Experimental studies on gas-phase mercury oxidation removal and denitration of coal combustion with NH_4 Br addition  

煤中添加NH_4 Br对气相汞氧化脱除及脱硝的实验研究（英文）

作　　者：赵士林[1,2] 段钰锋[1,2] 周强[1,2] 朱纯[1,2] 佘敏[1,2] 吕剑虹[1,2] 

机构地区：[1]东南大学能源热转换及其过程测控教育部重点实验室,南京210096 [2]东南大学能源与环境学院,南京210096

出　　处：《Journal of Southeast University(English Edition)》2015年第2期226-231,共6页东南大学学报（英文版）

基　　金：The National Natural Science Foundation of China(No.51376046,51076030);the National Key Technology R&D Program of China during the 12th Five-Year Plan Period(No.2012BAA02B01);the United Creative Foundation of Jiangsu Province(No.BY2013073-10);the Fundamental Research Funds for the Central Universities;the Scientific Innovation Research of College Graduates in Jiangsu Province(CXZZ13_0093,KYLX_0115,KYLX_0184)

摘　　要：In order to remove gas-phase mercury and NOx from flue gas, experimental studies on flue gas mercury oxidation removal and denitration of Guizhou anthracite combustion with NH4Br addition were carried out. The influence of NH4Br addition on the ignition temperature and combustion characteristics was studied using a thermogravimetric analyzer. The effects of the NHaBr addition amount on gas-phase mercury oxidation and removal were investigated in a bench scale of 6 kW fluidized bed combustor （FBC）. Mercury concentrations in flue gas were determined by the Ontario hydro method （OHM） and the mercury mass balance was obtained. Results show that the NH4Br addition has little influence on the ignition temperature of Guizhou anthracite. With the mercury mass balance of 95.47%, the proportion of particulate mercury Hg^p, gaseous mercury Hg^0 and Hg^2＋ are 75.28%, 11.60% and 13. 12%, respectively, as raw coal combustion. The high particulate mercury Hg^p in flue gas is caused by the high unburned carbon content in fly ash. When the NH4Br addition amount increases from 0 to 0. 3%, the concentration of gaseous Hg^0 and Hg^2＋ in flue gas decreases continuously, leading to the Hg^p increase accordingly. The oxidation rate of Hg^0 is positively correlated to the Br addition amount. It demonstrates that coal combustion with NH4Br addition can promote Hg^0 oxidation and removal. NOx concentration in flue gas exhibits a descending trend with the NHaBr addition and the removal rate reaches 17.31% with the addition amount of 0.3%. Adding NH4Br to coal also plays a synergistic role in denitration.为脱除烟气中的气相汞和NOx,进行了贵州无烟煤中添加NH4Br对烟气汞氧化脱除协同脱硝的实验研究.在热重分析仪上研究添加NH4Br对着火温度和燃烧特性的影响.在6 k W流化床燃烧(FBC)试验装置上研究了在煤中不同NH4Br添加量对气相汞氧化脱除的影响.采用安大略法(OHM)对烟气中汞形态浓度进行了测定并得出汞质量平衡.结果表明,添加NH4Br对贵州无烟煤的着火温度没有影响.原煤燃烧汞质量平衡率为95.47%,颗粒汞Hgp、气态Hg0和Hg2+比例分别为75.28%,11.60%,13.12%.由于飞灰中含有较高的未燃尽碳,烟气中Hgp浓度较高.随着NH4Br添加量从0增加至0.3%,烟气中气态Hg0和Hg2+减少,Hgp相应增加.Hg0的氧化率与煤中Br的添加量成正相关.这表明煤燃烧中添加NH4Br可促进Hg0的氧化和脱除.烟气中NOx随着NH4Br的添加呈减小趋势,其脱除率在0.3%添加量时达最大(17.31%).添加NH4Br同时具有协同脱硝的作用.

关 键 词：coal additives NH4Br mercury oxidation mercury removal synergistic denitration 

分 类 号：TK16[动力工程及工程热物理—热能工程]