| 固硫剂对煤燃烧过程中硒挥发性的抑制作用 |
| 摘要点击 1481 全文点击 2278 投稿时间：2000-10-19 |
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| 中文关键词 硒 煤燃烧 污染性抑制 循环流化床 |
| 英文关键词 selenium coal combustion pollution retention circulating fluidized bed combustion |
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| 中文摘要 |
| 为了解煤中硒在燃烧过程中的动态、煤中可交换阳离子含量对煤中硒挥发性的影响,以及固硫剂对煤中硒挥发性的抑制作用,将煤样进行了逐级化学提取实验、燃烧实验、硒抑制实验、X射线衍射分析以及原子荧光光谱分析.实验结果表明,煤在815℃下燃烧,煤中97%以上的硒挥发.在中低温度下煤中可交换阳离子含量影响硒的挥发性.模拟固定床燃烧试验,815℃下CaO对煤中硒挥发性的抑制率范围在¨.6%～50.7%,平均为36.0%.小型循环流化床燃烧试验,加入CaO后硒在不同粒级流化床灰中配置明显发生变化,细粒飞灰中硒含量明显降低,＜0.0308mm飞灰中硒含量从241 mg·kg-1降到10 mg·kg-1.烟道灰中硒含量降到1/4以下,烟道喷淋水中硒含量降低了2个数量级.循环流化床燃烧,CaO对硒挥发性的抑制作用更加明显.固硫剂不仅可以固硫,而且对硒的挥发性也有一定的抑制作用. |
| 英文摘要 |
| For understanding the volatility of selenium, the effect of the contents of exchangeable cations of coal on it, and the retention of selenium using CaO in coal combustion, the sequential chemistry extraction, the fixed bed and circulating fluidized bed (CFB) combustion, X-ray diffraction (XRD) and atomic fluorescence spectrometry (AFS) were undertaken. The results showed that the volatility of selenium was more than 97% in coal combustion at 815℃, and the volatility of selenium was affected by the content of exchangeable cations of coal in low-middle temperature. It was identified that lime can restrain the volatility of selenium. In fixed bed combustion of coal, the retention rates of selenium volatility were between 11.6% and 50.7% using lime. In circulating fluidized bed combustion of coal, partitioning of selenium changed very much in ash of different size fraction between without lime and with lime. Comparing with combustion without lime, the content of selenium in ash from chimney was less than fourth times and that in leaching water from chimney decreased by two orders of magnitude using lime. Retention of selenium volatility using lime is so effective in coal combustion, especially in CFB combustion of coal. |
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