Doctor of Philosophy (PhD), Ohio University, 2020, Chemical Engineering (Engineering and Technology)

The treatment of produced water (hereafter referred to as brine) from oil/gas reservoirs will prove a significant cost burden for producers; the U.S. produced 21 billion barrels of this waste in 2019 alone. Reinjection is the traditional management method; however, the availability of injection disposal is dependent on the location of the well, and is potentially unavailable when the well is remote. Average disposal costs can reach up to $8.00·bbl-1, with costs increasing with brine salinity. A portion of this study discusses a novel technique employed to treat high salinity brines, called supercritical water desalination (SCWD). This technique utilized favorable characteristics of water near the pseudocritical point to separate dissolved solids. Two scenarios were considered in a techno-economic analysis; one which removed all dissolved solids from the brine (termed “zero liquid discharge” (ZLD), the other concentrated brine to reduce liquid waste volume. For high salinities, this technique was shown to be economically feasible with costs ranging from $3.49 to $17.28·bbl-1 in an expanded sensitivity analysis. Additionally, this study considered the thermodynamic characteristics of a binary system of CaCl2-H2O to assist in brine modeling efforts for future studies. A series of correlations were presented to describe the critical line, vapor-liquid equilibria, specific volume and enthalpy for CaCl¬2-H2O. The correlations were augmented by additional specific heat data obtained at pseudocritical condition, allowing for further tuning of the specific enthalpy correlation.

Committee: Jason Trembly (Advisor); Natalie Kruse-Daniels (Committee Member); Sumit Sharma (Committee Member); Guy Riefler (Committee Member); Marc Singer (Committee Member) Subjects: Chemical Engineering

Master of Science (MS), Ohio University, 2015, Physics and Astronomy (Arts and Sciences)

The primary objective of this thesis is to develop the theoretical tools for a rapid calculation of nuclear level densities for neutron-rich nuclei not found in the laboratory, but commonly encountered in astrophysical settings. Toward this goal, the thermal properties of 4820Ca , 13250Sn, 20882Pb and 5727Co were calculated using statistical methods. The single-particle levels for these nuclei were obtained from thermal Hartree-Fock and Hartree-Fock-Bogoliubov calculations for two model Hamiltonians based on the Skyrme forces SkO' and SkM*. The calculated nuclear level densities are in better agreement with experimental data for 5727Co and 20882Pb for the SkO' model. Both models fail at very low excitation energies owing to the approximations made in the statistical treatment. A new finding of this work is the discontinuity in the specific heat at constant volume for 5727Co in the excitation energy range of 1.5-3 MeV, which indicates a phase transition from the superfluid state to normal matter. To our knowledge, this feature has not been reported in the literature for this nucleus. We also found the physical reason why calculations for open shell nuclei sometimes yield a diverging pattern in the single-particle level densities at low excitation energies. This behavior is caused by a combination of two effects: high degeneracies and close proximity of partially filled levels to the chemical potentials of neutrons and protons. A practical strategy is proposed for future work in which results of more microscopic, but computer-intensive, calculations that avoid the divergences found in statistical treatments at very low excitation energies are stitched with the results at moderate to high excitation energies from the latter approach.

Committee: Madappa Prakash Prof. (Advisor); Douglas Clowe Prof. (Committee Member); Gang Chen Prof. (Committee Member) Subjects: Physics