Gas guide well non-combustible filler gradient filling and cover layer gas absorption construction method

Abstract

The application relates to the technical field of underground engineering safety and environment, and discloses a gradient filling and covering layer gas absorption construction method for a gas guide well non-combustible filler, which comprises the following steps: arranging a core gas channel inner tube with an inverted drainage bell structure at the lower end, filling inert aggregates in the annular cavity formed between the core gas channel inner tube and the well wall, and injecting liquid to form a dynamic liquid seal ring which can self-adapt to geological subsidence, and arranging a heat pipe to establish a freeze-proof regulation loop using the residual heat of landfill gas. The application avoids the gas side leakage problem caused by the uneven settlement of traditional solid fillers by constructing a dynamic liquid seal ring, and realizes self-cleaning by utilizing the energy of landfill gas to drive the drainage bell structure, so that the solid phase deposition problem inevitably caused in the liquid phase purification scheme is converted into an internal circulation without energy consumption, and the gas guide well system can realize long-term self-maintenance and stable operation in a dynamic geological environment.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of gas guide well non-combustible filler gradient filling and covering layer gas absorption construction method, belong to underground engineering safety and environmental technical field. BACKGROUND

[0002] At present, in the filling of mine goaf or tunnel engineering, the guiding and draining of harmful gas in filling body or loose accumulation body is a long-term challenge. The complexity of its working environment lies in that the filling body itself is a dynamic body continuously and unevenly compacted and settled under the action of ground pressure and self-weight, and the percolate water level in it also fluctuates with seasons. How to ensure the long-term effective operation of gas guide well in such a dynamically changing environment is a problem that the field has been concerned about.

[0003] To realize the collection and purification of landfill gas, the current commonly used technical method is to fill solid functional fillers such as gravel or activated carbon in the gas guide well. This method relies on a static and solidified physical structure. When it is directly applied to the above dynamic landfill environment, the mismatch between the structure design and the reality of operation will lead to a series of problems: the small settlement of the filling body may form bypass gaps between the solid filler layers, causing the gas to bypass the treatment layer and escape directly; and the change of the internal groundwater level will cause the functional fillers to be blocked due to immersion or lose their reactivity due to drying and dehydration.

[0004] Although the industry tries to cope by developing solid fillers with better performance, this improvement idea does not change the nature of the static physical structure, so it still cannot effectively solve the functional failure problem caused by the mismatch between the structure and the environment. Specifically, the existing technology mainly has the following problems: 1. There is mechanical incompatibility between the fixed filling structure and the dynamic filling body compaction settlement, which will cause physical damage to the well body seal over time, causing disordered gas leakage; 2. The purification function of solid fillers is highly sensitive to the humidity environment in the well, and it is difficult to maintain long-term stability under the realistic condition of liquid level fluctuation; 3. The accumulation of solid products produced by the purification reaction at the bottom of the well will cause gas passage blockage, which constitutes a deterministic risk of long-term failure of the gas guide system function. Therefore, how to provide a construction method for gas guide well, so as to construct an in-situ gas treatment structure that can not only adapt to geological settlement, but also realize long-term self-cleaning and all-weather stable operation by using the energy of the system itself, has become a technical problem to be solved by the present application. SUMMARY

[0005] The present application provides a kind of gas guide well non-combustible filler gradient filling and covering layer gas absorption construction method, which mainly aims to solve the problem that the static filling structure used in the existing gas guide well construction method cannot adapt to the dynamic settlement of filling body and the change of environmental temperature and humidity, leading to gas side leakage, filler failure and long-term blockage.

[0006] To achieve the above objectives, the present invention provides a method for constructing a gas-guiding well with gradient filling of non-combustible filler and gas absorption of the capping layer, comprising the following steps:

[0007] Step a: Inside the gas well hole, a core gas channel inner tube is laid along its central axis, and the lower end of the core gas channel inner tube is constructed into an inverted diversion bell structure. The lower edge of the diversion bell and the bottom of the gas well hole are kept at a distance that can generate an air lift effect to draw up the bottom sediment when the landfill gas passes through.

[0008] Step b: Fill the annular cavity formed between the inner tube of the core airway and the well wall of the air delivery well with inert aggregate.

[0009] Step c: Inject liquid into the annular cavity until the liquid surface forms a continuous dynamic liquid seal ring in the annular cavity. The height of the dynamic liquid seal ring is sufficient to generate hydrostatic pressure to resist the leakage pressure of harmful gases from the well wall.

[0010] Step d: Install a heat pipe, one end of which is connected to the warm landfill gas area inside the gas well hole, and the other end opens into the liquid surface area of ​​the dynamic liquid seal ring.

