Use of pressure swing absorption for water removal from a wet methanol stream

摘要

The present invention includes a process to dry a feed steam containing alcohol and a small quantity of water. The process includes the step of using pressure swing adsorption to produce a first alcohol stream of substantially dehydrated alcohol and a second mixed stream of water and alcohol. The second mixed stream is distilled in a distillation column to produce a relatively purified water stream and a wet alcohol stream. The wet alcohol stream is added to the feed stream. Optionally the present invention is used to recover excess methanol from a biodiesel reactor that uses one or both of the transesterification reaction and the esterification reaction. The biodiesel reactor produces a product stream comprising fatty acid esters, water and alcohol. Water and alcohol is separated from the product stream. The alcohol is dried as noted above. Dried alcohol is recycled to one or both of the transesterification reaction and the esterification reaction.