Simulation and improvement of the separation process of synthesizing vinyl acetate by acetylene gas-phase method

Vinyl acetate, as an essential organic chemical raw material, can be used to produce polyvinyl acetate, polyester vinyl alcohol, and other products. The existing classical vinyl acetate production process has the problems of low product purity and excessive heat load. In this study, in the classical design of the process, acetylene is separated first, and then acetaldehyde is removed with the formation of an azeotrope between ethylene acetate and water. Meanwhile, considering the solubility of acetaldehyde in water and insolubility of vinyl acetate in water, the process was optimized to separate acetic acid after removing acetylene, so as to avoid the azeotrope formation of vinyl acetate and water. The nonrandom two-liquid-Hayden–O’Connell thermodynamic hybrid model was used to simulate the classical process and improved process (IP). Finally, the reflux ratio and theoretical tray number of the main separation equipment of IP were optimized to get the better parameters. The simulated results show that the purity of vinyl acetate increased from 99.1% to 99.8%, the cooling energy consumption was reduced by 16.83%, and the thermal energy consumption was reduced by 6.18%. At the same time, the equipment investment was also decreased.