烧结矿催化还原NO的实验研究
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摘要
《钢铁企业超低排放改造工作方案(征求意见稿)》中,计划将烧结烟气中NO_x排放质量浓度控制在50 mg/m~3以内,烧结烟气NO_x减排势在必行。因此,旨在利用烧结矿本身作为脱硝催化剂,以烧结过程产生的还原性气体CO为还原剂,系统地研究了烧结矿粒径、焙烧温度、空速比、CO/NO物质的量之比和O_2体积分数对烧结矿催化脱硝效果的影响。结果表明,O_2体积分数对烧结矿催化还原NO的转化率影响较大,当CO体积分数为3%、O_2体积分数为1.04%时,NO的转化率为68.83%;O_2体积分数降低至0.90%以下时,NO的转化率可达95%以上。无O_2条件下,烧结矿粒径为0.2～1.0 mm、焙烧温度为500℃、空速比为3 000 h~(-1)、CO/NO物质的量之比为6时,NO的转化率可达99.58%。以烧结矿为催化剂能有效地促进CO对NO的还原,具有十分重要的环保意义和经济应用前景。
In the Work Plan for Ultra-low Emission Reduction of Iron and Steel Enterprises(Draft for Soliciting Opinions), it is planned to control the concentration of NO_x emission in sintered flue gas below 50 mg/m~3, so it is imperative to reduce NO_x emission of sintered flue gas. With the sinter itself as a denitration catalyst and reducing gas CO produced in the sintering process as a reducing agent, the effects of particle size, roasting temperature, space velocity, CO/NO mole fraction ratio and O_2 volume fraction on catalytic denitration of sinter were systematically investigated. The results show that the volume fraction of O_2 has a great influence on the conversion rate of NO in catalytic reduction of sinter; when the volume fractions of CO and O_2 are 3% and 1.04%, respectively, the NO conversion rate can reach 68.83%. When the volume fraction of O_2 decreases below 0.90%, the conversion rate of NO can reach 95%. Under the conditions of no O_2, the sinter size of 0.2-1.0 mm, the temperature of 500 ℃, the space velocity of 3 000 h~(-1), and the CO/NO mole fraction ratio of 6, the conversion rate of NO can reach 99.58%. The application of sinter as catalyst can effectively promote the reduction of CO to NO, which has very important environmental protection significance and economic application prospect.
In the Work Plan for Ultra-low Emission Reduction of Iron and Steel Enterprises(Draft for Soliciting Opinions), it is planned to control the concentration of NO_x emission in sintered flue gas below 50 mg/m~3, so it is imperative to reduce NO_x emission of sintered flue gas. With the sinter itself as a denitration catalyst and reducing gas CO produced in the sintering process as a reducing agent, the effects of particle size, roasting temperature, space velocity, CO/NO mole fraction ratio and O_2 volume fraction on catalytic denitration of sinter were systematically investigated. The results show that the volume fraction of O_2 has a great influence on the conversion rate of NO in catalytic reduction of sinter; when the volume fractions of CO and O_2 are 3% and 1.04%, respectively, the NO conversion rate can reach 68.83%. When the volume fraction of O_2 decreases below 0.90%, the conversion rate of NO can reach 95%. Under the conditions of no O_2, the sinter size of 0.2-1.0 mm, the temperature of 500 ℃, the space velocity of 3 000 h~(-1), and the CO/NO mole fraction ratio of 6, the conversion rate of NO can reach 99.58%. The application of sinter as catalyst can effectively promote the reduction of CO to NO, which has very important environmental protection significance and economic application prospect.
引文
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[17] Mo C L,Teo C S,Hamilton I,et al.Admixing hydrocarbons in raw mix to reduce NOx emission in iron ore sintering process[J].ISIJ International,1997,37(4):350.
[18] 高继贤,刘静,曾艳,等.活性焦(炭)干法烧结烟气净化技术在钢铁行业的应用与分析(Ⅰ)—工艺与技术经济分析[J].烧结球团,2012,37(1):65.(Gao J X,Liu J,Zeng Y,et al.Application and analysis of dry activated coke(carbon)sintering flue gas purification technology in iron and steel industry—process and technical and economical analysis[J].Sintered Pellets,2012,37(1):65.)
[19] 陈铁军,万军营,周仙霖,等.一种多污染物减排的双层点火烧结方法:中国,CN108611486A[P].2018-10-02.(Chen T J,Wan J Y,Zhou X L,et al.A Double-layer Ignition Sintering Method for Reducing Multiple Pollutants:China,CN108611486A[P].2018-10-02.)
[20] 潘建.铁矿烧结烟气减量排放基础理论与工艺研究[D]//长沙:中南大学,2007.(Pan J.Research of Basic Theory and Technology on Reducing the Emissions of Iron Ore Sintering Flue Gas[D]//Changsha:Central South University,2007.)
