A cooling structure

Abstract

The application belongs to the technical field of petroleum and relates to a cooling structure, which comprises an inlet pipe, an inlet shrinkage pipe, a first throttling pipe, a second throttling pipe, a third throttling pipe, a fourth throttling pipe, a fifth throttling pipe, a sixth throttling pipe, a seventh throttling pipe, an outlet expansion pipe and an outlet pipe which are sequentially connected and communicated, the aperture of the inlet shrinkage pipe gradually decreases, the aperture of the outlet of the inlet shrinkage pipe is the same as the aperture of the first throttling pipe, the flow channel of the second throttling pipe is bent according to a preset direction to form a first preset angle with the flow channel of the first throttling pipe, the flow directions of the first throttling pipe, the third throttling pipe, the fifth throttling pipe and the seventh throttling pipe are the same, the flow channel of the fourth throttling pipe is bent according to a preset direction to form a second preset angle with the flow channel of the third throttling pipe, the sixth throttling pipe is bent according to a preset direction to form a third preset angle with the flow channel of the fifth throttling pipe, and the flow channel of the outlet expansion pipe gradually increases until the aperture is the same as that of the outlet pipe. The pipeline throttling and cooling are realized by the device itself, and the cooling effect is improved.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical technology, and specifically relates to a cooling structure. Background Technology

[0002] Underground coal gasification (UCG) refers to the controlled in-situ combustion of underground coal using appropriate technologies to produce combustible gases such as methane, hydrogen, and carbon monoxide. UCG is a clean coal development and utilization technology integrating well construction, coal mining, and gasification. By transforming physical coal mining into chemical gasification underground, it effectively avoids the safety and environmental problems caused by traditional coal mining methods and significantly improves resource utilization efficiency. Compared with surface coal-to-natural gas, underground coal gasification has significant advantages such as shorter process, higher safety, environmental friendliness, and better investment economics. However, because the coal undergoes a series of processing steps to transform into combustible syngas, the gasification equipment operates in a high-temperature and high-pressure environment, which can affect the service life of the extraction tubing and mining efficiency. Currently, underground temperature reduction methods include: one is to carry the temperature back to the surface through circulation, but the ultra-high temperature environment of 800℃-1000℃ near the underground combustion furnace in coal gasification mines has poor cooling effects. Furthermore, water molecules generated downhole can cause high-temperature corrosion to the tubing, affecting its lifespan. Secondly, special high-temperature resistant materials can be used downhole to extend the service life under ultra-high temperatures, but this is costly. Thirdly, a multi-layered production well structure can be used to inject low-temperature inert gas, using the mixed gas for heat exchange and cooling, but separating the subsequent mixed gas is difficult.

[0003] In summary, introducing other media to address the temperature drop problem in underground ultra-high-temperature processes has certain limitations. A new technology is needed to solve this problem. Furthermore, the high-temperature gases produced by in-situ shale oil gasification also face similar issues. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a cooling structure, comprising: an inlet pipe, an inlet constriction pipe, a first throttling pipe, a second throttling pipe, a third throttling pipe, a fourth throttling pipe, a fifth throttling pipe, a sixth throttling pipe, a seventh throttling pipe, an outlet expansion pipe, and an outlet pipe, connected sequentially and in communication. The diameter of the inlet constriction pipe gradually decreases, and its outlet diameter is the same as that of the first throttling pipe. The flow channel of the second throttling pipe is bent in a preset direction to form a first preset angle with the flow channel of the first throttling pipe. The flow directions of the first, third, fifth, and seventh throttling pipes are the same. The flow channel of the fourth throttling pipe is bent in a preset direction to form a second preset angle with the flow channel of the third throttling pipe. The flow channel of the sixth throttling pipe is bent in a preset direction to form a third preset angle with the flow channel of the fifth throttling pipe. The flow channel of the outlet expansion pipe gradually increases until it is the same as the diameter of the outlet pipe.

[0005] Optionally, the angle formed by the gradually narrowing flow channel of the inlet constriction tube is between 18° and 22°.

[0006] Optionally, the first preset angle, the second preset angle, and the third preset angle are all the same size, ranging from 43° to 47°.

[0007] Optionally, the flow channel diameter of the first throttling tube, the second throttling tube, the third throttling tube, the fourth throttling tube, the fifth throttling tube, the sixth throttling tube, and the seventh throttling tube is 20-40 mm.

[0008] Optionally, the angle formed by the gradually expanding flow channel of the outlet expansion tube is between 12° and 17°.

