# Life Cycle Assessment on a Biorefinery Approach to Pyrosis Oil for Wood Modification Treatment
###### Abstract  
The use of pyrolysis-based wood conservation is a good alternative for the use of fossil-based creosotes. In this life cycle assessment (LCA) the environmental impact of a biorefinery approach of pyrolysis oil from forestry residues or maize digestate and its application as wood modification treatment is determined. The damage to ecosystems, damage to human health and the increased resource scarcity is studied using an attributional LCA and a sensitivity and uncertainty analysis. Based on data from an existing pyrolysis plant, it is shown that pyrolysis oil from maize digestate has a significantly higher environmental impact than pyrolysis oil from forestry residues. This is due to a lower energetic yield and a higher ash content in the feedstock. The biorefinery approach of using pyrolytic sugars as wood modification treatment shows significantly lower environmental impacts than the fossil-based creosotes, regardless of the selected end of life scenario, due to a lower toxicity and by a reduction of 82% of greenhouse gases. This shows that in addition to energy production, pyrolysis oil can be applied as biophysical chemicals and materials, developing a sustainable platform based on pyrolysis oil. Keywords:pyrolysis; biorefinery; wood modification; LCA; biobased; creosote +
Footnote †: journal: Applied  
Fast pyrolysis is a technique that produces a homogeneous liquid from biomass by rapidly heating the biomass to 400-600 \({}^{\circ}\)C in the absence of oxygen. Pyrolysis liquid, also called pyrolysis oil due to its oily appearance, can be directly applied for combustion to energy, or it can be upgraded to biofuel or biochemicals [6; 7; 8; 9]. During the process, a complex mixture of mostly liquid components is formed, with a small amount of char and non-condensable gases. Due to the complexity of the mixture, the interactions between components, potential heat transport limitations, and the short lifespan of some of the components, the kinetics of pyrolysis is not yet fully understood and may change depending on the type of feedstock [6]. Several technologies have been developed aiming to concentrate the energetic value of biomass in a homogeneous, rather stable, pumpable liquid, while removing the ash. The remaining energy, e.g., from the non-condensable gases, can be used for the production of bioenergy [10]. For example, Ensyn has developed a rapid thermal processing (RTP) technology in North America, using a circulating fluid bed system. Dynamotive Technologies acquired a pyrolysis technology on the basis of indirect heating of a fluidized bed. In Europe, VTT has developed a pyrolysis technology based on the integration of fast pyrolysis into a fluidized bed reactor, combining the pyrolysis with a combined heat and power (CHP) plant [10]. Finally, BTG developed a pyrolysis technique based on a rotating cone. The simplification of this reactor design eases the scaling-up process, which is highlighted by the announcement of several pyrolysis plants being constructed in Scandinavia using this technique [11]. While these technologies focus on the use of pyrolysis oil for energy purposes, within the Horizon2020 project, Bio4 Products aims at developing a technology to divide pyrolysis oil into multiple fractions that could be used for material applications. Many new products could be developed from pyrolysis; an example is the separation of pyrolysis oil into two fractions, a pyrolytic sugar fraction and a pyrolytic lignin fraction. The lignin fraction could find applications in phenolic resin substitution, where the pyrolytic sugar fraction could substitute creosotes as a wood modification treatment. Research in the field of rapid pyrolysis and product analysis of creosote treated woods is limited [12]. Especially when it comes to life cycle assessment (LCA) studies there are few studies concerning creosote alternatives. [13]. Moreover, current LCA studies are based only on modeling data [14; 15; 16; 17; 18].