Enhancement of biofuels production by means of co-pyrolysis of Posidonia oceanica (L.) and frying oil wastes: Experimental study and process modeling

•Posidonia oceanica and frying oil wastes are promising biomasses for co-pyrolysis.•The co-pyrolysis gave a better yield of bio-oil (37wt.%) at 500°C.•The syngas highest heating value is 20MJ/kg when H2/CH4 ratio is 33.16/36.31.•The biochar high heating value (19.409MJ/kg) was obtained for pyrolysis at 500°C.•The decomposition kinetic of solids was validated via linearized Arrhenius model. Energy recovery from lignocellulosic solid marine wastes, Posidonia oceanica wastes (POW) with slow pyrolysis responds to the growing trend of alternative energies as well as waste management. Physicochemical, thermogravimetric (TG/DTG) and spectroscopic (FTIR) characterizations of POW were performed. POW were first converted by pyrolysis at different temperatures (450°C, 500°C, 550°C and 600°C) using a fixed-bed reactor. The obtained products (bio-oil, syngas and bio char) were analyzed. Since the bio-oil yield obtained from POW pyrolysis is low (2wt.%), waste frying oil (WFO) was added as a co-substrate in order to improve of biofuels production. The co-pyrolysis gave a better yield of liquid organic fraction (37wt.%) as well as syngas (CH4,H2…) with a calorific value around 20MJ/kg. The stoichiometric models of both pyrolysis and co-pyrolysis reactions were performed according to the biomass formula: CαHβOγNδSε. The thermal kinetic decomposition of solids was validated through linearized Arrhenius model.