[0011] Step e, establish an antifreeze control based on ambient temperature, which includes: based on a temperature threshold higher than the freezing point of the liquid, when the monitored ambient temperature is lower than the temperature threshold, control the heat pipe to be intermittently turned on so as to introduce warm gas from the depth of the stack into the upper liquid of the dynamic liquid seal ring for heating.

[0012] Step f involves leading the upper end of the core airway tube out of the surface cover.

[0013] Preferably, the liquid injected in step c can be treated mine water or on-site circulating water to achieve on-site recycling of water resources.

[0014] Preferably, the method further includes a closed-loop control step for liquid-phase reaction efficiency, which includes: installing an inlet gas sensor and an outlet gas sensor at the inlet and outlet ends of the core airway inner tube, respectively; and calculating the instantaneous purification efficiency η in real time based on the target pollutant inlet concentration measured by the inlet gas sensor and the target pollutant outlet concentration measured by the outlet gas sensor, wherein the calculation rule is as follows: ,in, For the target pollutant inlet concentration, The target pollutant outlet concentration; and the calculated instantaneous purification efficiency. When the efficiency falls below an efficiency threshold corresponding to a statutory emission standard or process stability requirement, the addition of reaction agents to the dynamic liquid seal ring is automatically triggered.

[0015] Preferably, the method further comprises a pre-warning and buffering step for coping with transient gas pressure pulse, which comprises: installing an acoustic sensor at the upper end of the pipe in the core gas channel; and filling a layer of elastic porous medium made of scrap tire fragments above the liquid surface of the dynamic liquid seal ring; the acoustic sensor is used to monitor the acoustic signal of the gas column in the pipe and output a pre-warning signal when identifying the acoustic characteristics corresponding to the transient gas pressure pulse; the elastic porous medium layer is used to provide a buffer space for the liquid being jacked when the transient gas pressure pulse occurs.

[0016] Preferably, the step of identifying the acoustic characteristics corresponding to the transient gas pressure pulse comprises: performing spectral analysis on the acoustic signal, and identifying the acoustic characteristics as the event of the resonance base frequency of the gas column in the pipe in the core gas channel appearing to drift as a Helmholtz resonant cavity.

[0017] Preferably, the method further comprises a step of maintaining the liquid level height of the dynamic liquid seal ring, which comprises: setting a liquid level sensing device and an automatic replenishing device; monitoring the liquid level height of the dynamic liquid seal ring in real time through the liquid level sensing device; and starting the automatic replenishing device to replenish the liquid when the liquid level height is below a safe lower limit for maintaining effective sealing function.

[0018] Preferably, the method further comprises a step of adding a reaction reagent to the dynamic liquid seal ring, the reaction reagent being selected from at least one of an alkaline reagent and an iron salt reagent.

[0019] Preferably, in step a, the spacing is five to ten centimeters.

[0020] Preferably, in step b, the particle size of the inert aggregate is fifty to eighty millimeters.

[0021] Preferably, in step e, the step of controlling the heat guide pipe to be intermittently turned on comprises, in each time of turning on, passing the warm landfill gas into the upper layer of liquid for a time sufficient to raise the temperature of the upper layer of liquid above the temperature threshold, and automatically turning off after the time is reached.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] 1. The method constructs a structure combining a core gas channel and a dynamic liquid seal ring, the effectiveness of the gas sealing no longer depends on the static physical rigidity of the filling medium, but is derived from the inherent self-leveling and continuous distribution characteristics of the liquid phase medium in the gravitational field; when the filling body around the well body deforms due to uneven settlement, the liquid seal ring can autonomously redistribute and continuously fill the small gaps generated by the deformation, so that the physical channel for lateral gas leakage cannot be formed, which eliminates the structural restriction between the reliability of long-term sealing of the well body and the geological dynamic stability, so that the sealing function can be maintained in the continuously changing engineering environment.

[0024] 2. By constructing the combination structure of the core air channel inner tube and the dynamic liquid seal ring, the problem of gas side leakage caused by the bypass gap due to uneven settlement of the filling body in the traditional solid filler is avoided; and the lower end of the core air channel inner tube is constructed into an inverted drainage bell structure, and the gas lifting effect is formed by using the rising energy of the landfill gas, which converts a solid deposition process that inevitably leads to blockage in the liquid purification scheme into a continuous self-cleaning cycle using the energy of the landfill gas itself and without external power input, so that the entire gas guide well system is transformed from a consumable that needs high-cost physical intervention into a facility that can realize long-term stable operation in a dynamic geological environment.

[0025] 3. The present application not only realizes self-adaptation to the dynamic settlement of the landfill by establishing a dynamic liquid seal ring, but also converts the warm landfill gas that inevitably exists in the deep part of the landfill and is ignored by the traditional method into an internal energy source for precise heating of the surface layer of the liquid seal ring by laying heat pipes and establishing an anti-freezing control based on the ambient temperature. This internal recycling of energy enables the present application to cope with the risk of freezing failure of the liquid seal method in cold regions without relying on any external heating energy and chemical antifreeze, thereby improving the running stability of the system in low temperature environment and expanding the geographical application range of the technology in different climate conditions.

