钢铁烧结工艺氧化脱硝的模拟试验及工程试验

发布时间：2018-07-04 07:37

  本文选题：烧结烟气 + 氧化脱硝　； 参考：《东南大学》2015年硕士论文

【摘要】：氮氧化物(NO_x)是钢铁企业所排放的主要大气污染物之一,其中钢铁烧结工序所产生的NO_x约占整个钢铁冶炼主工序的48%左右,是钢铁企业NO_x排放控制的重点。目前全国大部分钢铁企业烧结生产线都配有烧结烟气脱硫设施,却没有配套的脱硝设备,造成的NO_x污染问题日趋严重。一方面由于烧结工序所采用的的燃料变化大,烧结矿原料品质参差不齐,造成了烧结烟气具有温度低且变化范围大、NO_x浓度低波动大、含氧量和含湿量大等特点。不适宜直接采用普通燃煤电厂的脱硝方法；另一方面由于燃煤电厂的烟气脱硝与脱硫是分开进行的,这种传统的分别脱硫脱硝技术存在设备投资和运行费用高,占地面积大等不足,为此,本文开展了烧结烟气氧化脱硝的实验室模拟试验研究和工程试验,旨在不影响脱硫效率的前提下,在原有的烧结烟气脱硫工艺中加入合适的氧化剂,达到NO_x减排的目的。对不同的氧化剂进行分析筛选,选取了NaClO及KMnO_4/NaClO/Ca(OH)_2组合为烧结烟气氧化脱硝实验室模拟试验研究的氧化剂。构建以南京钢铁厂2x180m2烧结工序脱硫工艺为原型的旋转喷雾模拟试验平台,进行NaClO/Ca(OH)_2溶液体系和KMnO_4/NaClO/Ca(OH)_2溶液体系的烧结烟气氧化脱硝实验室模拟试验研究,考察了氧化剂溶液pH、模拟烟气温度、氧化剂浓度、SO_2浓度及NO浓度这些操作参数对脱除效率的影响,并对NaClO/Ca(OH)_2溶液体系和KMnO_4/NaClO/Ca(OH)_2组合溶液体系烧结烟气氧化脱硝的实验室模拟试验的过程进行了热力学计算和试验机理分析。试验及分析结果表明,NaClO/Ca(OH)_2溶液体系的实验室模拟试验最佳工况为pH=10、Tg=60℃、ms=6mmo/L,在此条件下的平均脱硫脱硝效率分别能够达到98.8%和60.1%;KMnO_4/NaClO/Ca(OH)_2溶液体系的最佳工况为pH=5.5、模拟烟气温度Tg=50℃、KMnO_4/NaClO摩尔比为3(即mp=0.1mmo/L,ms=0.3mmo/L),在此条件下的平均脱硫脱硝效率分别能够达到98.8%和70.9%。在南京钢铁厂2x180m2烧结工序的旋转喷雾脱硫塔上分别进行了NaClO/Ca(OH)_2溶液体系和KMnO_4/NaClO/Ca(OH)_2溶液体系的烧结烟气氧化脱硝的工程试验,试验结果表明,在氧化剂溶液pH为10、NaClO浓度(ms)为6mmo/L、Ca(OH)_2含固量为30%的条件下,采用NaC10/Ca(OH)_2溶液体系进行工程试验的平均脱硝率为20%,脱硫率则能达到98%以上：在氧化剂溶液pH为5.5、KMnO_4/NaClO摩尔比为3(即mp=0.1mmo/L,ms=0.3mmo/L)、Ca(OH)_2含固量为30%的条件下,采用KMnO_4/NaClO/Ca(OH)_2溶液体系进行工程试验的平均脱硫脱硝效率分别能够达到98%和30%。两种情况下的原有烧结烟气脱硫效率均没有因为加入了氧化剂而受到影响,说明了在烧结烟气旋转喷雾脱硫的工艺中加入氧化剂NaClO/Ca(OH)_2或者KMnO_4/NaClO/Ca(OH)_2组合进行烧结烟气氧化脱硝的方案是可行的,不仅不会影响原有设备的烟气脱硫效率,还能够减少氮氧化物(NO_x)的排放,达到脱硫脱硝一体化的目的。
[Abstract]:No _ x (no _ x) is one of the main atmospheric pollutants emitted by iron and steel enterprises, in which the no _ x produced in the sintering process of iron and steel accounts for about 48% of the total main process of iron and steel smelting, which is the key point of Nox emission control in iron and steel enterprises. At present, most iron and steel enterprise sintering production lines are equipped with sintering flue gas desulphurization facilities, but there is no supporting denitrification equipment, resulting in serious NOX pollution problem. On the one hand, because the fuel used in sintering process changes greatly and the raw material quality of sinter is not uniform, the sintering flue gas has the characteristics of low temperature and large range of variation, large fluctuation of NOX concentration, high oxygen content and moisture content, etc. On the other hand, because the flue gas denitrification and desulphurization of coal-fired power plants are carried out separately, the traditional separate desulphurization and denitrification technology has high equipment investment and running cost. Therefore, the laboratory simulation and engineering experiments of oxidizing denitrification of sintered flue gas are carried out in order to add suitable oxidant to the original sintering flue gas desulfurization process without affecting the desulfurization efficiency. To achieve the purpose of reducing NOX emissions. Different oxidants were analyzed and screened, and NaClO and KMnOs 4 / NaClO / Ca (OH) _ 2 were selected as oxidants for the laboratory simulation study of oxidation and denitrification of sintered flue gas. Based on the 2x180m2 sintering process desulfurization process in Nanjing Iron and Steel Plant, a rotating spray simulation test platform was built to simulate the oxidation and denitrification of flue gas in the system of NaClO / Ca (OH) _ 2 solution and KMnO _ (4) / NaClO / Ca (OH) _ 2 solution system. The effects of pH of oxidant solution, simulated flue gas temperature, so _ 2 concentration and no concentration on removal efficiency were investigated. Thermodynamic calculation and experimental mechanism analysis were carried out on the laboratory simulation test of oxidation denitrification of flue gas in NaClO / Ca (OH) _ 2 solution system and KMnO _ (4) / NaClO / Ca (OH) _ 2 composite solution system. The results of experiment and analysis show that the optimum condition of laboratory simulation test for the solution system of NaClO / Ca (OH) 2 is pH 10 ~ (10) TG ~ (60) 鈩，

本文编号：2095316