Abstract: 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.

Abstract: 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.

Abstract: A method is provided herein for the extraction of phenol from a waste water stream. The method is used in conjunction with a process for producing acetone and phenol from cumene. The method for extracting phenol from waste water includes contacting in a countercurrent mode a phenol-containing waste water stream with a hydrocarbon stream derived from a bottoms stream from the acetone finishing column to produce a dephenolated waste water stream and a phenol-containing hydrocarbon stream. The phenol-containing hydrocarbon stream is preferably washed with an aqueous caustic solution to provide a hydrocarbon stream, which is then conveyed to the alpha-methylstyrene recovery system. Preferably the hydrocarbon stream derived from the bottoms stream of the acetone finishing column is water washed prior to contacting the phenol-containing waste water stream.

Abstract: A method is provided herein for the extraction of phenol from a waste water stream. The method is used in conjunction with a process for producing acetone and phenol from cumene. The method for extracting phenol from waste water includes contacting in a countercurrent mode a phenol-containing waste water stream with a hydrocarbon stream derived from a bottoms stream from the acetone finishing column to produce a dephenolated waste water stream and a phenol-containing hydrocarbon stream. The phenol-containing hydrocarbon stream is preferably washed with an aqueous caustic solution to provide a hydrocarbon stream, which is then conveyed to the alpha-methylstyrene recovery system. Preferably the hydrocarbon stream derived from the bottoms stream of the acetone finishing column is water washed prior to contacting the phenol-containing waste water stream.