[0026] 4. By setting inlet and outlet gas sensors, a closed-loop control mechanism for liquid phase reaction efficiency is established, which no longer attempts to directly measure the liquid itself which is complex in composition and easy to pollute the probe, but instead calculates the concentration difference of the inlet and outlet gas to inversely infer the real-time purification capacity of the liquid seal ring. This change in perspective converts a difficult and unreliable online chemical analysis problem of the liquid phase into a simple and stable physical quantity comparison problem of the gas phase, so that the reagent can be added on demand according to the real reaction consumption rate, avoiding the waste of reagent or the purification failure window period caused by blind addition in the traditional open-loop operation. BRIEF DESCRIPTION OF DRAWINGS

[0027] Fig. 1 The present application is a self-cleaning and purification process flow chart of the gas guide well;

[0028] Fig. 2 The event response and state transition diagram of the automatic operation of the present application system;

[0029] Fig. 3 The collaborative control architecture and information flow diagram of the four core subsystems of the present application. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present application more clear, the technical solutions of the present application will be described in detail below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0031] The present application provides a construction method for gradient filling and covering layer gas absorption of a gas guide well. The method constructs an in-situ gas treatment system which works cooperatively with a central gas channel structure, an annular liquid seal structure, a well bottom sediment transport structure and an environmental adaptability regulation structure. The method is based on the application of physical properties of fluid to replace solid filling medium and the use of part of the energy and heat of landfill gas to construct a gas collection and purification facility which can operate stably for a long time under dynamic geological conditions. In the application environment where the filling body is unevenly settled, the gas guide well using traditional solid filler will form bypass gaps between the fillers when the well body is slightly deformed due to its rigid structure, which will bring the risk of leakage of landfill gas without treatment. To solve this problem, the steps of the construction method start with arranging a core gas channel inner tube along the central axis in the preset gas guide well hole. The inner tube can be made of high-density polyethylene material with corrosion resistance, which provides a specific rising channel for landfill gas from the well bottom to the ground surface. Then, inert aggregates are filled into the annular cavity formed between the core gas channel inner tube and the well wall of the gas guide well hole. The particle size range of the inert aggregates is set to 50-80 mm to form connected voids that can accommodate liquid between the particles, and to form structural support for the core gas channel inner tube and the well wall. After that, liquid is injected into the annular cavity. The liquid can be reclaimed water or leachate in the landfill leachate treatment system, until a continuous dynamic liquid seal ring with a preset height is formed in the annular cavity. The height is set according to the hydrostatic pressure generated by it which is sufficient to resist the lateral seepage pressure of landfill gas. When the well body is displaced due to geological settlement, the liquid level of the liquid seal ring remains horizontal, thereby maintaining the continuous sealing of the lateral leakage channel of the gas.

[0032] Before determining the bottom distance d of the inverted drainage bell, a parameter calibration procedure for the well bottom self-cleaning function needs to be performed. The procedure starts with collecting and analyzing the physical properties of typical solid deposits at the well bottom to obtain the maximum equivalent spherical particle size and the wet density in the leachate ; then, based on the two parameters, a minimum gas lift critical flow rate that is sufficient to overcome the gravity and static friction of the particles is determined through fluid mechanics calculation or by referring to the standard drag force map ; then, the engineering target flow rate is set to apply a dimensionless engineering safety factor of 1.2-1.5 to the critical flow rate the results of the subsequent tests, i.e. Finally, in the field commissioning, the cross-sectional area of the annular gap is changed by adjusting the bottom spacing d , and according to the gas volume flow and the flow rate relationship , the actual flow rate at the gap is made to reach and stabilize at the preset engineering target flow rate , thus completing the configuration of the self-cleaning structure; In the operation process of purifying landfill gas by the liquid seal ring, the reaction reagent added will react with the harmful components in the gas to form solid deposits, and the accumulation of these deposits at the bottom of the well will pose a risk of blocking the entrance of the core gas channel. To suppress this risk, the lower end of the core gas channel inner tube is constructed as an inverted drainage bell structure in the step of laying the core gas channel inner tube, and the lower edge of the drainage bell maintains a preset spacing from the bottom of the gas guide well hole. The spacing calibration process is as follows: based on the gas generation rate under the target working condition, a flow rate is calculated and set which can generate a local negative pressure when the gas passes through the gap, and the negative pressure is sufficient to suck the liquid-solid mixture at the bottom of the well into the gas flow and rise with it. An engineering feasible spacing range is five to ten centimeters. This structure uses the kinetic energy of the rising gas flow to continuously transport the deposits at the bottom of the well to the upper part of the liquid seal ring, avoiding the formation of hard scale at the gas inlet, thus maintaining the long-term unobstructedness of the gas passage.

