NOX emissions are 78.6%-83.5% lower than the 2019 new national standard

——The Birth of Yuxing Hot-blast Stove Low Nitrogen Combustion Technology

Our reporter Xia Jiesheng

Timely rain that helps iron-smelting enterprises to save energy, reduce costs and increase efficiency

　　Nitrogen oxides, sulfur dioxide, and dust particles emitted by the chimneys of the iron and steel industry, a major industrial polluter, are the main culprits of air pollution. Among them, sulfur dioxide is caused by burning coal, dust particles are caused by dust removal, and the formation of nitrogen oxides is inseparable from the mixed combustion temperature and combustion mechanism. In 2019, the five ministries and commissions of the Ministry of Ecology and Environment, the National Development and Reform Commission, the Ministry of Finance, the Ministry of Industry and Information Technology, and the Ministry of Transport jointly issued Document No. 35, Huanqiqiang (2019), to formulate ultra-low emissions for iron-making hot blast stoves The standard will be implemented in April 2019. The new standard requires that the indicators of nitrogen oxides, sulfur dioxide, and dust particles in exhaust smoke be lower than 200mg/m³, 50mg/m³, and 10mg/m³. Compared with the unorganized emission period before 2019, the natural nitrogen oxide 100-500mg/m³ emission management has provided a basis for the implementation of governance. In order to meet the standards, steel companies have spent huge sums of money to establish professional desulfurization, denitrification and dust removal institutions and equipment, which greatly increased the production and operation costs of the enterprises, greatly increased the burden on the enterprises, and damaged their interests. And Henan Yuxing Hot Air Stove Engineering Technology Co., Ltd. (hereinafter referred to as Yuxing Company) makes its emissions of nitrogen oxides, sulfur dioxide, and dust particles far lower than the new national standards issued this year. This is very important for the majority of iron-smelting enterprises. A timely rain to reduce the pressure on environmental protection, reduce costs and increase efficiency.

　　Innovatively developed low-nitrogen combustion technology for hot blast stoves

　　According to Liu Shiju, Chairman of Yuxing Company, Yuxing Hot Blast Stove Technology Research Center has been paying attention to the research of nitrogen oxide emission technology for many years, and has developed and implemented low-nitrogen combustion technology, which can effectively solve the pollution problem of high nitrogen emissions from hot blast stoves. The emission of toxic and harmful NOX is less than 50mg/m³, with an average of 32.83-42.83, which is 78.6%-83.5% less than the ultra-low emission standard 200mg/m³ stipulated by the Ministry of Ecology and Environment in 2019. This achievement has found a way out and a reliable scientific basis for the high equipment investment and high operating cost of the hot blast stove desulfurization and denitrification deep treatment of ultra-low emissions, and has been welcomed by iron smelters. This move is more in response to the call of General Secretary Xi Jinping that "green water and green mountains are golden mountains and silver mountains", and has made a great contribution to changing the ecological environment and benefiting mankind.

　　Yuxing's ultra-low emission hot blast stove low-nitrogen combustion comprehensive technology can completely achieve ultra-low emissions of toxic gases from the hot blast stove combustion technology itself and the structural performance of the equipment without investing in denitrification treatment and without increasing costs. , Can significantly reduce the investment cost and operating cost of iron-smelting enterprises, and effectively ensure environmental protection and corporate benefits.

　　Four technologies kill two birds with one stone

　　The key technology of ultra-low emission of nitrogen oxides of Yuxing Technology R&D Center-low-nitrogen combustion comprehensive technology research and development began 9 years ago. The specific technology and implementation points are as follows:

　　——Allow gas and air to enter their corresponding loops. Because the walls and burner loop walls in the air supply and heating periods are in a high temperature state, the gas and air entering the loop are preheated by the wall once. When the gas and air staggered into the edge of the large wall of the regenerator, the lower end of the vault, the jet set above the vault is sprayed at a high speed of 25-35 meters per second, and the sprayed gas and air form a low-temperature air curtain. It just separates the high temperature and high temperature area from the refractory lining of the dome. While protecting the dome lining from high temperature and scouring, the low temperature air curtain is preheated by high temperature radiation heating, so that the gas and air that do not reach the mixed part are preheated. The preheating temperature of the air curtain layer is as high as 500-1000 degrees Celsius. Through this important third preheating, the theoretical combustion temperature of the sprayed gas and air has been effectively increased, and the air temperature has been increased.

