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Title: Experimental evaluations of solid-fueled pressurized chemical looping combustion – The effects of pressure, solid fuel and iron-based oxygen carriers

Authors:
; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1397075
Grant/Contract Number:
FE0025098
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Applied Energy
Additional Journal Information:
Journal Volume: 195; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-10-04 16:05:55; Journal ID: ISSN 0306-2619
Publisher:
Elsevier
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Chen, Liangyong, Kong, Liang, Bao, Jinhua, Combs, Megan, Nikolic, Heather S., Fan, Zhen, and Liu, Kunlei. Experimental evaluations of solid-fueled pressurized chemical looping combustion – The effects of pressure, solid fuel and iron-based oxygen carriers. United Kingdom: N. p., 2017. Web. doi:10.1016/j.apenergy.2017.03.085.
Chen, Liangyong, Kong, Liang, Bao, Jinhua, Combs, Megan, Nikolic, Heather S., Fan, Zhen, & Liu, Kunlei. Experimental evaluations of solid-fueled pressurized chemical looping combustion – The effects of pressure, solid fuel and iron-based oxygen carriers. United Kingdom. doi:10.1016/j.apenergy.2017.03.085.
Chen, Liangyong, Kong, Liang, Bao, Jinhua, Combs, Megan, Nikolic, Heather S., Fan, Zhen, and Liu, Kunlei. Thu . "Experimental evaluations of solid-fueled pressurized chemical looping combustion – The effects of pressure, solid fuel and iron-based oxygen carriers". United Kingdom. doi:10.1016/j.apenergy.2017.03.085.
@article{osti_1397075,
title = {Experimental evaluations of solid-fueled pressurized chemical looping combustion – The effects of pressure, solid fuel and iron-based oxygen carriers},
author = {Chen, Liangyong and Kong, Liang and Bao, Jinhua and Combs, Megan and Nikolic, Heather S. and Fan, Zhen and Liu, Kunlei},
abstractNote = {},
doi = {10.1016/j.apenergy.2017.03.085},
journal = {Applied Energy},
number = C,
volume = 195,
place = {United Kingdom},
year = {Thu Jun 01 00:00:00 EDT 2017},
month = {Thu Jun 01 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.apenergy.2017.03.085

Citation Metrics:
Cited by: 2works
Citation information provided by
Web of Science

