Effects of Coal Desulfurization on Ultimate, Proximate, Calorific Value and Functional Group Transformations

¹ Faculty of Applied Sciences, Universiti Teknologi Mara, Arau Campus, 02600 Perlis, Malaysia.
² Faculty of Chemical Engineering, Universiti Teknologi Mara, Shah Alam Campus, 40450 Selangor, Malaysia.
³ Faculty of Civil Engineering Technology, Universiti Malaysia Perlis (UniMAP), 02600 Arau, Perlis, Malaysia.
⁴ Coal and Biomass Energy Research Group, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor, Malaysia.

^* Corresponding author: syarifah_nursyimi@uitm.edu.my

Abstract

Coal desulfurization is essential for addressing environmental concerns about air quality, human health, and climate change. In this study, coal treated with potassium carbonate (PC)-ethylene glycol (EG) at a molar ratio of 1:8 for 60 minutes at 30 °C achieved a 40.24 % reduction in sulfur content. The ultimate analysis revealed reductions in carbon, hydrogen, and nitrogen content but an increase in oxygen concentration. The proximate analysis showed a significant decrease in the volatile matter, indicating the transformation of the coal’s aromatic and long-chain hydrocarbons into shorter-chain hydrocarbons. Additionally, the treatment increased the fixed carbon content, suggesting better heat generation during combustion and improved coal quality. Although the proximate analysis has implications for calorific value, the decrease in calorific value for the treated coal was mainly due to the reduction in sulfur content. The Fourier Transform Infrared Spectroscopy (FTIR) detected changes in peak positions for aromatic C=C, thiophene, and organic sulfates. The peaks for thiophene and organic sulfates showed a shift to higher wavenumbers, indicating that the PC: EG mixture effectively removed sulfur from coal. This study demonstrates a promising approach towards meeting the safety and environmental targets outlined in the 2030 Agenda for Sustainable Development.