CN114231322B - Gas purifying and carbon dioxide circulating treatment method - Google Patents

Abstract

The invention provides a gas purification and carbon dioxide cyclic treatment method, which comprises the following steps: determining the stratum depth and stratum inclination angle of a coal layer, drilling a gas injection well, a gas production well and a directional well, injecting gas into the directional well through the gas injection well, igniting a combustion cavity, and sequentially entering the gas into a heat exchanger and a cooling tower through the gas production well for heat exchange; then the mixture enters a desulfurization tower for desulfurization treatment to form sulfate solution, and part of carbon dioxide is absorbed simultaneously to form carbonate solution and sulfate mixed solution; the coal gas enters a decarbonization tower to convert carbon dioxide in the coal gas into alcohol amine solution rich solution; the alcohol amine solution rich solution is conveyed to a stripping tower, and the alcohol amine solution rich solution is decomposed by a catalyst in the stripping tower to produce carbon dioxide gas. The technical scheme of the application effectively solves the problem that the carbon dioxide in the coal gas in the related technology is directly discharged so as to increase the environmental pollution.

Description

Gas purifying and carbon dioxide circulating treatment method

Technical Field

The invention relates to the technical field of gas purification, in particular to a gas purification and carbon dioxide recycling treatment method.

Background

The principle of coal gasification refers to that in a specific environment, organic matters in coal and injected gasifying agents (oxygen/nitrogen/carbon dioxide gas, water vapor and the like) are combusted to generate high temperature under the condition of certain pressure and temperatureA series of chemical reaction processes for producing gas by decomposing with water vapor to convert solid coal into CO and H₂ 、CH₄ Etc. combustible gases and CO₂ And a process of non-combustible gas such as N2. When coal is gasified, three conditions, namely a gasifier, an oxidant and steam, are required to be provided. Reactions occurring in gasification processes include pyrolysis, gasification, and combustion reactions of coal. Pyrolysis of coal refers to the process of decomposing coal from a solid phase to a gas, solid, liquid three-phase product.

The coal gasification is divided into ground gasification and underground in-situ gasification, the ground gasification is carried out in a controllable gasification furnace produced in a manufacturing factory, coal is controlled by constant pressure gasification in the gasification furnace to obtain stable coal gas components, the coal gasification furnace is ideal coal gasification equipment, the underground gasification furnace is an original geological coal bed gasification furnace formed by drilling in a natural geological state, because the natural geological characteristic coal bed is influenced by extrusion of upper and lower strata and underground water immersion, pressure control in a gasification channel, leakage of external force immersed into the stratum under the action of stratum pressure and the action of coal gas pressure are in two aspects of positive pressure and back pressure, pressure change or unbalance can cause gasification state change, thereby influencing effective coal gas component change, and different stratum pressures of coal bed depths are different, the method is characterized in that the method comprises the steps of carrying out a control on the influence of multiple flow states of a coal bed on a gasification furnace chamber in underground coal gasification by using a unique technical method and special equipment, treating the underground coal gasification furnace as a controllable simulated ground gasification furnace so as to realize the regulation and control on the effective components of coal gas in the multiple flow states in the gasification of underground coal in situ, realizing the controllable combustion, controllable gasification, stable pressure and stable yield and pressure-maintaining gasification of the gasification furnace chamber under the conditions of high temperature and high pressure, wherein the high pressure is determined by the natural condition of the geological pressure of a stratum, the high pressure is one hand, the immersion of the stratum outside of the coal bed with high pressure is avoided, the high pressure ensures the rapid cooling of the mixed coal gas in the coal gasification furnace when the mixed coal gas flows out of the ground, thereby reducing the time of oxidizing carbon monoxide into carbon dioxide, but fine coal ash dust particles are mixed in the coal gas flow, and affecting the purity of the coal gas. And the gas contains a large amount of carbon dioxide, so that the carbon dioxide cannot be combusted, the combustion effect of the gas can be influenced, and meanwhile, if the carbon dioxide is discharged, the environmental pollution can be increased.

Disclosure of Invention

The invention mainly aims to provide a gas purification and carbon dioxide recycling treatment method, which aims to solve the problem that the carbon dioxide in the gas in the related technology is directly discharged so as to increase environmental pollution.

In order to achieve the above object, the present invention provides a gas purification and carbon dioxide recycling method, comprising: step S10: determining stratum depth and stratum inclination angle of a coal layer, drilling a gas injection well and a gas production well at the determined well position of the coal layer, and drilling a directional well in the coal layer so that the directional well is communicated with the gas injection well and the gas production well, forming an interactive well bottom at the joint of the directional well and the gas production well, and forming a combustion cavity at the rear end of the interactive well bottom; step S20: injecting gas into the directional well through the gas injection well to ignite the combustion chamber and generate gas; step S30: the gas sequentially enters a heat exchanger and a cooling tower through a gas production well to exchange heat; step S40: the gas subjected to heat exchange enters a desulfurizing tower for desulfurization treatment to form sulfate solution, part of carbon dioxide is absorbed simultaneously to form carbonate solution and sulfate mixed solution, and then the sulfate and carbonate mixed solution is buffered and injected into the ground; step S50: the gas after desulfurization treatment enters a decarbonization tower to convert carbon dioxide in the gas into alcohol amine solution rich solution; step S60: delivering the alcohol amine solution rich solution to a gas stripping tower, and decomposing the alcohol amine solution rich solution in the gas stripping tower through a catalyst to produce carbon dioxide gas; in step S60, the gas enters a heat exchanger and a cooling tower to exchange heat, and the heat is transferred to the stripping tower to heat the stripping tower, so that the stripping tower is kept at a constant temperature.

Further, step S70 is further included after step S60, step S70: the generated carbon dioxide gas is conveyed to a gas injection well through an RTP pipe and injected into a combustion chamber.

Further, step S70 is followed by step S80, step S80: the carbon dioxide gas is reduced into carbon monoxide and oxygen in the combustion chamber under the action of the nano alumina catalyst and high temperature.

Further, in step S50, the inside of the decarbonization tower includes a spiral spray pipe, the spray pipe is filled with an alcohol amine solution lean solution, and a carbonic anhydrase catalyst is spray-cured on the inner wall of the decarbonization tower and the outer wall of the spray pipe.

Further, in step S60, nano titanium oxide is added to the stripping column.

Further, in step S60, after decomposing the alcohol amine solution rich solution, an alcohol amine solution lean solution is generated, and the alcohol amine solution lean solution is transported to the decarbonizing tower by a pump.

Further, in step S60, the heat obtained by the heat exchange is partially subjected to waste heat power generation, and the remaining heat is transferred to the stripping tower.

Further, in step S40, limestone water is injected into the desulfurizing tower so that the limestone water performs desulfurization treatment on the gas.

Further, in step S30, the cooling tower can perform dust removal treatment on the gas.

