Deformation and Pore Structure Characteristics of Lignite Pyrolysis with Temperature Under Triaxial Stress
Year: 2025
Type: article
Abstract: As people pay increasing attention to the clean and efficient mining and utilization of coal resources, efforts to improve the utilization rate of coal, modify coal resources, and carry out coal gasification have become more and more important. The deformation characteristics of lignite, the most appropriate coal type for underground coal gasification, are intricately linked to its mechanical properties, permeability characteristics, and mining efficiency throughout the extraction process. The deformation and pore structure characteristics of lignite from room temperature to 650 °C have been studied through high-temperature triaxial penetration testing systems, NMR, and X-CT. As the temperature increases, the porosity of lignite rises, its mechanical strength decreases, and significant deformation occurs, and high temperatures promote pore development in lignite. The axial deformation of lignite pyrolysis is divided into three stages: the dehydration and degassing at room temperature to ~200 °C, the slow deformation between 200 °C and 300 °C, and the pyrolysis deformation from 300 °C to 650 °C. Significant deformation occurs during both the dehydration degassing and pyrolysis deformation stages. Between 250 °C and 650 °C, a large number of highly interconnected pore networks form. Investigating the deformation and pore structure characteristics of lignite is crucial for elucidating its mechanical and permeability features under varying temperature and pressure conditions.
Source: Processes
DOI: 10.3390/pr13051444
Authors: Feng Zhang, Shiwei Niu, Jiawei He, Kai Zhang, Zhongcheng Qin
Institution: Shandong University of Science and Technology
Language: English
Subfield: Ocean Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,896
OpenAlex ID: W4410242680