Design of a 10 MW Particle-Flow Reactor for Syngas Production by Steam-Gasification of Carbonaceous Feedstock Using Concentrated Solar Energy

Steam-gasification of carbonaceous feedstock is carried out in a solar reactor consisting of a cavity-receiver containing an array of tubular absorbers, through which a two-phase flow of water vapor laden with mu m-sized carbonaceous particles reacts to form H-2 and CO (syngas). Concentrated solar radiation, entering through the cavity's aperture, is supplied as the source of high-temperature process heat to the endothermic reaction. A heat transfer model is formulated by coupling radiation/convection/conduction heat transfer to the chemical kinetics for a solid-gas reacting flow. It is solved numerically by Monte Carlo and finite volume techniques. Experimental validation is accomplished for biochar gasification with a 3 kW prototype reactor subjected to high-flux thermal irradiation. The model is applied to analyze the performance of a 10 MW industrial-scale reactor mounted on a solar tower configuration. For an optimized reactor geometry and a desired outlet temperature of 1500 K, a solar-to-chemical energy conversion of 37% is predicted for 1500 suns solar concentraticn.