Combustion characteristics of different types of quasi-particles in iron ore sintering process
-
摘要: 采用豎直管式爐研究了焦炭粒徑、黏附層、黏附比、焦粉比例對不同類型準顆粒質量轉化率和燃料氮轉化率的影響.結果表明, 對于S和S'型準顆粒, 質量轉化率均隨焦炭粒徑的增大而降低; 對于S'型準顆粒, 燃料氮轉化率隨著焦炭粒徑的增大而減小, 而對于存在黏附層的S型準顆粒, 內核焦炭粒徑越大, 燃料氮轉化率越大; 通過對比S和S'型準顆粒的燃燒情況, 發現黏附層的存在有利于提高準顆粒的質量轉化率和燃料氮轉化率; 對于C型準顆粒, 黏附比越大, 質量轉化率和燃料氮轉化率均越小; P型準顆粒的質量轉化率隨著焦粉比例的增加而減小, 燃料氮轉化率在焦粉比例為50%時達到最低值.Abstract: The iron ore sintering process is the main source of NOx emissions and accounts for about 48% of the total NOx emissions in the iron and steel industry. The generated NOx is 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 NOx formation 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 NOx were 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 NOx decreases 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 NOx both 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 NOx is not linear and reaches the lowest value when coke breeze content is 50%.
-
圖 1 不同類型準顆粒示意圖. (a) S'型; (b) S型; (c) C型; (d) P型
Figure 1. Schematic diagram of different types of quasi-particles: (a) S'-type; (b) S-type; (c) C-type; (d) P-type
圖 2 不同類型的準顆粒. (a) S型; (b) P型; (c) C型; (d) S'型
Figure 2. Different types of quasi-particles: (a) S-type; (b) P-type; (c) C-type; (d) S'-type
圖 3 準顆粒燃燒試驗臺
Figure 3. Schematic diagram of the experimental rig for quasi-particle combustion
圖 4 體積分數變化曲線(P型, 入口氣體體積分數O2/N2為21%/79%, 爐膛溫度T=1000℃)
Figure 4. Volume fraction changes of flue gas components during P-type quasi-particle combustion at 1000℃and atmospheric O2to N2volume ratio of 21∶79
圖 5 粒徑變化對S'型準顆粒燃燒的影響. (a) 對質量轉化率的影響; (b) 對反應指數的影響; (c) 對燃料氮轉化率的影響
Figure 5. Effect of different coke sizes on the combustion characteristics of S'-type quasi-particles: (a) mass conversion rate; (b) reactivity index; (c) conversion rate of fuel-N to NOx
圖 6 內核粒徑對S型準顆粒燃燒的影響. (a) 對質量轉化率的影響; (b) 對反應指數的影響; (c) 對燃料氮轉化率的影響
Figure 6. Effect of different nuclei coke sizes on the combustion characteristics of S-type quasi-particles: (a) mass conversion rate; (b) reactivity in-dex; (c) conversion rate of fuel-N to NOx
圖 7 黏附層對準顆粒燃燒的影響. (a) 對質量轉化率的影響; (b) 對反應指數的影響; (c) 對燃料氮轉化率的影響
Figure 7. Effect of adhering layer on the combustion characteristics of quasi-particles: (a) mass conversion rate; (b) reactivity index; (c) conversion rate of fuel-N to NOx
圖 8 不同黏附比對C型準顆粒燃燒的影響. (a) 對質量轉化率的影響; (b) 對反應指數的影響; (c) 對燃料氮轉化的影響
Figure 8. Effect of different adhering ratios on the combustion characteristics of C-type quasi-particles: (a) mass conversion rate; (b) reactivity index; (c) conversion rate of fuel-N to NOx
圖 9 不同焦粉比例對P型準顆粒燃燒的影響. (a) 對質量轉化率的影響; (b) 對反應指數的影響; (c) 對燃料氮轉化率的影響
Figure 9. Effect of different coke breeze contents on the combustion characteristics of P-type quasi-particles: (a) mass conversion rate; (b) reactivity index; (c) conversion rate of fuel-N to NOx
表 1 不同類型準顆粒的組成和質量比
Table 1. Composition and mass ratio of different types of quasi-particles
類型 內核 黏附層 焦粉比例*/% 黏附比**/% 組分 粒徑/mm 組分 粒徑/mm S 焦炭 1.0~1.4;1.4~2.0;2.0~2.8 石灰石; 鐵礦石 -0.25 75 33.3 P — — 焦炭; 石灰石; 鐵礦石 -0.25 10，30，50，70，100 — C 鐵礦石 2.0~2.8 焦炭; 石灰石 -0.25 5，7.14，12.5 11.1，16.7，33.3 S' 焦炭 1.0~1.4，1.4~2.0，2.0~2.8 — — 100 0 
下載: 導出CSV
表 2 原料化學組分(質量分數)
Table 2. Chemical composition of raw materials ?
