In a chemical-looping combustor (CLC), gaseous fuel is oxidized by metal oxide particle, e.g. oxygen carrier, in a reduction reactor (combustor), and the greenhouse gas CO₂ is separated from the exhaust gases during the combustion. In this study, NiO/bentonite particle was examined on the basis of reduction reactivity, carbon deposition during reduction, and NO_x formation during oxidation. Reactivity data for NiO/bentonite particle with methane and air were presented and discussed. During the reduction period, most of the CH₄ are converted to CO₂ with small formation of CO. Reduction reactivity (duration of reduction) of the NiO/bentonite particle increased with temperature, but at higher temperature, it is somewhat decreased. The NiO/bentonite particle tested showed no agglomeration or breakage up to 900 ℃, but at 1,000 ℃, sintering took place and lumps of particles were formed. Solid carbon was deposited on the oxygen carrier during high conversion region of reduction, i.e., during the end of reduction. It was found that the appropriate temperature for the NiO/bentonite particle is 900 ℃ for carbon deposition, reaction rate, and duration of reduction. We observed experimentally that NO, NO₂, and N₂O gases are not generated during oxidation.

Chemical-Looping Combustion Fixed Bed Oxygen Carrier Particle CO₂ NO_x

Anheden M, Svedeverg G, "Chemical-Looping Combustion in Combination with Integrated Coal Gasification," IECEC '96, 31st Intersociety Energy Converstion Engineering Conference, Washington D.C., U.S.A., 4, 2045 (1996)
Anheden M, Svedberg G, Energy Conv. Manag., 39(16-18), 1967 (1998) 
Copeland RJ, Alptekin G, Cesario M, Gebhard S, Gershanovich Y, "A Novel CO2 Separation System," The 8th International Symposium on Transport and Dynamics of Rotating Machinery (ISROMAC-8), Honolulu, Hawaii, March 26-30 (2000)
Gallardo S, Aida T, Niiyama H, Korean J. Chem. Eng., 15(5), 480 (1998)
Herzog H, Drake E, "Long-Term Advanced CO2 Capture Options," IEA/93/0E6, IEA Greenhouse Gas R&D Programme, Cheltenham, UK (1993)
Herzog H, Drake E, Adams E, "CO2 Capture, REuse, and Storage Technologies for Mitigating Global Climate Change," White Paper Final Report, Order No. DE-AF22-96PC01257, US DOE (1997)
IEA Greenhouse Gas R&D Programme Report, "Carbon Dioxide Capture from the Power Stations," available on http://www.ieagreen.org.uk/sr2p.htm.
IEA Greenhouse Gas R&D Programme Report, "Greenhouse Gas Emissions from Power Stations," available on http://www.ieagreen.org.uk/sr1p.htm.
Ishida M, Jin HG, Okamoto T, Energy Fuels, 12(2), 223 (1998) 
Jin H, Okamoto T, Ishida M, Energy Fuels, 12(6), 1272 (1998) 
Lee DK, Ihm SK, Korean J. Chem. Eng., 6(1), 41 (1989)
Mimura T, Simayoshi H, Suda T, Iijima M, Mituoka S, Energy Conv. Manag., 38, S57 (1997)
Podolski WF, Swift WM, Miller SA, "Air Emissions from Pressurized Fluidized Bed Combustor," Pressurized Fluidized Bed Combustion, Cuenca, M.A. and Anthony, E.J. eds., Chapman & Hall, London (1995)
Richter HJ, Knoche KF, "Reversibility of Combustion Process," ACS Symposium Series, R.A. Gaggioli, ed., Washington, D.C., 235, 71 (1983)
Ryu HJ, Bae DH, Han KH, Lee SY, Jin GT, Choi JH, Korean J. Chem. Eng., 18(6), 831 (2001)
Ryu HJ, "CO2-NOx free Chemical-Looping Combustion Technology," KOSEN 21 (The Global Network of Korean Scientists and Engineers) Advanced Technology Report, in print (2003)
Ryu HJ, Lim NY, Bae DH, Jin GT, Korean J. Chem. Eng., 20(1), 157 (2003)
Wolf J, Anheden M, Yan J, "Performance Analysis of Combined Cycles with Chemical Looping Combustion for CO2 Capture," Proceedings of 18th Pittsburg Coal Conference, December 3-7, Newcastle, NSW, Australia, Session 23, CD-ROM (2001)
Yoon KJ, Kim EJ, Korean J. Chem. Eng., 12(2), 221 (1995)