Abstract: Reduction of gaseous KCl producing in biomass combustion can help eliminate corrosion and ash deposition on the heating surface. Reaction characteristics of gaseous KCl and ammonium dihydrogen phosphate (ADP) are studied by using chemical thermal equilibrium analysis,including the effect of temperature and stoichiometric ratio. The simulation results show that gaseous KCl can be effectively transformed into K₂HPO₄ in a temperature range of 700—950℃. The reaction products obtained in the experiment using drop tube furnace system are analyzed by X-ray diffraction to examine the effects of mole ratio of P/K (α), residence time and temperature on KCl removal by ADP. The experimental results show that prolonging reaction time and increasing P/K mole ratio can promote conversion of gaseous KCl. At the experimental conditions: the temperature range of 700—1000℃, mole ratio of P/K of 1, residence time of 3 s, there is no KCl in the products (not detected by XRD). That means that KCl has be effectively transformed into dipotassium hydrogen phosphate (K₂HPO₄), potassium dihydrogen phosphate (KH₂PO₄), potassium metaphosphate[(KPO₃)_n], potassium pyrophosphate (K₄P₂O₇), potassium ammonium phosphate, potassium-ammonium dihydrogen phosphate etc. These results will be helpful for further study removing gaseous alkali metal ions by ammonium dihydrogen phosphate.

Key words: biomass, combustion, KCl, ammonium dihydrogen phosphate, removal

摘要： 脱除生物质燃烧中气相氯化钾，有助于消除受热面的积灰和腐蚀。采用热力学化学平衡分析方法探索了磷酸二氢铵脱除气相氯化钾的反应特性，考察了温度和化学计量比对反应的影响，结果表明磷酸二氢铵在700～950℃范围内可以有效地将气相氯化钾主要转化为磷酸氢二钾。利用X射线衍射分析对沉降炉实验得到的反应产物进行物相分析，探索了磷钾摩尔比、停留时间、温度对磷酸二氢铵脱除氯化钾的影响，实验结果表明增加停留时间以及磷钾摩尔比均可以促进KCl的脱除，停留时间3 s，磷钾摩尔比为1时，700～1000℃下的反应产物中未检测到物相KCl，而生成了磷酸氢二钾、磷酸二氢钾、偏磷酸钾、焦磷酸钾、磷酸钾铵、磷酸二氢铵钾等产物。结果有助于深入研究磷酸二氢铵用于脱除燃烧中碱金属离子。

关键词: 生物质, 燃烧, 氯化钾, 磷酸二氢铵, 脱除