热解气氛与温度对褐煤半焦“一步法”甲烷化活性的影响

发布时间：2019-03-25 19:04

【摘要】：为提高褐煤热解多联产技术中半焦的利用效率,本文提出将低温热解半焦用于"一步法"制甲烷技术,考察了热解条件对半焦性质和一步甲烷化活性的影响。利用管式炉制备了不同气氛和温度的褐煤热解半焦,采用傅里叶红外光谱、X射线衍射技术和固定床反应器,对半焦表面化学、微晶结构和甲烷化活性进行了表征。结果表明,与N2和H2氛围相比,褐煤在水蒸气氛围中进行热解,半焦表面含氧官能团受到保护而含量更高,同时石墨化程度因受阻而降低,甲烷化活性更高;在水蒸气氛围中,773~873K范围内,随着热解温度升高,褐煤裂解反应进行程度加深,半焦表面含氧官能团数量降低,石墨化程度增加,致使甲烷化活性降低。总之,在水蒸气氛围中,773K时热解形成了一步甲烷化反应活性最好的褐煤半焦,对于低阶褐煤热解过程与气化过程优化联产具有重要指导意义。
[Abstract]:In order to improve the utilization efficiency of semi-coke in the co-production technology of lignite pyrolysis, the low-temperature pyrolysis semi-coke was used to produce methane by one-step process. The effects of pyrolysis conditions on the properties of semi-coke and the activity of one-step methanation were investigated. Pyrolysis semi-coke of lignite at different atmosphere and temperature was prepared by tube furnace. The surface chemistry, microcrystal structure and methanation activity of semi-coke were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and fixed-bed reactor. The results showed that, compared with N2 and H2 atmosphere, lignite pyrolysis in steam atmosphere resulted in higher content of oxygen-containing functional groups on the surface of semicoke, lower graphitization degree and higher methanization activity than those in N2 and H2 atmospheres. In water vapor atmosphere, with the increase of pyrolysis temperature, the degree of lignite pyrolysis deepened, the number of oxygen-containing functional groups on the surface of semi-coke decreased and the graphitization degree increased, resulting in a decrease in methanation activity. In conclusion, a lignite semi-coke with the best methanation activity was formed at 773K in steam atmosphere, which is of great guiding significance for the optimization of co-production of low-order lignite pyrolysis process and gasification process.
【作者单位】：青岛科技大学化工学院清洁化工过程山东省高校重点实验室;
【基金】：国家自然科学基金(21276129,51506105) 山东省自然科学基金重点项目(ZR2015QZ02) 山东省自然科学基金(ZR2015BL028)项目
【分类号】：TD849.2

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