铁矿石烧结过程中不同类型准颗粒的燃烧特性
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摘要
采用竖直管式炉研究了焦炭粒径、黏附层、黏附比、焦粉比例对不同类型准颗粒质量转化率和燃料氮转化率的影响.结果表明,对于S和S'型准颗粒,质量转化率均随焦炭粒径的增大而降低;对于S'型准颗粒,燃料氮转化率随着焦炭粒径的增大而减小,而对于存在黏附层的S型准颗粒,内核焦炭粒径越大,燃料氮转化率越大;通过对比S和S'型准颗粒的燃烧情况,发现黏附层的存在有利于提高准颗粒的质量转化率和燃料氮转化率;对于C型准颗粒,黏附比越大,质量转化率和燃料氮转化率均越小; P型准颗粒的质量转化率随着焦粉比例的增加而减小,燃料氮转化率在焦粉比例为50%时达到最低值.
The iron ore sintering process is the main source of NOxemissions and accounts for about 48% of the total NOxemissions in the iron and steel industry. The generated NOxis mainly from fuel consumption,and it usually exists in the form of quasi-particle in iron ore sintering bed. Therefore,it is important to deeply understand the combustion characteristics and NOxformation mechanism of quasi-particles in iron ore sintering process. Based on this,the effects of coke breeze particle size,presence of an adhering layer of quasi-particles,adhering ratio of quasi-particle,and coke breeze content on the mass conversion rate of different types of quasiparticles and conversion rate of fuel-N to NOxwere investigated in a vertical quartz tube reactor in detail. The results show that the mass conversion rate decreases with increasing coke breeze particle size for S'-and S-type quasi-particles; the conversion rate of fuel-N to NOxdecreases with increasing coke breeze particle size for S'-type quasi-particle and exhibits the opposite trend for S-type quasi-particle,which is because of the presence of an adhering layer consisting of fine iron ore and limestone. Considering the combustion characteristics of S-and S'-type quasi-particles,the presence of an adhering layer of quasi-particles favors the increase of mass conversion rate and conversion rate of fuel-N to NOx. The mass conversion rate and conversion rate of fuel-N to NOxboth decrease with increasing adhering ratio for C-type quasi-particles whose adhering layer consists of fine limestone and coke breeze. For P-type quasi-particles comprising coke breeze,fine limestone,and fine iron ore,the mass conversion rate decreases with increasing coke breeze content. The conversion rate of fuel-N to NOxis not linear and reaches the lowest value when coke breeze content is 50%.
The iron ore sintering process is the main source of NOxemissions and accounts for about 48% of the total NOxemissions in the iron and steel industry. The generated NOxis mainly from fuel consumption,and it usually exists in the form of quasi-particle in iron ore sintering bed. Therefore,it is important to deeply understand the combustion characteristics and NOxformation mechanism of quasi-particles in iron ore sintering process. Based on this,the effects of coke breeze particle size,presence of an adhering layer of quasi-particles,adhering ratio of quasi-particle,and coke breeze content on the mass conversion rate of different types of quasiparticles and conversion rate of fuel-N to NOxwere investigated in a vertical quartz tube reactor in detail. The results show that the mass conversion rate decreases with increasing coke breeze particle size for S'-and S-type quasi-particles; the conversion rate of fuel-N to NOxdecreases with increasing coke breeze particle size for S'-type quasi-particle and exhibits the opposite trend for S-type quasi-particle,which is because of the presence of an adhering layer consisting of fine iron ore and limestone. Considering the combustion characteristics of S-and S'-type quasi-particles,the presence of an adhering layer of quasi-particles favors the increase of mass conversion rate and conversion rate of fuel-N to NOx. The mass conversion rate and conversion rate of fuel-N to NOxboth decrease with increasing adhering ratio for C-type quasi-particles whose adhering layer consists of fine limestone and coke breeze. For P-type quasi-particles comprising coke breeze,fine limestone,and fine iron ore,the mass conversion rate decreases with increasing coke breeze content. The conversion rate of fuel-N to NOxis not linear and reaches the lowest value when coke breeze content is 50%.
