Non-catalytic and In-situ catalytic co-pyrolysis of Huadian oil shale and microalgae using several additives as catalyst

• Published in: Journal of analytical and applied pyrolysis Vol. 172; p. 106012
• Main Authors: Chang, Zhibing, Wang, Xinhong, Hao, Chengliang, Kuang, Wenhao, Wang, Chuchu, Zhou, Lingmei, Chu, Mo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2023
• Subjects: Catalytic deoxygenation; Co-pyrolysis; Microalgae; Oil shale; Pyrolytic oil; Microalgae; Co-pyrolysis; Catalytic deoxygenation; Oil shale; Pyrolytic oil
• ISSN: 0165-2370; 1873-250X
• DOI: 10.1016/j.jaap.2023.106012

The non-catalytic and in-situ catalytic co-pyrolysis of Huadian oil shale (OS) and microalgal powder (MP) were performed using a modified aluminum retort. By comparing the product yields and compositions for non-catalytic and catalytic pyrolyses, the catalytic effect of several additives, including MgO, CaO, ZrO2, Al2O3, zeolite Y, and zeolite ZSM-5, was investigated. This study focused on the deoxygenation performance of the pyrolytic oil. The oil yield increased with increasing MP addition in non-catalytic co-pyrolysis trials. At the OS/MP blending ratio of 3/1, the oil yield was 12.42 wt %, and the oxygen content and H/C ratio of oil were 11.54 wt % and 1.571, respectively. Both CaO and Al2O3 significantly decreased the oxygen content of the oil to <7 wt % with less oil loss (<1 wt %). CaO catalysis facilitated the dehydrogenation of free radicals to release H2, thereby increasing alkene formation and decreasing the H/C ratio of the oil to 1.441. Al2O3 catalysis increased the H/C ratio to 1.656 and improved the oil quality. ZSM-5 preferentially catalyzed the reaction between n-alkenes and nitrogenates to yield nitriles, and the catalytic performance for deoxygenation was negligible. Hence, Al2O3 was selected as the most suitable additive for the co-pyrolysis of OS and MP. •CaO and Al2O3 decrease the oxygen content of the oil with less oil loss.•CaO facilitates the dehydrogenation of free radicals to release H2.•Al2O3 increases the H/C ratio of the oil and improved the oil quality.•ZSM-5 catalyzes the reaction between n-alkenes and nitrogenates to yield nitriles.