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钒钛磁铁矿烧结过程氮氧化物减排控制技术研究
王建山
Thesis Advisor张树文
2018-07
Degree Grantor中国科学院研究生院
Degree Name硕士
Degree Discipline化学工程
Keyword烧结工艺,添加剂,No减排,过程控制
Abstract

2017年6月,国家环保部发布了《钢铁烧结、球团工业大气污染物排放标准》修改意见的公告,其中烧结烟气氮氧化物的排放限值由300mg/m3调整为100mg/m3。意见要求,“2+26”城市自2017年10月1日起执行,无组织排放控制措施自2019年1月1日执行,对现有企业给予一定的过渡期。随着环保要求的提高和更加严格排放标准的出台,钢铁行业正面临着加强控制NOX排放的挑战。本文着眼于钒钛磁铁矿烧结过程氮氧化物减量化排放处理,对烧结过程NO的来源、烧结工艺参数对NO生成影响、混合料中加入添加剂对NO生成影响等进行了系统的试验研究。利用加热炉试验系统研究各烧结原料燃烧时NO排放规律及温度、粒度、氧气浓度和空气流速等因素对焦炭燃烧时NO排放浓度的影响。试验结果表明:烧结混合料中的氮主要来源于燃料带入,其占总带入氮含量的73%;烧结原料在同一温度下燃烧时,煤粉和焦粉燃烧生成的NO浓度最高。随着燃烧温度的升高,焦炭燃烧时NO的转化率呈逐渐升高的趋势;随着粒度的增大,焦炭燃烧时NO的转化率则是先增高后下降,当粒度为3mm~5mm时,NO转化率达到最大值25.79%;随着O2含量的提高,焦炭燃烧时NO的转化率呈先升高后降低的趋势,在O2含量为15%时,NO转化率达到最大值30.2%;随着空气流速的增大,NO的转化率有逐渐降低的趋势。利用烧结杯试验系统研究烧结相关参数对NO生成及烧结主要指标的影响。研究表明:当混合料的碱度提高时,烟气中NO浓度有小幅降低的趋势,烧结速度、利用系数、烧结成品率和转鼓强度呈明显升高趋势;随着混合料水分的增大,烟气中NO浓度有小幅降低的趋势,烧结速度、利用系数略有升高,烧结成品率和转鼓强度呈下降趋势;随着活性灰所占熔剂比例的增大,烧结烟气中NO浓度有降低的趋势,烧结速度、成品率、转鼓强度、利用系数等指标均明显升高;随着料层厚度的增加,烧结烟气中NO浓度有降低的趋势,烧结矿成品率和转鼓指数逐渐增加,烧结速度和利用系数逐渐降低;随着煤粉和焦粉用量的降低,烧结烟气中NO浓度有显著的降低,成品率、转鼓强度逐渐降低;随着焦粉所占燃料比例的提高,烧结烟气中NO浓度有逐渐降低的趋势,烧结矿品位、成品率及烧结机利用系数均略有升高,烧结矿转鼓指数变化不明显。 利用烧结杯试验系统研究混合料中加入添加剂对NO生成及烧结主要指标的影响。试验结果表明:在烧结混合料中分别加入尿素、氯化铵、硫酸铵、碳酸铵及碳酸氢铵等挥发氨基类添加剂后,烟气中NO的排放总量都有一定幅度的降低,其中加入尿素及氯化铵的减排效果最好;当尿素的添加量增加到0.9wt%时,NO的排放总量从34.4g降低到22.4g,减排率达到36%;当氯化铵的添加量为0.7wt%时,NO的排放总量从34.4g降低到24.8g,减排率达到28%。在烧结混合料中加入乙酸钙等烃类添加剂后,烟气中NO的排放总量有明显的降低,随着乙酸钙添加量的增加,NO的排放总量呈先小幅降低后大幅降低的趋势,当乙酸钙的添加量达到0.9wt%时,NO的生成总量从34.4g降低到18.9g,减排率达到45%。在烧结混合料中加入生物质替代燃料后,烟气中NO的排放总量有显著的降低,随着替代比例的逐渐提高,NO的生成总量有逐渐降低的趋势,当燃料的替代比例达到50%时,NO的排放总量从34.4g降低到21.8g,减排率达到36.6%,但同时烧结速度、成品率、转鼓强度、利用系数等主要技术经济指标都有一定幅度的降低。;In June 2017, the Ministry of Environmental Protection issued an announcement on the amendment of the “Steel Sintering, Pellet Industrial Air Pollutant Emission Standards”, in which the emission limit of nitrogen oxides from sintering flue gas was adjusted from 300 mg/m3 to 100 mg/m3. It is required that the “2+26” cities shall be implemented since October 1, 2017, the unorganized emission control measures shall be implemented on January 1, 2019, giving a certain transition period to the existing enterprises. With the improvement of environmental protection requirements and the introduction of more stringent emission standards, the steel industry is facing the challenge of strengthening control of NOX emissions. This paper focuses on the reduction treatment of nitrogen oxides in the sintering process of vanadium-titanium magnetite, the source of NO during sintering, the influence of sintering process parameters on NO formation, and the effect of additives on the formation of NO in the mixture. A small horizontal reheating furnace test system was used to study the effect of NO Emission regularity and the influence of temperature, particle size, oxygen concentration and air velocity on the NO emission concentration during the combustion of the coke. The test results show that the main source of nitrogen in the sinter mixture comes from the fuel, which accounts for 73% of the total nitrogen content. When the sintering material is burned at the same temperature, the NO concentration of coal powder and coke powder is the highest. With the increase of combustion temperature, the conversion rate of NO increases gradually when coke is burned. With the increase of coke size, the conversion rate of NO increases first and then decreases. When the size of coke is 3mm~5mm, the conversion of NO reaches the maximum value of 25.79%. With the increase of O2 content, the conversion rate of NO increases first and then decreases, when the content of O2 is 15%, The conversion rate of NO reaches 30.2%, and the conversion rate of NO decreases with the increase of air velocity.The influence of sintering process