Methanol synthesis flash steam recycling device

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By designing a flash vapor recovery and reuse device for methanol synthesis, the multi-stage flash vapor and washing process are used to reduce the amount of methanol entrainment, the problems of methanol loss and low gas-liquid separation efficiency in methanol synthesis process are solved, and efficient methanol recovery and improvement of gas-liquid separation efficiency are achieved.

CN222765681UActive Publication Date: 2025-04-18LEVIMA ADVANCED MATERIALS CORP

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Patent Information

Application Number: CN202421571041.1
Authority / Receiving Office: CN · China
Patent Type: Utility models(China)
Current Assignee / Owner
Filing Date: 2024-07-04
Publication Date: 2025-04-18
Estimated Expiration: 2034-07-04

AI Technical Summary

Technical Problem

In methanol synthesis process, during the flash evaporation of crude methanol, methanol is easily entrained into the gas-phase component, resulting in methanol loss and low gas-liquid separation efficiency.

Method used

A methanol synthetic flash vapor recovery and reuse device is designed, including a heat exchanger, a methanol scrubber, a flash vapor module and a flash pressing unit. The amount of methanol entrainment is reduced through the multi-stage flash vapor and washing process, and the flash vapor is reused.

Benefits of technology

It effectively reduces the amount of methanol entrainment in the flash vapor, reduces the loss of methanol with gas phase components, and improves the gas-liquid separation efficiency and methanol recovery rate.

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Abstract

The utility model discloses a methanol synthesis flash steam recycling device which comprises a heat exchanger 1, a methanol washing tower, a heat exchanger 2, a delivery purification gas valve group, a first-stage flash evaporation module, a second-stage flash evaporation module, a carbon dioxide desorption tower and a flash press unit, shift gas is connected with the heat exchanger 1 through a shift gas pipeline, the heat exchanger 1 is connected with the methanol washing tower, the methanol washing tower is connected with the heat exchanger 2, the heat exchanger 2 is connected with the heat exchanger 1, and the heat exchanger 1 is connected with a delivery purification gas valve group; the methanol washing tower is connected with the first-stage flash evaporation module, the first-stage flash evaporation module is connected with the second-stage flash evaporation module, the second-stage flash evaporation module is connected with the carbon dioxide desorption tower, the first-stage flash evaporation module and the second-stage flash evaporation module are connected with the flash pressure unit, and the flash pressure unit is connected with the conversion gas pipeline. The method has the advantages that the methanol entrainment amount in flash steam is reduced, the loss of methanol along with gas-phase components is reduced, and the gas-liquid separation efficiency and the methanol recovery rate are improved.

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Description

Technical Field

[0001] The utility model relates to the technical field of flash gas recovery and utilization, in particular to a methanol synthesis flash gas recovery and reuse device. Background Art

[0002] The coal-to-methanol production process mainly includes gasification, purification, methanol synthesis, and distillation processes; the methanol synthesis process is to react the purified gas under a certain temperature, pressure, and catalyst to generate methanol, and the gas after the reaction is cooled, condensed, and separated into liquid methanol through gas-liquid separation, and the liquid methanol is flashed to obtain a crude methanol product. In the methanol synthesis process, the flash evaporation of crude methanol is an important process, and its purpose is to preliminarily separate the light component impurities such as CO, H2, CO2, and DME dissolved in methanol through the principle of reduced pressure flash evaporation. Methanol flash gas is the gas phase component discharged after the crude methanol is flashed under reduced pressure, which will carry some methanol droplets. How to reduce the amount of methanol entrained, reduce the loss of methanol with the gas phase components, and improve the gas-liquid separation efficiency and methanol yield are problems that need to be solved in the current methanol synthesis process. Utility Model Content

[0003] The purpose of the utility model is to provide a methanol synthesis flash gas recovery and reuse device, so as to solve the above-mentioned problems existing in the prior art.

[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0005] A methanol synthesis flash gas recovery and reuse device comprises a heat exchanger 1, a methanol washing tower, a heat exchanger 2, an external purified gas valve group, a primary flash evaporation module, a secondary flash evaporation module, a carbon dioxide analysis tower and a flash compression unit; the conversion gas delivered from the low-temperature methanol washing station is connected to the conversion gas input end of the heat exchanger 1 through a conversion gas pipeline, the conversion gas output end of the heat exchanger 1 is connected to the input end of the methanol washing tower, the top output end of the methanol washing tower is connected to the input end of the heat exchanger 2, the output end of the heat exchanger 2 is connected to the purified gas input end of the heat exchanger 1, and the purified gas output end of the heat exchanger 1 is connected to the external purified gas valve group;

[0006] The middle output end and the bottom output end of the methanol washing tower are both connected to the first-level flash evaporation module, the liquid phase output end of the first-level flash evaporation module is connected to the input end of the second-level flash evaporation module, the liquid phase output end of the second-level flash evaporation module is connected to the carbon dioxide analysis tower, the gas phase output ends of the first-level flash evaporation module and the second-level flash evaporation module are connected to the input end of the flash compression unit, and the output end of the flash compression unit is connected to the conversion gas pipeline.

