Kianinia Mahsa, Abdoli Seyed Majid
Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz 51335-1996, Iran.
ACS Omega. 2021 Aug 20;6(34):22447-22453. doi: 10.1021/acsomega.1c03513. eCollection 2021 Aug 31.
Acetone and -heptane are common solvents in the pharmaceutical industry and they have been found in wastewater. Under atmospheric conditions, the mixture of these compounds creates a minimum-boiling azeotrope. The extractive distillation process with a high boiling solvent is commonly utilized to separate the azeotropes in the industry to minimize waste, reuse resources, achieve clean production, and preserve the environment. In this work, extractive distillation was applied to separate the binary azeotropic system of acetone and -heptane in wastewater using butyl propionate as a solvent. The characteristics of the process are designed and simulated via Aspen Plus. The simulation results showed that to get a distillate containing at least 99.5 mass% acetone, a solvent-to-feed ratio of 1.4, a reflux ratio of 1.5, a number of stages of 30, a feed stage of 26, a solvent stage of 10, and a solvent temperature of 298.15 K were required. The optimum operating parameters of the process were also obtained using the NLP optimization method, with the minimum total annual cost as the objective function. While the process was operating in optimal mode, CO emissions were calculated to be 0.0780 kg CO/kg feed.
丙酮和庚烷是制药行业常用的溶剂，且已在废水中被发现。在大气条件下，这些化合物的混合物会形成最低沸点共沸物。工业上通常采用以高沸点溶剂进行萃取精馏的方法来分离共沸物，以减少浪费、资源再利用、实现清洁生产并保护环境。在这项工作中，采用丙酸丁酯作为溶剂，通过萃取精馏来分离废水中丙酮和庚烷的二元共沸体系。利用Aspen Plus对该过程的特性进行了设计和模拟。模拟结果表明，要得到丙酮质量分数至少为99.5%的馏出物，需要的溶剂与进料比为1.4、回流比为1.5、理论塔板数为30、进料位置为第26块塔板、溶剂进料位置为第10块塔板，且溶剂温度为298.15K。还采用非线性规划（NLP）优化方法，以年总成本最小为目标函数，获得了该过程的最佳操作参数。当该过程以最佳模式运行时，计算得出的CO排放量为0.0780 kg CO/kg进料。
