Advanced biofuel from various lignocellulosic feedstocks by liquid phase pyrolysis - the bioCRACK pilot plant
1J. Ritzberger, 1P. Pucher, 2N. Schwaiger, 2M. Siebenhofer
1BDI – Bioenergy International AG, Parkring 18, 8042 Grambach, Austria, e-mail: email@example.com
2Graz University of Technology, Institute of Chemical Engineering and Environmental Technology, Inffeldgasse 25/C/II, 8010 Graz
Currently almost all commercial available biofuels compete with food and animal feed production. Advanced biofuels are expected to be produced from non-food feedstock. They will play an important role in generation of renewable liquid energy carriers. The bioCRACK process represents a biomass-to-liquid concept for generating advanced biofuels, technologically based on liquid phase pyrolysis. Spruce wood, wheat straw, beech wood and miscanthus is the selected lignocellulosic feedstock. Preferred heat carrier is vacuum gas oil, an intermediate from vacuum distillation of crude oil. Lignocellulosic biomass is processed in vacuum gas oil at temperatures of 350°C to 400°C and ambient pressure. During liquid phase pyrolysis the feed is transferred into hydrocarbons, liquid CHO-products, reaction water, biochar and gaseous products. Technology as well as the type of heat carrier suggest integration of the process in an oil refining concept. Crude products from liquid phase pyrolysis and the spent heat carrier can be upgraded in existing facilities of the refinery. For instance, the crude product is upgradeable to diesel fuel via hydrogenation.
From 2012 to 2014 a fully integrated bioCRACK pilot plant with a design capacity of 100 kg/h was in continuous operation at the OMV oil refinery in Schwechat/Austria. Within two and a half year of intensive research the influence of various lignocellulosic feedstocks (spruce wood, beech wood, wheat straw and miscanthus), different biomass impregnation (high and low boiling refinery intermediates), operation parameters, yield and composition of the products, the mutual interaction of the feed and the heat carrier and the impact of process conditions and products on the refining process have been investigated.
Within the design temperature span (350 °C to 400 °C) the liquid phase pyrolysis of the deployed feedstocks showed comparable results. Mass balances and C14-tracking confirmed bio-carbon transfer from lignocellulosic feed into crude product fuels of 10 to 20 %. 9% to 18 % of the bio-carbon is transferred into the heat carrier. It was shown that the combined conversion of lignocellulosic and vacuum gas oil by liquid phase pyrolysis has an accelerating impact on the decomposition of the heat carrier oil. In conclusion the bioCRACK process may significantly contribute to providing advanced biofuels from lignocellulosic biomass as well as generation of low molecular weight intermediates from vacuum gas oil.
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