Feasibility Analysis And Process Simulation Of Reactive Distillation Of Cyclohexene Hydration

Cyclohexanol is an important high boiling organic chemical intermediate,it mainly used to produce the adipic acid,caprolactam and polyamide 6,6.Which are the intermediates for the production of Nylon 6,6 and Nylon 6.Meanwhile,it widely be used in the manufacture of pharmaceuticals,coating,fuel,etc.Currently,there are three methods which are mainly used to produce cyclohexanol,including phenol hydrogenation,cyclohexane oxidation process and cyclohexene direct hydration.Phenol hydrogenation encounters high prices of phenol and heavy consumption of hydrogen,and cyclohexane oxidation process suffers from safety risks,rather low selectivity,low conversion,high energy demand,etc.A more economical and safer process has been developed successfully by Asahi Chemical Industry Co.,Ltd.,the process includes two steps,first the selective hydrogenation of benzene react to cyclohexene,and then cyclohexene direct hydrate to cyclohexanol.After that the process of cyclohexene direct hydration is attracting more and more attention and research.In recent years,cyclohexene direct hydration process has become a research hotspot,it overcomes the disadvantages of traditional methods but still suffers from rather low equilibrium conversion and fairly slow reaction rate.In order to solve the above-mentioned issues,this paper proposes a method that combines reactive distillation process with a cosolvent into the system to produce cyclohexanol.To develop this novel technology,the research focused on the following aspects:(1)The isobaric vapor-liquid equilibrium data of cyclohexene + isophorone and cyclohexanol + isophorone were determined by a Rose-Williams still under atmospheric pressure of 101.32KPa,respectively.The absent binary interaction parameters of cyclohexene + isophorone and cyclohexanol + isophorone of the system were correlated and obtained by NRTL model,respectively.(2)Reactive distillation is a process combining reaction and separation in a single apparatus,which presents numerous advantages-improved efficiency.On the basis of thermodynamic model and kinetic model,the residue curve mapping(RCM)was used to conduct a conceptual design for the reactive distillation coupling process of cyclohexene hydration reaction.Then,we investigated the effect of Da number for the system and analyzed the feasibility of cyclohexene direct hydration reactive distillation process with a cosolvent.(3)Based on the equilibrium stage model,the process simulation software Aspen Plus was used to simulate the process of cyclohexene direct hydration reactive distillation process with a cosolvent.During the research process,this paper discussed the operating conditions including the molar ratio of isophorone and cyclohexene,the molar ratio of water and cyclohexene,the pressure of column,stage numbers of reactive zone,stage numbers of stripping section and stage numbers of rectifying section,which have effects on the cyclohexene conversion and heat duty of the system to optimize the process and obtained the suitable operating conditions,the simulation results were satisfactory.