Gas absorption tower for low-temperature methanol washing process

Abstract

The utility model belongs to the technical field of gas purification, and relates to a gas absorption tower for a low-temperature methanol washing process, which comprises a tower body, an upper tube plate, a lower tube plate and a plurality of heat exchange tubes, the upper tube plate is positioned at the upper part of the tower body inner cavity; the lower tube plate is positioned at the lower part of the inner cavity of the tower body, and a cooling cavity is formed between the lower tube plate and the upper tube plate; the multiple heat exchange tube nests are evenly arranged in the cooling cavity, the two ends of each heat exchange tube nest are connected with the upper tube plate and the lower tube plate respectively, and low-temperature media are arranged in the heat exchange tube nests or the cooling cavity. The low-temperature medium is arranged in the heat exchange tube nest or the cooling cavity, in the process that the methanol solvent absorbs gas, the low-temperature medium cools the methanol solvent at the same time, the operation of absorbing the gas by the methanol solvent and the operation of cooling the methanol solvent are synchronously carried out, and therefore the methanol solvent is kept in a low-temperature state all the time; the heated methanol solvent does not need to be led out of the tower body for cooling operation, so that the technological process is greatly shortened.

Description

Technical Field

[0001] This utility model relates to the field of gas purification technology, specifically a gas absorption tower for a low-temperature methanol washing process. Background Technology

[0002] Low-temperature methanol washing is a highly efficient gas purification technology widely used in coal gasification, natural gas, and syngas processes to remove acidic gases (such as hydrogen sulfide and carbon dioxide). The core of this process lies in using methanol as a solvent to absorb gases at low temperatures. The gas absorption tower, a key piece of equipment in the process, is responsible for achieving effective contact between the gas and the methanol solvent, thereby allowing impurities in the gas to be absorbed by the methanol.

[0003] The absorption of gas by methanol solvent is an exothermic process; as absorption proceeds, the temperature of the methanol solvent gradually rises. The lower the temperature of the methanol solvent, the stronger its gas absorption capacity. Therefore, maintaining a low temperature in the methanol solvent is crucial for improving gas absorption efficiency.

[0004] There is some research on gas absorption towers for low-temperature methanol washing processes in the prior art. See patent document with application number 201621088290.0, which discloses a low-temperature methanol washing device, including a pre-washing tower, a hydrogen sulfide absorption tower, a carbon dioxide absorption tower, a gas regeneration tower, a first pipeline, a second pipeline, and a third pipeline. The hydrogen sulfide absorption tower includes a pre-washing section and a main tower, and the carbon dioxide absorption tower includes a cooling section and a fine washing section. The top of the fine washing section is connected to a purified gas exhaust pipe, which is equipped with a pH meter, a switch valve, and a purified gas outlet drain valve. The lower end of the purified gas outlet drain valve is connected to a purified gas inlet pipeline, which is connected to the bottom of the gas regeneration tower. An air filter and a cooler are installed on the first pipeline, and a shift gas separator and a cooling device are installed on the third pipeline.

[0005] Therefore, the removal and recovery of acidic gases from crude syngas are achieved through the coordinated operation of the pre-washing tower, hydrogen sulfide absorption tower, carbon dioxide absorption tower, and gas regeneration tower. However, during the gas absorption process, as the methanol solvent continuously absorbs gas, its temperature inevitably rises, leading to a gradual weakening of its absorption capacity. To ensure continuous and efficient gas absorption, measures must be taken to cool the heated methanol solvent after gas absorption. This typically involves drawing the impurity-rich methanol solvent from the bottom of the absorption tower, cooling it through a cooling device to restore its high absorption capacity, and then reintroducing the cooled methanol solvent into the absorption tower to continue participating in the gas absorption process. While these measures maintain the absorption efficiency of the methanol solvent, they increase operational complexity and significantly prolong the entire process. Utility Model Content

[0006] To address the technical problem in the background art that, in order to ensure continuous and efficient gas absorption, measures must be taken to cool down the heated methanol solvent after gas absorption in a timely manner, but the cooling measures increase the complexity of operation and lead to a significant extension of the process flow, this utility model provides a gas absorption tower for a low-temperature methanol washing process.

