52results about How to "No recycling issues" patented technology

The invention relates to a method for separating dimethyl carbonate methanol azeotrope through melt crystallization and application thereof. The method specifically comprises the following steps: introducing a dimethyl carbonate methanol azeotrope with the dimethyl carbonate content of 25-35% into a melt crystallization device, separating out dimethyl carbonate in a crystal form through cooling, then partially melting dimethyl carbonate crystals through heating sweating, removing impurities contained in the crystallization process, further purifying dimethyl carbonate, and finally obtaining ahigh-purity dimethyl carbonate product and a low-concentration crystallization mother solution. The crystallization temperature of dimethyl carbonate in a self-azeotropic system is -20 to -40 DEG C, and the operation equilibrium temperature of a crystallization section is -50 to -60 DEG C, the purity of the dimethyl carbonate product is 99.9%-99.999%, and the concentration of the crystallization mother solution is 5%-15%. The method can be used for separation and purification of dimethyl carbonate methanol azeotropic composition in the process of producing dimethyl carbonate by a synthesis method or producing dimethyl carbonate as a byproduct in the coal-to-ethylene glycol process, and has the advantages of low energy consumption, high product purity and the like compared with traditionalseparation modes such as pressurized distillation, extractive distillation or azeotropic distillation.

A method for preparing chitosan oligosaccharides through semi-wet method microwave treatment relates to a production method of chitosan oligosaccharides. The method comprises the following steps: using chitosan gelatine powder as raw material to perform hydration and microwave treatment, dissolving in water, neutralizing, and performing membrane separation, drying and the like to prepare chitosanoligosaccharides. The method does not consume organic solvent, thus the problem of recycling solvent does not exist and the pollution is low; and as the volume of the reaction system is from 1 / 3 to 1 / 5 of that of the solution method, the production efficiency is obivously increased. The method adopts microwave treatment to promote the polysaccharide degradation reaction, thus the heating effect is greatly increased. The radiation thermal effect of microwave and the non-thermal effect of microwave are utilized to prepare the product. Meanwhile, microwave is an efficient and clean energy, thus the speed of the chemical reaction can be greatly increased. The method also adopts the membrane separation mean, thus the refining efficiency is high and the product quality is controllable.