[0007] Preferably, a conversion gas inlet valve to the washing tower is provided on the connecting pipe between the heat exchanger 1 and the methanol washing tower.

[0008] Preferably, the primary flash module comprises a flash tank 1 and a flash tank 3, the middle output end and the bottom output end of the methanol washing tower are connected to the flash tank 1 and the flash tank 3 respectively, the liquid phase output ends of the flash tank 1 and the flash tank 3 are connected to the input end of the secondary flash tank; the gas phase output ends of the flash tank 1 and the flash tank 3 are connected to the input end of the flash compression unit.

[0009] Preferably, the gas phase output ends of the flash tank 1 and the flash tank 3 are connected to the input end of the flash compressor unit via a first-stage flash gas inlet flash compressor pipeline; a first-stage flash gas inlet flash compressor valve is provided on the first-stage flash gas inlet flash compressor pipeline.

[0010] Preferably, the secondary flash module includes a flash tank 2 and a flash tank 4, the liquid phase output ends of the flash tank 1 and the flash tank 3 are respectively connected to the input ends of the flash tank 2 and the flash tank 4, the liquid phase output ends of the flash tank 2 and the flash tank 4 are connected to the carbon dioxide analysis tower, and the gas phase output ends of the flash tank 2 and the flash tank 4 are connected to the input end of the flash compression unit.

[0011] Preferably, the gas phase output ends of the flash tank 2 and the flash tank 4 are connected to the input end of the flash compressor unit via a secondary flash gas inlet flash compressor pipeline; a secondary flash gas inlet flash compressor valve is provided on the secondary flash gas inlet flash compressor pipeline.

[0012] Preferably, a first valve for the flash tank to enter the decomposition tower is provided on the connecting pipe between the flash tank 2 and the carbon dioxide decomposition tower; a second valve for the flash tank to enter the decomposition tower is provided on the connecting pipe between the flash tank 4 and the carbon dioxide decomposition tower.

[0013] Preferably, a flash gas inlet system valve is provided on the connecting pipeline between the flash compression unit and the conversion gas pipeline.

[0014] Preferably, the flash compressor unit includes four flash compressors connected in series.

[0015] Preferably, a circulating water heat exchanger is provided in the cylinder of the flash compressor.

[0016] The utility model has the following beneficial effects: the purified gas is separated from methanol by a methanol washing tower, the purified gas is then sent to synthesis after heat exchange, the crude methanol is flash-evaporated and purified by primary and secondary flash evaporation modules, and the flash gas generated during the flash evaporation process is collected in the system for reuse. The amount of methanol entrained in the flash gas is reduced, the loss of methanol with gas phase components is reduced, and the gas-liquid separation efficiency and methanol recovery rate are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram of the recycling and reuse device in the embodiment of the utility model;

[0018] Figure 2 It is a structural diagram of a circulating water heat exchanger in an embodiment of the utility model. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation methods described here are only used to explain the utility model and are not used to limit the utility model.

[0020] like Figure 1 As shown, in this embodiment, a methanol synthesis flash gas recovery and reuse device is provided, comprising a heat exchanger 1, a methanol washing tower, a heat exchanger 2, an external purified gas valve group, a primary flash evaporation module, a secondary flash evaporation module, a carbon dioxide analysis tower and a flash compression unit; the conversion gas delivered from the low-temperature methanol washing station is connected to the conversion gas input end of the heat exchanger 1 through a conversion gas pipeline, the conversion gas output end of the heat exchanger 1 is connected to the input end of the methanol washing tower, the top output end of the methanol washing tower is connected to the input end of the heat exchanger 2, the output end of the heat exchanger 2 is connected to the purified gas input end of the heat exchanger 1, and the purified gas output end of the heat exchanger 1 is connected to the external purified gas valve group;

[0021] The middle output end and the bottom output end of the methanol washing tower are both connected to the first-level flash evaporation module, the liquid phase output end of the first-level flash evaporation module is connected to the input end of the second-level flash evaporation module, the liquid phase output end of the second-level flash evaporation module is connected to the carbon dioxide analysis tower, the gas phase output ends of the first-level flash evaporation module and the second-level flash evaporation module are connected to the input end of the flash compression unit, and the output end of the flash compression unit is connected to the conversion gas pipeline.

