A PSA analysis gas recovery system
By installing pressure gauges and controllers to control the reflux valve in the PSA system, and combining this with the heat exchanger to heat the desorbed gas, the problem of pipe narrowing caused by CO2 frosting in the desorbed gas was solved. This enabled the recovery of the desorbed gas and the stable operation of the system, thereby reducing production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- NEIMENGGU SANWEI COAL CHEM TECH CO LTD
- Filing Date
- 2025-08-28
- Publication Date
- 2026-07-24
AI Technical Summary
The trace amounts of CO2 in the PSA system's anneal gas result in a low freezing point. After prolonged operation, CO2 frosts up on the inner walls of the pipes, causing the pipes to narrow, the compressor back pressure to be high, and the anneal gas to be released, resulting in significant waste and increased production costs.
By installing a pressure gauge and controller between the desorbed gas compressor and the cryogenic separation system, the cryogenic reflux valve and the decarbonization reflux valve are controlled to ensure that the desorbed gas flows back to the decarbonization system. Combined with the heat exchanger to heat up the desorbed gas, frost formation is avoided and waste is reduced.
Effective recovery of desorbed gas reduces raw material gas consumption, lowers production costs, extends system uptime, and prevents compressor back pressure from rising due to pipeline frost.
Smart Images
Figure CN224551329U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of coal-to-ethylene glycol, specifically to a PSA desorbed gas recovery system. Background Technology
[0002] Coal-based ethylene glycol production uses coal-based syngas as raw material, employing an oxidative coupling reaction to produce dimethyl oxalate, which is then used to synthesize ethylene glycol. After decarbonization treatment, the crude coal gas undergoes cryogenic separation to remove carbon monoxide and prepare dimethyl oxalate. Hydrogen is then separated using a PSA (Pressure Swing Adsorption) system, and the dimethyl oxalate reacts with the hydrogen to ultimately produce ethylene glycol.
[0003] During production, the PSA system's stripper gas consists of 50% CO, 49.9% H2, and 0.1% CO2. After being pressurized by the stripper gas compressor, it is sent back to the hydrogen flash evaporator in the cryogenic separation system for hydrogen flash evaporation. This reduces the consumption of raw material gas and lowers the production costs of the raw material gas for the cryogenic separation system and PSA system. However, the PSA system stripper gas contains trace amounts of CO2 with a freezing point of -56.55℃. After prolonged operation, CO2 frosts on the inner wall of the stripper gas pipeline, causing the pipeline to narrow and the back pressure of the stripper gas compressor to be high. When adjusting the compressor outlet pressure, some stripper gas needs to be released to the flare for combustion to ensure the safety of the unit system, resulting in significant waste of stripper gas and increasing the production cost of ethylene glycol. Utility Model Content
[0004] The purpose of this invention is to provide a PSA desorption gas recovery system.
[0005] This utility model is implemented by the following technical solution: A PSA gas recovery system includes a decarbonization system, a cryogenic separation system, a PSA system, and a carbonylation reactor; The inlet of the decarbonization system is connected to the crude coal gas pipe, the outlet of the decarbonization system is connected to the inlet of the cryogenic separation system, the carbon monoxide outlet of the cryogenic separation system is connected to the inlet of the carbonylation reactor, the hydrogen outlet of the cryogenic separation system is connected to the inlet of the PSA system, the hydrogen outlet of the PSA system is connected to the hydrogen pipe, the desorbed gas outlet of the PSA system is connected to the inlet of the desorbed gas compressor, the outlet of the desorbed gas compressor is connected to the reflux gas inlet of the cryogenic separation system, and the outlet of the desorbed gas compressor is also connected to the inlet of the decarbonization system through a decarbonization reflux pipe. A pressure gauge is installed at the reflux gas inlet of the cryogenic separation system. A cryogenic reflux valve is installed on the pipeline between the desorbed gas compressor and the cryogenic separation system. A decarbonization reflux valve is installed on the decarbonization reflux pipe. The signal output terminal of the pressure gauge is electrically connected to the signal input terminal of the controller. The signal output terminal of the controller is electrically connected to the signal input terminals of the cryogenic reflux valve and the decarbonization reflux valve.