Further, in step S30, the gas is rotated downward in the cooling tower by centrifugation, and moved upward at a conical structure contacting the bottom of the cooling tower, and solid dust particles in the gas are discharged through the bottom of the cooling tower.

By applying the technical scheme of the invention, the stratum depth and stratum inclination angle of the coal layer are firstly determined, the well position of the gas injection well and the well position of the gas production well are selected in the determined well position of the coal layer, and the well position of the gas injection well and the well position of the gas production well are positioned at two ends of the coal layer, so that the underground combustion chamber is large enough, and the gas production efficiency can be ensured. Drilling and completing after determining the well position of the gas injection well and the well position of the gas production well to obtain the gas injection well and the gas production well; and then drilling a directional well so as to communicate the directional well with the gas injection well and the gas production well, reaming the joint of the gas production well and the directional well to form an interactive well bottom, and pumping back for a certain length to form a combustion cavity so as to prepare for generating coal gas by igniting a coal bed later. Gas is injected into the combustion chamber through the gas injection well to ignite the combustion chamber to generate gas. The generated gas is high-temperature and high-pressure gas, and the gas is conveyed to a heat recovery cooling tower through a gas production well to perform heat exchange so as to reduce the temperature of the gas and effectively utilize the high temperature of the gas. The gas subjected to heat exchange needs to be subjected to desulfurization treatment, namely the gas is conveyed into a desulfurization tower for desulfurization treatment, so that the gas is relatively pure. However, the gas also contains a large amount of carbon dioxide, so that the carbon dioxide cannot be combusted and the emission can have a great influence on the environment. Thus, carbon dioxide needs to be recovered. The coal gas is conveyed into a decarbonizing tower, and carbon dioxide is converted into alcohol amine solution rich solution through a solvent absorption mode. At this time, the sulfate solution formed by desulfurization is conveyed to an underground filling buffer Chi Zancun, and the sulfate solution and other harmful wastes are mixed and pulped to be filled into an underground coal seam. And (3) conveying the alcohol amine solution rich solution formed by absorbing carbon dioxide by the solvent to a stripping tower for regeneration, and transferring heat obtained by heat exchange to the stripping tower under the action of a catalyst to heat and keep the temperature of the stripping tower so as to decompose and separate out carbon dioxide gas from the alcohol amine solution rich solution and reduce the alcohol amine solution lean solution. The carbon dioxide gas is recovered and then injected into the combustion chamber to be converted into carbon monoxide or used for other purposes, thereby realizing the zero emission of the carbon dioxide. Therefore, the technical scheme ensures that the problems of gas purification and direct carbon dioxide emission can increase environmental pollution, and realizes the energy mode of carbon dioxide capture, utilization and conversion. Therefore, the technical scheme effectively solves the problem that the carbon dioxide in the coal gas in the related technology is directly discharged so as to increase the environmental pollution.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. In the drawings:

FIG. 1 shows a schematic flow diagram of an embodiment of a gas purification and carbon dioxide recycle treatment process according to the present invention;

FIG. 2 shows a schematic diagram of the heat exchanger, cooling tower, desulfurizing tower, decarbonizing tower and stripping tower of the gas purification and carbon dioxide recycling process of FIG. 1;

FIG. 3 shows a partial enlarged view at A of FIG. 2;

FIG. 4 illustrates the gasification back-pumping combustion chamber formation process for coal seam, gas injection well, gas production well, and directional well of the gas cleaning and carbon dioxide recycling process of FIG. 1.

Wherein the above figures include the following reference numerals:

10. a coal layer; 20. a gas injection well; 30. a gas production well; 40. a directional well; 401. a first combustion chamber; 50. a combustion chamber; 60. a cooling tower; 70. a desulfurizing tower; 80. a carbon removal tower; 81. a shower pipe; 90. a stripping tower; 100. a heat exchanger.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description. Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate. In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.

The in-situ controllable combustion pressure-maintaining gasification of underground deep coal is characterized in that the state of underground coal seam gasification is simulated into a closed environment of a ground gasification furnace, underground deep coal is directly gasified in an original geological reservoir, a single well group gasification furnace is formed by a special designed gasification well group and special equipment matched with the special gasification well group, a continuous controllable gasification furnace chamber is formed by the combustion gasification of coal outside the toe nozzle through a special gas injection well 20 head device, a PLC controlled gas production pressure measurement and control well head device, a PLC controlled high-temperature high-pressure gas injection boiler, a PLC controlled high-pressure gas injection manifold and a PLC controlled special compound continuous gas injection pipe device, various oxidation catalysts required by gasification are injected into the coal layer, the tail end nozzle of the continuous pipe in the coal layer is the inlet of the high-temperature high-pressure oxidation catalyst, the back extraction length of the continuous pipe is the raw material coal of the gasification furnace, the injection nozzle of the oxidation catalyst moving like a moving toe, the coal outside the toe nozzle is gasified to form a continuous controllable gasification furnace chamber, the gas flow naturally flows to a low-pressure gas production port, and the gas flow is controlled by an electric control valve on the main path of the gas production measurement and control well head device, so that the underground coal seam can be gasified, the temperature of the coal layer can be controlled, the state of the gasification furnace can be changed, and the gasification state of the gasification furnace can be changed. The measurement port is arranged on the measurement and control gas wellhead device to perform online real-time data acquisition, detection, calculation, analysis, judgment and decision on the synthetic gas flow, so that the states of the gasification catalyst and related equipment at the gas injection side are regulated and controlled, and the underground deep coal seam gasification furnace chamber is subjected to controllable pressure, stable pressure and pressure maintaining gasification under a relatively stable pressure state, thereby ensuring the deep coal seam gasification furnace chamber to be in a stable pressure state Effective gas component H of synthetic gas parameters generated by layer coal gasification according to design requirements₂ +CO), maximizing gas heating value, maximizing gas flow rate and maximizing gas yield. And in order to realize H₂ +CO maximization, gas heating value maximization, gas flow yield maximization. The high-temperature and high-pressure gas produced by the gas production wellhead contains a large amount of high-temperature heat energy, fine dust, sulfur-containing gas and carbon dioxide components, and the gas must be purified for use in the subsequent process flow and separation and conversion of the gas.

