Process for the continuous preparation of aqueous formaldehyde solutions

摘要

The process uses a supply column and additional heat exchangers associated with absorption columns. Air and methanol from outside and a subcurrent of methanol, originating from a cold methanol current exiting from the supply column, are fed to the supply column. This exiting current recirculates through the additional heat exchangers and is divided into the subcurrent which returns to the supply column and another subcurrent which is fed to an evaporator. A methanol-air mixture exits from the head of the supply column and is fed to an evaporator. The cold methanol is cooled in the supply column by evaporation of the methanol forming part of the methanol-air mixture.