[0007] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0008] A gas absorption tower for a low-temperature methanol washing process includes a tower body, an upper tube sheet, a lower tube sheet, and multiple heat exchange tubes. The upper tube sheet is connected to the inner wall of the tower body and located in the upper part of the tower body cavity. The lower tube sheet is connected to the inner wall of the tower body and located in the lower part of the tower body cavity. A cooling chamber is formed between the lower tube sheet and the upper tube sheet, which is the inner cavity of the tower body. The multiple heat exchange tubes are evenly arranged in the cooling chamber. The two ends of each heat exchange tube are connected to the upper tube sheet and the lower tube sheet, respectively. A low-temperature medium is provided in the heat exchange tubes or the cooling chamber, and the methanol solvent and the gas to be absorbed react under the cooling conditions of the low-temperature medium.

[0009] Preferably, each of the heat exchange tubes is provided with a low-temperature medium for heat exchange of methanol solvent.

[0010] Preferably, the tower body has a first gas inlet and a first gas outlet on its side wall; both the first gas inlet and the first gas outlet are connected to the inner cavity of the heat exchange tubes, and the first gas inlet is located near the lower tube sheet, while the first gas outlet is located near the upper tube sheet.

[0011] Preferably, the tower body is provided with a first refrigerant inlet and a first refrigerant outlet; both the first refrigerant inlet and the first refrigerant outlet are connected to the cooling chamber, and the first refrigerant inlet is located at the bottom of the tower body, while the first refrigerant outlet is located at the top of the tower body.

[0012] Preferably, the tower body has a first solvent inlet and a first solvent outlet on its side wall; both the first solvent inlet and the first solvent outlet are connected to the inner cavity of the heat exchange tubes, and the first solvent inlet is located near the upper tube sheet, while the first solvent outlet is located near the lower tube sheet.

[0013] Preferably, the cooling chamber is provided with a low-temperature medium for heat exchange of the methanol solvent.

[0014] Preferably, the tower body is provided with a second gas inlet and a second gas outlet; both the second gas inlet and the second gas outlet are connected to the cooling chamber, and the second gas inlet is located at the bottom of the tower body, while the second gas outlet is located at the top of the tower body.

[0015] Preferably, the tower body has a second refrigerant inlet and a second refrigerant outlet on its side wall; both the second refrigerant inlet and the second refrigerant outlet are connected to the inner cavity of the heat exchange tubes, and the second refrigerant inlet is located near the lower tube sheet, and the second refrigerant outlet is located near the upper tube sheet.

[0016] Preferably, the tower body has a second solvent inlet and a second solvent outlet on its side wall; both the second solvent inlet and the second solvent outlet are connected to the cooling chamber, and the second solvent inlet is close to the upper tube sheet, and the second solvent outlet is close to the lower tube sheet.

[0017] In the above technical solution, the present invention has the following beneficial effects:

[0018] (1) The gas absorption tower for the low-temperature methanol washing process of this utility model is equipped with a low-temperature medium in the heat exchange tube or cooling chamber. During the process of methanol solvent absorbing gas, the low-temperature medium simultaneously cools the methanol solvent. The absorption of gas by methanol solvent and the cooling of methanol solvent are carried out synchronously, thereby maintaining the methanol solvent at a low temperature. It is not necessary to lead the heated methanol solvent out of the tower body for cooling, thus greatly shortening the process flow.

[0019] (2) The gas absorption tower for the low-temperature methanol washing process of this utility model introduces refrigerant through a first refrigerant inlet or a second refrigerant inlet. The refrigerant exchanges heat with the low-temperature medium, and after absorbing the heat from the low-temperature medium, it is discharged from the first refrigerant outlet or the second refrigerant outlet, thus completing the cooling of the low-temperature medium. The refrigerant provided facilitates the maintenance of a continuous low-temperature state of the low-temperature medium, thereby ensuring that the low-temperature medium continuously cools the methanol solvent and improving the reliability of the gas absorption tower for the low-temperature methanol washing process. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of Example 2 of the gas absorption tower for the low-temperature methanol washing process of this utility model.

[0021] Figure 2 This is a schematic diagram of the structure of Example 3 of the gas absorption tower for the low-temperature methanol washing process of this utility model.

[0022] In the diagram: 1. Tower body; 2. Heat exchange tubes; 3. Cryogenic medium; 4. First gas inlet; 5. First gas outlet; 6. First refrigerant inlet; 7. First refrigerant outlet; 8. First solvent inlet; 9. First solvent outlet; 10. Second gas inlet; 11. Second gas outlet; 12. Second refrigerant inlet; 13. Second refrigerant outlet; 14. Second solvent inlet; 15. Second solvent outlet. Detailed Implementation

[0023] The technical solution of this utility model will be further explained and described below with reference to the accompanying drawings and embodiments, but this utility model is not limited to the embodiments described below.

