At the start of the project, biogenic waste fractions were selected to be tested by the conversion processes, fast pyrolysis and HTL. Among the feedstocks tested were the organic fraction of municipal solid waste, digestate from anaerobic digestion, husks from production of sunflower oil, food waste collected directly at canteens, contaminated waste wood, roadside grass cuttings and black liquor from paper industry. The waste fractions represent a wide variety of materials with very different properties, composition and level of contamination. Depending on the properties (moisture content), some feedstocks were tested by fast pyrolysis and some by HTL. The lab-scale tests provided invaluable information about the effect of process parameters on bio-oil quality which has been used to find optimum conditions for testing at pilot-scale level. After screening tests in the lab-scale pyrolysis and HTL units, several of the most promising feedstocks have been chosen for pilot-scale production of sufficient amounts of bio-liquids. Pilot-scale pyrolysis tests have been conducted with contaminated wood, roadside grass and sunflower husks, each producing several hundreds of kg of bio-liquids. Pilot scale continuous HTL tests have been carried out primarily with food waste collected from canteens, producing about 10 kg of bio-crude. An important focus in the project is removal of contaminants from the produced bio-oils, to avoid deactivation of catalyst in the upgrading steps.
The FCC pilot plant at TUW co-processed 10 wt% of a mixture of stabilized and deoxygenated pyrolysis oil (SDPO) and stabilized pyrolysis oil (SPO) from contaminated wood. The gasoline fractions of the liquid products produced were distilled and the following parameters of the gasoline fractions were analysed: density, moisture, CHNSO, inorganic contaminants, boiling curve and PIONA analysis. The analysis results indicate that the gasoline fractions produced from clean wood (reference sample) and contaminated wood are suitable as gasoline blending components. A mixture of 20wt% SDPO from contaminated wood with gasoil was co-processed in a large-scale hydroprocessing pilot plant. The final diesel was then tested at Centro Ricerche Fiat (CRF) for compliancy with current standard reference norms for automotive diesels. The parameters evaluated are all in line with the EN590 specifications. The diesel sample was also tested in a vehicle to evaluate the impact on the engine emissions. The results obtained are compliant with the limits prescribed by the standard regulation for the diesel engine emissions, in line with the emission obtained with a commercial fossil diesel
The HTL bio-crude produced in a continuous process from food waste is shown to be very viscous and sticky by nature, which makes its processibility challenging. The partners investigated different techniques to improve the flowability and found that vacuum distillation was most promising. The HTL bio-crude was co-HT at pilot scale with a rich HTL feedstock in light gas oil (LGO). It was demonstrated in a 24h long test period that this feed leads to middle distillate fuels with very low oxygen content.
WASTE2ROAD evaluated in more detail the value chains based on contaminated wood, sunflower husks, food residues and black liquor. Data on composition of the tested feedstocks and the produced intermediate bio-liquids have been collected and these have been used for process modelling, flow-sheeting, design plans, and techno-economic assessment of the process. The Key Performance Indicators (KPIs) have been defined and are used to evaluate the overall process performance from various perspectives (economical, environmental, etc.). WASTE2ROAD partners aim to contribute to development and standardization of techniques for characterization of bio-oils, where one challenge lies in accurately determining the fraction of bio-based fuels in co-processed fuels (green carbon tracking).
