Aspen HYSYS process simulation and Aspen ICARUS cost estimation of CO2 removal plant
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- Master i teknologi 
An Aspen HYSYS model of CO2 removal was developed and modified with a split-stream configuration in order to reduce energy consumption in the reboiler. The model has been calculated with variation of parameters to optimize the process and find an optimum solution. For the selected base cases the heat exchanger minimum temperature difference was specified to 10K and the removal efficiency was 85%. The reboiler duty of 3.8 MJ/kg CO2 removed for the standard process without split-stream was achieved with 18 absorber stages. 3.4 MJ/kg was achieved for the process with split-stream and 24 absorber stages. It was possible to further reduce reboiler energy consumption for the case with split- stream down to 3.0 MJ/kg with 26 stages in the absorber. In this case a heat exchanger minimum temperature difference was 5K. Equipment cost estimations were calculated in Aspen ICARUS. The total installed equipment cost of the selected standard CO2 removal process without split-stream was 760 MNOK. With a steam cost of 0.1 NOK/(kWh) the energy net present value for this process for a period of 10 years was 975 MNOK. The investment cost was increased with 212 MNOK due to added complexity of the process with split- stream and the operation cost for a period of 10 years was reduced with 139 MNOK. It means that the split-flow configuration is not economically attractive for 10 years period. The split-stream alternative becomes more attractive when the calculation period increases. With a period above 20 years the split- flow becomes most economical. The split-stream alternative also becomes more attractive when the energy cost increases. The combination of Aspen HYSYS and Aspen ICARUS is a good tool for evaluating different process configurations. There are still challenges in improvement of the simulation robustness and the cost estimation accuracy.