Exploring adsorption technologies for cattle enteric CH4 capture: from data collection to process simulation

Ruminants, mainly dairy cattle account for about one third of the global anthropogenic methane emissions. Considering that a cow emits about 500 L/d of methane [1] and in view of the increasing population of cows due to the intensive farming activities, the daily methane emission is considerable and is likely to further increase. Our project focuses on exploring adsorption technologies to mitigate the environmental impact of zootechnical facilities. Preliminary samples collected using characterized activated carbons have been analyzed through TPD analysis. We identified two major challenges: capturing methane at low partial pressures and competitive adsorption due to higher CO2 concentration in cattle barns, which favors CO2 uptake over methane. The design work, performed using Aspen Adsorption® V11, revealed the necessity of a two-stage adsorption system, as shown in Fig. 1. An initial “guard bed” is used to adsorb carbon dioxide and other gases from the barn, while efficiently adsorbing methane in the second bed. The plant has been optimized for continuous GHGs removal and sized appropriate for construction near cattle barns. The choice of an adsorption-based system was influenced by its cost-effectiveness, scalability and the abundant supply of adsorbent materials.