FCC process with carbon monoxide management and hot stripping

摘要

The production of carbon monoxide as a combustion off-gas is maximized by the use of a hot stripping zone arrangement that provides catalyst mixing to establish a uniform catalyst temperature and thorough contacting of the well-mixed hot catalyst in a confined portion of the hot stripping zone. The hot stripping zone delivers the hot stripped catalyst to a bubbling-bed regeneration zone by an oxygen-starved lift stream that distributes the catalyst to the top of the bubbling-bed in the regeneration zone. The process delivers spent catalyst with about 1 wt % of coke to the reaction zone and a spent combustion gas or flue gas stream having a CO.sub.2 to CO ratio of at least 1. The operation reduces the heat evolution in the regeneration step and allows relatively low temperature operation of the regeneration zone without use of catalyst coolers.