Recovery of acetone, ethyl alcohol and butanol from their aqueous solution by distillation

摘要

The aqueous solution containing ethanol, butanol and acetone is introduced into a stripping column where the organic compounds in the solution are completely vaporized; the vapours are fed at an intermediate point into a second column from the head of which acetone is withdrawn while aqueous butanol is withdrawn at the base; a liquid mixture of ethanol, acetone and water is withdrawn from the second column at a point between the head and the feed inlet, and this liquid mixture is introduced into a third column from the head of which acetone with only traces of ethanol is withdrawn, while aqueous ethanol containing some acetone, is withdrawn at the base. Some acetone may be withdrawn as a hot liquid free from carbon dioxide from near the head of the second column. The acetone with traces of ethanol withdrawn from the head of the third column may be passed to the top part of the second column. The aqueous butanol withdrawn from the base of the second column may be cooled and passed to a separator; the aqueous layer may then be passed to the stripping column while the butanol layer is dehydrated in a fourth column. In an example, a fermented liquor containing 2 per cent total solvents (comprised of 65 per cent butanol, 4 per cent ethanol, and 31 per cent acetone) is introduced into the head of the first column which is maintained at 193-198 DEG F. The vapours leaving this column are fed into the second column near the middle, a temperature of 180 DEG F. being maintained one-third the way between the middle and head of the column. Acetone is withdrawn from the head, and aqueous butanol from the base, of this second column, and a liquid mixture consisting of 80 per cent acetone, 6 per cent ethanol and 14 per cent water, is taken off midway between the head and the middle of the column. This liquid mixture is introduced into the third column where a head-temperature of 133 DEG F. is maintained. Acetone is withdrawn from the head of this third column, and the base product consists of 30 per cent ethanol, 10 per cent acetone, and 60 per cent water.