聚乙烯醇工艺副产醋酸甲酯羰基合成醋酸工艺探讨

Study on acetic acid synthesis by carbonylation with the byproduct of methyl acetate in polyvinyl alcohol process

针对聚乙烯醇工艺存在的能耗高、酸性废水量大的问题,以及典型羰基合成醋酸工艺的反应特征,提出了聚乙烯醇工艺副产醋酸甲酯用于羰基合成醋酸的路线。该路线既可解决聚乙烯醇工艺的高能耗问题,又可为羰基合成醋酸工艺提供更廉价的原料。利用同时拥有两种生产装置的条件,设计了一种3阶段试验方案,醋酸甲酯从2%(质量分数)开始添加试验逐步扩展到工业规模,验证了结合聚乙烯醇合成和羰基合成醋酸两种工艺的技术可行性和经济可行性。一套1.00×10^(5)t/a的聚乙烯醇装置副产的醋酸甲酯基本可以被一套3.00×10^(5) t/a的羰基合成醋酸装置消化。聚乙烯醇和羰基合成两工种工艺的结合,聚乙烯醇工艺中1.0 MPa(G)蒸汽、电和二级脱盐水单耗分别降低了8.8 t/t、9.1 kW·h/t和1.2 t/t。

Aiming at the existing problems of high energy consumption and high dosage of acid wastewater in the polyvinyl alcohol process,and the reaction characteristics of typical acetic acid synthesis by carbonylation,the route that using the byproduct of methyl acetate in the polyvinyl alcohol process to synthesize acetic acid by carbonylation was put forward.This route can not only solve the problem of high energy consumption of polyvinyl alcohol process,but also provide cheaper raw materials for the syhthesis of acetic acid by carbonylation.With the company has suitable devices for both process mentioned above,a three phases test program was designed with adding methyl acetate gradually from 2%(mass fraction)to industrial scale,which verifies the technical and economic feasibility in the combination of the acetic acid synthesis by carbonylation and polyvinyl alcohol processes.The byproduct of methyl acetate in the 1.00×10^(5) t/a polyvinyl alcohol plant can be consumed completely by the 3.00×10^(5) t/a acetic acid plant by carbonylation.After the combination,the unit consumption of 1.0 MPa(G)steam,electricity and secondary desalted water of polyvinyl alcohol product decrease by 8.8 t/t,9.1 kW·h/t and 1.2 t/t,respectively.