Study On Optimization Of Energy Utilization Of EO/EG Plant

Ethylene oxide which is one of derivatives of ethylene is a prime raw material for petrochemicals. Most of Ethylene oxide reacts by addition with water to yield Ethylene Glycol(EG). So in Petrchemicals plants Ethlene oxide/Ethylene Glycol Process is during the most important production equipments. There are eleven EO/EG production equipments in China.Compare to the foreign EO/EG production equipments, they are out of time,Because they are based on technologys of 20 years ago. Energy utilization and water utilization of these equipments is higher than that of foreign equipments. Research on optimization of EO/EG process to reduce production cost is presented.The research based onEO/EG process' energy conservation of Petrochina Liaoyang Ld. This article optimize EO/EG process by "Pinch analysis" and reactive distillation new process. Such work has been done:(1) Analysis and Evolution of energy Utilization for total process system ,a newly developed method and tool based on pinch technology are used in a case study to investigate the potential of energy Utilization in a EO/EG plant. By use of pinch tools such as the grand composite curve and the splitting grand curve ,the location of energy "bottle-neck" has been found ,and evolution strategies were provided effectively. At the same time,retrofit was putforward by use of chemical simulation software--aspen plus and a software developed byourselves,and the profit is remarkable.After all. of these retrofits are implemented, steam utilization can reduce 30%, cool water can reduce 14%.(2) A new hydration process of water and EO to produce EG by reactive distillation is put forward in a creative way.First a generalized programming formulation is presented for the design of reactive distillation columns using tray-tray, phase equilibrium and reaction kinetics equations. Solution of the model yields the optimal feed tray locations, mumber of trays, reaction zones, and operating and design parameters.Now essentially all ethylene glycol is produced by the hydration of ethylene oxide. Water and ethylene oxide are introduced to reator in proportion of 20-22:1. There will need a lot of steam to separate water from production. Reactive distillation producing EG is a new process,which can extremely reduce investment and manipulation fee. The results show thatthe mole proportion of water and ethylene oxide introduced to the reactive distillation column is gone down to from 20-22:1 to 1:1,and the conversion rate achieves to about 100%,and the selectivity to 92.3%.The process has been simplified extremely.