The traditional approach to solvent selection in the extractive distillation process strictly focuses on the change in the relative volatility of light-heavy components induced by the solvent. However, the total annual cost of the process may not be minimal when the solvent induces the largest change in relative volatility. This work presents a heuristic method for selecting the optimal solvent to minimize the total annual cost. The functional relationship between the relative volatility and the total annual cost is established, where the main factors, such as the relative volatility of the light-heavy components and the relative volatility of the heavy-component solvent, are taken into account. Binary azeotropic mixtures of methanol-toluene and methanol-acetone are separated to verify the feasibility of the model. The results show that using the solvent with the minimal two-column extractive distillation index, the process achieves a minimal total annual cost. The method is conducive for sustainable advancements in chemistry and engineering because a suitable solvent can be selected without simulation verification.

在萃取蒸馏过程中，传统的溶剂选择方法严格地集中在由溶剂引起的轻质组分相对挥发度的变化上。但是，当溶剂引起相对挥发度变化最大时，该方法的年度总费用可能不会很小。这项工作提出了一种启发式方法，用于选择最佳溶剂以最大程度地降低年度总成本。建立了相对挥发度与年总成本之间的函数关系，其中考虑了诸如轻重组分的相对挥发度和重组分溶剂的相对挥发度等主要因素。分离甲醇-甲苯和甲醇-丙酮的二元共沸混合物以验证该模型的可行性。结果表明，使用具有最低的两塔萃取蒸馏指数的溶剂，该工艺可实现最低的年度总成本。该方法有利于化学和工程领域的可持续发展，因为无需模拟验证即可选择合适的溶剂。