非沥青基煤质活性焦脱硫脱硝性能研究

Desulfurization and denitrification properties of non-pitch coal-based activated coke

以低成本的非沥青基煤质活性焦（NPAC）为样品,采用固定床反应器以及BET比表面积测试和X射线光电子能谱技术,分析了NPAC的孔结构和表面官能团,考察了NPAC在不同温度下的脱硫脱硝性能,探讨了NPAC的脱硫脱硝机制。结果表明：NPAC表面的孔结构以0.7~1.2nm和1.5~1.6nm微孔为主,含有以类吡啶氮N-6为主的碱性官能团和以内酯、羰基和羧酸衍生物等为主的酸性官能团,碱/酸性官能团浓度分别为0.15 mmol/g和0.05mmol/g;脱硫时,反应温度为60~140℃,SO2在NPAC表面以物理吸附和化学吸附为主,温度升高,穿透时间先增加后减少,80℃时SO2穿透时间最长,为280min;脱硝时,反应温度为30~140℃,NOx在NPAC表面以吸附为主,30℃脱硝反应180min时,NOx的脱除率高达86.35%,温度高于200℃时催化转化起主要作用,260℃时脱硝率为99.44%;在40℃下NPAC可将烟气中少量的SO2完全脱除,同时脱硝率无明显下降。

Low-cost non-pitch coal-based activated coke（NPAC）was taken as sample in this study.The pore structure and surface functional groups of the NPAC were analyzed by BET and XPS techniques,the desulfurization and denitrification performances of the NPAC were investigated in a fixed bed reactor at different temperatures,and the mechanisms of desulfurization and denitrification were discussed.The results demonstrated that,micropores with average pore size ranging from 0.7nm to 1.2nm and 1.5nm to1.6nm dominated on the NPAC surface.The surface of the NPAC contained the basic functional groups and the acidic functional groups,of which the contents were 0.15mmol/g and 0.05mmol/g,respectively.The main basic functional groups were nitrogen-containing species such as pyridine,and the acidic functional groups were major of carboxyls,anhydrides,carbonyls and aromatic alcohols.When the temperature was within the range of 60 ℃to 140 ℃,SO2 was absorbed on the NPAC surface by physisorption and chemisorption.With the increasing desulfurization temperature,the breakthrough time of SO2 increased firstly and then decreased,the breakthrough time of SO2 increased to 280 min at 80℃,which was the longest.The transformation of NOx on the NPAC surface at 30 ℃ to 140 ℃ was mainly conducted by adsorption process.The removal rate of NOxcould be high as 86.35% after denitrification reaction for 180 minutes at30 ℃.When the denitrification temperature was higher than 200 ℃,the catalytic conversion route played main role in the removal of NOx,which caused the NOxremoval rate went up to 99.44% at 260 ℃.In the presence of SO2 with low concentration in the flue gas,the SO2 was removed completely and the denitrification rate has no obvious decrease.