The Research On Gas Reactive Distillation Process Of Methyl Acetate Hydrogenation

The hydrogenation technology of methyl acetate to produce ethanol not only can be used to convert the large amount of methyl acetate which is produced in polyvinyl alcohol and purified terephthalic acid industries,but also be the critical step of the process of coal to ethanol.The traditional equipment of hydrogenation process contains a hydrogenation reactor and a series of complicated separation and recycle installations.A high mole ratio of hydrogen to methyl acetate and huge energy consumption is needed in traditional process.A gas phase reactive distillation process for methyl acetate hydrogenation was proposed to lower the needed mole ratio of hydrogen to methyl acetate and energy consumption.A mathematical model was developed to describe the behavior and performance of gas phase reactive distillation.The mathematical model was used to simulate and analysis the parameters of reactive distillation column.The results showed that the mole ratio of hydrogen to methyl acetate was 2.7:1 which was much lower than 10:1 for traditional process.Since the operating pressure of reactive distillation column is quite high,the pressure swing heat integration technology was applied to reduce the energy consumption.An optimization for reactive distillation process was conducted to minimize the total annual cost(TAC).The optimized reactive distillation process can save 18.10 % TAC including 41.10 % operating cost and 2.90 % capital cost,which means the reactive distillation process is promising.An exploration about the influences of catalyst non-uniform distribution was conducted to intensify the reactive distillation process.However,due to the kinetically controlled reactions,catalyst non-uniform distribution made very little difference.To further explore the influences of catalyst distribution of equilibrium limited reactive process,methyl acetate synthesis reactive distillation process was investigated.The methods including catalyst ununiform distribution and the relocation of catalyst section and the increase of the amount of catalyst were used to investigate the impacts on methyl acetate synthesis reactive distillation process.The results showed that 10.12 % of reboiler duty and 8.65 % of condenser duty can be saved by relocation of catalyst section and the increase of the amount of catalyst,which proved that catalyst distribution has great impact on equilibrium limited reactive process.Besides,an optimization of catalyst ununiform distribution was proposed to supply a feasible scheme to reduce the energy consumption of reactive distillation column.Through this optimization,the utilization efficiency of catalyst was improved and 13.90 % of reboiler duty and 11.93 % of condenser duty can be saved.