Heat-pump distillation and dividing wall column processes for 1,4-butanediol purification

1,4-Butanediol (BDO) is crucial for biodegradable plastics production and other specialty chemicals, making it essential for numerous industrial applications. However, the synthesis of BDO via the Reppe process introduces impurities such as ethylene glycol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol, and developing efficient BDO purification processes is necessary. Vapor-liquid equilibrium experiments were performed to obtain thermodynamic data, which were then correlated to determine the binary interaction parameters of the thermodynamic models. Batch distillation experiments were further conducted to validate the vacuum distillation for BDO purification. The benchmark separation process involved direct and indirect distillation columns, followed by dividing wall column (DWC) and heat pump (HP) implementations. Evaluation results revealed that the heat pump-assisted indirect distillation sequence (IDS-HP) achieved a remarkable 52% reduction in total annual cost, and the thermodynamic efficiency improved from 9.9% to 45.2%. The heat pump-assisted DWC (DWC-HP) demonstrated the potential to achieve net-zero CO 2 emissions. This research provides both theoretical and experimental foundations for the purification of BDO.