A landfill gas pressure and methane concentration automatic adjustment system and method

Abstract

The present invention belongs to the technical field of landfill gas treatment, and specifically relates to a landfill gas pressure and methane concentration automatic regulation system and method, the system comprising a landfill, a landfill gas collection system, a methane concentration automatic regulation system, a landfill gas pretreatment system, a landfill gas pressure automatic regulation system, landfill gas utilization equipment and a control module; the landfill gas collection system is constructed on the landfill; the landfill gas collection system is connected to the methane concentration automatic regulation system and the landfill gas pretreatment system in sequence; the landfill gas pretreatment system is connected to the landfill gas pressure automatic regulation system and the landfill gas utilization equipment in sequence. The present invention can realize the automatic regulation of the pressure and methane concentration of the landfill gas during the utilization process, ensure the stable operation of the landfill gas utilization equipment, and improve the utilization efficiency of the landfill gas.

Description

Technical Field

[0001] The invention belongs to the technical field of landfill gas treatment, and in particular relates to a system and method for automatically regulating landfill gas pressure and methane concentration. Background Art

[0002] Landfill gas is the product of a series of degradation reactions after long-term accumulation of garbage. If it is directly discharged into the atmosphere, it will not only damage the ecological environment, but also easily cause fires, so it needs to be treated centrally. The main component of landfill gas is methane, so it is a combustible gas. It is generally directly processed through a torch, used for boiler combustion, or for power generation. However, the current technology is not efficient in utilizing landfill gas, mainly because landfill gas is affected by many factors during the utilization process, such as pressure, methane concentration, temperature, water content, and purity. The above factors all need to be pretreated by landfill gas to achieve the optimal combustion value. In the currently commonly used landfill gas pretreatment system, the stability of pressure and methane concentration during the landfill gas utilization process is not easy to adjust, resulting in unstable operation and low utilization efficiency. For example, when multiple boiler equipment are running together, if one of the boiler equipment is suddenly shut down or due to other landfill gas users, the pressure fluctuation of the landfill gas is large, resulting in the flameout of the boiler burner, explosion, equipment shutdown, and difficulty in starting the equipment. The most commonly used pressure stabilizing equipment is the gas cabinet, but the investment cost is relatively high, and it occupies a large area, which has certain limitations. In addition, the ambient temperature, weather conditions, seasonal changes, and the composition of landfill waste will affect the methane concentration in landfill gas, and changes in methane concentration will directly affect the utilization efficiency of landfill gas. For example, when the methane concentration becomes low, it will cause the boiler burner to shut down, the equipment to be difficult to start, and even burst after multiple attempts to start; when the methane concentration becomes high, the landfill gas will not burn fully, and the harmful gases in the exhaust will aggravate environmental pollution. At the same time, bursting will also occur, posing a safety hazard. Therefore, it is necessary to develop new technical routes to improve the utilization efficiency of landfill gas. Summary of the invention

[0003] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a landfill gas pressure and methane concentration automatic regulation system and method, so as to realize the automatic regulation of landfill gas pressure and methane concentration during the utilization process, ensure the stable operation of landfill gas utilization equipment, and improve the utilization efficiency of landfill gas.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention provides a landfill gas pressure and methane concentration automatic regulation system, comprising a landfill, a landfill gas collection system, a methane concentration automatic regulation system, a landfill gas pretreatment system, a landfill gas pressure automatic regulation system, landfill gas utilization equipment and a control module; the landfill gas collection system is constructed on the landfill to collect the landfill gas generated by the landfill; the landfill gas collection system is connected with the methane concentration automatic regulation system and the landfill gas pretreatment system in sequence, the methane concentration automatic regulation system is used to automatically regulate the methane concentration in the landfill gas, and the landfill gas pretreatment system is used to purify the landfill gas; the landfill gas pretreatment system is connected with the landfill gas pressure automatic regulation system and the landfill gas utilization equipment in sequence, the landfill gas pressure automatic regulation system is used to automatically regulate the landfill gas pressure, and the control module is respectively connected with the methane concentration automatic regulation system, the landfill gas pretreatment system, the landfill gas pressure automatic regulation system and the landfill gas utilization equipment.

