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

Abstract

The invention relates to the technical field of underground engineering safety and environment, and discloses a gas guide well non-combustible filler gradient filling and covering layer gas absorption construction method which comprises the steps that a core gas channel inner pipe with an inverted drainage bell jar structure at the lower end is arranged, an annular cavity formed between the core gas channel inner pipe and a well wall is filled with inert aggregate, and liquid is injected; according to the invention, a dynamic liquid seal ring capable of being self-adaptive to geological sedimentation is formed, and meanwhile, a heat pipe is arranged to establish an anti-freezing regulation and control loop utilizing waste heat of landfill gas, so that the problem of gas side leakage caused by non-uniform sedimentation of a filling body of a traditional solid filler is avoided through a mode of constructing the dynamic liquid seal ring; and the drainage bell jar structure is driven by the energy of the landfill gas to realize self-cleaning, so that the solid-phase deposition problem inevitably generated in a liquid-phase purification scheme is converted into 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] This invention relates to a method for gradient filling of non-combustible filler and gas absorption construction of a gas-absorbing cover layer in a gas-guiding well, belonging to the field of underground engineering safety and environmental technology. Background Technology

[0002] Currently, in mine goaf filling or tunnel engineering, the drainage of harmful gases inside the filling body or loose deposits is a long-term challenge. The complexity of the working environment lies in the fact that the filling body itself is a dynamic body that is continuously undergoing uneven compaction and settlement under the action of ground pressure and its own weight. At the same time, the water level of the leachate inside it also fluctuates with the seasons. How to ensure the long-term effective operation of the gas well in such a dynamic environment is an issue of continuous concern in this field.

[0003] To collect and purify landfill gas, the commonly used technique is to fill the gas well with solid functional fillers such as crushed stone or activated carbon. This method relies on a static and solidified physical structure. When it is directly applied to the dynamic landfill environment, the mismatch between its structural design and operational reality can lead to a series of problems: minor settlement of the filling material may form bypass gaps between the solid filler layers, allowing gas to bypass the treatment layer and escape directly; and changes in the internal groundwater level may cause the functional fillers to become blocked due to submersion or lose their reactivity due to drying and dehydration.

[0004] Although the industry has attempted to address this issue by developing more powerful solid packing materials, this approach does not alter the fundamental static physical structure. Therefore, it remains ineffective in resolving functional failures caused by structural and environmental mismatch. Specifically, existing technologies suffer from the following problems: 1. Mechanical incompatibility exists between the fixed packing structure and the dynamic compaction and settlement of the filling material, leading to physical damage to the well seal over time and causing disordered gas leakage; 2. The purification function of solid packing is highly sensitive to the humidity environment within the well, making it difficult to maintain long-term stability under fluctuating liquid levels; 3. The continuous accumulation of solid products generated by the purification reaction at the bottom of the well can cause gas passage blockage, posing a definite risk of long-term failure of the gas guiding system. Therefore, the technical problem this invention aims to solve is to provide a construction method for gas guiding wells that can not only adapt to geological settlement but also utilize the system's own energy to achieve long-term self-cleaning and stable operation across all climates. Summary of the Invention

[0005] This invention provides a method for constructing a gas well with gradient filling of non-combustible filler and gas absorption of the cover layer. Its main purpose is to solve the problem that the static filling structure used in the existing gas well construction method cannot adapt to the dynamic settlement of the filling body and changes in environmental temperature and humidity, resulting in gas 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: 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.

[0007] 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.

[0008] 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.

[0009] Preferably, the method further 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 it identifies the acoustic feature corresponding to the transient pressure pulse; the elastic porous medium layer is used to provide a buffer space for the liquid being supported when the transient pressure pulse occurs.

[0010] Preferably, the step of identifying the acoustic feature corresponding to the transient air pressure pulse includes: performing spectral analysis on the acoustic signal and identifying the air column in the core airway tube as an event in which the resonant fundamental frequency of the Helmholtz resonant cavity drifts as an acoustic feature.

[0011] Preferably, the method further 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.

[0012] Preferably, 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 an alkaline agent and an iron salt agent.

[0013] Preferably, in step a, the spacing is five to ten centimeters.

[0014] Preferably, in step b, the particle size of the inert aggregate is 50 to 80 millimeters.

