CLEANING METHOD OF WASTE WATER FROM ALDOL REACTION AND SUCCEEDING HYDROGENATION REACTION

摘要

PROBLEM TO BE SOLVED: To realize waste water cleaning which enables effective recovery of an extracting agent when waste water originated in each stage of alcohol producing process, by acidifying waste water and then extracting, and then bringing the water into contact with a drop collecting filter. SOLUTION: In the alcohol production process having steps of aldol reaction, hydrogenation and alcohol distillation, various waste water are discharged such as a catalyst-contg. water phase from the aldol reaction, waste water from a refining process of ,-unsatd. aldehyde produced by the aldol reaction, and waste water from a step to refine a distillation residue of alcohol. When the waste water above described is to be purified, the waste water is subjected to extraction with a univalent alcohol having 8 to 16 carbon atoms in the molecule and/or with a hydrocarbon having 6 to 12 carbon atoms in the molecule. In this process, first, the pH of the waste water is controlled to 0 to 6, preferably 1 to 3, and if necessary, the org. phase produced in this stage is separated and removed. Then the waste water is brought into contact with a drop collecting filter to be cleaned.