An overview of biochar production techniques and application in iron and steel industries

Abstract

Integrating innovation and environmental responsibility has become important in pursuing sustainable industrial practices in the contemporary world. These twin imperatives have stimulated research into developing methods that optimize industrial processes, enhancing efficiency and effectiveness while mitigating undesirable ecological impacts. This objective is exemplified by the emergence of biochar derived from the thermo-chemical transformation of biomass. This review examines biochar production methods and their potential applications across various aspects of the iron and steel industries (ISI). The technical, economic, and sustainable implications of integrating biochar into the ISI were explored. Slow pyrolysis and hydrothermal carbonization are the most efficient methods for higher biochar yield (25-90%). Biochar has several advantages- higher heating value (30-32 MJ/kg), more porosity (58.22%), and significantly larger surface area (113 m²/g) compared to coal and coke. However, the presence of biochar often reduces fluidity in a coal-biochar mixture. The findings highlighted that biochar production and implementation in ISI often come with higher costs, primarily due to the higher expense of substitute fuels compared to traditional fossil fuels. The economic viability and societal desirability of biochar are highly uncertain and vary significantly based on factors such as location, feedstock type, production scale, and biochar pricing, among others. Furthermore, biomass and biochar supply chain is another important factor which determines its large scale implementation. Despite these challenges, there are opportunities to reduce emissions from BF-BOF operations by utilizing biochar technologies. Overall, the present study explored integrating diverse biochar production methods into the ISI aiming to contribute to the ongoing research on sustainable manufacturing practices, underscoring their significance in shaping a more environmentally conscious future.

Keywords: Biochar; Biomass conversion; Carbon sequestration; Environmental responsibility; Iron and steel industries.

Fig. 1

Energy utilization and CO₂ emission in the industrial sector- (a) energy use, (b) CO₂ emission, (c) energy consumption by fuel type, (d) Energy utilization for all technology, and (e) CO₂ emission for all technology. Reprinted from Moglianesi et al. (2023) and Mousa et al. (2016) (Copyright © 2024, with permission from Elsevier)

Fig. 2

Different applications of biochar. Reprinted from Wang and Wang (2019) (Copyright © 2024, with permission from Elsevier)

Fig. 3

Biochar use in an integrated ISI. Reprinted from Meng et al. (2024) (Copyright © 2024, with permission from Elsevier)

Fig. 4

Biochar samples generated from (a) banana stalk, (b) rice husk, and (c) corncob. Adopted from Ibitoye et al. (2022) and modified (Open access without copyright permission requirement)

Fig. 5

Comparison of different biochar production techniques. The data extracted from Ercan et al. (2023) and was plotted with Origin 2021 (Copyright © 2024, with permission from Elsevier)

Fig. 6

Foaming characteristics and measurement. Adopted from Kieush and Schenk (2023) (Open access without copyright permission requirement)

Fig. 7

Effect of replacing coke breeze with biochar on the strength and volume of the resulting sinter. Reprinted from El-Hussiny et al. (2015) (Open access without copyright permission requirement)

Fig. 8

Effect of biochar utilization as a substitute to coke breeze on the performance of sintering machine and BF. Reprinted from El-Hussiny et al. (2015) (Open access without copyright permission requirement)

Fig. 9

Environmental implication of biochar utilization in an integrated steel-making process. The data was extracted from Mathieson et al. (2015) and was plotted with Microsoft Excel 2023 (Copyright © 2024, with permission from Elsevier)

Fig. 10

Raw material flow and greenhouse gas emissions in a typical ISI. Reprinted from Meng et al. (2024) (Copyright © 2024, with permission from Elsevier)

Fig. 11

Greenhouse gas emissions in the twelve biochar substitution situations in ISI: (a) GWP100 emissions and (b) Sankey chart. Reprinted from Meng et al. (2024) (Copyright © 2024, with permission from Elsevier)

Fig. 12

CO₂ supply curve (SCS) of the emission reduction technologies of ISI: (a) CSC with a discount rate of 10% and 20% and (b) CSC with biochar utilization. Reprinted from Meng et al. (2024) (Copyright © 2024, with permission from Elsevier)

Fig. 13

Reduction characteristics of biochar: (a) reduction mechanism and (b) reaction kinetics. Adopted from Kowitwarangkul et al. (2014) and Michishita and Tanaka (2010) (Open access without copyright permission requirement)

Fig. 14

A typical continuous pyrolysis plant. Reprinted from Doing (2024) (Copyright © 2024, with permission from Henan Doing Environmental Protection Technology Co., Ltd.)