Natural gas-based hydrogen production converters: precautions regarding catalyst coking during startup and shutdown

During the startup and shutdown of natural gas-based hydrogen production converters, the following measures can be taken to avoid catalyst coking: 1. **Temperature control**: Strictly control the temperature of the reactor, especially during startup and shutdown phases. Avoid catalyst pyrolysis or coking caused by excessive temperatures. 2. **Slow heating and cooling**: During startup and shutdown, the temperature should be adjusted gradually to prevent coking caused by rapid temperature changes. 3. **Purity management**: Ensure the purity of the feed materials to prevent gases containing impurities such as sulfur and nitrogen from entering the reactor; these impurities can easily cause carbon deposition on the surface of the catalyst. 4. **Gas flow control**: Maintain an adequate gas flow rate to prevent coking in certain areas due to stagnant gas. 5. **Pre-treatment system**: Enhance the pre-treatment system for raw gas, such as desulfurization and drying, to reduce potential coking sources entering the reactor. 6. **Regular inspection and maintenance**: Periodically inspect the conversion furnace and carry out necessary maintenance to promptly detect and address any abnormalities in the catalyst. Through the above measures, the risk of catalyst coking during startup and shutdown periods can be effectively reduced, the service life of the catalyst can be extended, and the safe and stable operation of the converter can be ensured. .

Before feeding: (1) Ensure that the catalyst has sufficient activity (check the catalyst’s instructions or consult the catalyst manufacturer to determine whether feeding is possible directly); if possible, introduce hydrogen immediately after feeding. (2) Ensure that the temperature for the hydrodesulfurization reaction is within the appropriate range. (3) Analyze the raw material to prevent the entry of high-molecular-weight components into the conversion process. (4) Maintain a high water-to-carbon ratio, and ensure that the steam flow rate is accurate； Incorrect operation during vapor distribution (5): Ensure the burners are ignited as evenly as possible, in a plum blossom pattern ； Low flame intensity; no addition of furnace tubes. During shutdown: (1) Reduce temperature, flow rate, and steam supply, while keeping the temperature under control; maintain a high water-to-carbon ratio. (2) If using a hot nitrogen cycle, make sure to replace the gas first to reduce hydrogen purity, before establishing the circulation for cooling. (3) Pay attention to controlling the burners and flames; do not add furnace tubes