Methanol Purification Version – Daily Question 20200514

It is necessary to control the heating rate and water outlet rate, as well as the pressure increase rate at the end stage

Care should be taken when reducing copper-based catalysts, and the reduction procedures must be strictly followed. Key operating principles: Three lows: low-temperature water output ； Low-hydrogen reduction ； There is a low-load operation period after the reduction is complete. Three stabilities: stable temperature rise, stable hydrogen supplementation, and stable water output. Three no’s: Hydrogen introduction and temperature increase should not occur simultaneously; moisture must not be introduced into the tower, and the time during which water is at high temperature should not be too long.

1) During the reduction process, it is necessary to closely monitor the changes in the temperature at the outlet of the synthesis tower; when the temperature rises sharply, it is essential to immediately stop or reduce the amount of reducing gas supplied, as well as decrease the flow rate of the steam nozzle. 2) Strictly control the effluent rate; the hourly water output shall not exceed 2 Kg per ton of catalyst. 3) Determination of the reduction endpoint: a. The concentration of CO+H2 in the gas exiting the reactor, as determined through multiple analyses, is consistent with the concentration at the inlet ； b. The separator level no longer rises. 4) After the reduction is complete, reduce the system pressure to 0.15 Mpa, maintain the temperature of the synthesis tower at no less than 210°C, and replace the N2 in the system with fresh gas until the N2 content is below 1%, after which methanol synthesis can be started. 5) When pressurizing with syngas, the pressure increase rate must not exceed 0.5 MPa/h to prevent excessive temperature rise that could damage the catalyst. 6) The operation of the new catalyst involves maintaining a certain production level, then gradually increasing the pressure to raise the circulation rate, increase the CO content, and gradually raise the temperature. During the first startup of the new catalyst, the exit temperature of the synthesis tower gradually increased from 220°C to 230°C. 7) The sulfur content and chloride content in the syngas should both be less than 0.1 PPm; trace amounts of oxygen, heavy metals, water vapor, and carbonyl compounds must not be introduced into the tower. 8) During the methanol synthesis process, the conditions must be strictly controlled; the temperature of the catalyst bed should not drop below 210°C. Sudden changes in catalyst temperature are strictly prohibited, and an optimal space velocity for the catalyst is 6000–10000 h-1. 9) In the event of a stoppage during operation, for short-term stops within 24 hours, the fresh gas supply can be cut off and circulation can continue until the reaction of CO+CO2 in the system is complete, keeping the catalyst bed temperature above 210°C. 10) If the parking time exceeds 24 hours, the normal procedure can be followed: after parking as described in (9), reduce the pressure and temperature, replace the air with N2, and maintain the system pressure at 0.5 MPa.

It is necessary to control the heating rate and water outlet rate, as well as the pressure increase rate at the end stage

1) During the reduction process, it is necessary to closely monitor the changes in the temperature at the outlet of the synthesis tower; when the temperature rises sharply, it is essential to immediately stop or reduce the amount of reducing gas supplied, as well as decrease the flow rate of the steam nozzle. 2) Strictly control the effluent rate; the hourly water output shall not exceed 2 Kg per ton of catalyst. 3) Determination of the reduction endpoint: a. The concentration of CO+H2 in the gas exiting the reactor, as determined through multiple analyses, is consistent with the concentration at the inlet ； b. The separator level no longer rises. 4) After the reduction is complete, reduce the system pressure to 0.15 Mpa, maintain the temperature of the synthesis tower at no less than 210°C, and replace the N2 in the system with fresh gas until the N2 content is below 1%, after which methanol synthesis can be started. 5) When pressurizing with syngas, the pressure increase rate must not exceed 0.5 MPa/h to prevent excessive temperature rise that could damage the catalyst. 6) The operation of the new catalyst involves maintaining a certain production level, then gradually increasing the pressure to raise the circulation rate, increase the CO content, and gradually raise the temperature. During the first startup of the new catalyst, the exit temperature of the synthesis tower gradually increased from 220°C to 230°C. 7) The sulfur content and chloride content in the syngas should both be less than 0.1 PPm; trace amounts of oxygen, heavy metals, water vapor, and carbonyl compounds must not be introduced into the tower. 8) During the methanol synthesis process, the conditions must be strictly controlled; the temperature of the catalyst bed should not drop below 210°C. Sudden changes in catalyst temperature are strictly prohibited, and an optimal space velocity for the catalyst is 6000–10000 h-1. 9) In the event of a stoppage during operation, for short-term stops within 24 hours, the fresh gas supply can be cut off and circulation can continue until the reaction of CO+CO2 in the system is complete, keeping the catalyst bed temperature above 210°C. 10) If the parking time exceeds 24 hours, the normal procedure can be followed: after parking as described in (9), reduce the pressure and temperature, replace the air with N2, and maintain the system pressure at 0.5 MPa.

Care should be taken when reducing copper-based catalysts, and the reduction procedures must be strictly followed. Key operating principles: Three lows: low-temperature water output ； Low-hydrogen reduction ； There is a low-load operation period after the reduction is complete. Three stabilities: stable temperature rise, stable hydrogen supplementation, and stable water output. Three no’s: Hydrogen introduction and temperature increase should not occur simultaneously; moisture must not be introduced into the tower, and the time during which water is at high temperature should not be too long

Care should be taken when reducing copper-based catalysts, and the reduction procedures must be strictly followed. Key operating principles: Three lows: low-temperature water output ； Low-hydrogen reduction ； There is a low-load operation period after the reduction is complete. Three stabilities: stable temperature rise, stable hydrogen supplementation, and stable water output. Three no’s: Hydrogen introduction and temperature increase should not occur simultaneously; moisture must not be introduced into the tower, and the time during which water is at high temperature should not be too long

Care should be taken when reducing copper-based catalysts, and the reduction procedures must be strictly followed. Key operating principles: Three lows: low-temperature water output ； Low-hydrogen reduction ； There is a low-load operation period after the reduction is complete. Three stabilities: stable temperature rise, stable hydrogen supplementation, and stable water output. Three no’s: Hydrogen introduction and temperature increase should not occur simultaneously; moisture must not be introduced into the tower, and the time during which water is at high temperature should not be too long.

Answer: Care should be taken when reducing copper-based catalysts, and the reduction procedures must be strictly followed. Key operating principles: Three lows: low-temperature water output ； Low-hydrogen reduction ； There is a low-load operation period after the reduction is complete. Three stabilities: stable temperature rise, stable hydrogen supplementation, and stable water output. Three no’s: Hydrogen introduction and temperature increase should not occur simultaneously; moisture must not be introduced into the tower, and the time during which water is at high temperature should not be too long.