响应面法优化水溶性沥青的制备工艺

Preparation of water-soluble pitch by response surface optimization method

以中温煤沥青为原料,浓硫酸和浓硝酸为氧化剂制备水溶性沥青。以水溶性沥青的收率为指标考察反应温度、反应时间、改性剂等因素对其的影响;在单因素实验数据的基础上,应用响应面优化技术对水溶性沥青的制备工艺进行了响应面优化分析,建立了制备水溶性沥青的二阶多项式非线性回归方程和数值模型,分析了反应温度、反应时间、液料比对水溶性沥青制备的影响规律,优化了水溶性沥青的制备工艺。最终得出响应面优化方案为反应温度38.07℃,反应时间7.57 h,硝酸与硫酸的体积比3∶7,液料比22.42 mL/g为最优实验方案。优化条件下验证试验结果产品最高收率是124%。研究还发现,经过产品的水溶性检测,水溶性沥青的溶解性与pH密切相关,随着溶液pH值的增大,水溶性沥青的溶解性增大,实验获得的水溶性沥青能100%溶于pH值为12的碱性溶液。

With the medium coal tar pitch as the raw material, the concentrated sulfuric acid and the nitric acid as the oxidants, the water soluble pitch was obtained. Suitable process conditions were identified by studying the effects of the reaction temperature, the reaction time and the modifier on the yield of water soluble pitch. Based on the single factor inspection, the preparation process of water soluble pitch was optimized using the response surface optimization method, and a nonlinear second-order polynomial re- gression equation and numerical model were established. This equation and model were used for analyzing the influence rules of re- action temperature, reaction time and ratio of liquid on preparation of water soluble pitch and optimizing the preparation process. The results showed that the response surface optimization conditions were the reaction temperature of 38.07 ~C, reaction time of 7.57 h, the ratio of nitric acid to concentrated sulfuric acid of 3：7 （volume） and the ratio of material to liquid of 22.42 mL/g. Under the optimized condition, the highest yield of water soluble pitch was 124%. It is also found that the solubility of water soluble pitch was closely related to the pH, and with the increase of the pH value of the solution, the solubility of water soluble pitch increased and can be completely soluble in alkaline solution with pH value of 12.