System efficiency analysis of dual interconnected bubbling fluidized bed reactors for solar fuel production

Abstract

Chemical looping syngas production is a two-step syngas fuel production process that produces CO and H2. The process is composed of two fluidized bed reactors (oxidation reaction and reduction reactor), oxygen carriers (metal oxides) circulating between the two reactors. A comprehensive model is developed to simulate the chemical looping water and carbon dioxide splitting in a dual fluidized bed reactors interconnected with redox cycling between these two reactors through metal oxides (non-stoichiometric ceria). An extensive FORTRAN subroutine is developed and hooked into Aspen plus V8.8 to appropriately model the complexities of the bubbling fluidized bed reactor including the reaction kinetics. The model developed has been validated for its hydrodynamics and kinetics level and individual correlation was quantified for its validity. The reduction reactor is supplied with the solar energy that temperature above 1300oC is varied up to 1550oC. The heat to attain this high temperature is achieved with solar beam down tower. The oxidation reactor is supplied with a mixture of CO2 and H2O with different mixture composition combining 60% and remaining N2. The oxidation reactor temperature is varied between 700-1000oC to identify the maximum efficiency achieved. It is found that the maximum efficiency achieved is 67% corresponds to highest temperature difference between the reactors.