Coal Innovation NSW: UNSW Membrane Project: Final Report

CO2 capture from post-combustion flue gases provides a pathway to mitigate greenhouse gas emissions. Given the huge volume of the flue gases to be processed and other technical constraints, gas separation membrane arises as a promising technology for such purposes among few available technologies. This can be mainly ascribed to the unique features of the gas separation membrane, including high process capacity, low energy and footprint requirement, and zero chemical discharge.  In this project, we developed three high performance prototype membranes through smart structural designs. For instance, two membrane candidates incorporated so-called TARDISlike nano-particles. As its name suggests, these nano-particles contain extremely high internal surface areas, making them “bigger on the inside”, and facilitating extremely fast CO2 transport, ideal for making CO2 capture membranes. Through a smart macro- and microstructural design, together with the carefully chosen TARDIS-like nano-materials. All the three prototypes delivered outstanding CO2 capture performance on a par with the most advanced CO2 capture membranes. A number of research centres around the globe are currently developing similar membrane types. We are, to our best knowledge, the very first one that have already moved to the next step to test these membranes under industrially-relevant conditions over a prolonged period of time. From June 2018 to March 2019, we tested the three membrane prototypes at the Vales Point Power Station using both fully and partially pretreated flue gases provided by the power station with a cumulative operating period of 16 weeks in total. From the on-site testing results, we found that, among the three membrane candidates, two of them offered sustainable long-term performance under harsh operating conditions — minimal flue gas pre-treatment.  Based on these, we concluded that these two membrane prototypes: CO2-philic composite membrane and ZIF-8 embedded nanocomposite membrane are suitable for CO2 capture from flue gases. Using the on-site results, we also performed an economic study based on the scale-up simulation results, from which, we found that apart from the membrane performance, an optimal process design is also important in terms of enhancing CO2 recovery. Similar conclusions were also obtained through an LCA study, which stated that the GHG emission footprint can be significantly reduced using a proper process configuration. From these, we recommended for future membrane study, apart from material research for higher CO2 permeation, emphasis should also be placed on process design and optimisation.