Abstract: A novel process of three-column distillation was proposed for the purification of synthetic methanol. In the new process with double-effect distillation to realize heat-integration, the feed to the lower-pressure column was a side-stream with moderate methanol concentration drawn from a stage of the higher-pressure column above its feed stage.A better balance of separation duty between the higher-and lower-pressure columns was achieved, which reduced further the total heat consumption of double-effect distillation process.The salt and base components from the pretreatment column were separated and concentrated to the bottom stream of the higher-pressure column so that the bottom stream of the lower-pressure column contained>99.9% water. Then the water was recycled to the pretreatment column as the extracting water, which realized water-integration within the process and reduced the consumption of fresh soft water of the process. A comparative case study by steady-state simulation was carried out between the traditional two-column process (A), the present three-column process (B) and the new process (C). The result showed that process (C) reduced the heat consumption by 49.2% of process (A) or by 24.7% of process (B) and reduced the soft-water consumption by 38.0% of both (A) and (B).