Sulfur evolution in chemical looping combustion of coal with MnFe2O4 oxygen carrier.
Sulfur evolution in chemical looping combustion of coal with MnFe2O4 oxygen carrier.
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DOI：
10.1016/s1001-0742(13)60546-x
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发表时间：
2014-05
影响因子：
6.9
通讯作者：
Baowen Wang;Chuchang Gao;Wei-shu Wang;Haibo Zhao;C. Zheng
中科院分区：
文献类型：
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作者：
Baowen Wang;Chuchang Gao;Wei-shu Wang;Haibo Zhao;C. Zheng
煤的化学环燃烧（CLC）作为一种新型燃烧技术，因其在二氧化碳捕获方面的优势而受到越来越多的关注。煤中硫的析出无论从操作角度还是从环境角度来看，都造成了巨大的危害。本研究合成了一种mnfe2o4复合氧载体（OC），并利用热重分析仪(TGA)-傅里叶变换红外光谱仪（FT-IR）对其与中国典型高硫煤——柳枝烟煤进行了反应。采用实验与热力学模拟相结合的方法，系统研究了LZ煤与MnFe2O4OC反应过程中硫化物的演化规律。对MnFe2O4与LZ反应的TGA-FTIR分析表明，与单一参考氧化物mn3o4或Fe2O3相比，MnFe2O4表现出较好的反应活性，so2的生成主要与MnFe2O4氧化H2S有关。LZ煤与MnFe2O4反应的实验分析，包括x射线衍射和x射线光电子能谱分析，验证了MnFe2O4的主要还原对应物是fe3o4和MnO，与热力学模拟结果吻合较好。所得的MnO有利于稳定还原后的mnfe2o4，避免严重的烧结，但MnO中的氧没有得到充分利用。同时，LZ煤中存在的大部分硫在与MnFe2O4的LZ反应中转化为固体MnS，并进一步氧化为MnSO4。最后，要解决mnns和mn2sio4、mnsio3等锰硅酸盐的形成问题，以保证还原后的MnFe2O4完全再生。
Chemical looping combustion (CLC) of coal has gained increasing attention as a novel combustion technology for its advantages in CO2capture. Sulfur evolution from coal causes great harm from either the CLC operational or environmental perspective. In this research, a combined MnFe2O4oxygen carrier (OC) was synthesized and its reaction with a typical Chinese high sulfur coal, Liuzhi (LZ) bituminous coal, was performed in a thermogravimetric analyzer (TGA)-Fourier transform infrared (FT-IR) spectrometer. Evolution of sulfur species during reaction of LZ coal with MnFe2O4OC was systematically investigated through experimental means combined with thermodynamic simulation. TGA-FTIR analysis of the LZ reaction with MnFe2O4indicated MnFe2O4exhibited the desired superior reactivity compared to the single reference oxides Mn3O4or Fe2O3, and SO2produced was mainly related to oxidization of H2S by MnFe2O4. Experimental analysis of the LZ coal reaction with MnFe2O4, including X-ray diffraction and X-ray photoelectron spectroscopy analysis, verified that the main reduced counterparts of MnFe2O4were Fe3O4and MnO, in good agreement with the related thermodynamic simulation. The obtained MnO was beneficial to stabilize the reduced MnFe2O4and avoid serious sintering, although the oxygen in MnO was not fully utilized. Meanwhile, most sulfur present in LZ coal was converted to solid MnS during LZ reaction with MnFe2O4, which was further oxidized to MnSO4. Finally, the formation of both MnS and such manganese silicates as Mn2SiO4and MnSiO3should be addressed to ensure the full regeneration of the reduced MnFe2O4.