[0033] At the same time, to deal with the problem that low temperature in winter in cold regions can cause the upper layer of the liquid seal ring to freeze and fail, the construction method also includes laying a heat pipe and establishing a set of anti-freezing control steps based on the ambient temperature. One end of the heat pipe is connected to the warm landfill gas area in the deep part of the gas guide well hole, and the other end is opened in the liquid surface area of the dynamic liquid seal ring. The control logic is as follows: through the temperature sensor set on the ground, the ambient temperature is monitored, and when the temperature is lower than the preset temperature threshold, for example, 2°C, which is higher than the freezing point of the liquid, the control system drives the valve installed on the heat pipe to intermittently conduct, and a small flow of landfill gas carrying the internal heat of the landfill is thus introduced into the upper layer of the liquid seal ring, and through heat exchange, the temperature is maintained above the freezing point, and the step is turned off after a preset time or the temperature rises. This step uses the heat resources of the landfill itself to enable the liquid seal structure to maintain its function in a low-temperature environment. In addition, to achieve cost control and efficiency management of the purification process, the method also establishes a set of closed-loop control steps for the reaction efficiency of the liquid phase. By setting an inlet gas sensor and an outlet gas sensor at the inlet end and the outlet end of the core gas channel inner tube respectively, the concentration of the target pollutant is measured, thus avoiding the difficulty of direct chemical measurement in harsh liquid environments. The control system collects the inlet concentration and the outlet concentration in real time, and according to the calculation rule Achieve instantaneous purification efficiency and the The value corresponds to the efficiency threshold of a statutory emission standard or process requirement. For example, comparing 95%; when Below When the reaction is insufficient, the system determines that the reaction reagent in the liquid-sealed ring is consumed and automatically triggers the dosing device to add a standard metering of reaction reagent, such as an alkaline reagent or an iron salt reagent, to the liquid-sealed ring. This closed-loop control ensures that the reagent is replenished as needed based on the actual reaction consumption rate.

[0034] The parameters in the closed-loop control logic of liquid-phase reaction efficiency are determined through a set of on-site tuning procedures with compliance as the boundary. These procedures are first based on statutory emission limits. With the maximum design exhaust rate of the site Set the maximum allowable pollutant emission exceeding the standard in a single instance of substandard purification efficiency. Subsequently, through a single test dose of the reagent, the concentration of pollutants at the outlet was continuously monitored and plotted. The recovery curve changes over time, and the preset recovery time is calculated based on this curve. This time is defined as the time required to reduce the total amount of emissions exceeding the standard. Just meets the conditions The maximum duration t; finally, the single standard dosage. The standard is set to ensure purification efficiency. Here From below the efficiency threshold within a time period The state recovers to the minimum reagent volume. Simultaneously, to address the inevitable baseline drift and performance degradation issues of sensors during long-term operation, the system incorporates a periodic self-calibration and model correction mechanism. This mechanism is automatically triggered at preset maintenance cycles or when the statistical variance of key sensor output data continuously exceeds its historical baseline by three standard deviations. By comparing the deviation between short-term high-frequency sampling data and long-term moving averages, the inlet concentration measured by the sensor is corrected. and export concentration The baseline is compensated and corrected to ensure instantaneous purification efficiency. The calculations are always based on accurate measurement data, thereby ensuring the long-term effectiveness and decision reliability of the entire closed-loop control system.

[0035] The construction method further comprises a step of coping with transient gas pressure pulse, which is configured to fill a layer of elastic porous medium layer composed of scrap tire fragments above the liquid surface of the dynamic liquid seal ring, and install an acoustic sensor on the upper end of the inner tube of the core gas channel; the acoustic sensor identifies the drift event of the gas column resonance fundamental frequency as a Helmholtz resonance cavity caused by the rising of large-scale gas plug through spectral analysis of the acoustic signal of the gas column in the tube, and outputs it as a warning signal; when the pressure pulse occurs, the liquid that is jacked rushes into the elastic porous medium layer, and the porous structure of the elastic porous medium layer provides a buffer space for the liquid, and the elastic deformation absorbs the impact energy; in order to maintain the stable operation of the system, a liquid level sensing device and an automatic replenishing device can also be provided to supplement the liquid when the liquid surface is below the safe lower limit; finally, the upper end of the inner tube of the core gas channel is led out of the surface cover layer.

