石灰石抑制石油焦和煤混烧过程NO排放机理的研究  

Study on mechanism of limestone inhibiting NO emission during co-combustion of petroleum coke and coal

作　　者：闫碧晨 骆仲泱 王霄焕 解桂林[1] 管文洁 YAN Bi-chen;LUO Zhong-yang;WANG Xiao-huan;XIE Gui-lin;GUAN Wen-jie(State Key Laboratory of Clean Energy Utilization,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]浙江大学能源清洁利用国家重点实验室,浙江杭州310027

出　　处：《能源工程》2022年第6期32-41,共10页Energy Engineering

基　　金：国家重点研发专项(2019YFE0100100-05);中央高校基本科研业务费专项资金资助(226-2022-00041)。

摘　　要：循环流化床(CFB)锅炉进行石油焦和煤混烧,是高效、清洁利用高硫石油焦的有效途径。混烧过程中,为满足SO_(2)排放要求,通常采用炉内添加石灰石的脱硫工艺,而该工艺会引起炉内氮氧化物浓度的变化。基于工业CFB锅炉投停石灰石NO_(x)“突降缓升”的实验现象,在实验室规模的20 kW CFB锅炉和立式管式炉中,结合机理实验、物相分析和Factsage计算的方法,明确了石灰石抑制NO排放的机理。结果表明:CFB内强烈的氧化还原交变气氛下,固硫中间产物CaS是抑制NO排放的关键物质;CaS不仅能够促进CO还原NO,而且自身参与了分解NO的化学反应而被消耗,且反应在低温下更容易进行。研究结论可为深挖CFB低氮燃烧潜力,实现炉内NO和SO_(2)的一体化脱除提供有价值的指导方案。The co-combustion of petroleum coke and coal in a circulating fluidized bed(CFB)boiler is an effective way to efficiently and cleanly utilize high-sulfur petroleum coke.In order to reduce the SO_(2)emissions in co-firing,the desulfurization process of adding limestone in the furnace is usually used,however,of the concentration of nitrogen oxide in furnace is risen.In respect to the sudden fall and slow rise of concentration of NO_(x)in the process of adding and stopping limestone in industrial CFB boiler,the mechanism of limestone inhibiting NO emission was clarified in a laboratory-scale 20kW CFB boiler and vertical tube furnace,combined with the methods of mechanism experiment,phase analysis and Factsage calculation.The results show that under the strong redox alternating atmosphere of CFB,the intermediate product of sulfur fixation,CaS,the key substance to inhibit NO emission,can not only promote the reduction of NO by CO,but also participate in the chemical reaction of decomposing NO and be consumed;the reaction is easier to carry out at low temperature.The research mechanism of this paper provides a guiding scheme for the integrated removal of NO and SO_(2)in CFB.

关 键 词：石油焦 混烧 石灰石 NO CAS 

分 类 号：X511[环境科学与工程—环境工程]