[0015] Preferably, in step e, the step of controlling the intermittent operation of the heat pipe includes, each time the operation is initiated, introducing warm landfill gas into the upper liquid for a duration sufficient to raise the temperature of the upper liquid to above a temperature threshold, and then automatically shutting off after the duration is reached.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This method constructs a structure combining a core gas channel and a dynamic liquid sealing ring. The effectiveness of its gas sealing no longer depends on the static physical rigidity of the filling medium, but rather on the inherent self-leveling and continuous distribution characteristics of the liquid medium under gravity. When the filling material around the well body deforms due to uneven settlement, the liquid sealing ring can autonomously redistribute and continuously fill the tiny gaps caused by the deformation, preventing the formation of physical channels for lateral gas leakage. This process removes the structural constraint between the reliability of long-term well sealing and geological dynamic stability, enabling the sealing function to be maintained in a continuously changing engineering environment.

[0017] 2. By constructing a combined structure of the core gas channel inner tube and the dynamic liquid seal ring, the gas leakage problem caused by the bypass gaps due to uneven settlement of the filling material in traditional solid packing is avoided. Furthermore, this method further constructs the lower end of the core gas channel inner tube into an inverted drainage bell structure, using the energy of the rising landfill gas to form a gas lift effect. This transforms a solid phase accumulation process that inevitably leads to blockage in liquid phase purification schemes into a continuous self-cleaning cycle that utilizes the energy of the landfill gas itself and requires no external power input. This transforms the entire gas well system from a consumable that requires high-cost physical intervention into a facility that can achieve long-term stable operation in dynamic geological environments.

[0018] 3. This invention not only achieves adaptive response to dynamic settlement of landfills by establishing a dynamic liquid seal ring, but also transforms the warm landfill gas, which is inevitably present deep in the landfill and is ignored by traditional methods, into an internal energy source for precisely heating the surface of the liquid seal ring by deploying heat pipes and establishing antifreeze control based on ambient temperature. This internal energy circulation utilization method enables the invention to help cope with the risk of freezing failure that liquid seal methods may encounter in cold regions without relying on any external heating energy or chemical antifreeze agents, improves the operational stability of the system in low-temperature environments, and expands the geographical applicability of this technology under different climatic conditions.

[0019] 4. By setting up inlet and outlet gas sensors, a closed-loop control mechanism for liquid-phase reaction efficiency was established. This mechanism no longer attempts to directly measure the complex and easily contaminated liquid itself, but instead infers the real-time purification capacity of the liquid-sealed loop by calculating the concentration difference between the inlet and outlet gases. This shift in perspective transforms a difficult and unreliable problem of online liquid-phase chemical analysis into a simple and stable problem of comparing gas-phase physical quantities. This allows for the addition of reagents as needed based on the actual reaction consumption rate, avoiding reagent waste or purification failure windows caused by blind addition in traditional open-loop operations. Attached Figure Description

[0020] Figure 1 This is a process flow diagram of the self-cleaning purification and dual closed-loop control process of the gas well in this invention; Figure 2 This is a diagram showing the event response and state transition of the automated operation of the system of the present invention; Figure 3 This is a diagram showing the collaborative control architecture and information flow of the four core subsystems of this invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0022] This invention provides a construction method for gradient filling of non-combustible packing material and gas absorption in a capping layer of a gas well. This method constructs an in-situ gas treatment system that coordinates a central gas channel structure, an annular liquid seal structure, a bottom sediment transport structure, and an environmentally adaptable control structure. The method is based on replacing the solid-phase filling medium with the physical properties of fluids and utilizing part of the energy and heat of the landfill gas to construct a gas collection and purification facility that can operate stably for a long time under dynamic geological conditions. In application environments where the filling material experiences uneven settlement, gas wells using traditional solid packing material, due to their rigid structure, will form bypass gaps between the packing material when the well body undergoes slight deformation, posing a risk of untreated landfill gas leakage. To address this problem, this construction method begins by laying an inner pipe as the core gas channel along the central axis within a pre-designed gas well borehole. This inner pipe can... High-density polyethylene, a corrosion-resistant material, is used to provide a specific upward channel for landfill gas from the bottom of the well to the surface. Then, inert aggregate, with a particle size range of 50 to 80 millimeters, is filled into the annular cavity formed between the inner tube of the core gas duct and the well wall of the pilot well. This creates interconnected voids between the particles to accommodate liquid and provides structural support for the inner tube of the core gas duct and the well wall. After this, liquid, such as reclaimed water or leachate from the landfill leachate treatment system, is injected into the annular cavity until a continuous dynamic liquid seal ring with a preset height is formed within the annular cavity. This height is set such that the hydrostatic pressure generated is sufficient to resist the lateral seepage pressure of the landfill gas. When the well body shifts due to geological subsidence, the liquid level of the liquid seal ring remains horizontal, thus maintaining continuous sealing of the lateral gas leakage channel.

