Temperature of the medium-pressure reactor
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Take a look at the start-up and shutdown procedures for the dry gas hydrogen production unit. In both the start-up and shutdown procedures, for example during start-up, it is required that the temperature of the medium-pressure reactor be raised to 230°C and held at that level for a certain period of time. During shutdown, the temperature at the exit of the converter will reach 320°C, while the temperature at the exit of the medium-pressure reaction bed will be 230°C; at this point, steam supply to the converter is stopped. I’m not sure what the purpose of this 230°C control point is
In fact, during startup and shutdown, the system pressure is 0.6 MPa; the steam temperature must be above 230°C to remain in a gaseous state. If it’s water, the catalyst will be damaged, so it’s sufficient to maintain a temperature of over 200°C.
Whether the plant is operating or shut down, the minimum bed temperature must be 30°C above the steam dew point.
Ask the manufacturer and check your design to determine whether it involves high-temperature shift, medium-temperature shift, or low-temperature shift, as well as the heat balance when your facility is operating normally
Whenever considering the dew point temperature of steam at operating pressure, it must be kept about 30 degrees higher than that dew point temperature to prevent the formation of liquid water, which could damage the catalyst!
Above the steam leakage temperature, to protect the catalyst
In practice, we reduce the outlet temperature to 550°C and then stop supplying steam while continuing to burn gas; the system is subsequently purged with nitrogen. It is very difficult to lower the medium-temperature stage temperature to below 230°C in a short time. At the start of operation, we supply steam when the medium-temperature stage temperature is above 170°C. Initially, as the steam temperature rises, the medium-temperature stage temperature increases rapidly as well, so it is also challenging to maintain a constant temperature of 230°C. We produce hydrogen from natural gas; I’m not sure what the differences are between this process and producing hydrogen from dry gas
The control temperature must not be lower than the dew point temperature of the steam; water content can cause severe damage to the catalyst. This is basic information – read more books; this one is quite good.