咖啡因分段结晶工艺研究

Study on the Technology of Caffeine′s Piecewise Crystallization

基于咖啡因生产能耗高、产品晶型较差的现状,进行了分段结晶的实验研究,并确定了最佳工艺条件,同时测定了50～80℃时咖啡因在水中的溶解度及一定条件下的超溶解度,得到了相应的二次拟合方程。结果表明:一段结晶的最佳工艺条件为降温速率0.05℃.min-1、转速250r.min-1、48.2℃下抽滤;二段结晶的最佳工艺条件为降温速率0.04℃.min-1、转速250r.min-1、37.4℃下抽滤。一段结晶后溶液的质量浓度由10.71%降至6.99%,二段结晶后质量浓度进一步降至3.47%。通过软件模拟分析,分段结晶比一次冷却结晶能耗降低约18%。

Considering the problems of the small product＇s grain and the high energy consumption in current caffeine industry,the caffeiners piecewise crystallization was proposed. The optimum process conditions were obtained,and the solubility of caffeine ＇was rneasured at 50-80 °C, the super solubility under certain conditions was measured also, and the corresponding quadratic regression equations were obtained. The optimum condi- tions based on crystal were determined as follows：the first stage of crystallization was at 0.05 ＊C ~ min-1 and 250 r · min^-1 ,leaching at 48.2 °C ,the second stage of crystallization was at 0.04 °C · min^-1 and 250 r ·min ^-1, leaching at 37.4 °C. The concentration reduced from 10.71% to 6.99% and to 3.47% furtherly. Through soft ware simulation,the energy consumption of piecewise crystallization could be reduced by 18%.