Simulation And Optimization Of Ethylene Oxide For Preparing Ethylene Glycol

At present,the method of producing ethylene glycol is mainly petroleum process route,but there is widespread energy consumption and high production cost.It is very important to optimize the energy consumption of the device.This paper studies the process of ethylene glycol production from ethylene oxide based on the engineering example of a petrochemical company.The energy consumption was mainly concentrated in the process of ethylene oxide stripping and refining and the process of ethylene glycol distillation.It accounts for about 70%of the total energy consumption of the device.What's more,there is a large number of low-temperature heat source hasn't been rationally use.It's of great significance for recycling this part of the energy and optimizing the energy-intensive devices.After analyzing the process in detail,appropriate thermodynamic method is selected according to the characteristics of different systems.The model is established and solved by applying suitable solution to complete the steady state simulation of the process.The error between the simulation results and the design value is very small,which verifies the correctness of the model and the credibility of the data.It also lays the foundation for the optimization of the process design.Based on the simulation results,the data of the hot and cold streams is extracted.The energy consumption of the existing devices is analyzed based on the pinch theory and the potential energy saving of the system is found out.According to the principle of pinch design,the heat transfer network is tuned and modified to reduce the heat transfer that contrary to the pinch rules and improve the energy efficiency.Through changing the match between the streams and preheating the feed of ethylene glycol dehydration tower,a large number of low-temperature energy is recovered and the energy passing across the pinch is reduced.So that the heat of ethylene oxide refining tower by the steam heating reduced by 4.87 MW,saving 36.2%and the heat load of ethylene glycol dehydration tower reboiler reduced by 1.58 MW,saving 18.0%,which significantly reduces the consumption of utility engineering.For ethylene glycol distillation column,the indirect heat pump distillation technology is applied,which aimed at recovering the energy of overhead vapor to heat the reboiler.The simulation is carried out to determine the key operating parameters of the heat pump,also its energy consumption and performance parameters are analyzed.Compared with the conventional process,the heat load of the ethylene glycol refining tower is provided by the heat pump system completely.The steam energy consumption is reduced by 10.42 MW,the medium pressure steam is saved by 18.5 t·h-1 and the annual operating cost can save 45.26%.The performance of the heat pump is good and the energy saving effect is remarkable.