[21] 贾小彬.粉煤灰-凹凸棒石负载锰氧化物催化剂低温SCR脱硝性能研究[D]//合肥:合肥工业大学,2013.(Jia X B.Low-temperature Telective Catalytic Reduction of NO with NH3 over Fly Ash-palygorskite Supported Manganese Oxides Catalysts[D]//Hefei:Hefei University of Technology,2013.)
[22] 李宏扬.烧结过程氮氧化物减量化实验研究[D]//昆明:昆明理工大学,2015.(Li H Y.Experimental Study of NOx Reduction in the Sintering Process[D]//Kunming:Kunming University of Science and Technology,2015.)
[23] 陈彦广,郭占成,王志.烧结过程中CO还原NO的模拟研究[J].钢铁研究学报,2009,21(1):6.(Chen Y G,Guo Z C,Wang Z.Simulation of NO reduction by CO in sintering process[J].Journal of Iron and Steel Research,2009,21(1):6.)
[24] 周浩生,陆继东,周琥,等.一氧化碳作用下铁对一氧化氮的催化还原实验与动力学过程分析[J].热能动力工程,2002,17(1):86.(Zhou H S,Lu J D,Zhou H,et al.Experimental and kinetics process analysis of NO catalytic reduction by iron under the action of CO[J].Thermal Power Engineering,2002,17(1):86.)
[25] Hayhurst A N,Lawrence A D.The reduction of the nitrogen oxides NO and N2O to molecular nitrogen in the presence of iron,its oxides,and carbon monoxide in a hot fluidized bed[J].Combustion and Flame,1997,110(3):351.
[26] Pegoretti V C B,Couceiro P R C,Gon?倞alves C M,et al.Preparation and characterization of tin-doped spinel ferrite[J].Journal of Alloys and Compounds,2010,505(1):125.
[27] 张浩.铁系金属氧化物催化还原NOx性能研究[D]//哈尔滨:哈尔滨工程大学,2007.(Zhang H.Study on Catalytic Reduction of NOx by Iron Oxides[D]//Harbin:Harbin Engineering University,2007.)
[28] 苏亚欣,苏阿龙,成豪.金属铁直接催化还原NO的实验研究[J].煤炭学报,2013,38(S1):209.(Su Y X,Su A L,Cheng H.Experimental study on direct catalytic reduction of NO by metallic iron[J].Journal of Coal,2013,38(S1):209.)
[2] Yang K,Dickerson R R,Carn S A,et al.First observations of SO2 from the satellite Suomi NPP OMPS:Widespread air pollution events over China[J].Geophysical Research Letters,2013,40(18):4957.
[3] 于超,王书肖,郝吉明.基于模糊评价方法的燃煤电厂氮氧化物控制技术评价[J].环境科学,2010,31(7):1464.(Yu C,Wang S X,Hao J M.Comprehensive fuzzy evaluation of nitrogen oxide control technologies for coal-fired power plants[J].Environmental Science,2010,31(7):1464.)
[4] 王萌,苏艺.钢铁工业节能减排技术及其在国内的应用[J].环境工程,2010,28(2):59.(Wang M,Su Y.The technologies of energy conservation and emission reduction in iron and steel industry and their application in China[J].Environmental Engineering,2010,28(2):59.)
[5] 廖继勇,储太山,刘昌齐,等.烧结烟气脱硫脱硝技术的发展与应用前景[J].烧结球团,2008,33(4):1.(Liao J Y,Chu T S,Liu C Q,et al.The development and application prospects of sintering gas desulphurization and denitration technology[J].Sintered Pellets,2008,33(4):1.)
[6] 刘传鹏,杨东伟,惠建明,等.烧结余热梯级利用及脱硫脱硝一站式解决方案[J].钢铁研究学报,2016,28(10):50.(Liu C P,Yang D W,Hui J M,et al.One-stop solution of cascade utilization of waste heat recovery,desulfurization and denitrification in the sintering system[J].Journal of Iron and Steel Research,2016,28(10):50.)
[7] Yu Z Y,Fan X H,Gan M,et al.Effect of Ca-Fe oxides additives on NOx reduction in iron ore sintering[J].Journal of Iron and Steel Research International,2017,24(12):1184.
[8] Locci C,Vervisch L,Farcy B,et al.Selective non-catalytic reduction(SNCR)of nitrogen oxide emissions:A perspective from numerical modeling[J].Flow Turbulence and Combustion,2018,100(2):301.
[9] Mahmoudi S,Baeyens J,Seville J P K.NOx formation and selective non-catalytic reduction(SNCR)in a fluidized bed combustor of biomass[J].Biomass and Bioenergy,2010,34(9):1393.
[10] Bae S W,Roh S A,Kim S D.NO removal by reducing agents and additives in the selective non-catalytic reduction(SNCR)process[J].Chemosphere,2006,65(1):170.
[11] Long R Q,Yang R T,Chang R.Low temperature selective catalytic reduction(SCR)of NO with NH3 over Fe-Mn based catalysts[J].Chemical Communications,2002,5(5):452.
