Parameter Estimation in Complex Algebraic Models: Solubility of Co2 in Brine

Abstract

A new form to calculate the activity coefficient of CO2 in aqueous solutions of chloride salts is presented. The model is coupled with an external solubility model to verify its performance against experimental data in temperature range of 50ºC-120ºC and pressures up to 200 bar, showing the model gives more accurate results than some well-known solubility models. Moreover, it presents a procedure to estimate parameters in complex algebraic models via MATLAB ® , testing seven built-in optimization algorithms and mapping both individual and joint confidence interval.