[0024] This invention aims to provide a gas absorption tower for a low-temperature methanol washing process. A low-temperature medium 3 is installed in the heat exchange tube 2 or the cooling chamber. During the process of methanol solvent absorbing gas, the low-temperature medium 3 simultaneously cools the methanol solvent. The absorption of gas and the cooling of methanol solvent are carried out synchronously, thereby maintaining the methanol solvent at a low temperature. It is not necessary to lead the heated methanol solvent out of the tower for cooling, thus greatly shortening the process flow.

[0025] Example 1:

[0026] Reference Figure 1 This utility model provides a technical solution: a gas absorption tower for a low-temperature methanol washing process, comprising a tower body 1, an upper tube sheet, a lower tube sheet, and multiple heat exchange tubes 2. The upper tube sheet is connected to the inner wall of the tower body 1 and located at the upper part of the inner cavity of the tower body 1, and the lower tube sheet is connected to the inner wall of the tower body 1 and located at the lower part of the inner cavity of the tower body 1. A cooling cavity is formed between the lower tube sheet and the upper tube sheet, which is the inner cavity of the tower body 1. Multiple heat exchange tubes 2 are evenly arranged in the cooling cavity, and the two ends of the heat exchange tubes 2 are connected to the upper tube sheet and the lower tube sheet, respectively. A low-temperature medium is provided in the heat exchange tubes 2 or the cooling cavity, and the methanol solvent and the gas to be absorbed react under the cooling conditions of the low-temperature medium.

[0027] Specifically, the diameter of the heat exchange tube 2 is D1, and the distance between the centerlines of two adjacent heat exchange tubes 2 is D2. The values ​​of D1 and D2 can be set according to the actual scale of the gas absorption tower, and no specific numerical limit is imposed in this embodiment.

[0028] More specifically, the low-temperature medium 3 is liquid propylene or liquid ammonia, so as to absorb and remove the heat generated by the methanol solvent during the absorption of the gas to be absorbed, thereby cooling the methanol solvent and improving the absorption efficiency of the methanol solvent.

[0029] Example 2:

[0030] Reference Figure 1 In this embodiment, the gas absorption tower for the low-temperature methanol washing process is based on the example 1, with a low-temperature medium 3 for heat exchange of methanol solvent in the cooling chamber.

[0031] In this embodiment, the cryogenic medium 3 is placed inside the heat exchange tube 2. The gas to be absorbed enters the inner cavity of the heat exchange tube 2 from the first gas inlet 4, and the methanol solvent enters the inner cavity of the heat exchange tube 2 from the first solvent inlet 8. Inside the heat exchange tube 2, the gas to be absorbed and the methanol solvent come into countercurrent contact, thereby achieving the absorption of the gas to be absorbed. At the same time, the cryogenic medium 3 flows inside the heat exchange tube 2 and comes into direct contact with the methanol solvent. The cryogenic medium 3 directly absorbs and carries away the heat generated by the methanol solvent during the gas absorption process, thereby keeping the methanol solvent at a low temperature and improving the absorption efficiency of the methanol solvent for the gas to be absorbed.

[0032] Reference Figure 1 The tower body 1 has a first gas inlet 4 and a first gas outlet 5 on its side wall. Both the first gas inlet 4 and the first gas outlet 5 are connected to the inner cavity of the heat exchange tube 2 to ensure smooth flow of the gas to be absorbed. The first gas inlet 4 is located near the lower tube sheet, and the first gas outlet 5 is located near the upper tube sheet to achieve countercurrent absorption of the gas to be absorbed.

[0033] Reference Figure 1 To cool the low-temperature medium 3, the tower body 1 is provided with a first refrigerant inlet 6 and a first refrigerant outlet 7. Both the first refrigerant inlet 6 and the first refrigerant outlet 7 are connected to the cooling chamber for introducing and discharging refrigerant. The first refrigerant inlet 6 is located at the bottom of the tower body 1, and the first refrigerant outlet 7 is located at the top of the tower body 1 to achieve refrigerant circulation.

[0034] In this embodiment, refrigerant is introduced through the first refrigerant inlet 6, circulates in the cooling chamber, and exchanges heat with the cryogenic medium 3; after absorbing heat from the cryogenic medium 3, the refrigerant is discharged from the first refrigerant outlet 7. The refrigerant configuration facilitates maintaining the continuous low temperature of the cryogenic medium 3, thereby ensuring that the cryogenic medium 3 continuously cools the methanol solvent.

