Process Design And Operation Of 180000 Tons/Year Benzene Extraction Unit

In order to meet the requirements of gasoline blending in gasoline,benzene must be carried out in order to meet the requirement of the benzene in gasoline blending with other groups of 5%~8%.In this paper,the necessity of using extractive distillation process is demonstrated by comparing the two kinds of methods,such as the separation of benzene in catalytic reforming gasoline,liquid extraction and extractive distillation(ED).Compared with the liquid extraction process,the extraction distillation process is relatively simple,the energy consumption is low,the yield and quality of benzene can meet the requirements of the index.Sulfolane was selected as solvent in the extractive distillation process for its higher selectivity,solubility and good thermal stability.The 600000 tons / year continuous reforming unit of China Petroleum Karamay Petrochemical Co was put into operation in the end of 2011,the original 50000 tons / year of benzene extraction device cannot meet the requirements of separation of benzene,so the company built 180000 tons / year of benzene extraction device.The device uses the extractive distillation and separation of benzene(SED)provided by the Petroleum Chemical Research Institute(RIPP).This process has the advantages of simple process,low investment,low energy consumption and high benzene yield.The device was successfully driven in May 2013,after calibration,the technical and economic indicators meet the design requirements: the oil content of the reforming of the benzene content from 6% to less than 1%,the purity of benzene products more than 99.9%,benzene recovery rate is greater than 99%.But in the subsequent operation of the device there are some practical problems,such as the reboiler of the recovery tower occurres leakage,the content of benzene in raw materials is too low and so does the device processing load.Through careful analysis,the corresponding measures are formulated,and the problems are solved successfully.At the same time,the experience of the operation of the device is also analyzed and summarized in order to ensure the stable operation of benzene extractive distillation unit.