[0006] Furthermore, the methane concentration automatic regulating system includes a mechanical three-way valve, an electric regulating valve and a methane concentration automatic regulating pipeline; the electric regulating valve is installed on the methane concentration automatic regulating pipeline, and one end of the methane concentration automatic regulating pipeline is connected to the mechanical three-way valve.

[0007] Furthermore, the landfill gas collection system includes a gas collecting well, a new gas collecting well, an abandoned gas collecting well and a landfill gas transmission pipeline; the gas collecting well is connected to the landfill gas transmission pipeline, the new gas collecting well is respectively connected to the methane concentration automatic regulating pipeline and the landfill gas transmission pipeline through a mechanical three-way valve, the abandoned gas collecting well is connected to the methane concentration automatic regulating pipeline, and the landfill gas transmission pipeline is connected to the methane concentration automatic regulating pipeline; the landfill gas transmission pipeline is connected to the inlet of the landfill gas pretreatment system, and the connection point between the landfill gas transmission pipeline and the methane concentration automatic regulating pipeline is located in front of the connection point between the landfill gas transmission pipeline and the inlet of the landfill gas pretreatment system.

[0008] Furthermore, the landfill gas pretreatment system includes a flame arrester 1, an electric shut-off valve, a coarse filter, an air-water heat exchanger, an air-water separation device, a pressurizing device, a radiator, a fine filter, a desulfurization device and a flame arrester 2. The landfill gas inlet of the flame arrester 1 is connected to the landfill gas transmission pipeline, and the landfill gas outlet of the flame arrester 1 is connected to the electric shut-off valve, the coarse filter, the air-water heat exchanger, the air-water separation device, the pressurizing device, the radiator, the fine filter, the desulfurization device and the flame arrester 2 in sequence.

[0009] Furthermore, the landfill gas pretreatment system also includes a water collection well, and the coarse filter, gas-water heat exchanger, gas-water separation equipment, radiator, fine filter, and desulfurization equipment are respectively connected to the water collection well.

[0010] Furthermore, the methane concentration automatic adjustment system also includes an online methane analyzer, which is installed on the connecting pipe between the desulfurization equipment and the second flame arrester.

[0011] Furthermore, the automatic landfill gas pressure regulating system comprises an electric switch valve, a self-operated pressure regulating valve and a pressure sensor. The electric switch valve and the self-operated pressure regulating valve are respectively connected in parallel with the boosting equipment, and the pressure sensor is installed on the outlet pipe of the boosting equipment.

[0012] The present invention also provides an automatic adjustment method based on the above landfill gas pressure and methane concentration automatic adjustment system, comprising the following steps:

[0013] Step 1: Collecting landfill gas

[0014] Landfill gas flows to the gas collection wells by means of pressure difference, and then is sent to the landfill gas pretreatment system through the landfill gas transmission pipeline. As time goes by, the gas production of the old gas collection wells gradually decreases, and the methane concentration gradually decreases to an unusable range, forming waste gas collection wells. It is necessary to continue to build new gas collection wells on the new garbage pile.

[0015] Step 2: Automatically adjust the methane concentration in landfill gas

[0016] The control module automatically adjusts the opening of the electric regulating valve installed on the methane concentration automatic adjustment pipeline through PID according to the set methane concentration applicable range and the methane concentration signal fed back by the online methane analyzer, so that the landfill gas with lower methane concentration in the new gas collection well and the waste gas collection well is mixed with the landfill gas in the landfill gas transmission pipeline, thereby realizing automatic adjustment of the methane concentration in the landfill gas;

