• Wellach, S.
• Mirodatos, C.
• Schuurman, Y.
• Venderbosch, R.
• Chapelliere, Y.
• Jordan, E.
• Tuel, A.

Abstract

In order to meet the EU’s renewable energy targets by 2020 (up to 10% share in all forms of transportation fuels1), a realistic alternative to first generation bio-fuels is to produce hybrid bio/fossil fuels by co-refining biomass pyrolysis liquids (PL) with crude oil fractions in a conventional oil refinery2. However, co-refining may lead to severe changes in products quality, such as a higher aromaticity and residual oxygenates in the hybrid fuels that are produced. For the case of co-FCC (fluid catalytic cracking), various strategies can be implemented to limit those impacts along this complex value chain ranging from bio-mass to bio-gasoline.A first strategy was tested to preserve the gasoline yield and quality by implementing a PL hydrotreating prior to co-processing, to lower their oxygen content3. However, to reduce the cost impact of hydrogen consumption for severe hydrotreating levels, a balance in PL upgrading severity/efficiency has to be found4. This presentation will analyze the changes in conversion, yields and gasoline composition (aromatics/olefins vs saturated alkanes) as a function of the bio-oils hydrotreating severity, measured in a Micro Activity Test (MAT) reactor. It will be shown that a compromise can be reached between bio-oil upgrading severity and FCC products yields and quality (RON, PIONA analysis).A second strategy was to adapt the FCC catalysts to the presence of oxygenate molecules typical of the bio-feedstock still present in the upgraded pyrolytic liquids. To that end, Y zeolites, which are the main active component in FCC catalysts, were up-graded by creating a mesoporosity in addition to the microporosity to favor the diffusion of the large lignocellulosic fragments throughout the cracking catalysts, according various hierarchical post synthesis processes5,6. It will be shown that significant changes in the gasoline composition (essentially aromaticity, olefinicity, together with coke formation) can be achieved by these processes, based on major changes in porosity and intrinsic diffusivity of feed molecules.The never reported combined impact for these two strategies on the co-FCC efficiency will be discussed as a potential guideline for minimizing the cost of bio-oils upgrading and thereof the hybrid transportation fuels, while maintaining their quality.

Topics

• pyrolysis
• impedance spectroscopy
• Oxygen
• Hydrogen
• porosity
• diffusivity
• alkane
• intrinsic diffusivity