Study of Oxy-fuel Coal Combustion in a 0.1 MWth Circulating Fluidized Bed at High Oxygen Concentrations
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- 作者：Wei Li ; Shiyuan Li ; Qiangqiang Ren ; Li Tan ; Haoyu Li ; Jingzhang Liu ; Qinggang Lu
- 刊名：Energy & Fuels
- 出版年：2014
- 出版时间：February 20, 2014
- 年：2014
- 卷：28
- 期：2
- 页码：1249-1254
- 全文大小：309K
- ISSN：1520-5029
文摘
The combustion and emission characteristics under three kinds of firing modes [O2/N2, O2/CO2, and O2/recycled flue gas (RFG)] at high oxygen concentrations were investigated in a 0.1 MWth circulating fluidized-bed combustion system. The 0.1 MWth circulating fluidized-bed combustion unit was built in 2010 and retrofitted to use RFG in 2012, which was specially designed for combustion at high oxygen concentrations (up to 55%). The experimental results showed that CO2 concentrations in the flue gas reached a maximum of 93% when the overall oxygen concentration was in the range of 46.4鈥?4.6% during the combustion. Under the O2/RFG firing mode, the CO concentration dropped from 803.4 to below 100 mg/MJ with the increase of the concentration of oxygen in the flue gas from 1.1 to 7.5%. The fuel N to NO conversion was in the range of 3.5鈥?.6% under the O2/RFG firing mode, which was much less than that observed under the O2/N2 mode (8.1鈥?.4%) and O2/CO2 mode (6.5鈥?.6%). The limestone utilization in the O2/RFG firing mode was found to be much lower than that for both O2/N2 and O2/CO2 modes. Sulfur capture efficiencies were 70.2 and 93.7% under O2/RFG and O2/N2 firing mode conditions, respectively, with a Ca/S molar ratio of 2.2. An increase in the Ca/S molar ratio to 3 resulted in sulfur capture efficiencies of 83.9% under the O2/RFG firing mode.