Shutdown of methanol-to-hydrogen production, catalyst reduction and passivation steps, temperature changes during reduction and passivation, and precautions
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Shutdown of methanol-to-hydrogen production, catalyst reduction and passivation steps, temperature changes during reduction and passivation, as well as precautions. Changes in air distribution temperature during reduction
I have this process: one methanol molecule produces 3 hydrogen molecules. . . . I’ve forgotten how many cubic meters it is exactly; it’s been many years since I calculated it. At that time, we had 120 cubic meters of catalyst, and 75 cubic meters were used for catalyst vulcanization; the total amount of methanol required for hydrogen production via cracking seemed to be 35 tons. The overall reaction is CH3OH + H2O = CO2 + 3H2. That’s it. Methanol cracking is accompanied by a shift reaction as well
In methanol-to-hydrogen plants, catalyst passivation is generally not carried out when the shutdown time is short; instead, the system is simply purged with nitrogen to maintain pressure. If the shutdown lasts for an extended period, purified air is mixed with nitrogen for oxidative passivation, with the temperature kept below 200°C. The purified air is introduced slowly as well, and the temperature of the reactor bed remains below 200°C. The specific temperature values should be provided by the catalyst manufacturer. The reduction process is similar, only with hydrogen used as the medium.