[0036] Example 1: In an environment of a completed filling mine goaf, the filling body is unevenly settled under the action of self-weight and ground pressure, the gas guide well originally using solid filler has formed a connected gap between the filler and the well wall due to the deformation of the well body caused by geological stress, landfill gas leaks along this path, and the change of leachate water level causes the filler to be partially submerged or dried, reducing or losing its gas treatment function; after the application of the above construction method, the operation state of the gas guide well is as follows: first, the leachate taken from the field is injected into the annular cavity between the inner tube of the core gas channel and the well wall to form a continuous dynamic liquid seal ring, and the liquid surface of the liquid seal ring remains horizontal in the inclined state of the well body, thereby continuously physically blocking the channel of lateral gas permeation, and all the gas is guided to the lower end inlet of the inner tube of the core gas channel; in order to treat hydrogen sulfide in the gas, a reaction reagent is added to the dynamic liquid seal ring, and the ferrous sulfide solid deposits generated after the reaction of the reaction reagent with the target harmful gas (such as gas, hydrogen sulfide, etc.) accumulate to the bottom of the gas guide well hole under the action of gravity.

[0037] With the accumulation of ferrous sulfide deposits at the bottom of the well, the rising landfill gas passes through the inverted drainage bell structure at the lower end of the inner tube of the core gas channel, the gas flow rate increases in the gap between the structure and the bottom of the well and forms a local negative pressure, which sucks the liquid-solid mixture at the bottom of the well into the bell, and transports it to the middle and upper part of the liquid seal ring by bubble flow, and the transported particles re-settle here. The existence of this transportation process maintains the unobstructedness of the gas inlet, and also provides the gas sensors arranged at the inlet and outlet ends of the core gas channel with gas for effective concentration comparison, so that the instantaneous purification efficiency based on the concentration of the gas sensor at the inlet end of the core gas channel is higher than 99.99%, and the instantaneous purification efficiency based on the concentration of the gas sensor at the outlet end of the core gas channel is higher than 99.99%. The closed-loop regulation step can trigger the dosing device to supplement the reaction reagent according to the real-time change of the hydrogen sulfide concentration. When the surface environmental temperature drops below the freezing point in the low-temperature season, the heat pipe in the system will introduce a temperature-carrying landfill gas from the deep well body into the upper layer of the dynamic liquid seal ring after the temperature control valve is triggered. The heat exchange maintains the temperature of the surface liquid above the freezing point, and the liquid sealing function can continue under low-temperature conditions. The gas guide well system thus stably operates in the interaction with the dynamic environment of the landfill, and the scheduling of internal substances and energy replaces the need for external physical dredging and functional filler replacement.

[0038] Example 2: To verify the sealing effectiveness and purification regulation capacity of the construction method of the application under the conditions of simulated dynamic geological subsidence and continuous pollutant load, a set of physical model comparison tests composed of an experimental group and a control group were established. The test platform is two identical cylindrical containers filled with simulated compacted filling materials. The experimental group container is equipped with the gas guide well system of the application, and the control group is equipped with the gas guide well using traditional gravel fillers. Both containers are connected to a gas injection pipeline at the bottom to introduce simulated landfill gas with known components. The whole container is placed on a hydraulic platform that can be controlled by a program to apply a controllable differential displacement. During the test, a mixture of methane and hydrogen sulfide is introduced into the bottom of the two containers at a constant flow rate, and an initial dose of iron salt reaction reagent is pre-added to the dynamic liquid seal ring of the experimental group. A high-precision methane detector is installed at the top of the container to continuously monitor possible gas side leakage. At the same time, an outlet gas sensor is installed at the outlet end of the two gas guide wells to monitor the hydrogen sulfide concentration in the exhaust gas. The sensor data of the experimental group is connected to a controller for executing closed-loop regulation logic. The efficiency threshold is set to 95%, and the data sampling period is set to 60 seconds. The setting of this period balances the rapid response to gas concentration changes and the load of the data processing system, and the time length is sufficient to capture the dynamic process of efficiency decline due to reagent consumption and efficiency recovery after one closed-loop addition.

[0039] ​After 24 hours of initial stable operation, the hydraulic platform was activated to apply continuous small differential displacements. By the 36th hour of the test, i.e., after 24 hours of simulated settling, the methane leakage concentration at the top of the control group had risen to 158 ppm, while the experimental group's reading remained below the background level of 5 ppm. Observing the change in leakage concentration over time, the control group's data showed a curve that continuously increased from the 24th hour, reaching 950 ppm by the 156th hour, while the corresponding data for the experimental group remained a near-zero flat line throughout the test period. This difference is attributed to the experimental group's dynamic liquid seal ring adaptively adjusting to structural deformation, maintaining the integrity of the seal, while the rigid aggregate packing in the control group formed a through-channel leakage path under displacement. Simultaneously, the purification efficiency data of the experimental group showed that its outlet hydrogen sulfide concentration... During the initial operation phase, the level was maintained below 10 ppm, corresponding to an instantaneous purification efficiency. Above 99%; after running for approximately 84 hours, When the value first dropped to 95.2%, the controller immediately triggered an automatic dosing of the reaction reagent. After the dosing was completed, The value recovered to over 99% within minutes; this process of automatic dosing and rapid recovery triggered by efficiency decline was reproduced again around the 132nd hour. Automatic dosing occurred twice during the entire test cycle, indicating that the closed-loop control step can automatically replenish the reaction agent according to the actual consumption rate of the purification capacity. The test results confirm that, under simulated geological subsidence conditions, the construction method of this invention has reliable engineering feasibility in maintaining the continuous effectiveness of gas sealing and maintaining the stability of gas purification effect through closed-loop control.

