典型神华煤/焦官能团分布差异和反应性对比分析Comparative analysis on distribution difference and reactivity of the typical Shenhua coals/cokes functional groups
向柏祥,熊小鹤,卢旭超,黄军,吕钊敏,谭厚章
XIANG Baixiang,XIONG Xiaohe,LU Xuchao,HUANG Jun,LYU Zhaomin,TAN Houzhang
摘要(Abstract):
神华煤储量巨大,因其良好的着火和燃尽特性,已成为我国主要的动力用煤之一,年消耗量超过我国煤炭总消耗量的1/10。神华煤种类较多,按灰熔点可分为高灰熔点的系列如石炭煤和准格尔煤,低灰熔点的系列如神混煤,低灰熔点煤产量大,一般是电厂的主烧煤种,为防止结渣,电厂多以低熔点煤和高熔点煤按7∶3或8∶2比例进行掺配混烧。目前的研究关注神华煤的工程燃用较多,而针对不同种类神华煤的微观差异性关注较少,选取神混、石炭2种典型的神华煤,采用红外光谱技术对其原煤和煤焦的官能团分布进行了表征比较,研究发现,神混、石炭2种烟煤的官能团分布相似,均存在CC和C C、—CH_3、—CH_2等烷烃基团以及含N、含S基团;从红外吸收峰强度看,石炭煤官能团要高于神混煤。受热成焦后,神混焦的—CH_3、—CH_2以及芳香碳碳双键等官能团吸收峰强度明显高于石炭焦。神混、石炭原煤脂肪链长接近,但石炭焦脂肪链长显著增加,而神混焦脂肪链长变化并不明显。通过扫描电镜观察到神混煤存在明显的相互交替的条带状煤岩结构,高温成焦后碳的晶体结构变得有序,孔隙结构明显增加。通过热重反应器对神混、石炭2种煤焦的氧化活性进行了比较,发现神混焦的反应活性明显高于石炭焦,神混焦更易燃尽。因此,从燃烧特性比较看,选用神混作为主力燃用煤种是合适的。
Because of enormous reserves,good ignition and burnout characteristics,Shenhua coal has become a kind of important power coal used in China.The annual consumption is more thanten percent of the gross coal consumption. There are many kinds of Shenhua coal,which can be divided into high ash fusion point( e.g.,Carboniferous,Junggar coal) and low ash fusion point( e.g.,Shenhun) in terms of ash fusion temperature.The output of low ash melting point coal is large,which is generally the main coal for power plant.However,in order to prevent slagging,the high and low ash fusion coal are blended in appropriate proportions( e.g.,7 ∶ 3,8 ∶ 2).To date,the researches mainly focused on the engineering application of Shnehua coal,whereas the investigation on the microstructure difference of different Shenhua coal has rarely been reported. Thus,two typical Shenhua coals,such as Shenhun coal and Carboniferous coal,were selected to characterize and compare the functional group distribution of raw coal and coal char by infrared spectroscopy in this work.The results show that the distribution of the functional group in Shenhun coal is similar to that in Carboniferous coal.Both Shenhun and Carboniferous coal find the alkane group,including carbon-carbon double bond,carbon-carbon triple bond,methyl and methylene group,the nitrogen-containing and sufur-containing groups. In term of FTIR absorption strength,the functional groups of Carboniferous coal is higher than that of Shenhun coal.However,FTIR absorption strength measurements show that the carbon-carbon double bond,methyl and methylene group in Shenhun char is higher than that in Carboniferous char.This is probably because the fatty chain in Shenhun and Carboniferous coal are almost of the same length.The length of fatty chain of Carboniferous char increases significantly,meanwhile,that of Shenhun char shows little change.In addition,It is observed by SEM thatthere is obviously alternative banded rock-coal structure in Shenhun coal. However,the crystalline structure becomes in order,and the pore structure increases significantly after coking.The oxidation activity of Shenhun coke and Carboniferous char was compared by thermogravimetric reactor.Additionally,it is found that the reactivity of Shenhun char is obviously higher than that of Carboniferous char,and Shenhun coke is more flammable.Therefore,from the comparison of combustion characteristics,it is appropriate to choose Shenhun as the main fuel coal.
关键词(KeyWords):
官能团分布;反应活性;红外光谱;热重
functional groups distribution;reactivity;FTIR;thermogravimetry
基金项目(Foundation): 国家重点研发计划资助项目(2018YFB0604203)
作者(Author):
向柏祥,熊小鹤,卢旭超,黄军,吕钊敏,谭厚章
XIANG Baixiang,XIONG Xiaohe,LU Xuchao,HUANG Jun,LYU Zhaomin,TAN Houzhang
DOI: 10.13226/j.issn.1006-6772.20020601
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