Effects of Mineral Transformations on the Reduction of PM_2.5 during the Combustion of Coal Blends

Abstract:

Two chinese bituminous coals used in coal-fired power plants are combusted under air conditions in a lab-scale drop tube furnace. The effects of minerals transformation on the formation of PM _2.5 are investigated during the combustion of coal blends. The collected PM were subjected to Computer controlled scanning electron microscopy (CCSEM) and High-resolution transmission electron microscopy(HRTEM) coupled with energy dispersive X-ray spectroscopy (EDX) analysis for determination of chemical species within them. The results show that PM _2.5 emissions are not linearly related to the wt.% of the parent coal or coal blends. Transformations of fine Si-Al mineral grains provided by the minerals in coal XQ into coarse particles (>2.5 μm in diameter) are responsible for the reduction of PM_1-2.5 during the combustion of coal blending. The transformed fine Si-Al particles are captured by the coarse Ca-Mg-Al-Si provided by the minerals in coal HT to form larger Ca-Mg-Al-Si particles (>2.5 μm in diameter). Increasing Ca and Mg concentration in coal blends enhances the liquid concentration produced during combustion and hence affects the emissions of PM1 and PM_1-2.5.Through adjusting the mineral compositions in coal blends, the reduction of PM1 and PM_1-2.5 emissions can be achieved during combustion.

• Periodical: Advanced Materials Research (Volumes 356-360)
• Pages: 1306-1314
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.356-360.1306
• Online since: October 2011
• Authors: Ming Jun Ji, Yoshihiko Ninomiya, Zhong Bing Dong, Qun Ying Wang
• Keywords: Coal Blend, Mineral Transformations, PM_2.5

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