Study On The Process Technology Of Lower Alcohol Separation

Lower alcohols are mainly monohydric alcohol with carbon atom number less than six; they are the basic raw materials for synthetic inks, resins, plasticizers, and other fine chemicals. The derivatives of lower alcohols are well-known for high additional value, playing a vital role in the fields of synthetic materials, medicine, paper-making, food, machinery and agriculture. However, most of lower alcohols tend to form binary azeotrope with the water formed or used in the producing of lower alcohols, this makes it difficult to acquire pure alcohol products. In order to solve this difficulty, we develop the new composite dehydrant (DMSO+NMP), according to the physical property of lower alcohol–water system, and on the basis of above research, we develop lower alcohol separation process technology using the product of acetic acid ester hydrogenation.The new composite dehydrant has the high selectivity of DMSO and good solution capacity of NMP, the mass ratio of DMSO and NMP is7:3. Both the simulation result of lower alcohol dehydrating process by Aspen Plus and the experimental data show that, under the conditions of experiment, the dehydration rate of lower alcohol using the new composite dehydrant is10%higher than single dehydrant. What’s more, it can be also used to separate lower alcohol manufactured in different synthetic routes, the containing water can be removed at one time.As to the lower alcohol separation process technology, we make use of the composite dehydrant to get rid of the water, pressure swing operation to remove acetic ester and other impurities. Using this process to separate raw, we can get methanol, ethanol and propanol products conforming to the national standards, the yield also can reach94.7%、99.8%and97.1%, respectively. By using pressure-swing operation, we integrate the heat of the distillation system, after integation, the consumption of the heating utility can reduce by33%, energy saving is remarkable.