Abstract:
The predicted reserves of Zhundong coal in the Xinjiang region of China are estimated to be as high as 390 billion tons. However, the high ash slagging and fouling propensities have hindered its safe and economic utilization. To reveal the mechanisms of slagging and fouling and promote high proportion or pure combustion of Zhundong coal, the inorganic constituents in Zhundong coal, the ash formation and deposition characteristics, behavior of ash fouling and slagging in coal-fired boilers as well as the relevant prevention and countermeasures are reviewed. The release and condensation of alkali metal as well as the formation of low-melting-point components are the main culprits for deposit formation. Decreasing the flue gas temperature at furnace outlet, optimizing the arrangement of heat exchange surfaces, and improving soot-blowing methods are the current mainstream furnace design approaches. Strategies at present for managing these problems include coal blending, additive utilization and combustion adjustments. Developing and improving new furnace designs and technological methods hold promise for pure combustion of Zhundong. However, it is also essential to address the new challenges that may arise during flexible and low-carbon development of power plant boilers.