[0023] Before determining the bottom spacing d of the inverted drainage bell jar, a parameter calibration procedure for the well bottom self-cleaning function needs to be performed. This procedure begins with collecting and analyzing the physical properties of typical solid precipitates at the well bottom to obtain their maximum equivalent spherical particle size. With wet density in leachate Based on these two parameters, a minimum critical airlift velocity sufficient to overcome particle gravity and static friction is determined through fluid dynamics calculations or by referring to standard drag force diagrams. Then, the target flow rate of the project. A dimensionless engineering safety factor of 1.2 to 1.5 is set to be applied to this critical flow velocity. The result after that, that is Ultimately, during on-site commissioning, the cross-sectional area of ​​the annular gap was changed by adjusting the bottom spacing d. And based on gas volume flow rate Relationship with flow velocity This makes the actual flow velocity at the gap... Achieve and stabilize at the preset engineering target flow rate This completes the configuration of the self-cleaning structure. During the operation of the liquid-sealed ring to purify the landfill gas, the added reaction agents will react with the harmful components in the gas to generate solid deposits. The accumulation of these deposits at the bottom of the well will pose a risk of blockage at the inlet of the core gas passage. To suppress this risk, in the step of laying the inner pipe of the core gas passage, the lower end of the core gas passage is constructed as an inverted flow bell structure. The lower edge of the flow bell is kept at a preset distance from the bottom of the gas well hole. The calibration process of this distance is as follows: based on the gas generation rate under the target operating conditions, calculate and set a flow velocity that can generate local negative pressure when the gas passes through the gap. This negative pressure is sufficient to draw in the liquid-solid mixture at the bottom of the well and rise with the airflow. An engineering-feasible distance range is five to ten centimeters. This structure uses the kinetic energy of the rising airflow to continuously transport the deposits at the bottom of the well to the middle and upper part of the liquid-sealed ring, avoiding the formation of hard scale at the gas inlet, thereby maintaining the long-term unobstructed flow of the gas passage.

[0024] Meanwhile, to address the issue of the liquid in the upper layer of the liquid seal ring freezing and failing due to low winter temperatures in cold regions, this construction method also includes the installation of a heat pipe and the establishment of an anti-freezing control system based on ambient temperature. One end of the heat pipe is connected to the warm landfill gas area deep within the gas well, while the other end opens into the liquid surface area of ​​the dynamic liquid seal ring. The control logic is as follows: A temperature sensor installed on the surface monitors the ambient temperature. When this temperature is lower than a preset threshold but higher than the liquid freezing point (e.g., 2°C), the control system intermittently opens a valve installed on the heat pipe, thus introducing a small flow of landfill gas carrying heat from the landfill into the upper layer of the liquid seal ring. In the liquid layer, heat exchange maintains the temperature above freezing, and the liquid is shut off after a preset duration or temperature recovery during a single conduction. This step utilizes the landfill's own heat resources, allowing the liquid seal structure to maintain its function in low-temperature environments. Furthermore, to achieve cost control and efficiency management of the purification process, this method establishes a closed-loop control mechanism for liquid-phase reaction efficiency. This mechanism uses inlet and outlet gas sensors at the inlet and outlet ends of the core gas duct to measure the concentration of target pollutants, thus avoiding the challenge of direct chemical measurement in harsh liquid-phase environments. The control system uses real-time data on the inlet concentration... and export concentration According to the calculation rules 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.

[0025] 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.

[0026] This construction method also includes a step to handle transient pressure pulses. This involves filling the liquid surface of the dynamic liquid seal ring with an elastic porous medium layer composed of waste tire fragments, and installing an acoustic sensor at the upper end of the core airway inner tube. This acoustic sensor performs spectral analysis on the acoustic signal of the air column inside the tube to identify drift events in the fundamental frequency of the air column resonant cavity (Helmholtz resonant cavity) caused by the rise of a large-scale airlock, and outputs this as a warning signal. When a pressure pulse occurs, the pushed-up liquid rushes into the elastic porous medium layer. Its porous structure provides a buffer space for the liquid, and its elastic deformation absorbs the impact energy. To maintain stable system operation, a liquid level sensor and an automatic replenishment device can also be installed to replenish liquid when the liquid level falls below the safety lower limit. Finally, the upper end of the core airway inner tube is led out through the surface cover layer.

