Steam reforming of pyrolysis oil aqueous fraction obtained by one-step fractional condensation

摘要

The aqueous fraction of pyrolysis oil, which was produced and fractionally condensed in VTT's 20 kg/h fast pyrolysis Process Development Unit, was successfully steam reformed in a fixed-bed reactor over a commercial nickel catalyst without any additional steam. As a result of the one-step fractionation process, the aqueous pyrolysis oil, which had a water content of 72.7 wt%, contained only limited amounts of thermally unstable sugar-type compounds that typically hinder the performance of catalytic steam reforming. An average hydrogen yield of 81% was achieved over two hours at relatively mild process conditions: 650 degrees C, steam-to-carbon ratio of 3.84 and gas hourly space velocity of 5000 h(-1). When the reaction temperature was varied between 600 and 750 degrees C, clear catalyst deactivation was only observed at 600 degrees C. In theory, by utilizing the one-step fractional condensation scheme and subsequently steam reforming the aqueous pyrolysis oil, sufficient amounts of hydrogen could be generated for significantly deoxygenating the organic pyrolysis oil via catalytic hydrodeoxygenation. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.