Combustion behaviour of ultra clean coal obtained by chemical demineralisation
Combustion behaviour of ultra clean coal obtained by chemical demineralisation
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DOI：
10.1016/s0016-2361(03)00181-9
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发表时间：
2003-10
期刊：
影响因子：
7.4
通讯作者：
F. Rubiera;A. Arenillas;B. Arias;J. J. Pis-J.;I. Suárez‐Ruiz;K. Steel;J. Patrick
中科院分区：
文献类型：
--
作者：
F. Rubiera;A. Arenillas;B. Arias;J. J. Pis-J.;I. Suárez‐Ruiz;K. Steel;J. Patrick
由于化石燃料的使用和随之而来的对提高燃烧效率的需求而引起的日益增加的环境问题导致了新的煤清洁和利用方法的开发。然而，如果煤的燃烧特性差，那么通过物理或化学方法从煤中除去大多数矿物质所获得的好处就可能被取消。本工作对灰分含量为6%的高挥发分烟煤进行了氢氟酸和硝酸浸出的化学脱矿，使精煤的灰分含量降至0.3%。用光学显微镜和扫描电子显微镜分析了原始煤和处理煤在沉降炉中的挥发分，并对所得半焦的结构和形貌进行了分析。采用热重法研究了不同温度下煤焦在空气中的等温燃烧反应特性。在1000 °C的落管式炉中对两种煤的燃烧行为和污染物排放进行了比较。研究结果表明，经化学处理后的煤的结构、形貌和反应性与未经化学处理的煤的结构、形貌和反应性有很大的不同。由化学处理引起的变化增加了在落管式炉中确定的燃烧效率，事实上对于脱矿物质煤获得了更高的燃尽水平。
The increasing environmental concern caused by the use of fossil fuels and the concomitant need for improved combustion efficiency is leading to the development of new coal cleaning and utilisation processes. However, the benefits achieved by the removal of most mineral matter from coal either by physical or chemical methods can be annulled if poor coal combustibility characteristics are attained. In this work a high volatile bituminous coal with 6% ash content was subjected to chemical demineralisation via hydrofluoric and nitric acid leaching, the ash content of the clean coal was reduced to 0.3%. The original and treated coals were devolatilised in a drop tube furnace and the structure and morphology of the resultant chars was analysed by optical and scanning electron microscopies. The reactivity characteristics of the chars were studied by isothermal combustion tests in air at different temperatures in a thermogravimetric system. Comparison of the combustion behaviour and pollutant emissions of both coals was conducted in a drop tube furnace operating at 1000 °C. The results of this work indicate that the char obtained from the chemically treated coal presents very different structure, morphology and reactivity behaviour than the char from the original coal. The changes induced by the chemical treatment increased the combustion efficiency determined in the drop tube furnace, in fact higher burnout levels were obtained for the demineralised coal.