A system for producing a syngas from a biomass material. The system compacts a loose biomass material to form a compacted biomass material at an entrance of a reactor tube, and then heats the compacted biomass material within the tube to form ash and a fuel gas mixture. The fuel gas mixture is withdrawn from the tube and the ash is removed from the tube through an exit thereof. Ingress of air into the tube is inhibited by forming a plug of the biomass material at the entrance of the tube and a plug of ash at the exit of the tube. A neutral atmospheric pressure is maintained in the reactor tube relative to pressure outside the reactor tube by monitoring and adjusting a volumetric rate of the fuel gas mixture withdrawn from the reactor tube based on pressures at the entrance and the exit of the reactor tube.