Study On The Melt Crystallization Separation Process And CFD Simulation Of P-Cresol

P-cresol is an important organic chemical raw material. Being further processed, it could produce a series of derivatives. P-cresol and its derivatives are widely used in medicine, agriculture chemicals, dyestuff, spice, cosmetics, food and polymer material etc. Recently, needs for high-purity p-cresol are rising in both international and domestic markets. Therefore, the separation and purification of coarse p-cresol call for a high attention.Nowadays, fractional melt crystallization is the most popular method to produce high-purity p-cresol. Meanwhile, based on the melt crystallization, new operation processes are been developed continuously to improve the effectiveness of the method. The most prominent operation is bullet-like pulse aeration.Based on the former researches, experimental facility is designed and built. Melt crystallization experiments of p-cresol are conducted in different operating conditions, they are static, continuous aeration and pulse aeration. The advantages and weakness are showed by comparing and analyzing the experimental results.Further, a novel research tool, computational fluid dynamics (CFD), is used to investigate the gas-liquid flow caused by the pulse bubbles. Divided by the flow pattern, the rising of pulse bubbles in the p-cresol melt is classic slug flow. According to its characteristics, reasonable assumptions are made, and mathematic models are built on the basic two-phase model and turbulent model.Using the model above, the numerical simulation of nitrogen-p-cresol melt two-phase flow is calculated by the CFD software Fluent. By analyzing the phase distributions, dynamic pressure fields and velocity fields provided by the calculation results, the bullet-like bubble flow's favorable effects on the melt crystallization are explained qualitatively. In the end, further research expectations are put forward.