Molecular and petroleum thermodynamics

Prof John M. Shaw, University of Alberta

Dr Kenneth Kroenlein, NIST

Thursday 20th September 2018
Time: 4pm
Venue: Ramsay LT, Christopher Ingold Building, followed by drinks and nibbles in the Nyholm Room
Contact: Karen Stoneham
Tel: 0207 679 7306

An Experimentalist’s Perspective on the Phase Behaviour and Transport Properties of Nano Colloids - John M. Shaw

The phase behavior and properties of nanocolloids is driven by the interplay between inherently attractive dispersion energies leading to particle flocculation and potentially to phase separation, and repulsive energies that stabilize particles in a dispersed form. For dispersion energies large relative to thermal energy all individual particles become flocculated over time. The state/structure of flocs is time and flocculation mechanism(s) dependent but largely temperature independent. Macroscopic phase(s) may emerge over time. For dispersion energies comparable to thermal energy, equilibrium between flocculated and individual particles occurs and distinct macroscopic phases where species have equal chemical potentials may form. For dispersion energies weak compared to thermal energy, particle flocs do not form. The colloid comprises a single stable phase. Repulsive energies can arise from electrostatic forces among particles, sorption of species from solution onto particles and they help stabilize dispersed particles. In this contribution, we review key concepts, then focus on the phase behaviour and properties of sols (nanoscale domains are dispersed in a liquid) and gels (nanoscale domains form a three-dimensional network in a liquid) where equilibrium concepts apply. The nanoscale domains comprise well-defined and discrete particles (silica, diamond, carbon nanotubes, gold) with and without ligands on their surfaces, and poorly defined asphaltene-rich domains in mineral oils. Phase diagrams and rheology of sols + nonsorbing polymer, transitions from Fickian to Single-File diffusion as sols become more concentrated, and interfacial tension results are presented. Parallels among these cases provide surprises and insights worth pursuing, and illustrate challenges for modelling equilibrium, interfacial and transport properties both for well-defined and poorly defined nano colloids. Applications from mining to medicine, and from petroleum to pesticides are implicated!

Overcoming Scarcity in the Scientific Literature - Kenneth Kroenlein

Modern scientific progress is being driven by larger data sets and more comprehensive analyses.  In the Thermodynamics Research Center at the National Institute of Standards and Technology (NIST) in the US, we specialize in the curation of high quality thermophysical and thermochemical property data for well-defined chemical systems and their validation using domain expertise and information technology.  Given the many fundamental interrelationships between thermodynamic properties, a strong foundation in physical modeling, and the heuristics that industrial practice has developed, this generates the need to synthesize a range of heterogenous information channels into coherent recommendations.  This is made all the more challenging in that for any particular chemical system, the particular models and data availability will vary wildly.  Every data scenario becomes unique.

In this presentation, we will discuss a range of tools that TRC is developing for this challenge.  Particular areas to be discussed include: the general development of algorithms for empowering domain experts to quickly and comprehensively evaluate new data in a historical context, a quantum chemical toolchain for large-scale prediction of ideal gas enthalpies of formation with uncertainties on par with experimental calorimetry, and application of machine learning techniques to the very limited data sets available in the chemical literature.  In all this, it is important to consider that while the entirety of relevant data reported in the open literature is small on the scale of Big Data, high-quality data points are costly in both time and money, and thus researchers must take maximal advantage of every piece of information available.

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