I thank Professor Mark A. M c Hugh for his guidance throughout my undergraduate and graduate education. Dr. M c Hugh's guidance has truly been a significant factor in my growing love for the field of chemical engineering. Lastly, I would like to note that Dr. M c Hugh has never failed to keep me entertained and inspired through his lectures. It has been a pleasure working with Dr. M c Hugh. I would also like to thank Dr. Reddy Mallepally for working closely with me and teaching me how to perform high-pressure experiments. I appreciate Dr. Mallepally's guidance as it has been an integral part of my development as a researcher. In addition, I thank Dr. Babatunde Bamgbade for always lending a helping hand and offering me additional advice from his previous experiences.

The development of reference correlations for viscous fluids is predicated on the availability of accurate viscosity data, especially at high pressure, high temperature (HPHT) conditions. The rolling ball viscometer (RBV) is a facile technique for obtaining such HPHT viscosity data. A new, universal RBV calibration methodology is described and applied over a broad T-p region and for a wide range of viscosities. The new calibration equation is used to obtain viscosities for n-hexadecane (HXD),

Bubble point pressures of six binary mixtures at two compositions each have been measured utilizing a static method. The performance of the apparatus was characterized from bubble point measurements of R32 + R125 for which 19 literature studies are available for comparison. The mixtures studied were as follows: R1234yf + R134a, R134a + R1234ze­(E), R1234yf + R1234ze­(E), R125 + R1234yf, R1234ze­(E) + R227ea, and R1234yf + R152a. For each mixture, measurements were conducted from 270 to 360 K or to within approximately 10 K of the critical temperature of the pure component with the lower critical temperature. A total of 196 bubble point pressures are reported with combined expanded uncertainties (k = 2) ranging from 0.1 to 0.6%. The measured data are graphically compared to available literature data.

Vapor-liquid equilibria and mixture densities for 2,2,4,4,6,8,8-heptamethylnonane + N 2 and n-hexadecane + N 2 binary mixtures to 535 K and 135 MPa Supplemental Information

Highly branched alkanes exhibit enhanced free volume relative to their straight chain analogs leading to increased solubility of sparingly soluble gases, such as N 2 , as well as lower hydrocarbon-gas interfacial tension (IFT) values. In this study high-pressure, high-temperature (HPHT) IFT data are reported for two C16 isomers, hexadecane (HXD) and heptamethylnonane (HMN), with N 2 from ~298 to 573 K and pressures to 100 MPa. The IFT data are modeled with Density Gradient Theory (DGT) in conjunction with the Perturbed-Chain, Statistical Associating Fluid Theory equation of state (EoS) with pure component parameters calculated with three different group contribution (GC) methods. One GC method (B-GC) is developed from a database of high-pressure density data and the other two GC methods (S-GC and T-GC) are developed from a large database of pure component vapor pressure and saturated liquid density data. DGT calculations incorporating the B-GC method reasonably represent the IFT for both HXD + N 2 and HMN + N 2 at low temperatures, but result in significant deviations from experimental IFT values

In this work, a Rolling-Ball Viscometer/Densimeter is used to measure high-pressure, hightemperature (HPHT) density and viscosity data from 298.2 to 532.6 K and pressures up to 300.0 MPa for three different diesel fuels. The densities and viscosities have combined expanded uncertainties of 0.6% and 2.5%, respectively, with a coverage factor, k = 2. Two of the diesels, Highly Paraffinic (HPF) and Highly Aromatic (HAR), contain a larger paraffinic and aromatic content relative to the others, and are standard engine test fuels. The third is a Ultra-Low Sulfur Diesel (ULSD) that resembles an unfinished commercial diesel. Detailed compositional information is also reported for each diesel that provides a basis for interpreting the impact of composition on density and viscosity at high pressures. Both density and viscosity data are correlated to Tait-type equations with uncertainties of 0.6% and 4.0%, respectively. The Tait equations provide a facile means to compare observed differences in the density-pressure and viscosity-pressure profiles of the three different diesels. Density data are modeled with the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) equation of state (EoS) with pure component parameters calculated representing diesel as a single, pseudo-component only requiring average molecular weight (Mave) and hydrogen to carbon ratio (RH/C) as inputs. Viscosity data are modeled reasonably well using entropy scaling coupled with the PC-SAFT EoS and information on the diesel Mave and RH/C. The HPHT viscosity data are also modeled reasonably well with Free Volume Theory (FVT) with model parameters correlated to Mave and RH/C.

No abstract

Speed of sound data measured using a dual-path pulse-echo instrument are reported for binary mixtures of 1,1,1,2-tetrafluoroethane (R-134a), 2,3,3,3-tetrafluoropropene (R-1234yf), and trans-1,3,3,3-tetrafluoropropene (R-1234ze­(E)). For each binary mixture, the speed of sound is studied at two compositions of approximately (0.33/0.67) and (0.67/0.33) mole fraction. The conditions covered in this study range in temperature from 230 to 345 K and from pressures slightly above the bubble curve up to a maximum pressure of 51 MPa. However, to avoid potential polymerization reactions, data for mixtures containing R-1234yf are limited to a maximum pressure of 12 MPa at temperatures below 295 K and 8 MPa at temperatures above 295 K. The mean uncertainty of the measured speed of sound is less than 0.1%, where relative combined expanded uncertainties at individual state points range from 0.04 to 0.4% of the measured speed of sound value. The greatest combined expanded uncertainties are encountered as the state point approaches the mixture critical region where weakened echo signals and lower speed of sound values are observed. The reported data are compared to available REFPROP mixture models, which are not adjusted using the data reported here, with average absolute deviations ranging from 0.27 to 0.75% with maximum deviations as high as 1.1%. The comparisons to the REFPROP correlations show that further adjustments to the mixture models are needed to provide a representation of the data within its experimental uncertainty.