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CaMn 0.875 Ti 0.125 O 3− δ as an Oxygen Carrier for Chemical‐Looping with Oxygen Uncoupling (CLOU)—Solid‐Fuel Testing and Sulfur Interaction
Author(s) -
Sundqvist Sebastian,
Leion Henrik,
Rydén Magnus,
Lyngfelt Anders,
Mattisson Tobias
Publication year - 2013
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201300007
Subject(s) - chemical looping combustion , oxidizing agent , solid fuel , oxygen , petroleum coke , chemistry , fluidized bed , coal , nitrogen , chemical engineering , waste management , materials science , analytical chemistry (journal) , combustion , chromatography , organic chemistry , engineering
Particles of the perovskite material CaMn 0.875 Ti 0.125 O 3− δ have been examined as an oxygen‐carrier material for chemical‐looping with oxygen uncoupling (CLOU). The aim of the work has been to determine the effect of the fuel‐to‐bed mass ratio for oxidizing solid fuels, and to determine the influence of SO 2 on the reactivity with fuel. Two solid fuels have been used: a Mexican petroleum coke and a Colombian coal. The oxygen‐carrier material used in this study was CaMn 0.875 Ti 0.125 O 3− δ and was developed and manufactured by the Norwegian research institute SINTEF. The experiments were conducted in a discontinuous quartz glass batch fluidized‐bed reactor with an inner diameter of 10 mm. The particle bed rests on a porous plate, and thermocouples 5 mm under and 10 mm above the plate were used for measuring the temperature. In the oxidation phase a flow of 1000 mL min −1 with 5 % oxygen in nitrogen was used. During the solid fuel experiments the bed was fluidized with 600 mL min −1 nitrogen and 0.1 g of solid fuel added to the reactor from the top. In the experiments with gaseous fuels the bed was fluidized with 900 mL min −1 total flow, consisting of 450 mL min −1 CH 4 and 450 mL min −1 with 0.25–0.5 % SO 2 in nitrogen. It was found that the Colombian coal was oxidized considerably faster than the petroleum coke, and this is unexpected because the kinetics for O 2 release from the oxygen carrier were expected to determine conversion rate rather than the reactivity of the fuels. The overall rate of conversion increased for experiments with larger bed mass as an expected result. The SO 2 had a negative effect on the reactivity of the oxygen carrier, likely because of formation of CaSO 4 .