Research On Engineering Analog Caculation And Modification Of The Demethanizer In Ethylene Plant

The 220000tons/year renovation and expansion project was completed in 2002 for the ethylene plant Dushanzi Petrochemical Company.From the operation of the plant for nearly a year,ethylene loss was as high as 2.0～5.0%,and far higher than the requirement of 0.05%. The major reason for the loss increase of ethylene was that the feed of cracking furnace was very different from before the improvement,and the improvements of some systems including the demethanizer were not enough,which affected the production capacity of the whole plant.The paper discuss mainly the demethanizer that is one of the key equipments causing the loss of ethylene to increase.The problems founded in the operation of the demethanizer was simulated and hydraulicly calculated using the process simulation software PROⅡ,and the reason for the increase of the loss of ethylene caused by the deficiencies of the improvement of the demethanizer was found.After the measures to improve the demethanizer was implemented using the result of the simulstion, the loss of ethylene was reduced below 0.5%,and reached the requirement.At the same time,the research of the subject have a certain significance for the settlement of other issues encountered in the course of the ethylene plant expansion.