[0009] Optionally, the inlet pipe and the outlet pipe have the same flow channel diameter, both ranging from 80 to 120 mm.

[0010] Optionally, the first throttling tube and the seventh throttling tube have the same length, both between 80 and 150 mm.

[0011] Optionally, the third throttling tube and the fifth throttling tube are of the same length, both between 200 and 300 mm.

[0012] Optionally, the inlet pipe and the outlet pipe are parallel to each other and have the same length.

[0013] Optionally, the lengths of the inlet pipe and the outlet pipe are 200-400 mm.

[0014] The cooling structure of this invention achieves an initial pressure reduction in the gas pressure flowing through the inlet constriction tube to the first throttling tube by gradually reducing the diameter of the inlet constriction tube and ensuring that the outlet diameter is the same as that of the first throttling tube. This results in a corresponding temperature reduction within the pipe. Since each connection point of the first, second, third, fourth, fifth, sixth, and seventh throttling tubes and the outlet expansion tube has a preset angle bend, the gas pressure flowing through each bend is further reduced, further lowering the temperature within the pipe. By utilizing the change in the physical state of the airflow, the downhole pipe is throttled and cooled, thereby improving the cooling effect and avoiding heat exchange cooling through the mixed gas.

[0015] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the cooling structure in an embodiment of the present invention is shown.

[0018] In the diagram, 1 is the inlet pipe; 2 is the inlet constriction pipe; 3 is the first throttling pipe; 4 is the second throttling pipe; 5 is the third throttling pipe; 6 is the fourth throttling pipe; 7 is the fifth throttling pipe; 8 is the sixth throttling pipe; 9 is the seventh throttling pipe; 10 is the outlet expansion pipe; and 11 is the outlet pipe. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] To address the problems existing in the prior art, this invention provides a cooling structure for the ultra-high temperature gas generated during shale oil in-situ gasification or coal gasification. This cooling structure can achieve localized cooling by throttling the high temperature gas generated during shale oil in-situ gasification or underground coal gasification through small orifices, resulting in pressure and temperature drops. By rationally arranging the orifice position, number, and size of each throttling tube, a self-cooling effect is achieved, thereby solving the aforementioned problems.

[0021] like Figure 1 As shown, the present invention provides a cooling structure, comprising: an inlet pipe 1, an inlet constriction pipe 2, a first throttling pipe 3, a second throttling pipe 4, a third throttling pipe 5, a fourth throttling pipe 6, a fifth throttling pipe 7, a sixth throttling pipe 8, a seventh throttling pipe 9, an outlet expansion pipe 10, and an outlet pipe 11, which are connected and communicated in sequence. The orifice diameter of the inlet constriction pipe 2 gradually decreases, and its outlet orifice diameter is the same as that of the first throttling pipe 3. Specifically, the orifice diameter of the inlet constriction pipe 2 gradually decreases from its top end to its bottom end. The flow channel of the second throttling pipe 4 follows a preset direction. The bends form a first preset angle with the flow channel of the first throttling pipe 3. The flow directions of the first throttling pipe 3, third throttling pipe 5, fifth throttling pipe 7, and seventh throttling pipe 9 are the same. The flow channel of the fourth throttling pipe 6 bends in a preset direction to form a second preset angle with the flow channel of the third throttling pipe 5. The sixth throttling pipe 8 bends in a preset direction to form a third preset angle with the flow channel of the fifth throttling pipe 7. The flow channel of the outlet expanding pipe 10 gradually increases until it is the same as the orifice diameter of the outlet pipe 11. Specifically, the flow channel of the outlet expanding pipe 10 gradually increases from its top to its bottom. Due to the gradually decreasing orifice diameter of the inlet constricting pipe 2 and the preset angle bends at each pipe connection, the gas pressure flowing through the inlet constricting pipe 2 and each pipe bend decreases, resulting in a decrease in the temperature inside the pipe. This utilizes the change in the physical state of the airflow to achieve throttling and cooling of the downhole pipeline, thereby improving the cooling effect and avoiding heat exchange cooling through the mixed gas. Furthermore, the entire structure has the advantages of simple operation, low time consumption, and high efficiency. It should be noted that the flow channel of the outlet expansion pipe 10 gradually increases, making gas discharge easier. Furthermore, this invention primarily achieves a reduction in pipeline pressure and temperature based on this structure and the law of conservation of energy during gas state changes. Connection methods between the various pipes include, but are not limited to, threaded connections, bolted connections, riveted connections, and welding.

