Device for reforming methane in underground coal gasification product gas and reducing temperature

What is AI technical title?
AI technical title is built by Patsnap AI team. It summarizes the technical point description of the patent document.
By using a vertical coaxial three-tube heat exchange reactor and a methane reforming catalyst in an underground coal gasification unit, the conversion of methane to CO and the reduction of temperature were achieved, solving the problems of insufficient components in the product gas and high-temperature damage to the well, and reducing the equipment scale and investment cost.

CN224221306UActive Publication Date: 2026-05-12ZHONGWEI SHANGHAI ENERGY TECH CO LTD

View PDF 0 Cites 0 Cited by

Patent Information

Authority / Receiving Office: CN · China
Patent Type: Utility models(China)
Current Assignee / Owner: ZHONGWEI SHANGHAI ENERGY TECH CO LTD
Filing Date: 2025-05-28
Publication Date: 2026-05-12

AI Technical Summary

Technical Problem

In existing underground coal gasification technologies, the CO and component content in the product gas is insufficient, and the high-temperature product gas can easily damage the product well, resulting in large-scale equipment and high investment costs for subsequent syngas chemical industry.

Method used

A vertical coaxial three-tube heat exchange reactor and a methane reforming catalyst are used to convert methane into CO and CO2 in the product well of the underground coal gasification unit through a methane reforming reaction. At the same time, the heat of the high-temperature gas itself is used to reduce the temperature of the product gas.

Benefits of technology

It increases the CO content in the product gas, reduces the temperature requirements of the product well, decreases equipment investment and material costs, and protects the product well from high-temperature damage.

✦ Generated by Eureka AI based on patent content.

Smart Images

Figure CN224221306U_ABST

Patent Text Reader

Abstract

The utility model relates to the technical field of underground coal gas, in particular to a device for reforming methane in underground coal gasification product gas and reducing the temperature, which comprises a vertical coaxial three-sleeve heat exchange type reactor and a methane reforming catalyst, the vertical coaxial three-sleeve heat exchange type reactor comprises an inner-layer sleeve, a middle-layer sleeve and an outer-layer sleeve which are sequentially arranged from inside to outside, the middle-layer sleeve is filled with a methane reforming catalyst, and the vertical coaxial three-sleeve heat exchange type reactor is installed in a coal underground gasification device product well; a product gas outlet is formed in the top of the vertical coaxial three-sleeve heat exchange type reactor, and a product gas inlet is formed in the bottom of the vertical coaxial three-sleeve heat exchange type reactor; the device is arranged in the product well of the underground coal gasification device, methane in the gas is subjected to reforming reaction by utilizing the heat of the product gas to produce CO and H2, and the temperature of the gas is reduced, so that the requirement of the product well of the underground coal gasification device on the aspect of high temperature resistance is greatly reduced.

Need to check novelty before this filing date? Find Prior Art

Description

Technical Field

[0001] This utility model relates to the field of underground coal gas technology, and in particular to a device for reforming and reducing the temperature of methane in underground coal gasification product gas. Background Technology

[0002] Underground coal gasification is a process that directly converts coal into product gas through controlled combustion and gasification reactions in underground coal seams in the presence of an oxidant. This product gas is usually called product coal gas or crude syngas. It can then be used as a feedstock for a variety of applications, including fuel production, chemical production, and power generation. This underground coal gasification technology is applicable to most coal deposits. Given the increasingly stringent environmental and safety requirements for the mining industry and considering the associated labor and infrastructure costs, underground coal gasification technology is undoubtedly very attractive.

[0003] The product gas (crude syngas) generated through underground coal gasification typically contains CO. , , The effective components, and their relative proportions, depend on several factors: the type of oxidant used in underground coal gasification (air or other oxidants, such as oxygen, oxygen-enriched air, or a mixture of steam), the inherent water in the coal seam or water seeping into the coal seam from surrounding strata, the coal quality, and the operating parameters of the underground coal gasification process, including temperature and pressure. If the product gas generated by underground coal gasification is used as feedstock for downstream syngas chemical industries, then its main effective component is CO. , and For subsequent syngas chemical industries, if the goal is to produce fertilizers, methanol, olefins, or synthetic oils, further treatment of the product gas is usually required. It is converted into CO and through a reforming reaction. Therefore, it is necessary to maximize the CO and CO content in the product gas. The composition content will greatly reduce and save on the equipment scale and investment costs of the methane reforming section in subsequent surface syngas chemical plants. In addition, one problem that underground coal gasification technology has long faced is how to overcome the series of technical and equipment cost problems brought about by the high temperature of the product gas that the product well needs to withstand.

