Experimental characterization of an additively manufactured reactor concept for catalytic methanation with in-situ tar co-reforming of biogenic syngas

• Experimental characterization of the 3D-printed ADDmeth3 methanation reactors. • Steady-state and transient operation. • In-situ co-reforming of tar components. • Catalyst screening for the in-situ co-reforming of tar components. Renewable methane is thought to play a major role in future energy systems. One approach to produce renewable methane is the methanation of syngas from biomass gasification. However, one of the main downsides to this process are high methane production costs. The extensive gas-cleaning necessary for tar removal is a major cost-driver. Another possible route for tar removal is the in-situ co-reforming of tar, where tar components are reformed directly during the methanation reaction, utilizing the heat-of-reaction of the exothermic methanation. The choice of a suitable catalyst is key for the co-reforming of tar. Five different commercial catalysts are subject to catalyst screening, with standard nickel catalysts performing better than noble metal catalysts when taking costs into account. We examine a novel approach for tar removal using a 3D-printed methanation reactor concept (ADDmeth3), featuring a high-temperature zone at the inlet for in-situ tar reforming. Two competing reactor designs (ADDmeth3.1 and ADDmeth3.2) are assessed together with the previously existing version (ADDmeth1) in benchmark experiments. The main design goals are met or exceeded, improving the feed gas power from 2.1 kW in ADDmeth1 to over 10.1 kW in ADDmeth3.2. After sudden load shifts, the reactor returns to steady-state operation within minutes. ADDmeth3.2 performs better overall and is used as ADDmeth3 in experiments with the addition of model tar components (benzene, toluene and indene) at high tar-loads. ADDmeth3 is capable of reducing the benzene content by 95 to 97 %. The other components are removed to a lesser extent (toluene by 35 to 64 %, indene is removed completely in most cases, some samples show up to 70 % of the initial indene content hydrogenated to form indane).