Membrane Fractionation of Biomass Fast Pyrolysis Oil and Impact of its Presence on a Petroleum Gas Oil Hydrotreatment

Abstract

Membrane Fractionation of Biomass Fast Pyrolysis Oil and Impact of its Presence on a Petroleum Gas Oil Hydrotreatment—In order to limit the greenhouse effect causing climate change and reduce the needs of the transport sector for petroleum oils, transformation of lignocellulosic biomass is a promising alternative route to produce automotive fuels, chemical intermediates and energy. Gasification and liquefaction of biomass resources are the two main routes that are under investigation to convert biomass into biofuels. In the case of the liquefaction, due to the unstability of the liquefied products, one solution can be to perform a specific hydrotreatment of fast pyrolysis bio-oils with petroleum cuts in existing petroleum refinery system. With this objective, previous studies [Pinheiro et al. (2009) Energy Fuels 23, 1007-1014; Pinheiro et al. (2011) Energy Fuels 25, 804-812] have been carried out to investigate the impact of oxygenated model compounds on a Straight Run Gas Oil (SRGO) hydrotreatment using a CoMo catalyst. The authors have demonstrated that the main inhibiting effects are induced from CO and CO2 produced during hydrodeoxygenation of esters and carboxylic acids. To go further, cotreatment of a fast pyrolysis oil with the same SRGO as used in the previous studies was investigated in this present work. Firstly the bio-oil was separated into four fractions by membrane fractionation using 400 and 220 Da molecular weight cut-off membranes. The bio-oil and its fractions were analyzed by spectroscopic and chromatographic techniques. Then, one fraction (i.e. fraction enriched in compounds with molecular weight from 220 to 400 Da) was mixed with the SRGO and co-treated. Despite some experimental difficulties mainly due to the emulsion instability, the hydrotreatment was successful. An inhibition has been observed on the hydrotreating reactions of the SRGO in presence of the bio-oil fraction. The measurement of the CO/CO2/CH4 molar flowrate at the reactor outlet showed that the inhibition was due to the presence of CO and CO2 coming from HDO rather than to the oxygen compounds themselves. © 2013, IFP Energies nouvelles.