Design of a high pressure flow reactor for gas phase kinetics
A High Pressure Flow Reactor (HPFR) was obtained, redesigned, and validated in order to understand and fully characterize chemical kinetics with respect to gas phase chemistry, specifically to increase the operating parameters in order to study fuels in engine like conditions (high temperatures, pressures, and fast residence times). This desire to study fuels at such extreme conditions stems from the need for well validated Reaction Mechanisms for use in engine modeling to improve on fuel efficiency and energy output. Original operating parameters for the Flow Reactor included temperatures up to 1,000K, pressures up to 12atm, and an obtainable residence time of 0.1s; the final designed and validated HPFR increased the operating parameters to a maximum temperature of 1,473K, a maximum pressure of 30atm, and a theoretically obtainable residence time of 1.7ms using a Water-Cooled Sampling Probe sampling method and 84ms using a sampling Syringe method. Inert Nitrogen Preheater controls were improved upon to allow for greater heating accuracy as well as accommodating a larger flow rate for a reduced Reactor residence time. Reactor Heaters were included to ensure a uniform Reactor temperature, allowing Reactor temperatures up to 1,473K, and significantly reducing experimental run time. A fuel vaporization system was designed to guarantee a fully homogenous mixture of vaporized fuel and carrier gas, specifically for real fuels consisting of multiple fuel components with varying volatilities. A LabVIEW system was implemented in order to improve upon the usability and ease of use for controlling the HPFR. Two sampling methods to feed to the Gas Chromatography Flame Ionization Detector (FID) and Thermal Conductivity Detector (TCD) were designed: a water-cooled sampling probe for faster residence times with greater control of experimental data, and a sampling syringe for ease of implementation for various testing setups. Various other improvements were implemented to reduce startup times, increase validity of experimental data, and improve the usability of the HPFR. Validation was completed both numerically and experimentally for specific sections of the HPFR. Temperature and pressures were experimentally determined in order to verify agreement with planned design parameters. A fully homogenous gaseous mixture and Plug Flow was ensured inside the Reactor by utilizing Ansys FLUENT Computational Fluid Dynamics software as well as experimentally by determining the radial temperature profile in the fully developed region of the Reactor. Lastly, Ethane thermal decomposition modeling using CHEMKIN with a well-known Ethane Reaction Mechanism was completed to determine operating conditions for future experimental Ethane studies.
high pressure, gas phase kinetics, flow reactor, design
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Colorado School of Mines. Arthur Lakes Library