Methanol Purification Version – Daily Question 20200923

a. Upon receiving the stop command, inform the compressor operator to supply fresh gas, and at the same time open the anti-surge valves for stages 1 and 2 fully to ensure sufficient flow at the compressor inlet and prevent surge. Stop the high-pressure steam to the desulfurization reactor. b. The compressor and reactor continue to operate in a linked cycle; the system pressure is controlled through the system vent valve (PV2052), with the pressure being reduced at a rate of ≤0.1 MPa/min until it reaches 0.5–0.8 MPa. c. Control the drum pressure properly to maintain the catalyst layer temperature above its active temperature, and reduce the CO and CO2 levels in the recycled gas to CO+CO2 ≤ 0.2%. d. When the liquid level in the high-pressure separator reaches 5–10%, close the high-pressure separator level control valve (LV2051) as well as the inlet and outlet isolation valves. When the liquid level in the low-pressure separator reaches 5–10%, close the low-pressure separator level control valve (LV2057) as well as the upstream and downstream isolation valves. Close the isolation valve before shutting down the flash vapor main valve (PV2057). e. When the temperature of the catalyst layer drops below the active temperature, the reactor is cooled at a rate of ≤25 ℃/h. Close the main steam outlet valve of the drum (PV2027A) to stop the steam output, and open the steam vent valve (PV2027B). When the temperature of the catalyst layer drops to 100°C, close the feed water valve (FV2031) on the steam drum as well as the inlet and outlet isolation valves, thereby stopping the supply of water to the steam drum. f. Open the nitrogen filling valve at the compressor inlet to purge the entire system with nitrogen; close this valve once CO + H2 is below 0.5%. g. When the temperature of the catalyst layer drops below 80°C, stop the compressor and close the main valve at the compressor outlet as well as the main valve at the inlet for the circulating gas ； Circulating water of the water cooler ； Close the bleed flow control valve (FV2053) as well as the upstream and downstream isolation valves; the system shall be maintained at a pressure of 0.5–0.8 MPa.

Note: 1. Drain all the liquid ammonia from the ammonia cooler. 2. Prevent pressure buildup and surge at the outlet of the syngas compressor. 3. Pay attention to the chiller pressure. 4. The pressure release in the synthesis tower should be done slowly; it cannot be too fast. 5. Pressure retention cycle regeneration of the decarburization system. 6. Purge the conversion system with N2 and maintain a pressure of 2.0--3.0 MPa, being careful to drain water.

Note: 1. Drain all the liquid ammonia from the ammonia cooler. 2. Prevent pressure buildup and surge at the outlet of the syngas compressor. 3. Pay attention to the chiller pressure. 4. The pressure release in the synthesis tower should be done slowly; it cannot be too fast. 5. Pressure retention cycle regeneration of the decarburization system. 6. Purge the conversion system with N2 and maintain a pressure of 2.0--3.0 MPa, being careful to drain water.

Note: 1. Drain all the liquid ammonia from the ammonia cooler. 2. Prevent pressure buildup and surge at the outlet of the syngas compressor. 3. Pay attention to the chiller pressure. 4. The pressure release in the synthesis tower should be done slowly; it cannot be too fast. 5. Pressure retention cycle regeneration of the decarburization system. 6. Purge the conversion system with N2 and maintain a pressure of 2.0--3.0 MPa, being careful to drain water.

a. Upon receiving the stop command, inform the compressor operator to supply fresh gas, and at the same time open the anti-surge valves for stages 1 and 2 fully to ensure sufficient flow at the compressor inlet and prevent surge. Stop the high-pressure steam to the desulfurization reactor. b. The compressor and reactor continue to operate in a coupled cycle; the system pressure is controlled through the system vent valve (PV2052), with the pressure being reduced at a rate of ≤0.1 MPa/min until it reaches 0.5–0.8 MPa. c. Control the drum pressure properly to maintain the catalyst layer temperature above its active temperature, and reduce the CO and CO2 levels in the recycled gas to such an extent that CO + CO2 ≤ 0.2%. ??d. When the liquid level in the high-pressure separator reaches 5–10%, close the high-pressure separator level control valve (LV2051) as well as the upstream and downstream isolation valves. When the liquid level in the low-pressure separator reaches 5–10%, close the low-pressure separator level control valve (LV2057) as well as the upstream and downstream isolation valves. Close the isolation valve before shutting down the flash vapor main valve (PV2057). ? ?e. When the temperature of the catalyst layer drops below the active temperature, the reactor is cooled at a rate of ≤25 ℃/h. Close the main steam outlet valve of the drum (PV2027A) to stop the steam output, and open the steam vent valve (PV2027B). When the temperature of the catalyst layer drops to 100°C, close the feed water valve (FV2031) on the steam drum as well as the inlet and outlet isolation valves, thereby stopping the supply of water to the steam drum. ??f. Open the nitrogen filling valve at the compressor inlet to purge the entire system with nitrogen; close this valve once CO + H2 is below 0.5%. ??g. When the temperature of the catalyst layer drops below 80°C, stop the compressor and close the main valve at the compressor outlet as well as the main valve at the inlet for the circulating gas ； Circulating water of the water cooler ； Close the bleed flow control valve (FV2053) as well as the upstream and downstream isolation valves; the system shall be maintained at a pressure of 0.5–0.8 MPa.

