Low permeability and strong adsorption coal heat injection equipment

Abstract

The present invention relates to the field of gas extraction, and specifically to low-permeability, highly adsorbent coal heat injection equipment, including a heating box, a conveying pipe, a conveying pipe and a pressure relief extraction pipe, a heater is provided in the heating box, a water injection port and an exhaust port are provided on the heating box; the conveying pipe runs through the heating box, the conveying pipe is detachably connected to one end of the conveying pipe, the pressure relief extraction pipe is connected to the side wall of one end of the conveying pipe and is connected to the conveying pipe, a valve is provided on the pressure relief extraction pipe, a one-way valve plate is rotatably provided in the conveying pipe, and the one-way valve plate is located between the heating box and the pressure relief extraction pipe. When this technical solution is adopted, it is convenient to improve the extraction rate of coal seam gas.

Description

Technical Field

[0001] The invention relates to the field of gas extraction, and in particular to low-permeability and strong-adsorption coal body heat injection equipment. Background Art

[0002] Coal seam gas pre-extraction is one of the fundamental measures to solve coal mine gas accidents. The gas in the coal body is mainly in adsorbed and free states. The conversion of adsorbed gas into free gas is mainly controlled by two factors: coal reservoir pressure and temperature. At present, most coal mines in my country use the method of reducing coal reservoir pressure to pre-extract gas. Domestic and foreign technicians have carried out a series of research work on coal body heat injection gas control technology and have achieved a lot of research results.

[0003] Existing research results show that temperature is an important factor affecting the adsorption, desorption and seepage of coal seam gas. For example, Ma Dongmin et al. conducted coal seam gas adsorption and desorption tests under isothermal conditions, and analyzed that increasing the reservoir temperature can promote the coal seam gas desorption process, which is theoretically feasible and should be taken seriously in engineering; Liang Bing et al. established a mathematical model of gas flow under non-isothermal conditions based on the adsorption and desorption laws of gas and the mechanism of solid-flow coupling between coal and gas, and gave a method and procedure for numerical solution using finite elements; Wang Yibo et al. proved through experiments that the desorption rate of coal seam gas under low temperature conditions is slower than that under normal temperature and variable temperature conditions; Yi Jun et al. converted the sound field into heat energy to increase the temperature of the coal seam system, and realized the numerical simulation of the sound field promoting the desorption and diffusion of coal seam gas; He Manchao et al. physically simulated the adsorption under uniaxial stress-temperature The gas migration process was studied and it was concluded that temperature increase was one of the factors inducing the desorption of a large amount of adsorbed gas in the coal body; Peng Shoujian et al. conducted physical simulation experiments on gas extraction under different initial gas pressures and different ground stress levels and concluded that the changes in gas flow and temperature were well correlated, showing a rapid decrease in the early stage of extraction and a slow decrease in the later stage, and the temperature drop over time conformed to a logarithmic function relationship; Yang Xinle et al. established a heat-fluid-solid coupling model with pore fluid pressure, coal rock skeleton particle displacement, and absolute temperature as basic variables, revealing the intrinsic connection between coalbed methane seepage, stress, and heat transfer after heat injection in coal seams, indicating that the coalbed methane production increased significantly after heat injection, which is an effective way to increase the production of low-permeability coalbed methane.

[0004] The above research results have laid a theoretical foundation for coal seam heat injection to control gas, but they only remain at the theoretical and experimental simulation stage, and have not been transformed and promoted in coal mines. Moreover, in some domestic coal mines, the coal seam gas control effect still fails to meet the expected goals when conventional gas control measures are adopted. The main manifestations are: the gas extraction time for low-permeability and highly adsorbent coal bodies is long and the extraction efficiency is low. Summary of the invention

[0005] The purpose of the present invention is to provide a coal body heat injection device, which increases the temperature of the coal seam through the heat injection device, promotes the speed and flow of gas desorption, thereby achieving the purpose of improving the coal seam gas extraction rate and shortening the gas control time.

[0006] In order to achieve the above-mentioned purpose, the technical solution of the present invention provides low-permeability and highly adsorbent coal heat injection equipment, including a heating box, a conveying pipe, a conveying pipe and a pressure relief extraction pipe. A heater is provided in the heating box, and a water injection port and an exhaust port are provided on the heating box; the conveying pipe runs through the heating box, and the conveying pipe is detachably connected to one end of the conveying pipe. The pressure relief extraction pipe is connected to the side wall of one end of the conveying pipe and is connected to the conveying pipe. A valve is provided on the pressure relief extraction pipe, and a one-way valve plate is rotatably arranged in the conveying pipe, and the one-way valve plate is located between the heating box and the pressure relief extraction pipe.

