| Ethylene Glycol Monobutyl Ether (EGMBE) is an eco-friendly EO-based solvent andwidely used in industries. The conventional production technologies can not onlymatch the increasingly demand of EGMBE but also have lots of disadvantages, suchas lower selectivity of desired product, higher energy consumption, as well as thesevere corrosion problem due to the utilization of homogeneous catalysts, etc. In orderto overcome these shortcomings and fulfill the demand of EGMBE, it is essential butsignificant to develop new technologies to produce EGMBE. Catalytic distillation is atypical process intensification technology which has been successfully employed inproducing over150chemicals, the production of EGMBE using catalytic distillationhas many advantages such as higher selectivity of desired product, lower energyconsumptions, lower capital investment and so on, so it is very important to acceleratethe industrialization of production of EGMBE using catalytic distillation. The studyfocuses on developing mathematical model to analyze the influence of operatingparameters to the process and the interaction between reaction and distillation, as wellas to present the heat utilization and energy-saving results under various operatingconditions using thermodynamic analysis so as to optimize the process. Also, themodel and heuristics obtained in this research will be further used to improveindustrial design, operation and control and so on.(1) A steady equilibrium mathematical model solved by Newton-Raphson Methodsand performed on Visual C++6.0is set up. The effects of the key operating parameters(such as pressure, temperature, reboil up ratio, and molar feed ratio of methanol to EO)on selectivity of EGMBE and conversion of EO are investigated to gain the optimaloperating conditions of column. The optimal operation parameters are determined tobe: Pressure2atm, reboil up ratio9.Under this condition, the simulation results arewell agreed with the experimental results, the temperature, liquid and vapor molar composition as well as flow profiles in the column are presented too.In addition, the effect of kinetics on EO conversion and selectivity of EGMBE isdiscussed. The simulation results suggest that increasing Damk hler number is helpfulto improve the conversion of EO and selectivity of EGMBE. While Da is small, EOcan not be consumed totally, the larger the Da is, the bigger the conversion will beuntil arrive at100%; higher selectivity of EGMBE benefits from larger Da, when Dais bigger then9, the maximum selectivity,94%, can be obtained.(2)An exergy analysis model is established with the simulation results from steadyequilibrium mathematical model. The exergy loss profiles in the column is obtained,the main exery loss position and possible causes are investigated. It is suggested thatmost of the exergy is lost in the EO Feed stage, and the total loss in the column isinfluenced by EO feed location and Butanol feed rate, the lower the EO feed locationis and the bigger the Butanol feed rate is, the smaller the total exergy loss will be.Inorder to get the minimum exergy loss, the suggested EO feed location is stage7,Butanol feed rate is0.8kmol·hr-1.(3) A heat effect analysis model using the simulation results from steady equilibriummathematical model is set up in order to get the reaction heat profiles and investigatethe influence of heat effect to liquid and vapor flow in the column. The heatutilization factor is calculated, the effect of temperature on heat utilization factor isstudied too.The study shows that the system researched has strong heat effect, which shouldconsider heat effect in reactive distillation column design. The heat utilization factoris bigger when the temperature is higher, the reaction heat mainly is released on EOfeed location. The liquid and vapor flow profiles changes with various Butanol feedrate, and the main difference occurs in stage7, when Butanol feed rate is small(0.3kmol·hr-1), the vapor flow surpass the liquid one, with the increase of Butanol feed rate, the vapor flow decreases and meantime the liquid flow grows up, and theyalmost equal at0.7kmol·hr-1.In order to make the reaction zones play an role asstripping section, there exists an minimum Butanol feed rate.(4) The study using CGCC(Column Grand Composite Curve) investigate the effectof distribution of catalysts and EO feed condition on energy consumption. It showsthat the distribution of catalysts and EO feed condition have strong impact on energyconsumption. After optimizing catalytic distribution, the energy consumption can bedecreased by42%; EO is feed on five staged equally, the energy consumption can bereduced by45%compared by only one stream in stage. |
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