| Reactive distillation (RD) is an integration of distillation and reaction, which takes the advantage of distillation to improve the effect of chemical reaction. It has been an important intensification technology and successfully applied in the chemical industry. However, RD processes may be inhibited by their particular properties of the reaction systems. In this dissertation, the concept of RD intensified by an auxiliary reaction is studied. By introducing an auxiliary reaction, the characteristics of original system such as composition of azeotrope, reaction rates, alternative lightest and heaviest components are modified, which will intensify the system in the respect of distillation and chemical reaction. The methyl acetate (MeOAc) hydrolysis intensified by methanol (MeOH) dehydration is studied as an example where the latter serves as the auxiliary reaction. The main research works are listed as follows:The platform of analysis and simulation for the process of RD was developed based on the process simulator gPROMS. In the platform, the equilibrium and non-equilibrium models of RD were established while the arc-length continuation was extended to search the bifurcation points and multiply steady states for the chemical process including RD. The stability analysis of solutions was realized by evaluating the eigenvalues of the Jacobian matrix that was accessible to users in gPROMS. The examples of a classic adiabatic CSTR, a homogenous azeotropic distillation and methyl acetate synthesis by RD were used to specify the configuration and application of platform.A residue curve maps (RCMs) was developed to analyze the mechanism of intensification for the case with two chemical reactions and multiple components. The mechanism of intensification of MeOAc hydrolysis intensified by MeOH dehydration was studied in the respect of distillation and chemical reaction. The results show that, extra water can be supplied for the system by introducing MeOH dehydration, which avoids excessive water in the feed and high energy consumption in the downstream separation. Meanwhile, converting MeOH into H2O in the dehydration reaction facilitate the chemical equilibrium to forward direction, which enhance the conversion of MeOAc. Furthermore, MeOH as the product in the MeOAc hydrolysis reaction can be transferred into dimethyl ether as the byproduct.The conceptual design of MeOAc hydrolysis intensified by MeOH dehydration in the RD was implemented based on the developed platform. The effect of operating parameters such as pressure, reaction zone, feed stage, reflux ration and catalyst loading on the process were analyzed. The results reveal that, in the case of equal mole of MeOH and MeOAc as feed, MeOH and MeOAc can achieve100%conversion in the RD column while pure dimethyl ether and acetic acid are the top and bottom product, respectively. Thus, the effect of intensification is proved. Furthermore, as the rate MeOH dehydration is low, a pre-reactor was set before the RD column to convert MeOH into water in advance so that the energy consumption of RD column could be saved.As the advantange of effect of intenficaiton, two novel processes of recovery of MeOAc in the production of poly vinyl alcohol were developed. The optimal conditons were obtained by analysis of various operating parameters. Compared with traditional processes, high MeOAc conversion and high purity products could be reached and the equipment costs and energy consumption are significantly reduced with the help of these new processes. Furthermore, high purity DME could be produced as a more valuable product. |
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