Study of Carbon Dioxide Diffusivity Through Sand

Abstract

The purpose of this study was to measure the diffusion of carbon dioxide through sand and determine the viability of using cheap carbon dioxide sensors to measure diffusion. The data for the study was collected with the use of the K-30 and K-33 ELG carbon dioxide sensors in a diffusion cell set up made from PVC pipe fittings. The carbon dioxide concentration data was taken using software known as �Gaslab� and was interpreted using a program written by the author. The program was designed to run simulations of the column with given diffusivities, and use an optimizer to find the diffusivity that resulted in the least deviation between simulation and data; this diffusivity would then be taken as the diffusivity of the material in the column. Three series of experiments were run, the first quantified the rate of leaking within the column, the second validated the use of the column to measure diffusivity by measuring the diffusivity of carbon dioxide in air, and the third measured the diffusivity of carbon dioxide through dry sand sieved to ASTM 40-80 grain. The measured diffusivity of carbon dioxide through air matched the literature diffusivity and the diffusivity of carbon dioxide through the sand used was found to be (3.5 � 0.49) x 10-7 m2/s. These results suggest that the column set up was adequate for measuring the diffusivity of carbon dioxide through the sand sample, and could be used to measure the diffusivity of carbon dioxide or other gases through sands or porous materials.