Thermogenic gases generated from coals and shales of the Upper Silesian and Lublin basins: hydrous pyrolysis approach

Abstract

In order to provide a better characterization of the origin and volume of thermogenic gas generation hydrous pyrolysis (HP) experiments were performed on coals and shales at 330 and 360^oC for 72 hours. The maturity range of coals and shales used for HP varies from 0.57 to 0.92% R_o. The maturity increase caused by HP at 330 and 360^oC ranges from 1.32 to 1.39% and from 1.71 to 1.83%, respectively. δ¹³C of CH₄, C₂H₆, C₃H₆ and n-C₄H₁₀ in HP gases versus their reciprocal C-number have a concave relationship, and therefore do not follow a linear trend. δ²H of CH₄, C₂H₆ and C₃H₆ in HP gases versus their reciprocal H-number show both linear and convex-concave relationships. The growth of CO₂ yields during HP was higher for shales than for coals. H₂S yields from shales are higher than from coals, which can be connected with catalytic and adsorbed influence of shale matrix. H₂ was also generated in notable quantities from water and organic matter of coals and bigger amounts from shales. N₂ yields grow with the increase of R_o after 360^oC HP and it is more enriched in ¹⁵N isotope than after 330^oC.