[0007] The technical effect of this scheme is: after water is injected into the heating box through the water injection port, the water is heated by the heater, and after being heated to a predetermined temperature, gas is injected into the conveying pipe. In the process of the gas flowing through the conveying pipe in the heating box, the temperature of the hot water in the heating box is transmitted through the conveying pipe to heat the gas, and the heated gas is injected into the coal seam hole through the transmission pipe inserted into the coal seam hole, so that the adsorbed gas is converted into free gas, and then the heating box is stopped to continue heating and the gas injection is stopped, and then the valve on the pressure relief extraction pipe is opened, and the free gas in the coal seam hole is extracted to the ground through the exhaust equipment, thereby improving the extraction rate of coal seam gas and shortening the gas control time.

[0008] Furthermore, the bottom of the heating box is provided with rollers, and the top of the heating box is provided with lifting rings. The technical effect of this solution is that the heating box is easy to move and lift.

[0009] Furthermore, a heat preservation and insulation layer is provided inside the side wall of the heating box. The technical effect of this solution is: it is convenient to store heat and prevent electric shock.

[0010] Furthermore, one end of the delivery pipe includes a circular hole section and a square hole section, the square hole section is located between the circular hole sections, the pressure relief extraction pipe is connected to the square hole section, the one-way valve plate is rotatably arranged in the square hole section, and the square hole section is provided with a block that can contact the one-way valve plate. The technical effect of this solution is that the one-way valve plate is more convenient to install in the square hole section, and the one-way valve plate has better sealing performance after contacting the block, thereby preventing gas from entering the heating box.

[0011] Furthermore, the square hole section is provided with a groove, which is arranged opposite to the pressure relief extraction pipe, and a limiting mechanism is arranged in the groove, which includes a tension spring and a limiting plate, and the limiting plate is slidably arranged in the groove, and the limiting plate is connected to the bottom of the groove through the tension spring, and the limiting plate can be against the one-way valve plate. The technical effect of this scheme is that when a suction device such as a negative pressure pump is used to suck gas, the limiting plate moves under the action of negative pressure and is against the one-way valve plate, thereby preventing the one-way valve plate from opening under negative pressure and preventing gas from entering the heating box.

[0012] Furthermore, a booster block is provided on the transmission pipe, a slide groove, an arc groove and an annular groove are provided on the inner side wall of one end of the transmission pipe, a gasket is provided in the annular groove, the slide groove is connected to the arc groove, the side wall of the arc groove is inclined to provide a channel connected to the annular groove, a booster bar is slidably provided in the channel, the booster bar can contact with the booster block and the gasket, and a spring is provided between the booster bar and the side wall of the channel. The technical effect of this scheme is: in order to facilitate the operation in the coal mine and consider the limited operation space, the transmission pipe needs to be inserted into the coal seam hole before connecting the transmission pipe with one end of the transmission pipe. In order to improve the sealing of the connection, it is usually necessary to set a sealing ring on the transmission pipe, which makes the connection between the transmission pipe and the transmission pipe very laborious; after the improvement of this scheme, after the booster block on the transmission pipe is inserted into the slide groove along the axial direction of the transmission pipe, the transmission pipe is rotated, so that the booster block rotates along the arc groove and pushes the booster bar to move, and after the booster bar contacts with the gasket, the gasket shrinks inward and fits tightly with the transmission pipe, thereby achieving the purpose of facilitating the connection between the transmission pipe and the transmission pipe and improving the sealing of the connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of an embodiment of the present invention;

[0014] Figure 2 for Figure 1 A partial enlarged view of the middle A;

[0015] Figure 3 It is a three-dimensional schematic diagram of the conveying pipe and the transmission pipe;

[0016] Figure 4 for Figure 3 A partial enlarged view of point B in the middle;

[0017] Figure 5 This is a schematic diagram of the gasket after shrinking. DETAILED DESCRIPTION

[0018] The following is further described in detail through specific implementation methods:

[0019] The figure marks in the drawings of the specification include: heating box 1, conveying pipe 2, transmission pipe 3, pressure relief extraction pipe 4, heating pipe 5, water injection port 6, exhaust port 7, square hole section 8, block 9, one-way valve plate 10, limit plate 11, booster block 12, slide groove 13, arc groove 14, gasket 15, channel 16, booster strip 17.

