Reaction Behavior of Biochar Composite Briquette Under H<sub>2</sub>-N<sub>2</sub> Atmosphere: Experimental Study
Charging biochar composite briquettes (BCBs) and the injection of hydrogen-rich gas into the blast furnace (BF) are two efficient methods for reducing CO<sub>2</sub> emission in BF ironmaking. This study investigated the reaction behavior of BCBs under a hydrogen-rich atmosphere to explo...
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MDPI AG
2025-02-01
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| author | Ting Zhang Yan Liu Huiqing Tang |
| author_facet | Ting Zhang Yan Liu Huiqing Tang |
| author_sort | Ting Zhang |
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| description | Charging biochar composite briquettes (BCBs) and the injection of hydrogen-rich gas into the blast furnace (BF) are two efficient methods for reducing CO<sub>2</sub> emission in BF ironmaking. This study investigated the reaction behavior of BCBs under a hydrogen-rich atmosphere to explore the potential combination of these two methods for enhanced CO<sub>2</sub> emission reduction efficiency in the BF. The employed BCB had a chemical composition of 52.57 wt.% Fe<sub>3</sub>O<sub>4</sub>, 24.54 wt.% FeO, 0.98 wt.% Fe, 13.16 wt.% C, and 8.75 wt.% gangue. Isothermal BCB reaction tests were conducted using a custom-design thermogravimetric device under temperatures ranging from 1173 K to 1373 K and under an atmosphere of N<sub>2</sub>-H<sub>2</sub> with a H<sub>2</sub> content from 25 vol.% to 75 vol.%. A mathematical model was developed for the kinetics of the BCB reaction behavior under the H<sub>2</sub>-N<sub>2</sub> atmosphere. Results showed that the developed model was adequate in predicting the reaction behavior of BCB. Under an atmosphere of 50 vol.% H<sub>2</sub>-N<sub>2</sub>, increasing the temperature from 1173 K to 1373 K resulted in a decrease in the fraction of iron-oxide oxygen removed by hydrogen from 62% to 26% and an increase in the fraction removed by biochar from 29% to 72%, indicating that hydrogen is the primary reducing agent under low temperatures, whereas, under high temperatures, biochar plays a more significant role. Under a constant temperature of 1273 K, increasing the H<sub>2</sub> content in the atmosphere from 25 vol.% to 75 vol.% led to an increase in the fraction of iron-oxide oxygen removed by hydrogen from 37% to 45%, and a decrease in the fraction removed by biochar from 57% to 53%, suggesting that a higher H<sub>2</sub> content enhances the iron oxide reduction by hydrogen but has little impact on the reduction by biochar. In the reaction process, the main products were CO and H<sub>2</sub>O, the iron oxide reduction occurred more rapidly near the center than near the surface, whereas the gasification of biochar followed the opposite trend. The structural transformation of the BCB progressed from sinter iron oxides into the metallic iron network in the reaction. |
| format | Article |
| id | doaj-art-e2dfc37460ec4ebf9711da4ba8121da5 |
| institution | DOAJ |
| issn | 2075-4701 |
| language | English |
| publishDate | 2025-02-01 |
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| spelling | doaj-art-e2dfc37460ec4ebf9711da4ba8121da52025-08-20T02:42:22ZengMDPI AGMetals2075-47012025-02-0115323610.3390/met15030236Reaction Behavior of Biochar Composite Briquette Under H<sub>2</sub>-N<sub>2</sub> Atmosphere: Experimental StudyTing Zhang0Yan Liu1Huiqing Tang2State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, ChinaState Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, ChinaState Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, ChinaCharging biochar composite briquettes (BCBs) and the injection of hydrogen-rich gas into the blast furnace (BF) are two efficient methods for reducing CO<sub>2</sub> emission in BF ironmaking. This study investigated the reaction behavior of BCBs under a hydrogen-rich atmosphere to explore the potential combination of these two methods for enhanced CO<sub>2</sub> emission reduction efficiency in the BF. The employed BCB had a chemical composition of 52.57 wt.% Fe<sub>3</sub>O<sub>4</sub>, 24.54 wt.% FeO, 0.98 wt.% Fe, 13.16 wt.% C, and 8.75 wt.% gangue. Isothermal BCB reaction tests were conducted using a custom-design thermogravimetric device under temperatures ranging from 1173 K to 1373 K and under an atmosphere of N<sub>2</sub>-H<sub>2</sub> with a H<sub>2</sub> content from 25 vol.% to 75 vol.%. A mathematical model was developed for the kinetics of the BCB reaction behavior under the H<sub>2</sub>-N<sub>2</sub> atmosphere. Results showed that the developed model was adequate in predicting the reaction behavior of BCB. Under an atmosphere of 50 vol.% H<sub>2</sub>-N<sub>2</sub>, increasing the temperature from 1173 K to 1373 K resulted in a decrease in the fraction of iron-oxide oxygen removed by hydrogen from 62% to 26% and an increase in the fraction removed by biochar from 29% to 72%, indicating that hydrogen is the primary reducing agent under low temperatures, whereas, under high temperatures, biochar plays a more significant role. Under a constant temperature of 1273 K, increasing the H<sub>2</sub> content in the atmosphere from 25 vol.% to 75 vol.% led to an increase in the fraction of iron-oxide oxygen removed by hydrogen from 37% to 45%, and a decrease in the fraction removed by biochar from 57% to 53%, suggesting that a higher H<sub>2</sub> content enhances the iron oxide reduction by hydrogen but has little impact on the reduction by biochar. In the reaction process, the main products were CO and H<sub>2</sub>O, the iron oxide reduction occurred more rapidly near the center than near the surface, whereas the gasification of biochar followed the opposite trend. The structural transformation of the BCB progressed from sinter iron oxides into the metallic iron network in the reaction.https://www.mdpi.com/2075-4701/15/3/236biochar composite briquettereaction behaviorN<sub>2</sub>-H<sub>2</sub> atmosphere |
| spellingShingle | Ting Zhang Yan Liu Huiqing Tang Reaction Behavior of Biochar Composite Briquette Under H<sub>2</sub>-N<sub>2</sub> Atmosphere: Experimental Study Metals biochar composite briquette reaction behavior N<sub>2</sub>-H<sub>2</sub> atmosphere |
| title | Reaction Behavior of Biochar Composite Briquette Under H<sub>2</sub>-N<sub>2</sub> Atmosphere: Experimental Study |
| title_full | Reaction Behavior of Biochar Composite Briquette Under H<sub>2</sub>-N<sub>2</sub> Atmosphere: Experimental Study |
| title_fullStr | Reaction Behavior of Biochar Composite Briquette Under H<sub>2</sub>-N<sub>2</sub> Atmosphere: Experimental Study |
| title_full_unstemmed | Reaction Behavior of Biochar Composite Briquette Under H<sub>2</sub>-N<sub>2</sub> Atmosphere: Experimental Study |
| title_short | Reaction Behavior of Biochar Composite Briquette Under H<sub>2</sub>-N<sub>2</sub> Atmosphere: Experimental Study |
| title_sort | reaction behavior of biochar composite briquette under h sub 2 sub n sub 2 sub atmosphere experimental study |
| topic | biochar composite briquette reaction behavior N<sub>2</sub>-H<sub>2</sub> atmosphere |
| url | https://www.mdpi.com/2075-4701/15/3/236 |
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