[0022] In one embodiment, the angle formed by the gradually narrowing flow channel of the inlet constriction tube 2 is between 18° and 22°. Optionally, the angle formed by the gradually narrowing flow channel of the inlet constriction tube 2 in this invention is 21°. Alternatively, the flow channel structure of the inlet constriction tube 2 can be regarded as conical. As the gas passes through the inlet constriction tube 2, the pressure inside the inlet constriction tube 2 gradually decreases, thereby reducing the temperature inside the tube.

[0023] In one embodiment, the first, second, and third preset angles are all the same size, ranging from 43° to 47°. Optionally, each preset angle in this invention is 45°. If the angle exceeds 47°, the connection points of the first throttling tube 3, second throttling tube 4, third throttling tube 5, fourth throttling tube 6, fifth throttling tube 7, sixth throttling tube 8, and seventh throttling tube 9 will experience significant pressure impact. If the angle is below 43°, the gas pressure impact on the pipes is insufficient, resulting in a smaller reduction in pipe pressure and a smaller corresponding temperature reduction, leading to a poor cooling effect.

[0024] In one embodiment, the orifice diameters of the first throttling pipe 3, the second throttling pipe 4, the third throttling pipe 5, the fourth throttling pipe 6, the fifth throttling pipe 7, the sixth throttling pipe 8, and the seventh throttling pipe 9 are all 20-40 mm. Optionally, the orifice diameters of the first throttling pipe 3, the second throttling pipe 4, the third throttling pipe 5, the fourth throttling pipe 6, the fifth throttling pipe 7, the sixth throttling pipe 8, and the seventh throttling pipe 9 are 20 mm. It should be noted that if the orifice diameter of each throttling pipe is too large, the force of the gas impacting the pipe wall after passing through each throttling pipe is insufficient, resulting in a smaller pressure loss and a smaller pressure reduction within the pipe, leading to a poorer cooling effect. If the orifice diameter is less than 20 mm, the pipe flow rate is small, the output gas volume is small, and the production output is low, failing to meet the minimum production requirements.

[0025] In one embodiment, the angle formed by the gradually expanding flow channel of the outlet orifice pipe 10 is between 12° and 17°. Optionally, the angle formed by the gradually expanding flow channel of the outlet orifice pipe 10 is 15°. Specifically, the flow channel structure of the outlet orifice pipe 10 can be regarded as a conical structure, which facilitates the discharge of gas into the outlet pipe 11.

[0026] In one embodiment, the flow channel orifice diameters of inlet pipe 1 and outlet pipe 11 are the same and both range from 80 to 120 mm. Optionally, the flow channel orifice diameters of inlet pipe 1 and outlet pipe 11 are 95 mm. The flow channel orifice diameters of inlet pipe 1 and outlet pipe 11 are within the range of 80-120 mm, thus facilitating gas entry and exit. If the flow channel orifice diameters of inlet pipe 1 and outlet pipe 11 exceed 120 mm, corresponding pipe lengths and inner diameters need to be designed. Even if connected to the pipes in this invention, due to the arrangement of intermediate pipe connections and orifice diameter settings, there will be no unexpected effects. Moreover, due to the larger inflow rate, the internal pressure of the pipe increases, which may prevent the cooling effect. Similarly, if the diameter is below 80 mm, the gas flow rate entering inlet pipe 1 will decrease, resulting in a lower subsequent gas discharge volume and lower gas delivery efficiency.

[0027] In one embodiment, the first throttling tube 3 and the seventh throttling tube 9 have the same length, both between 80 and 150 mm. Optionally, the length of the first throttling tube 3 and the seventh throttling tube 9 is 80 mm. It should be noted that the lengths of the first throttling tube 3 and the seventh throttling tube 9 can also be designed according to actual conditions, and the lengths of the first throttling tube 3 and the seventh throttling tube 9 can be greater than 150 mm or less than 80 mm.

[0028] In one embodiment, the third throttling tube 5 and the fifth throttling tube 7 are both of the same length, ranging from 200 to 300 mm. Optionally, the lengths of the third throttling tube 5 and the fifth throttling tube 7 are 200 mm. Optionally, the lengths of the third throttling tube 5 and the fifth throttling tube 7 are 80 mm. It should be noted that the lengths of the third throttling tube 5 and the fifth throttling tube 7 can also be designed according to actual conditions, and the lengths of the third throttling tube 5 and the fifth throttling tube 7 can be greater than 300 mm or less than 200 mm.