[0006] Preferably, it also includes a heat exchanger, wherein the outlet of the decarbonization system is connected to the heat source inlet of the heat exchanger, and the heat source outlet of the heat exchanger is connected to the inlet of the cryogenic separation system. The outlet of the desorbed gas compressor is connected to the cold source inlet of the heat exchanger, and the cold source outlet of the heat exchanger is connected to the return gas inlet of the cryogenic separation system.
[0007] Preferably, the outlet of the desorbed gas compressor is also connected to a vent pipe, and a vent valve is installed on the vent pipe.
[0008] Advantages of this utility model: The pressure of the desorbed gas returning to the cryogenic separation system is monitored by a pressure gauge. The opening and closing of the cryogenic reflux valve and the decarbonization reflux valve are controlled to ensure that the desorbed gas is returned to the decarbonization system through the decarbonization reflux valve when the reflux gas inlet of the cryogenic separation system narrows. This ensures that the desorbed gas can be returned to the system for recovery, reducing the waste of raw material gas. The raw material gas is used to heat the desorbed gas, preventing CO2 from rapidly frosting on the inner wall of the desorbed gas pipeline. This ensures that the narrowing of the desorbed gas pipeline due to frosting is slower, increasing the system's normal operating time. Attached Figure Description
[0009] Figure 1 This is a schematic diagram of the structure of this utility model.
[0010] In the diagram: 1. Decarbonization system; 2. Cryogenic separation system; 3. PSA system; 4. Carbonylation reactor; 5. Crude gas pipe; 6. Decarbonization gas compressor; 7. Decarbonization reflux pipe; 8. Pressure gauge; 9. Cryogenic reflux valve; 10. Decarbonization reflux valve; 11. Heat exchanger; 12. Vent pipe; 13. Vent valve. Detailed Implementation
[0011] like Figure 1 As shown, a PSA desorbed gas recovery system includes a decarbonization system 1, a cryogenic separation system 2, a PSA system 3, and a carbonylation reactor 4; The inlet of the decarbonization system 1 is connected to the crude gas pipe 5, the outlet of the decarbonization system 1 is connected to the inlet of the cryogenic separation system 2, the carbon monoxide outlet of the cryogenic separation system 2 is connected to the inlet of the carbonylation reactor 4, the hydrogen outlet of the cryogenic separation system 2 is connected to the inlet of the PSA system 3, the hydrogen outlet of the PSA system 3 is connected to the hydrogen pipe, the desorbed gas outlet of the PSA system 3 is connected to the inlet of the desorbed gas compressor 6, the outlet of the desorbed gas compressor 6 is connected to the reflux gas inlet of the cryogenic separation system 2, and the outlet of the desorbed gas compressor 6 is also connected to the inlet of the decarbonization system 1 through the decarbonization reflux pipe 7. A pressure gauge 8 is installed at the reflux gas inlet of the cryogenic separation system 2. A cryogenic reflux valve 9 is installed on the pipeline between the desorbed gas compressor 6 and the cryogenic separation system 2. A decarbonization reflux valve 10 is installed on the decarbonization reflux pipe 7. The signal output terminal of the pressure gauge 8 is electrically connected to the signal input terminal of the controller. The signal output terminal of the controller is electrically connected to the signal input terminals of the cryogenic reflux valve 9 and the decarbonization reflux valve 10. The raw gas enters the decarbonization system 1 through the crude gas pipe 5 to separate some of the carbon dioxide. The decarbonized raw gas is then sent to the cryogenic separation system 2 to separate carbon monoxide and hydrogen. The carbon monoxide is sent to the carbonylation reactor 4 to synthesize dimethyl oxalate, while the hydrogen is sent to the PSA system 3 for purification. The cryogenic reflux valve 9 is in the open state. The desorbed gas in the PSA system 3 is pressurized by the desorbed gas compressor 6 and then sent back to the cryogenic separation system 2 for recovery. Pressure gauge 8 is used to detect the pressure of the desorbed gas returning to the cryogenic separation system 2 and sends the signal back to the controller. When the pressure value detected by pressure gauge 8 is greater than 1MPa, the controller controls the cryogenic reflux valve 9 to close and the decarbonization reflux valve 10 to open. The desorbed gas is sent back to the decarbonization system 1 through the decarbonization reflux valve 10 to ensure that the desorbed gas can be returned to the system for recovery. At the same time, the reflux gas inlet of the cryogenic separation system 2 is inspected and cleaned. After maintenance, the desorbed gas is switched back to the reflux gas inlet of the cryogenic separation system 2.
