脱硝系统采用烟道尿素直喷热解工艺的可行性研究  

Feasibility study on urea direct injection pyrolysis in flue duct of denitration system

作　　者：董陈[1] 黄昌跃 李明皓[1,3] 王晓冰 潘栋[1,3] 李淑宏 徐晓涛[1,3] 袁壮 DONG Chen;HUANG Changyue;LI Minghao;WANG Xiaobing;PAN Dong;LI Shuhong;XU Xiaotao;YUAN Zhuang(Xi’an Thermal Power Research Institute Co.,Ltd.,Xi’an 710054,China;Huaneng Hainan Power Generation Co.,Ltd.,Haikou 570125,China;Shaanxi Engineering Research Center of Coal Fired Boiler Environmental Protection,Xi’an 710054,China)

机构地区：[1]西安热工研究院有限公司,陕西西安710054 [2]华能海南发电股份有限公司,海南海口570125 [3]陕西省燃煤电站锅炉环保工程技术研究中心,陕西西安710054

出　　处：《热力发电》2022年第2期157-163,共7页Thermal Power Generation

基　　金：中国华能集团有限公司科技项目(HNKJ21-H46)。

摘　　要：以某125 MW燃煤机组为例,使用数值模拟方法对选择性催化还原(SCR)脱硝反应器进口烟道烟气条件下尿素直喷热解技术应用的可行性进行了研究。研究结果表明:在燃煤机组SCR反应器进口烟道烟气条件下,尿素热解的主要产物为氨气和异氰酸,在300~400℃烟气温度范围内,当停留时间达到0.5 s以上时,尿素的热解效率在95%以上;在SCR脱硝系统进口烟道布置12支喷枪,尿素溶液平均雾化粒径为35μm,在尿素溶液喷射点下游设置混合器能够使第一层催化剂入口截面上NH_(3)的摩尔分数分布均匀性最好,均方根偏差为4.8%;在尿素直喷热解工程应用时,宜选用带有保温隔热结构和冷却风装置的双流体喷枪,并将喷枪进行分区设置。Numerical simulations are carried out on a 125 MW coal-fired power unit to study the feasibility of application of urea direct injection pyrolysis technology in flue duct at inlet of the selective catalytic reduction(SCR)denitration system.The results show that,under the SCR inlet flue gas condition,the products of urea pyrolysis are NH_(3) and HNCO.When the temperature varies from 300℃to 400℃,the urea pyrolysis efficiency can reach over 95%when the residence time of urea is longer than 0.5 s.By setting up 12 injectors at inlet flue duct of the SCR denitration system,the average atomization particle size of urea solution can reach 35μm.Using proper mixer at downstream of the urea solution injectors can achieve an optimum uniform distribution of NH_(3) mole fraction on inlet plane of the first catalyst layer,with a root mean square deviation of 4.8%.For engineering application of the urea direct injection pyrolysis technology,dual-fluid injectors used in the SCR denitration system should have thermal insulation structure and cooling air device,and the injectors should be divided into several zones to achieve optimum NH_(3) distribution.

关 键 词：尿素制氨 直喷 燃煤机组 喷枪 雾化粒径 

分 类 号：X511[环境科学与工程—环境工程]