Abstract: The relations between the inlet temperature of the 4th reactor and its coke content on the catalyst, and the effects of coke on countercurrent CCR reaction were investigated at a 600kt/a countercurrent CCR unit of SINOPEC Jinan Branch Company. The results showed that the inlet temperature of the 4th reactor had a great influence on its coke content and total coke amount of the whole reactor system. The lower inlet temperature of the 4th reactor could reduce the total coke amount of countercurrent CCR; With the increasing of coke content on catalysts, the temperature drop in each reactor reduced, the yield of aromatics and hydrogen apparently decreased, and the conversion of both naphthene and paraffin decreased; and the conversion rates of low carbon number naphthene and C5 ring naphthene decreased more than that of high carbon number and C6 ring naphthene, respectively; the conversion rate of iso-paraffin and low carbon number normal-paraffin decreased greater than that of normal-paraffin and high carbon number normal-paraffin, respectively. The optimization direction of countercurrent continuous reforming technology is to control the overall carbon accumulation level on catalyst, especially to reduce the carbon accumulation on the 4th reactor as far as possible.

Key words: countercurrent continuous catalytic reforming, coke deposition, naphthene conversion, paraffin conversion