[0035] Reference Figure 1 To facilitate the introduction and discharge of methanol solvent, a first solvent inlet 8 and a first solvent outlet 9 are provided on the side wall of the tower body 1. Both the first solvent inlet 8 and the first solvent outlet 9 are connected to the inner cavity of the heat exchange tube 2 to achieve the absorption of the gas to be absorbed by the methanol solvent. The first solvent inlet 8 is located near the upper tube sheet, and the first solvent outlet 9 is located near the lower tube sheet to achieve the circulation of the methanol solvent.

[0036] The working principle of the gas absorption tower for the low-temperature methanol washing process in this embodiment is as follows: the gas to be absorbed enters the inner cavity of the heat exchange tube 2 from the first gas inlet 4, and the methanol solvent enters the inner cavity of the heat exchange tube 2 from the first solvent inlet 8. The gas to be absorbed and the methanol solvent come into countercurrent contact, thereby achieving the absorption of the gas to be absorbed. At the same time, the low-temperature medium 3 flows in the inner cavity of the heat exchange tube 2 and comes into direct contact with the methanol solvent. The low-temperature medium 3 directly absorbs and carries away the heat generated by the methanol solvent during the gas absorption process. The cooled methanol solvent is discharged from the first solvent outlet 9 and then reintroduced into the inner cavity of the heat exchange tube 2 from the first solvent inlet 8 to participate in the absorption process of the gas to be absorbed again.

[0037] Example 3:

[0038] Reference Figure 2 In this embodiment, the gas absorption tower for the low-temperature methanol washing process is based on the example 1, with a low-temperature medium 3 for heat exchange of methanol solvent in the cooling chamber.

[0039] In this embodiment, the cryogenic medium 3 is placed in the cooling chamber, the gas to be absorbed enters the cooling chamber from the second gas inlet 10, and the methanol solvent enters the cooling chamber from the second solvent inlet 14. In the cooling chamber, the gas to be absorbed and the methanol solvent come into countercurrent contact to achieve absorption of the gas to be absorbed. At the same time, the cryogenic medium 3 flows in the cooling chamber and comes into direct contact with the methanol solvent. The cryogenic medium 3 directly absorbs and carries away the heat generated by the methanol solvent in the process of absorbing the gas to be absorbed, thereby keeping the methanol solvent at a low temperature and improving the absorption efficiency of the methanol solvent in absorbing the gas to be absorbed.

[0040] Reference Figure 2 The tower body 1 is provided with a second gas inlet 10 and a second gas outlet 11. Both the second gas inlet 10 and the second gas outlet 11 are connected to the cooling chamber to ensure smooth flow of the gas to be absorbed. The second gas inlet 10 is located at the bottom of the tower body 1, and the second gas outlet 11 is located at the top of the tower body 1 to achieve countercurrent absorption of the gas to be absorbed.

[0041] Reference Figure 2 To cool the low-temperature medium 3, a second refrigerant inlet 12 and a second refrigerant outlet 13 are provided on the side wall of the tower body 1. Both the second refrigerant inlet 12 and the second refrigerant outlet 13 are connected to the inner cavity of the heat exchange tubes 2 for introducing and discharging refrigerant. The second refrigerant inlet 12 is located near the lower tube sheet, and the second refrigerant outlet 13 is located near the upper tube sheet to achieve refrigerant circulation.

[0042] In this embodiment, refrigerant is introduced through the second refrigerant inlet 12. The refrigerant circulates within the heat exchange tube 2 and exchanges heat with the cryogenic medium 3. After absorbing heat from the cryogenic medium 3, the refrigerant is discharged from the second refrigerant outlet 13. The refrigerant is designed to maintain the cryogenic medium 3 at a continuous low temperature, thereby ensuring that the cryogenic medium 3 continuously cools the methanol solvent.

[0043] Reference Figure 2 To facilitate the introduction and discharge of methanol solvent, a second solvent inlet 14 and a second solvent outlet 15 are provided on the side wall of the tower body 1. Both the second solvent inlet 14 and the second solvent outlet 15 are connected to the cooling chamber to achieve the absorption of the gas to be absorbed by the methanol solvent. The second solvent inlet 14 is located near the upper tube sheet, and the second solvent outlet 15 is located near the lower tube sheet to achieve the circulation of the methanol solvent.

