Simulation study on Benfield’s hot potassium carbonate electrolyte system: Effects of temperature, pressure, and concentration on solubility index

Benfield’s Electrolyte system known as potassium carbonate aqueous solution has been analyzed to investigate the solubility index in varying temperatures, pressures, and concentrations. Redlich-Kwong thermodynamic model has been used to calculate the vapor-liquid equilibrium between water and carbon dioxide. In contrast, the electrolyte non-random two-liquid (ELECNRTL) model is used to model the activity coefficient, transport properties, and solubility index. The model extended for the system of carbonate/bicarbonate mixture at a temperature range of 280- 403 K, pressure of 1 and 2 bar, and carbonate/bicarbonate concentrations ranging between 2.1706/0.0 and 0.0/2.9954 mole/kg H2O. A case study was performed on the crystallization of electrolytes K2CO3 and KHCO3 in the Benfield process to demonstrate the model applications. The results suggest the possibility of operations error that may have initiated salt crystallization through excessive heating or draining of the HPC solution. The outcome results showed a large deviation from the normal tendency for the transport properties and solubility index at an approximate temperature of 377 K. The simulation results showed a sufficient accuracy for the 30 wt% HPC solution with errors between the simulation results and the published data within 1 to 5%.