EXPERIMENTAL INVESTIGATION OF ABSORPTION OF CO2 IN WATERBASED SOLUTIONS.

Abstract

An investigation of Carbon dioxide absorption and desorption is carried out to understand the diffusion and flow mechanism of a pressurized CO2 gas cap in an water-based solution (WBS) and to accurately quantify the \cooo absorbed by the system. This is particularly of interest to further understand the behaviour of CO2 when injecting it into an aquifer reservoir for permanent storage, however it proves to be useful knowledge for several applications for the carbon capture and storage process cycle. A series of pressure decay experiments were carried out in a non-invasive PVT cell able to withstand pressures up to 7 bar. The cell is cast in an epoxy block to avoid visual phenomenon’s, and is transparent to allow for the flow mechanisms to be apparent. To further highlight the flow mechanisms pH indicator was added to the alkaline solution. The experimental data was accompanied by a video recording for each experiment to understand the relation between the mass transfer patterns, pressure and saturation of the system.

The experimental data pressures were analysed using a simple pressure boundary model, for the diffusion coefficient and final saturation pressures to be calculated. Once saturation pressure was reached the WBS was flashed to atmospheric pressure to accurately quantify the CO2 absorbed. This allowed for a mass balance of the CO2 to be carried out to accurately quantify the moles absorbed by the WBS at the different pressures.