METHOD OF SHUTTING DOWN A REACTOR

摘要

A procedure for shutting down a dehydrogenation reactor having a catalyst bed with a chromium-containing catalyst operating at a first elevated temperature comprises cooling the catalyst bed with a first cooling gas to a second elevated temperature lower than the first elevated temperature, removing the first cooling gas, introducing a reducing gas to the catalyst bed, cooling the catalyst bed with a second cooling gas from the second elevated temperature to a third elevated temperature, removing the reducing gas, cooling the catalyst bed to a fourth elevated temperature, and introducing air to cool the catalyst to ambient temperature, whereby the dehydrogenation reactor is shut down. The second cooling gas may be the same as, or different from, the reducing gas. Moreover, the reducing gas may be purged from the reactor by a third cooling gas.

主权项

1. A method of shutting down a dehydrogenation reactor, the dehydrogenation reactor housing a catalyst bed containing a chromium-containing catalyst, the catalyst bed operating at a first elevated temperature under standard dehydrogenation conditions, the method comprising:
(a) cooling the catalyst bed with a first cooling gas from the first elevated temperature to a second elevated temperature lower than the first elevated temperature; (b) removing the first cooling gas from the catalyst bed while maintaining the catalyst bed at about said second elevated temperature; (c) treating the catalyst bed with a reducing gas for a period of time sufficient to cause chemical reduction of at least some of the chromium in the catalyst to a reduced oxidation state; (d) cooling the catalyst bed with a second cooling gas from the second elevated temperature to a third elevated temperature lower than the second elevated temperature; (e) removing the reducing gas from the catalyst bed; (f) cooling the catalyst bed with a third cooling gas from the third elevated temperature to a fourth elevated temperature lower than the third elevated temperature; and (g) cooling the catalyst bed with a fourth cooling gas from the fourth elevated temperature to ambient temperature, whereupon the reactor is shut down, and wherein at least some of the chromium in the catalyst is at the reduced oxidation state.