The Feasibility Study of Perovskite Oxygen Carriers for Chemical Looping Combustion

摘要

As the issue of global warming is getting bigger, it attracts more attention every day. Statistics show the exponentially increase of the emission of greenhouse gases to the atmosphere. Carbon dioxide (CO2) is one of the most important greenhouse gases that remains in the atmosphere for thousands of years because CO2 is a product of the combustion of fossil fuels as a main source of energy. To reduce the amount of CO2 emitted into the atmosphere, Chemical-looping combustion (CLC) as a new energy efficient technology for capturing produced CO2 has been studied in this research. In this project, extended time reactor tests were investigated using a previously designed and synthesized oxygen carrier by Dr. Nadarajah's research group at The University of Toledo. Reactor tests were carried out for 150 cycles of oxidation and reduction in a fluidized bed reactor, with properties of the oxygen carrier tested before and after 150 cycles. The same test was done on CaMnO3-a for 100 cycles and the results were compared. The result showed complete combustion, no agglomeration and improved oxygen capacity after 150 cycles for Ca0.9Sr 0.1Mn0.9Fe0.1O3-delta. CSMF, which is a modified form of CaMnO3, did not show any issues relating to stability in extended time reactor tests unlike CaMnO3, thus CSMF can be a good candidate to be tested in industrial units.;Moreover, a comparison between the cost of 1kW of electricity produced from CLC plant ($0.20/kW) and solar cells ($3.7/Watt) has been provided in this research.;Perovskite hollow fiber membrane is another application for perovskite materials. Formulation of perovskite paste was successfully optimized to produce perovskite hollow fibers by using an industrial extruder.;Doping CSMF with Ba can increase the size and in turn oxygen capacity of perovskite structure. CSBMF with two different ratio of barium was synthesized and characterized by XRD, SEM, EDS and TGA. The results showed that the oxygen capacity of CSBMF particles is less than CSMF particles.