Role of potassium in deposit formation during wood pellets combustion
Role of potassium in deposit formation during wood pellets combustion
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DOI：
10.1016/j.fuproc.2015.10.008
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发表时间：
2016
影响因子：
7.5
通讯作者：
M. Paneru;S. Babat;J. Maier;G. Scheffknecht
中科院分区：
文献类型：
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作者：
M. Paneru;S. Babat;J. Maier;G. Scheffknecht
关于结渣、结垢和腐蚀的生物质锅炉问题与燃料中存在的碱性物质有关。这些碱性物质在燃烧期间作为气态碱金属氯化物、氢氧化物和/或硫酸盐释放。碱金属氯化物/硫酸盐随后在冷锅炉表面上冷凝，从而增加结垢和腐蚀。富硅灰的后续沉积导致低温熔融共晶的形成，特别是碱金属/碱土金属硅酸盐（K/Ca-Si），并产生致密和坚固的沉积物。冷凝的氯化物/硫酸盐和低熔点共晶体都降低了锅炉的性能和可用性。在本研究中，燃烧了两种不同的木质生物质燃料及其与两种不同的铝硅酸盐基添加剂的混合物。使用两种不同类型的探针对沉积物进行取样;冷却存款探针和未冷却存款探针。利用电子显微图像分析（EMPA）对两个存款样品的宏观和微观观察结果以及化学成分进行了比较。添加剂显著改变了存款样品的形态和组成。形态和组成的差异可以通过两种情况下钾化学的变化来解释。
Biomass boiler issues regarding slagging, fouling and corrosion are related to alkali species present in fuels. These alkali species are released as gaseous alkali chlorides, hydroxides and/or sulfates during combustion. Alkali chlorides/sulfates later condense on cold boiler surfaces enhancing fouling and corrosion. Subsequent deposition of silica-rich ashes leads to the formation of low temperature melting eutectics, especially alkali/earth alkali-silicates (K/Ca-Si), and creates compact and strong deposits. Condensing chlorides/sulfates and low melting eutectics both reduce boiler performance and its availability.Two different woody biomass fuels and their mixture with two different kinds of aluminosilicate base additives were combusted during this study. Deposits were sampled using two different kinds of probes; cooled deposit probe and un-cooled deposit probe. The macroscopic and microscopic observations and chemical composition of deposit samples are compared using electron microscopic image analysis (EMPA) for both deposit samples. The additive significantly changes the morphology and composition of the deposit samples. The difference in morphology and composition can be explained by the change in potassium chemistry between two cases.