Flash co-pyrolysis of biomass: The influence of biopolymers

A high water content is one of the major drawbacks for the utilisation of bio-oil. One technology which shows the potential to satisfy the demand for bio-oil with a reduced water content is the flash co-pyrolysis of biomass with biopolymers. The influence of biopolymers on the pyrolysis yield of a biomass waste stream is investigated with a semi-continuous home-built pyrolysis reactor. Polylactic acid (PLA), corn starch, polyhydroxybutyrate (PHB), Biopearls, Eastar, Solanyl and potato starch are the biopolymers under investigation. All biopolymers show their specific benefits during flash co-pyrolysis with willow (target biomass) at 723 K. Each (co-)pyrolysis of pure willow (reference) and all 1:1 (w/w) ratio willow/biopolymer blends is evaluated based on five predefined criteria. A multi-criteria decision aid (MCDA) method ‘PROMETHEE’ is used in order to obtain an objective ranking of the different biopolymer options.The flash co-pyrolysis of biomass and biopolymers results in improved pyrolysis characteristics. The flash co-pyrolysis of 1:1 willow/PHB is the most performant option, while 1:1 willow/PLA, 1:1 willow/Biopearls and 1:1 willow/potato starch show increased potential as well. The fact that biopolymers, despite their biodegradability, should be considered as waste, further increases the appealing features of the flash co-pyrolysis of biomass and biopolymers.