Study On The Process Of Molecular Distillation Using GPROMS

Molecular distillation technology can solve lots of problems that conventional distillation is unable to, it also has many advantages such as separation of materials with high boiling point, heat sensitive, readily oxidable. It can well protect the quality of the product. Presently, molecular distillation technology is widely used for the separation of products in many industries.During the process of molecular distillation, the temperature and concentration on the surface of the film are difficult to measure. If the evaporating rate is caculated using the temperatures and concentrations at the wall and in the film body, the result will greatly differ from the actual ones. Therefore, the key parameters at the surface are gained mainly by simulation. The model for molecular distillation involved, fluid dynamics, heat transfer and mass transfer. To describe these issues, series of partial differential equations are often employed. Except for some simple instances, it is difficult to get the analytical solution of these partial differential equations.Equation oreiented approach is employed in gPROMS to solve complex problems. gPROMS provides advanced modeling environment and can easily solve the dynamic and distribution model. gPROMS is a new method to study molecular distillation.Glyserol, which contains fatty acid methyl ester, is a industrial chemical which is produced as a by product during the production of biodiesel. If glycerol is recovered and utilized, it will preserve the resources and reduce the price of biodiesel.After studying the wiped film molecular distillation process, mathematic model of mass and heat transfer is established. gPROMS is employed to solve the process model of separating glycerol and methyl oleate. The optimum conditions are as follows, temperature, 378K, wiper rotation rate, 300rpm and feed rate, 0.09g/s.Experiments were carried out to verify the reliability of the model and solution. Evaporating wall temperature, wiper rotation rate and feed rate have effects on evaporating rate, yield of glycerol and purity. The trends of experimental results and calculations are in good agreement. The wiped film molecular distillation mathematical model and its solution are reliable.This study will improve the wiped film molecular distillation model, designing of molecular distillator and promote the molecular distillation technology.