Methanol-to-hydrogen production shut down
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Is it necessary to purge the cracking reactor with nitrogen when the methanol-to-hydrogen plant is shut down? If necessary, what is the standard for replacement?
I don’t understand what is being meant – what is the relationship between methanol-based hydrogen production and cracking reactions?
When the reactor is not in use for an extended period, it needs to be purged with nitrogen, mainly to protect the catalyst. Release hydrogen and then use nitrogen to maintain the system pressure at 0.3 MPa, right? Hydrogen can be used to protect the catalyst in the short term, without the need for displacement.
For long-term parking, close the valves at the inlet to the converter and at the outlet of the converter; set the nitrogen pressure to 0. 11~0. 12MPA is used to fill the converter with nitrogen; the reaction gas displaced is released from the top of the vapor-liquid separator, thereby reducing the pressure and temperature in the system. When the volume of gas displaced reaches around 2 m3, the exhaust valve is closed to seal the reaction system. Always keep the converter at positive pressure.
Thank you. I’ve learned it.* What is the indicator that the replacement is complete? Are there any requirements for the components to be sampled and analyzed during replacement?
Nitrogen protection serves to passivate the catalyst, and a nitrogen pressure of 2–4 bar inside the converter is sufficient.
It mainly involves displacing the easily liquefiable components inside the reactor. Catalysts for hydrogen production from methanol are afraid of liquids!
In the first half of the year, I learned at a company about the shutdown procedures related to hydrogen production from methanol. After production stopped on their end and the reactor cooled down, the mixed materials remained inside the reactor; it would have been expected that this could cause the catalyst to become powdered or suffer some other damage, but their catalyst was not affected at all. The catalyst is BQCH-01
The acceptable standard for oxygen content in replacement gas is less than 200PPM