The reduction reaction of copper oxide with CH4 is highly exothermic and can be arranged to generate sufficient heat to in-situ calcine calcium carbonate and produce a highly concentrated stream of CO2. This concept is tested at TRL4 in a packed-bed reactor operated close to adiabatic conditions. The impact of the initial solids temperature and the inlet flowrate of the gases is evaluated. A 50/50 (vol.%) mixture of methane and hydrogen (i.e., a possible composition of the PSA-off gas generated in a reforming process) has also been used as reducing gas. The presence of H2 reduces the CuO/CaCO3 proportion required in the bed and promotes the calcination at temperatures lower than 870 degrees C. The experimental measurements are well predicted by a one-dimensional fixed-bed reactor model, in which the steam methane reforming, water-gas-shift, carbon deposition and carbon gasification reactions are also considered. Different characterization techniques (i.e., SEM, XRD, N-2 adsorption, TPR) demonstrate that both commercial CuO- and CaO-based materials show good stability after successive cyclic experiments. (C) 2018 Elsevier Ltd. All rights reserved.