[0004] Therefore, if the existing coal gas is to be used as feedstock in the downstream syngas chemical industry, the component content needs to be increased. The product wells also need to withstand high-temperature product gas, which can easily damage them. A device could be designed to reform the methane in the underground coal gasification product gas and lower its temperature. This methane reforming reaction could reform methane into CO and CO2. It is also a strongly endothermic reaction. By installing the casing-type methane catalytic reforming reactor disclosed in this invention in the product well of an underground coal gasification plant, the two problems mentioned above can be effectively solved simultaneously, increasing the CO and... The concentrations of these two effective components further reduced the temperature of the product gas in the product well. Utility Model Content

[0005] To overcome the existing problems that if the product gas is used as feedstock in the downstream syngas chemical industry, the composition content needs to be increased, the product well needs to withstand high-temperature product gas, and high-temperature product gas can easily damage the product well.

[0006] The technical solution of this utility model is as follows: a device for reforming and reducing the temperature of methane in underground coal gasification product gas, comprising a vertical coaxial three-tube heat exchange reactor and a methane reforming catalyst. The vertical coaxial three-tube heat exchange reactor includes an inner tube, a middle tube, and an outer tube arranged sequentially from the inside to the outside. The methane reforming catalyst is filled in the middle tube. The vertical coaxial three-tube heat exchange reactor is installed in the product well of the underground coal gasification device. The top of the vertical coaxial three-tube heat exchange reactor is the product gas outlet. Several heat exchange fins are welded on the tube wall of the inner tube. The bottom of the vertical coaxial three-tube heat exchange reactor is the product gas inlet.

[0007] Preferably, the vertical coaxial three-tube heat exchange reactor is hoisted in the product well of the underground coal gasification unit. The bottom of the vertical coaxial three-tube heat exchange reactor is the product gas inlet. Product coal gas with a temperature of about 1000°C from the gasification zone enters the vertical coaxial three-tube heat exchange reactor from the product gas inlet. The top of the vertical coaxial three-tube heat exchange reactor is the product gas outlet. The low-temperature gas after the methane reforming reaction is sent to the downstream unit on the ground from the product gas outlet.

[0008] After the high-temperature gas enters the vertical coaxial three-tube heat exchange reactor through the bottom product gas inlet, it first flows from bottom to top in the inner tube. After reaching the top, the temperature of the gas flowing in the inner tube drops to about 800-900℃. During this process, the heat of the high-temperature gas is continuously transferred to the methane reforming catalyst bed in the middle tube on the other side of the tube wall between the inner tube and the middle tube, so as to provide it with the heat required for the methane reforming reaction. Several fins are welded on the tube wall of the inner tube to enhance the heat transfer efficiency.

[0009] The top of the intermediate sleeve is connected to the top of the inner sleeve. After reaching the top, the gas in the inner sleeve flows back down into the intermediate sleeve through this connection. As it flows downward through the methane reforming catalyst bed, a methane reforming reaction occurs due to the presence of the catalyst. Most of the methane in the gas is converted into CO and other gases through the reaction. The reaction formula is: 2 + 0+ =3+5 ΔH=454.1KJ / mol. As can be seen from the reaction formula, the catalytic reforming reaction of methane is a strongly endothermic reaction. A large amount of heat needs to be absorbed during the reaction process, and the source of this heat is provided by the high-temperature gas flowing in the opposite direction inside the inner sleeve.

[0010] The bottom end of the intermediate casing is connected to the bottom end of the outer casing. After the gas in the intermediate casing reaches the bottom, the temperature of the gas is further reduced by 500-600℃. After passing through this connection, it flows back upward into the outer casing. Since the gas temperature here is much lower than the temperature before the reaction, the gas flowing from bottom to top along the outer casing forms a "cold wall" effect, which plays a "wrapping" role for the high-temperature part of the entire vertical coaxial three-tube heat exchange reactor, so that the product well of the underground coal gasification unit can be protected from damage by high-temperature gas.

[0011] As a preferred option, the vertical coaxial three-tube heat exchange reactor has a columnar structure, with the inner tube, middle tube, and outer tube made of stainless steel or nickel-based alloy steel.

[0012] Preferably, the methane reforming catalyst is a rhodium-based or nickel-based catalyst.

[0013] Preferably, both the inner and outer sleeves have hollow internal structures.

[0014] Preferably, the top end of the intermediate sleeve is connected to the top end of the inner sleeve, and the bottom end of the intermediate sleeve is connected to the bottom end of the outer sleeve.

[0015] Preferably, the flow directions of the product gas in the inner and middle casings are opposite to each other, and the product gas at the product gas inlet comes from the gasification zone of the underground coal gasification unit.

[0016] Preferably, the product gas inlet is connected to the inner sleeve, and the product gas outlet is connected to the outer sleeve.