引文
[1] Long H M. Research and Application on Sintering Thermal State Model of Iron Ore[Dissertation]. Changsha:Central South University,2007(龙红明.铁矿石烧结过程热状态模型的研究与应用[学位论文].长沙:中南大学,2007)
[2] Ohno K I,Noda K,Nishioka K,et al. Combustion rate of coke in quasi-particle at iron ore sintering process. ISIJ Int,2013,53(9):1588
[3] World metals. Global crude steel production in 2016 return to growth.(2017-02-18)[2018--01--15]. http://www. worldmetals. com. cn/viscms/xingyeyaowen3686/240285. jhtml.(世界金属导报. 2016年全球粗钢产量重回增长轨道.(2017-02--18)[2018-01--15]. http://www. worldmetals. com. cn/viscms/xingyeyaowen3686/240285. jhtml)
[4] Liu D J,Wei Y Q,Yang L Q. Research of emission reduction situation of nitrogen oxides in China’s iron and steel enterprises. Environ Eng,2012,30(5):118(刘大钧,魏有权,杨丽琴.我国钢铁生产企业氮氧化物减排形势研究.环境工程,2012,30(5):118)
[5] Hill S C,Smoot L D. Modeling of nitrogen oxides formation and destruction in combustion systems. Prog Energy Combust Sci,2000,26(4-6):417
[6] Zhou H,Zhou M X,Liu Z H,et al. Modeling NOxemission of coke combustion in iron ore sintering process and its experimental validation. Fuel,2016,179:322
[7] Loo C E. Role of coke size in sintering of hematite ore blend.Ironmaking Steelmaking,1991,18(1):33
[8] Teo C S,Mikka R A,Loo C E. Positioning coke particles in iron ore sintering. ISIJ Int,1992,32(10):1047
[9] Hida Y,Sasaki M,Enokido T,et al. Effect of the existing state of coke breeze in quasi-particles of raw mix on coke combustion in the sintering process. Tetsu-to-Hagane,1982,68(3):400(肥田行博,佐々木稔,榎戸恒夫,等.焼結鉱製造過程でのコークス燃焼におよぼす擬似粒子中コークス賦存状態の影響.鉄と鋼,1982,68(3):400)
[10] Ogi H,Maeda T,Ohno K I,et al. Effect of coke breeze distribution on coke combustion rate of the quasi-particle. ISIJ Int,2015,55(12):2550
[11] Arikata Y,Yamamoto K,Sassa Y. Effect of coke breeze addition timing on sintering operation. ISIJ Int,2013,53(9):1523
[12] Oba Y,Konishi H,Ono H,et al. Combustion behavior of coated cokes with fine Fe3O4and CaO. Tetsu-to-Hagane,2017,103(6):299(大場雄介,小西宏和,小野英樹,等.粉末Fe3O4とCaOで被覆したコークスの燃焼挙動.鉄と鋼,2017,103(6):299)
[13] Gan M,Fan X H,Lv W,et al. Fuel pre-granulation for reducing NOx,emissions from the iron ore sintering process. Powder Technol,2016,301:478
[14] Gan M,Fan X H,Ji Z Y,et al. Effect of distribution of biomass fuel in granules on iron ore sintering and NOxemission. Ironmaking Steelmaking,2014,41(6):430
[15] Hou P,Choi S,Choi E,et al. Improved distribution of fuel particlesin iron ore sintering process. Ironmaking Steelmaking,2011,38(5):379
[16] Terushige N,Masanori N,Tetsuya N. Effect ofgranule structure on the combustion behavior of coke breeze//Proceedings of the5th International Congress on the Science and Technology of Ironmaking. Shanghai,2009:198
[17] Tobu Y,Nakano M,Nakagawa T,et al. Effect of granule structure on the combustion behavior of coke breeze for iron ore sintering. ISIJ Int,2013,53(9):1594
[18] Kasai E,Omori Y. Combustion rate of coke at different existing states prepared by fine alumina. Tetsu-to-Hagane,1986,72(10):1537(葛西栄輝,大森康男.アルミナを擬似鉱石とした賦存状態の異なるコークスの充填層内燃焼速度.鉄と鋼,1986,72(10):1537)
[19] Zhao J P,Loo C E,Dukino R D. Modelling fuel combustion in iron ore sintering. Combust Flame,2015,162(4):1019
[20] Kasai E,Wu S L,Sugiyama T,et al. Combustion rate and NO emission during combustion of coke granules in packed beds. ISIJ Int,1992,78(7):1005
[21] Kasai E,Saito F. Reduction of nitrogen oxides emission from the iron ore sintering process by optimizing the structure of carbonaceous fuels. Kagaku Kōgaku Ronbunshū,Akita-ken,1994:857(葛西栄輝,齋藤文良.鉄鉱石焼結プロセスにおける炭材燃料構造の最適化による窒素酸化物発生量の低減.化学工学論文集,秋田,1994:857)
[22] Katayama K,Kasama S. Influence of lime coating coke on NOx concentration in sintering process. ISIJ Int,2016,56(9):1563
[23] Duan W J,Yu Q B,Wu T W,et al. The steam gasification of coal with molten blast furnace slag as heat carrier and catalyst:Kinetic study. Int J Hydrogen Energy,2016,41(42):18995
