For pyrolysis oil already some refinery schemes have been proposed that include reforming. Pyrolysis oil can in principle be steam-reformed directly via gas phase reforming (pressure 1-30 bar) in a stand alone application. However, more integrated process schemes would allow synergy and more favorable economics for both gas phase and high-pressure (liquid or supercritical) reforming. Three examples are briefly discussed below.

Co-reforming of biomass in fossil fuel based reformers

For reducing the net CO2 emissions of commercial gas (natural and associated) and naphtha reformers and lowering the investment costs and implementation barrier, co-reforming of biomass and a fossil feedstock seems very attractive. Pyrolysis oil (or its fractions) and glycerol (from bio-diesel production via transesterification) are interesting candidates as they can easily be pressurized and are relatively clean feedstocks. Biogas (essentially CH4 and CO2) from digesters could be interesting only if they are available in significant quantities at the location of the reformer. The installation of a dedicated pre-reformer for the bio-feedstock would be desirable for the following reasons: (i) minimal changes have to be made to the existing reformer since a methane and hydrogen-rich gas is being fed instead of the original oxygenated compound. (ii) Since co-reforming is considered, the full amount of steam needed for the reformer can be fed to the pre-reformer. The pre-reformer can then operate on very high S/C ratios which is beneficial for the gas chemical equilibrium and minimizes coke formation for which oxygenated compound have a higher tendency to compared to its fossil counterparts. (iii) Impurities like sulfur in the bio-based feedstock are bound to the pre-reformer catalyst acting as a guard bed for the subsequent reformer. Fossil fuel impurities are removed prior to entering the reformer, but this is often not possible for the bio-feedstock due to its high reactivity. In this way, only the pre-reformer catalyst has to be regenerated

periodically. A conceptual scheme of bio-liquid co-reforming is given in Figure 20.4.