Study On Purifying High Boiling Point Compound By Molecular Distillation And Mathematics Model

With the development of commodity, light industry, pharmacy and external trade, the demand for nature material is increased more and more. However, for some high boiling point compounds, it is easy to happen molecule reset, oxidation, hydrolyze and polymerization reaction in orthodox distillation process. The technology of molecular distillation(MD) is an effective natural material purification method, and especially suitable for separating many substances that have the following characteristics, such as: low volatility, high molecular weight, high boiling point, high viscosity, heat sensitivity and biological activity. The MD technology can separate different mixtures under different pressures and can also eliminate odour, pigment ingredient, thereby it can improve the quality of nature products.The key purpose of this thesis is to study the purification of two solid-state products by wiped film molecular distillation apparatus. The experiments of refining rose oil and PolyTHF have been investigated. The effects of the operating parameters on the purity and yield were studied. The optimum process conditions of refining these two products were obtained. This study established the foundation for purification these two products by MD method in the future industry manufacture process.The thermo-sensitivity of rose oil has been studied for it owns high evaporating temperature and solid-state under normal temperatures. Then, the effects of evaporating temperature, operating pressure, feeding flow rate on product purification by MD process have been explored, in which process rational levels and facts for orthogonal optimum were obtained. Meanwhile, a feasible study has been done on the application of molecular distillation to purifying PolyTHF, which has a high boiling point and is also solid-state under normal temperatures. In the fractionation process, the effects of feed flow rate, feed temperature, evaporation temperature, evaporation pressure, agitating speed and separation stages on the purification efficiency were investigated. An optimal combination between concentration and recovery yield of PolyTHF has been obtained.The flow process of the liquid thin-film on the surface of the evaporator has been analyzed. The recycle tubular flow with equal space time model has firstly been used in the simulation of wiped film molecular distillation process by properly simplification to the evaporation process on the evaporator surface. With the theory of...