The present work studies the influence of the temperature (200-240 ºC), pressure 12 (38-50 bar), glycerol concentration (10-50 wt.%) and mass of catalyst/ glycerol mass 13 flow rate ratio (W/m glycerol = 10-40 g catalyst min/g glycerol) during the aqueous 14 phase reforming (APR) of a glycerol solution obtained from the production of 15 biodiesel. The operating conditions exerted a statistically significant influence on the 16 reforming results. Specifically, the global glycerol conversion and the carbon 17 converted into gas and liquid products varied as follows: 4-100%, 1-80% and 16-18 93%, respectively. The gas phase was made up of H 2 (8-55 vol.%), CO 2 (34-66 19 vol.%), CO (0-4 vol.%) and CH 4 (6-45 vol.%). The liquid phase consisted of a 20 mixture of alcohols (monohydric: methanol and ethanol; and polyhydric: 1,2-21 propanediol, 1,2-ethanediol, 2,3-butanediol), aldehydes (acetaldehyde), ketones (C3-22 ketones: acetone and 2-propanone-1-hydroxy; C4-ketones: 2-butanone-3-hydroxy 23 and 2-butanone-1-hydroxy; and cyclic ketones), carboxylic acids (acetic and 24 propionic acids) and esters (1,2,3-propanetriol-monoacetate), together with unreacted glycerol and water. The relative amount (free of water and un-reacted glycerol) of 1 these compounds in the liquid phase was as follows: monohydric alcohols: 4-47%, 2 polyhydric-alcohols: 14-68%, aldehydes: 0-5%, C3-ketones: 2-33%, C4-ketones: 0-3 10 %, ciclo-ketones: 0-6%, carboxylic acids: 2-43%, and esters: 0-46%. This process 4 turned out to be highly customisable for the valorisation of crude glycerol for the 5 production of either gaseous or liquid products. Gas production is favoured at a low 6 pressure (39 bar), high temperature (238 ºC), high W/m glycerol ratio (38 g catalyst 7 min/g glycerol) and employing a 15 wt.% glycerol solution. A high pressure (45 bar), 8 medium temperature (216 ºC), medium W/m glycerol ratio (22 g catalyst min/g 9 glycerol) and the feeding of a 16 wt.% glycerol solution favours the production of 10 liquid products.
