Analysis And Reformation About Problems Of Distillation Column Of Catalytic Cracking Unit

Catalytic Cracking Unit of JinXI Petrochemical Corporation was designed by BeiJing Design Institute 1986. Processing ability of the two stage riser in the unit was enlarged in September 2003,the throughput was increased from 800,000t/a to 1000,000t/a. The target of the reformation is improving processing ability, adding residuum and decreasing olefin content of gas oil.After reformation there were some problems about distillation column. First ,pressure drop of the whole column was higher than before. Second ,operating stability was lower and dry point of gas oil waved frequently. Higher pressure drop made it difficult to recycle gas oil, also made olefin content of gas oil higher , thus affected the effect of the reformation.In order to solve above problems, I checked and calculated related parameters of the distillation column with ProII software. After technology simulation and equipment design calculation , I found that opening ratio of plate of the first intermediate reflux was not designed properly , downcomer square was lager that than it should be, these problems resulted in actual operating difficulties. Not accurate flow simulation calculation and not familiar with proper of frozen tongue tray and design calculation result in above problems.Comparing nowadays popular super-v tray, frozen tongue tray and ADV tray, I put forward reforming distillation column with super-v tray.In April 2004, super-v tray was adopted in this unit .The result is satisfied. Distillation column runs stably, also can be operated in a large scale , pressure drop of the whole column is below 42000Pa .The quality of gas oil come up to the standard., same with olefin content. super-v trays were used in distillation column of Catalytic Cracking Unit successfully .