[0017] Step 3: Pre-treating landfill gas

[0018] The landfill gas is transported to the entrance of the landfill gas pretreatment system through the landfill gas transmission pipeline. The flame arrester 1 at the entrance prevents possible open flames from entering the landfill gas pretreatment system from the air inlet. The landfill gas enters the coarse filter through the electric shut-off valve. The electric shut-off valve cuts off the landfill gas supply when receiving an emergency signal. The coarse filter removes part of the moisture and larger impurity particles in the landfill gas. The filtered landfill gas enters the air-water heat exchanger to cool it down, and then enters the air-water separation equipment to remove most of the moisture in the landfill gas. After the landfill gas is cooled and dehydrated, it enters the booster equipment for pressurization, and the temperature will rise. After entering the radiator for cooling treatment, it is filtered through a fine filter to remove tiny impurity particles and part of the moisture. Finally, it enters the desulfurization equipment to desulfurize the sulfide in the landfill gas. The treated landfill gas enters the landfill gas utilization equipment. Flame arrester 2 is installed at the outlet of the landfill gas pretreatment system to prevent the air intake pipeline of the landfill gas utilization equipment from backfired and entering the landfill gas pretreatment system, which may cause dangerous hidden dangers.

[0019] Step 4: Automatically adjust landfill gas pressure

[0020] Set the action pressure value of the electric switch valve to P1, the action pressure value of the self-operated pressure regulating valve to P2, and the normal use pressure value of the landfill gas to P, where P1>P2>P. When the landfill gas pressure detected by the pressure sensor is less than the P value, the control module frequency-controls the boosting device to increase the pressure to the P value; when the landfill gas pressure detected by the pressure sensor is greater than or equal to the P1 value, the control module controls the electric switch valve to open, so that the pressure at the outlet of the boosting device drops rapidly. When the pressure drops to the P2 value, the control module controls the electric switch valve to close, and at the same time the self-operated pressure regulating valve to open, so that the pressure at the outlet of the boosting device continues to drop to the P value, and then the self-operated pressure regulating valve is closed;

[0021] Step 5: Utilization of landfill gas

[0022] The landfill gas utilization equipment utilizes the landfill gas that has been purified and delivered by the landfill gas pretreatment system to meet the pressure and methane concentration requirements.

[0023] Furthermore, in the initial stage of construction of a new gas-collecting well, the gas volume and methane concentration therein are low and cannot meet the utilization requirements. The mechanical three-way valve is opened, and the new gas-collecting well and the methane concentration automatic regulating pipeline are connected. At the same time, the new gas-collecting well and the waste gas-collecting well are used to adjust the methane concentration in the landfill gas. When the gas volume and methane concentration in the new gas-collecting well meet the utilization requirements, the mechanical three-way valve is switched again, and the connection between the new gas-collecting well and the methane concentration automatic regulating pipeline is closed, and the connection between the new gas-collecting well and the landfill gas transmission pipeline is opened. At this time, only the waste gas-collecting well is used to adjust the methane concentration in the landfill gas.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] In order to solve the problem in the prior art that unstable landfill gas pressure and methane concentration affect the normal operation of landfill gas utilization equipment and cause low landfill gas utilization rate, the present invention proposes a landfill gas pressure and methane concentration automatic adjustment system, and adds a methane concentration automatic adjustment system. The control module uses PID to automatically adjust the opening of the electric control valve installed on the methane concentration automatic adjustment pipeline according to the methane concentration signal fed back by the online methane analyzer, thereby controlling the amount of landfill gas containing low concentration methane input into the landfill gas transmission pipeline from the new gas collection wells and the waste gas collection wells. The present invention rationally utilizes the new gas collection wells and the waste gas collection wells to adjust the methane concentration, which greatly improves the efficiency compared with leaving them idle. The utilization rate of resources is improved and the production cost is reduced; an automatic landfill gas pressure regulating system is added, and the control module automatically adjusts the boosting equipment and the electric switch valve according to the pressure signal fed back by the pressure sensor, and combines with the self-powered pressure regulating valve to realize automatic pressure control, so that the pressure value of the landfill gas meets the use requirements; thereby, the automatic regulation of the landfill gas pressure and methane concentration is realized, the continuous, stable and safe operation of the landfill gas utilization equipment is ensured, and the utilization efficiency of the landfill gas is improved. The landfill gas pressure and methane concentration automatic regulating system of the present invention is simple to operate, reliable in operation, low in investment cost, and beneficial to environmental protection, and can achieve good social and economic benefits, and is worthy of application and promotion in the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0027] Figure 1 is a schematic structural diagram of a system for automatically adjusting landfill gas pressure and methane concentration according to an embodiment of the present invention;

[0028] Figure 2 It is a control principle diagram of the landfill gas pressure and methane concentration automatic regulation system according to an embodiment of the present invention.

