Adsorptive Drying of Liquid Mixtures Containing Formaldehyde, Methanol, Water, and Poly(oxymethylene) Dimethyl Ethers on Zeolite 3A

The separation of water from mixtures containing formaldehyde, methanol, water, and poly(oxymethylene) dimethyl ethers (OME) is a fundamental step in the water-tolerant OME_3-5 production processes. Several approaches have been discussed in the literature, including pervaporation, reactive distillation, and adsorption. This study focuses on the adsorption on zeolite 3A. Building on prior research, we extend an existing equilibrium adsorption model for systems containing formaldehyde + methanol + water to systems containing OME. Experimental data on breakthrough curves of formaldehyde, methanol, and water from a laboratory-scale column are presented. A comprehensive column model, encompassing chemical and adsorption equilibria, adsorption kinetics, and fluid dynamics, accurately predicts the breakthrough curves. The regeneration of the zeolite 3A is shown experimentally. A stream table for a water-tolerant OME_3-5 production process including adsorption is given, showing that water can be separated from mixtures containing formaldehyde, methanol, and OME with a high selectivity.