Process modeling aspects of chemical-looping with oxygen uncoupling and chemical-looping combustion for solid fuels

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Title Process modeling aspects of chemical-looping with oxygen uncoupling and chemical-looping combustion for solid fuels
Publication Type dissertation
School or College College of Engineering
Department Chemical Engineering
Author Sahir, Asad Hasan
Date 2013-08
Description Chemical-looping combustion (CLC) is one of the candidate technologies that is currently being explored to reduce the energy penalty associated with capturing CO2 from coal-fired power plants. In CLC, the fuel is burnt in the presence of oxygen supplied by an oxygen carrier circulating between two reactors, instead of atmospheric air. This dissertation investigates the requisite process modeling aspects for CLC for solid carbonaceous fuels, in particular focusing on chemical-looping with oxygen uncoupling (CLOU). In CLOU, gaseous phase oxygen is released by the decomposition of a metal oxide (e.g. CuO) in which the solid fuel burns to form CO2 . This contrasts with CLC, where the solid fuel has to be gasified initially to form syngas which subsequently reacts with the circulating oxygen carrier to form CO2. As a first step, the significance of the Law of Additive Reaction Times in identifying the controlling regime (internal/external mass transfer or chemical reaction) for CLC systems was explored. Two reported experimental studies for copper oxidation reaction in air reactor were reanalyzed. The methodology developed was applied to analyze the CuO decomposition and Cu2O oxidation reaction for CLOU. A rate analysis of the reported bench-scale batch fluidized-bed CLOU experimental data was performed to determine the kinetics of the CuO decomposition, Cu2O oxidation, and petcoke oxidation reactions. The obtained kinetics were subsequently utilized in the development of a fluidized-bed model to evaluate the oxygen and carbon dioxide concentration trends, and the results were validated against independently obtained experimental data reported in literature. The kinetics obtained from the rate analysis of the CLOU reactions were employed in the development of a process model using ASPEN PLUS. Material and energy balance scenarios were developed for solid fuel combustion using a copper-based oxygen carrier for CLOU, and compared with CLC employing an iron-based oxygen carrier. The conceptual design principles will be employed in future investigations on a process development unit based on the CLOU process currently under construction at the University of Utah.
Type Text
Publisher University of Utah
Subject Arbon capture; Chemical-looping combustion (CLC); Chemical-looping with oxygen uncoupling (CLOU); Gas-solid reactions; Process Modeling; Solid fuels
Dissertation Institution University of Utah
Dissertation Name Doctor of Philosophy
Language eng
Rights Management Copyright © Asad Hasan Sahir 2013
Format application/pdf
Format Medium application/pdf
Format Extent 2,889,890 bytes
Identifier etd3/id/2570
ARK ark:/87278/s6kq1995
Setname ir_etd
ID 196146
Reference URL https://collections.lib.utah.edu/ark:/87278/s6kq1995
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