D11.4 Membrane-assisted CO2-liquefaction scale up to TRL7–8

The membrane-assisted CO2-liquefaction carbon capture process has been investigated by process simulations and laboratory experiments to validate its performance. To increase the TRL level to 7-8, a pilot facility with real flue gas from a cement plant in an operational environment is required.
The membrane-assisted CO2-liquefaction process is a hybrid between two carbon capture technologies, each of which are unfit for post-combustion carbon capture by itself. By combining the two technologies, they can both operate in their respective favourable regime of operation. The process consists of a single membrane stage for bulk separation of the flue gas from a CO2 concentration in the range 17–20 mol%, delivering crude CO2 with a purity up to 60–70 mol%. This bulk separation is followed by CO2 liquefaction and two stages of phase-separation for purification up to above 99 mol% purity. The final liquid CO2 stream can be pumped to the transport pressure and reheated in the case of pipeline transport, or directly extracted as liquid CO2 for ship transport.
In this work, a preliminary design of a combined membrane and CO2-liquefaction test plant has been proposed. The baseline mass balance flowsheet has been simulated in Aspen HYSYS, and the design is further supported by recent experience from a laboratory pilot plant with a capacity of around 10 tons CO2 per day. The simulated plant is designed for 60 % CCR and capacity to capture 100 tons CO2 per day. A membrane area of 10 000 m2 is required according to our model results. The plant delivers liquid CO2 with at least 99.4 % purity, but higher purity may be attainable through further reduction of pressure in the low-pressure CO2 purification separator.
The necessary main components, equipment types and availability of off-the-shelf equipment have been investigated. Suggestions on how to control the process, based on experience from the laboratory experiments, are also provided.