Hydrogen production facility put into operation
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Could someone with experience advise me on the differences between cold nitrogen and hot nitrogen cycles during the commissioning of a hydrogen production plant?
The hot nitrogen cycle is based on the cold nitrogen cycle; it is only initiated after everything is normal in the cold nitrogen cycle – such as the proper operation of the unit, no leaks in the equipment, and the heating furnace being ready for ignition – that is, once all these conditions are met, ignition takes place to start the hot nitrogen cycle.
After performing a cold nitrogen cycle, and once it is confirmed that the system compressor is operating properly, ignition is initiated to heat the furnace, after which hot nitrogen gas circulation begins.
The difference between cold nitrogen and hot nitrogen cycles during startup: The hot nitrogen cycle is used to assess the performance of the equipment under hot conditions, particularly the operation of the converter at high temperatures. It serves to prepare for the reduction of the catalyst in the converter during startup and to get everything ready for feeding material into the system. If a hot nitrogen cycle is used during furnace drying, it is best to introduce steam into the converter after the drying process is complete, in order to raise the temperature of the entire converter to its normal operating level and conduct tests under hot conditions, thereby gaining experience for actual material feeding.
For modern heating furnaces, fireproof and heat-insulating materials generally do not require a dedicated drying time.
(1) Cold nitrogen operation (after performing a gas-tightness check on the main process system, establishing a circulation in that system, and testing the performance of relevant equipment and instruments in a cold state)； (2) Hot nitrogen commissioning (with emphasis on the conversion furnace ignition procedure). Hot nitrogen operation: Purpose: To generate steam using the waste heat system and supply it to the main process system; the relevant operating conditions (temperature, pressure, flow rate, liquid level, etc.) should be as close as possible to those under normal operation, in order to simulate normal operating conditions and test the performance of all equipment and instruments ； The identified issues are also recorded in detail to facilitate corrective actions ；