Modeling the Chemical Looping Reforming Process Operated in a Circulating Fluidized Bed Reactor Consisting of Two Bubbling Bed Units: Model Validation

A transient one-dimensional model is developed for simulation of the chemical looping reforming process in a circulating fluidized bed (CFB). A CFB reactor model consisting of two connected bubbling bed units, namely the fuel reactor (FR) and the air reactor (AR), is proposed, and the simulated results are validated by comparison with experimental data available in the literature. Three cases with different oxygen-carrier-to-fuel ratios are simulated until the equilibrium concentrations are established in the solid phase. The hydrogen conversion and oxygen carrier conversion results from the simulations are then compared with experimental data from the literature, showing that the numerical results are in fair agreement with the experimental results. Model validation against experimental data of the process performance is of paramount importance for future process design and optimization of chemical looping systems via numerical modeling and simulation

Modeling and Simulation of Chemical Looping Combustion Using a Copper-Based Oxygen Carrier in a Double-Loop Circulating Fluidized Bed Reactor System

In this work, a computational fluid dynamics simulator has been developed for a novel double-loop circulating fluidized bed reactor which is used for a chemical looping combustion process. The simulator is implemented in an in-house code including the kinetic theory of granular flow and reaction models. Methane is used as fuel, and copper oxide-based particles are used as oxygen carrier. The process is configured with an air reactor and a fuel reactor. The two reactors are modeled and solved by a sequential approach. The connection between the two reactors is realized through time-dependent inlet and outlet boundary conditions. The model is validated with the experimental data obtained in the current work. At a thermal input of 100 kW, a methane conversion of 98% was achieved. For the cases studied in this work, temperature is the most important factor for the reactor performance, followed by the gas velocity and methane concentration of fuel. The increase of the methane concentration could decrease the methane conversion, which is due to the decrease of specific inventory. As the gas velocity is increased, the residence time and the degree of gas–solid contact decreases, causing a decrease in reactor performance. Besides the effect of the single factor, the combination effect of the gas velocity and methane concentration is also important to the reactor performance