Conceptual Design Of Reactive Distillation Process For Esterification Reaction System Based On Structured Catalytic Packing

As one of the important means of chemical process intensification,reactive distillation technology can greatly improve the efficiency,reduce the energy consumption and the investment of the equipment by coupling the two units of the reaction and distillation into one device and promoting each other.However,due to the complex coupling effect of the reaction and mass transfer in the reaction distillation column,the difficulty of the reaction distillation design process is increased.Therefore,it is necessary to study a design method which can carry out the feasibility analysis and conceptual design to avoid improper design leading to the failure of reactive distillation process.Process feasibility analysis and catalytic packing are two key issues in the process of reactive distillation development and have been the bottleneck of the academic and industrial research to explore the development of reactive distillation.The esterification reaction is a kind of system which is characterized by chemical equilibrium limitation and is suitable for the use of reactive distillation technology.Because of the wide variety of esterification reactions and the lack of systematic design method,the catalytic packing suitable for every reaction system is very different and their industrial applications are also subject to a certain degree of restrictions.This thesis mainly carries out the following research contents in view of the above problems:1)On the basis of the original graphic method,the residue curve equation was deduced in detail and the model was constructed and solved by Matlab software.At the same time,the singularity,separation space and separation boundry were introduced.The basic design equations and models of residue curve and reactive residue curve were deduced,and the feasibility analysis rules were discussed in detail.2)The reaction kinetics and reaction equilibrium constant of the esterification reaction of acetic acid with n-amyl alcohol were determined by using a SiC structured catalyst with HZSM-5 molecular sieve in a batch reactor.The effects of catalyst concentration,reaction temperature and molar ratio of acetic acid to alcohol on the reaction rate were investigated under the elimination of internal and external diffusion.The kinetic data were fitted by quasi-homogeneous reaction model.The equilibrium constant results show that the enthalpy of reaction is positive and the reaction is endothermic.Furthermore,the effect of feed flow and reaction temperature on the reaction rate were investigated in the tubular reactor for the structured catalytic packing.On the basis,the efficiency factor of the structured catalytic packing in the tubular reactor was proposed and the reaction kinetic equation of structured catalytic packing in the tubular reactor was obtained in the presence of external diffusion.3)Based on the reactive residue curve method proposed in this paper,and appropriate phase equilibrium thermodynamics and reaction kinetic model for the research system,two typical esterification systems of propyl propionate and n-amyl acetate were used for feasibility analysis and conceptual design.The feasibility of the process,separation space,separation boundaries,and the initial conceptual design were determined.