Effect of red mud-based additives on the formation characteristics of tar and gas produced during coal pyrolysis. (October 2022)

• Record Type: Journal Article
• Authors: Wang, Guijin; Wang, Yiming; Lv, Jiannan; Wu, Yunfei; Jin, Lijun; Li, Yang; Yang, He; Hou, Baolin; Hu, Haoquan
• Is Part Of: Journal of the Energy Institute. Volume 104(2022)
• Page Start: 1
• Page End: 11
• Publication Date: 2022-10
• Subjects: Coal pyrolysis -- Red mud -- Tar -- Gas -- Aromatic hydrocarbons; Power (Mechanics) -- Periodicals; Power resources -- Periodicals; Fuel -- Periodicals; 621.04205
• DOI: 10.1016/j.joei.2022.06.009
• Languages: English
• ISSNs: 1743-9671

Abstract

Abstract: Red mud (RM), an industrial solid waste, was introduced into the coal pyrolysis reaction system, and its effect on the formation characteristics of tar and gas products during coal pyrolysis was explored based on the regulation and characterization of RM structure along with a series of fixed-bed pyrolysis experiments. The results show that Fe2 O3 in RM could react with reducing agents, e.g., solid carbon, H2 and CO, in coal pyrolysis environment, along with the gradual reduction process of Fe2 O3 →Fe3 O4 →FeO→Fe. As a result, coal conversion as well as release of light gas, such as CO and CO2, are both promoted. Influence tendency of RM after acid treatment (ARM) is consistent with that of the initial RM but the magnitude becomes greater. Compared with RM, ARM has a larger specific surface area and more developed mesoporous structure, thus providing a stronger regulation performance on tar composition. In the presence of ARM, contents of phenols, indenes and aliphatics in tar decrease, accompanied by the increase of monocyclic aromatic hydrocarbons, and the content of BTX and its yield increase by 76.25% and 47.90%, respectively. Furthermore, both the light components (boiling point, BP ≤ 360 °C) and light oil (BP ≤ 170 °C) in tar reach higher levels with addition of ARM. Therefore, ARM is an effective multifunctional catalyst for in-situ upgrading of tar during coal pyrolysis process. Graphical abstract: Image 1 Highlights: Acid treatment of red mud (ARM) can reconstruct its composition and pore structure. ARM exhibits enhanced effects on internal transformation of compounds in tar than RM. ARM is an effective multifunctional catalyst for promoting BTX generation. Harmless utilization of RM could be realized based on optimized coal pyrolysis process.