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  • This work analyzes the main characteristics related to the chemical looping combustion (CLC) process necessary to use the syngas obtained in an integrated gasification combined cycle (IGCC) power plant. The kinetics of reduction with H{sub 2} and CO and oxidation with O{sub 2} of three high-reactivity oxygen carriers used in the CLC system have been determined in a thermogravimetric analyzer at atmospheric pressure. The iron- and nickel-based oxygen carriers were prepared by freeze-granulation, and the copper-based oxygen carrier was prepared by impregnation. The changing grain size model (CGSM) was used for the kinetic determination, assuming spherical grains for the freeze-granulatedmore » particles containing iron and nickel and a platelike geometry for the reacting surface of the copper-based impregnated particles. The dependence of the reaction rates on temperature was low, with the activation energy values varying from 14 to 33 kJ mol{sup -1} for the reduction and 7 to 15 kJ mol{sup -1} for the oxidation. The reaction order depended on the reacting gas and oxygen carrier, with values ranging from 0.25 to 1. However, an increase in the operating pressure for the IGCC + CLC system increases the thermal efficiency of the process, and the CO{sub 2} is recovered as a high pressure gas, decreasing the energy demand for further compression. The effect of pressure on the behavior of the oxygen carriers has been analyzed in a pressurized thermogravimetric analyzer at 1073 K and pressures up to 30 atm. It has been found that an increase in total pressure has a negative effect on the reaction rates of all the oxygen carriers. Moreover, the use of the CGSM with the kinetic parameters obtained at atmospheric pressure predicted higher reaction rates than those experimentally obtained at higher pressures, and therefore, the kinetic parameters necessary to design pressurized CLC plants must be determined at the operating pressure. 34 refs., 8 figs., 2 tabs.« less
  • Chemical looping combustion (CLC) is an emerging technology for clean energy production from fuels. CLC produces sequestration-ready CO{sub 2}-streams without a significant energy penalty. Development of efficient oxygen carriers is essential to successfully operate a CLC system. Copper and iron oxides are promising candidates for CLC. Copper oxide possesses high reactivity but it has issues with particle agglomeration due to its low melting point. Even though iron oxide is an inexpensive oxygen carrier it has a slower reactivity. In this study, mixed metal oxide carriers containing iron and copper oxides were evaluated for coal and methane CLC. The components ofmore » CuO and Fe{sub 2}O{sub 3} were optimized to obtain good reactivity while maintaining physical and chemical stability during cyclic reactions for methane-CLC and solid-fuel CLC. Compared with single metal oxygen carriers, the optimized Cu–Fe mixed oxide oxygen carriers demonstrated high reaction rate, better combustion conversion, greater oxygen usage and improved physical stability. Thermodynamic calculations, XRD, TGA, flow reactor studies and TPR experiments suggested that there is a strong interaction between CuO and Fe{sub 2}O{sub 3} contributing to a synergistic effect during CLC reactions. The amount of oxygen release of the mixed oxide carrier in the absence of a fuel was similar to that of the single metal oxides. However, in the presence of fuels, the oxygen consumption and the reaction profiles of the mixed oxide carriers were significantly better than that of the single metal oxides. The nature of the fuel not only influenced the reactivity, but also the final reduction status of the oxygen carriers during chemical looping combustion. Cu oxide of the mixed oxide was fully reduced metallic copper with both coal and methane. Fe oxide of the mixed oxide was fully reduced Fe metal with methane but it was reduced to only FeO with coal. Possible mechanisms of how the presence of CuO enhances the reduction of Fe{sub 2}O{sub 3} are discussed.« less
  • Chemical-looping combustion (CLC) has been suggested among the best alternatives to reduce the economic cost of CO{sub 2} capture using fuel gas because CO{sub 2} is inherently separated in the process. For gaseous fuels, natural gas, refinery gas, or syngas from coal gasification can be used. These fuels may contain different amounts of sulfur compounds, such as H{sub 2}S and COS. An experimental investigation of the fate of sulfur during CH{sub 4} combustion in a 500 W{sub th} CLC prototype using a Ni-based oxygen carrier has been carried out. The effect on the oxygen carrier behavior and combustion efficiency ofmore » several operating conditions such as temperature and H{sub 2}S concentration has been analyzed. Nickel sulfide, Ni3S{sub 2}, was formed at all operating conditions in the fuel reactor, which produced an oxygen carrier deactivation and lower combustion efficiencies. However, the oxygen carrier recovered their initial reactivity after certain time without sulfur addition. The sulfides were transported to the air reactor where SO{sub 2} was produced as final gas product. Agglomeration problems derived from the sulfides formation were never detected during continuous operation. Considering both operational and environmental aspects, fuels with sulfur contents below 100 vppm H{sub 2}S seem to be adequate to be used in an industrial CLC plant.« less
  • Chemical-looping combustion (CLC) is a new combustion technology with inherent separation of CO{sub 2}. Most of the previous investigations on CLC of solid fuels were conducted under atmospheric pressure. A pressurized CLC combined cycle (PCLC-CC) system is proposed as a promising coal combustion technology with potential higher system efficiency, higher fuel conversion, and lower cost for CO{sub 2} sequestration. In this study pressurized CLC of coal with Companhia Valedo Rio Doce (CVRD) iron ore was investigated in a laboratory fixed bed reactor. CVRD iron ore particles were exposed alternately to reduction by 0.4 g of Chinese Xuzhou bituminous coal gasifiedmore » with 87.2% steam/N{sub 2} mixture and oxidation with 5% O{sub 2} in N{sub 2} at 970 C. The operating pressure was varied between 0.1 MPa and 0.6 MPa. First, control experiments of steam coal gasification over quartz sand were performed. H{sub 2} and CO{sub 2} are the major components of the gasification products, and the operating pressure influences the gas composition. Higher concentrations of CO{sub 2} and lower fractions of CO, CH{sub 4}, and H{sub 2} during the reduction process with CVRD iron ore was achieved under higher pressures. The effects of pressure on the coal gasification rate in the presence of the oxygen carrier were different for pyrolysis and char gasification. The pressurized condition suppresses the initial coal pyrolysis process while it also enhances coal char gasification and reduction with iron ore in steam, and thus improves the overall reaction rate of CLC. The oxidation rates and variation of oxygen carrier conversion are higher at elevated pressures reflecting higher reduction level in the previous reduction period. Scanning electron microscope and energy-dispersive X-ray spectroscopy (SEM-EDX) analyses show that particles become porous after experiments but maintain structure and size after several cycles. Agglomeration was not observed in this study. An EDX analysis demonstrates that there is very little coal ash deposited on the oxygen carrier particles but no appreciable crystalline phases change as verified by X-ray diffraction (XRD) analysis. Overall, the limited pressurized CLC experiments carried out in the present work suggest that PCLC of coal is promising and further investigations are necessary. (author)« less
  • The disclosure provides an oxygen carrier for a chemical looping cycle, such as the chemical looping combustion of solid carbonaceous fuels, such as coal, coke, coal and biomass char, and the like. The oxygen carrier is comprised of at least 24 weight % (wt %) CuO, at least 10 wt % Fe2O3, and an inert support, and is typically a calcine. The oxygen carrier exhibits a CuO crystalline structure and an absence of iron oxide crystalline structures under XRD crystallography, and provides an improved and sustained combustion reactivity in the temperature range of 600.degree. C.-1000.degree. C. particularly for solid fuelsmore » such as carbon and coal.« less