Preliminary Scoping and Thermodynamic Modelling of CO2 Compressors for Carbon Capture and Storage

Abstract: Power production represents one fourth to one third of all CO2 emissions. Carbon Capture and Storage (CCS) in one way to approach the increasing problem with CO2 emissions from fossil fuelled power plants. The CO2 is separated, compressed and transported to a final storing site. To allow more efficient transport and to match the pressure of the final storing site, the CO2 is compressed to a supercritical fluid. The additional equipment that a CCS system requires will have a negative effect on the overall power plant efficiency and it is of great importance to minimise this consequence. This thesis is a preliminary scoping of different CO2 compression technologies and ways to improve them prior to transportation to a final storage site. The report compares existing, adapted and novel compression technologies in terms of power consumption. CO2 is currently being compressed in for example urea production using integrally bull geared compressors. In-line barrel compressors used in the gas industry show promising possibilities to be adapted for CO2. Two novel ways that has been investigated are a high pressure ratio compressor that uses oblique shock waves to compress the gas and a cryogenic system where the CO2 first is compressed, then cooled in chillers and then pumped to the required delivery pressure. The different compression technologies were modelled in IPSEpro, a thermodynamic simulation tool and the data was validated against TechUtils, a thermodynamic calculation tool. The result shows that compared to the current compression technologies for CO2, novel or adapted methods can reduce the power consumption with approximately 7 %.