Flowability Control of Bed Materials in a Fluidized Bed Reactor for Solar Thermochemical Process

Abstract

Abstract Hydrogen production by solar thermochemical process uses concentrated solar radiation as its energy source. Various thermochemical processes operating at technically manageable temperatures which are a solar thermochemical two-step water splitting and solar gasification of carbonaceousmaterial have been extensivelystudied and demonstrated by researchers around the world. These processes arecapable of converting high-temperature heat from concentrated solar radiation into clean hydrogen from water.In this study, in order to control a flowability (fluidization state) of bed materials in a fluidized bed reactor for thermochemical processes (two-step water splitting cycle and gasification of coal coke),firstly, a basic relationship between pressure drop of inlet gas and gas flow rate was experimentally examined using bed materials with different particle sizes by a small-scale quartz reactor at ambient pressure and temperature. Secondly, the CeO2 particles having the size determined by above-describedflowability test were tested using a windowed fluidized bed reactor prototype. The fluidized bed of CeO2 particles was exposed to a concentrated Xe light by sun-simulator with an input power of about 5 kWth for the T-R step in order to release oxygen. The production rate and productivity of oxygen and the reactivity of CeO2 particles were examined in this paper.