In order to be able to be used in refineries for the purpose of the production of fuel, pyrolysis oils have to undergo a pretreatment targeted at stabilizing them. Such a pretreatment can be a deoxygenation stage which can be:

total, in order to convert the bio-oils into fuel bases,

partial (>90%), in order to render the oils miscible with hydrocarbon fractions of petroleum origin, and thus to introduce it into the refining scheme,

partial (>50%), in order to stabilize the oils for the purpose of subsequent use.

This deoxygenation can be carried out in particular by hydrodeoxygenation (HDO), according to the simplified reaction:
C6H8O4+4H2→C6H8+4H2O

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