exporting pump (4); the biogas generating device (1) is connected to the middle of the alkali washing tower (2); the top of the alkali washing tower (2) is connected to the biogas dehydration tank (3); the biogas dehydration tank (3) is connected to the biogas exporting pump (4); the biogas exporting pump (4) is connected to a boiler fuel gas line via an exporting pipeline (6); a pressure sensor (8) is provided on the exporting pipeline (6); and the pressure sensor (8) is electrically connected to an outlet valve (7) of the biogas exporting pump.

2. A low-energy consumption biogas treatment device according to claim 1, characterized in that: The device is provided with an on-site combustible material detection alarm (9).

3. The low-energy biogas treatment device according to claim 1, characterized in that: The alkali washing tower (2) uses sodium hydroxide solution as the alkali washing liquid. The biogas generating device (1) is connected to the alkali washing tower (2) via a conveying pipeline (11). The tail portion of the conveying pipeline (11) connected to the alkali washing tower (2) is arranged from top to bottom and has an angle of 10-80 degrees with the wall of the alkali washing tower (2). A flushing water spray line (21) is provided at the top of the alkali washing tower (2). The kettle of the alkali washing tower (2) is connected to an industrial water replenishment line (26). The flushing water spray line (21) is connected to the industrial water replenishment line (26). An alkali solution spray line (22) is provided below the flushing water spray line (21). The bottom of the tower (2) is connected to an alkali liquid circulation pump (23), the outlet of the alkali liquid circulation pump (23) is divided into an alkali liquid circulation line (24) and a waste alkali liquid delivery line (25), the alkali liquid circulation line (24) is connected to the alkali liquid spraying line (22) and the tail end of the conveying pipeline (11), and the alkali liquid circulation line (24) and the waste alkali delivery line (25) are provided with a control valve (30); the tower kettle of the alkali washing tower (2) is provided with a liquid level meter (29) and a pH analyzer (28), the tower kettle of the alkali washing tower (2) is connected to an alkali liquid replenishment line (27), and the industrial water replenishment line (26) and the alkali liquid replenishment line (27) are both provided with a control valve (30).

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