[0022] In this embodiment, a conversion gas inlet valve is provided on the connecting pipe between the heat exchanger 1 and the methanol washing tower.

[0023] In this embodiment, the primary flash module includes a flash tank 1 and a flash tank 3, the middle output end and the bottom output end of the methanol washing tower are connected to the flash tank 1 and the flash tank 3 respectively, the liquid phase output ends of the flash tank 1 and the flash tank 3 are connected to the input end of the secondary flash tank; the gas phase output ends of the flash tank 1 and the flash tank 3 are connected to the input end of the flash compression unit.

[0024] The gas phase output ends of the flash tank 1 and the flash tank 3 are connected to the input end of the flash compressor unit through a first-level flash gas inlet flash compressor pipeline; a first-level flash gas inlet flash compressor valve is arranged on the first-level flash gas inlet flash compressor pipeline.

[0025] The secondary flash module includes a flash tank 2 and a flash tank 4, wherein the liquid phase output ends of the flash tank 1 and the flash tank 3 are respectively connected to the input ends of the flash tank 2 and the flash tank 4, the liquid phase output ends of the flash tank 2 and the flash tank 4 are connected to the carbon dioxide analysis tower, and the gas phase output ends of the flash tank 2 and the flash tank 4 are connected to the input end of the flash compression unit.

[0026] The gas phase output ends of the flash tank 2 and the flash tank 4 are connected to the input end of the flash compressor unit through a secondary flash gas inlet flash compressor pipeline; a secondary flash gas inlet flash compressor valve is arranged on the secondary flash gas inlet flash compressor pipeline.

[0027] In this embodiment, a first valve for the flash tank to enter the carbon dioxide desorption tower is provided on the connecting pipe between the flash tank 2 and the carbon dioxide desorption tower; a second valve for the flash tank to enter the carbon dioxide desorption tower is provided on the connecting pipe between the flash tank 4 and the carbon dioxide desorption tower.

[0028] In this embodiment, a flash gas inlet system valve is provided on the connecting pipeline between the flash compression unit and the conversion gas pipeline.

[0029] In this embodiment, the flash compressor unit includes four flash compressors connected in series. Figure 1 The flash press ABCD in the. Figure 2 As shown, a circulating water heat exchanger is arranged in the cylinder of the flash compressor, which is used to cool down the high-pressure flash steam after being pressurized by the flash compressor. The circulating water inlet of the circulating water heat exchanger is connected to the circulating water pipe of the flash compressor, which is used to continuously provide cold water to the circulating water heat exchanger to cool down the high-pressure flash steam.

[0030] In this embodiment, the working principle of the recycling device is as follows: the conversion gas from the low-temperature methanol washing station is processed and enters the heat exchanger 1 through the conversion gas pipeline for precooling, and the precooled conversion gas enters the methanol washing tower through the conversion gas inlet washing tower valve. The purified gas after washing is first heated by the heat exchanger 2, and then heated by the second heat exchanger. The purified gas after heating is sent to the synthesis through the external purified gas valve group.

[0031] The methanol in the middle of the methanol washing tower is first flashed in flash tank 1, then flashed in flash tank 2, and the liquid phase enters the carbon dioxide decomposition tower through flash tank inlet decomposition tower valve 1. The methanol at the bottom of the methanol washing tower is first flashed in flash tank 3, then flashed in flash tank 4, and the liquid phase enters the carbon dioxide decomposition tower through flash tank inlet decomposition tower valve 2. The qualified flash gas (1.6Mpa) flashed out by the first-level flash module (flash tank 1 and flash tank 3) and the qualified flash gas (0.8Mpa) flashed out by the second-level flash module (flash tank 2 and flash tank 4) are pressurized (6.8Mpa) by the flash compression unit, and the compressed high-pressure flash gas is cooled by the circulating water heat exchanger and then sent to the conversion gas pipeline through the flash gas inlet system valve for reuse.

