Device assembly and method for purifying dimethyl ether in biomass by rectification

The invention discloses a device assembly for purifying dimethyl ether in biomass by rectification. The device assembly mainly comprises a pre-rectifying tower, a primary rectifying tower, corresponding rectifying unit auxiliary equipment and a heating-cooling system; dimethyl ether is purified through pressure rectification and fractional separation; multiple layers of fillers or tower plates are horizontally distributed in the rectifying tower in parallel so that gas-liquid heat and mass transfer is performed. According to the invention, optimization and integration are realized by virtue of a traditional chemical engineering unit; by combining composition characteristics of dimethyl ether produced by biomass, based on experimental data, the device assembly overcomes the technical difficulty in purification of dimethyl ether in biomass; meanwhile, the device assembly can be massively applied to a commercial system for separating dimethyl ether from biomass, thus promoting commercial operation of one-step dimethyl ether catalyzing synthesis. The invention also discloses a method for purifying dimethyl ether in biomass by rectification by virtue of the device assembly for purifying dimethyl ether in biomass by rectification.