山西风化煤灰分高、热值低,导致其燃烧发电利用受限。前人大量研究了从风化煤中提取腐植酸及其相关应用,但目前鲜见风化煤灰渣形成特性相关试验研究。为探究山西风化煤的灰渣形成特性,以小型流化床反应器为主要试验装置,对风化煤在不同煤颗粒粒径、燃烧气氛下分别进行热态燃烧试验。利用天平、振动筛、马弗炉、激光粒度仪、X-Ray衍射仪分析风化煤灰渣的份额分布、颗粒特性及矿物含量,揭示了不同燃烧工况下风化煤灰渣形成特性的差异。结果表明:随煤颗粒粒径增加,燃煤颗粒炉内磨损程度减弱,飞灰份额由43.20%降至1.51%,石英、莫来石、赤铁矿生成量和高岭石转化量增加;出口烟气中O2体积分数增加有利于高岭石和黄铁矿转化分解生成石英、莫来石和赤铁矿:随出口O2体积分数由0增至5.16%,风化煤底渣中石英质量分数由41.21%增至51.13%,莫来石质量分数由7.24%增至21.42%,赤铁矿质量分数由6.81%增至23.32%。高灰低热值风化煤能在流化床中实现稳定燃烧,出口烟气中O2体积分数3%~5%时,2~4mm风化煤能保持较高燃烧效率和矿物转化率,有利于燃烧系统稳定高效运行和灰渣二次利用,可作为循环流化床燃料选用依据。

The high ash content and low calorific value of Shanxi weathered coal limit its utilization in combustion and electricity genera⁃tion. Extraction and utilization of humic acid from weathered coal has been extensively studied, but few studies have been conducted on itsash formation characteristics. To study the ash-slag formation characteristics of the weathered coal, a small fluidized bed reactor was usedas the main experimental device to conduct hot combustion tests on weathered coal under different coal particle size and combustion atmos⁃phere. Balance, vibrating screen, muffle furnace, laser analyzer and X-ray diffraction analyzer were used to analyze the slag-ash ratio,particle size distribution and mineral contents, which revealed the differences in the ash-slag formation characteristics of weathered coal.The results show that with the increase of coal particle size, the particle attrition in the furnace is inhibited and the fly ash ratio decreasesfrom 43.20% to 1.51%, and the production of Quartz, Mullite and Hematite content and the conversion of Kaolinite increase. The increaseof oxygen concentration in flue gas promotes the conversion of Kaolinite and Pyrite into Quartz, Mullite and Hematite: as oxygen concen⁃tration increases from 0 to 5.16%, Quartz content increases from 41.21% to 51.13%, Mullite content increases from 7.24% to 21.42%,and the Hematite content increases from 6.81% to 23.32%. High ash and low calorific value weathered coal can achieve stable combustionin fluidized bed, and when the oxygen concentration of flue gas is between 3%-5%, 2-4 mm weathered coal can maintain high combus⁃tion efficiency and mineral conversion rate, which is conducive to the stable operation of the system and secondary utilization of ash-slag.The result can be used for the fuel-selection of circulating fluidized bed.

0 引言

1 试验

   1.1 试验样品

   1.2 试验装置及方法

2 结果与讨论

   2.1 煤颗粒粒径对风化煤灰渣形成特性的影响

   2.2 燃烧气氛（出口烟气中O2浓度）对风化煤成灰特性的影响

3 结论