[0029] The meanings of the numbers in the figure are:

[0030] 1. Landfill;

[0031] 201. Gas-gathering well, 202. New gas-gathering well, 203. Abandoned gas-gathering well, 204. Landfill gas transmission pipeline;

[0032] 301. Mechanical three-way valve, 302. Electric regulating valve, 303. Online methane analyzer, 304. Methane concentration automatic regulating pipeline;

[0033] 4. Landfill gas pretreatment system, 401. Flame arrester 1, 402. Electric shut-off valve, 403. Coarse filter, 404. Air-water heat exchanger, 405. Air-water separation equipment, 406. Pressurizing equipment, 407. Radiator, 408. Fine filter, 409. Desulfurization equipment, 410. Flame arrester 2, 411. Water collection well;

[0034] 501. Electric switch valve, 502. Self-operated pressure regulating valve, 503. Pressure sensor;

[0035] 6. Landfill gas utilization equipment, 7. Control module. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0037] like Figure 1 and Figure 2 As shown, the automatic regulation system for landfill gas pressure and methane concentration of the present embodiment comprises a landfill 1, a landfill gas collection system, a methane concentration automatic regulation system, a landfill gas pretreatment system 4, a landfill gas pressure automatic regulation system, a landfill gas utilization device 6 and a control module 7; a landfill gas collection system is constructed on the landfill 1, and the landfill gas collection system is used to collect the landfill gas generated by the landfill 1; the landfill gas collection system is connected to the methane concentration automatic regulation system and the landfill gas pretreatment system 4 in sequence, the methane concentration automatic regulation system is used to automatically regulate the methane concentration in the landfill gas, and the landfill gas pretreatment system 4 is used to further purify the landfill gas with adjusted methane concentration; the landfill gas pretreatment system 4 is connected to the landfill gas pressure automatic regulation system and the landfill gas utilization device 6 in sequence, the landfill gas pressure automatic regulation system is used to automatically regulate the landfill gas pressure, and finally transport the treated landfill gas to the landfill gas utilization device 6 for use. The control module 7 is respectively connected to the methane concentration automatic adjustment system, the landfill gas pretreatment system 4, the landfill gas pressure automatic adjustment system and the landfill gas utilization device 6, and the control module 7 monitors and automatically controls the landfill gas pressure and the methane concentration automatic adjustment system. The landfill gas utilization device 6 can be specifically designed according to the needs, such as gas generator set power generation, boiler equipment combustion, etc. In this example, boiler equipment combustion is adopted.

[0038] The methane concentration automatic adjustment system includes a mechanical three-way valve 301, an electric regulating valve 302, a methane concentration automatic adjustment pipeline 304 and an online methane analyzer 303; the landfill gas collection system includes a gas collecting well 201, a new gas collecting well 202, a waste gas collecting well 203 and a landfill gas transmission pipeline 204, wherein the number of the gas collecting well 201, the new gas collecting well 202 and the waste gas collecting well 203 can be designed according to the demand for landfill gas. The gas collecting well 201 is connected to the landfill gas transmission pipeline 204, the new gas collecting well 202 is respectively connected to the methane concentration automatic regulating pipeline 304 and the landfill gas transmission pipeline 204 through the mechanical three-way valve 301, the waste gas collecting well 203 is connected to the methane concentration automatic regulating pipeline 304, the landfill gas transmission pipeline 204 is connected to the methane concentration automatic regulating pipeline 304, the electric regulating valve 302 is installed on the methane concentration automatic regulating pipeline 304, the landfill gas transmission pipeline 204 is connected to the inlet of the landfill gas pretreatment system 4, and the connection point between the landfill gas transmission pipeline 204 and the methane concentration automatic regulating pipeline 304 is located in front of the connection point between the landfill gas transmission pipeline 204 and the inlet of the landfill gas pretreatment system 4; the opening degree of the electric regulating valve 302 can be automatically adjusted by using the control module 7.

