城市污水污泥与麦秆混烧过程中钾的转化特性

Behavior of Potassium During Co-Combustion of Municipal Sewage Sludge With Wheat Straw

采用立式管式炉试验系统研究城市污水污泥与麦秆混烧过程中碱金属钾的转化特性,利用电感耦合等离子体发射光谱仪(ICP-OES)、X射线衍射仪(XRD)以及扫描电子显微镜(SEM)等检测手段,分析麦秆和城市污水污泥不同温度混烧灰的成分、晶相结构以及微观形貌。研究结果表明,700℃和800℃时,麦秆底灰中钾主要以KCl和K_2SO_4形态存在,900℃时则以K_2SO_4形态存在;温度对城市污水污泥底灰以及混烧底灰中钾的赋存形态影响很小,城市污水污泥底灰中钾主要以KAlSi3O8形式存在,城市污水污泥与麦秆混烧底灰中钾除了以KAlSi_2O_6、KAISi_3O_8形式存在外,还存在高熔点的碱金属磷酸盐化合物Ca_9MgK(PO_4)_7。

The behavior of potassium during co-combustion of municipal sewage sludge with wheat straw was investigated in a vertical tubular furnace reactor.The elements content,phase component and microstructure of the ash samples were characterized with inductive coupled plasma equipped with an optical emission spectrometer（ICP-OES）,X-ray diffractometry（XRD） and scanning electron microscopy（SEM）,respectively.The results showed that：at 700℃and 800℃,potassium in the wheat straw ash is mainly in the forms of KC1 and K_2SO_4 while at 900℃mainly in the form of K_2SO_4. The temperature has little effect on the sewage sludge bottom ash and the mixed bottom ash.Potassium in the sewage sludge ash is mainly in the form of KAISi_3O_8.In the ash samples of co-combustion of municipal sewage sludge and wheat straw,potassium is in the form of potassium-alumino-silicates （KAISi_2O_6,KAISi_3O_8）,and high-temperature melting potassium phosphates Ca_9MgK（P_4）_7.