[0020] Embodiment 1:

[0021] Embodiment 1 is basically as shown in the attached Figure 1 , 2 As shown: Figure 1The low-permeability and highly adsorbent coal heat injection equipment shown includes a heating box 1, a conveying pipe 2, a transmission pipe 3 and a pressure relief extraction pipe 4. Hanging rings are welded on the left and right sides of the top of the heating box 1, and rollers are installed on the lower surface of the bottom of the heating box 1. A heater is installed in the bottom of the heating box 1. The heater can be a U-shaped heating tube 5, and the heating tube 5 is connected to a power supply through a wire; a water injection port 6 and an exhaust port 7 are opened on the top of the heating box 1; a cavity is opened in the side wall of the heating box 1 (not shown in the figure), and a thermal insulation material, such as an asbestos layer, is placed in the cavity.

[0022] The conveying pipe 2 runs through the heating box 1, and the left end of the conveying pipe 3 is connected to the air outlet of the blower. Figure 1 The right end of the delivery pipe 2 is detachably connected to the delivery pipe 2. In this embodiment, the delivery pipe 3 is directly inserted into the delivery pipe 2 for connection. Figure 2 As shown, the right end of the delivery pipe 2 includes a circular hole section and a square hole section 8, that is, a circular hole and a square hole are opened inside the delivery pipe 2, and the square hole section 8 is located between the left and right circular hole sections.

[0023] The side walls of the pressure relief extraction pipe 4 and the square hole section 8 are welded and connected to the delivery pipe 2. A ball valve is installed on the pressure relief extraction pipe 4. In addition, a ball valve is also installed on the left end of the water injection pipe and the delivery pipe 2. A block 9 is welded to the inner wall of the square hole section 8. A one-way valve plate 10 is rotatably arranged at the block 9, that is, a pin is welded on the front and rear sides of the one-way valve plate 10, and the pin is rotatably connected to the front and rear side walls of the square hole. The left side of the one-way valve plate 10 contacts the block 9. The one-way valve plate 10 is located between the heating box 1 and the pressure relief extraction pipe 4. When injecting gas, the one-way valve plate 10 rotates counterclockwise under the action of the airflow. Of course, in order to facilitate the measurement of the temperature, pressure and flow of the water body, a pressure gauge can be installed at the left end of the delivery pipe 2, a thermometer can be installed on the top of the heating box 1, and a thermometer and a flowmeter can be installed at the right end of the delivery pipe 2.

[0024] The specific implementation process is as follows:

[0025] After water is injected into the heating box 1 through the water injection port 6, the water is heated through the heating pipe 5. After being heated to a predetermined temperature, gas is injected into the conveying pipe 2. In the process of the gas flowing through the conveying pipe 2 in the heating box 1, the temperature of the hot water in the heating box 1 is transmitted through the conveying pipe 2 to heat the gas. The heated gas is injected into the coal seam hole through the transmission pipe 3 inserted into the coal seam hole, so that the adsorbed gas is converted into free gas. Then the power is turned off to stop the heating box 1 from continuing to heat and stop the gas injection. After that, the ball valve on the pressure relief extraction pipe 4 is opened, and the free gas in the coal seam hole is pumped to the ground by a negative pressure pump.

[0026] Embodiment 2:

[0027] Based on the first embodiment, Figure 2As shown, a groove is opened in the square hole section 8 of the conveying pipe 2, and the groove is arranged opposite to the pressure relief extraction pipe 4. A limiting mechanism is arranged in the groove, and the limiting mechanism includes a tension spring and a limiting plate 11. The limiting plate 11 is slidably arranged in the groove, and the limiting plate 11 is connected to the bottom of the groove through the tension spring, that is, the lower end of the tension spring is welded to the bottom of the groove, and the upper end of the tension spring is welded to the lower surface of the limiting plate 11. When the negative pressure pump sucks gas, the limiting plate 11 slides upward under the action of negative pressure and resists against the one-way valve plate 10, thereby preventing the one-way valve plate 10 from rotating counterclockwise to open under negative pressure, thereby preventing the gas from entering the heating box 1.

