Computational modeling and experimental investigation of aqueous potassium carbonate droplets in superheated steam flow

The paper describes a computational study and an experimental investigation of aqueous potassium carbonate droplets in superheated steam flow for potential applications in mitigation of superheated geothermal steam. The computational model included the boiling point elevation due to the droplet salt concentration as well as other concentration-dependent physical properties of the salt solution. Various phenomena involved in the process, such as breakup, transport, heat transfer, boiling and coupling between droplet and steam phase were taken into account. To validate the simulation results from the model, a laboratory scale experimental setup was built and experiments were carried out for different salt solution injection concentrations upto 5.27 mol kg(-1) in superheated steam at 421 K. Results from the simulation were in accordance with experimental measurements, showing an increase in boiling point elevation with an increase in injection salt solution concentration. The temperature values obtained from the simulation are slightly higher than those measured with an average deviation of 1.5 K, which can be explained by a small degree of heat loss from the apparatus not accounted for in the model. Results from the simulation for concentration were also in accordance with the experimental measurement, showing an increase in concentration of the salt solution droplets, collected at the separator bottom. The concentration values obtained from the simulation are lower than that from the measurement with an average deviation of 20%.