Waste cooking oil is a very good catalyst along others. You may wish to go through the profile of a colleague which has done some researches on the subject matter. Search for Yahya Muhammad Sani on research gate

Thanks Kaisan Muhammad Usman. Waste cooking oil is rather a raw material (not a catalyst) in the production of Biodiesel. I saw Yahya Muhammad Sani's work and it is on Biodiesel which is very different from bio-oil.

The hydrodeoxygenation of bio-oil requires use of a strong reductant such as H2. The cost of the hydrodeoxygenated fuel might be prohibitively high

Thanks Yurii V Geletii. As you mentioned the cost of hydrogen has a significant impact on economics. However, unless bio-oil is upgraded at a competitive cost, it will not be able to offer a future alternative.

Hypothetically, natural gas (CH4) can be used in pyrolysis of biomass to produce an upgraded bio-oil.

Heterogeneous catalysts are very effective for bio-oil upgrading. For expamle, solid acids such as zeolites (HZSM-5 etc.) and FCC; mesostructured MCM-41 are very useful in terms of activity and stability.

Thanks Tufan Salan. I will try to explore mesostructured MCM-41.

What are the chemical reactions leading to bio-oil upgrading?

Dear Dr. Yurii V Geletii,

Several and complex reactions take place during catalytic upgrading of bio-oil due to its structure having over 400 types of chemical compounds. Basically, cracking, decarbonylation, decarboxylation, hydrocracking, hydrodeoxygenation, hydrogenation, and polymerization are the most frequent reactions leading the upgrading process. However, the occurrence of these reactions varies according to catalyst type and process parameters.

I asked this question because a catalyst does not change the reaction thermodynamics. Therefore, there is no answer for the original question. It depends which reaction you want to catalyze. Decarbonylation and decarboxylation are thermodynamically favorable at high temperature. Hydrodeoxygenation can proceed only in the presence of H2 (or hypothetically CH4). Therefore, you need to know what is in your bio-oil and choose the reaction which can upgrade your fuel. Then, look for the catalyst of this reaction.

To my understanding, the main problem with bio-oil is the high oxygen content. Hydrodeoxygenation is the main reaction of interest in addition to others. It is true that the catalyst does not change the reaction thermodynamics however the selectivity is affected. As you know the most important criteria for selection of the catalyst are the activity, selectivity and stability. A cheaper more robust option will allow the reaction to be conducted in better conditions with a direct decrease in the price of utilities, equipment and thus a lower overall cost of production.

For the hydrodeoxygenation process, conventional catalysts such as Ni-Mo/Al2O3 and Co-Mo/Al2O3, which are used for the hydrodesulfurization of petroleum oil, along with noble-metal catalysts such as Ru/C, Pt/C, Pd/Co can be used. Moreover, bimetallic catalysts such as Pt-Fe/C, Pt-Cu/SiO2, Ni-Fe/Al2O3, Ni-Co/HZSM-5 can also be used. Nonetheless, catalyst deactivation is a serious problem owing to coke deposition and metal leaching along with the cost of the precious metal catalysts (e.g. platinum, ruthenium, rhodium).

Esterification with catalyst via combined reactive distillation can leaad products thst can by hyroprocessed easily too final products via convencional comercial hydrocracking catalyst can be better route low cost

Thanks Pagandai !!!

The effective catalysis for this process is zeolite due to its function as low cost, acidic catalysis and easily removed at the end of the reaction.