多级逆流水洗法回收催化气化灰渣中的钾催化剂

Recovery of Potassium Catalyst from Coal Gasification Ash Using Multistage Counter-current Water Washing Method

采用逆流水洗法将1 t/d煤催化气化工艺过程开发装置(PDU)稳态排放灰渣中的水溶性钾进行回收。研究了六级逆流水洗操作对灰渣中钾催化剂的回收效果,并考察了水洗液中钾含量对灰渣中钾析出效果的影响。结果表明:灰渣中可溶性钾与总钾质量比为62%,采用不同水洗工艺可将可溶性钾全部回收,单级逆流水洗工艺和六级逆流水洗工艺的耗水量分别为灰渣质量的6倍和不到3倍。因此,六级逆流水洗耗水量远低于单级逆流水洗工艺耗水量,不仅达到节水的目的,还可降低后续浓缩工段能耗。催化剂溶液的最高富集浓度为30%(质量分数),可输送至催化剂负载单元进行循环利用。

The water-soluble potassium catalysts in the ash residue were recovered from the 1 t/d process development unit gasifier(PDU)by using the multistage counter-current water washing method.The effects of the six-stage counter-current water washing operation on the catalyst recovery were studied,and the effects of the mass fraction of potassium in the solution on the dissolution of the potassium recovered from the coal ash were also investigated.The results show that the water consumption of the six-stage counter-current water washing process is far lower than that of the single-stage process.Reached the same potassium recovery of 62%,water consumption of one-stage process and six-stage counter-current water washing process is 6 times and lower than 3 times the amount of ash residue,respectively.Furthermore,the proposed six-stage process can also decrease the energy consumption for the evaporation and concentration of the catalyst solution.The maximum enriched concentration of the potassium in the catalyst recovery solution is 30%(mass fraction),which can be cycled to the catalyst impregnation unit.