Research On Industrial Application And Optimization Of SGEB Technology Of Ethylbenzene With Dry Gas

Catalytic dry gas,the byproduct from CCU of a refinery usually containing 10³0%of ethylene,is often used as fuel,which leads to the problem of ineffective utilization of precious resource.In recent years,ethylene has become a scarce material and the demand for styrene has also increased rapidly at the meantime.Thus,more and more refineries have decided to make full use of the dilute ethylene contained in dry gas to produce ethylbenzene-one of the main production materials of styrene.Therefore,it has important practical significance to carry out research on the efficient utilization of catalytic dry gas and to develop more advanced technology of ethylbenzene with dry gas.In this dissertation,the first industrial application of packaged SGEB technology of ethylbenzene with dry gas independently developed by SINOPEC is analyzed.Firstly,the industrial application process is followed and studied.The key elements to industrial application have been found and the effectiveness of industrial application has been confirmed.And the problems existing in the process of industrial operation have been pointed out.Secondly,the self-developed catalyst,core of SGEB technology,is also carefully studied.Various factors affecting the performance of the catalyst and the catalyst's deactivation mechanism have been analyzed and studied,with the optimal operation conditions testified.Finally,the optimization of SGEB technology is studied.And a series of optimizations have been carried out,including pretreatment methods of raw material,reaction conditions,product efficiency improvement and energy-saving equipment.The results of industrial application show that the average load of the production unit is107.1%,and the product purity of ethylbenzene reaches 99.87%.The xylene content is621?g/g,with a benzene unit-consumption of 0.749t/tEB and a ethylene unit-consumption of0.274t/tEB.The main economic and technical indicators have reached the international advanced level of similar equipment.The results of the study on catalyst operation show that the reasonable arrangements of the temperature raising period and the temperature raising range are beneficial to better performance of the catalyst and can prolong its service life.The impurities in the catalytic dry gas or the raw material benzene can aggravate the coking of the catalyst,or cause its poisoning deactivation,which may lead to malfunctions of the equipment.The appropriate technical control conditions are as follows,reaction temperature range:350-360^oC,propylene content in catalytic dry gas:<1.5%,H₂S content:<=20?L/L,raw material benzene:no water content,alkaline result in neutral test.Through optimization of the technical process,the adverse effect of impurities on the catalyst has been reduced.Consequently,the activity and stability of the catalyst has been improved,which in turn has ensured long-period operation of the production equipment.The propylene recovery project implemented can increase the propylene recovery volume by750t/a,and the energy saving optimization measures of the fractionating tower can reduce the steam consumption by23500t/a.Thus,the energy consumption has been further reduced to improve the equipment efficiency.The development and industrial application of SGEB technology of ethylbenzene with dry gas are of great significance to further improvement of the production technology,expansion of the production capacity and getting rid of the dependence on foreign technology.