Research in phase equilibria for solutions containing salts or
sour gases. Development and application of thermodynamic models for
solutions that contain salts (Extended UNIQUAC).
Research in phase equilibria for solutions that contain ions is
essential in relation to the absorption of carbon dioxide from the
flue gas from power plants. By absorption of carbon dioxide
carbonate, hydrogen carbonate, carbamate, and additional ions are
formed depending on the solvent. The simulation of this absorption
requires a thermodynamic model for salt solutions (electrolyte
solutions). Phase equilibria in solutions consisting of carbon
dioxide, ammonia, and water can be accurately described by the
Extended UNIQUAC electrolyte model.
This research can also be used for predicting the water activity
in multi component solutions of food preservatives. The
thermodynamic model is able to predict the water activity in a
mixture based on parameters determined from binary systems. This
can be used for improving the quality of food and minimizing the
amount of preservatives in food as the water activity is
determining for the growth potential of micro organisms.
In the oil industry and during the production of geothermal
energy, salts may precipitate and form scale inside tubes and
valves. This happens when solutions of salts that have an increased
solubility at high temperature and pressure are cooled and
depressurized. Relevant salts are gypsum, barium sulfate, strontium
sulfate, calcium carbonate, magnesium carbonate, and more. By using
the Extended UNIQUAC model, the risc of precipitation can be
calculated.
Salt influences the vapor-liquid equilibrium of alcohols and
other organic solvents in water. In some cases, a liquid-liquid
split takes place by adding salts to mixtures of water and organic
solvents. In some cases this phenomenon can be used for separating
water from organic solvents instead of performing a
distillation.
By combustion of biomass to produce electricity and district
heating, a fly ash consisting of soluble salts is produced. Some of
the soluble salts could be used as fertilizer if they were not
mixed with heavy metal salts. Because of the content of heavy
metals, the fly ash can not be deposited in landfills. The heavy
metal salts therefore have to be separated from the remaining part
of the fly ash. By modeling the system consisting of an aqueous
solution of the components of the fly ash, a process for separating
the fly ash into its pure components can be developed.