摘要
为了考察H_(2)O_(2)-咪唑类离子液体体系脱除煤中硫分和灰分的效果,选取具有相同阳离子的5种亲水性离子液体和2种疏水性离子液体(ILs),即:[BMIM][Br],[BMIM][Cl],[BMIM][BF_(4)],[BMIM][HSO_(4)],[BMIM][H_(2)PO_(4)],[BMIM][PF_(6)]和[BMIM][NTf_(2)],分别与30%H_(2)O_(2)共同作用于宁东SM煤,对反应后的离子液体进行回收再利用。用化学法测定反应前后煤样的形态硫,并用傅里叶变换红外光谱仪(FT-IR)、X-射线衍射仪(XRD)、比表面及孔隙度分析仪(BET)及热重分析仪(TG)等对反应前后煤样进行表征。结果表明:离子液体的加入,改善了H_(2)O_(2)的脱硫脱灰能力,其中H_(2)O_(2)-[BMIM][PF_(6)]体系处理后煤样的脱硫率比单纯H_(2)O_(2)处理增大了18.76%,H_(2)O_(2)-[BMIM][NTf_(2)]体系处理后煤样的脱灰率比单纯H_(2)O_(2)处理增大了27.50%。疏水性离子液体比亲水性离子液体对H_(2)O_(2)脱硫脱灰的改善作用更为明显。FT-IR表征结果表明,经H_(2)O_(2)-ILs体系作用后煤样中的含硫官能团的特征峰强度相对于H_(2)O_(2)单独作用的煤样明显降低,说明离子液体作用可使煤中的硫分被有效脱除。XRD表征结果表明,经H_(2)O_(2)-ILs体系处理后煤样中石英等各种矿物质的衍射峰强度相对于H_(2)O_(2)单独作用的煤样明显降低,说明离子液体作用煤中的灰分被部分脱除。BET表征结果表明,H_(2)O_(2)-ILs体系处理后煤样相比于H_(2)O_(2)单独处理煤样,其比表面积和平均孔径都有所增大,说明离子液体的加入使煤的结构更加松散。TG表征结果表明,H_(2)O_(2)-ILs体系处理样在热解过程中比原煤有更多的挥发性物质逸出,发热量小幅度降低。离子液体经过7次循环利用,随着循环次数的增加,脱硫脱灰效果稍有下降。
In order to investigate the effect of H_(2)O_(2)-imidazoles ionic liquids systems on the desulfurization and demineralization of coal,five hydrophilic and two hydrophobic ionic liquids with same cation,i.e.[BMIM][Br],[BMIM][Cl],[BMIM][BF_(4)],[BMIM][HSO_(4)],[BMIM][H_(2)PO_(4)],[BMIM][PF_(6)]and[BMIM][NTf_(2)],were selected and respectively combined with 30%H_(2)O_(2)to remove sulfurs and minerals from Ningdong SM coal,after which the ionic liquids were recycled and reused.The sulfur species of the coal samples before and after the treatment were determined by a wet-chemical method,and characterized by FT-IR,XRD,BET and TG analyses.The results showed that the use of ionic liquids could greatly improve the efficiency of H_(2)O_(2)towards the desulfurization and demineralization of coal.Specifically,in comparison with the H_(2)O_(2)system,the H_(2)O_(2)-[BMIM][PF_(6)]system showed an enhanced desulfurization rate by 18.76%,while the H_(2)O_(2)-[BMIM][NTf_(2)]system exhibited an improved deminera-lization rate by 27.50%.Overall,the hydrophobic ionic liquids had superior desulfurization and demineralization performances to their hydrophilic counterparts.FT-IR characterization results showed that the characteristic peak strength of sulfur-containing functional groups in the coal sample after treated with H_(2)O_(2)-ILs system was significantly lower than that of the coal sample treated with H_(2)O_(2)alone,indicating that the content of sulfur in the coal was decreased in the presence of ionic liquids.The XRD results showed that the diffraction peak intensities of quartz and other minerals in the coal sample after treatment with H_(2)O_(2)-ILs system were significantly lower than that of the coal sample with treatment of H_(2)O_(2)alone,indicating that the removal efficiency of ash in the coal was enhanced due to the presence of the ionic liquids.BET results showed that the specific surface area and average pore diameter of the samples treated with H_(2)O_(2)-ILs system were increased as compared to that of the samples treated with H_(2)O_(2)alone,indicating that the structure of the coal would become loose.TG results showed that the samples processed by H_(2)O_(2)-ILs system had more volatile substances escaping during the pyrolysis than raw coal,and the calorific value was slightly reduced.More importantly,the ionic liquids only showed slightly decreased desulfurization and demineralization efficiency during the regeneration of 7 cycles,showing the good stability of ionic liquids.
作者
李梅
孙功成
程雪云
金权
李佳佳
徐荣声
LI Mei;SUN Gongcheng;CHENG Xueyun;JIN Quan;LI Jiajia;XU Rongsheng(School of Chemistry and Chemical Engineering,North Minzu University,Yinchuan 750021,China;Ningxia Key Laboratory of Solar Chemical Conversion Technology,North Minzu University,Yinchuan 750021,China;Key Laboratory for Chemical Engineering and Technology,State Ethnic Affairs Commission,North Minzu University,Yinchuan 750021,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2020年第S01期490-498,共9页
Journal of China Coal Society
基金
国家自然科学基金资助项目(20666001)
关键词
离子液体
脱硫
脱灰
形态硫
离子液体再生
ionic liquids
desulfurization
demineralization
sulfur forms
ionic liquid regeneration
