贫氧气氛下固硫剂对煤燃烧特性及S和N释放规律的影响  

Effects of Sulfur-fixing Agent on Coal Combustion Characteristics and S,N Release Law in Condition of Lean Oxygen

作　　者：孟江涛 王菁[1] 杨凤玲[1] 郝艳红[1] 程芳琴[1] MENG Jiangtao;WANG Jing;YANG Fengling;HAO Yanhong;CHENG Fangqin(Shanxi Collaborative Innovation Center of High Value-added Utilization of Coal-related Wastes, Shanxi University, 030006 Taiyuan, China)

机构地区：[1]山西大学国家环境保护煤炭废弃物资源化高效利用技术重点实验室,山西低附加值煤基资源高值利用协同创新中心,太原030006

出　　处：《煤炭转化》2020年第5期27-37,共11页Coal Conversion

基　　金：山西省重点研发计划重点项目(201703D111018);山西省应用基础研究青年基金项目(201801D221345);2018年度襄垣县固废综合利用科技攻关项目(2018XYSDYY-14).

摘　　要：考察了贫氧燃烧过程中,三种钙基固硫剂CaO,CaCO3和Ca(OH)2对燃烧和NOx生成的影响,以及在低氧体积分数燃烧条件下固硫作用的强弱规律。结果表明:针对研究所用煤种,氧体积分数的降低使两个燃烧阶段向一个燃烧阶段过渡;空气及15%氧体积分数时,CaO可促燃,而10%氧体积分数时,三种固硫剂都会抑制燃烧;三种固硫剂按固硫率和催化NOx能力由大到小均依次为CaCO3,Ca(OH)2和CaO,且Ca(OH)2与CaCO3的效果相差不大。燃煤中硫含量及形态与固硫剂分解速率之间的匹配关系决定固硫效果。硫释放速率快时,分解速率较快的固硫剂固硫效果较好;反之,分解较慢的固硫剂效果更好;随氧体积分数的降低,固硫剂煅烧速率几乎不受影响,但固硫剂的固硫作用逐渐减弱,钙对NOx的催化作用逐渐增强。研究认为Ca(OH)2及钙硫比(钙与硫的摩尔质量之比)等于3为较优化的固硫工艺。The effects of three different sulfur-fixing agents based on CaO,CaCO3,and Ca(OH)2 on the combustion characteristics and the release of NOx during the coal combustion process in different oxygen content atmospheres were investigated,and the resulting sulfur fixation capacities by using the three calcium-based sulfur-fixing agents in the lean oxygen combustion conditions were explored.The results show that for the coal used in the present study,the two combustion stages gradually merge into one stage with decreasing oxygen concentration.The CaO-based agent can promote the combustion under the ambient and 15%-oxygen-volume fraction atmosphere,while in the 10%-oxygen-volume fraction atmosphere,all three sulfur-fixing agents show an inhibitory effect on the combustion.The CaCO3-based agent leads to the highest sulfur fixation and NOx catalytic capacities among the three sulfur-fixing agent,and the Ca(OH)2 leads to slightly higher capacities than the CaO-based agent.The sulfur content and morphology in the coal combustion and the decomposition rate of the sulfur-fixing agents together determine the effectiveness of the sulfur-fixing agents.Specifically,when the sulfur release rate is fast,the sulfur fixation agent with a faster decomposition rate is better;otherwise,the sulfur fixation agent with a slower decomposition rate is better.With decreasing oxygen volume fraction,the calcination rate of the sulfur-fixing agent remains almost unchanged;the effectiveness of the sulfur-fixation is slightly weakened;and the catalytic effect of the sulfur-fixing agents on NOx is slightly enhanced.It is considered that the use of Ca(OH)2 with calcium to sulfur ratio corresponding to three as the sulfur-fixing agent is a superior option for the sulfur fixation process.

关 键 词：贫氧气氛 低氮燃烧 钙基固硫 燃烧特性 SO2 NOx 

分 类 号：TQ534[化学工程—煤化学工程]