[2] Ohno K I,Noda K,Nishioka K,et al. Combustion rate of coke in quasi-particle at iron ore sintering process. ISIJ Int,2013,53(9):1588
[3] World metals. Global crude steel production in 2016 return to growth.(2017-02-18)[2018--01--15]. http://www. worldmetals. com. cn/viscms/xingyeyaowen3686/240285. jhtml.(世界金属导报. 2016年全球粗钢产量重回增长轨道.(2017-02--18)[2018-01--15]. http://www. worldmetals. com. cn/viscms/xingyeyaowen3686/240285. jhtml)
[4] Liu D J,Wei Y Q,Yang L Q. Research of emission reduction situation of nitrogen oxides in China’s iron and steel enterprises. Environ Eng,2012,30(5):118(刘大钧,魏有权,杨丽琴.我国钢铁生产企业氮氧化物减排形势研究.环境工程,2012,30(5):118)
[5] Hill S C,Smoot L D. Modeling of nitrogen oxides formation and destruction in combustion systems. Prog Energy Combust Sci,2000,26(4-6):417
[6] Zhou H,Zhou M X,Liu Z H,et al. Modeling NOxemission of coke combustion in iron ore sintering process and its experimental validation. Fuel,2016,179:322
[7] Loo C E. Role of coke size in sintering of hematite ore blend.Ironmaking Steelmaking,1991,18(1):33
[8] Teo C S,Mikka R A,Loo C E. Positioning coke particles in iron ore sintering. ISIJ Int,1992,32(10):1047
[9] Hida Y,Sasaki M,Enokido T,et al. Effect of the existing state of coke breeze in quasi-particles of raw mix on coke combustion in the sintering process. Tetsu-to-Hagane,1982,68(3):400(肥田行博,佐々木稔,榎戸恒夫,等.焼結鉱製造過程でのコークス燃焼におよぼす擬似粒子中コークス賦存状態の影響.鉄と鋼,1982,68(3):400)
[10] Ogi H,Maeda T,Ohno K I,et al. Effect of coke breeze distribution on coke combustion rate of the quasi-particle. ISIJ Int,2015,55(12):2550
[11] Arikata Y,Yamamoto K,Sassa Y. Effect of coke breeze addition timing on sintering operation. ISIJ Int,2013,53(9):1523
[12] Oba Y,Konishi H,Ono H,et al. Combustion behavior of coated cokes with fine Fe3O4and CaO. Tetsu-to-Hagane,2017,103(6):299(大場雄介,小西宏和,小野英樹,等.粉末Fe3O4とCaOで被覆したコークスの燃焼挙動.鉄と鋼,2017,103(6):299)
[13] Gan M,Fan X H,Lv W,et al. Fuel pre-granulation for reducing NOx,emissions from the iron ore sintering process. Powder Technol,2016,301:478
[14] Gan M,Fan X H,Ji Z Y,et al. Effect of distribution of biomass fuel in granules on iron ore sintering and NOxemission. Ironmaking Steelmaking,2014,41(6):430
[15] Hou P,Choi S,Choi E,et al. Improved distribution of fuel particlesin iron ore sintering process. Ironmaking Steelmaking,2011,38(5):379
[16] Terushige N,Masanori N,Tetsuya N. Effect ofgranule structure on the combustion behavior of coke breeze//Proceedings of the5th International Congress on the Science and Technology of Ironmaking. Shanghai,2009:198
[17] Tobu Y,Nakano M,Nakagawa T,et al. Effect of granule structure on the combustion behavior of coke breeze for iron ore sintering. ISIJ Int,2013,53(9):1594
[18] Kasai E,Omori Y. Combustion rate of coke at different existing states prepared by fine alumina. Tetsu-to-Hagane,1986,72(10):1537(葛西栄輝,大森康男.アルミナを擬似鉱石とした賦存状態の異なるコークスの充填層内燃焼速度.鉄と鋼,1986,72(10):1537)
[19] Zhao J P,Loo C E,Dukino R D. Modelling fuel combustion in iron ore sintering. Combust Flame,2015,162(4):1019
[20] Kasai E,Wu S L,Sugiyama T,et al. Combustion rate and NO emission during combustion of coke granules in packed beds. ISIJ Int,1992,78(7):1005
[21] Kasai E,Saito F. Reduction of nitrogen oxides emission from the iron ore sintering process by optimizing the structure of carbonaceous fuels. Kagaku Kōgaku Ronbunshū,Akita-ken,1994:857(葛西栄輝,齋藤文良.鉄鉱石焼結プロセスにおける炭材燃料構造の最適化による窒素酸化物発生量の低減.化学工学論文集,秋田,1994:857)
[22] Katayama K,Kasama S. Influence of lime coating coke on NOx concentration in sintering process. ISIJ Int,2016,56(9):1563
[23] Duan W J,Yu Q B,Wu T W,et al. The steam gasification of coal with molten blast furnace slag as heat carrier and catalyst:Kinetic study. Int J Hydrogen Energy,2016,41(42):18995
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