As shown in fig. 1, 2 and 4, in the present embodiment, the gas purification and carbon dioxide recycling method includes: step S10: determining the stratum depth and stratum inclination angle of the coal layer 10, drilling a gas injection well 20 and a gas production well 30 at the determined well position of the coal layer 10, and drilling a directional well 40 in the coal layer 10 so that the directional well 40 is communicated with the gas injection well 20 and the gas production well 30, forming an interactive well bottom at the joint of the directional well 40 and the gas production well 30, and forming a combustion cavity 50 at the rear end of the interactive well bottom; step S20: injecting gas into the directional well 40 through the gas injection well 20 to ignite the combustion chamber 50 and produce gas; step S30: the gas sequentially enters the heat exchanger 100 and the cooling tower 60 through the gas production well 30 for heat exchange; step S40: the gas subjected to heat exchange enters a desulfurizing tower 70 for desulfurization treatment to form sulfate solution, part of carbon dioxide is absorbed simultaneously to form carbonate solution and sulfate mixed solution, and then the sulfate and carbonate mixed solution is buffered and injected into the ground; step S50: the gas after desulfurization treatment enters a decarbonization tower 80 to convert carbon dioxide in the gas into alcohol amine solution rich solution; step S60: delivering the alcohol amine solution rich solution to a stripping tower 90, and decomposing the alcohol amine solution rich solution in the stripping tower 90 through a catalyst to produce carbon dioxide gas; wherein, in step S60, the heat obtained by heat exchange of the gas entering the heat exchanger 100 and the cooling tower 60 is transferred to the stripper 90 to heat the stripper 90, so as to keep the stripper 90 at a constant temperature.

By applying the technical scheme of the embodiment, firstly, the stratum depth and stratum inclination angle of thecoal layer 10 are determined, the well position of the gas injection well 20 and the well position of the gas production well 30 are selected in the determined well position of thecoal layer 10, and the well position of the gas injection well 20 and the well position of the gas production well 30 are positioned at two ends of thecoal layer 10, so that the underground combustion chamber 50 is large enough, and the gas production efficiency can be ensured. Drilling and completing after determining the well locations of the gas injection well 20 and the gas production well 30 to obtain the gas injection well 20 and the gas production well 30; and then drilling thedirectional well 40 so as to enable thedirectional well 40 to be communicated with the gas injection well 20 and the gas production well 30, reaming the joint of the gas production well 30 and thedirectional well 40 to form an interactive well bottom, and pumping back for a certain length to form a combustion chamber 50 so as to prepare for subsequent ignition of coal seam to generate coal gas. Gas is injected into the combustion chamber 50 through a gas injection well to ignite the combustion chamber 50 to produce gas. The generated gas is high-temperature and high-pressure gas, and the gas is conveyed to the heatrecovery cooling tower 60 through the gas production well 30, and heat exchange is performed to reduce the temperature of the gas, and the high temperature of the gas is effectively utilized. The heat exchanged gas is required to be desulfurized, that is, the gas is transferred to the desulfurizingtower 70 to be desulfurized, so that the gas can be relatively pure. However, the gas also contains a large amount of carbon dioxide, so that the carbon dioxide cannot be combusted and the emission can have a great influence on the environment. Thus, carbon dioxide needs to be recovered. The gas is sent to a decarbonizingtower 80, and carbon dioxide is converted into alcohol amine solution rich liquid by means of solvent absorption. At this time, the sulfate solution formed by desulfurization is conveyed to an underground filling buffer Chi Zancun, and the sulfate solution and other harmful wastes are mixed and pulped to be filled into an underground coal seam. And (3) conveying the alcohol amine solution rich solution formed by absorbing carbon dioxide by the solvent to the strippingtower 90 for regeneration, and transferring heat obtained by heat exchange to the strippingtower 90 under the action of a catalyst to heat and keep the temperature of the strippingtower 90 constant, so that the alcohol amine solution rich solution is decomposed to separate out carbon dioxide gas and reduce the alcohol amine solution lean solution. The carbon dioxide gas is recovered and then injected into the combustion chamber 50 to be converted into carbon monoxide or used for other purposes, thereby realizing the zero emission of carbon dioxide. Therefore, the technical scheme ensures that the problems of gas purification and direct carbon dioxide emission can increase environmental pollution, and realizes the energy mode of carbon dioxide capture, utilization and conversion. Therefore, the technical scheme of the embodiment effectively solves the problem that the carbon dioxide in the coal gas in the related technology is directly discharged so as to increase the environmental pollution.

The alcohol amine solution rich solution is an alcohol amine solution containing a large amount of carbon dioxide, and the alcohol amine solution lean solution contains no carbon dioxide or a small amount of carbon dioxide. The alcohol amine solution is alcohol amine MDEA (Methyldiethanolamine) solution with molecular formula of C₅ H₁₃ NO₂ 。

In this embodiment, the method further includes the steps of: the sulfate solution is delivered to an underground infusion buffer Chi Zancun, and the sulfate solution is infused into the underground coal seam with other hazardous waste mixed slurrying treatments.

As shown in fig. 1, 2 and 4, in the technical solution of this embodiment, the cooling tower includes a plurality of two types connected in series, the desulfurizing tower includes a plurality of, the decarbonizing tower includes a plurality of, and the plurality of cooling towers are sequentially connected. The plurality of desulfurizing towers are communicated in sequence, and one desulfurizing tower positioned at the head end of the plurality of desulfurizing towers is communicated with one cooling tower positioned at the tail end of the plurality of cooling towers. The plurality of carbon removal towers are communicated in sequence, and one carbon removal tower positioned at the head end in the plurality of carbon removal towers is communicated with one desulfurizing tower positioned at the tail end in the plurality of desulfurizing towers. The cooling tower comprises a first shell, an inner cooling pipe, an outer cooling pipe and a first inlet and outlet device, wherein the first inlet and outlet device is arranged above the first shell, the inner cooling pipe is arranged inside the first shell, the outer cooling pipe is arranged outside the first shell, the first inlet and outlet device comprises a volute structure, an air inlet and an air outlet, the air inlet is arranged on the side part of the volute structure, and the air outlet is arranged at the top of the volute structure. Through the arrangement that the gas enters the volute structure through the gas inlet, the gas rotates in the volute structure, so that the gas moves downwards, namely is in direct contact with the inner cooling pipe, and further the gradual heating and the temperature rising of the gas to the heat recovery solution and the temperature lowering of the gas are realized. Meanwhile, the inner cooling pipe is communicated with the outer cooling pipe, so that the cooling efficiency of the coal gas is higher. Dust in the coal gas can be effectively removed through the cooling tower; while heat exchange is effectively performed through the inner and outer cooling pipes, so that the heat exchange obtains a large amount of heat, which can be subjected to subsequent other operations (e.g., power generation). The inner cooling pipe and the outer cooling pipe are of spiral coil structures, the inner cooling pipe is communicated with the outer cooling pipe, and the water inlet is positioned at the end part of the outer cooling pipe, which is close to the bottom of the first shell.

