Microwave pyrolysis of rapeseed straw for low sulfur content and high heating value (HHV) solid fuel production: transformation mechanism and form of sulfur in biochar during the pyrolysis process

Manqing Li, Ying Li, Chunyang Lu, Taida Wei, Masood Ahmed, Dejin Qiu, Yuandong Xiong, Jie Ren and Yaowei Yu

Energy, 2025, vol. 326, issue C

Abstract: Clarifying the transformation behavior of sulfur in biomass pyrolysis is essential for achieving biochar resource utilization. Renewable biochar can replace traditional fossil fuels and be applied in industry to achieve sustainable development. This study employed microwave pyrolysis to prepare a low sulfur and high heating value (HHV) rapeseed straw biochar. 84.6 % of sulfur in the biochar was removed, and its HHV as high as 27.33 Mj/kg, which is similar to anthracite. The effects of pyrolysis temperature and residence time on sulfur's transformation mechanism and form were investigated. Results showed that 61 % of sulfur was evaporated into the gas, 23.6 % was transferred to the bio-oil, and 15.4 % of sulfur was retained in the biochar in organic and inorganic forms at 550 °C. The inorganic sulfur in biochar will combine with K and Na to form K3Na(SO4)2 sulfate. During microwave pyrolysis, most organic sulfur reaction with H, O, and C atoms in the biochar to form sulfur-containing gas (H2S, SO2, COS, C2H6S2, C2H6S, and CH3SH). These results highlight the potential of microwave treatment as an efficient method for purifying rapeseed straw into a low sulfur, high heating value, and environmentally friendly solid energy.

Keywords: Microwave pyrolysis; Rapeseed straw; Biochar; Desulfurization rate; Sulfur speciation; Solid energy (search for similar items in EconPapers)
Date: 2025
References: Add references at CitEc
Citations:

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0360544225020237
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:326:y:2025:i:c:s0360544225020237

DOI: 10.1016/j.energy.2025.136381

Access Statistics for this article

Energy is currently edited by Henrik Lund and Mark J. Kaiser

More articles in Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().