The development of FCC technology is closely dependent on the development of the catalyst. The catalytic cracking unit of the fluidized bed has been developed with the microsphere catalyst. The emergence of molecular sieve catalyst has developed the catalytic cracking of the riser, and the suitable catalyst has been selected for the product yield, product quality and economic benefit of the FCC process. Great impact. FCCU usually consists of three parts, namely, reaction regeneration system, fractionation system and absorption stabilization system. The reaction regeneration system is the core of the whole device.