[0039] The landfill gas pretreatment system 4 includes a flame arrester 1 401, an electric shut-off valve 402, a coarse filter 403, an air-water heat exchanger 404, an air-water separation device 405, a booster device 406, a radiator 407, a fine filter 408, a desulfurization device 409, a flame arrester 2 410 and a water collection well 411. The landfill gas inlet of the flame arrester 1 401 is connected to the landfill gas delivery pipeline 204, and the landfill gas outlet of the flame arrester 1 401 is connected to the electric shut-off valve 402, The coarse filter 403, the gas-water heat exchanger 404, the gas-water separation device 405, the booster device 406, the radiator 407, the fine filter 408, the desulfurization device 409 and the second flame arrester 410 are connected, and the coarse filter 403, the gas-water heat exchanger 404, the gas-water separation device 405, the radiator 407, the fine filter 408, and the desulfurization device 409 are respectively connected to the water collection well 411, and the outlet of the landfill gas pretreatment system 4 is connected to the landfill gas utilization device 6. The online methane analyzer 303 is installed on the connecting pipe between the desulfurization device 409 and the second flame arrester 410, and is used to feed back the monitored methane concentration signal to the control module 7.

[0040] The automatic landfill gas pressure regulating system includes an electric switch valve 501, a self-operated pressure regulating valve 502 and a pressure sensor 503. The electric switch valve 501 and the self-operated pressure regulating valve 502 are respectively connected in parallel with the boosting device 406, and the pressure sensor 503 is installed on the outlet pipe of the boosting device 406.

[0041] This embodiment also provides an automatic adjustment method based on the above landfill gas pressure and methane concentration automatic adjustment system, comprising the following steps:

[0042] Step S1, collecting landfill gas

[0043] The degradable organic components in the garbage will soon undergo microbial decomposition reactions after being pressed in the landfill. The aerobic and anaerobic microorganisms that decompose the garbage mainly come from the soil of the daily cover layer and the final cover layer, the digested sludge of the wastewater treatment accepted by the landfill, and the recycled leachate, etc., and after a series of aerobic and anaerobic reaction processes, methane and carbon dioxide gases are produced. The leachate from the new landfill area flows into the landfill area below to allow the original old garbage to undergo secondary fermentation and produce more landfill gas. Therefore, it is necessary to arrange some landfill gas collection pipelines in the landfill 1, which flow to the gas collection well 201 with the help of pressure difference, and then are sent to the landfill gas pretreatment system 4 through the landfill gas transmission pipeline 204. As time goes by, the gas production of the old gas collection well 201 gradually declines, and the methane concentration gradually decreases to an unusable range, and becomes a waste gas collection well 203. It is necessary to continue to build a new gas collection well 202 on the new garbage pile to meet the demand for landfill gas consumption.

[0044] It should be noted that, in the initial stage of construction of the new gas-collecting well 202, it takes a certain amount of time for the gas volume and methane concentration therein to reach the utilization requirements (the methane concentration is relatively low). The mechanical three-way valve 301 can be opened, and the new gas-collecting well 202 and the methane concentration automatic regulating pipeline 304 are connected. At the same time, the new gas-collecting well 202 and the waste gas-collecting well 203 are used to regulate the methane concentration in the landfill gas. When the gas volume and methane concentration in the new gas-collecting well 202 reach the utilization requirements, the mechanical three-way valve 301 is switched again, and the connection between the new gas-collecting well 202 and the methane concentration automatic regulating pipeline 304 is closed, and the connection between the new gas-collecting well 202 and the landfill gas transmission pipeline 204 is opened. At this time, only the waste gas-collecting well 203 is used to regulate the methane concentration in the landfill gas.

[0045] Step S2, automatically adjusting the methane concentration in the landfill gas

[0046] The control module 7 compares the set methane concentration applicable range with the methane concentration signal fed back by the online methane analyzer 303, and PID automatically adjusts the opening degree of the electric regulating valve 302 installed on the methane concentration automatic adjustment pipeline 304, so that the landfill gas with lower methane concentration in the new gas collection well 202 and the waste gas collection well 203 is mixed with the landfill gas in the landfill gas transmission pipeline 204, so as to automatically adjust the methane concentration in the landfill gas, ensure the stable operation of the boiler equipment, and improve the utilization rate of the landfill gas. In addition, when the methane concentration in the landfill gas is outside the concentration range required for boiler combustion, the control module 7 controls the boiler equipment to automatically shut down according to the methane concentration signal fed back by the online methane analyzer 303, so as to prevent incomplete combustion or explosion after the boiler equipment fails to start automatically for many times.

