丙酮-丁醇精馏工艺中丁醇塔的优化模拟

针对发酵法的丙酮-丁醇精馏工艺中能耗较高的问题,提出一个优化方案:在醪塔增加一个侧线出料,醪塔的侧线与塔顶出料分别从不同位置进入丁醇塔,并增加丁醇塔的塔高,同时将丁醇塔内的分相罐移至塔外。采用PRO/Ⅱ化工流程模拟软件对优化后的丁醇塔进行模拟计算,考察了理论塔板数、进料位置、回流比对分离性能的影响。优化的丁醇塔为40块理论塔板,两股进料位置分别为第8块和第14块理论塔板,回流比为4。在此条件下,丁醇塔塔顶馏出物中水的质量分数由8.56%降为2.18%,丁醇的质量分数由2.71%降为微量,蒸汽消耗量与原丁醇塔相比降低了52.6%。工业试运行结果与优化结果吻合良好。

Simulation and Optimization of Butanol Column Operation in Distillation System of Acetone-Butanol

An optimized distillation system for separation of butanol and acetone from fermentation process was proposed to solve the problem of high heat duty of butanol column.In optimized distillation system a side stream was drawn from the prefractionator.The overhead stream and side stream of prefractionator were fed to appropriate plates of butanol column separately.The plate number of butanol column was increased,and the phase separation tank was moved out of the butanol column.The effect of suitable theoretical plate number,feeding positions of the two streams and reflux ratio on separation performance and heat duty of butanol column were simulated by means of PRO/Ⅱ software.The obtained operating parameters were as follows:the theoretical plate number of butanol column 40,the two inlet plates 8th and 14th,and the reflux ratio 4.Under the above conditions,the mass fraction of butanol in overhead stream drops from 2.71% to trace,the mass fraction of water in overhead stream drops from 8.56% to 2.18% and the steam consumption is thus saved by 52.6%.The test running data met the simulation satisfactorily.