| The 500# unit of ethylene glycol (EG) equipments of Yanshan is the unit of producing EG through hydration reaction of ethylene oxide (EO) and dehydration of EG, which is composed of a tubular reactor and multiple-effect evaporation system (5-effect, MEES). The MEES adopts downcurrent operation.The specialized thermodynamics method(GLYCOL) is established for EG dehydration system in PROII and the binary interaction parameters of each component are obtained by the regression of experimental data.Above all, the model to 5-effect evaporation system has been developed based on PROⅡsoftware. The model is rational in contrast to the calculation of original designed parameters. Afterward, the method to optimize operation has been found and the dosage of once steam is reduced. Next, the new technics of producing EG has been presented by hydration rectification instead of routine hydration comparing routine hydration of EO and hydration rectification of EO. So the selectivity of the objective product can be increased and it is tested using EG device in Yanshan.At first, the simulation result and design data are shown to agree with each other very well through the analog calculation based on the original design data of MEE of EG. It is indicated that it is credible using GLYCOL thermodynamics method to simulate the dehydration process of EG. Secondly, the work situation is completed against 80% and 100% operation load. It is obtained that the feed(S-29)of MEES for EG is 74 t·h-1 and 93 t·h-1 respectively. The improved project has been presented in order to reduce the consumption of medium pressure steam and guarantee the product index. The operation of each tower on the level of 80% and 100% operation load respectively is optimized and the consumption of medium pressure steam is obtained. It can be seen that the consumption may drop to 13.5 t·h-1 and 17.3 t·h-1 when reducing reflux ratio. And the consumption is 13.05 t·h-1 against 80% operation load while increasing the reflux temperature. The consumption drops to 11.3 t·h-1和15 t·h-1 respectively owing to the increase of theoretical stage numbers.The analog calculation for the rectifying tower of EO hydration reaction has been carried out based on the model. The effect of factors such as reflux ratio, water proportion in the feed, EO entrance point, stage number in the stripping section and work pressure on the selectivity of MEG was mainly investigated. It is shown that water proportion in the feed and reflux ratio is the effective factor on the selectivity of MEG. With the same water proportion in the feed, the selectivity of the reaction rectification technics is higher than that of the routine reactor.One mid-test device of rectifying tower of EO hydration reaction has been established to check the validity of the simulation result in Yanshan petrochemical Co., Ltd. There are many feed openings and reflux jaws in order to make overall experiments on the effect degree to the MEG selectivity with the factors such as water proportion in the feed, reflux ratio, feed distribution, feed entrance point and work pressure and so on. At present, the experiment is still being done. But it is indicated from the exiting experimental data that the selectivity of MEG in reaction rectifying tower is higher than that in the routine hydration reactor.
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