As shown in fig. 1, 2 and 4, in the present embodiment, thecoal bed 10 is a pulverized coal bed, and of course, may be aconventional coal bed 10. The method and the technical equipment are suitable for various deep coal fields with depth of 2000 meters and focus on unattended intelligent full-automatic gasification coal mining of an original reservoir of the underground deep coal with depth of 800-1500 meters. The resource reserves are in principle not less than 5 million tons. The main factors considered are factors such as coal seam physical properties, coal quality components, coal seam depth, stratum inclination angle, coal seam water content, coal seam geological pressure, upper and lower top and bottom plate geological lithology, two-dimensional/three-dimensional seismic data, fault fracture zones, underground water reservoir depth and the like, and the utilization rate of coal gasification resources is 75-85%. The underground deep coal gasification is preferably selected to be a single-layer coal seam thickness in a whole coal field not lower than 5 m, a coal seam stratum inclination angle is smaller than 15 ℃, a top plate and a bottom plate are stably buried in an underground deep coal original reservoir layer between 800 m and 1500 m, the geological pressure of the coal reservoir layer is not higher than 7MPa, gas injection (steam) wells, single-well group strip gasification belts with a measurement and control gas production well 30 well interval of 2000 m are arranged in parallel and side by side at intervals of 20 m to 25 m, single-well group gasification furnace groups (the heat radiation depths of the gasification at two sides are respectively 10 m to 12.5 m along the steam injection well central line, the coal seam gasification widths are different when the coal types are gasified, the single-well group gasification furnace groups are arranged in parallel side by side, so as to form a gas injection well 20 array, the gas production well 30 is arranged in an array, gas injection side equipment is arranged in an array, each gas production side measurement and control well head device is integrated into a three-well (3 in-1, 5 in-1, 8 in-well 1) special gas collection gas conveying pipeline is conveyed into a well head heat recovery device, the heat recovery device is also used for heating the heat recovery device of the heat recovery tower to reach the constant temperature, and the heat of the heat source of the heat recovery device is directly cooled by the heat recovery device, and the heat of the heat source of the heat source is used for the heat recovery device. The working surfaces among all the injection and production well groups are areas with possibility of sedimentation, and the gasification single well groups are arranged in parallel and side by side to ensure that once sedimentation occurs, the sedimentation of the connecting pieces can be caused due to the connecting piece operation, so that the ground is smooth, and the gas purification, gas separation, power generation device and water electrolysis hydrogen production device matched with the ground are beneficial to avoiding the sedimentation and sliding areas of the gasification working surfaces or possibly caused by geological factors.

As shown in fig. 1, 2 and 4, in the present embodiment, step S10 includes: drilling well to a first preset depth under the ground surface vertically on the ground, and then performing surface casing cementing to obtain a vertical well; drilling a well into the vertical well, deflecting at a second preset depth on the vertical well and the coal seam roof to form an arc-radius directional shaft deflecting section track, drilling to the junction of the coal seam floor and the lower rock stratum, and then cementing through a sleeve to form a curved well; a coiled tubing, a guiding tool and a drilling tool assembly are put into the vertical well; continuously and circularly injecting oil-based mud into the continuous oil pipe; drilling a coiled tubing, a guiding tool and a drilling tool assembly in a pulverized coal layer along a coal bed bottom plate through a curved well, and drilling a directional well parallel to the coal bed bottom plate on the coal bed bottom plate; loosening the guiding tool and the drilling tool assembly to form a nozzle at the end port of the continuous oil pipe; after the directional well is drilled, oil-based mud is pumped from the directional well through the coiled tubing. The gas injection well 20 includes a vertical well and a curved well having a vertical depth of 2000m or less; the length of the directional well is less than 2400m. The oil-based mud comprises mineral oil, polyacrylamide thickener, ammonium dodecyl benzene sulfonate, hydroxymethyl cellulose and acrylonitrile-styrene-butadiene copolymer, wherein the proportioning equivalent is as follows:mineral oil 100%, and polyacrylamide thickener 0.3kg/m³ Ammonium dodecylbenzenesulfonate 5kg/m³ Hydroxymethyl cellulose 0.3kg/m³ An acrylonitrile-styrene-butadiene copolymer of 0.5kg/m³ . Based on the scheme, drilling is firstly carried out on the ground until the drilling reaches the first preset depth of the surface casing, and then the surface casing is well cemented to obtain a vertical well. And then continuing to drill the next step, namely drilling a coal seam roof of the vertical well to a certain distance for directional deflecting, guiding the curved arc well to a target point on the coal seam floor in a directional manner, and then setting an oil well casing well to form a technical casing well. And (3) a coiled tubing and a downhole directional guiding drilling tool combination are put into the technical casing shaft, and a slurry pump is started when the downhole drilling tool combination reaches a coal bed target point, so that the drilling operation is converted into the coal bed directional large-displacement well coiled tubing drilling operation. The slurry pump injects coal bed oil-based slurry into the shaft through the continuous oil pipe and circulates continuously, the oil-based slurry plays a role in lubricating the drill bit and carrying rock debris, so that the drill bit is convenient to drill in and pump out, and meanwhile, the wall of the shaft of the coal bed can be supported, and collapse of the wall of the shaft in the shaft is prevented. The vertical well section adopts conventional drilling mud, the coal bed oil-based mud is adopted for continuous oil pipe drilling of the coal bed large displacement well section, the deflecting arc-shaped bending well section of the vertical well section and the coal bed inner directional large displacement well is middle radius directional deflecting, friction force between the deflecting well section and the coal bed causes friction locking in a continuous oil pipe coal bed well shaft at a certain large displacement depth, the oil-based mud improves well shaft lubrication, sand carrying, support collapse prevention and leakage prevention functions, after the coal bed directional well is drilled, a releasing tool releases a downhole drilling tool to be combined in the coal bed drilling well shaft, the oil-based mud in the directional well shaft is pumped out through the continuous oil pipe, after the oil-based mud is pumped out, part of the oil-based mud exists on the well wall of the directional well, and the oil-based mud can also play a certain fixing effect on the well wall of the directional well. Thus, the drilling of the powder coal seam can be effectively realized, and collapse can be avoided.

As shown in fig. 1, 2 and 4, in this embodiment, in step S20, a continuous gas injection pipeline is run into a bottom hole reaming interaction place of a gas production well through a gas injection wellhead, after slurry in a space where the bottom hole of the gas production well 30 and a gasification directional well 40 are alternately reamed is pumped out through the continuous gas injection pipeline, dry gas is injected into the gas injection well 20 through a gas injection boiler, the dry gas reaches a continuous gas injection pipeline nozzle, heats and sweeps a gasification shaft and heats a coal seam gasification channel, a temperature detection port on a wellhead device of the gas production well 30 detects a wellhead gas temperature change state in real time, when the wellhead temperature of the gas production well 30 rises to a certain set parameter, boiler gas injection is stopped briefly, temperature data in the gas production well 30 is acquired on a ground measurement and control wellhead device on the gas production well 30, when the temperature data is larger than a preset value, the dry gas injection into the gas injection well 20 is stopped, and a firing element is thrown into a combustion chamber 50 through the continuous oil pipe, and meanwhile, the gas injection boiler is started to inject dry gas and an oxidant, namely oxygen into the gas injection well 20. Meanwhile, an ignition ball throwing material is put into a release ball throwing cylinder in a continuous tube roller, the ignition ball throwing is an ignition deflagration rubber ball which is specially made by taking butane as a main material, a gas injection boiler is immediately started to be turned into a gas injection state by opening the release ball throwing device, the spherical ignition material is blown into an inner tube of a composite continuous tube and sprayed out from a nozzle of the continuous tube into a coal layer, meanwhile pure oxygen gas is injected into the coal layer and enters a gas injection manifold, high-temperature dry gas at 300 ℃ heats and deflagrates the spherical ignition material, meanwhile, the injected oxygen accelerates deflagration of surrounding coal so as to ignite coal in a coal layer gasification channel, a wellhead gas online detection instrument acquires gas component change in real time, and the injection quantity of the injected pure oxygen gas is accelerated to regulate the combustion state of the coal so as to achieve the continuous gas injection process condition of coal layer gasification.

