In this paper, we investigated the gasification of charcoals using a macro TG under CO 2 mixed with nitrogen at different percentages (40%, 70% and 100% CO 2 ) and at different fixed temperatures (750°C, 800°C, and 900°C). For this purpose, two raw residues were selected; the exhausted olive mill solid wastes (EOMSW) and the pine sawdust (PS). Then, four different samples, which have not been previously studied with a gasification process, were prepared from these residues when investigating the impregnated and the non-impregnated ones using the olive mill waste water (OMWW) as by-product for the impregnation process. Moreover, a comparison between results obtained during this study and those obtained during a previous study based on steam gasification was carried out. It was found that the mass loss profiles are consistent with the usual lignocellulosic gasification behaviors. Also, the increase of temperatures or CO 2 percentages affects positively the conversion, the gasification rate and the char reactivity. It is worth noting that CO 2 acts differently from steam. With steam, gasification is found to be faster and more reactive.

Green waste and wood gasification have been studied through a non-catalytic process. Experiments are conducted at a pilot-scale developed at RAPSODEE Centre to validate the feasibility of producing high-quality nitrogen-free syngas. Biomass is first pyrolyzed at 800 • C in a rotary kiln. Then, the volatile matter is cracked and reformed in a non-catalytic tubular reactor. Effects of temperature and gas residence time in the tubular reactor on the process performances are evaluated. The results show that the tar formed in the first stage for each biomass is mainly converted into soot inside the second one. The soot yield has reached 11.5 wt% at 1300 • C with a gas residence time of 10 s. Wood tar appears to have a different suite of compounds than tar from green waste; they probably have different cracking pathways. The wood tar conversion ratio has achieved 98.8% at 1300 • C with a gas residence of 5 s while it reaches only 80.4% for green waste. Under these operating conditions, the lower heating value of syngas is around 11 MJ/Nm 3 . The syngas obtained is rich in H 2 (up to 50 vol %) and CO (up to 35 vol%) and contains CO 2 (<10 vol%) and CH 4 (< 5 vol%).