[0012] It also includes a heat exchanger 11, with the outlet of the decarbonization system 1 connected to the heat source inlet of the heat exchanger 11, and the heat source outlet of the heat exchanger 11 connected to the inlet of the cryogenic separation system 2; the outlet of the desorbed gas compressor 6 is connected to the cold source inlet of the heat exchanger 11, and the cold source outlet of the heat exchanger 11 is connected to the return gas inlet of the cryogenic separation system 2. The desorbed gas temperature is 22°C, and the raw material gas temperature is 30°C. The raw material gas is used to heat the desorbed gas, preventing CO2 from rapidly frosting on the inner wall of the desorbed gas pipeline, ensuring that the desorbed gas pipeline narrows more slowly due to frosting, and improving the normal operating time of the system.
[0013] The outlet of the desorbed gas compressor 6 is also connected to the vent pipe 12. A vent valve 13 is installed on the vent pipe 12. If the pipelines from the desorbed gas to the decarbonization system 1 and the cryogenic separation system 2 both fail, the vent valve 13 is opened to release the desorbed gas.
[0014] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A PSA desorbed gas recovery system, characterized in that, This includes a decarbonization system, a cryogenic separation system, a PSA system, and a carbonylation reactor; The inlet of the decarbonization system is connected to the crude coal gas pipe, the outlet of the decarbonization system is connected to the inlet of the cryogenic separation system, the carbon monoxide outlet of the cryogenic separation system is connected to the inlet of the carbonylation reactor, the hydrogen outlet of the cryogenic separation system is connected to the inlet of the PSA system, the hydrogen outlet of the PSA system is connected to the hydrogen pipe, the desorbed gas outlet of the PSA system is connected to the inlet of the desorbed gas compressor, the outlet of the desorbed gas compressor is connected to the reflux gas inlet of the cryogenic separation system, and the outlet of the desorbed gas compressor is also connected to the inlet of the decarbonization system through a decarbonization reflux pipe. A pressure gauge is installed at the reflux gas inlet of the cryogenic separation system. A cryogenic reflux valve is installed on the pipeline between the desorbed gas compressor and the cryogenic separation system. A decarbonization reflux valve is installed on the decarbonization reflux pipe. The signal output terminal of the pressure gauge is electrically connected to the signal input terminal of the controller. The signal output terminal of the controller is electrically connected to the signal input terminals of the cryogenic reflux valve and the decarbonization reflux valve.
2. The PSA desorbed gas recovery system according to claim 1, characterized in that, It also includes a heat exchanger, wherein the outlet of the decarbonization system is connected to the heat source inlet of the heat exchanger, and the heat source outlet of the heat exchanger is connected to the inlet of the cryogenic separation system. The outlet of the desorbed gas compressor is connected to the cold source inlet of the heat exchanger, and the cold source outlet of the heat exchanger is connected to the return gas inlet of the cryogenic separation system.
3. The PSA desorbed gas recovery system according to claim 1, characterized in that, The outlet of the desorbed gas compressor is also connected to a vent pipe, and a vent valve is installed on the vent pipe.