Aqueous electrolytes and non-electrolytes in under sub-critical and super-critical conditions

点击翻译按钮获取中文摘要

Many geological and industrial processes take place at conditions far beyond the range of conventional room temperature measurements. The objective of this proposal is to develop the knowledge base and theoretical understanding needed to describe the behaviour of aqueous systems at extremes of temperature and pressure encountered in electrical power stations, advanced nuclear reactors, geothermal ore bodies, deep-ocean hydrothermal vents, and the thermal recovery of heavy oil. Sensitive flow calorimeters and densimeters, constructed of inert materials to withstand the corrosive conditions, will be used to determine the thermodynamic properties of simple electrolytes and organic molecules in liquid water at temperatures up to 400 oC and pressures as high as 350 atmospheres, to examine the effects of ionic charge and organic functional groups under conditions approaching the critical point of water. The form of the chemical species, and their equilibrium constants, will be determined by in situ measurements in high temperature, high pressure flow cells using UV-visible spectroscopy, Raman spectroscopy, calorimetry, densimetry and a one-of-a-kind, high-precision conductance apparatus, all capable of reaching sub-critical or supercritical conditions. Diamond anvil and high pressure flow cells will be used in conjunction with confocal Raman microscopy to examine phase relations and to identify major chemical species by direct observation at extremes of temperature and pressure. These measurements will yield new thermodynamic data, transport properties, semi-empirical models, and theoretical methods for predicting the properties and phase behaviour of aqueous inorganic and organic solutes in water-based industrial and natural systems operating under extremes of temperature and pressure The novelty in the work lies in the very extreme conditions being studied, the potential for identifying unusual effects, and the need to develop specialized instrumental techniques to obtain quantitative data for complex aqueous systems under these very aggressive conditions.