Influence of inherent mineral matrix on the product yield and characterization from Huadian oil shale pyrolysis

• Published in: Journal of analytical and applied pyrolysis Vol. 130; pp. 269 - 276
• Main Authors: Chang, Zhibing, Chu, Mo, Zhang, Chao, Bai, Shuxia, Lin, Hao, Ma, Liangbo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2018
• Subjects: Carbonate minerals; Oil shale; Pyrolysis; Shale oil; Silicate minerals; Pyrolysis; Carbonate minerals; Oil shale; Silicate minerals; Shale oil
• ISSN: 0165-2370; 1873-250X
• DOI: 10.1016/j.jaap.2017.12.022

•Carbonates increase while silicates decrease the shale oil yield.•Carbonates facilitate while silicates suppress the formation of oxygenated compounds.•Silicates catalyze while carbonates inhibit the cracking of aliphatic hydrocarbons.•Silicates catalyze the aromatization of aliphatic hydrocarbons. Huadian oil shale was subjected to step-wise acid treatment to remove inherent carbonate and silicate minerals. The original oil shale and its demineralization products (carbonate- and carbonate-silicate-free oil shale samples) were pyrolyzed in a fixed-bed pyrolyzer to determine the mineral matrix effect on product yield and characteristics of shale oil and gases. The shale oil yields of original, carbonate-free, and carbonate-silicate-free oil shale samples were 50.4 wt.%, 44.3 wt.%, and 50.3 wt.% (values on dry and mineral matter-free basis), respectively, which indicated that carbonates promote, while silicates suppress, shale oil production. Coking of aromatic compounds appeared to be the dominant mechanism accounting for the variation of the shale oil yield. Elimination of the carbonate minerals decreased the nitrogen- and oxygen-containing compounds of shale oil, while removal of silicates increased the oxygenated compounds. Both carbonate and silicate minerals decreased the atomic H/C ratio of shale oil. Silicates promoted the cracking and aromatization of aliphatic hydrocarbons, which increased the short-chain aliphatic hydrocarbons and aromatic hydrocarbons of shale oil, as well as C1–C4 hydrocarbons and H2 yields. On the contrary, carbonates suppressed the cracking of long chain aliphatic hydrocarbons.