Scanning Transitiometry and Its Application in Petroleum Industry and in Polymer and Food Science

Abstract

Liquid–solid phase equilibria in asymmetric binary mixtures are not only of general interest to explore phase equilibria in three-phase (gas, liquid, solid) systems but they play a major role in understanding and monitoring the pT-behaviour of petroleum fluids. Such fluids present a vast variety of compositions in terms of their respective constituents from light gases and liquids of various molecular sizes to macromolecular solids. Nowadays, the lack of thermodynamic data on asphaltenic fluids prevents the large scale exploitation of heavy oils in deep deposits. The main concern is the uncontrolled precipitation/flocculation of heavy fractions (asphaltenes, waxes) which causes obstruction and plugging of underground as well as surface installations and pipes. Research in polymer science continues to develop actively while the concepts of thermodynamics and kinetics together with polymer chain structure enhance the domain of polymer development and transformation. In many industrial applications, during extrusion processing or as all purpose materials, polymers are usually submitted to extreme conditions of temperature and pressure. Furthermore, most of the time they are also in contact with gases and fluids, either as on-duty materials (containers, pipes) or as process intermediates (foaming, molding). Since such materials are often used in special environments or under extreme conditions of temperature and pressure, their careful characterization must be done not only at the early stage of their development but also all along their life cycle. In addition, their properties as functions of temperature and pressure must be well established for the optimal control of their processability. This also stands for phase transitions; ignorance of a phase diagram, particularly at extreme conditions of pressure, temperature, and of chemical reactivity, is a limiting factor to the development of an industrial process, e.g., sol–gel transitions, polymerization under solvent near supercritical conditions, micro- and nano-foaming processes. Natural and bio-polymers constitute an important class of components largely used in food science. Among the numerous such polymers, starch serves to illustrate the complexity of state equilibria of systems containing other species like fibers, fat, proteins, and extended ranges of water percentages. In food science, industrial processing of such systems, for example during cooking extrusion, requires in depth thermodynamic as well as thermophysical characterization of the systems to process. All above fields to cite a few, in oil industry and in polymer and food applications, necessitate the acquisition of key data.