[0047] Step S3: Pre-treating landfill gas

[0048] The landfill gas pretreatment system 4 is mainly used for the extraction, purification and metering of landfill gas, and provides a gas source that meets the purification index to the landfill gas utilization equipment 6. The landfill gas treatment process is specifically as follows: the landfill gas is transported to the entrance of the landfill gas pretreatment system 4 through the landfill gas transmission pipeline 204. In order to prevent possible open flames from entering the landfill gas pretreatment system 4 from the air inlet, a flame arrester 401 is installed at the entrance. The landfill gas enters the coarse filter 403 through the electric shut-off valve 402. The electric shut-off valve 402 can cut off the landfill gas supply in time when receiving an emergency signal. The coarse filter 403 removes part of the moisture and larger impurity particles in the landfill gas. The filtered landfill gas enters the air-water heat exchanger 404 to cool it down, and then enters the air-water separation equipment 405 to remove most of the moisture in the landfill gas to prevent large impurities in the landfill gas. A large amount of moisture forms acid with corrosive gas, causing corrosion to equipment and pipelines. After cooling and dehydration, the landfill gas enters the boosting equipment 406 for pressurization, and the temperature will rise. After entering the radiator 407 for cooling treatment, it passes through the fine filter 408 to remove tiny impurity particles and part of the moisture, and finally enters the desulfurization equipment 409 to desulfurize the sulfide in the landfill gas to prevent the formation of acid after the landfill gas is burned, which will corrode the boiler and pipeline equipment. The treated landfill gas enters the landfill gas utilization equipment 6. In addition, a flame arrester 410 is installed at the outlet of the landfill gas pretreatment system 4 to prevent the landfill gas utilization equipment 6 from backfired in the air intake pipeline and enter the landfill gas pretreatment system 4, which may cause dangerous hidden dangers.

[0049] Step S4, automatically adjusting the landfill gas pressure

[0050] The operating pressure value of the electric switch valve 501 is set to P1, the operating pressure value of the self-operated pressure regulating valve 502 is set to P2, and the normal use pressure value of the landfill gas is P, wherein P1>P2>P. Due to the reasons at the landfill gas use end, the landfill gas pressure may be unstable, so the system needs to stabilize the landfill gas pressure.

[0051] When the landfill gas pressure detected by the pressure sensor 503 is less than the P value, the control module 7 frequency-convertingly adjusts the speed of the boosting device 406 to increase the pressure to about the P value; when the landfill gas pressure detected by the pressure sensor 503 is greater than or equal to the P1 value, the boosting device 406 does not respond in time, and the pressure at the outlet of the boosting device 406 increases instantly. The control module 7 controls the electric switch valve 501 to open, so that the pressure at the outlet of the boosting device 406 decreases rapidly. When the pressure decreases to the P2 value, the control module 7 controls the electric switch valve 501 to close, and the self-operated pressure regulating valve 502 to open, so that the pressure at the outlet of the boosting device 406 continues to decrease to the P value, and then the self-operated pressure regulating valve 502 is closed to complete the automatic adjustment of the landfill gas pressure. This embodiment uses a staged adjustment of the landfill gas pressure value. First, the electric switch valve 501 is used to release the pressure, and then the self-operated pressure regulating valve 502 is used to finely adjust the pressure so that the pressure continues to decrease to the preset pressure value.

[0052] Step S5: Utilization of landfill gas

[0053] The landfill gas utilization equipment 6 utilizes the landfill gas that meets the pressure and methane concentration after purification and is delivered by the landfill gas pretreatment system 4. The most common way to utilize landfill gas is to use it for power generation through a gas generator set, or to use boiler equipment for heating, but it is not limited to these two ways.

