H2-rich synthesis gas production over Co/Al2O3 catalyst via glycerol steam reforming

Alumina-supported cobalt catalyst has been employed in a fixed bed reactor for the direct production of synthesis gas from glycerol steam reforming. Physicochemical properties of the Co/Al2O3 catalyst were determined from N2 physisorption, H2 chemisorption, CO2 and NH3-temperature-programmed desorption measurements as well as X-ray diffraction analysis. Both weak and strong acid sites are present on the catalyst surface. The acidic:basic site ratio is about 6. Glycerol steam reforming gave relatively large H2:CO ratio (6 to 12) and near-stoichiometric values of H2:CO2 ratio (2 to 2.30) were obtained depending on feed composition (30 to 60 wt.% glycerol mixture). The glycerol consumption rate appeared to be a weak function of glycerol (0.1) and has 0.4 order with respect to the steam partial pressure. Increased glycerol partial pressure led to high carbon deposition (total organic carbon values of 20 to 24%). However, removal of the deposited carbon was essentially complete following a temperature-programmed oxidation (air)–temperature-programmed reduction (H2) scheme.

Graphical AbstractFig. 0A. The transient dry composition profiles of H2 (●), CO2 (○), CO (▼) and CH4 (X) in glycerol steam reforming. Conditions: 823 K; Pglycerol = 7.40 kPa, Psteam = 57.0 kPa; WHSV = 5.0 × 104 mL gcat−1 h−1.Fig. 0B. Selectivity of product as function of Pglycerol and Psteam at 823 K.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch Highlights► Co/Al2O3 catalyst may be used for glycerol steam reforming to yield H2-rich syngas. ► The conversion appeared to occur on strong acid sites. ► Glycerol reforming showed order of 0.1 for glycerol and 0.4 for steam. ► Carbon deposition was significant even under the stoichiometrically excess steam. ► TPO–TPR and TPR–TPO showed formation of at least two types of surface carbon pools.