[0040] Example 3: This example combines Figs. 1 to 3 This section describes the construction method for gradient filling of non-combustible filler and gas absorption of the caprock in the gas-guiding well. Fig. 1 As shown, the raw gas generated by the landfill gas source first enters the self-cleaning drainage structure at the bottom of the well. This structure utilizes the gas lift effect to transport solid phase deposition to prevent gas channel blockage. Subsequently, the gas enters the dynamic liquid seal ring purification treatment unit, where target pollutants are removed through liquid phase absorption reaction. The purified gas is finally discharged. This core purification process is supported by two closed-loop control systems. One is the liquid phase reaction efficiency closed-loop control system, which calculates the purification efficiency in real time by comparing the readings of the inlet gas sensor and the outlet gas sensor, and triggers the addition of reaction agents as needed based on the calculation results. The other is the ambient temperature adaptive control system, which monitors the ambient temperature and introduces warm landfill gas at low temperatures, using the residual heat of the landfill gas itself to heat the dynamic liquid seal ring to prevent freezing failure.

[0041] like Fig. 2As shown, when the ambient temperature falls below a threshold event, the system enters an anti-freeze heating state, intermittently switching on the heat pipe until heating reaches the preset duration or the temperature recovers, at which point the heat pipe is switched off, returning to stable operation. The instantaneous purification efficiency... When a threshold event occurs, the system triggers the automatic dosing device to replenish the reaction reagent. After the reagent replenishment is completed, monitoring is restored, and the system returns to stable operation. When a liquid level below the safety lower limit event occurs, the system starts the automatic replenishment device to automatically replenish the liquid. Once the liquid level returns to normal, replenishment stops, and the system returns to stable operation. When the system identifies a Helmholtz resonance fundamental frequency drift event, it indicates that there may be a transient pressure pulse, and the system will output a warning signal.

[0042] like Fig. 3 As shown, the 1.0 gas purification and treatment subsystem is the physical core. It directly processes the raw landfill gas and interacts with the landfill environment. It also outputs status information such as purified gas, inlet / outlet gas concentration, and liquid level. The 2.0 purification efficiency control subsystem generates a dosing control signal based on the concentration information and feeds it back to the 1.0 subsystem. It also interacts with the operation and maintenance system / personnel to obtain the reaction reagents. The 3.0 system temperature control subsystem generates a heating control signal based on the ambient temperature obtained from the landfill environment and feeds it back to the 1.0 subsystem. The 4.0 liquid seal level maintenance subsystem generates a liquid replenishment control signal based on the liquid level information and instructs the operation and maintenance system / personnel to replenish the liquid. This forms a complete, autonomous, and collaborative closed-loop control system.

[0043] Example 4: Before a newly built gas-guided well system is put into operation, some structural parameters and algorithm thresholds need to be set to ensure that the system's self-cleaning and early warning functions are adapted to the gas dynamic characteristics of the specific site. The structural parameters involved include the bottom spacing of the inverted drainage bell at the lower end of the core gas channel inner tube, and the algorithm threshold is the trigger condition for transient gas pressure pulse acoustic recognition. The bottom spacing of the inverted drainage bell is set as follows: First, the peak gas volumetric flow rate of the landfill is obtained based on the gas yield model of the landfill. And obtain the physical properties of the water-bearing sediments that may form at the bottom of the well; the calibration target is to set a spacing This allows the gas flow rate to reach At that time, the flow velocity generated by the gas in the annular gap formed between the lower edge of the bell jar and the bottom of the well. It can produce an airlift effect on precipitate particles; its setup process involves adjusting... To change the cross-sectional area of ​​the annular gap and based on The relationship is used to calculate the corresponding gas flow rate. Ultimately, the spacing Fixed at a point that makes the calculated flow rate reaches or exceeds a target flow rate set for generating a gas lift effect .

