高钠煤燃烧利用现状

Situation of Combustion Utilization of High Sodium Coal

对高钠煤燃烧利用现状进行了综述。根据萃取方式,煤中钠的存在形式可分为水溶性钠、酸溶性钠和不可溶钠。介绍了煤阶、显微组分和氯对煤中钠存在形式的影响,概括燃烧过程中煤中钠的迁移规律及其影响因素。在燃烧前期煤中钠可在不同存在形式之间转化,并在燃烧后期由煤中释放出来。阐明了高钠煤燃烧利用过程中的沾污机理:释放到烟气中的钠冷凝在换热面管壁上,并与烟气中物质化合形成硫酸盐,由此造成的沾污是黏结性积灰和高温腐蚀综合作用的结果。最后,结合高钠煤沾污的特点,概述了高钠煤燃烧利用过程中防止沾污与积灰的方法,并讨论潜在的高钠煤提质技术。

A review of the previous research on higher sodium coal combustion technologies was presented in the paper. According to the extraction procedure, the sodium in coal can be divided into water-soluble sodium, acid-soluble sodium and insoluble sodium and the effects of coal rank, maceral and chlorine on the existence form of sodium were also introduced. Furthermore, the conversion rule of the sodium in coal during the combustion process was summarized. The forms of sodium in coal transforms each other in early stage of combustion and are released in the later stage of combustion. The fouling mechanisms caused by sodium during the coal combustion process can be illustrated as follows： the vaporized sodium at high temperature will condense 9n water wall and react with the substance in flue gas to form sulphates. The fouling and deposition during the coal combustion should be the comprehensive result of the high-temperature sintering deposition and corrosion due to the sulphates. Finally, the current control technologies for the high sodium coal fouling and deposition were briefly introduced and some potentially promising research topics on the upgrading of the high sodium coal were discussed.