Study On The Process Simulation And Energy Saving For BDO Purification Process

1,4-butanediol or BDO is an important organic chemical which can be used to produce THF,GBL,PBT and so on.The production methods for BDO include the Repee process,the technique with maleic anhydride,the process with butane and maleic anhydride,etc.The Davy process with maleic anhydride for the manufacture of BDO is the newest technique,which is superior to others.BDO is widely used,so the demand for it is increasingly high. Because of the international techniques monopoly,the factories for the production of BDO in China have to adopt two suites of apparatuses from foreign countries.So it is very significant and necessary for the creation of new techniques which are owned by the Chinese for the manufacture of BDO.Distillation techniques for the purification of BDO are researched in this paper by the use of the process simulation software Aspen Plus.By the simulation and optimization of the several processes related, the optimal process is found.The strategy for the energy saving of the distillation process is also studied.Some components are not included in the database of Aspen Plus.The thermodynamic data needed for the definition of the components which are not contained in the database can be obtained from the literature plus the PCES system of Aspen Plus.The methanol and water are contained in the feed which is very unideal liquid mixture and the columns in use is operated in low pressure.So the NRTL and Wilson activity coefficients models are selected as the thermodynamic model for the simulation of the distillation process.It is proofed reliable by the comparison of the experimental results and the simulating results.According to the purpose of separation,there are five sequences or schemes available theoretically if the simple columns are applied.The energy consumption of scheme 4 and 5 is very high which can be deduced by analyzing the five sequences theoretically.The scheme 1 to 3 with simple columns were studied by the use of the simulating software Aspen Plus.The sensibility analysis for the processes were done and the optimal parameters of each process were obtained.By analyzing and comparing the simulation results,the energy consumption of scheme 1 is the lowest in the three schemes simulated.Three complex column schemes which are suggested on the basis of scheme 1. And they were simulated by the use of Aspen Plus,the sensibility analysis of the three processes were done and the optimal data were also acquired.Though the recovery ratio of BDO in scheme 1 with complex columns is very high,its energy consumption is the lowest.The energy saving methods of scheme 1 with complex columns were researched.The temperature difference between the towers with heat integration can be reached by the change of the pressure of the columns associated.The reboiler heat duty and the condenser heat duty can be saved about 20% by the adoption of heat integration or not.