Author: Junying Wang (Xi'an Jiaotong University) - The sulfur compounds in coal release sulfur oxides during thermochemical conversion, which easily form acid rain when discharged into the air, causing environmental pollution and ecological damage. There is a significant need for the development of efficient and environmentally friendly desulfurization technology. To promote the clean and efficient utilization of coal resources, this work carried out an experimental study of desulfurization under the supercritical CO2-cosolvent system using Zhundong coal as the research object. The extraction effects on sulfur compounds in coal were systematically investigated by adding nine different kinds of cosolvents. Meanwhile, the sulfur content, pore structure, and functional group changes of the coal samples after extraction with different mixed solvents were analyzed using elemental analyzer, fully automatic specific surface area and porosity analyzer, and Fourier transform infrared spectrometer, respectively. The experimental results showed that the cosolvent could significantly enhance the extraction capacity of supercritical CO2 for sulfur in coal, and the desulfurization rate could reach up to 23.68%. Among them, the supercritical CO2-methanol solvent controlled the loss of coal sample quality while maintaining a higher desulfurization efficiency, showing a superior synergistic desulfurization performance. The specific surface area and pore volume of the coal samples did not change significantly after extraction. The results of infrared spectroscopy further verified that the supercritical fluid treatment did not destroy the aromatic ring conjugate bonding system of the coal samples. This study aims to provide an experimental basis for the development of efficient and green coal desulfurization technology and to promote the development of supercritical desulfurization technology.
