Simulation Of Reactive Distillation Synthesis Of Butyl Acetate

N-butyl acetate(BuAc) is an important organic chemical material which plays a significant role in chemical, pharmaceutical and spice industry. At the present time,domestic butyl acetate synthesis are experiencing a series of problems, such as too much secondary reaction, complicated final treatment, high corrosion and serious pollution,which is due to the fact that mainly industrial butyl acetate production is catalysed by concentrated sulfuric acid. This study put forward solid acid catalyzed reactive distillation process, a new technology of BuAc production, and using Aspen Plus Dynamics to simulate and improve the continuous production process.This paper describes the composition and temperature of azeotropes in butyl acetate system through NRTL model. The thermodynamic properties in system show that there are multiple binary and ternary azeotropes at the top of reactive distillation column.Through integrating separator into the top of distillation column, the total-reflux organic phase makes the system cross distillation equilibrium line, so that by-product water is separated efficiently. In order to minimize the total annual cost(TAC), an optimal column structure is designed in this paper. The results showed that the influence from the number of theoretical plates in rectifying and stripping sections is not significant.However, a reasonable number of reaction plates and feed position can reduce TAC effectively. Moreover, feed ratio is the most important and sensitive manipulate variables.In addition, three control methods were proposed for the reactive distillation process of butyl acetate, respectively were two point temperature control method, temperature and concentration control method and cascade control of temperature and concentration.And a series of operations in reactive distillation column were simulated dynamically through Aspen Dynamics including feed flow rate ±10%, feed concentration of ethanol and acetic acid-5% and disturbance test-10%. The results showed that feed flow rate and feed composition of acetic acid have major impact on quality. Besides, two point temperature control method and cascade control of temperature and concentrationmethod both have excellent exclusion effect on different disturbances. Among them, two point temperature control method has the advantage of low cost in equipment investment and maintenance. On the other hand, cascade control of temperature and concentration responses quickly when raw material disturbances become frequent, which brings substantial cost reduction in production.