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TGA and kinetic modelling of Co, Mn and Cu oxides for chemical looping gasification (CLG)
Author(s) -
Aghabararnejad Milad,
Patience Gregory S.,
Chaouki Jamal
Publication year - 2014
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.22046
Subject(s) - oxygen , manganese , cobalt , chemical looping combustion , chemistry , copper , gravimetric analysis , inorganic chemistry , analytical chemistry (journal) , environmental chemistry , organic chemistry
Oxygen carriers for biomass gasification are capable of absorbing oxygen from air and desorbing it in the gasifier. Based on thermodynamic equilibrium, copper, manganese, and cobalt oxides have the highest oxygen release capacities among the different oxygen carriers. These oxygen carriers were deposited on alumina via incipient wetness impregnation. The weight loss of the CuO–Cu 2 O carrier, as measured in a thermo‐gravimetric analyzer, was 10 % while it was 7 % for the Co 3 O 4 –CoO couple and only 3 % for the Mn 2 O 3 –Mn 3 O 4 couple. The optimum operating temperature for the CuO oxygen carrier was 100 °C higher compared to the other two at 950 °C. A modified nuclei growth model (MNG) characterizes the weight loss/gain during the reduction‐oxidation cycles. The reduction rate is 3 times higher at 875 °C compared to 825 °C while the oxidation rate decreases more than 10 times. The CuO carrier surface area decreased by 70 %, while it was 30 % and 60 % in the Co 3 O 4 and Mn 2 O 3 carriers, respectively. Cobalt has a lower tendency to sinter at high temperature compared to either copper or manganese and has a higher oxygen transport capacity and oxidation‐reduction rates. Therefore, despite its higher cost and toxicity, it might be considered as a potential oxygen carrier especially for solid fuel gasification.