Molecular composition of low temperature coal tar and its transformation in the hydrogenation-refining process

Abstract

The low temperature coal tar is a complex mixture which poses a challenge to chemists for the molecular characterization. The State Key Laboratory of Heavy Oil Processing in the China University of petroleum-Beijing carried out in-deep analysis of the low temperature coal tar based on advanced technologies such as high resolution mass spectrometry. This review introduces the progress in molecular composition of low temperature coal tar. Bulk properties and molecular composition were characterized for ten coal tars derived from different low rank coals by gasification or carbonization. Distillation, extraction, and chromatographic methods were developed for the separation for various coal tar fractions. The raw coal tars, their fractions and hydrogenation-refining products were analyzed by gas chromatography-mass spectrometry (GC-MS) and high resolution mass spectrometry. Transformation of various compounds, especially for the heteroatoms was investigated in molecular level along the hydrogenation-refining process. In deep understanding of molecular composition and the transformation mechanism of coal tar will provide theory and data foundation for the utilization of low temperature coal tar, including the technology selection, catalyst design, process development and optimization.