Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 16 of 16 for “"Pre-Combustion"”.
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Reducing emissions of a large bore two stroke cycle engine using a natural gas and hydrogen mixture
… formation is primarily a function of in-cylinder combustion temperatures. A challenge for engine researchers is to identify methods to lower combustion temperatures while maintaining complete combustion. Blending hydrogen into an engine's fuel can lower in-cylinder combustion temperatures and …
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Analysis of Biomass/Coal Co-Gasification for Integrated Gasification Combined Cycle (IGCC) Systems with Carbon Capture
… types of CCS, including sweet- and sour-shift pre-combustion and post-combustion.</p> <p>Using the software, Thermoflow®, this study shows that utilizing biomass with coal up to 50% (wt.) can improve the efficiency, and reduce emissions: even making the plant carbon-negative when CCS is used. …
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CFD Modelling of the Mixture Preparation in a Modern Gasoline Direct Injection Engine and Correlations with Experimental PN Emissions
… is carried out to reveal the connections between pre-combustion mixture indicators and PN emissions. Firstly, a novel calibration methodology is introduced to accurately predict the widely used characteristics of the high-pressure fuel spray. The methodology utilised the Siemens STAR-CD 3D CFD …
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Autoignition and emission characteristics of gaseous fuel direct-injection compression-ignition combustion
… of natural gas direct-injection compression-ignition combustion, the effects of key operating parameters (including injection pressure, injection duration, and pre-combustion temperature) and gaseous fuel composition(including the effects of ethane, hydrogen and nitrogen addition) …
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Analysis and optimization of the Graz cycle : a coal fired power generation scheme with near-zero carbon dioxide emissions
… carbon dioxide into the atmosphere through the combustion of fossil fuels in power generation plants. With mounting evidence that this carbon dioxide is a leading cause of global warming and with energy demand exploding, it is time to seek out realistic power production methods that do not …
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CFD Modelling of Down-Sized GDI Engines: Fuel Injection, In-Cylinder Phenomena and Correlation to Engine-Out PN Emissions
… It does that through the development of a comprehensive 3D-CFD in-cylinder modelling tool that enables a robust and accurate insight into the pre-combustion mechanisms potentially leading to PM formation. The results presented refer to standard gasoline fuel, but remain fully relevant to …
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Process and Reactor Level Simulations of Calcium Looping Combustion
… is used to validate the process model for both pre-combustion CaL and post-combustion CaL; it agrees well with the experimental data and simulation results available in the literature. The simulation shows an increasing marginal energy penalty associated with an increase in the carbon capture …
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Strategies for demonstration and early deployment of carbon capture and storage : a technical and economic assessment of capture percentage
… plant performance, and project economics that represent challenges for the first movers who implement the technology. This work finds that capturing only part of the emissions (i.e., partial capture) can facilitate implementation compared to full capture. Partial capture is easier to implement …
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Estimation of the In-Cylinder Air/Fuel Ratio of an Internal Combustion Engine by the Use of Pressure Sensors
This thesis investigates the use of cylinder pressure measurements for estimation of the in-cylinder air/fuel ratio in a spark ignited internal combustion engine. An estimation model which uses the net heat release profile for estimating the cylinder air/fuel ratio of a spark ignition engine is …
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Thermodynamics of ionic liquid solvents in gas purification and exfoliation mechanisms: molecular dynamics simulation and Monte Carlo calculations
… study, I modeled CO2 separation during typical pre-combustion and post-combustion condition using a novel IL + polymer membrane material. This work was inspired by recent experimental findings from the Bara group at UA. The new class of materials was generated by adding ionic liquid molecules to …
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Impacts of reducing shipboard NOx̳ and SOx̳ emissions on vessel performance
… community has been experiencing tremendous pressures from environmental organizations to reduce the emissions footprint of their vessels. In the last decade, air emissions, including nitrogen oxides (NOx), sulfur oxides (SOx), volatile organic compounds, and particulate matter, have become …
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Application Of Composite Polymeric Membranes For Efficient Regeneration Of Physical Solvents
… most dominant CO2 capture technology used for pre-combustion capture involves the application of physical solvents. Despite the low energy required to regenerate physical solvents and their high capacity for capturing and separating acid gases from the syngas produced in a gasification plant, …
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Calcium oxide-based sorbents for CO2 capture at high temperature
… and cost-effective capture processes/materials. Pre-combustion CO2 capture from coal-fired power plants is of particular interest in integrated gasification combined cycle (IGCC) design. High concentrations of CO2 and elevated operating pressures/temperatures reduce the energy requirements of …
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Computational fluid dynamics modeling of a large bore two-stroke natural gas engine
… years in stationary applications such as gas compression and electric power generation. In the United States alone, there are over 8,000 large bore (bore >30 cm) slow speed (speed < 500 rpm) natural gas engines in use. The most common configuration is a two-stroke cycle with direct injection of …
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Impact of fuel and oxidizer composition on premixed flame stabilization in turbulent swirling flows : dynamics and scaling
… Meanwhile climate change continues to be a pressing concern that calls for the development of low CO2 energy systems. Among the most promising approaches are pre-combustion capture technologies, e.g., coal gasification and natural gas reforming that produce hydrogen-rich fuels. Another …
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NEW APPROACHES FOR MITIGATING ENVIRONMENTAL CONCERNS ASSOCIATED WITH COAL AND COAL COMBUSTION PRODUCTS
Currently, coal combustion plays an important role in meeting the energy needs of the United States. It is expected that the effective utilization of coal will be crucial for attaining energy independence for the nation in the next 25 to 30 years, if not longer. The United States burns about 20% of …