Determination of effective diffusivities and convective coefficients of CO2 in gypsum plasters by dynamic single pellet experiments

The effective diffusivity values decreased with increasing the pressure drop. In the range of pressure drop studied, both diffusive (at low pressure drops) and viscous (at high pressure drops) flows for CO2 diffusion in construction gypsum and perlite plasters were dominant. But, the diffusion flow type which is important for machine plaster was only the viscous flow at all pressure drops. Finally, the Darcy coefficients of the gypsum plaster pellets were calculated. It was observed that the results were in agreement with the literature results obtained for porous solids similar to porous gypsum plaster pellets used in this study.