[0044] For the acoustic identification logic of transient gas pressure pulse, the calibration process is as follows: after the gas guide well system runs continuously at a steady gas flow rate for an initial period, the acoustic signals output by the acoustic sensor on the upper end of the core gas duct during this period are collected and recorded, and the signals are subjected to spectral analysis to extract the time series data of the Helmholtz resonance fundamental frequency of the gas column in the duct; then, the baseline data of the fundamental frequency are subjected to statistical analysis to calculate the mean value and the standard deviation of the fundamental frequency under stable working conditions; the logic rule for early warning triggering is fixed in the monitoring system, and the rule is set as follows: when the real-time monitored fundamental frequency at consecutive sampling points meets the condition , the system determines that the acoustic characteristics corresponding to the transient gas pressure pulse are identified and outputs a warning signal; in a specific configuration, the coefficient is set to 3, and the coefficient is set to 5; after the calibration of the two items is completed, the self-cleaning structure and risk warning logic of the gas guide well system are configured to adapt to the operating state of the specific site conditions.

[0045] Example 5: In a landfill site where the gas guide well system of the present application has been installed and continuously operated, periodic on-site calibration of specific parameters in the automatic control logic of the system is required to cope with seasonal changes in the site environment and long-term evolution of landfill gas components, which involves the anti-freezing control duration of the dynamic liquid seal ring and the single dose amount of the liquid-phase reaction efficiency closed-loop control; to calibrate the single on duration of the anti-freezing control, when the temperature probe arranged in the upper liquid of the dynamic liquid seal ring detects that the liquid temperature drops to the anti-freezing trigger threshold of about 2°C, a manual on of the heat pipe is started to make the landfill gas carrying temperature pass into the upper liquid, and the duration required for the liquid temperature to rise from 2°C to the target temperature of 4°C is recorded ; then, the measured duration is set as the single on duration parameter of the anti-freezing control in the control system.

[0046] To calibrate the single dose amount of the closed-loop control, when the instantaneous purification efficiency drops below the efficiency threshold and triggers an automatic dosing event, a known initial test dose of the reaction reagent is injected into the dynamic liquid seal ring through the dosing device; if the purification efficiency does not rise to the The above, at the next automatic dosing event triggered, with a preset step increase in dosage, repeat this process until a dose is determined , which can be triggered after , within the time , to restore , above, and this dose as the standard dose of the operating cycle within the parameters of the control system to regulate the logic, complete this set of periodic field calibration procedures, the gas guide system is updated to respond to the operating parameters of the current environmental conditions and pollution load.

[0047] Example 6: Before deploying the gas guide system of the present application in a specific site which is assessed to have high gas potential and transient gas pressure pulse risk, a set of standardized pre-parameter optimization procedures need to be performed to set the operating parameters of its passive safety redundancy and core function maintenance; the procedure first sets the thickness of the elastic porous medium layer , whose optimization goal is to determine the minimum thickness under the premise of meeting the safety redundancy, according to the site assessment report to obtain the liquid volume that can be displaced by the maximum credible transient gas pressure pulse , and to determine the effective porosity of the waste tire fragment medium ; the setting of thickness needs to meet the constraint condition , where is the total pore volume provided by the medium layer, whose value is the cross-sectional area of the gas guide well annular cavity , the product of thickness and effective porosity , and is the safety factor, which is 1.5, according to which the minimum value of that meets the constraint condition is calculated and used as the construction parameter.

[0048] The procedure then configures the liquid level automatic replenishment logic of the dynamic liquid seal ring, with the lower limit liquid level being set as the hydrostatic pressure height that can resist the maximum regular lateral gas pressure in the field area, and the upper limit liquid level being set as a certain distance below the bottom of the elastic porous medium layer to reserve gas buffer space; to deal with abnormal working conditions such as sensor failure or well body leakage, a timeout interrupt mechanism is set in the logic, with the maximum allowed continuous replenishment duration , whose value is determined as follows: first, according to the rated flow of the replenishment device and the volume between and , the duration required for normal replenishment is calculated , and then is set as a multiple of the time of continuous operation of the replenishment device, if the time of continuous operation of the replenishment device exceeds The control system then determines that an anomaly has occurred and interrupts the replenishment and issues a warning. After this procedure has been completed, the passive safety parameters and the automated maintenance logic for the particular site are determined and loaded into the control system of the gas guide well system.