As shown in fig. 1, 2 and 4, in the present embodiment, step S70 is further included after step S60, and step S70: the generated carbon dioxide gas is transported through the RTP tube into the gas injection well 20 and injected into the combustion chamber 50. By the above-described operation, carbon dioxide can be effectively utilized, and after carbon dioxide is injected into the combustion chamber 50, a reaction can occur in the combustion chamber 50.

Specifically, the combustion chamber includes a first chamber, a second chamber, and a third chamber, and the generated carbon dioxide gas is injected into the first chamber through the gas injection well 20, and sequentially enters the second chamber, the third chamber, and the like when the coiled tubing is withdrawn. Through the operation, the carbon dioxide can be effectively utilized, and after the carbon dioxide is injected into the first cavity, the reaction stability of the continuous combustion, controllable gasification and crutch pressure gasification processes of coal can be ensured in the continuous back suction process of the second cavity and the third cavity.

In an embodiment not shown, carbon dioxide may also be used to synthesize starch, synthetic fertilizers, in petroleum mining, injection of carbon dioxide flooding into oil wells to increase crude oil yield (EOR), and in foundry, metal smelting, biopharmaceutical and other industries.

Carbon dioxide gas is a very stable molecular structure, and it is difficult to adopt a conventional method to convert CO₂ As raw materials, the coal can be decomposed only under the action of specific high temperature and catalyst, and the underground coal gasification cavity is just CO₂ Conditions are created for decomposition, and wet CO reduced in the stripping regeneration tower₂ The gas is directly returned to the gas injection manifold at the side of the gas injection well 20 through a multi-layer composite continuous PE pipe (RTP), the CCU is applied to capture carbon dioxide, and the composite RTP pipe has the advantages of pressure resistance, corrosion resistance and convenient connection. The CO₂ CO with gas returned directly to the gas injection well 20 without drying₂ An access port, a branch pipeline input valve of gamma-nano alumina powder (which is a catalyst with strong activity) on a gas injection manifold is opened simultaneously, and a plurality of mixed catalysts and CO are mixed₂ The nano alumina powder is conveyed into the first combustion chamber, the second combustion chamber and the third combustion chamber … … of thedirectional well 40 in the coal seam in a summarizing way, so that the speed of converting carbon dioxide into carbon monoxide can be improved by 5-20 times in the gasification chamber, the carbon dioxide can also enter the gasification chamber to obviously improve the combustion heat and the heat stability under the temperature regulation effect, and the summarized multiple catalysts (mainly steam and O) are arranged in the combustion chamber 50₂ )，CO₂ CO under the action of the nano alumina powder which is injected concomitantly₂ Respectively reduce to CO+O₂ ，O₂ And is consumed by coal gasification to control O₂ The content of the gas in the outlet is undetectable or trace, thereby realizing H₂ Maximizing the total +CO content, catalytic function CO with the aid of nano-alumina powder₂ The conversion rate of CO conversion is improved by 40 percent, and the carbon conversion rate is improved. Controlling gasification intracavity injection O₂ Content of O is ensured₂ Fully depleted in combustion chamber 50, O in gas from gas recovery well 30₂ Content minimizationAlso prevents CO oxidation reaction and realizes CO in gas₂ The content is minimized. O injection₂ The quantity determines the temperature in the gasification cavity, O₂ High concentration and high gasification chamber temperature rise, CO₂ Increased ratio, CH₄ Content decrease CO content decrease, otherwise when O₂ As the content decreases, the temperature in the combustion chamber 50 decreases, CO₂ Reduced content of CH₄ The content is increased, so by measuring CO and CO in the gas₂ 、O₂ 、CH₄ The content of the catalyst can control the temperature of the gasification furnace chamber, thereby adjusting the reasonable gasification state.

As shown in fig. 1, 2 and 4, in the present embodiment, step S70 further includes step S80, step S80: the carbon dioxide gas reacts with the nano alumina catalyst in the combustion chamber 50 at high temperature to produce carbon monoxide and oxygen. The nano alumina catalyst can decompose carbon dioxide into carbon monoxide and oxygen, so that the conversion of the carbon dioxide is effectively realized, and the direct emission of the carbon dioxide is avoided.

In this example, two reactions are performed in the combustion chamber:

the coal and gasifying agent undergo primary pyrolysis and gasification reaction (heating-high temperature):

from the above-mentioned one-time reaction, an excessive amount of oxygen O can be seen₂ The injection will raise the temperature within the combustion chamber 50 while oxygen O₂ Also is a core catalyst for promoting the coal to be transformed and gasified, and the coal is gasified by oxygen O as gasifying agent₂ And water vapor H₂ The primary gasifying agent reacts with carbon by heating, decomposing and gasifying under the action of O, and the high-temperature field environment causes the gas component to be CO+H₂ +CO₂ +CH₄ Is the main reaction.

The secondary reaction (high temperature-medium low temperature) is carried out again on the coal reactant, coal and the primary reactant:

this process is also carbon dioxide CO₂ The high temperature conversion and reduction process to carbon monoxide CO is carried out, the deep coal in the combustion chamber 50 is acted by pure oxygen gasifying agent and auxiliary catalyst, the coal and the gasifying agent are subjected to multiple chain reactions, and the underground gasification process of the finally produced coal is as follows:

coal (high temperature, high pressure, gasifying agent, catalyst) →C+CH₄ +CO+CO₂ +H₂ +H₂ O；

The secondary reaction mainly occurs in the reduction zone of the gas flow due to a large amount of oxygen O₂ And water vapor H₂ O is injected, the gasification reaction is fashionable to have excessive injected oxygen and water vapor flow into the slag zone where coal is gasified, and at the moment, the excessive water vapor converts carbon monoxide CO into carbon dioxide CO under the action of the excessive oxygen₂ Thus, the gasification process is to control the gasification of coal to realize hydrogen H₂ The process of maximizing the sum of the carbon monoxide and CO controls the minimum carbon dioxide content in the gas and controls the synthesis of methane CH₄ In the minimized process, the online real-time detection of the gas at the production wellhead is to control oxygen O₂ And water vapor H₂ The trace or undetected O, because of the existence of the high temperature field of pure oxygen gasification, nitride does not appear in the gas, but methane is difficult to be remained, and the target of gas regulation becomes the main component H in the control gas₂ +CO+CO₂ Maximizing the trace or undetectable amounts of other components, in fact hydrogen and carbon monoxide (H₂ +CO) maximization such that CO₂ The content is as low as possible.

