论文部分内容阅读
通过研究3种富磷添加剂与麦秆中碱金属的化学反应机制,分析磷对麦秆燃烧过程中碱金属迁移转化行为的影响。富磷添加剂包括:磷酸二氢铵(NH4H2PO4)、磷酸二氢钙(Ca(H2PO4)2·H2O)、磷酸三钙(Ca3(PO4)2)。利用电感耦合等离子体发射光谱(inductively coupled plasma optical emission spectrometer ICP-OES)、X射线衍射(X-ray powder diffraction,XRD)以及扫描电子显微镜X射线能谱(scanning electron microscopy,energy dispersive X-ray SEM-EDX)等分析检测手段,对燃烧底灰中碱金属(K和Na)含量、产物物相、微观形貌及特征区域元素分布进行分析。在800℃进行麦秆与富磷添加剂的混烧实验。研究结果表明,适量富磷添加剂的添加对麦秆中碱金属具有捕集作用,抑制碱金属以气态形式析出,还可以抑制麦秆底灰发生烧结。富磷添加剂与麦秆中碱金属发生化学反应可生成高熔点K-Ca-P的化合物。NH4H2PO4和Ca(H2PO4)2·H2O与麦秆中碱金属反应主要生成CaK2P2O7;Ca3(PO4)2与麦秆中碱金属反应主要生成Ca10K(PO4)7、Ca10Na(PO4)7和Ca5(PO4)3Cl。碱金属磷酸盐的生成说明了富磷添加剂对麦秆燃烧过程中碱金属捕集作用的机制。
The effects of phosphorus on the migration and conversion of alkali metals in wheat straw during combustion were analyzed by studying the chemical reaction mechanisms of three phosphorus-rich additives with alkali metals in straw. Phosphorus-rich additives include: ammonium dihydrogen phosphate (NH4H2PO4), monocalcium phosphate (Ca (H2PO4) 2 H2O), tricalcium phosphate (Ca3 (PO4) 2). The samples were characterized by inductively coupled plasma optical emission spectrometer (ICP-OES), X-ray powder diffraction (XRD) and scanning electron microscopy -EDX) were used to analyze the content of alkali metals (K and Na), the phases of the products, the micro-topography and the distribution of the elements in the characteristic areas. At 800 ℃ for wheat straw and phosphorus-rich additive mixing experiment. The results showed that the addition of appropriate phosphorus-rich additive had the effect of trapping alkali metal in straw, inhibiting the precipitation of alkali metal in gaseous form, and inhibiting the sintering of bottom ash of wheat straw. Chemical reaction of phosphorus-rich additive with alkali metal in straw can produce compounds with high melting point K-Ca-P. Ca (PO4) 7, Ca10Na (PO4) 7 and Ca5 (PO4) 7 mainly react with alkali metal in wheat straw by reacting NH4H2PO4 and Ca (H2PO4) 2 · H2O with alkali metals in wheat straw. 3Cl. The formation of alkali metal phosphates illustrates the mechanism of phosphorus-rich additives on the trapping of alkali metals in straw during combustion.