移动床活性焦烟气净化工艺中废活性焦的形成与特征分析

Formation and characteristics of used activated coke from flue gas purification process by activated coke in moving bed

移动床活性焦低温干法烟气多污染物脱除技术在钢铁烧结烟气脱硫脱硝工艺中具有良好的适用性,但烟气净化过程中活性焦的损耗成为制约该技术推广应用的关键因素之一。以宝钢烧结烟气脱硫脱硝工艺中所产生的废活性焦为研究对象,通过考察其比表面积、孔容结构、灰分中重金属及碱金属含量、表面官能团特征及脱硫脱硝性能,探究烟气净化过程中活性焦组成、结构及表面性质的变化。结果表明,与新鲜活性焦相比,废活性焦粒度集中分布在0.2~5 mm,其表面的氮、氧、硫元素及过渡金属氧化物含量显著增加,比表面积由191.0 m^2/g增加至499.0 m^2/g,使废活性焦颗粒在150℃下脱硝率由20%提升到70%,120℃下穿透硫容由0.27 mg SO2/g提升至11.08 mg SO2/g,显示了良好的再利用潜力。

The multi-pollutant removal using activated coke(AC)in moving bed under low temperature and dry state showed great prospect in desulfurization and denitrification process of flue gas from steel sintering process.The abrasion of AC in this process was the crucial factors which restricted the wide application of this technology.Being aimed at the used AC which was produced in the process of SOx and NOx removal from Baogang sintering flue gas,the texture properties,including the specific surface area,pore volume structure,the content of heavy metals and alkali metals in ash,surface functional group characteristics and desulfurization and denitration performance of AC were investigated to obtain the formation and variation behavior of used AC.Compared to fresh AC,an obvious increase in the content of N,S and O elements and transition metal oxides were observed in the used AC powder in particle size at 0.2~5 mm,and its specific surface area also increased from 191.0 m^2/g to 499.0 m^2/g.As a result,the NO conversion rate increased greatly from 20%to 70%at 150℃,and the penetrating sulfur capacity was enhanced from 0.27 mg SO2/g to 11.08 mg SO2/g at 120℃.The used AC exhibited a good potentiality for reutilization.