Control of nitrogen oxides emission by selective non-catalytic reduction in preheating section during iron ore pellets production

• 作者: Min Gan Wang Shu Zhi-yun Ji Zhi-an Zhou Xiao-hui Fan Bing Hu Guo-jing Wang Yuan Zhu Ya-fei Sun
• 来源期刊: 钢铁研究学报（英文版）
• 年，卷（期）: 2022,（2）
• 所属期刊栏目: ORIGINAL PAPERS
• 页码范围: 215-222
• 页数: 8页
• 语种: 英文

摘要

Reducing the NOx emission from pelletizing process is of great importance to the green development of iron and steel industry.The flue gas temperature of preheating(PH)section during grate-kiln iron ore pelletizing process typically ranges within 850-1050℃,which meets the temperature requirements of selective non-catalytic reduction(SNCR)for NOx.The in-bed SNCR behavior of NOx in the PH section was investigated,and the influence of relevant parameters was revealed.Results show that with the flue gas temperature rising,the denitration rate reached a peak value and then declined,where the appropriate temperature range was 950-1000℃.Increasing the NH3/NO ratio(NSR)contributed to improving the denitration rate,and the appropriate NSR was 1.0.Oxygen content in the flue gas also showed an important influence on denitration rate,which reached a peak value and then dropped with the oxygen content rising.Under the condition of 18 vol.％oxygen content,the denitration reaction mainly occurred in the form of 4NO+4NH3+O2=4N2+6H2O.For restricting the competitive reaction of NH3 oxidation,the oxygen content in flue gas of PH section should be kept at an appropriate range.In general,the denitration rate reached about 25％in the PH section through spraying ammonia.