炭材料的配煤制备及低温脱硝性能

Low temperature flue gas denitrification performance of carbon materials prepared by blending coal method

为了研究配煤对脱硝用炭材料孔结构及表面化学性质的影响,利用烟煤和无烟煤配煤制备炭材料,通过密度函数理论解析N_2在77 K条件下对炭材料样品的吸附/解吸等温线,得出其孔容参数和BET比表面积,并通过酸碱滴定及XPS表征炭材料的表面化学性质。利用固定床反应装置在150℃、NO体积分数为1 000×10^(-6)条件下模拟烟气脱硝过程。结果表明:通过配煤制备的炭材料孔结构的发育兼具了2种煤的特点,而其表面化学性质比单种煤制备的炭材料更为丰富。炭材料表面酸性位含量与其脱硝性能具有较好的相关性,相关系数R^2=0.969;烟气中O_2的存在可以促进NO转化率的提高。而H_2O的极性高于NH_3,在亲水性酸性含氧官能团的吸附中占据优势,因此随着烟气中含水量的增加可显著降低炭材料的脱硝效率。

In order to study the coal blending affected to the pore structure and surface chemistry properties of carbon material for denitrification from flue gas,carbon material samples were prepared by blending coal from bituminous and anthracite. Pore structures of samples were calculated N2 adsorption/desorption at 77 K by density functional theory.Surface chemistry of theses carbons had been characterized by X-ray photoelectron spectroscopy（ XPS） and acid-base titration.Denitrification experiments from simulated flue gas of 1 000×10-6 NO concentration by carbon material samples were conducted on a fixed bed reactor at temperature 150 ℃.The results show that pore structure development of carbon material prepared by blending bituminous and anthracite both have two raw material coal feature,whereas its surface chemical more rich than carbon material prepared from single coal.An ideal correlation between SCR catalytic activity and acidic sites content is observed and correlation coefficient R2 reaches 0. 969.The NO conversion seems to be promoted by presence of oxygen in flue gas.Increasing the gas-phase H2 O concentration decreases catalytic activity of carbon material. It can be concluded that the H2O molecules compete with NH3 for the same hydrophilic acid oxygen containing functional groups because molecular of H2O has more polarity than NH3.