The useless compounds generated by the accompanying reaction of other chemical elements in the coal component in the gasification process are removed in the ground purification link, such as sulfide H₂ S，SO₂ Tar, etc.

As shown in fig. 1 to 4, in the present embodiment, in step S50, the inside of thedecarbonization tower 80 includes aspiral shower pipe 81, an alcohol amine solution lean solution is injected into theshower pipe 81, and a carbonic anhydrase catalyst is spray-cured on the inner wall of thedecarbonization tower 80 and the outer wall of theshower pipe 81. The operation can effectively convert the carbon dioxide in the coal gas into alcohol amine solution rich liquid, and the addition of the carbonic anhydrase catalyst can improve the carbon dioxide absorption speed and efficiency. The method is an important ring in the carbon capturing and gas stripping, namely the utilization flow, adopts 30% alcohol amine solution lean solution to absorb carbon dioxide in high-pressure coal gas, and the alcohol amine solution lean solution is recycled catalyst to purify the carbon dioxide in the coal gas in aspray pipe 81, so that the formed alcohol amine solution rich solution enters agas stripping tower 90 to be heated and decomposed into carbon dioxide, and the alcohol amine solution rich solution enters a heating heat source in the carbon dioxidegas stripping tower 90 to come from a heat recovery heat exchanger and a heat recovery dust removal cooler.

MDEA+CO₂ →MDEA－CO₂ Alcohol amine solution absorbs and releases CO₂

In this embodiment, as shown in fig. 1, 2 and 4, γ -nano titanium oxide is added to the strippingcolumn 90 in step S60. The nano titanium oxide can improve the speed and efficiency of decomposing the alcohol amine solution rich solution.

As shown in fig. 1, 2 and 4, in the present embodiment, in step S60, the alcohol amine solution rich solution is decomposed to generate an alcohol amine solution lean solution, and the alcohol amine solution lean solution is transported to thecarbon removal tower 80 by a pump.

As shown in fig. 1, 2 and 4, in the present embodiment, in step S60, most of the heat obtained by heat exchange is used for waste heat power generation for on-site use or electrolytic hydrogen production, and the remaining part of the heat is transferred to the circulating constant temperature heating heat exchanger at thestripper 90 to replace the conventional stripper circulating heating boiler. The operation can effectively improve the utilization of the waste heat and avoid the waste of energy sources. The recovered heat energy can be used for ORC power generation and stripping regeneration after carbon dioxide capture, so that the cost of carbon dioxide capture and reuse can be effectively reduced, and power supply is also required by application equipment and field illumination in the gas purification process, and particularly, huge power supply can be generated by high-temperature gas heat during operation of a plurality of gasification wells. In the operation of the device, in order to avoid the cooling of tar in the coal gas caused by the temperature reduction of the coal gas, a heat insulation layer is formed on the inner wall of the device and the spiral coil pipe by condensation, and when the coal gas purification system is used in series in multiple stages, the temperature of the coal gas at the outlet of the heat exchange cooling tower is controlled within the range of 80-110 ℃.

As shown in fig. 1, 2 and 4, in the present embodiment, in step S40, limestone water is injected into thedesulfurization tower 70 so that the limestone water performs desulfurization treatment on the gas. The limestone aqueous solution reacts with sulfur to generate sulfate-gypsum, part of carbon dioxide reacts with limestone water to form carbonate, and the limestone aqueous solution collides with coal gas dust and tar to realize the functions of desulfurization, dust removal and tar removal. The desulfurization compound, gas dust and tar are collided in rotation to form a raindrop-shaped mixture to be settled and discharged. Limestone water as a desulfurization solution also reacts to carbon dioxide, but does not affect the acid removal treatment function of the coal gas.

As shown in fig. 1, 2 and 4, in the present embodiment, thecooling tower 60 can perform dust removal treatment on the gas in step S30. Dust in the gas can be precipitated, so that the dust removal treatment of the gas is realized.

As shown in fig. 1, 2 and 4, in the present embodiment, in step S10, the gas is rotated downward in thecooling tower 60 by centrifugation, and moves upward at a tapered structure contacting the bottom of thecooling tower 60, and solid dust particles in the gas are discharged through the bottom of thecooling tower 60. The operation can ensure the dust removal effect of the coal gas.

The underground deep coal pressure-maintaining gasification technology adopts pure oxygen gasification, accelerates the combustion, gasification and reduction processes of coal in a medium deep coal bed by high-pressure pure oxygen gasification, increases gas injection cost but actually reduces unit coal gas production cost, so that the main component in high-pressure synthetic coal gas is H₂ 、CO、CO₂ 、H₂ S is mainly more than 98%, and other components form synthetic gas components by alkyl hydrocarbon. The book is provided withThe invention aims to carry out purification and removal treatment on acid gas in synthesized high-pressure gas generated in the in-situ pressure-maintaining gasification process of deep coal, namely, hydrogen sulfide gas in the gas is removed, carbon dioxide in the gas is removed, and simultaneously CO is absorbed₂ The alcohol amine solution rich solution is accelerated to thermally decompose and separate out regenerated carbon dioxide gas in the stripping device by the catalysis of gamma titanium oxide in the stripping device. The regenerated carbon dioxide gas is directly conveyed into an air injection manifold of an air injection wellhead in the form of wet carbon dioxide through a reinforced corrosion-resistant composite PE flexible continuous rubber pipe RTP without dehydration, and CO₂ The gas is conveyed into the underground coal seam gasification furnace chamber through the regulation and mixing of the gas injection manifold, and is reacted with oxygen in the high-temperature high-pressure gasification furnace to be decomposed into carbon monoxide by virtue of the catalysis of gamma-gasified aluminum, so that the carbon monoxide content in the gas is improved, and the capture and the utilization of carbon dioxide are realized.

As shown in fig. 1, 2 and 4, in this embodiment, the pressure in the combustion chamber needs to be controlled, and the primary and secondary electric control valves on the gas measurement and control wellhead device of the gas production well 30 can be controlled by adjusting the gas injection amount of the gas injection well 20 to ensure the pressure in the gasification combustion chamber 50, so that pressure-maintaining gasification is realized. And simultaneously, the efficiency of coal gasification can be further ensured due to the real-time control of the gas injection quantity, and the pressure in the combustion chamber 50 can be ensured to be kept relatively stable.

