磷酸二氢钾生产装置氯化铵结晶体系稳定运行优化技术

Optimization technology for stable operation of ammonium chloride crystal system in potassium dihydrogen phosphate production plant

云南云天化红磷化工有限公司3万t/a磷酸二氢钾生产装置系采用有机溶剂萃取法生产磷酸二氢钾,氯化铵是生产磷酸二氢钾的副产物,主要用于肥料及添加剂。从氯化铵结晶装置的运行情况来看,氯化铵结晶系统每运行10 d左右,就得停车对系统内的母液进行油水分离、升温溶解、过滤处理,每次处理时间需要4~6 d,致使装置开车率低,成为磷酸二氢钾装置长周期稳定运行的制约因素。为延长氯化铵结晶体系稳定运行周期,从氯化铵原液的品质、离心机滤网与推料面的间隙、离心机滤网规格、氯化铵结晶器高位溢流管、氯化铵母液的细晶消除等方面提出了优化及改进措施。通过改进,氯化铵结晶体系得以稳定运行,磷酸二氢钾生产装置月开车率由40%~50%上升至75%以上。

The 30000 t/a potassium dihydrogen phosphate production plant of Yunnan Yuntianhua Honglin Chemical Co.,Ltd.adopts organic solvent extraction method to produce potassium dihydrogen phosphate.Ammonium chloride is a byproduct of the production of potassium dihydrogen phosphate and is mainly used as fertilizer and additive.According to the operation of the ammonium chloride crystal plant,it is necessary to stop the plant every 10 d or so to conduct oil-water separation,heating and dissolution and filtration treatment of the mother liquor in the system,and each treatment time needs 4~6 d,which results in low operation rate of the plant and becomes a constraint factor for the long-term stable operation of the potassium dihydrogen phosphate plant.In order to prolong the stable operation period of ammonium chloride crystal system,the optimization and improvement measures were put forward from the aspects of the quality of ammonium chloride stock solution,the clearance between the filter screen and the pushing plate of the centrifuge,the filter screen specification,the high overflow pipe of the ammonium chloride crystallizer and the elimination of fine crystal of ammonium chloride mother liquor.Through improvement,the ammonium chloride crystal system can run stably,and the monthly operation rate of potassium dihydrogen phosphate production plant increases from 40%~50%to over 75%.