(Elsevier, 2025-08-01) Gracia Monforte, César; Maldonado-Martín, Francisco; Atienza Martínez, María; Ábrego, Javier; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa; Gobierno de Navarra / Nafarroako Gobernua
This study presents an experimental investigation into the feasibility of oxidizing biomass pyrolysis gases at
relatively low temperatures using a chemical looping combustion (CLC) approach. The application of this
alternative method would enable the capture of carbon from the pyrolysis gas stream, which is currently released
into the atmosphere in most pyrolysis systems, as high-purity CO2. In a fixed bed reactor, the reduction behavior
of three different Cu-based oxygen carriers (OC) - pure CuO pellets, carulite and Al2O3-supported CuO - was
evaluated to determine whether pyrolysis gases could be completely oxidized to CO2 and H2O within a temperature range of 600–650 ◦C and at weight hourly space velocities (WHSV) of 0.06–0.10 h− 1
. Both CuO and
carulite exhibited significant amounts of unconverted pyrolysis gases even during the initial stages of the
reduction experiments. In contrast, Al2O3-supported CuO emerged as the most effective material, facilitating the
complete oxidation of pyrolysis gases over extended reaction times. For this oxygen carrier, a decline in the
combustion efficiency was only observed at very high (90 %) reduction conversions. Reduction/oxidation cycles
for this most promising material were successfully demonstrated, with the oxygen carrier showing no signs of
activity loss after 10 cycles. However, carbon deposition was detected under several experimental conditions,
which could potentially reduce the carbon capture efficiency of the process.
