Sustainable bio kerosene: Process routes and industrial demonstration activities in aviation biofuels

Abstract

Alternative fuels are expected to play a major role in EU in the coming years due European Directives on the promotion of renewable energies and reduction of greenhouse gas emissions in transports. However, while in road transports a variety of possible renewable fuels (mainly biofuels, but also electricity) can be considered, in aviation only high quality paraffinic biofuels can be adopted. This means that biomass must be converted through advanced processes into pure hydrocarbon fuels, fully compatible with the existing systems. The aviation sector is responsible for the 2% of the world anthropogenic CO2 emissions and the 10% of the fuel consumption: airlines’ costs for fuel reach 30% of operating costs. In addition, the aviation traffic is expected to double within 15years from 2012, while fuel consumption and CO2 emissions should double in 25years. Thus, more than 2 billion people and 40 Mt of good/cargo will have to be moved every year. In this context, the EU Flightpath set a target of 2Mt per year for aviation alternative fuel by 2020 (i.e. 4% of annual fuel consumption). New processes towards bio-hydrocarbons are being developed, demonstrated and soon industrialized.The present work explores the possible routes from biomass feedstock to sustainable paraffinic fuels, either through bio or thermo-chemical processes, as well as discusses those more mature, focusing on industrial demonstration initiatives. In fact, while the number of possible options towards paraffinic biofuel production is very large, and covers both thermochemical and biochemical routes, as well as hybrid one, only two pathways are today ready for testing a significant large scale: these are FT and Hydrotreating. Major industrial activities and testing experiences are thus reported in the present work.In this context, the ITAKA group is developing a full value-chain in Europe to produce sustainable drop-in Synthetic Paraffinic Kerosene (SPK) – called HEFA – in an economically, socially and environmentally sound manner, at large scale enough to allow testing its use in existing logistic systems and in normal flight operations in Europe. The generated knowledge will aim to identify and address barriers to innovation. Within ITAKA, possible pre-processing of used (waste) cooking oil (UCO) to make it compatible with current downstream hydroprocessing techniques are being investigated: this can includes esterification of waste oils, as well as catalytic thermal processing, which will be carried out in a pilot unit available at RE-CORD/CREAR. First samples of feedstock oils were collected and characterized, for further investigation towards their conversion into biokerosene through hydrotreatment.