[0027] Example 1: In a completed mine goaf environment, the backfill material undergoes uneven settlement under its own weight and ground pressure. The original gas-carrying well, which used solid backfill, deformed due to geological stress, forming a connecting gap between the backfill and the well wall. Backfill gas leaks along this path. Simultaneously, changes in the leachate level cause partial submersion or drying of the backfill, reducing or eliminating its gas processing function. After applying the above construction method, the operating status of the gas-carrying well is as follows: First, in the annular space between the core gas channel pipe and the well wall... The permeate taken from the field area is injected into the cavity to form a continuous dynamic liquid seal ring. The liquid level of the liquid seal ring remains horizontal even when the well body is tilted, thus forming a continuous physical barrier to the lateral permeation channel of gas. All gas is guided to the lower inlet of the core gas channel inner tube. To treat hydrogen sulfide in the gas, a reaction agent is added to the dynamic liquid seal ring. After reacting with the target harmful gas (such as methane, hydrogen sulfide, etc.), the resulting ferrous sulfide solid deposit accumulates at the bottom of the gas well cavity under the action of gravity.

[0028] As ferrous sulfide deposits accumulate at the bottom of the well, the rising landfill gas, upon passing through the inverted flow bell structure at the lower end of the core gas duct, experiences increased gas velocity and creates a localized negative pressure in the gap between this structure and the well bottom. This negative pressure draws the liquid-solid mixture from the well bottom into the bell, where it is transported by the bubble flow to the upper middle part of the liquid seal ring. The transported particles then re-settle. This transport process maintains the unobstructed flow at the gas inlet and provides gas sensors located at the inlet and outlet of the core gas duct with gas for effective concentration comparison, enabling the assessment of instantaneous purification efficiency. The closed-loop control process can trigger the dosing device to replenish the reaction agent based on the real-time changes in hydrogen sulfide concentration. When the surface temperature drops below freezing during the cold season, the heat pipe in the system introduces a stream of landfill gas carrying temperature from deep within the well into the upper liquid layer of the dynamic liquid seal ring after its temperature control valve is triggered. The heat exchange keeps the temperature of the surface liquid above freezing, and the liquid seal function can continue under low temperature conditions. The gas well system thus operates stably in interaction with the dynamic environment of the landfill, and its internal material and energy scheduling replaces the need for external physical dredging and functional packing replacement.

[0029] Example 2: To verify the sealing effectiveness and purification control capability of the construction method of the present invention under simulated dynamic geological settlement and continuous pollutant load conditions, a physical model comparison test consisting of an experimental group and a control group was established. The test platform consisted of two identical cylindrical containers filled with compacted filling material. The experimental group container contained the gas well system of the present invention, while the control group container contained a gas well using traditional crushed stone filling material. Both containers were connected to gas injection pipelines at the bottom to introduce simulated landfill gas of known composition. The containers were placed on a programmable hydraulic platform to apply controllable differential displacement. During the test, a mixed gas containing methane and hydrogen sulfide was introduced into the bottom of both containers at a constant flow rate. An initial dose of iron salt reaction agent was pre-added to the dynamic liquid seal ring of the experimental group. A high-precision methane detector was installed at the top of the container to continuously monitor possible gas leakage. At the same time, outlet gas sensors were installed at the outlet ends of the two gas wells to monitor the hydrogen sulfide concentration in the exhaust gas. The sensor data of the experimental group was connected to a controller for executing closed-loop control logic, where the efficiency threshold was... The system is set to 95%, and the data sampling period is set to 60 seconds. This period is designed to balance the rapid response to changes in gas concentration with the load on the data processing system. This duration is also sufficient to capture the dynamic process of efficiency decline due to reagent consumption and efficiency recovery after a closed-loop dosing.

[0030] 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.

[0031] Example 3: This example combines Figures 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. Figure 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.

[0032] like Figure 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.

[0033] like Figure 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.

[0034] 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 Reach or exceed a target flow rate preset to generate the airlift effect. The value.

