通过自制的煤炭地下气化模拟系统,采用富氧空气/水蒸气两阶段气化工艺,完成内蒙褐煤的地下气化模拟实验。利用傅里叶红外光谱、低温氮气物理吸附仪和扫描电镜对气化残留半焦的表面官能团、孔结构及表面形貌进行表征,进而考察了半焦对苯酚模拟废水中苯酚及煤气洗涤水中总有机碳(TOC)的脱除效果。实验结果表明:半焦孔径主要分布在1-4nm之间,表面有较丰富的含氧官能团及较多的孔洞和裂隙,其孔结构、含氧官能团及孔洞裂隙均有利于污染物在半焦内的迁移和吸附;气化半焦对苯酚的吸附符合Langmuir等温吸附模型,为单分子层吸附;实验条件下最大吸附率为97.95%,吸附量为2.44mg/g;气化半焦对煤气洗涤水中TOC的脱除随吸附时间的变化具有阶段性,脱除率可达88.1%。
Through self-designed underground coal gasification(UCG)model test system,the UCG test of Inner Mongolian lignite was carried out by applying oxygen-enriched air/steam two-stage gasification method. The functional groups,porous characteristics and surface morphology of the semi-coke were characterized by applying Fourier transform infrared spectroscopy(FTIR),automatic specific surface and porosity analyzer and scanning electron microscope(SEM). The uptake of phenol in simulated wastewater and TOC in gas washing water by UCG semi-coke were further investigated. Oxygen enriched functional groups,cracks and pores in range of 1—4 nm were found in semi-coke samples,which may be favorable for the migration and adsorption of pollutants. The results showed that adsorption data of phenol by UCG semi-coke can be well fitted by Langmuir adsorption isotherm. The maximum removal rate of phenol and adsorption capacity could be 97.95% and 2.44mg/g,respectively. The removal rate of TOC in gas washing water varied with the increase of time,and the maximum of 88.1% can be reached.