硫改性椰壳活性炭管道喷射脱汞实验研究
Experimental study on mercury adsorption of S-impregnated coconut shell activated carbon by duct injection

选用生物质废弃物椰壳制备活性炭脱汞吸附剂,并在不同温度下进行载硫改性.采用N2吸附/脱附、热重质谱联用(TG-MS)、X射线近边吸收结构(XANES)等方法对吸附剂进行孔隙结构和硫存在形态表征.在模拟烟气管道喷射实验装置上进行汞吸附脱除实验研究.结果表明,载硫温度500 ℃时椰壳活性炭汞吸附效率优于商用富硫活性炭.活性炭汞吸附脱除能力由孔隙结构、硫含量与硫存在形态共同决定.硫含量随着载硫温度的提高而降低,孔隙结构参数得到优化.元素硫、噻吩与硫酸盐为活性炭硫的主要存在形态,噻吩为有机硫的主要形态.元素硫与噻吩均有利于汞吸附脱除,其中元素硫效果最优.模拟烟气组分的加入促进了活性炭脱汞效率的提高.
Coconut shell as a kind of biomass wastes was chosen to prepare the mercury removal activated carbon, which was then modified with elemental sulfur at different temperatures. The pore structure and sulfur forms of adsorbents were characterized by nitrogen(N2)adsorption/desorption, thermogravimetry-mass spectrometry(TG-MS), and X-ray absorption near-edge structure(XANES). Experimental studies on Hg removal were conducted in a duct injection system flowed with simulated fuel gas. The results show that coconut shell activated carbon modified with elemental sulfur at 500 ℃ performs a higher mercury adsorption efficiency than commercial activated carbon with high sulfur content. The mercury removal capacity of activated carbon is controlled by its pore structure, sulfur content, and sulfur forms. With the increase of the impregnation temperature, the total sulfur content decreases while the pore structure parameters are optimized. Elemental sulfur, thiophene, and sulfate are the main forms of sulfur deposited on the carbon surface, and thiophene is the main form of organic sulfur. Elemental sulfur and thiophene benefit the Hg adsorption capacity, and elemental sulfur is more effective. The addition of simulated flue gas components can promote mercury adsorption efficiency of activated carbon