The Extractive Distillation Continuous Crystallization Integrated Extraction Durene Research

Durene is an important chemical material. Durene may be used as material in medicine, matting agent of coating, coloring matter, agricultural chemical pesticide and surfactant. Pyromellitic dianhydride obtained through oxidization can be polymerized with compounds having two amino groups to produce polyimide, which, being heat-resistant and highly insulating, is an important material in such industries of advanced technology as microelectronics, aeronautics, and war industry. This is durene another important applications. The thesis probes into the extraction of durene from aromatic hydrocarbon by integrated separation technologies:continuous distillation with side draw, extractive distillation with continuous crystallization.Continuous distillation with side draw was simulated by Aspen Plus, influence factors such as outlet plate number, feed stage number, distillate flow rate, reflux ratio and number of theoretical stage on the separation was investigated. An experimental apparatus of side-draw distillation was set up in the experiment according to the data obtained through the simulation. The experimental results showed that the purity of durene was increased from 7.74% to 16.20% with the yield of 86.15% achieved under the condition that number of theoretical stage was 40, feed stage number was 11, side draw stage was 18, and reflux ratio was 3～4, the temperature of top was 185～186℃, the temperature of bottom was 229～231℃, feed flow rate was 0.1L/hr, distillate flow rate was 0.04L/hr, side draw flow rate was 0.04 L/hr.The experimental apparatus of single stage gas-liquid equilibrium was set up, and vapor-liquid equilibrium data of solvent-mixed C10 was measured. The relative volatility of various components was calculated when different solvent was added into raw material and sulfolane was selected as the optimal solvent for extractive distillation.Extractive distillation was simulated by Aspen Plus, influence factors such as distillate flow rate, reflux ratio, solvent ratio and number of theoretical stage were studied. The experimental apparatus of extractive distillation was set up, and experimental study was carried out on the basis of the theoretical data, which was obtained by simulation. The experimental results showed that the purity of durene was increased from 16.20% to 31.06% with the yield of 98.59% under the condition that feed flow rate was 0.1L/hr, distillate flow rate was 0.04L/hr, stripping section was 60cm, extraction section was 70cm, Solvent recovery section was 30cm, solvent ratio was 3 and reflux ratio was 3～5.The raw material containing 31.06% durene, which was got from the extractive distillation apparatus, was put into continuous crystallization apparatus. The crystallization temperature, crystallization time, filtration time that is the important factors of continuous crystallization were investigated. When the crystallization temperature was -6℃, the crystallization time was set at 5hr and the vacuum filtration time was set at 20min, the purity of durene could reach to 99.90% and yield could reach to 92.05%.