内蒙煤UCG煤焦的物化特性及其对焦化废水的净化

Physicochemical Properties of UCG Residual Cokes From Neimeng Lignite and Its Purification of Coking Wastewater

借助煤炭地下气化模拟实验系统,采用富氧空气/水蒸气两阶段气化方法完成内蒙煤的地下气化实验,获取残留煤焦。采用SEM、FTIR、低温氮气物理吸附仪对煤焦的表面形貌、官能团和孔结构特性进行表征,通过淋滤实验研究煤焦对焦化废水的吸附,进而考察煤焦的吸附性能。结果表明,气化后残焦表面较为粗糙,有明显的孔隙裂隙,且保留部分含氧官能团;气化残焦的比表面积和孔容积分别达到133.87 m^2/g和0.118 cm^3/g,远大于原煤的20.19 m^2/g和0.045 cm^3/g;气化残留煤、焦对焦化废水均具有一定的净化作用,内蒙煤对TOC的脱除率随淋滤时间延长逐渐增大至62.8%,氨氮脱除率则逐渐减小至23.45%;残焦对废水中氨氮的脱除率也随时间延长而减小,但对有机污染物具有更高的吸附性能,TOC脱除率保持在70%以上。

Model test of underground coal gasification（UCG） of Neimeng lignite has been carried out by UCG model test system,and the residual cokes were obtained after gasification.SEM,FTIR and N_2 adsorption at 77 K were applied to characterize the surface morphology,functional groups and pore structure parameters of coal and coal char samples,and its adsorption performances were also investigated by researching the purification of coking wastewater through column leaching experiments.The coarse surface and obvious hole and cracks of residual cokes were observed,partial oxygen-containing functionalities were also preserved,and the specific surface area and total pore volume of coke samples increased to 133.87 m^2/g and 0.118 cm^3/g,much higher than that of20.19 m^2/g and 0.045 cm^3/g of raw coal sample.It was also found that coking wastewater could be purified by residual coal and coke samples,removal rate of TOC by coal sample increased to 62.8%with time under experimental conditions,but ammonium decreased to 23.45%.Compared with raw coal,higher removal rate of organic contaminants were observed by cokes,removal rate of ammonium also decreased with leaching time,removal rate of TOC could remain above 70%.