Shale samples from well cores from Christian County, Kentucky, and Effingham, Henderson, and Tazewell Counties, Illinois, were studied for the noncondensable (at room temperature) hydrocarbon gases produced during pyrolysis. The data show a direct correlation of the total hydrocarbon gas (C1 to C5) yield from the shale pyrolyzed at 600°C to the organic carbon content of the shale and relations of the gas released from specially “canned” core sections at room temperature to the organic carbon content and to the total porosity of the shale.
The composition of the noncondensable hydrocarbon gases was studied on selected black-shale samples with stepwise increases in temperature. The formation of alkanes is favored over alkenes at low temperature. Alkenes, C1, and C2 species from thermal cracking are positively identified when the shale has been heated to above 120°C, if other conditions remain constant.
The effect of the pyrolysis atmosphere on the yield of light hydrocarbons (C1 to C8), acetaldehyde, acetone, carbon monoxide, and carbon dioxide during thermal degradation of selected gram-sized black-shale samples was studied also. The effects of varying the amount of oxygen in the pyrolysis atmosphere have been monitored. The yield of an individual hydrocarbon generally increases until the oxygen content of the pyrolysis atmosphere reaches 10%. Above 10% oxygen there is a slight decrease in yield. The yield of carbon monoxide and carbon dioxide increases directly with the increase of oxygen content of the pyrolysis atmosphere.
Data derived from this study may improve our understanding of the potential for gas production and the prediction of gas production from the eastern black shale. It may also provide information useful for controlling the quality of the gas produced by shale pyrolysis.