Design of a process for the provision of methanolic formaldehyde solutions of low water content from aqueous formaldehyde solutions

Formaldehyde is an essential and widely used intermediate in the chemical industry. It is mostly handled and stored in aqueous solutions. However, some processes require methanolic formaldehyde solutions of low water content as feedstock, among them the production of the synthetic fuel poly(oxymethylene) dimethyl ether (OME). This work presents the conceptual design for a process to provide methanolic formaldehyde solutions with high yield, avoiding aqueous solution as a side product. The separation of water is achieved by a combination of thin-film evaporation and distillation. Process simulations and optimal operating points with respect to energy demand and residual water content are determined. A residual water content of 0.09 g/g in the product could not be undercut.