[12] Chong P C,Pyo Y D,Jin Y J,et al.NOx reduction and N2O emissions in a diesel engine exhaust using Fe-zeolite and vanadium based SCR catalysts[J].Applied Thermal Engineering,2017,110:18.
[13] Dong W K,Park K H,Hong S C.Enhancement of SCR activity and SO2resistance on VOx/TiO2 catalyst by addition of molybdenum[J].Chemical Engineering Journal,2016,284:315.
[14] 路涛,贾双燕,李晓芸.关于烟气脱硝的SNCR工艺及其技术经济分析[J].现代电力,2004,21(1):17.(Lu T,Jia S Y,Li X Y.Techno-economic analysis for process and application of SNCR[J].Modern Power,2004,21(1):17.)
[15] GarcíA-Bordejé E,Calvillo L,Lázaro M J,et al.Vanadium supported on carbon-coated monoliths for the SCR of NO at low temperature:Effect of pore structure[J].Applied Catalysis B:Environmental,2004,50(4):235.
[16] 陈健.烧结烟气氮氧化物减排技术路径探讨[J].环境工程,2014,32(s1):459.(Chen J.The discussion of sintering flue gas denitration technical path[J].Environmental Engineering,2014,32(s1):459.)
[17] Mo C L,Teo C S,Hamilton I,et al.Admixing hydrocarbons in raw mix to reduce NOx emission in iron ore sintering process[J].ISIJ International,1997,37(4):350.
[18] 高继贤,刘静,曾艳,等.活性焦(炭)干法烧结烟气净化技术在钢铁行业的应用与分析(Ⅰ)—工艺与技术经济分析[J].烧结球团,2012,37(1):65.(Gao J X,Liu J,Zeng Y,et al.Application and analysis of dry activated coke(carbon)sintering flue gas purification technology in iron and steel industry—process and technical and economical analysis[J].Sintered Pellets,2012,37(1):65.)
[19] 陈铁军,万军营,周仙霖,等.一种多污染物减排的双层点火烧结方法:中国,CN108611486A[P].2018-10-02.(Chen T J,Wan J Y,Zhou X L,et al.A Double-layer Ignition Sintering Method for Reducing Multiple Pollutants:China,CN108611486A[P].2018-10-02.)
[20] 潘建.铁矿烧结烟气减量排放基础理论与工艺研究[D]//长沙:中南大学,2007.(Pan J.Research of Basic Theory and Technology on Reducing the Emissions of Iron Ore Sintering Flue Gas[D]//Changsha:Central South University,2007.)
[21] 贾小彬.粉煤灰-凹凸棒石负载锰氧化物催化剂低温SCR脱硝性能研究[D]//合肥:合肥工业大学,2013.(Jia X B.Low-temperature Telective Catalytic Reduction of NO with NH3 over Fly Ash-palygorskite Supported Manganese Oxides Catalysts[D]//Hefei:Hefei University of Technology,2013.)
[22] 李宏扬.烧结过程氮氧化物减量化实验研究[D]//昆明:昆明理工大学,2015.(Li H Y.Experimental Study of NOx Reduction in the Sintering Process[D]//Kunming:Kunming University of Science and Technology,2015.)
[23] 陈彦广,郭占成,王志.烧结过程中CO还原NO的模拟研究[J].钢铁研究学报,2009,21(1):6.(Chen Y G,Guo Z C,Wang Z.Simulation of NO reduction by CO in sintering process[J].Journal of Iron and Steel Research,2009,21(1):6.)
[24] 周浩生,陆继东,周琥,等.一氧化碳作用下铁对一氧化氮的催化还原实验与动力学过程分析[J].热能动力工程,2002,17(1):86.(Zhou H S,Lu J D,Zhou H,et al.Experimental and kinetics process analysis of NO catalytic reduction by iron under the action of CO[J].Thermal Power Engineering,2002,17(1):86.)
[25] Hayhurst A N,Lawrence A D.The reduction of the nitrogen oxides NO and N2O to molecular nitrogen in the presence of iron,its oxides,and carbon monoxide in a hot fluidized bed[J].Combustion and Flame,1997,110(3):351.
[26] Pegoretti V C B,Couceiro P R C,Gon?倞alves C M,et al.Preparation and characterization of tin-doped spinel ferrite[J].Journal of Alloys and Compounds,2010,505(1):125.
[27] 张浩.铁系金属氧化物催化还原NOx性能研究[D]//哈尔滨:哈尔滨工程大学,2007.(Zhang H.Study on Catalytic Reduction of NOx by Iron Oxides[D]//Harbin:Harbin Engineering University,2007.)
[28] 苏亚欣,苏阿龙,成豪.金属铁直接催化还原NO的实验研究[J].煤炭学报,2013,38(S1):209.(Su Y X,Su A L,Cheng H.Experimental study on direct catalytic reduction of NO by metallic iron[J].Journal of Coal,2013,38(S1):209.)