Abstract:

MoS₂ has been commonly used as an efficient catalyst for the kerogen hydropyrolysis to improve the yield with activated high-pressure and mobile phase of H₂. However， there is little document on whether MoS₂ has a certain effect on the thermal maturation of organic matter and hydrocarbon generation. In this study， the effects of MoS₂ on the thermal evolution of organic matter and hydrocarbon generation are investigated by comparative thermal simulation experiments on kerogen of low maturity from the Alum Shale with and without MoS₂ added. The results show that low-mature kerogen has greater potential for hydrocarbon generation in presence of MoS₂. MoS₂ acts to increase the peak yield of light hydrocarbons （C_6-14）， while decrease the peak yield of heavy hydrocarbons （C₁₄₊）， and lowering the temperature of peak hydrocarbon generation by about 24 ℃ at the same time， indicating that MoS₂ serves to accelerate the thermal cracking of heavy hydrocarbons to light hydrocarbons. The adding of MoS₂ also can slightly increase the yield of wet gases （C_2-5） before the peak hydrocarbon generation temperature （456 ℃） is reached， but significantly decrease it after the temperature surpasses its peak hydrocarbon generation value， indicating that MoS₂ can promote the generation and later cracking of wet gases. In addition， the existence of MoS₂ also remarkably raise the yield of methane （C₁）， especially at a temperature higher than 528 ℃ when the methane yield increases by nearly 50 %， a possible result of MoS₂ promoting the hydrogenation of kerogen at the high-to-over-mature stage. The difference of catalytic effect between pyrite （FeS₂） and MoS₂ is systematically compared， which is mainly controlled by the structure， stability and sulfur activity of catalysts.

Key words: MoS₂ catalyst, hydrogenation, catalytic effect, sulfur, thermal simulation, kerogen, hydrocarbon generation potentia