Thermochemical conversion routes of lignocellulosic biomass ; Voies thermochimiques de valorisation de la biomasse lignocellulosique
The thermo-chemical route, especially the gasification process is considered. This process converts carbonaceous biomass into combustible gas (CO, H2, CO2, CH4 and impurities) called syngas and this syngas can be converted into a large range of products. Production of four of these compounds is specifically investigated: ethylene, propylene, diesel and DME. Diesel can be produced via a Fischer-Tropsch process, whereas DME (dimethyl ether) can be obtained directly or from methanol which is obtained from syngas. DME and diesel can serve as fuels in traditional motors. Syngas can also be used to produce ethylene and propylene, two building blocks for the chemical industry. An important bibliography study has been done to understand these processes in order to evaluate their environmental impacts. The Life Cycle Assessment (LCA) methodology will be used in this regard. A bibliography study on the LCA articles published in this filled has been performed and it appears that few studies have yet focused on the environmental impacts of the gasification process and production of biofuels. Most of the time, they do not use the LCA methodology or they do not take into account land use change impact and are only "well-to-tank" studies. Moreover, it seems that the production of building blocks for the chemical industry has never been investigated. During the next stages of this work, the best conversion routes of lignocellulosic biomass, in an environmental sense, will be determined. Gasification will also be compared with the fossil sector and the results will be checked by sensitivity and uncertainty analyses. The economic aspect will also be taken into account, for the better process, in an environmental view. So, the results of the full study will be a decision making tool for the industries involved in biomass valorisation and for governments. ; Peer reviewed