[0032] By adopting the above technical solution disclosed in the utility model, the following beneficial effects are obtained:

[0033] The utility model provides a methanol synthesis flash gas recovery and reuse device, which separates purified gas from methanol through a methanol scrubber, and the purified gas is then sent to synthesis after heat exchange, and the obtained crude methanol is flash-evaporated and purified through primary and secondary flash evaporation modules, and the flash gas generated during the flash evaporation process is collected in the system for reuse. The amount of methanol entrained in the flash gas is reduced, the loss of methanol with gas phase components is reduced, and the gas-liquid separation efficiency and methanol recovery rate are improved.

[0034] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be considered as the protection scope of the present invention.

Claims

1. A methanol synthesis flash gas recovery and recycling device, characterized in that: It includes a heat exchanger 1, a methanol washing tower, a heat exchanger 2, a valve group for sending purified gas, a primary flash evaporation module, a secondary flash evaporation module, a carbon dioxide analysis tower and a flash compression unit; the conversion gas delivered from the low-temperature methanol washing station is connected to the conversion gas input end of the heat exchanger 1 through a conversion gas pipeline, the conversion gas output end of the heat exchanger 1 is connected to the input end of the methanol washing tower, the top output end of the methanol washing tower is connected to the input end of the heat exchanger 2, the output end of the heat exchanger 2 is connected to the purified gas input end of the heat exchanger 1, and the purified gas output end of the heat exchanger 1 is connected to the valve group for sending purified gas; The middle output end and the bottom output end of the methanol washing tower are both connected to the first-level flash evaporation module, the liquid phase output end of the first-level flash evaporation module is connected to the input end of the second-level flash evaporation module, the liquid phase output end of the second-level flash evaporation module is connected to the carbon dioxide analysis tower, the gas phase output ends of the first-level flash evaporation module and the second-level flash evaporation module are connected to the input end of the flash compression unit, and the output end of the flash compression unit is connected to the conversion gas pipeline.

2. The methanol synthesis flash gas recovery and reuse device according to claim 1, characterized in that: The connecting pipeline between the heat exchanger 1 and the methanol washing tower is provided with a conversion gas inlet washing tower valve.

3. The methanol synthesis flash gas recovery and reuse device according to claim 1, characterized in that: The primary flash module includes a flash tank 1 and a flash tank 3. The middle output end and the bottom output end of the methanol washing tower are connected to the flash tank 1 and the flash tank 3 respectively. The liquid phase output ends of the flash tank 1 and the flash tank 3 are connected to the input end of the secondary flash tank; the gas phase output ends of the flash tank 1 and the flash tank 3 are connected to the input end of the flash compression unit.

4. The methanol synthesis flash gas recovery and reuse device according to claim 3, characterized in that: The gas phase output ends of the flash tank 1 and the flash tank 3 are connected to the input end of the flash compressor unit through a first-level flash gas inlet flash compressor pipeline; a first-level flash gas inlet flash compressor valve is arranged on the first-level flash gas inlet flash compressor pipeline.

5. The methanol synthesis flash gas recovery and reuse device according to claim 3, characterized in that: The secondary flash module includes a flash tank 2 and a flash tank 4, wherein the liquid phase output ends of the flash tank 1 and the flash tank 3 are respectively connected to the input ends of the flash tank 2 and the flash tank 4, the liquid phase output ends of the flash tank 2 and the flash tank 4 are connected to the carbon dioxide analysis tower, and the gas phase output ends of the flash tank 2 and the flash tank 4 are connected to the input end of the flash compression unit.

6. The methanol synthesis flash gas recovery and reuse device according to claim 5, characterized in that: The gas phase output ends of the flash tank 2 and the flash tank 4 are connected to the input end of the flash compressor unit through a secondary flash gas inlet flash compressor pipeline; a secondary flash gas inlet flash compressor valve is arranged on the secondary flash gas inlet flash compressor pipeline.

7. The methanol synthesis flash gas recovery and reuse device according to claim 5, characterized in that: The connecting pipe between the flash tank 2 and the carbon dioxide decomposition tower is provided with a first valve for the flash tank to enter the decomposition tower; the connecting pipe between the flash tank 4 and the carbon dioxide decomposition tower is provided with a second valve for the flash tank to enter the decomposition tower.

8. The methanol synthesis flash gas recovery and reuse device according to claim 1, characterized in that: A flash gas inlet system valve is provided on the connecting pipeline between the flash compression unit and the conversion gas pipeline.

9. The methanol synthesis flash gas recovery and reuse device according to claim 8, characterized in that: The flash compressor unit comprises four flash compressors connected in series.

10. The methanol synthesis flash gas recovery and reuse device according to claim 8, characterized in that: A circulating water heat exchanger is arranged in the cylinder of the flash compressor.