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Title: Chemical-looping combustion of simulated synthesis gas using nickel oxide oxygen carrier supported on bentonite

Abstract

Chemical-looping combustion (CLC) is a combustion technology for clean and efficient utilization of fossil fuels for energy production. This process which produces sequestration ready CO2 systems is a promising technology to be utilized with coal gasification systems. In the present work, chemical-looping combustion has been studied with an oxygen carrier, NiO/bentonite (60 wt % NiO) for the gasification systems utilizing simulated synthesis gas. Global reaction rates of reduction and oxidation as a function of conversion were calculated for oxidation-reduction cycles utilizing the thermogravimetric analysis (TGA) data on multicycle tests conducted with NiO/bentonite at atmospheric pressure between 700 and 900 °C. The rate of reduction increased slightly with an increase in temperature, while the rate of oxidation decreased at 900 °C. The effect of particle size of the oxygen carrier on CLC was studied for the particle size between 20 and 200 mesh. The rates of reactions depended on the particle size of the oxygen carrier. The smaller the particle size, the higher the reaction rates. The multicycle CLC tests conducted in a high-pressure flow reactor showed stable reactivity for the production of CO2 from fuel gas at 800 and 900 °C and full consumption of hydrogen during the reaction. Themore » data from a one cycle test on the effect of the pressure on the performance with NiO/bentonite utilizing the tapered element oscillating microbalance (TEOM) showed a positive effect of the pressure on the global rates of reduction-oxidation reactions at higher fractional conversions. The X-ray diffraction (XRD) analysis confirmed the presence of the NiO phase in NiO/bentonite with the oxidized sample in the highpressure reactor and Ni phase with the reduced sample. The presence of a small amount of NiO in the reduced sample detected by X-ray photoelectron spectroscopy (XPS) may be due to its exposure to air during sample transfer from the reactor to XPS. Scanning electron microscopy (SEM) analysis showed no significant changes in morphology of NiO/bentonite reacted in the temperature range 700-800 °C in an atmospheric TGA for 10 oxidation-reduction cycles, but some loss of surface area and porosity was observed at 900 °C. This effect was found to be greater with increase in the particle size of the oxygen carrier.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR (United States)
Sponsoring Org.:
USDOE - Office of Fossil Energy (FE)
OSTI Identifier:
915399
Report Number(s):
DOE/NETL-IR-2007-136
Journal ID: ISSN 0887-0624
DOE Contract Number:  
None cited
Resource Type:
Journal Article
Journal Name:
Energy and Fuels
Additional Journal Information:
Journal Volume: 21; Journal Issue: 3; Journal ID: ISSN 0887-0624
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
20 FOSSIL-FUELED POWER PLANTS; chemical looping combustion; fossil fuels; carbon dioxide sequestratioin; coal gasification

Citation Formats

Siriwardane, R V, Chaudhari, K, Poston, J A, Zinn, A, Simonyi, T, and Robinson, C. Chemical-looping combustion of simulated synthesis gas using nickel oxide oxygen carrier supported on bentonite. United States: N. p., 2007. Web. doi:10.1021/ef0604947.
Siriwardane, R V, Chaudhari, K, Poston, J A, Zinn, A, Simonyi, T, & Robinson, C. Chemical-looping combustion of simulated synthesis gas using nickel oxide oxygen carrier supported on bentonite. United States. https://doi.org/10.1021/ef0604947
Siriwardane, R V, Chaudhari, K, Poston, J A, Zinn, A, Simonyi, T, and Robinson, C. Tue . "Chemical-looping combustion of simulated synthesis gas using nickel oxide oxygen carrier supported on bentonite". United States. https://doi.org/10.1021/ef0604947.
@article{osti_915399,
title = {Chemical-looping combustion of simulated synthesis gas using nickel oxide oxygen carrier supported on bentonite},
author = {Siriwardane, R V and Chaudhari, K and Poston, J A and Zinn, A and Simonyi, T and Robinson, C},
abstractNote = {Chemical-looping combustion (CLC) is a combustion technology for clean and efficient utilization of fossil fuels for energy production. This process which produces sequestration ready CO2 systems is a promising technology to be utilized with coal gasification systems. In the present work, chemical-looping combustion has been studied with an oxygen carrier, NiO/bentonite (60 wt % NiO) for the gasification systems utilizing simulated synthesis gas. Global reaction rates of reduction and oxidation as a function of conversion were calculated for oxidation-reduction cycles utilizing the thermogravimetric analysis (TGA) data on multicycle tests conducted with NiO/bentonite at atmospheric pressure between 700 and 900 °C. The rate of reduction increased slightly with an increase in temperature, while the rate of oxidation decreased at 900 °C. The effect of particle size of the oxygen carrier on CLC was studied for the particle size between 20 and 200 mesh. The rates of reactions depended on the particle size of the oxygen carrier. The smaller the particle size, the higher the reaction rates. The multicycle CLC tests conducted in a high-pressure flow reactor showed stable reactivity for the production of CO2 from fuel gas at 800 and 900 °C and full consumption of hydrogen during the reaction. The data from a one cycle test on the effect of the pressure on the performance with NiO/bentonite utilizing the tapered element oscillating microbalance (TEOM) showed a positive effect of the pressure on the global rates of reduction-oxidation reactions at higher fractional conversions. The X-ray diffraction (XRD) analysis confirmed the presence of the NiO phase in NiO/bentonite with the oxidized sample in the highpressure reactor and Ni phase with the reduced sample. The presence of a small amount of NiO in the reduced sample detected by X-ray photoelectron spectroscopy (XPS) may be due to its exposure to air during sample transfer from the reactor to XPS. Scanning electron microscopy (SEM) analysis showed no significant changes in morphology of NiO/bentonite reacted in the temperature range 700-800 °C in an atmospheric TGA for 10 oxidation-reduction cycles, but some loss of surface area and porosity was observed at 900 °C. This effect was found to be greater with increase in the particle size of the oxygen carrier.},
doi = {10.1021/ef0604947},
url = {https://www.osti.gov/biblio/915399}, journal = {Energy and Fuels},
issn = {0887-0624},
number = 3,
volume = 21,
place = {United States},
year = {2007},
month = {5}
}