Abstract:  

This paper introduces the problems of high pressure drop, low total conversion of mixed aromatics and high hydrogen consumption in the reactor of disproportionation and transalkylation unit of a company. Although some operational suggestions were put forward to maintain the operation of the unit, the operating pressure of the reactor continued to rise, and the reactor was forced to shut down for maintenance after about 6 months. It was found that the diffuser at the reactor inlet was seriously damaged, the catalyst bed was seriously disturbed, and the catalysts were powdered and coked. The diffuser at the reactor inlet was repaired, the catalysts at the top of the reactor were discharged, screened and refilled, and some fresh catalysts were added. After the unit was restarted up, the operation parameters were still unsatisfactory, and the catalysts were replaced in August 2018. Then the total conversion of mixed aromatics, the total selectivity of benzene and C₈ aromatics and the hydrogen consumption reached or surpassed the design value.

Key words: disproportionation and transalkylation unit；reactor inlet diffuser；catalyst；total conversion of mixed aromatics；total selectivity of benzene and C8 aromatics； hydrogen consumption')">FONT-FAMILY: " Roman?,serif;? New Times>disproportionation and transalkylation unit；reactor inlet diffuser；catalyst；total conversion of mixed aromatics；total selectivity of benzene and C8 aromatics； hydrogen consumption