Abstract: The semi-regenerative standpipe is used for conveying catalyst between stacked two-stage regenerator in the FCC unit. Abnormal catalyst transportation occurred in standpipe during operation, which directly affected the unit operation and catalyst regeneration efficiency. Based on the analysis of the pressure balance of particle circulation loop, the cause is being the obstacle in inlet feed and outlet discharge, resulting in not enough driven force in the pipe for catalyst downward. By optimizing the fluxes of particle feed and discharge and controlling the loosen wind rate, the capacity of the catalyst transportation in standpipe can be effectively improved.

Key words: FCC, semi-regenerative standpipe, transportation, fault, analysis