基于優化粗粒級固體燃料賦存形態的鐵礦燒結過程NOx減排

闕志剛; 吳勝利; 艾仙斌

doi:10.13374/j.issn2095-9389.2019.02.21.001

基于優化粗粒級固體燃料賦存形態的鐵礦燒結過程NO_x減排

doi: 10.13374/j.issn2095-9389.2019.02.21.001

闕志剛^{1, 2,},
吳勝利^1, ,,
艾仙斌²

1.
北京科技大學冶金與生態學院，北京 100083
2.
江西省科學院能源研究所，南昌 330096

基金項目: 國家自然科學基金資助項目（5190040957）；江西省自然科學基金資助項目（20192BAB216018）；江西省科學院博士資助項目（2018-YYB-05）；普惠制一類資助項目（2018-XTPH1-05）

詳細信息

通訊作者:
E-mail: wushengli@ustb.edu.cn

中圖分類號: TF046.4
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出版歷程
- 收稿日期: 2019-02-21
- 刊出日期: 2020-02-01

To reduce NO_x emission based on optimizing the existing states of coarse coke breeze during iron ore sintering process

QUE Zhi-gang^{1, 2
,},
WU Sheng-li^{1
, ,},
AI Xian-bin²

1.
School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
2.
Institute of Energy Research, Jiangxi Academy of Science, Nanchang 330096, China

More Information

Corresponding author: E-mail: wushengli@ustb.edu.cn

摘要

摘要: 鐵礦燒結工序作為鋼鐵行業NO_x排放的主要來源，在當前高壓環保態勢下減少其NO_x排放迫在眉睫。燒結過程NO_x主要產生于固體燃料燃燒過程，而粗粒級燃料的賦存形態會影響其NO_x排放。基于此，本研究采用可視化微型燒結燃燒裝置研究裸露型和被覆型粗粒級焦粉的燃燒行為，以及優化其配加模式對NO_x排放和燒結固結強度的影響規律，并燒結杯實驗研究兼顧NO_x減排和燒結產質量指標的適宜粗粒級燃料賦存形態。結果表明，相比裸露型粗粒級焦粉，表面被覆鐵酸鈣細粉時其NO_x排放降低約56%；分加粗粒級焦粉以調控其為裸露型時，NO_x排放增加約10%，且燒結礦強度降低，而控制粒度為0.5～3.15 mm以調控其為被覆型時，NO_x最大體積分數和N元素轉化率分別降低約8%和27%，且燒結各項產質量指標均得到改善。
- 鐵礦燒結 /
- NO_x /
- 固體燃料 /
- 賦存形態 /
- 燃燒行為 /
- 配加模式
Abstract: With the development of the iron and steel industry, the amount of NO_x emissions is increasing year by year, and this causes environmental pollution in forms such as acidic rain and photochemical smog, which greatly threatens human health and social development. The iron and steel industry is one of the major sources of NO_x emissions, accounting for more than 10% of the total NO_x emissions, and the iron ore sintering process is one of the major sources of NO_x emissions in the iron and steel industry, as it accounts for more than 50% of the total emissions of iron and steel plants. Hence, it is extremely urgent to reduce NO_x emissions under the current high requirements of environmental protection. Since sintering gas is characterized by large volume, high dust and oxygen content, low NO_x concentration, and the presence of SO₂, available technologies used in De-NO_x have the disadvantages of low efficiency and high investment and cost. Presently, how to cost-effectively reduce the NO_x emission of the iron ore sintering process is a new challenge in the iron and steel industry. In the sintering process, NO_x is mainly generated in the combustion of solid fuels, which is affected by the existing states of coarse solid fuels. Hence, the combustion behaviors of uncovered and coated coarse coke breeze and the effects of their addition methods on the NO_x emission and the bonding strength of the sinter were investigated by the visible micro sintering and combustion equipment. Then, the optimal existing state of coarse coke breeze was explored by sinter pot tests. The results show that compared with the uncovered coarse coke breeze, the NO_x emission decreases by 56% when coarse coke breeze is coated with calcium ferrite fines. As the coarse coke breeze is separated and controlled to be in an uncovered state, then it is added into the sintering materials after first mixing process, NO_x emission increases by about 56% and the strength of the sinter decreases. The maximum concentration of NO_x and conversion rate of N element decrease by 8% and 27%, respectively, when the coke breeze is a coated state by controlling in the size of 0.50?3.15 mm, respectively. The sinter indexes are also improved.
- iron ore sinter /
- NO_x /
- solid fuel /
- existing state /
- combustion behavior /
- adding method

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圖 1 可視化微型燒結燃燒裝置

Figure 1. Schematic diagram of the visible micro sintering and combustion equipment

