碱性氧化物对煤灰熔融特性影响的研究进展  

Research progress on the effect of alkaline oxides on coal ash fusibility

作　　者：王东旭[1] 王洋[1] 李文艳[1] 肖海平[1] 

机构地区：[1]华北电力大学能源动力与机械工程学院,北京102206

出　　处：《化工进展》2017年第B11期167-174,共8页Chemical Industry and Engineering Progress

基　　金：国家科技支撑计划项目(2015BAA04B02)

摘　　要：准东煤中的钠、钙含量较高,导致在燃用过程中锅炉受热面发生严重的结渣。煤灰的结渣问题与煤灰的熔融特性密切相关,灰中碱性氧化物对灰熔融特性具有重要的影响。本文综述了碱性氧化物对煤灰熔融特性的影响。现有的研究表明,添加Na_2O可以显著降低灰熔融温度,钠长石、霞石等低熔点含钠矿物质的生成及其形成的低温共熔体是灰熔融温度降低的主要原因。灰中K_2O主要以伊利石的形式存在,对灰熔融温度的影响较小。随灰中CaO和MgO含量的增加,灰熔融温度具有先降低后升高的变化趋势,矿物质熔点的变化是灰熔融温度变化的主要原因。灰中Fe_2O_3的存在形式与反应气氛有关。在还原性气氛下,铁主要以FeO的形式存在,铁橄榄石、铁尖晶石等含铁矿物质容易形成低温共熔体,使灰熔融温度降低。未来应着重研究碱性氧化物对准东煤灰熔融特性影响的机理,开发抑制准东煤结渣的高效添加剂。The high contents of sodium and calcium in Zhundong coal induce severe slaggingproblems in boilers＇ heating surfaces durning coal combustion. The slagging of coal ash hasimportant relationship with coal ash fusibility, and the alkaline oxides in coal ash can influencethe ash fusibihiy significantly. Recent progress on the effect of alkaline oxides on coal ashfusibility was summerized. The present studies show that the addition of Na20 can reduce the ashfusion temperatures （AFTs） significantly. The Na containing minerals with low melting pointsuch as albite, nepheline and the eutectics they form is the main reason for reducing theAFTs. K20 mainly exists as illite in ash, the AFTs show no significant change as the K20content varies. The AFTs drop first and rise later with the increase of CaO or MgO content, thechange of minerals~ melting point leads to the change of the AFTs. The existing form of Fe203depends on the reaction atmosphere. The Fe in ash mainly exists as FeO in reducing conditions,Fe-containing minerals such as fayalite and hercynite can easily form eutectics thus reducing theAFTs. Further studies should be focused on the effect of alkaline oxides on the ash fusibility ofZhundong coal, to produce novel additives for resisting the slagging problems efficiently.

关 键 词：煤燃烧 灰熔融特性 碱性氧化物 准东煤 结渣 沉积物 

分 类 号：TK536.4[动力工程及工程热物理—热能工程]