[0044] The working principle of the gas absorption tower for the low-temperature methanol washing process in this embodiment is as follows: the gas to be absorbed enters the cooling chamber from the second gas inlet 10, and the methanol solvent enters the cooling chamber from the second solvent inlet 14. The gas to be absorbed and the methanol solvent come into countercurrent contact to achieve absorption of the gas to be absorbed. At the same time, the low-temperature medium 3 flows in the cooling chamber and comes into direct contact with the methanol solvent. The low-temperature medium 3 directly absorbs and carries away the heat generated by the methanol solvent in the process of absorbing the gas. The cooled methanol solvent is discharged from the second solvent inlet 14 and then reintroduced into the cooling chamber from the second solvent inlet 14 to participate in the absorption process of the gas to be absorbed again.

[0045] The above are all preferred embodiments of this utility model, and are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape and principle of this utility model should be covered within the scope of protection of this utility model.

Claims

1. A gas absorption column for use in a low temperature methanol wash process, characterized by: The utility model relates to a kind of tower body (1); Upper tube plate, with the inner wall of the tower body (1) is connected and is located in the upper portion of the inner cavity of tower body (1); Lower tube plate, with the inner wall of the tower body (1) is connected and is located in the lower portion of the inner cavity of tower body (1), the lower tube plate is formed with upper tube plate between cooling cavity, the cooling cavity is the inner cavity of tower body (1); And a plurality of heat exchange tubes (2), a plurality of the heat exchange tubes (2) are uniformly arranged in cooling cavity, the both ends of the heat exchange tubes (2) are connected with upper tube plate and lower tube plate respectively, low-temperature medium is arranged in the heat exchange tubes (2) or cooling cavity, methanol solvent and to be absorbed gas react under the cooling condition of low-temperature medium. Low-temperature medium (3) for heat exchange of methanol solvent is arranged in each heat exchange tube (2).

2. The gas absorption column for a rectisol process according to claim 1, characterized in that: The side wall of the tower body (1) is provided with a first gas inlet (4) and a first gas outlet (5); 3. The gas absorbing column for a rectisol process according to claim 2, characterized in that: The first gas inlet (4) and the first gas outlet (5) are both communicated with the inner cavity of the heat exchange tube (2), and the first gas inlet (4) is arranged close to the lower tube plate, and the first gas outlet (5) is arranged close to the upper tube plate. The tower body (1) is provided with a first refrigerant inlet (6) and a first refrigerant outlet (7) on the upper portion of the tower body (1); 4. The rectisol gas absorption column of claim 3, wherein: The first refrigerant inlet (6) and the first refrigerant outlet (7) are both communicated with the cooling cavity, and the first refrigerant inlet (6) is located at the bottom of the tower body (1), and the first refrigerant outlet (7) is located at the top of the tower body (1). The side wall of the tower body (1) is provided with a first solvent inlet (8) and a first solvent outlet (9); 5. The rectisol gas absorption column of claim 4, wherein: The first solvent inlet (8) and the first solvent outlet (9) are both communicated with the inner cavity of the heat exchange tube (2), and the first solvent inlet (8) is arranged close to the upper tube plate, and the first solvent outlet (9) is arranged close to the lower tube plate. Low-temperature medium (3) for heat exchange of methanol solvent is arranged in the cooling cavity.

6. The rectisol process gas absorption column of claim 1, wherein: The tower body (1) is provided with a second gas inlet (10) and a second gas outlet (11) on the upper portion of the tower body (1); 7. The rectisol gas absorption column of claim 6, wherein: The second gas inlet (10) and the second gas outlet (11) are both communicated with the cooling cavity, and the second gas inlet (10) is located at the bottom of the tower body (1), and the second gas outlet (11) is located at the top of the tower body (1). The side wall of the tower body (1) is provided with a second refrigerant inlet (12) and a second refrigerant outlet (13); 8. The rectisol process gas absorption column of claim 7, wherein: The second refrigerant inlet (12) and the second refrigerant outlet (13) are both communicated with the inner cavity of the heat exchange tube (2), and the second refrigerant inlet (12) is arranged close to the lower tube plate, and the second refrigerant outlet (13) is arranged close to the upper tube plate. The side wall of the tower body (1) is provided with a second solvent inlet (14) and a second solvent outlet (15); 9. The rectisol gas absorption column of claim 8, wherein: The second solvent inlet (14) and the second solvent outlet (15) are both communicated with the cooling cavity, and the second solvent inlet (14) is arranged close to the upper tube plate, and the second solvent outlet (15) is arranged close to the lower tube plate. ​

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