[0017] The beneficial effects of this invention are: it is installed in the product well of an underground coal gasification unit, utilizing the heat of the product gas itself to produce CO and other gases from methane through a reforming reaction. The device, which reduces the content and temperature of the gas, mainly comprises a coaxial three-tube reactor and a methane reforming catalyst packed in the intermediate tube. The reactor is an integrated structure with three tubes, featuring high reaction and heat exchange efficiency, maintenance-free operation, and easy replacement. Utilizing the methane reforming catalyst in the intermediate tube, the product gas from the underground coal gasification unit undergoes a methane reforming reaction to reduce the content and temperature of the gas. Reforming into CO and This increases the CO and CO content in the product gas from underground coal gasification plants. The content of methane reforming is also reduced. Since the methane reforming reaction is a strongly endothermic reaction, the product gas temperature of the product well of the underground coal gasification unit is greatly reduced after the product gas fully utilizes its own heat to carry out the methane reforming reaction. This greatly reduces the requirements for high temperature resistance of the product well of the underground coal gasification unit, thereby greatly reducing the requirements for high temperature resistant materials and investment costs of the product well of the underground coal gasification unit. Attached Figure Description

[0018] Figure 1 The diagram shown is a cross-sectional view of the device for reforming methane in underground coal gasification product gas and reducing its temperature.

[0019] Explanation of reference numerals in the attached diagram: 1. Product gas outlet; 2. Heat exchange fins; 3. Inner casing; 4. Intermediate casing; 5. Outer casing; 6. Product well of underground coal gasification unit; 7. Product gas inlet; 8. Gasification zone. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Please see Figure 1 This utility model provides an embodiment: a device for reforming and reducing the temperature of methane in underground coal gasification product gas, comprising a vertical coaxial three-tube heat exchange reactor and a methane reforming catalyst. The vertical coaxial three-tube heat exchange reactor includes an inner tube 3, a middle tube 4, and an outer tube 5 arranged sequentially from the inside to the outside. The methane reforming catalyst is filled in the middle tube 4. The vertical coaxial three-tube heat exchange reactor is installed in the product well 6 of the underground coal gasification device. The top of the vertical coaxial three-tube heat exchange reactor is the product gas outlet 1. Several heat exchange fins 2 are welded to the tube wall of the inner tube 3. The bottom of the vertical coaxial three-tube heat exchange reactor is the product gas inlet 7.

[0022] Among them, the vertical coaxial three-tube heat exchange reactor has a columnar structure. The inner tube 3, the middle tube 4 and the outer tube 5 are made of stainless steel or nickel-based alloy steel, and the methane reforming catalyst is a rhodium-based or nickel-based catalyst.

[0023] Meanwhile, both the inner casing 3 and the outer casing 5 have hollow structures inside. The top of the intermediate casing 4 is connected to the top of the inner casing 3, and the bottom of the intermediate casing 4 is connected to the bottom of the outer casing 5. The flow direction of the product gas in the inner casing 3 and the intermediate casing 4 is opposite to each other. The product gas at the product gas inlet 7 comes from the gasification zone 8 of the underground coal gasification unit.

[0024] In addition, the product gas inlet 7 is connected to the inner sleeve 3, and the product gas outlet 1 is connected to the outer sleeve 5.

[0025] During operation, the vertical coaxial three-tube heat exchange reactor is hoisted in the product well 6 of the underground coal gasification unit. The bottom of the vertical coaxial three-tube heat exchange reactor is the product gas inlet 7. Product coal gas with a temperature of about 1000℃ from the gasification zone 8 enters the vertical coaxial three-tube heat exchange reactor through the product gas inlet 7. The top of the vertical coaxial three-tube heat exchange reactor is the product gas outlet 1. The low-temperature gas after the methane reforming reaction is sent to the downstream unit on the ground through the product gas outlet 1.

[0026] After the high-temperature gas enters the vertical coaxial three-tube heat exchange reactor through the bottom product gas inlet 7, it first flows from bottom to top in the inner tube 3. After reaching the top, the temperature of the gas flowing in the inner tube 3 drops to about 800-900℃. During this process, the heat of the high-temperature gas is continuously transferred to the methane reforming catalyst bed in the middle tube 4 on the other side of the tube wall between the inner tube 3 and the middle tube 4, so as to provide it with the heat required for the methane reforming reaction. Several fins are welded on the tube wall of the inner tube 3 to enhance the heat transfer efficiency.

