O ne of the measures for reducing global CO 2 emissions is to capture CO 2 and store it safely in geological formations. Safe and effective CO 2 management requires reliable tools for calculate accurately the properties of both pure CO 2 and CO 2 in mixtures. If the default models and parameters of commercial flow sheeting tools are used when predicting the solubility of water in CO 2 and CO 2 in mixtures may not always result in satisfactory results. Having in mind the need for reliable operation of the processes along the CO 2 capture, transport and injection chain, reliable tools are cardinal.
The purpose of the present work has been to establish reliable model parameters by selecting equation of state (EOS) models for evaluation, develop a database of reliable experimental data on solubility of H 2 O, CO 2 and CH 4 based on data collected from literature, use the data to establish and suggest model parameters based on the database, and test and document the ability of the various EOS models to predict the solubility of H 2 O in CO 2 or a mixture of CO 2 and CH 4 .
Experimental data on solubility of H 2 O, CO 2 and CH 4 were collected from literature and compared with a model based on the rest of the experimental data in order to evaluate the quality of the data. The second order SRK-HV (SRK-Huron Vidal) model with six parameters was used as model for evaluating the experimental data.
The models SRK-VdW (Soave Redlich Kwong, Van der Waals mixing rules), SRK-HV (SRK-Huron Vidal) and the CPA (Cubic Plus Association) was evaluated. Based on the data for the mutual solubilities of H 2 O, CO 2 and CH 4 , new model parameters were adapted for the SRK-HV, and the CPA models. Solubility of H 2 O in CO 2 and H 2 O in the CO 2 -CH 4 mixture was emphasized.
The second order SRK-HV model produced acceptable results with deviation from 3% to 9% between experiments and the model. The CPA model was less accurate, producing results with deviation from 9% to 35% between experiments and the model. The SRK-VdW model gave two different binary coefficients, one for solubility of water in liquid CO 2 and another for solubility of CO 2 in water. That gave same deviation as the SRK-HV model, (typically 7% for H 2 O in CO 2 but 93% for CO 2 in water, or 4% for CO 2 in water but 390% for H 2 O in CO 2 with another binary coefficient). The SRK-VdW is not indented for use of two different binary coefficients.