对羟基左旋苯甘氨酸三效热泵蒸发结晶工艺的开发研究

Development research on triple-effect heat-pump falling-film evaporative crystallization technology of D-p-hydroxyphenylglycine

分析了对羟基左旋苯甘氨酸母液浓缩结晶过程存在的问题,介绍了三效热泵蒸发结晶工艺。该工艺采用三效并流流程,利用降膜蒸发器、热泵技术进行低温真空蒸发操作。充分利用了一效蒸发器产生的二次蒸汽,新工艺汽水蒸发比降至0.35t/t,左旋苯甘氨酸产量提高约50%。三效热泵蒸发工艺适用于物料处理量大、沸点升高小、蒸发温度低的物料的浓缩结晶。

The problems which existed in the D-p-hydroxyphenylglycine concentrative crystallization process are analyzed. The triple-effect heat-pump falling-film evaporative crystallization technology used in the preparation of D-p- hydroxyphenylglycine is introduced. The triple-effect co-current flow process is adopted. The evaporation process is accomplished under low-temperature and vacuum conditions with falling-film evaporators and heat-pumps technology. The secondary steam from the first-effect evaporator is sufficiently utilized, and the evaporative ratio of steam to water is reduced to 0.35 t/t,and the production is improved by 50%. The technology can be used in the process when the amount of concentrative liquid is large, change of raised boiling point is small and evaporation temperature is low.