a. Upon receiving the stop command, inform the compressor operator to supply fresh gas, and at the same time open the anti-surge valves for stages 1 and 2 fully to ensure sufficient flow at the compressor inlet and prevent surge. Stop the high-pressure steam to the desulfurization reactor. b. The compressor and reactor continue to operate in a linked cycle; the system pressure is controlled through the system vent valve (PV2052), with the pressure being reduced at a rate of ≤0.1 MPa/min until it reaches 0.5–0.8 MPa. c. Control the drum pressure properly to maintain the catalyst layer temperature above its active temperature, and reduce the CO and CO2 levels in the recycled gas to CO+CO2 ≤ 0.2%. d. When the liquid level in the high-pressure separator reaches 5–10%, close the high-pressure separator level control valve (LV2051) as well as the inlet and outlet isolation valves. When the liquid level in the low-pressure separator reaches 5–10%, close the low-pressure separator level control valve (LV2057) as well as the upstream and downstream isolation valves. Close the isolation valve before shutting down the flash vapor main valve (PV2057). e. When the temperature of the catalyst layer drops below the active temperature, the reactor is cooled at a rate of ≤25 ℃/h. Close the main steam outlet valve of the drum (PV2027A) to stop the steam output, and open the steam vent valve (PV2027B). When the temperature of the catalyst layer drops to 100°C, close the feed water valve (FV2031) on the steam drum as well as the inlet and outlet isolation valves, thereby stopping the supply of water to the steam drum. f. Open the nitrogen filling valve at the compressor inlet to purge the entire system with nitrogen; close this valve once CO + H2 is below 0.5%. g. When the temperature of the catalyst layer drops below 80°C, stop the compressor and close the main valve at the compressor outlet as well as the main valve at the inlet for the circulating gas ； Circulating water of the water cooler ； Close the bleed flow control valve (FV2053) as well as the upstream and downstream isolation valves; the system shall be maintained at a pressure of 0.5–0.8 MPa.

1. Drain the liquid ammonia from the ammonia cooler. 2. Prevent pressure buildup and surge at the outlet of the syngas compressor. 3. Pay attention to the chiller pressure. 4. The pressure release in the synthesis tower should be done slowly; it cannot be too fast. 5. Pressure retention cycle regeneration of the decarburization system. 6. Purge the conversion system with N2 and maintain a pressure of 2.0--3.0 MPa, being careful to drain water.

Note: 1. Drain all the liquid ammonia from the ammonia cooler. 2. Prevent pressure buildup and surge at the outlet of the syngas compressor. 3. Pay attention to the chiller pressure. 4. The pressure release in the synthesis tower should be done slowly; it cannot be too fast. 5. Pressure retention cycle regeneration of the decarburization system. 6. Purge the conversion system with N2 and maintain a pressure of 2.0--3.0 MPa, being careful to drain water.

Note: 1. Drain all the liquid ammonia from the ammonia cooler. 2. Prevent pressure buildup and surge at the outlet of the syngas compressor. 3. Pay attention to the chiller pressure. 4. The pressure release in the synthesis tower should be done slowly; it cannot be too fast. 5. Pressure retention cycle regeneration of the decarburization system. 6. Purge the conversion system with N2 and maintain a pressure of 2.0--3.0 MPa, being careful to drain water.

a. Upon receiving the stop command, inform the compressor operator to supply fresh gas, and at the same time open the anti-surge valves for stages 1 and 2 fully to ensure sufficient flow at the compressor inlet and prevent surge. Stop the high-pressure steam to the desulfurization reactor. b. The compressor and reactor continue to operate in a coupled cycle; the system pressure is controlled through the system vent valve (PV2052), with the pressure being reduced at a rate of ≤0.1 MPa/min until it reaches 0.5–0.8 MPa. c. Control the drum pressure properly to maintain the catalyst layer temperature above its active temperature, and reduce the CO and CO2 levels in the recycled gas to such an extent that CO + CO2 ≤ 0.2%. ??d. When the liquid level in the high-pressure separator reaches 5–10%, close the high-pressure separator level control valve (LV2051) as well as the upstream and downstream isolation valves. When the liquid level in the low-pressure separator reaches 5–10%, close the low-pressure separator level control valve (LV2057) as well as the upstream and downstream isolation valves. Close the isolation valve before shutting down the flash vapor main valve (PV2057). ? ?e. When the temperature of the catalyst layer drops below the active temperature, the reactor is cooled at a rate of ≤25 ℃/h. Close the main steam outlet valve of the drum (PV2027A) to stop the steam output, and open the steam vent valve (PV2027B). When the temperature of the catalyst layer drops to 100°C, close the feed water valve (FV2031) on the steam drum as well as the inlet and outlet isolation valves, thereby stopping the supply of water to the steam drum. ??f. Open the nitrogen filling valve at the compressor inlet to purge the entire system with nitrogen; close this valve once CO + H2 is below 0.5%. ??g. When the temperature of the catalyst layer drops below 80°C, stop the compressor and close the main valve at the compressor outlet as well as the main valve at the inlet for the circulating gas ； Circulating water of the water cooler ； Close the bleed flow control valve (FV2053) as well as the upstream and downstream isolation valves; the system shall be maintained at a pressure of 0.5–0.8 MPa.