Experimental Investigation into Ash Deposition and Na Migration Characteristics during Combustion of High Sodium Zhundong Lignite in a Circulating Fluidized Bed Operating at Low Temperatures
Experimental Investigation into Ash Deposition and Na Migration Characteristics during Combustion of High Sodium Zhundong Lignite in a Circulating Fluidized Bed Operating at Low Temperatures
复制标题
高钠准东褐煤低温循环流化床燃烧灰分及钠迁移特性实验研究
DOI：
10.1021/acs.energyfuels.9b03413
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发表时间：
2020
期刊：
影响因子：
5.3
通讯作者：
Zhan Dongke
中科院分区：
文献类型：
--
作者：
Liu Zhuo;Li Jianbo;Zhu Mingming;Wang Fei;Lu Xiaofeng;Zhang Zhezi;Zhan Dongke
研究了准东褐煤（<3 mm）在0.2 t d - 1循环流化床（CFB）中较低温度（800 ~ 760℃和750 ~ 680℃）燃烧过程中灰渣的矿物学、形态和化学特征。在炉内稀相（P1）和旋风分离器出口（P2）分别安装了两个风冷探头来模拟灰沉降。利用扫描电子显微镜、x射线能谱、x射线衍射、电感耦合等离子体发射光谱等方法对沉积物以及底灰和飞灰进行了收集和分析。结果表明，p1沉积在800℃时由熔融的Ca/Na硫酸盐颗粒组成，在750℃时变为粒状的Na/Ca/Mg铝硅酸盐颗粒。同样，p2沉积层在800°C时由富含na2so4和caso4的团聚颗粒组成，但在750°C时变为离散的na2so4和NaCl颗粒。在800℃时，底灰富集了（Ca,Na）（Si,Al） 4o8和Na2SO4，在750℃时，底灰转化为Na2SO4， （Na，K）（Si3Al） o8。750℃时，底灰中Na含量由31.3 mg g-1增加到36.5 mg g-1，保留了较多的Na。粉煤灰在na2so4和NaCl中富集，成为离散颗粒。因此，750 ~ 680℃的循环流化床燃烧降低了Na的释放和灰颗粒的烧结倾向，从而降低了灰颗粒的沉积倾向。
The mineralogical, morphological, and chemical characteristics of ash deposits during combustion of Zhundong lignite (<3 mm) in a 0.2 t d–1circulating fluidized bed (CFB) operating at relatively low temperatures, that is, 800–760 and 750–680 °C, were investigated. Two air-cooled probes were installed in the furnace dilute phase (P1) and the cyclone outlet (P2) to simulate ash deposition. The deposits along with the bottom ash and fly ash were collected and analyzed by using scanning electron microscopy energy-dispersive X-ray spectroscopy, X-ray diffraction, and inductively coupled plasma optical emission spectroscopy. Results showed that the P1deposit composed of melted Ca/Na sulfate particles at 800 °C but became granular Na/Ca/Mg aluminosilicate particles at 750 °C. Likewise, the P2deposit comprised agglomerated particles rich in Na2SO4and CaSO4at 800 °C but became discrete Na2SO4and NaCl particles at 750 °C. The bottom ash was enriched with (Ca,Na)(Si,Al)4O8and Na2SO4at 800 °C but turned into Na2SO4, (Na,K)(Si3Al)O8at 750 °C. The Na content in the bottom ash correspondingly increased from 31.3 to 36.5 mg g–1, retaining more Na in the bottom ash at 750 °C. The fly ash also became discrete particles enriched in Na2SO4and NaCl. The CFB combustion at 750–680 °C thus decreased the release of Na and the sintering propensity of ash particles and consequently lessened their deposition propensity.