Analysis of separation of A water-methanol-formaldehyde mixture

Ljudmila Fele Žilnik*

National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia

Janvit Golob

Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana, Slovenia


Vacuum distillation of methanol from aqueous formaldehyde solution is an important step in the production of formaldehyde by the silver process. In this work the separation of this reactive ternary mixture is discussed. The physico-chemical phase equilibrium model proposed by Maurer was used in order to investigate the influence of some operating parameters on the performance of the column. The overall column efficiency was determined and compared with the efficiencies obtained from hydrodynamic conditions. The residence times of the liquid on actual trays were compared with reaction times of the most important chemical reactions in aqueous and methanolic formaldehyde solutions.