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Synthesis and Evaluation of Nanomaterials for Combustion Technologies

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Fossil fuels are expected to be responsible for 78% of the world’s total energy production in 2040 despite the growing efforts on expanding renewable energy sources. Along with California's efforts to transition to sustainable energy production, the use of hydrogen gas as a clean fuel has recently gained attention. The first part of this work focuses on a new strategy for combating anthropogenic climate change by blending hydrogen with natural gas to be used as fuel in stationary power plants and studies the effect of hydrogen blending on the performance of the selective catalytic reduction (SCR) unit that is used to reduce emissions of nitrogen oxides (NOx). A commercial SCR catalyst was tested under different flue gas compositions to simulate different stationary power applications. The effects of hydrogen content, equivalence ratio, reaction temperature, and the presence of sulfur dioxide (SO2) on the SCR process were investigated. The results show that the leaner the combustion process, the higher the NOx conversion. High hydrogen content does not have a significant effect on NOx conversion. Increasing the temperature from 350°C to 400°C slightly improves the performance of the catalyst. The presence of SO2 up to 100ppm has a small effect on the performance of the SCR catalyst. However, increasing the sulfur content to 500ppm decreases the performance of the catalyst, with a higher decrease for the lean conditions.Chemical-looping combustion (CLC), a relatively new approach as a carbon capture and storage (CCS) technology, has emerged as a promising alternative to traditional CCS technologies. The main goal of the second part of this work is to develop a novel oxygen carrier to be used for the chemical looping with oxygen uncoupling (CLOU) process. One of the main challenges of the CLOU process is to find a suitable oxygen carrier, which can operate under the combustion conditions and tolerate many oxidation-reduction cycles. One of the strategies to avoid sintering of the materials due to high temperature is to encapsulate the oxygen carrier with a support material. In a core-shell structure, the active sites as the core are covered with a layer of shell, which provides stability for the oxygen carrier. Core-shell material are well implemented and studied in catalysis field; however, it is still a novel approach for synthesis of oxygen carriers. In this work, novel core-shell structured CuO-based oxygen carriers were synthesized with two different support materials, CeO2 and SiO2. Synthesis parameters were optimized using design of experiments to obtain the optimum amount of ceria loaded on the CuO@CeO2. The new core-shell oxygen carriers were found to have nearly the same oxygen release capacity as the composite materials. These oxygen carriers will be tested under chemical looping conditions in the future.

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This item is under embargo until December 1, 2025.