摘要
为适应流化床锅炉负荷、温度变化大等复杂工况,研究了氨与煤制合成气构成的混合还原剂的脱硝反应特性。通过机理模拟分析发现,添加合成气后还原剂能显著降低脱硝温度并提高脱硝效率;高氨用量搭配低浓度合成气、低氨用量搭配高浓度合成气将有最佳的脱硝效率;在保证相同脱硝效率时,使用混合还原剂能减少氨用量;为保证脱硝效率和限制氨逃逸量,反应温度需略高于最佳脱硝温度。氧气使得脱硝反应在较低温度下(800~1050℃)进行,并且氧气浓度越高,反应温度窗口越窄,脱硝效率越低;添加合成气能够减小氧浓度变化带来的这些差异。停留时间主要影响较低温度时的反应。停留时间越长,反应温度窗口越宽,脱硝效率越高;加入合成气后可以缩短反应停留时间。合成气与氨气之间可形成较强的协同作用,共同促进脱硝反应的进行,比单独喷氨或单独喷合成气效果更好。
In order to adapt to complex working conditions of fluidized bed boilers such as different load and wide fluctuation in temperature,the characteristics of denitration reaction of mixed reducer,comprised of ammonia and coal-based syngas were studied.Through mechanism analysis,it was found that mixed reducer significantly brings down the temperature window for denitration reactions and promotes denitration efficiency.Using high concentration of ammonia with low concentration of syngas or low concentration of ammonia with high concentration of syngas will result in best denitration efficiency.With NOx emission being equal,injecting mixed reducer lessens the usage of ammonia.To ensure denitration efficiency and control ammonia slip,reaction temperature should be higher than the optimal denitration temperature.Oxygen initiates denitration reactions in comparatively low temperature(800~1050℃).However,increasing the concentration of oxygen results in narrower temperature window and lower denitration efficiency.The existence of syngas diminishes those effects of oxygen.Residence time mainly affects reactions in low temperature.The reaction window is widened and the denitration efficiency increases as residence time elongates.The existence of syngas shortens the residence time necessary for full reaction.There is strong and positive interaction between syngas and ammonia which promotes the denitration reactions,showing a better effect than either injecting ammonia or syngas only.
作者
林晨
于娟
张曜
冯帆
姜金东
朱志祥
毕德贵
张忠孝
LIN Chen;YU Juan;ZHANG Yao;FENG Fan;JIANG Jindong;ZHU Zhixiang;BI Degui;ZHANG Zhongxiao(School of Mechanical Engineering,Shanghai Jiao Tong University,Minhang Distinct,Shanghai 200240,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2020年第1期148-155,共8页
Proceedings of the CSEE
基金
国家重点研发计划项目(2016YFB0600202)~~
关键词
流化床
混合还原剂
脱硝
选择性非催化还原
氨逃逸
fluidized bed
mixed reducer
denitration
selective non-catalytic reduction
ammonia slip