[0027] The top end of the intermediate sleeve 4 is connected to the top end of the inner sleeve 3. After reaching the top, the gas in the inner sleeve 3 flows back down into the intermediate sleeve 4 through this connection. As it flows downward through the methane reforming catalyst bed, a methane reforming reaction occurs due to the presence of the methane reforming catalyst. Most of the methane in the gas is converted into CO and other gases through the reaction. The reaction formula is: 2 + 0+ =3+5 ΔH=454.1KJ / mol. As can be seen from the reaction formula, the catalytic reforming reaction of methane is a strongly endothermic reaction. A large amount of heat needs to be absorbed during the reaction process. The source of this heat is provided by the high-temperature gas flowing in the countercurrent inside the inner sleeve 3.

[0028] The bottom end of the intermediate layer casing 4 is connected to the bottom end of the outer layer casing 5. After the gas in the intermediate layer casing 4 reaches the bottom, the temperature of the gas is further reduced by 500-600°C. After passing through this connection, the gas flows back upward into the outer layer casing 5. Since the gas temperature here is much lower than the temperature before the reaction, the gas flowing from bottom to top along the outer layer casing 5 forms a "cold wall" effect, which plays a "wrapping" role for the high-temperature part of the entire vertical coaxial three-tube heat exchange reactor, so that the product well 6 of the underground coal gasification unit can be protected from damage by high-temperature gas.

[0029] Through the above steps, by setting up a product well 6 in the underground coal gasification unit, the heat of the product gas itself is used to reform the methane in the gas to produce CO and other gases. The device for reducing the content and temperature of the gas mainly includes a coaxial three-tube reactor and a methane reforming catalyst packed in the intermediate tube. The reactor is an integrated structure with three tubes, featuring high reaction and heat exchange efficiency, maintenance-free operation, and easy replacement. Utilizing the methane reforming catalyst located in the intermediate tube, the product gas from the underground coal gasification unit is purified through a methane reforming reaction. Reforming into CO and This increases the CO and CO content in the product gas from underground coal gasification plants. The content of the product gas is significantly reduced. Furthermore, since methane reforming is a strongly endothermic reaction, the product gas, after fully utilizing its own heat for the methane reforming reaction, greatly reduces the outlet temperature of the product gas from well 6 of the underground coal gasification unit. This significantly lowers the high-temperature resistance requirements of well 6, thereby greatly reducing the high-temperature material requirements and investment costs. This addresses the existing problem that if the product gas is used as feedstock for downstream syngas chemical industries, the component content needs to be increased, and the product well needs to withstand high-temperature product gas, which can easily damage the product well.

[0030] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. An apparatus for reforming and reducing the temperature of methane in underground coal gasification product gas, comprising a vertical coaxial three-tube heat exchange reactor and a methane reforming catalyst, characterized in that: The vertical coaxial three-tube heat exchange reactor includes an inner tube (3), a middle tube (4) and an outer tube (5) arranged sequentially from the inside to the outside. The methane reforming catalyst is filled in the middle tube (4). The vertical coaxial three-tube heat exchange reactor is installed in the product well (6) of the underground coal gasification unit. The top of the vertical coaxial three-tube heat exchange reactor is the product gas outlet (1). Several heat exchange fins (2) are welded on the tube wall of the inner tube (3). The bottom of the vertical coaxial three-tube heat exchange reactor is the product gas inlet (7).

2. The apparatus for reforming and reducing the temperature of methane in underground coal gasification product gas according to claim 1, characterized in that: The vertical coaxial three-tube heat exchange reactor has a columnar structure, with the inner tube (3), middle tube (4) and outer tube (5) made of stainless steel or nickel-based alloy steel.

3. The apparatus for reforming and reducing the temperature of methane in underground coal gasification product gas according to claim 1, characterized in that: The methane reforming catalyst is a rhodium-based or nickel-based catalyst.

4. The apparatus for reforming and reducing the temperature of methane in underground coal gasification product gas according to claim 1, characterized in that: Both the inner sleeve (3) and the outer sleeve (5) have hollow internal structures.

5. The apparatus for reforming and reducing the temperature of methane in underground coal gasification product gas according to claim 1, characterized in that: The top end of the intermediate sleeve (4) is connected to the top end of the inner sleeve (3), and the bottom end of the intermediate sleeve (4) is connected to the bottom end of the outer sleeve (5).

6. The apparatus for reforming and reducing the temperature of methane in underground coal gasification product gas according to claim 1, characterized in that: The flow directions of the product gas in the inner casing (3) and the middle casing (4) are opposite to each other, and the product gas at the product gas inlet (7) comes from the gasification zone (8) of the underground coal gasification unit.

7. The apparatus for reforming and reducing the temperature of methane in underground coal gasification product gas according to claim 1, characterized in that: The product gas inlet (7) is connected to the inner sleeve (3), and the product gas outlet (1) is connected to the outer sleeve (5).