[0029] In one embodiment, the inlet pipe 1 and the outlet pipe 11 are parallel to each other and have the same length. Specifically, the lengths of the inlet pipe 1 and the outlet pipe 11 are 200-400 mm. Optionally, the lengths of the inlet pipe 1 and the outlet pipe 11 are 200 mm. It should be noted that the lengths of the inlet pipe 1 and the outlet pipe 11 can also be designed according to actual conditions.

[0030] In summary, this invention addresses the pressure and temperature drops generated by the ultra-high temperature gas before and after the orifice diameters of various pipes. By appropriately arranging the pipes, extraction efficiency issues caused by mismatched intake pressures applied to the injection well can be effectively avoided. Furthermore, by optimizing parameters such as the bending angles at pipe connections and the orifice diameters of the flow channels, optimal temperature drop effects can be achieved.

[0031] Based on the inherent physical properties of ultra-high temperature gases, the process parameters of each pipeline layout, and the pressure drop and temperature drop characteristics of the throttling orifice, this invention avoids the use of complex devices for physical cooling with water vapor or other chemical cooling methods. By combining petroleum gas or crude coal gas with downhole tools, the cooling objective is achieved, greatly simplifying the processes and complex equipment required for shale gas in-situ gasification and underground coal gasification. Furthermore, this invention effectively avoids the extraction efficiency problems caused by the ultra-high temperature environment underground in shale gas in-situ gasification and coal gasification. Moreover, it utilizes changes in the physical state of the gas flow to achieve downhole throttling and cooling, thereby achieving downhole throttling and cooling through changes in the gas state equation and the throttling effect. The entire tool also boasts advantages such as simple operation, low time consumption, and high efficiency.

[0032] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cooling structure, characterized in that, include: The following components are connected in sequence: inlet pipe (1), inlet constriction pipe (2), first throttling pipe (3), second throttling pipe (4), third throttling pipe (5), fourth throttling pipe (6), fifth throttling pipe (7), sixth throttling pipe (8), seventh throttling pipe (9), outlet expansion pipe (10), and outlet pipe (11). The diameter of the inlet constriction pipe (2) gradually decreases, and its outlet diameter is the same as that of the first throttling pipe (3). The flow channel of the second throttling pipe (4) is bent in a preset direction to connect with the first throttling pipe (3). The flow channels form a first preset angle, and the flow directions of the first throttling tube (3), the third throttling tube (5), the fifth throttling tube (7), and the seventh throttling tube (9) are the same. The flow channel of the fourth throttling tube (6) is bent in a preset direction to form a second preset angle with the flow channel of the third throttling tube (5). The flow channel of the sixth throttling tube (8) is bent in a preset direction to form a third preset angle with the flow channel of the fifth throttling tube (7). The flow channel of the outlet expansion tube (10) gradually increases until it is the same as the orifice diameter of the outlet tube (11).

2. The cooling structure according to claim 1, characterized in that, The angle formed by the gradually narrowing flow channel of the inlet constriction tube (2) is between 18° and 22°.

3. The cooling structure according to claim 1, characterized in that, The first preset angle, the second preset angle, and the third preset angle are all the same size, ranging from 43° to 47°.

4. The cooling structure according to claim 1, characterized in that, The flow channel diameters of the first throttling tube (3), the second throttling tube (4), the third throttling tube (5), the fourth throttling tube (6), the fifth throttling tube (7), the sixth throttling tube (8), and the seventh throttling tube (9) are all 20-40 mm.

5. The cooling structure according to claim 1, characterized in that, The angle formed by the gradually expanding flow channel of the outlet expansion tube (10) is between 12° and 17°.

6. The cooling structure according to claim 1, characterized in that, The inlet pipe (1) and the outlet pipe (11) have the same flow channel diameter, both ranging from 80 to 120 mm.

7. The cooling structure according to claim 1, characterized in that, The first throttling tube (3) and the seventh throttling tube (9) have the same length, both between 80 and 150 mm.

8. The cooling structure according to claim 1, characterized in that, The third throttling tube (5) and the fifth throttling tube (7) are the same length, both between 200 and 300 mm.

9. The cooling structure according to claim 1, characterized in that, The inlet pipe (1) and the outlet pipe (11) are parallel to each other and have the same length.

10. The cooling structure according to claim 9, characterized in that, The lengths of the inlet pipe (1) and the outlet pipe (11) are 200-400 mm.

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