Effects of Carbon on the Rates of Reduction in Iron-based Chemical Looping
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Publisher:The Ohio State University
Series/Report no.:The Ohio State University. Department of Chemical and Biomolecular Engineering Honors Theses; 2010
The availability and low cost of coal and natural gas make them favorable fuels for energy conversion processes. However, the combustion of carbon-based fuels inevitably results in production of CO2. To avert climate change and comply with likely future regulations, the CO2 byproduct must be efficiently captured. Unfortunately, existing carbon capture methods result in up to a 2-fold increase in capital and operating costs. Chemical looping technologies are a group of processes that can separate the CO2 stream in-situ by utilizing iron oxide composite particles as oxygen carriers. The process allows for efficient total carbon capture, therefore ensuring a sustainable future for carbon-fueled hydrogen production. The objective of this study was to explore the effect the presence of carbon has on the reduction rates of 11 iron oxide-based particle compositions. The 11 particles have been isolated from previous recyclability tests of 126 different particle compositions. Faster reduction rates allows for a reduction in capital costs in scale-up design and a smaller oxygen carrier requirement, both of which are required to ensure the success of CDCL. The experiments use TGA to determine the rate of reduction at 900°C and 1 atmosphere in a methane (CH4) environment. T-7, T-2 and T-3 compositions have the fastest rate of reduction. The addition of CeO2 and ZrO2 based promoters are shown to enhance these rates even more and reduce the rate of carbon deposition. The use of promoters needs to be explored more extensively to find the optimal composition for an acceptable trade-off in cost for performance.
Distinction in Chemical Engineering
Undergraduate Engineering Honors Research