不同空气分级模式下氨煤掺烧数值模拟  

Modeling co-firing ammonia with coal in different air staging modes

作　　者：牛涛 张文振 魏书洲 张超群 李明 初伟 刘平 马仑[4] 王学斌[5] NIU Tao;ZHANG Wenzhen;WEI Shuzhou;ZHANG Chaoqun;LI Ming;CHU Wei;LIU Ping;MA Lun;WANG Xuebin(Yantai Longyuan Power Station Technology Co.,Ltd.,Yantai 264006,China;Sanhe Power Plant Ltd.,Langfang 065201,China;Hebei Innovation Center for Coal-fired Power Station Pollution Control,Langfang 065201,China;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology,Wuhan 430074,China;School of Energy and Power Engineering,Xi′an Jiaotong University,Xi′an 710049,China)

机构地区：[1]烟台龙源电力技术股份有限公司,山东烟台264006 [2]三河发电有限责任公司,河北廊坊065201 [3]河北省燃煤电站污染防治技术创新中心,河北廊坊065201 [4]华中科技大学煤燃烧国家重点实验室,湖北武汉430074 [5]西安交通大学能源与动力工程学院,陕西西安710049

出　　处：《洁净煤技术》2023年第9期145-151,共7页Clean Coal Technology

基　　金：陕西省杰出青年基金资助项目(2021JC-03)。

摘　　要：氨作为零碳燃料和良好的储氢介质,近年来引起广泛关注。未来在燃煤电厂掺烧零碳燃料是碳减排的重要途径。在空气深度分级模式下,对氨煤掺烧进行了数值模拟,讨论了煤燃烧区域不同过量空气系数α工况下炉内的温度场、组分浓度场及NO_(x)排放情况,而各工况总的过量空气系数均维持在1.2。模拟了4个燃烧工况(α=0.696、0.840、0.912、0.996)。对温度场的统计结果表明,随α降低,煤粉燃烧第1阶段的着火位置提前,但形成的高温火焰长度缩短,喷氨口附近的温度更低。在α=0.696工况下,可明显区分出煤粉火焰和氨燃烧火焰。随α提高,二者界限逐渐模糊。α降低有助于在氨燃料喷入上游形成一个较长的还原区,因此氨发生氧化反应的概率降低。但随α降低,炉内燃尽情况降低,CO排放浓度、飞灰含碳量及氨逃逸量提高。炉内NO x浓度统计结果表明,随α降低,NO_(x)排放水平显著降低。进一步对炉内H 2浓度进行统计,发现α=0.696工况下,炉内最高H 2体积分数可达2%,这意味着该工况下氨的分解反应显著增强。由于氨的消耗反应是3个总反应竞争的结果,因此分解反应的增强使氨直接参与氧化的反应减弱。而H 2生成的增加也进一步提高了NO_(x)被还原的几率,使炉内NO_(x)排放水平进一步降低。总之,在实际煤粉炉掺氨运行工况下,可通过空气深度分级的方法,调控氨燃烧区域的温度、氧气浓度,实现低NO_(x)排放。Recently,ammonia has garnered significant attentionaround the world as an effective zero-carbon fuel and hydrogen storage medium.To reduce carbon emissions in coal-fired power plants,the use of zero-carbon fuel blends shows great promise.Investigates the combustion behavior of ammonia coal co-firing under the deep-air staging mode.Specifically,the temperature field,component concentration field,and nitrogen oxide emission in the furnace at varyingαcoefficient conditions are investigated,while maintaining the total excess air coefficient at 1.2.The study analyzes four cases withαcoefficients equal to 0.696,0.840,0.912,and 0.996 respectively.The temperature field reveals that as theαcoefficient decreases,the ignition position of the first stage of pulverized coal combustion advances.However,the length of the high-temperature flame formed is shortened,and the temperature near the ammonia injection port is notably lower.Whenα=0.696,the pulverized coal flame and ammonia combustion flame are distinctly separate,but asαimproves,the boundary between the two gradually becomes blurred.Decreasing theαcoefficient forms a longer reduction zone upstream of ammonia fuel injection,leading to a lower oxygen concentration of ammonia fuel at the moment of injection,hence reducing the probability of ammonia oxidation path.However,as theαdecreases,there is a corresponding decrease in burnout in the furnace,which includes CO emissions concentration,fly ash carbon content,and ammonia escape.However,the influence is very limited in this simulation.Statistical analysis of NO_(x)concentration in the furnace showed that NO_(x)emissions significantly decreased asαdecreased.Furthermore,the highest H 2 concentration in the furnace reached 2%underα=0.696,led to a significant enhancement of ammonia decomposition reaction.Since the consumption reaction of ammonia depends on three global reactions,improved decomposition reaction can reduce the direct participation in oxidation for ammonia.Increased H 2 production also enhances the possib

关 键 词：氨煤掺烧 空气深度分级 过量空气系数 NO_(x) 

分 类 号：TQ53[化学工程—煤化学工程] TK114[动力工程及工程热物理—热能工程]