Abstract: This study employed the Box-Behnken design in response surface methodology (RSM) to optimize pre-distillation and pressurized distillation column parameters in methanol distillation. Statistical and fitting analyses demonstrated the effects of operational parameters and their interactions on product purity and operating costs. Results showed that for methanol mass fraction in the product, the top distillate of the predistillation column (D₁), the interaction between D₁ and the top distillate of the pressurized distillation column (D₂), and the interaction between the theoretical plates of the pressurized distillation column (N₂) and its reflux ratio (R₂) significantly affected the outcome, in addition to pressurized distillation column parameters. Acetone mass fraction was mainly influenced by pre-distillation column parameters and their interactions, with minimal relation to the pressurized distillation column. Operating costs were primarily affected by the reflux ratio (R), withdrawal (D) of both columns, and their interactions. Optimization strategies involved increasing theoretical plates and reducing reflux ratios compared to the initial plan, achieving energy-saving and consumption-reduction goals. The process required the pressurized distillation column ‘s methanol mass fraction to exceed 99.80%, acetone mass fraction below 2 × 10^-8, and formaldehyde mass fraction below 5 × 10^-9, with a feed rate of 6100 kg·h^-1. Plans A, B, and C achieved energy-savings of 29.80%, 21.78%, and 25.50% respectively, while ensuring separation efficiency and product quality. This research provides theoretical and practical guidance for optimizing the methanol distillation process, helping to reduce energy consumption and production costs, thereby enhancing corporate competitiveness.

Key words: Methanol distillation, Response surface methodology, Box-Behnken design, Parameter optimization, Energy-saving and consumption reduction, Operating cost

摘要： This study employed the Box-Behnken design in response surface methodology (RSM) to optimize pre-distillation and pressurized distillation column parameters in methanol distillation. Statistical and fitting analyses demonstrated the effects of operational parameters and their interactions on product purity and operating costs. Results showed that for methanol mass fraction in the product, the top distillate of the predistillation column (D₁), the interaction between D₁ and the top distillate of the pressurized distillation column (D₂), and the interaction between the theoretical plates of the pressurized distillation column (N₂) and its reflux ratio (R₂) significantly affected the outcome, in addition to pressurized distillation column parameters. Acetone mass fraction was mainly influenced by pre-distillation column parameters and their interactions, with minimal relation to the pressurized distillation column. Operating costs were primarily affected by the reflux ratio (R), withdrawal (D) of both columns, and their interactions. Optimization strategies involved increasing theoretical plates and reducing reflux ratios compared to the initial plan, achieving energy-saving and consumption-reduction goals. The process required the pressurized distillation column ‘s methanol mass fraction to exceed 99.80%, acetone mass fraction below 2 × 10^-8, and formaldehyde mass fraction below 5 × 10^-9, with a feed rate of 6100 kg·h^-1. Plans A, B, and C achieved energy-savings of 29.80%, 21.78%, and 25.50% respectively, while ensuring separation efficiency and product quality. This research provides theoretical and practical guidance for optimizing the methanol distillation process, helping to reduce energy consumption and production costs, thereby enhancing corporate competitiveness.

关键词: Methanol distillation, Response surface methodology, Box-Behnken design, Parameter optimization, Energy-saving and consumption reduction, Operating cost