醋酸乙烯单体回收单元的流程模拟与优化

Process simulation and optimization of vinyl acetate monomer recovery

采用Aspen Plus流程模拟软件,选取NRTL-HOC模型,对某公司10万t/a聚乙烯醇装置醋酸乙烯单体回收单元进行了全流程模拟,模拟结果与实际值吻合良好。在此基础上,对聚合一塔、聚合二塔和聚合三塔进行模拟优化,分析得到了优化后的工艺参数:聚合一塔汽提甲醇量为46 000 kg/h,聚合二塔混合物进料理论板数为32,聚合二塔萃取水量为19 000 kg/h,聚合三塔侧线采出为塔釜气相采出,聚合三塔回流比为4。在优化条件下,醋酸乙烯产品质量分数达99.95%,聚合二塔萃取水量减少了9.87%,聚合二塔和聚合三塔的总热负荷降低4.84%,节约了萃取水量,降低了能耗。

Process simulation of vinyl acetate monomer recovery unit in 100 kt/a poly vinyl alcohol device was carried out by using Aspen Plus simulation software with NRTL-HOC model. The simulation results conformed to the actual value. On the basis of this, the No. 1, No. 2 and No. 3 polymerization column were optimized. The results showed that the rate of methanol steam on No. 1 polymerization column was 46 000 kg/h. The feed stage of mixture stream on No. 2 polymerization column was 32. The rate of extraction water on No. 2 polymerization column was 19 000 kg/h. The side-stream position of product was on kettle and the type was vapor phase. The reflux ratio of No. 3 polymerization column was 4. Under optimized conditions, the mass fraction ratio of vinyl acetate reached 99.95%, the rate of extraction water of No. 2 polymerization column was decreased by 9.87% , the total heat duty of No. 2 polymerization column and No. 3 polymerization column was decreased by 4.84%. The results showed that it saved the extraction water and energy.