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Description:
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This dissertation intends to provide new tuning techniques for several simple cubic equations of state (EOS ) to improve their accuracy in calculating fluid phase equilibrium . It also provides graphical tools to predict some phase equilibrium phenomena from activity coefficient models . Finally , it presents simulation results for a new gas -to -liquids process .
Saturation Properties for Fluids : By deriving a new identity linking the heat of vaporization for pure components to the EOS , we are able to find new expressions for the two constants a & b in the EOS . These new expressions then allow tuning of both constants a and b to experimental saturation properties at subcritical temperatures . These new tuning procedures prove effective to the point where the simpler Redlich -Kwong EOS provides better results with our procedure than does the usually superior Peng -Robinson EOS with conventional procedures .
Activity Coefficient Models : This dissertation shows the flexibility of four activity coefficient models in the prediction of three fluid phase equilibrium phenomena . From these models we successfully developed new graphs that allow one to identify the presence of any of the three phenomena by visual inspection without performing a complex calculation as seen in current texts .
Remote Natural Gas : This dissertation presents simulation results of a new gas -to -liquids process which converts natural gas to liquid transportation fuels .
Based on the assumption of adiabatic reactions , our simulation results show that methane conversion increases with higher reaction temperature and longer residence times . Hydrogen can both inhibit methane decomposition and reduce coke formation . The rich components in the natural gas are found to decompose very fast and they have a vast quenching effect on the whole reactions . Recycling of unreacted methane also increases overall methane conversion . Finally , our simulator provides very close prediction of the experimental results from a pilot plant . Thus , we conclude that the simulation work is basically successful in fulfilling the goal of this research . |