Exploration of efficient utilization of high-alkali coal based on combustion process and combustion parameter optimization

•The slagging mechanism of high alkali coals is reviewed.•Summarized the efficient utilization method of pure high-alkali coal.•Summarizes the practical applications of relevant research and the bottlenecks.•Certain suggestions are made for the utilization of high-alkali coal. High-alkali coal is a type of coal that is widely spread around the world; the combustion of high-alkali coal in a boiler can lead to severe slagging and negatively impact boiler safety because of the large quantities of alkali metals and alkaline earth metals (AAEMs) present in this type of coal. The discovery of a large amount of high-alkali coal in the Zhundong region of Xinjiang, China, with enormous reserves for long-term use, makes the optimized utilization of high-alkali coal of great significance. In this paper, we review the combustion methods like circulating fluidized bed (CFB) combustion, oxy-fuel combustion, and slag-tapping cyclone furnace to optimize the combustion methods and combustion parameters of conventional boilers, analyze how these technical methods can alleviate the slagging and ash accumulation of high-alkali coal, and point out some technical shortcomings of these methods and Current status of research on related issues. Finally, based on the existing research status, several suggestions and future research directions are proposed to realize the industrial application of pure high-alkali coal.