　　——Using long flame pre-mixed combustion and upward spraying, through the action of the negative pressure of the chimney, the two gas sprayed upwards are sprayed to the top of the vault and turned back down into the regenerator bed surface to form a natural vortex, which has achieved the above On the basis of preheating, the high-temperature gas is then turned back to form a vortex secondary air flow to stir and mix, to achieve a better effect of mixing and combustion.

　　——Because of the preheating and vortex agitation performance, the swirling flow is specially set up during the upward spraying process, and the swirling flow moves very intensely on the top, due to the secondary gas mixing and swirling effect of the vortex flow. Stir and mix three times to make the gas and air mix more evenly and achieve the ultimate goal of complete combustion.

　　——While achieving uniform mixed combustion, high air temperature is implemented due to the combined effect of the heat storage and heat exchange capacity of checker bricks and the reduction of the vault temperature. Among them, the flue gas flow field and the cold air flow field of the checker brick cross section are evenly distributed pressure and flow checker bricks,

　　Through the above 4 kinds of technical measures, the hot blast stove not only achieves a good high air temperature effect, but also achieves low nitrogen emissions, which can be described as killing two birds with one stone.

　　Innovative technology blossoms and bears fruit in the enterprise

　　The new low-nitrogen emission technology developed by Yuxing Company has blossomed in the enterprise. For example, on July 10, 2012, the Yuxing catenary top-fired hot blast stove supporting the 1860m³ blast furnace of Jianbang Tongcai No. 3 in Shanxi, which was put into operation on July 10, 2012, achieved a historical record of high wind temperature of 1314.7℃ per month on October 11 of that year. Has not been surpassed so far. It uses the above-mentioned comprehensive technology (checker brick is a conventional checker brick with 30 mm diameter and 19 holes). With an average dome temperature of 1409°C, and a 94°C difference between the dome temperature and the air supply temperature, nitrogen oxides can be greatly reduced, because the dome temperature generated by nitrogen oxides is greater than 1420°C. In 2013, the research team of Cheng Shusen, a professor at the University of Science and Technology Beijing, conducted field tests on this group of hot blast stoves. The test results showed that the amount of nitrogen oxides produced was 83mg/m³. Created a historical record for the generation of low nitrogen oxides.

　　Yuxing catenary top-fired hot blast stoves are the most distributed in Hebei Province and are the most representative, especially Hebei Jingye Iron and Steel Company. At present, there are 34 Yuxing catenary top-fired hot blast stoves that have long-term high blast temperatures. run. The test target is the smoke composition of the hot blast stove in the burning state. The test cycle is a 60-minute combustion cycle. The average test is performed every 10 minutes, and the average value is used as the unit. The test results show that the vault temperature of the hot blast stove in the combustion state is below 1300 ℃, and the air supply temperature is above 1215 ℃. The nitrogen oxides measured by the three blast furnace hot blast stoves for five times in a combustion cycle are all maintained at 36mg/m³, 37mg/m³, 33mg/m³, 40mg/m³, 37mg/m³, 37mg/m³, which are completely lower than the national ultra-low emission targets.

　　除了河北敬业钢铁公司外，豫兴公司还委托权威检测机构对河北奥森钢铁公司、河北纵横丰南钢铁公司、唐山瑞丰钢铁公司、秦皇岛安丰钢铁公司等五家单位的十座高炉配套的30多座豫兴悬链线顶燃式热风炉烟气成分进行了现场实测，测得烟气成分中氮氧化物排放至如下表;

　　委托第三方权威机构测试豫兴悬链线顶燃式热风炉NOx数据统计表

　　(用户建议此表一定采用，比纯文字报道更能说明文题)

　　从目前情况看，豫兴公司顶燃式热风炉可以使炼铁厂不用考虑建设脱硝治理设备就能满足2019年国家生态环境部提出的200mg/m³以下的氮排放标准。豫兴公司热风炉综合低氮燃烧综合技术的成功经验，为我国炼铁高炉配套的热风炉在使用、建设、设计中避免有毒气体污染环境，实施超低排放，提供了科学的依据，也为炼铁厂节能降本做了十分有益的贡献。