The invention discloses a method of recovering
formaldehyde from a supercritical method prenyl
alcohol synthesis system. According to the method,
formaldehyde-containing 3-
alcohol crude product which is obtained by supercritical reactions is subjected to continuous rectification under a normal pressure;
formaldehyde and a little of 3-
alcohol are directly produced from the
tower top; formaldehyde is enriched continuously and carries out self-
polymerization to form
polymer (
solid) adhered on the internal wall of a condenser; then the formaldehyde
polymer is separated by a scraper and a cold filtering method; and 3-alcohol obtained by
tower top filtering and 3-alcohol in the
tower bottom are dehydrated, weight-reduced, and rectified to carry out purification. By adopting the method, the formaldehyde content of 3-alcohol crude product can be reduced to less than 0.01%, the product becomes qualified, at the same time, the recovered formaldehyde
polymer can be used as a
raw material, and the waste is converted into valuable resource. The technology can remove formaldehyde without adding any alkaline chemical
reagent, the cost is saved, and the discharged
wastewater is greatly reduced. The method is green and environmentally-friendly, has a lower cost, and can be widely used in industry.