维多利亚褐煤利用过程中氮转化机理研究进展  

Research progress on nitrogen conversion mechanism during utilization of Victorian lignite

作　　者：何海军[1,2] HE Haijun(China Coal Research Institute,Beijing 100013,China;China Coal Technology&Engineering Group Clean Energy Corporation Ltd.,Beijing 100013,China)

机构地区：[1]煤炭科学研究总院,北京100013 [2]中煤科工清洁能源股份有限公司,北京100013

出　　处：《煤质技术》2023年第1期55-64,共10页Coal Quality Technology

基　　金：中煤科工清洁能源股份有限公司基金资助项目(CE-KY-CX-2021-05)。

摘　　要：褐煤是重要的煤炭资源,褐煤利用过程中氮的转化会生成NOx及其前驱体从而导致环境污染,研究褐煤利用过程中氮的转化机理可为解决由煤中氮可能引起的环境问题提供基础技术支撑。结合维多利亚典型褐煤的基础煤质分析,概述其褐煤中氮的含量及存在形式,从热解、燃烧和气化3个方面简述褐煤利用过程中氮的转化机理,并重点从煤中氮向挥发分-N和半焦-N的转化、挥发分-N的热裂解转化、半焦-N的热裂解转化等方面剖析热解过程中氮的转化机理。综合分析褐煤中氮的转化研究可知,煤中氮的主要存在形式为吡咯类氮,其次为吡啶类氮,另外还有少量的季氮和胺类氮;褐煤在较低的热解温度下热解时,氮相对富集在半焦中,N_(2)、焦油-N、HCN和NH_(3)等挥发分-N占煤中总氮的比例低于30%;焦油-N的热解主要含氮产物为HCN,NH_(3)仅占到不足10%的焦油-N;半焦-N热解的主要产物包括HCN、NH_(3)和N_(2);加氢热解时,NH_(3)是主要的含氮气体,主要来自于半焦-N。褐煤在富氧条件下燃烧时,煤中氮主要转化为NO,其次转化为N_(2);褐煤在贫氧条件下燃烧时,煤中氮主要转化为N_(2),其次转化为NO;褐煤与CO_(2)气化时,N_(2)是最主要的含氮气体产物;褐煤与水蒸气气化时,NH_(3)是最主要的含氮气体产物。Lignite is an important coal resource.Nitrogen conversion in the utilization process of lignite will generate NOxand its precursors,resulting in environmental pollution.Research on nitrogen conversion mechanism in the utilization process of lignite can provide basic technical support for solving environmental problems that may be caused by nitrogen in coal.Based on the basic coal quality analysis of Victoria’s typical lignite,the content and existence form of nitrogen in lignite were summarized,and the nitrogen transformation mechanism in the utilization process of lignite was briefly described from three aspects:pyrolysis,combustion and gasification.The nitrogen reaction mechanism of coal pyrolysis process was analyzed mainly from the aspects of the conversion of nitrogen from coal to volatile-N and semi-coke-N,pyrolysis of volatile-N and pyrolysis of semi-coke-N.A comprehensive analysis of nitrogen conversion studies in lignite shows that the main form of nitrogen in coal is pyrrole nitrogen,followed by pyridine nitrogen,and a small amount of quaternary nitrogen and amine nitrogen.During the pyrolysis of lignite at low pyrolysis temperature,nitrogen is relatively enriched in semi-coke,and the proportion of volatile-N,such as N_(2),tar-N,HCN and NH_(3),in the total nitrogen of coal is less than 30%.The main nitrogenous products of tar-N pyrolysis are HCN,and NH_(3)only accounts for less than 10%of tar-N.The main pyrolysis products of semi-coke-N include HCN,NH_(3)and N_(2).During hydropyrolysis,NH_(3)is the main nitrogenous gas,which mainly comes from semi-coke-N.When lignite is burned under oxygen-rich conditions,the nitrogen in the coal is mainly converted to NO,followed by N_(2).When lignite is burned in oxygen-poor condition,nitrogen is mainly converted to N_(2),followed by NO.N_(2)is the main nitrogenous gas product when lignite is gasified with CO_(2).NH_(3)is the main nitrogenous gas product when lignite is gasified with steam.

关 键 词：褐煤 氮 转化机理 热解 燃烧 气化 NOx前驱体 吡咯类氮 

分 类 号：TQ530.2[化学工程—煤化学工程]