As shown in fig. 1, 2 and 4, in this embodiment, the technical solution of this embodiment further includes the following steps: step S90: collecting gas injection amount of the gas injection well 20 and collecting gas production data of the gas production well 30; step S100: and controlling the gas injection amount and the withdrawal amount of the continuous oil pipe according to the gas production data. The gas is injected into the combustion chamber 50 through the continuous oil pipe to ignite the combustion chamber 50, gas injection parameter data of the gas injection working state of the gas injection equipment is collected at the gas injection well 20, gas production data is collected at the gas production well 30, and the gas injection amount and the continuous oil pipe back-pumping amount are adjusted in real time according to the gas production data. The gas production data comprise gas physical parameters and chemical component parameters, the hydrogen content ratio maximum value is determined according to the hydrogen content ratio and the carbon monoxide content ratio, and the gas injection is carried out according to the hydrogen content ratio maximum value The amount is controlled, the main effective components needed in the gas are hydrogen and carbon monoxide, and the more important components in the carbon monoxide and the hydrogen are hydrogen. It is therefore necessary to ensure that the hydrogen content is at its maximum in the gas, so that the gas utilization is higher. In order to ensure that the hydrogen ratio can be maximized, the gas injection amount at the gas injection well 20 needs to be adjusted in real time to achieve the maximization of the hydrogen ratio. Of course, the gas injection amount can also be controlled according to the maximization of the common ratio of the hydrogen content and the carbon monoxide content. As described above, the gas injection well 20 is adjusted in the gas injection amount to maximize the ratio of the hydrogen and carbon monoxide contents. Thegas production well 30 is provided with a gas detection and analysis device, gas production data is obtained through the gas detection and analysis device, the gas injection well 20 is provided with a catalyst supply device and a gas injection boiler, and the controller controls the catalyst supply device and the gas injection boiler according to the gas production data. The gas detection and analysis device can detect the components and the duty ratio of the gas, so that the gas production data can be obtained in real time, and the accuracy and timeliness of the gas production data are ensured. The gas injection boiler injects gas into the combustion chamber 50, so that the injected gas is high-temperature gas, and the combustion chamber 50 is more convenient to ignite. The pressure in the combustion chamber 50 is controlled to be maintained between 7MPa and 15 MPa. The above pressure ranges are effective to ensure combustion in the combustion chamber 50. Specifically, in this example, the pressure was kept at 10MPa. The control of the air charge is based on a relatively stable range of pressures in the combustion chamber 50. The above means that the gasification pressure in the gasification furnace chamber is stable in fluctuation variation in the control range when the combustion chamber 50 is burned. Thus ensuring more sufficient combustion of coal. The acquisition of the gas production data is carried out every preset time, wherein the preset time is 5 seconds to 20 seconds. Because the underground coal gasification quantity injection parameters need to reach the nozzles of the continuous oil pipe through the pipeline of the long continuous oil pipe, and a series of continuous processes such as coal heating, coal burning, gasification, reduction and the like are also needed during coal gasification, the single-well group measurement and control computer has little meaning on the coal gas parameters by adopting a high sampling rate, so that the sampling rate is designed to sample according to the selectable and presettable intervals of 5 seconds, 10 seconds, 15 seconds or 20 seconds, and the stability of the gas production data can be ensured . And (3) carrying out data acquisition on multiple gas production to form a decision group within 180 seconds in one measurement and control cycle, analyzing the current decision group to obtain an analysis result, controlling the injection quantity of each gas injection parameter and the withdrawal quantity of the continuous oil pipe according to the analysis result, and stably keeping the gasification pressure to fluctuate within a control range through measurement and control on pressure and temperature. According to analysis of the decision set, control can be made more accurate. And comparing the current gas production data with the last gas production data, and if the comparison results are different, putting the gas production data into a decision group. The operation can enable the control to control the gas injection quantity more timely. The gas injection monitoring unit monitors and collects the gas injection amount of the gas injection well 20, the controller can remotely control on line through remote equipment, the gas output by thegas production well 30 is 350 ℃ high-temperature high-pressure gas, the 350 ℃ high-temperature gas passes through the multistage heat recovery heat exchanger device to realize waste heat power generation, and the controller, the gas injection monitoring unit, the gas production monitoring unit and the gas purification unit are powered. The high-temperature and high-pressure gas overflowed from the gas production well 30 head device carries a large amount of gas sensible heat energy and tiny particle dust, and the single well group gas component (H₂ :35％、CO:41％、CO₂ :22.5％、CH₄ :1％、O₂ :0.2％、H₂ O0.3%), calculated gas mass of about 0.9981Kg/Nm³ The specific heat of the gas is about 1.3797 KJ/(Nm)³ At the temperature of 15 ℃ at the inlet temperature and 150 ℃ at the outlet temperature of the wellhead gas entering the efficient heat recovery heat exchanger, and the yield of the wellhead gas is 15000-18000 Nm³ And/h, the sensible heat of the single-well group gas is 4138 MJ/h-4966 MJ/h, the sensible heat of the single-well group gas is equivalent to 1149 KWh-1379 KWh, the ORC high-temperature power generation efficiency is calculated according to 20%, the on-site power generation equipment self-power consumption is calculated by 10%, the sensible heat of the single-well group gasification unit gas is used for 206 KW-248 KW of ORC generated energy, and when the mixed heat recovery and purification treatment of the 5-well group gas are carried out, the ORC power generation power 1030 KW-1240 KW is enough to ensure the on-site power consumption supply of the 5 single-well group gasification well site ground gas purification treatment modules and the construction site. If 180 groups of well groups in a 5 hundred million ton coal resource block are designed to roll and develop, waste heat power generation is huge.

