Numerical Simulation of Fluidized Bed Gasifier Coupled with Solid Oxide Fuel Cell Fed with Solid Carbon

Abstract

A model of a fluidized bed coupled with direct carbon solid oxide fuel cell (SOFC) is developed to explore the effect of coupling between fluidized bed and solid oxide fuel cell. Three gas–solid flow regimes are involved including fixed bed, delayed bubbling bed and bubbling bed. The anode reaction of SOFC is treated as the coupling processes of Boudouard gasification of carbon and electrochemical oxidation of CO. The effects of inlet velocity of the fluidizing agent CO2, carbon activity, channel width and coupling extent on the system performance are investigated. The results show that the inlet velocity of CO2 can promote the gasification rate in the anode, but too high velocities may lower CO molar fraction. The gasification rate generally increases with the increase of the channel width and carbon activity. The overlapping area between the anode surface and the initial carbon bed, gas–solid regime and carbon activity have a significant influence on the gasification rate and the maximum current density the system can support. Overall, the mass transport in the anode is dramatically enhanced by the expansion of the carbon bed, back-mixing, solid mixing and gas mixing, especially for the delayed bubbling bed and bubbling bed. This indicates that the adopted coupling method is feasible to improve the anode performance of direct carbon solid oxide fuel cell.

Estimation of the Solid Circulation Rate in Circulating Fluidized Bed System Using Adaptive Neuro-Fuzzy Algorithm

“…Due to the decrement in amount of Nitrogen Oxide, Sulphur Oxide, and low combustion temperature, the gasifier performance would be improved; also the size of boiler would become smaller. Shape is also an important factor which is beneficial for FBC [16][17][18][19][20]. FBCs are categorized based on fluidized bed; some of them are fixed bed combustor, Atmospheric/Bubbling bed combustion, Turbulent FBC, Fast bed/Circulating FBC, Transport FBC.…”