Release and Transformation Behaviors of Sodium, Calcium, and Iron during Oxy-fuel Combustion of Zhundong Coals

作者：Chang’an Wang, Lei Zhao, Tao Han, Wufeng Chen, Yu Yan, Xi Jin, Defu Che · 发表于：Energy & Fuels · 年份：2017 · DOI：10.1021/acs.energyfuels.7b03200 · 被引用次数：53 · 研究领域：Coal and Its By-products、Coal Properties and Utilization、Thermochemical Biomass Conversion Processes

Zhundong coal has attracted an increasing concern due to its super huge reserve but high content of alkali metals. Oxy-fuel combustion of Zhundong coal benefits the near-zero emission of pollutants in coal-fired power plants and promotes the large-scale utilization of high-alkali coal. However, few efforts if any have been conducted on oxy-fuel combustion of Zhundong coal. The previous studies related to Zhundong coal were mainly focused on sodium behaviors but little work has been performed on calcium and iron, while calcium and iron are very likely to generate significant influences on fouling problems in combustion of Zhundong coal. The present study aimed to elucidate the release and transformation behaviors of sodium, calcium, and iron in oxy-fuel combustion of Zhundong coal using a fixed-bed reactor. Experimental results indicated that calcium in Zhundong coal was mainly present as the ammonium acetate-soluble form, while the iron existed in forms of hydrochloric acid-soluble and insoluble. With the increasing combustion temperature, the ash yields of Zhundong coals decreased and the volatilization ratio of sodium increased, while the temperature had a weak influence on ash yield and the release of water-soluble sodium between 800 and 1000 °C. The variations of total calcium with combustion temperature were not significant, but transformations among various chemical forms occurred. The decreased iron of the hydrochloric acid-soluble form was transformed into the insolub...