Research Of Reactive Distillation In 2,3-Butanediol Separation

As an important chemical and potential energy source,2,3-butanediol has been applied in many fields. Recently, production of 2,3-butanediol from microbial fermentation is attracting people’s attention. However, due to the high boiling point and high hydrophilic property, 2,3-butanediol is hard to be separated from fermentation broth by common methods. Through aldolization,2,3-butanediol and n-butanal can form 1,2-dimethyl-4-propyl-3,5-dioxolane (DPD) which is hydrophobic and can be easily extracted by n-butanal.2,3-Butanediol with high concentration can be obtained by hydrolyzing DPD. In order to promote the low conversion of DPD hydrolysis, a special process is needed. Thus, DPD hydrolysis in reactive distillation column was studied in this research. The main contents are as follows in details:(1) According to the characteristics of DPD hydrolysis system, appropriate gas chromatography method was established to determine the component concentration.(2) Type and amount of catalyst were studied. On this basis, kinetic parameters of aldolization and hydrolysis were determined. Hydrolysis distillation experiment was studied. On the suitable operating condition, the recovery rate of 2,3-butanediol at bottom reached up to 88.5%.(3) Simulation of DPD hydrolysis distillation was studied on the basis of experiment. DPD physical properties were estimated and RadFrac module was applied. Simulation using UNIFAC as property method was proved to fit with the experiment.(4) Conditions of hydrolysis distillation column was optimized. Appropriate feeding method, stage number, feeding stage and suitable operating condition were determined.(5) DPD hydrolysis was conducted under the guidance of optimization. Recovery rate of the product reached up to 90.4% with 73.4wt% concentration. After that,2,3-butanediol concentration was over 98wt% through vacuum distillation.