The passive production of synthesis gas from liquid methanol using a packed bed of porous material particles supporting a catalyst is investigated. Heating of the upper portion of a vertical tube packed with the porous particles where the bottom is immersed in liquid methanol is expected to cause steady upward fluid flow due to capillary action enhanced by evaporation. The emergence of a dry region and a resulting increase in temperature can produce synthesis gas due to catalytic reaction, which then flows out of the top end of the tube. In the proposed process, the capillary force, which is dependent on the local liquid content in the porous bed, is balanced locally with the gravitational force and the viscous forces acting on the liquid and vapor. The distributions of the liquid content, flow rates, pressures, and temperatures of liquid and vapor along the tube axis are calculated using a one-dimensional model based on the mass, force, and energy balances for each phase. The experimental results indicate the validity of the process, that is, the induction of steady fluid flow, the emergence of a dry region, temperature increase to the reaction level, and the products of the reacted gases. The behavior of liquid-vapor flow induced by phase-change in a packed bed and the factors that characterize the process and affect the performance are discussed. (C) 2018 Elsevier Ltd. All rights reserved.