[0054] The automatic adjustment system and method of the automatic adjustment system for landfill gas pressure and methane concentration of the present invention can realize automatic adjustment of landfill gas pressure and methane concentration, ensure the continuous stable and safe operation of landfill gas utilization equipment 6, improve the utilization efficiency of landfill gas, improve economic benefits, and avoid direct discharge of landfill gas into the atmosphere to cause environmental pollution, which is beneficial to environmental protection. The present invention rationally utilizes the new gas collection well 202 and the waste gas collection well 203 to adjust the methane concentration. Compared with leaving them idle, the resource utilization rate is further improved, and the low-concentration methane produced by the new gas collection well 202 and the waste gas collection well 203 is turned into treasure, thereby reducing production costs.

[0055] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes 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 apparatus.

[0056] Finally, it should be noted that the above is only a preferred embodiment of the present invention, which is only used to illustrate the technical solution of the present invention, and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A landfill gas pressure and methane concentration automatic regulation system, characterized in that: It comprises a landfill, a landfill gas collection system, a methane concentration automatic adjustment system, a landfill gas pretreatment system, a landfill gas pressure automatic adjustment system, a landfill gas utilization device and a control module; the landfill gas collection system is constructed on the landfill to collect the landfill gas generated by the landfill; the landfill gas collection system is sequentially connected to the methane concentration automatic adjustment system and the landfill gas pretreatment system, the methane concentration automatic adjustment system is used to automatically adjust the methane concentration in the landfill gas, and the landfill gas pretreatment system is used to purify the landfill gas; the landfill gas pretreatment system is sequentially connected to the landfill gas pressure automatic adjustment system and the landfill gas utilization device, the landfill gas pressure automatic adjustment system is used to automatically adjust the landfill gas pressure, and the control module is respectively connected to the methane concentration automatic adjustment system, the landfill gas pretreatment system, the landfill gas pressure automatic adjustment system and the landfill gas utilization device; The methane concentration automatic regulating system comprises a mechanical three-way valve, an electric regulating valve and a methane concentration automatic regulating pipeline; the electric regulating valve is installed on the methane concentration automatic regulating pipeline, and one end of the methane concentration automatic regulating pipeline is connected to the mechanical three-way valve; The landfill gas collection system comprises a gas collection well, a new gas collection well, an abandoned gas collection well and a landfill gas transmission pipeline; the gas collection well is connected to the landfill gas transmission pipeline, the new gas collection well is respectively connected to the methane concentration automatic adjustment pipeline and the landfill gas transmission pipeline through a mechanical three-way valve, the abandoned gas collection well is connected to the methane concentration automatic adjustment pipeline, and the landfill gas transmission pipeline is connected to the methane concentration automatic adjustment pipeline; the landfill gas transmission pipeline is connected to the inlet of the landfill gas pretreatment system, and the connection point of the landfill gas transmission pipeline and the methane concentration automatic adjustment pipeline is located in front of the connection point of the landfill gas transmission pipeline and the inlet of the landfill gas pretreatment system; The landfill gas pretreatment system includes a pressurizing device, a desulfurization device and a flame arrester 2; the landfill gas pressure automatic regulation system includes an electric switch valve, a self-operated pressure regulating valve and a pressure sensor, the electric switch valve and the self-operated pressure regulating valve are respectively connected in parallel with the pressurizing device, and the pressure sensor is installed on the outlet pipe of the pressurizing device; The methane concentration automatic adjustment system also includes an online methane analyzer, which is installed on the connecting pipeline between the desulfurization equipment and the second flame arrester.

2. The landfill gas pressure and methane concentration automatic adjustment system according to claim 1, characterized in that: The landfill gas pretreatment system also includes a flame arrester 1, an electric shut-off valve, a coarse filter, an air-water heat exchanger, an air-water separation device, a radiator and a fine filter. The landfill gas inlet of the flame arrester 1 is connected to the landfill gas transmission pipeline, and the landfill gas outlet of the flame arrester 1 is connected to the electric shut-off valve, the coarse filter, the air-water heat exchanger, the air-water separation device, the boosting device, the radiator, the fine filter, the desulfurization device and the flame arrester 2 in sequence.