[0028] Embodiment three:

[0029] On the basis of Example 1 or Example 2, Figure 3 As shown, the transmission pipe 3 is circumferentially welded with a plurality of booster blocks 12 (only two are shown in the figure), as shown in FIG. Figure 4 As shown, the inner side wall of the right end of the delivery pipe 2 is provided with an annular groove and a number of slide grooves 13 and arc grooves 14 matching the booster block 12. The annular groove is used to accommodate a gasket 15. Both ends of the gasket 15 are tightly attached to the side walls of the annular groove, and a distance is left between the outer wall of the gasket 15 and the bottom of the annular groove.

[0030] The slide groove 13 is connected to the arc groove 14, and the left side wall of the arc groove 14 is inclined to open a channel 16 connected to the annular groove, and the right side wall of the arc groove 14 is also opened with a channel 16. A booster bar 17 is slidably arranged in the channel 16, and the left end of the booster bar 17 is located in the annular groove, and the booster bar 17 can contact the gasket 15 during the downward movement; the right end of the booster bar 17 is located in the channel 16 on the right side wall of the arc groove 14, and the booster block 12 can contact the booster bar 17 when it rotates downward in the arc groove 14. A spring is provided between the booster bar 17 and the lower side wall of the channel 16, one end of the spring is welded to the lower side wall of the channel 16, and the other end of the spring is welded to the booster bar 17.

[0031] After the booster block 12 on the transmission tube 3 is inserted into the slide groove 13 along the axial direction of the transmission tube 2, the transmission tube 3 is rotated clockwise to make the booster block 12 rotate along the arc groove 14 and push the booster bar 17 to move. After the booster bar 17 contacts the gasket 15, the gasket 15 shrinks inward as shown in the figure. Figure 5 The state shown (the dotted line represents the original state) is in close contact with the transmission pipe 3, thereby achieving the purpose of facilitating the connection between the transmission pipe 3 and the delivery pipe 2 and improving the sealing of the connection.

[0032] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. Low permeability and strong adsorption coal body heat injection equipment, characterized by: It comprises a heating box, a conveying pipe, a conveying pipe and a pressure relief extraction pipe. A heater is arranged in the heating box, and the heater is a U-shaped heating pipe. A water injection port and an exhaust port are arranged on the heating box. The conveying pipe runs through the heating box, and the conveying pipe is detachably connected to one end of the conveying pipe. The pressure relief extraction pipe is connected to the side wall of one end of the conveying pipe and is communicated with the conveying pipe. A valve is arranged on the pressure relief extraction pipe. A one-way valve plate is rotatably arranged in the conveying pipe, and the one-way valve plate is located between the heating box and the pressure relief extraction pipe. Rollers are arranged at the bottom of the heating box, and a lifting ring is arranged at the top of the heating box. A thermal insulation layer is arranged in the side wall of the heating box. One end of the conveying pipe comprises a circular hole section and a square hole section, and the square hole section is located between the circular hole sections. The pressure relief extraction pipe is communicated with the square hole section, and the one-way valve plate is rotatably arranged in the square hole section, and the square hole section is provided with a block capable of contacting the one-way valve plate. The square hole section is provided with a groove, and the groove is arranged relative to the pressure relief extraction pipe. A limiting mechanism is provided in the groove, and the limiting mechanism includes a tension spring and a limiting plate. The limiting plate is slidably arranged in the groove, and the limiting plate is connected to the bottom of the groove through the tension spring, and the limiting plate can resist the one-way valve plate; a booster block is provided on the transmission pipe, and a sliding groove, an arc groove and an annular groove are provided on the inner side wall of one end of the transmission pipe, a gasket is provided in the annular groove, the sliding groove and the arc groove are connected, and the side wall of the arc groove is inclined to be provided with a channel connected to the annular groove, and a booster strip is slidably arranged in the channel, and the booster strip can contact with the booster block and the gasket, and a spring is provided between the booster strip and the side wall of the channel; after the booster block on the transmission pipe is inserted into the sliding groove along the axial direction of the transmission pipe, the transmission pipe is rotated clockwise, so that the booster block rotates along the arc groove and pushes the booster strip to move, and after the booster strip contacts with the gasket, the gasket shrinks inward and fits tightly against the transmission pipe, thereby facilitating the connection between the transmission pipe and the transmission pipe and improving the connection sealing.

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