宁东典型中低阶煤热解过程中氮和硫元素赋存形态与其变迁规律的关联性研究  

Study on correlation between speciation of nitrogen and sulfur elements and their transformation during pyrolysis of typical middle and low-rank coal in Ningdong

作　　者：崔明果 陈慧君[1] 申岩峰 鲍卫仁[1] 常丽萍[1] 王建成[1] CUI Mingguo;CHEN Huijun;SHEN Yanfeng;BAO Weiren;CHANG Liping;WANG Jiancheng(State Key Laboratory of Clean and Efficient Coal Utilization,Taiyuan University of Technology/Key Laboratory of Coal Science and Technology,Ministry of Education,Taiyuan University of Technology/College of Chemistry and Chemical Engineering,Taiyuan University of Technology,030024 Taiyuan,China)

机构地区：[1]太原理工大学煤基能源清洁高效利用国家重点实验室、太原理工大学煤科学与技术教育部重点实验室、太原理工大学化学与化工学院,太原030024

出　　处：《煤炭转化》2025年第1期12-26,共15页Coal Conversion

基　　金：国家自然科学基金重点基金项目(U21A20319)。

摘　　要：作为分级转化比较理想的中低阶煤,认识和理解宁东典型中低阶煤在热转化过程中氮、硫元素迁移转化行为对污染物的调控至关重要。目前,煤热转化工艺多以气化为主,其中热解作为气化的基础阶段,在煤热转化过程中至关重要,因此在深入认识煤质特性的基础上,研究宁东地区典型中低阶煤所含硫、氮元素在热解过程中的迁移与转化规律,不仅有望为宁东中低阶煤的热转化工艺条件优化及污染物控制提供理论参考,也可为目前的气化工艺过程污染物调控提供基础数据。基于此,以宁东地区的羊场湾煤(YCW)、上湾精煤(SW)与梅花井煤(MHJ)为研究对象,使用固定床反应器,探究三种不同硫含量的煤在热解过程中HCN,NH_(3)与H_(2)S的释放规律,主要考察元素的赋存形态、热解温度(300℃~900℃)与升温速率(3℃/min~10℃/min)对氮、硫元素迁移转化的影响。结果表明:HCN的释放量随着温度升高而逐渐增加,NH_(3)的释放主要集中在500℃~900℃,最大释放峰温为700℃,H_(2)S的释放主要集中在400℃~900℃,最大逸出峰温为600℃和800℃(分别对应于硫铁矿硫与部分不稳定有机硫的分解);较高的灰分含量能够阻止自由基间相互结合,使更多的含氢自由基与含氮自由基结合生成HCN,季氮含量越高,NH_(3)的释放量越大,不稳定有机硫占比越高的煤样,H_(2)S的释放越多;适宜的升温速率有利于HCN发生二次反应生成NH_(3),随着升温速率增大,产生热滞后现象,当升温速率由3℃/min提高至10℃/min时,MHJ的HCN,NH_(3)和H_(2)S转化率均呈明显下降趋势,HCN转化率由4.02%降至1.28%,NH_(3)转化率由13.80%降至3.91%,H_(2)S转化率由38.33%降至26.04%。综上,元素赋存形态、热解温度与升温速率对热解过程中氮、硫元素迁移影响均较大。灰分含量、季氮含量与不稳定有机硫含量较低的煤样在10℃/min热解条件下,氮、硫污染物的释放量较低,对环�As a relatively ideal type of middle and low-rank coal for graded conversion,understanding the migration and transformation behavior of nitrogen and sulfur elements during the thermal conversion process of typical middle and low-rank coal in Ningdong is crucial for the control of pollutants.Currently,gasification is the main process for coal thermal conversion,with pyrolysis as the fundamental stage of gasification.Therefore,based on a deep understanding of coal quality characteristics,the migration and transformation patterns of sulfur and nitrogen elements contained in typical middle and low-rank coal from the Ningdong area during the pyrolysis process were investigated.The experimental results are expected not only to provide a theoretical basis for optimizing the thermal conversion process conditions and pollutant control of middle and low-rank coal in Ningdong,but also to offer basic data for pollutant control in gasification processes.Therefore,this paper focuses on Yangchangwan coal(YCW),Shangwan cleaned coal(SW)and Meihuajing coal(MHJ)from Ningdong area as research subjects,using a fixed bed reactor to explore the release rules of HCN,NH_(3) and H_(2)S during the pyrolysis of three different types of coal with varying sulfur contents.The effects of element speciation,pyrolysis temperature(300℃-900℃)and heating rate(3℃/min-10℃/min)on the migration and transformation of nitrogen and sulfur elements are investigated.The experimental results show that the release of HCN gradually increases with temperature.The release of NH_(3) is mainly concentrated between 500℃-900℃,with its maximum release peak at 700℃.The release of H_(2)S is primarily concentrated between 400℃-900℃,with its maximum release peaks at 600℃ and 800℃,corresponding to the decomposition of pyrite sulfur and some unstable organic sulfur,respec‐tively.Higher ash content can prevent the combination of free radicals,allowing more hydrogen-containing free radicals to combine with nitrogen-containing free radicals to form HCN.

关 键 词：煤热解 氮迁移 硫迁移 热解温度 升温速率 元素赋存形态 

分 类 号：TQ530.2[化学工程—煤化学工程]