3. The landfill gas pressure and methane concentration automatic adjustment system according to claim 2, characterized in that: The landfill gas pretreatment system further comprises a water collection well, and the coarse filter, the gas-water heat exchanger, the gas-water separation device, the radiator, the fine filter and the desulfurization device are respectively connected to the water collection well.

4. An automatic adjustment method for the landfill gas pressure and methane concentration automatic adjustment system according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: Collecting landfill gas Landfill gas flows to the gas collection wells by means of pressure difference, and then is sent to the landfill gas pretreatment system through the landfill gas transmission pipeline. As time goes by, the gas production of the old gas collection wells gradually decreases, and the methane concentration gradually decreases to an unusable range, forming waste gas collection wells. It is necessary to continue to build new gas collection wells on the new garbage pile. Step 2: Automatically adjust the methane concentration in landfill gas The control module automatically adjusts the opening of the electric regulating valve installed on the methane concentration automatic adjustment pipeline through PID according to the set methane concentration applicable range and the methane concentration signal fed back by the online methane analyzer, so that the landfill gas with lower methane concentration in the new gas collection well and the waste gas collection well is mixed with the landfill gas in the landfill gas transmission pipeline, thereby realizing automatic adjustment of the methane concentration in the landfill gas; Step 3: Pre-treating landfill gas The landfill gas is transported to the entrance of the landfill gas pretreatment system through the landfill gas transmission pipeline. The flame arrester 1 at the entrance prevents possible open flames from entering the landfill gas pretreatment system from the air inlet. The landfill gas enters the coarse filter through the electric shut-off valve. The electric shut-off valve cuts off the landfill gas supply when receiving an emergency signal. The coarse filter removes part of the moisture and larger impurity particles in the landfill gas. The filtered landfill gas enters the air-water heat exchanger to cool it down, and then enters the air-water separation equipment to remove most of the moisture in the landfill gas. After the landfill gas is cooled and dehydrated, it enters the booster equipment for pressurization, and the temperature will rise. After entering the radiator for cooling treatment, it is filtered through a fine filter to remove tiny impurity particles and part of the moisture. Finally, it enters the desulfurization equipment to desulfurize the sulfide in the landfill gas. The treated landfill gas enters the landfill gas utilization equipment. Flame arrester 2 is installed at the outlet of the landfill gas pretreatment system to prevent the air intake pipeline of the landfill gas utilization equipment from backfired and entering the landfill gas pretreatment system, which may cause dangerous hidden dangers. Step 4: Automatically adjust landfill gas pressure Set the action pressure value of the electric switch valve to P1, the action pressure value of the self-operated pressure regulating valve to P2, and the normal use pressure value of the landfill gas to P, where P1>P2>P. When the landfill gas pressure detected by the pressure sensor is less than the P value, the control module frequency-controls the boosting device to increase the pressure to the P value; when the landfill gas pressure detected by the pressure sensor is greater than or equal to the P1 value, the control module controls the electric switch valve to open, so that the pressure at the outlet of the boosting device drops rapidly. When the pressure drops to the P2 value, the control module controls the electric switch valve to close, and at the same time the self-operated pressure regulating valve to open, so that the pressure at the outlet of the boosting device continues to drop to the P value, and then the self-operated pressure regulating valve is closed; Step 5: Utilization of landfill gas The landfill gas utilization equipment utilizes the landfill gas that has been purified and delivered by the landfill gas pretreatment system to meet the pressure and methane concentration requirements.

5. The automatic adjustment method of the landfill gas pressure and methane concentration automatic adjustment system according to claim 4, characterized in that: In the initial stage of construction of a new gas-collecting well, the gas volume and methane concentration therein are low and cannot meet the utilization requirements. The mechanical three-way valve is opened to connect the new gas-collecting well and the methane concentration automatic regulating pipeline. At the same time, the new gas-collecting well and the waste gas-collecting well are used to adjust the methane concentration in the landfill gas. When the gas volume and methane concentration in the new gas-collecting well meet the utilization requirements, the mechanical three-way valve is switched again, the connection between the new gas-collecting well and the methane concentration automatic regulating pipeline is closed, and the connection between the new gas-collecting well and the landfill gas transmission pipeline is opened. At this time, only the waste gas-collecting well is used to adjust the methane concentration in the landfill gas.

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