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活化半焦对胜利褐煤热解挥发分氮的催化重整

Study on catalytic reforming of volatile-N from pyrolysis of Shengli brown coal by activated chars

  • 摘要: 为减少褐煤热解过程中有害氮产物(包括HCN、NH3和焦油-N)的释放,以生物质、褐煤、烟煤和无烟煤为原料制备的半焦以及负载质量分数7%、10%、13%和15%Ca2+的烟煤半焦作为催化剂,在两段流化床石英反应器中进行胜利褐煤热解挥发分氮的催化重整研究。结果表明:半焦有助于促进焦油和HCN的二次反应,降低焦油-N和HCN的产率,增加N2的产率。半焦中Ca2+的加入,有利于释放半焦催化剂中的H自由基,从而进一步催化焦油-N的裂解。半焦催化剂中烟煤半焦的催化效果最好,较佳的Ca2+负载量为13%。影响半焦催化重整活性的主要因素有半焦比表面积、表面含氧官能团、碱金属和氢自由基。

     

    Abstract: In order to decrease the release of harmful nitrogen (including HCN, NH3 and tar-N) during the pyrolysis of brown coal, taking chars that prepared with bi omass, brown coal, bituminous coal and anthracite and chars with loading mass fraction 7%,10%, 13% and15% Ca2+ as catalysts, the catalytic reforming of volatile-N fr om pyrolysis of Shengli brown coal was studied in a two-stage fluidized-bed quartz reactor. The results showed that activated char apparently contributed to the second ary reaction of tar and HCN, thus reducing the production rate of tar-N and HCN as well as increasing the yield of N2.Ca2+loaded in char was beneficial to release hydr ogen radicals and further catalyze tar-N cracking. Overall, the char catalyst derived from bituminous coal had the better catalytic activity than the chars from other mate rials, whereas the loading level of Ca2+on char should be controlled at around 13% to achieve the best performance in this study.The major factors that affected char ac tivity were the specific surface area, the O-containing functional groups, alkali metals and hydrogen radicals.

     

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