In this work, the further development of the molten metal capillary reactor in slug-flow regime is presented. The preliminary results from the high-temperature pyrolysis of methane at 1300 degrees C and 9 Nm/min are presented with a calculated conversion of 80%, and, a mean residence time of 1.36 s. Due to carbon deposition, difficult gas separation and unstable slug-flow, it was deemed necessary to redesign the system. For that, several alloys were tested looking for improved wettability and more favorable hydrodynamics. The modified experimental set-up is described, which led to improvements in gas separation, but not enough stability in the slug-flow. Finally, the current experimental set-up is introduced. There, a characterization of the hydrodynamics is performed using a low temperature alloy of gallium, indium and tin, GaInSn, and, a stable regular slug-flow is established for various gas and liquid flows. The presence of a film in the slug-flow remains subject to question and the conclusions on the direction of the project are drawn towards an alternative reactor system or further hydrodynamic studies. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.