Investigation of chemical looping combustion by solid fuels. 2. redox reaction kinetics and product characterization with coal, biomass, and solid waste as solid fuels and CuO as an oxygen carrier

Journal Article · Sun Oct 15 00:00:00 EDT 2006 · Energy and Fuels

OSTI ID:20813151

Cao, Yan; Casenas, Bianca; Pan, Wei-Ping ^[1]

---

1. Western Kentucky University, Bowling Green, KY (United States). Institute for Combustion Science and Environmental Technology

This paper is the second in a series of two on the investigation of the chemical looping combustion (CLC) of solid fuels. The first paper put forward the concept of the CLC of solid fuels using a circulating fluidized bed as a reactor and Cu-CuO as the oxygen carrier, which was based on an analysis of oxygen transfer capability, reaction enthalpy, and chemical equilibrium. In this second paper, we report the results of the evaluation of the reduction of CuO reduced by solid fuels such as coal and some other 'opportunity' solid fuels. Tests on the reduction of CuO by the selected solid fuels were conducted using simultaneous differential scanning calorimetry and thermogravimetric analysis, which simulates a microreactor. An attached mass spectrometer (MS) was used for the characterization of evolved gaseous products. The X-ray diffractometer (XRD) and scanning electron microscope (SEM) were used for the characterization of the solid residues. Results strongly supported the feasibility of CuO reduction by selected solid fuels. CuO can be fully converted into Cu in a reduction process, either in a direct path by solid fuels, which was verified by MS analysis under a N{sub 2} atmosphere, or in an indirect path by pyrolysis and gasification products of solid fuels in the reducer. No Cu{sub 2}O exists in reducing atmospheres, which was characterized by an XRD analysis and mass balance calculations. No carbon deposit was found on the surface of the reduced Cu, which was characterized by SEM analysis. CuO reduction by solid fuels can start at temperatures as low as approximately 500 C. Tests indicated that the solid fuels with higher reactivity (higher volatile matter) would be desirable for the development of the chemical looping combustion process of solid fuels, such as sub-bituminous Powder River Basin coal and solid waste and biomass. 4 refs., 12 figs., 3 tabs.

• OSTI ID: 20813151
• Journal Information: Energy and Fuels, Vol. 20, Issue 5; Other Information: [e-mail]; ISSN 0887-0624
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
09 BIOMASS FUELS
SOLID FUELS
COAL
COMBUSTION
REDOX REACTIONS
CHEMICAL REACTION KINETICS
BIOMASS
SOLID WASTES
COPPER OXIDES
FLUIDIZED BEDS
CIRCULATING SYSTEMS
DIFFERENTIAL THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
MASS SPECTROSCOPY
X-RAY DIFFRACTION
SCANNING ELECTRON MICROSCOPY
SUBBITUMINOUS COAL