What are the steps for heating and drying the catalyst as well as for pre-sulfiding the catalyst when a coal-to-hydrogen plant is brought online? Are there any things to keep in mind?

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Pre-vulcanization is intended to save costs, shorten the construction period, and eliminate the complicated process of vulcanization

1 Condition confirmation 1.1 Confirm that the system is in condition to start up. 1.2 Confirm the heating process in accordance with the operating procedures. 1.3 Verify that all indicators of the heating furnace are normal before starting operation. 2 Catalyst heating 2.1 Airtightness test passed. 2.2 Perform N2 purging in accordance with the operating procedures to ensure complete removal of air (an O2 content of less than 0.5% indicates that the system has been properly purged). 2.3 Set the nitrogen flow rate to introduce nitrogen into the system, controlling the pressure increase rate at ≤0.1 MPa/min; once the system pressure reaches 0.2–0.35 Mpa, adjust the nitrogen flow rate to above 5000 NM3/h. 2.4 Commission the start-up heating furnace. 2.5 Gradually increase the nitrogen flow rate to over 20,000 NM3/h. 2.6 Adjust the heating rate of nitrogen at the outlet of the startup furnace to ≤50°C/h, and the heating rate of the catalyst bed to ≤25°C/h, so that the temperature of the catalyst bed reaches ~120°C, and this temperature is maintained for 2 hours. 2.7 After the catalyst bed temperature reached ~120°C and was maintained at that level for 2 hours, the nitrogen temperature at the outlet of the startup heater was adjusted so that the catalyst bed temperature could rise to 150°C at a rate of 30°C/h. It was then raised at a rate of 25°C/h until the temperature at all points in the bed reached around 250°C–260°C, after which this temperature was maintained for 3 hours. Then proceed to the next gas guiding procedure. Note: Be sure to turn on the drain before introducing gas to completely discharge the condensate water. 3 Gas introduction for startup 3.1 After the bed temperature reaches 260°C and remains constant for 3 hours, the inlet temperature is adjusted to slowly introduce the feed gas for gas introduction. First, introduce process gas at a rate of 5000–10000 NM3/h, and appropriately reduce the nitrogen flow rate (it is also possible not to reduce it). Adjust the nitrogen temperature at the outlet of the startup heater to maintain the reactor inlet temperature above ~220°C. 3.2 Closely monitor the changes in bed temperature, and increase the process gas flow rate based on these changes. Keep the bed temperature stable, increase the flow rate of the process gas appropriately, while gradually reducing the nitrogen inlet flow; once the heat generated by the reaction is sufficient to maintain the inlet temperature, stop supplying nitrogen. 3.3 Continue to increase the flow rate of the process gas, while raising the inlet temperature and pressure, until all of the process gas is fed into the shift converter. 3.4 Adjust the inlet temperature and pressure to the design values. Precautions: 1. Analyze the oxygen content before raising the temperature to ensure complete air displacement. 2. The initial heating rate should not be too fast; the temperature should be maintained at 80–90°C for 3 hours, and at 120°C for 3 hours as well. 3. During the heating process, the temperature at hot spots must be strictly controlled to be below 280°C.