[0049] It is apparent for a person skilled in the art that the present application is not limited to the details of the above-described exemplary embodiments, but that the present application can be realized in other concrete forms without departing from the spirit or essential characteristics of the present application.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate but not limit the technical solutions of the present application, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those of ordinary skill in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for constructing a gas-guiding well with gradient filling of non-combustible packing material and gas absorption of the capping layer, characterized in that, Includes the following steps: Step a: Inside the gas well hole, a core gas channel inner tube is laid along its central axis, and the lower end of the core gas channel inner tube is constructed into an inverted diversion bell structure. The lower edge of the diversion bell and the bottom of the gas well hole are kept at a distance that can generate an air lift effect to draw up the bottom sediment when the landfill gas passes through. Step b: Fill the annular cavity formed between the inner tube of the core airway and the well wall of the air delivery well with inert aggregate. Step c: Inject liquid into the annular cavity until the liquid surface forms a continuous dynamic liquid seal ring in the annular cavity. The height of the dynamic liquid seal ring is sufficient to generate hydrostatic pressure to resist the leakage pressure of harmful gases from the well wall. Step d: Install a heat pipe, one end of which is connected to the warm landfill gas area inside the gas well hole, and the other end opens into the liquid surface area of ​​the dynamic liquid seal ring. Step e, establish an antifreeze control based on ambient temperature, which includes: based on a temperature threshold higher than the freezing point of the liquid, when the monitored ambient temperature is lower than the temperature threshold, control the heat pipe to be intermittently turned on so as to introduce warm gas from the depth of the stack into the upper liquid of the dynamic liquid seal ring for heating. Step f involves leading the upper end of the core airway tube out of the surface cover.

2. The method for constructing a gas-guiding well with gradient filling of non-combustible filler and gas absorption of the capping layer according to claim 1, characterized in that, The liquid injected in step c can be treated mine water or on-site circulating water.

3. The method for constructing a gas-guiding well with gradient filling of non-combustible filler and gas absorption of the capping layer according to claim 1, characterized in that, The method also includes a closed-loop control step for liquid-phase reaction efficiency, which includes: installing an inlet gas sensor and an outlet gas sensor at the inlet and outlet ends of the core airway inner tube, respectively; and calculating the instantaneous purification efficiency η in real time based on the target pollutant inlet concentration measured by the inlet gas sensor and the target pollutant outlet concentration measured by the outlet gas sensor, the calculation rule being as follows: ,in, For the target pollutant inlet concentration, The target pollutant outlet concentration; and the calculated instantaneous purification efficiency. When the efficiency falls below an efficiency threshold corresponding to a statutory emission standard or process stability requirement, the addition of reaction agents to the dynamic liquid seal ring is automatically triggered.

4. The method for constructing a gas-guiding well with gradient filling of non-combustible filler and gas absorption of the capping layer according to claim 1, characterized in that, The method also includes an early warning and buffering step for dealing with transient pressure pulses, which includes: installing an acoustic sensor at the upper end of the inner tube of the core airway; and filling an elastic porous medium layer composed of waste tire fragments on the liquid surface of the dynamic liquid seal ring; the acoustic sensor is used to monitor the acoustic signal of the air column in the tube and output an early warning signal when an acoustic feature corresponding to a transient pressure pulse is identified; the elastic porous medium layer is used to provide a buffer space for the liquid being pushed up when a transient pressure pulse occurs.

5. The method for constructing a gas-guiding well with gradient filling of non-combustible filler and gas absorption of the capping layer according to claim 4, characterized in that, The steps for identifying acoustic features corresponding to transient air pressure pulses include: performing spectral analysis on the acoustic signal and identifying the air column in the core airway tube as an event of a drift in the resonant fundamental frequency of the Helmholtz resonant cavity as an acoustic feature.

6. The method for constructing a gas-guiding well with gradient filling of non-combustible filler and gas absorption of the capping layer according to claim 1, characterized in that, The method also includes the step of maintaining the liquid level of the dynamic liquid seal ring, which includes: setting up a liquid level sensor and an automatic replenishment device; monitoring the liquid level of the dynamic liquid seal ring in real time through the liquid level sensor; and activating the automatic replenishment device to replenish liquid when the liquid level is lower than a safe lower limit for maintaining effective sealing function.

7. The method for constructing a gas-guiding well with gradient filling of non-combustible filler and gas absorption of the capping layer according to claim 1, characterized in that, The method further includes the step of adding a reaction agent to the dynamic liquid-sealed ring, the reaction agent being selected from at least one of a basic agent and an iron salt agent.

8. The method for constructing a gas-guiding well with gradient filling of non-combustible filler and gas absorption of the capping layer according to claim 1, characterized in that, In step a, the spacing is five to ten centimeters.

9. The method for constructing a gas-guiding well with gradient filling of non-combustible filler and gas absorption of the capping layer according to claim 1, characterized in that, In step b, the particle size of the inert aggregate is 50 to 80 millimeters.

10. The method for constructing a gas-guiding well with gradient filling of non-combustible filler and gas absorption of the capping layer according to claim 1, characterized in that, Step e, the step of controlling the intermittent conduction of the heat pipe, includes, each time it is conducted, introducing warm landfill gas into the upper liquid for a duration sufficient to raise the temperature of the upper liquid above a temperature threshold, and automatically shutting it off after reaching that duration.

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