Overall Process Integration:
Specification and limits for target fuels, testing protocols, benchmark and key performance indicators have been established. Twelve value chains were selected for techno-economic assessment (TEA) in which eight underwent detailed TEA. Mass, energy and elemental balances for the pre-processing steps in fast pyrolysis and hydrothermal liquefaction (HTL) have been retrieved. For the HTL process, Life Cycle Analysis (LCA) with 60% heat recovery has been developed and analysed.
Public perception of Danish debate on liquid biofuels reveals limited knowledge in media coverage of the topic. While there exists an overall positive perception in academia towards second generation biofuels for transportation, the mass media apply an overall negative discourse against biofuels. Only about 25% of the press mentions differentiate between different generations of biofuel. Furthermore, only 40% of these simply states that there are two different generations of liquid biofuels, without giving any further explanation.
Primary Conversion:
A total of 100 litres of an initial reference stabilized pyrolysis oil (SPO) 60 kg of a reference HTL bio-liquids and 310 kg of pyrolysis oil (PO) have been produced and delivered to partners. The two alternative reference bio-oils have been investigated in co-refining steps in order to establish the basis for selecting the optimal co-refining routes, as determined by the feedstock and end use application.
With respect to the primary conversion of the biomass to intermediate bio-oils, a number of approaches have been evaluated to optimise the efficiency and cost of the process.
Refining Processes:
In order to establish the basis for selection of the optimal routes for integration of the intermediates from primary conversion of biogenic feedstocks into the refinery all the major co-FCC and co-HDT refinery processes were explored. This involved co-refining of both pyrolysis and HTL bio-liquids produced from all three types of biomass feedstocks (forest residue, eucalyptus, straw).
Miscibility studies have shown that HTL bioliquids are incompatible with straight run gas oil (SRGO). Commercial surfactants have proven to be inefficient. Nevertheless, substantial amount of HTL bioliquids can be solubilized in SRGO by using co-solvents. Interestingly, the heavy distillate fractions derived from the fractional distillation of HTL biocrude showed complete miscibility in SRGO at any proportions. These studies show that fractional distillation is an efficient concept for dividing biocrude oil into different chemical groups to produce transportation fuels.
For the co-FCC route, SDPO and SPO from forest residue, eucalyptus and straw were tested in an FCC pilot unit using an FCC equilibrium catalyst together with typical FCC feedstocks. For tests involving bio-liquids from the pyrolysis route, results foresee that only a mildly treated pyrolysis oil will be sufficient for integration via the co-FCC route. However, for the alternative co-hydrotreating route, a more severely deoxygenated treatment of the pyrolysis bio-liquid is currently required. Based on both technical feasibility and economic profitability, co-feeding SPO forest residue and eucalyptus to FCC has been categorized as the most promising scenarios for implementation for value chains based on pyrolysis liquids.
Economically less profitable, but technically more feasible and otherwise interesting options were co-feeding SDPO from forest residue in an FCC or HDO unit.
