燃准东煤电站锅炉沾污结渣特性及防治措施研究进展

Research Progress on the Characteristics and Countermeasures of Ash Slagging and Fouling in Boilers Burning Zhundong Coal

新疆地区的准东煤预测储量高达3900亿t,然而煤灰的高沾污结渣倾向严重制约着准东煤在电站锅炉的安全经济利用。为了明晰沾污结渣机理,推动准东煤在电站锅炉的高比例掺烧甚至纯烧,该文从准东煤的无机组分组成、煤的成灰特性、灰的沉积特性、电站锅炉受热面沾污结渣特性和防治措施5个方面对相关基础研究和工业应用情况进行总结。碱金属钠的释放、冷凝和低熔点组分的形成是沾污结渣主要原因,混煤和添加剂的使用以及燃烧调整是最常用的应对措施,降低炉膛出口烟气温度、优化受热面布置和吹灰方式是目前主流的炉型设计思路。开发完善新的炉型和技术手段有望为纯烧准东煤提供解决思路,但还需要应对燃准东煤电站锅炉灵活低碳发展过程的新挑战。

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.