parameters on NO generation and main indexes of sintering was studied by sintering cup test system. The test results show that with the increase of basicity of the sintering mixture, the concentration of NO in the flue gas decreases slightly, the sintering speed, the utilization coefficient, the sintering product rate and the drum strength are obviously increasing. With the increase of the mixture water, the concentration of NO in the flue gas has a slight decreasing trend, the sintering speed and the utilization coefficient are slightly higher, the sintering yield and the drum strength are decreasing. With the increase of the flux proportion of active ash, the concentration of NO in the sintering flue gas has a tendency to decrease, the sintering speed, the yield, the drum strength and the utilization coefficient are obviously increased. With the increase of the thickness of the material, the concentration of NO in the sintering flue gas has a tendency to decrease, the yield and the drum index of the sintered ore gradually increase, and the sintering speed and the utilization coefficient gradually decrease. With the coal sintering speed and the utilization coefficient gradually decreasing; along with coal. With the decrease of powder and coke powder, the concentration of NO in the sintering flue gas decreased significantly, the yield and drum strength decreased gradually, and the sintering utilization coefficient gradually increased first and then decreased. With the increase of the proportion of fuel in the coke powder, the concentration of NO in the sintering flue gas gradually decreased , and the sinter grade, the finished product rate and the sintering machine utilization coefficient increased slightly, and the sinter drum index did not change significantly.The influence of additives in the mixture on the main indicators of NO generation and sintering was studied by sintering cup test system. The results showed that after adding volatile ammonia, the total amount of NO emission in the flue gas decreased to a certain extent, and the effect of reducing the emission of urea and ammonium chloride was the best. With the increase of the amount of urea and ammonium chloride, the total amount of NO emission decreased gradually. When the amount of urea added to 0.9wt%, the total amount of NO emission decreased from 34.4g to 22.4g, and the emission reduction rate reached 36%. When the addition of ammonium chloride was 0.7wt%, the total amount of NO was reduced from 34.4g to 24.8g, and the emission reduction rate was 28%. After adding calcium acetate and other hydrocarbon additives in the sinter mixture, the total emission of NO in the flue gas decreased obviously. With the increase of calcium acetate addition, the total amount of NO emission decreased significantly after a small decrease. When the calcium acetate added to 0.9wt%, the total amount of NO decreased from 34.4g to 18.9g, and the emission reduction rate reached 45%. After adding the biomass substitute fuel to the sintering mixture, the total amount of NO emission in the flue gas is significantly reduced. With the increase of the fuel ratio, the total amount of NO is gradually reduced. When the replacement ratio of fuel reaches 50%, the total emission of NO is reduced from 34.4g to 21.8g, and the emission reduction rate is 36.6%, but the sintering speed, yield, drum strength and utilization coefficient are at the same time. The main technical and economic indicators have been reduced to a certain extent. 

Language中文
Document Type学位论文
Identifierhttp://ir.ipe.ac.cn/handle/122111/26913
Collection中国科学院过程工程研究所
研究所(批量导入)
Recommended Citation
GB/T 7714
王建山. 钒钛磁铁矿烧结过程氮氧化物减排控制技术研究[D]. 中国科学院研究生院,2018.
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