(619c) Removal of H2S and CO2 from Raw Natural Gas Using Wood Fly Ash from Alberta Kraft Pulp Mills

Jing Jing Cai¹, Paolo Mossone¹

¹Office Research of Innovation, Northern Alberta Institute Technology of Alberta, AB, Canada

Keywords: Adsorption, wood fly ash, Natural gas processing, forestry residue

Acid gas components such as H₂S, CO₂ and other impurities must be removed from raw natural gas in order to meet pipeline specifications. Comparing to traditional amine absorption process being widely applied in oil and gas industries, the use of solid adsorbents represents an attractive option to reduce operational complexity. Several materials such as synthetic zeolites, engineered metal oxides and activated carbons have been developed and tested, but the costs associated with the manufacturing, transportation and operation poses serious cost barrier to their deployment.

In this work, we prepared low cost adsorbents using wood fly ash from Alberta Kraft pulp mills to simultaneously remove H₂S and CO₂ from raw natural gas. Wood fly ash is a by-product of Kraft pulping that is currently landfilled and that is potentially available on a regional scale to natural gas producers in Alberta. Comprehensive characterization of wood fly ash was carried out to determine functional groups present on the surface of the fly ash towards adsorption of H₂S and CO₂ respectively. The ash was then pelletized and packed in a multi-stage continuous flow adsorption column to test its adsorption capacity for simultaneous removal of CO₂ and H₂S from natural gas. Based on these results we unveil a range of fly ash adsorbents capable for either selective H₂S or CO₂ adsorption or for simultaneous H₂S/CO₂ adsorption from natural gases. This research aims to provide a viable alternative to existing sweetening technologies that can reduce the environmental impacts.