Improved Apparatus for Dynamic Column-Breakthrough Measurements Relevant to Direct Air Capture of CO<sub>2</sub>
W. Sean McGivern, Huong Giang T. Nguyen, Jeffrey A. Manion
Abstract
Dynamic column-breakthrough (DCB) measurements are valuable for characterizing the adsorption of gaseous species by solid sorbents and are typically used for high concentrations of adsorptives, often at elevated temperatures and pressures. However, adsorbents for the direct capture of carbon dioxide (CO 2 ) from natural air demand measurement capability at low partial pressures of CO 2 at atmospherically relevant temperatures and pressures. We have developed a new apparatus focused on the measurement of DCB curves under typical tropospheric conditions. The new apparatus is described in detail and validated with breakthrough curve measurements. Samples of 13X zeolite on the order of a few hundred milligrams have been tested using a low CO 2 concentration gas mixture, and adsorption capacities are reported at 233.1–323.1 K and total pressures of 351–1078 hPa. Measurement uncertainties related to timing, flow, temperature, and concentrations are analyzed, and the present results at 273, 298, and 323 K are compared with static measurements obtained with a manometric adsorption analyzer. In addition, experiments at a typical atmospheric CO 2 concentration of 400 μL·L –1 have been performed.