关键词: 甲醇水溶液, 双效精馏, 模拟, 优化, (火用)

Abstract: Methanol-water mixtures with different compositions exist in many industrial processes, and the main consideration is energy consumption when separating methanol and water. In view of the separation process of methanol-water with methanol concentration of 10%-90% (mass fraction), different distillation models with light split forward, light split reverse and feed splitting were adopted. Using "Design Spec/Vary" function to find the values of distillate flowrate and reflux ratio that the distillate composition to 99.85% (mass fraction) methanol and the bottoms composition to 10^-5 methanol. The sensitivity analysis method was used to optimize the number of trays and the feed trays to obtain the minimum annual total cost (TAC). Furthermore, the energy loss of each process under the minimum TAC condition is compared and analyzed. When the methanol concentration of the raw methanol-water mixtures is 30% or less, the TAC of the feed splitting is the smallest; when the methanol concentration of the raw methanol-water mixtures is 50% or more, the TAC of light split reverse configuration is the smallest. In the case of minimum TAC for each process, the exergy loss of feed splitting process is the smallest when the methanol concentration of the raw methanol-water mixtures is 10% or less; the exergy loss of light split reverse process is the smallest when the methanol concentration of the raw methanol-water mixtures is 30% or more. The TAC and exergy loss analysis of methanol-water mixtures separation can provide a theoretical reference for the optimal double-effect distillation of methanol-water with different feed compositions in industry.

Key words: methanol-water, double-effect distillation, simulation, optimization, exergy