The high-temperature high-pressure gas at 350 ℃ at the wellhead is a multi-component mixed commodity gas, the gas is used for separating and preparing hydrogen, generating electricity or other coal chemical fields, the sensible heat of the gas can only be recovered indirectly and non-contact due to the fact that the components of the gas contain inflammable and explosive components such as hydrogen, carbon monoxide and the like, the sensible heat of the gas is far higher than geothermal heat or conventional low-temperature waste heat, the gas is excellent in continuous heat energy supply, and the wellhead gas is directly connected into a heat exchanger to recover the sensible heat in order to avoid the loss of the sensible heat of the gas in a ground pipeline and the exposed air. The gas carries a large amount of dust particles due to high-pressure flow, a special high-temperature high-pressure high-dust heat exchanger is needed to recover gas sensible heat, coal ash dust is not accumulated, a double-stage serial high-temperature high-pressure high-dust vortex shell-tube heat exchanger is used for absorbing gas sensible heat (waste heat), high-temperature heat conducting oil (high-temperature heat conducting oil at 350 ℃ or 400 ℃) is adopted for circularly absorbing gas sensible heat, the high-temperature heat conducting oil is controlled to continuously circularly absorb sensible heat pressure, the temperature difference between the heat conducting oil temperature entering and exiting the heat exchanger is kept constant at 30 ℃, the temperature of a heat conducting oil outlet is controlled to be stable at 240 ℃ to 250 ℃, the heat conducting oil flowing out of the vortex shell-tube heat exchanger is absorbed, the heat conducting oil flowing out of the vortex shell-tube heat exchanger is conveyed to be injected into an ORC evaporator to evaporate and gasify R245fa through one path, and the heat conducting oil flowing out of the evaporator is returned into a heat conducting oil buffer oil tank at a heat conducting oil inlet of the vortex shell heat exchanger through a circulating pump, and an ORC heat source is formed between the heat conducting oil and the evaporator. The heat conduction oil entering the evaporator continuously evaporates and circularly gasifies ORC organic working medium R245fa in the evaporator, the evaporated organic working medium R245fa enters an organic working medium double-screw expander (turbine) to push a generator to generate continuous power, ORC instant power generation electric energy can be used for a construction site, and each group of ORC power generation system can ensure that 5 single-well group gasification units share the power supply of a gas purification system. The surplus power can be used for charging the energy storage device. The other way of sensible heat conduction oil of absorbed gas enters a rich liquid heat exchanger of the carbon dioxide stripping regeneration tower to heat the alcohol amine solution to maintain the constant temperature of the solution in the stripping tower, replaces the conventional circulating and reheating boiler function of the stripping tower,

The substances injected into the gas injection well 20 include a catalyst that can effectively control the composition of the gas produced by gasification of coal.

In the description of the present invention, it should be understood that the azimuth or positional relationships indicated by the azimuth terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal", and "top, bottom", etc., are generally based on the azimuth or positional relationships shown in the drawings, merely to facilitate description of the present invention and simplify the description, and these azimuth terms do not indicate and imply that the apparatus or elements referred to must have a specific azimuth or be constructed and operated in a specific azimuth, and thus should not be construed as limiting the scope of protection of the present invention; the orientation word "inner and outer" refers to inner and outer relative to the contour of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "upper surface at … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial location relative to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the exemplary term "above … …" may include both orientations of "above … …" and "below … …". The device may also be positioned in other different ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

In addition, the terms "first", "second", etc. are used to define the components, and are only for convenience of distinguishing the corresponding components, and the terms have no special meaning unless otherwise stated, and therefore should not be construed as limiting the scope of the present invention.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (8)

1. A method for purifying gas and circularly treating carbon dioxide, which is characterized by comprising the following steps:

step S10: determining the stratum depth and stratum inclination angle of a coal stratum (10), drilling a gas injection well (20) and a gas production well (30) at the determined well position of the coal stratum (10), and drilling a directional well (40) in the coal stratum (10) so that the directional well (40) is communicated with the gas injection well (20) and the gas production well (30), wherein an interactive well bottom is formed at the joint of the directional well (40) and the gas production well (30), and a combustion cavity (50) is formed at the rear end of the interactive well bottom;

Step S20: injecting gas into the directional well (40) through a gas injection well (20) to ignite the combustion chamber (50) and produce gas;

step S30: the gas sequentially enters a heat exchanger (100) and a cooling tower (60) through the gas production well (30) for heat exchange;

step S40: the gas subjected to heat exchange enters a desulfurizing tower (70) for desulfurization treatment to form sulfate solution, part of carbon dioxide is absorbed simultaneously to form carbonate solution and sulfate mixed solution, and then the sulfate and carbonate mixed solution is buffered and injected into the ground;

step S50: the gas subjected to desulfurization treatment enters a decarbonization tower (80) to convert carbon dioxide in the gas into alcohol amine solution rich solution;

step S60: delivering the alcohol amine solution rich solution to a stripping tower (90), and decomposing the alcohol amine solution rich solution in the stripping tower (90) through a catalyst to produce carbon dioxide gas;

wherein in the step S60, the gas enters the heat exchanger (100) and the cooling tower (60) to exchange heat, and the heat obtained by heat exchange is transferred to the stripping tower (90) to heat the stripping tower (90) so as to keep the temperature of the stripping tower (90) constant;

Delivering the sulfate solution to an underground filling buffer Chi Zancun, mixing the sulfate solution and the carbonate mixed solution, slurrying the mixture, and filling the mixture into an underground coal seam;

step S90: collecting gas injection amount of the gas injection well (20) and collecting gas production data of the gas production well (30);

step S100: controlling the gas injection quantity and the extraction quantity of the continuous oil pipe according to the gas production data;

step S70 is also included after said step S60,

the step S70: conveying the generated carbon dioxide gas into the gas injection well (20) through an RTP pipe and injecting the carbon dioxide gas into a combustion cavity (50);

the main and secondary electric control valves on the gas measurement and control wellhead device of the gas production well (30) can ensure the pressure in the combustion cavity (50) by adjusting the gas injection quantity of the gas injection well (20), and the pressure in the combustion cavity (50) is controlled to be kept between 7MPa and 15 MPa;

the step S70 is followed by a step S80,

the step S80: the carbon dioxide gas is reduced to carbon monoxide and oxygen in the combustion chamber (50) by a nano alumina catalyst and under the action of high temperature.

2. The gas purification and carbon dioxide recycling method according to claim 1, characterized in that in step S50, the inside of the decarbonization tower (80) comprises a spiral spray pipe (81), an alcohol amine solution lean solution is injected into the spray pipe (81), and carbonic anhydrase catalyst is sprayed and solidified on the inner wall of the decarbonization tower (80) and the outer wall of the spray pipe (81).

3. The gas purification and carbon dioxide recycling process according to claim 1, characterized in that in step S60, nano titanium oxide is added to the stripping column (90).

4. The gas purification and carbon dioxide recycling method according to claim 1, characterized in that in step S60, an alcohol amine solution lean solution is generated after decomposing an alcohol amine solution rich solution, and the alcohol amine solution lean solution is transported to the carbon removal tower (80) by a pump.

5. The gas purification and carbon dioxide recycling method according to claim 1, wherein in step S60, the heat obtained by the heat exchange is partially subjected to waste heat power generation, and the remaining heat is transferred to a stripping tower (90).

6. The gas cleaning and carbon dioxide recycling method according to claim 1, characterized in that in step S40, limestone water is injected into the desulfurizing tower (70) so that the limestone water is subjected to desulfurization treatment of the gas.

7. The gas cleaning and carbon dioxide recycling method according to claim 1, characterized in that in step S30, the cooling tower (60) is capable of dust removal treatment of the gas.

8. The gas cleaning and carbon dioxide recycling process according to claim 1, characterized in that in step S30 the gas is rotated downwards in the cooling tower (60) by centrifugation, moving upwards at a conical structure contacting the bottom of the cooling tower (60), solid dust particles in the gas being discharged through the bottom of the cooling tower (60).

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