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圖 2 燃燒實驗中準顆粒試樣

Figure 2. Quasi-particles samples of combustion test

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圖 3 燃燒實驗的溫度制度和氣氛

Figure 3. Temperature system and atmosphere of combustion test

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圖 4 不同賦存形態粗粒級焦粉的燃燒行為

Figure 4. Combustion behavior of different existing states of coarse coke breeze

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圖 5 不同賦存形態粗粒級焦粉燃燒過程其NO排放規律

Figure 5. NO emission during the combustion of coarse coke breeze in different existing states

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圖 6 不同賦存形態粗粒級焦粉的燃燒速率變化規律

Figure 6. Combustion rates of coarse coke breeze in different existing states

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圖 7 不同賦存形態粗粒級焦粉的燃燒速率與NO體積分數間的關系。（a）Al₂O₃；（b） CF

Figure 7. Relationship between combustion rates and NO volume fraction of different existing states of coarse coke breeze: (a) Al₂O₃; (b) CF

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圖 8 不同賦存形態粗粒級焦粉燃燒過程其CO排放及其與N元素轉化率間的關系。（a） CO排放規律；（b） CO排放總量與N元素轉化率間的關系

Figure 8. CO emission and correlativity of emission total of CO with conversion rate of N element during the combustion of coarse coke breeze in different existing states: (a) CO emission; (b) relation of emission total of CO and conversion rate of N element

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圖 9 不同焦粉粗顆粒配加模式下N元素轉化率和燒結固結強度的變化規律。（a） N元素轉化率；（b）固結強度

Figure 9. Conversion rate of N element and strength of sinter in different adding methods of coarse coke breeze: (a) conversion rate of N element; (b) strength of sinter

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表 1 焦粉的化學成分、熱值及著火溫度

Table 1. Chemical composition, low calorific value, and ignition temperature of coke breeze

燃料種類	工業分析（質量分數）/%				元素分析（質量分數）/%			著火溫度/℃	低位熱值/ (kJ·kg^?1)
燃料種類	固定碳	揮發分	灰分	工業水分	C	H	N	著火溫度/℃	低位熱值/ (kJ·kg^?1)
焦粉	82.19	1.25	12.63	3.93	85.55	0.11	0.97	562.8	29313

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表 2 焦粉的粒度組成

Table 2. Size distribution of coke breeze

燃料種類	各粒級所占質量分數/%								平均粒徑/mm
燃料種類	>5.0 mm	3.15～5.0 mm	2～3.15 mm	1.0～2.0 mm	0.5～1.0 mm	0.25～0.5 mm	0.15～0.25 mm	<0.15 mm	平均粒徑/mm
焦粉	2.60	9.70	8.40	16.6	31.4	15.20	11.40	4.70	1.48

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表 3 燒結混合料中各物料配比（質量分數）

Table 3. Proportions of raw materials in sinter mixture %

物料	混勻礦	生石灰	石灰石	白云石	蛇紋石	返礦	焦粉	合計
配比	61.43	3.50	1.37	4.43	0.28	25.00	4.00	100.00

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表 4 燒結混合料中各物料的粒度組成（質量分數）

Table 4. Size composition of raw materials in sinter mixture %

物料	>10 mm	8～10 mm	5～8 mm	3～5 mm	2～3 mm	1～2 mm	0.5～1 mm	0.25～0.5 mm	0.15～0.25 mm	<0.15 mm
混勻礦	4.28	4.41	11.24	11.99	9.96	15.67	12.41	9.83	8.10	12.75
生石灰	0	0	0	0.14	1.33	4.15	6.00	12.28	14.24	61.87
石灰石	0	0	0.13	8.99	11.89	19.67	19.89	8.53	5.14	25.74
白云石	0	0	0	3.11	13.96	21.83	18.77	11.13	10.37	20.84
蛇紋石	0	0	0	5.50	14.50	28.45	20.45	12.10	8.35	10.65
返礦	0.49	0.97	20.54	47.61	11.83	9.10	4.79	2.25	2.43	0

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表 5 燒結杯實驗結果

Table 5. Results of sinter pot tests

方案	NO_x排放指標		燒結產質量指標
方案	NO_x最大體積分數/ 10^?2	噸礦NO_x排放/ （kg·t^?1）	垂直燒結速度/ （mm·min^?1）	成品率/ %	燒結利用系數/ （t?m^?2?h^?1）	轉鼓強度_{+6.3 mm}/ %
全粒級焦粉	164	0.62	26.81	80.36	2.00	60.00
>0.5 mm焦粉分加	167	0.66	27.14	79.12	2.12	60.67
0.5~3.15 mm焦粉	151	0.45	28.47	80.59	2.18	60.67

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