% 原料 Fe FeO Al2O3 SiO2 MgO CaO LOI1000* 鐵礦石 62.39 0.35 2.23 4.28 0.13 0.15 3.51 石灰石 0.36 0.10 0.98 2.23 0.48 53.40 42.00 焦炭 1.07 0 4.32 6.11 0.04 0.62 86.85 注: *表示樣品在1000 ℃下的燒失量.
下載: 導出CSV
中文字幕在线观看表 3 不同粒徑焦炭中氮元素質量分數
Table 3. Analysis of nitrogen content in coke of different particles sizes ?
% 1.0 ~ 1.4 mm 1.4 ~ 2.0 mm 2.0 ~ 2.8 mm -0.25 mm 0.92 0.95 0.92 0.86
下載: 導出CSV
-
參考文獻
[1] Long H M. Research and Application on Sintering Thermal State Model of Iron Ore[Dissertation]. Changsha: Central South University, 2007龍紅明. 鐵礦石燒結過程熱狀態模型的研究與應用[學位論文]. 長沙: 中南大學, 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 doi: 10.2355/isijinternational.53.1588 [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.世界金屬導報. 2016年全球粗鋼產量重回增長軌道. (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 doi: 10.3969/j.issn.1671-1556.2012.05.030劉大鈞, 魏有權, 楊麗琴. 我國鋼鐵生產企業氮氧化物減排形勢研究. 環境工程, 2012, 30(5): 118 doi: 10.3969/j.issn.1671-1556.2012.05.030 [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 doi: 10.1016/S0360-1285(00)00011-3 [6] Zhou H, Zhou M X, Liu Z H, et al. Modeling NOx emission of coke combustion in iron ore sintering process and its experimental validation. Fuel, 2016, 179: 322 doi: 10.1016/j.fuel.2016.03.098 [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 doi: 10.2355/isijinternational.32.1047 [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狀態の影響. 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 doi: 10.2355/isijinternational.ISIJINT-2015-089 [11] Arikata Y, Yamamoto K, Sassa Y. Effect of coke breeze addition timing on sintering operation. ISIJ Int, 2013, 53(9): 1523 doi: 10.2355/isijinternational.53.1523 [12] Oba Y, Konishi H, Ono H, et al. Combustion behavior of coated cokes with fine Fe3O4 and 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 doi: 10.1016/j.powtec.2016.05.043 [14] Gan M, Fan X H, Ji Z Y, et al. Effect of distribution of biomass fuel in granules on iron ore sintering and NOx emission. Ironmaking Steelmaking, 2014, 41(6): 430 doi: 10.1179/1743281213Y.0000000138 [15] Hou P, Choi S, Choi E, et al. Improved distribution of fuel particlesin iron ore sintering process. Ironmaking Steelmaking, 2011, 38(5): 379 doi: 10.1179/1743281211Y.0000000017 [16] Terushige N, Masanori N, Tetsuya N. Effect ofgranule structure on the combustion behavior of coke breeze//Proceedings of the 5th 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 doi: 10.2355/isijinternational.53.1594 [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狀態の異なるコークスの充填層內燃焼速度. 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 doi: 10.1016/j.combustflame.2014.09.026 [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 http://www.researchgate.net/publication/288555320_Combustion_Rate_and_NO_Emission_during_Combustion_of_Coke_Granules_in_Packed_Beds [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. 化學工學論文集, 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 doi: 10.2355/isijinternational.ISIJINT-2015-742 [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 doi: 10.1016/j.ijhydene.2016.07.187 -
點擊查看大圖
計量
- 文章訪問數: 1050
- HTML全文瀏覽量: 501
- PDF下載量: 24
- 被引次數: 0
