Aqueous-phase reforming of mannitol over Pt/C catalyst in a fixed-bed reactor

Abstract

Aqueous-phase reforming (APR) of macroalgal biomass is a candidate technique for hydrogen (H₂) production. In this work, mannitol was chosen as a model compound of brown macroalgae and H₂ was produced from APR of mannitol using a commercial Pt/C catalyst. Kinetics trials were performed in a fixed-bed reactor between temperature (T) 453 and 498 K and pressure (P) 1.2 and 2.4 MPa using 5, 10 and 15 wt% mannitol-containing feeds. The weight hourly space velocity (WHSV) was varied in the 0.15–0.6 1/h range. At T = 498 K and P = 2.4 MPa, turnover frequency of hydrogen (TOF-H₂ = 3.4 1/min), mannitol conversion (X = 82 %) and H₂ yield (Y–H₂ = 23.7 %) were determined. The reaction rate exhibited fractional order dependence on mannitol concentration. The activation energy for H₂ production was found to be 88.3 kJ/mol. In this way, this work provided useful information on mannitol-to-H₂ conversion by the APR process.