Study On Reactive Distillation Of N-Butyl Acetae Synthesis

An industrial equipment device was built in n-butyl acetate plant of Taisen Chemical Group. This equipment used strong acid action exchange resin as catalyst, acetic acid and n-butanol as raw materials. Its annual production capacity of n-butyl acetate was 5kt. The experimental study on it was taken, as a result, the optimal operation conditions were obtained. The concentration of n-butyl acetate on top can reach 84%～90%, and the concentration of acetate acid on top can below 0.003%, while the reflux ratio of organic phase was 1.7～2, the reflux ratio of water was 3.3～4.3, and the concentration of acetate acid in column bottom was 30%～50%. Compared with original process using H₂SO₄ as catalyst, the concentration of n-butyl acetate on top was improved by 3 percentage point, the vapor consumption was about 15% lower. It was shown that the catalytic distillation process can run continuously and steadily for long time.The Aspen plus was used to simulate the synthesis process of n-butyl acetate. The kinetics of n-butyl acetate synthesis reaction and liquid holdup was used in the simulation. The calculated results were in good agreement with the experiment data. Between the calculated result and the experiment data, the relative error of concentration of n-butyl acetate on top, concentration profile and temperature profile was lower than 6.49%. This calculation method was used to optimize the synthesis column and operating conditions. Optimized catalytic distillation column has two sections: 19 stages in rectifying section and 15 stages in reaction section. The optional reflux ratio of water is 3, and the reflux ratio of organic phase is 1.5, the concentration of acetate acid in column bottom is 27.91%. Under the precondition of keeping the concentration of acetate acid on top below 0.003%, the concentration of n-butyl acetate on top can reach 90%, and the energy cost of the esterification column and distillation dolumn is 10% lower than the industrial column.