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

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.

Automated summary

The catalytic effect of several additives on the co-pyrolysis of Huadian oil shale and microalgal powder was investigated. CaO and Al2O3 showed significant potential for reducing the oxygen content of the oil and improving its quality. CaO facilitated dehydrogenation and alkene formation, while Al2O3 increased the H/C ratio and improved oil quality. ZSM-5 had negligible catalytic performance for deoxygenation. Al2O3 was selected as the most suitable additive for the co-pyrolysis process.