Catalytic hydropyrolysis of biomass using supported CoMo catalysts – Effect of metal loading and support acidity. (15th March 2020)

• Record Type: Journal Article
• Authors: Stummann, Magnus Zingler; Elevera, Elaine; Hansen, Asger Baltzer; Hansen, Lars Pilsgaard; Beato, Pablo; Davidsen, Bente; Wiwel, Peter; Gabrielsen, Jostein; Jensen, Peter Arendt; Jensen, Anker Degn; Høj, Martin
• Is Part Of: Fuel. Volume 264(2020)
• Publication Date: 2020-03-15
• Subjects: Biomass -- Molybdenum sulfide -- Hydrodeoxygenation -- Zeolite -- Biofuel; AED Atomic emission detector -- BET Brunauer–Emmett–Teller -- CUS Coordinatively unsaturated sites -- daf Dry, ash free basis -- db Dry basis -- DDO Direct deoxygenation -- diAro Diaromatics -- EDS Energy dispersive X-ray spectroscopy -- FB Fluid bed -- FCC Fluid catalytic cracking -- FID Flame ionization detector -- GC Gas chromatograph -- HAADF High-angle annular dark-field -- HDO Hydrodeoxygenation -- HYD Hydrogenation -- ICP-OES Inductive coupled plasma optical emission spectroscopy -- mAro Monoaromatics -- MgAl MgAl2O4 -- MS Mass spectrometry -- Naph Naphthenes -- O-Ali Oxygenated aliphatics -- O-Aro Larger oxygenated aromatics -- Par Paraffins -- PhOH Phenolics -- Ph(OH)2 Dihydroxybenzene -- SSA Specific surface area -- SEM Scanning electron microscopy -- STEM Scanning transmission electron microscopy -- TAN Total acid number -- Temp. Temperature -- TPD Temperature programmed desorption -- tetAro+ Tetra- and higher aromatics -- triAro Triaromatics -- ZA H-ZSM-5 mixed with Al2O3; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2019.116807
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Abstract: Catalytic hydropyrolysis of biomass to green fuels was performed using supported, sulfided CoMo catalysts. With MgAl2 O4 as support material the CoMo loading was varied between 4.1 and 12.0 wt% at constant Co/Mo atomic ratio of 0.3. Increasing the metal loading decreased the amount of oxygen in the condensed organic phase from 9.0 to 4.7 wt% on dry basis (db) and the condensable organic yield decreased from 25.2 to 22.7 wt% on dry ash free (daf) basis, corresponding to a decrease in the carbon recovery from 39 to 37%. Using zeolite H-ZSM-5 mixed with alumina as support with a CoMo loading of 4.1 wt%, the condensed organics contained only 5.2 to 6.1 wt% db oxygen. The condensable organic yield was between 23.9 and 24.4 wt% db, and the carbon recovery was 39–40%. Thus using an acidic support can remove the oxygen without decreasing the carbon recovery. The latter was ascribed to alkylation of the aromatics when the zeolite support was used. Elemental maps of the spent catalysts were obtained using STEM-EDS, showing that the CoMo phase was mainly located as monolayer MoS2 slab structures (>93%) on the support and indicated a high dispersion of cobalt, consistent with incorporation of Co into the MoS2 structure in the CoMoS phase. Potassium was observed on all the spent catalysts, indicating transfer of alkali metal from the biomass to the catalyst. Potassium may decrease the acidity of the catalyst over time, thus reducing the positive effect of using a more acidic support.