[0035] The calibration process for the acoustic recognition logic of transient gas pressure pulses is as follows: After the gas well system operates continuously at a stable gas flow rate for an initial period, the acoustic signal output by the acoustic sensor at the upper end of the core gas channel tube during this period is collected and recorded. Spectral analysis is then performed on this signal to extract the time-series data of the Helmholtz resonance fundamental frequency of the gas column within the tube. Subsequently, statistical analysis is performed on the baseline data of this fundamental frequency to calculate its mean value under stable operating conditions. with standard deviation The logic rules for triggering early warnings are embedded within the monitoring system. These rules are set so that when a base frequency is detected in real time... continuous Each sampling point meets the condition. At that time, the system determines that it has identified the acoustic characteristics corresponding to the transient air pressure pulse and outputs a warning signal; in a specific configuration, the coefficient Set to 3, coefficient Once set to 5, and these two calibrations are completed, the self-cleaning structure and risk warning logic of the gas well system are configured to adapt to the operating conditions of this specific site.

[0036] Example 5: In a landfill where the gas-guiding well system of this invention has been installed and is continuously operating, in order to cope with the seasonal changes in the site environment and the long-term evolution of the landfill gas composition, it is necessary to perform periodic on-site calibration of specific parameters in the system's automated control logic. This involves the antifreeze control duration of the dynamic liquid seal ring and the single-time reagent dosage in the closed-loop control of liquid phase reaction efficiency. To calibrate the single-time conduction duration of the antifreeze control, when the site enters the low-temperature season, when the temperature probe deployed in the upper liquid layer of the dynamic liquid seal ring detects that the liquid temperature has dropped to near the antifreeze trigger threshold of 2°C, a manual conduction of the heat pipe is initiated, allowing the landfill gas carrying the temperature to enter the upper liquid layer. At the same time, the time required for the liquid temperature to rise from 2°C to the target temperature of 4°C is recorded. Then, the measurement duration will be... The single conduction duration parameter for antifreeze regulation during this operating cycle is set in the control system.

[0037] To calibrate the single-dose dosage for closed-loop control, the instantaneous purification efficiency during system operation is considered. Below the efficiency threshold When an automatic dosing event is triggered, an initial test dose of known volume is injected into the dynamic liquid-sealed ring via the dosing device. The reaction agent; if the purification efficiency is high after this addition. Not within a preset recovery time Internal rebound to Therefore, when the next automatic dosing event is triggered, the dosage will be increased by a preset step size, and this process will be repeated until a dosage is determined. This dose can be triggered within Within a time period Restore to The above, and this dosage The standard reagent dosage parameters for this operating cycle are fixed in the control logic of the control system. After this set of periodic field calibration procedures is completed, the automated operating parameters of the gas well system are updated to respond to the current environmental conditions and pollutant load.

[0038] Example 6: Before deploying the gas-guided well system of the present invention at a specific site assessed to have high gas production potential and the risk of transient gas pressure pulses, a standardized pre-parameter optimization procedure needs to be executed to set its passive safety redundancy and core function maintenance operating parameters; this procedure first optimizes the thickness of the elastic porous media layer. The setup is designed to determine the minimum thickness while meeting safety redundancy requirements, and to obtain the liquid volume that can be displaced by the maximum credible transient pressure pulse based on the site assessment report. The effective porosity of waste tire debris media was determined. ;thickness The settings must meet the constraints. ,in, The total pore volume provided to the medium layer is the cross-sectional area of ​​the annular cavity of the gas well. thickness With effective porosity The product of As a safety factor, a value of 1.5 is used to calculate the factors that satisfy the constraint. The minimum value is used as a construction parameter.

[0039] The procedure then configures the automatic level replenishment logic for the dynamic liquid seal ring, including its lower limit level. The upper limit of the hydrostatic pressure height is set to generate a pressure that can withstand the maximum conventional lateral air pressure in the field area. It is set at a certain distance below the bottom of the elastic porous media layer to retain gas buffer space; to cope with abnormal conditions such as sensor failure or well leakage, a timeout interruption mechanism is set in this logic, with a maximum allowable continuous refueling time. The method for determining its value is as follows: first, based on the rated flow rate of the supply device and... and The volume between them is used to calculate the time required for normal resupply. Then Set as A multiple of, if the continuous operating time of the supply device exceeds The control system will then detect the anomaly, interrupt the supply, and issue a warning. After this procedure is completed, the passive safety parameters and automated maintenance logic of the gas well system for this specific site will be determined and loaded into its control system.

[0040] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

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 gradient filling of non-combustible packing material and gas absorption construction of a gas-guiding well 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 basic agents and iron salt agents.

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.

Images