The synergistic mechanism on microwave and MoS2 in coal pyrolysis

Abstract

Microwave pyrolysis has been widely studied as a new type of coal thermal processing. In this research, we applied different amounts of MoS2 to the coal microwave pyrolysis and observed the consequent product effects to see if a higher pyrolysis efficiency and tar quality can be achieved. The catalytic action of MoS2 in solid, liquid, and gas products was further studied using both conventional and microwave pyrolysis, and a synergistic mechanism of microwave and MoS2 for coal pyrolysis was proposed. In a self-developed coal-gas microwave co-pyrolysis system, Proximate and ultimate analysis methods, X-ray diffraction, Scanning electron microscopy, Energy dispersive spectrometry, Fourier transform infrared spectroscopy, Gas chromatography–mass spectrometry and Gas analyzer were all employed to test and analyze pyrolysis products. The experimental results showed that when the amount of MoS2 was 8.3%, in microwave pyrolysis, the yield of liquid product was 28.4% with the light oil yield of 67.55%, and the yield of hydrogen was 22.19%. Compared with conventional pyrolysis, conventional pyrolysis with 8.3%MoS2 and microwave pyrolysis, a tighter structure of solid product, a higher yield of liquid product with an obvious light oil content increase could be obtained. The content of hydrogen in gas product decreased, while the valuable content of gas (CH4+CO+H2) and calorific value increased. The contrast experiments of coal pyrolysis showed that there was a synergetic effect of microwave and MoS2, and it improved the coal pyrolysis efficiency and tar quality.