Internally-circulating fluidized bed reactor using thermal storage material for solar coal coke gasification

摘要

A windowed reactor prototype of internally-circulating fluidized bed is tested and demonstrated at laboratory scale for steam gasification of coal coke irradiated directly by concentrated Xe light from a 3-kW_(th) sun simulator. The bed material is composed of particle mixture of coal coke and quartz sand. A coal coke of the bed material works as a carbonous feedstock, while quartz sand functions as a thermal storage/transfer medium inside the reactor. The fluidized bed reactor, having a transparent window due to incoming radiation of concentrated solar beam on the ceiling of the reactor, is designed to be combined with a solar reflective tower or beam-down optics. A potential of quartz sand in the internally-circulating fluidized bed reactor is evaluated for steam gasification of coal coke by gasification performance (CO, H2 and CO2 production rates, carbon conversion, and light-to-chemical efficiency). The gasification performances for use of the particle mixture in the reactor are compared with that for use of coal coke particle. The fluidized bed of a particle mixture including coal coke and quartz sand was gasified at lower temperature with a higher rate in comparison to that of a coal coke. Furthermore, a use of smaller and lighter coal coke particles were easily converted to gaseous species due to larger surface area as well as the gasification rates.