Otway capture research
CO2 is a major contaminant in natural gas and its concentration varies with location. Many known reserves of natural gas are undeveloped due to the high CO2 content of these fields and the high cost associated with separating large quantities of CO2 from the gas using conventional gas sweetening technologies. Conventional methods for removing CO2 from natural gas based on chemical solvents are not ideally suited to such conditions because of the large amount of energy consumed in these processes. In addition to this, the large footprint of these conventional solvent systems makes it a challenge to deploy them in offshore and subsea environments. Developing new technologies at scale in the laboratory alone is prohibitively expensive due to the high pressure conditions, the volumes of gas involved and reproducing typical feed conditions. The capture pilot plant at the Otway International Test Centre was established to test and demonstrate CO2 capture from natural gas using membrane and adsorption technologies to deliver compact, robust, low energy and low cost CO2 separation technologies for high pressure and high CO2 content applications.
The capture skid was designed to operate at pressures of up to 90 bar and CO2 compositions between 15 to 70 vol% in the feed gas to mimic various gas field compositions. The plant operated with a two-bed pressure swing adsorption (PSA) unit (with intermittent feed intake to mimic a system with continuous feed) and three membrane units with the ability to inject trace components such as H2S to investigate the effects of impurities on the performance of the materials tested. The new materials tested included:
- Novel zeolite adsorbent with enhanced kinetics by ion-exchange.
- Flat sheet and spiral wound and CAP (Continuous Assembly of Polymers) membranes (Ultrathin composite membranes).
- ZIF/Pebax based hollow fibre composite membranes.
Tao, L., et al., CO2 capture from high concentration CO2 natural gas by pressure swing adsorption at the CO2CRC Otway site, Australia. International Journal of Greenhouse Gas Control, 2019. 83: p.1-10
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