Molten-Salt Tubular Absorber/Reformer (MoSTAR) Project: Metal-Plate-Bridged Double Tube Reactor

The Molten-Salt Tubular Absorber/Reformer (MoSTAR) Project, which is jointly conducted by Niigata University, Japan, and Inha University, Korea, aims to develop a novel-type of “double-walled” tubular absorbers/reformers with molten-salt thermal storage at high temperature for use in solar natural-gas reforming and solar air receiver, and to demonstrate their performances on sun with a 5-kW_t dish-type solar concentrator. The new concept of “double-walled” reactor tubes was proposed for use in a solar reformer by Niigata University, Japan, and involves packing a molten salt in the annular region between the internal catalyst tube and the exterior solar absorber tube of the double reactor tube. In this work, “metal-plate-bridged” double reactor tubes are newly proposed for use in a solar reformer. Two different sized reactor tubes are constructed, and tested on chemical reaction performance for dry reforming of methane during cooling or heat-discharge mode of the reactor tube using an electric furnace. The experimental results obtained under feed gas mixture of CH₄/CO₂ = 1:3 at a residence time of 0.36 s and at 1 atm showed that the double reactor tube with the heat storage medium Na₂CO₃ in the annular region successfully sustained a high methane conversion above 90% with about 0.7-kW output power of the reformed gas based on HHV for 40 min of the heat-discharge mode. The application of the new reactor tubes to solar tubular reformers is expected to help realize stable operation of the solar reforming process under fluctuating insolation during a cloud passage.