Evolution mechanism of oxygen functional groups during pyrolysis of Datong coal

Abstract

The chemical structure and evolution mechanism of organic oxygen functional groups in Datong coal during pyrolysis were investigated in this paper. Firstly, qualitative and quantitative analyses to groups in Datong coal were achieved by Fourier transform infrared spectrometer. The results indicate that oxygen functional groups in this coal include hydroxyl, carboxyl, carbonyl group, and ether. Higher levels of oxygen functional groups and aromatic structures as well as low content of fat structure were found in Datong coal by peak fitting. Secondly, the main chemical reactions and effects during the pyrolysis of coal are described. Then, the evolution of the chemical structure and transformation mechanism of oxygen functional groups in Datong coal were represented and analyzed by wet chemical analysis. The analysis reveals that aromatic structures were heated and decomposed, oxygen was adsorbed, and then the phenolic hydroxyl groups were formed. When the temperature reaches 300 °C or higher, aromatic rings in phenolic hydroxyl were cracked and the carboxyl group was generated. The main purpose of this paper is to study the influence of temperature on the group types and their content in coal, and further to explain the evolution mechanism of the oxygen functional groups in the process of coal pyrolysis.