Modeling of the chemical-looping combustion of methane using a Cu-based oxygen-carrier

Journal Article · Mon Mar 15 00:00:00 EDT 2010 · Combustion and Flame

DOI:https://doi.org/10.1016/J.COMBUSTFLAME.2009.10.010· OSTI ID:21285645

Abad, Alberto; Adanez, Juan; Garcia-Labiano, Francisco; de Diego, Luis F; Gayan, Pilar ^[1]

---

1. Instituto de Carboquimica (CSIC), Department of Energy and Environment, Miguel Luesma Castan 4, 50018 Zaragoza (Spain)

A mathematical model for a bubbling fluidized bed has been developed to simulate the performance of the fuel-reactor in chemical-looping combustion (CLC) systems. This model considers both the fluid dynamic of the fluidized bed and freeboard and the kinetics of reduction of the oxygen-carrier, here CuO impregnated on alumina. The main outputs of the model are the conversion of the carrier and the gas composition at the reactor exit, the axial profiles of gas concentrations and the fluid dynamical structure of the reactor. The model was validated using measurements when burning CH{sub 4} in a 10 kW{sub th} prototype using a Cu-based oxygen-carrier. The influence of the circulation rate of solids, the load of fuel gas, the reactor temperature and size of the oxygen-carrier particles were analyzed. Combustion efficiencies predicted by the model showed a good agreement with measurements. Having validated the model, the implications for designing and optimizing a fuel-reactor were as follows. The inventory of solids for a high conversion of the fuel was sensitive to the reactor's temperature, the solids' circulation rate and the extent to which the solids entering to the reactor had been regenerated. The optimal ratio of oxygen-carrier to fuel was found to be 1.7-4 for the Cu-based oxygen-carrier used here. In this range, the inventory of solids to obtain a combustion efficiency of 99.9% at 1073 K was less than 130 kg/MW{sub th}. In addition, the model's results were very sensitive to the resistance to gas diffusing between the emulsion and bubble phases in the bed, to the decay of solids' concentration in the freeboard and to the efficiency contact between gas and solids in the freeboard. Thus, a simplified model, ignoring any restriction to gas and solids contacting each other, will under-predict the inventory of solids by a factor of 2-10. (author)

• OSTI ID: 21285645
• Journal Information: Combustion and Flame, Vol. 157, Issue 3; Other Information: Elsevier Ltd. All rights reserved; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
NATURAL GAS
METHANE
COMBUSTION
OXYGEN
COPPER OXIDES
SOLIDS
CARRIERS
FLUIDIZED BEDS
ALUMINIUM OXIDES
EFFICIENCY
ACCURACY
INVENTORIES
SIMULATION
CONVERSION
REDUCTION
MATHEMATICAL MODELS
BUBBLES
COMBUSTION KINETICS
OPTIMIZATION
PARTICLE SIZE
PERFORMANCE
CHEMICAL COMPOSITION
COMBUSTORS
TEMPERATURE DEPENDENCE
DESIGN
COPPER
TEMPERATURE RANGE 1000-4000 K
SENSITIVITY ANALYSIS
Chemical-looping combustion