Within the challenge of mitigating climate change, CO2 capture and storage (CCS) is considered as promising option to reduce the atmospheric CO2 emissions. In power plants three different concepts have emerged: post-combustion applying an end of pipe technology to remove CO2, oxy-fuel combustion and pre-combustion (i.e. H2 routes). The main technologies applicable for CO2 separation are chemical absorption with amines, physical absorption and adsorption and membrane processes.The competitiveness of these technologies depends on the characteristics of the gas to be treated, the operating conditions and the purification purpose which influence the separation efficiency, the energy (heat and power) demand and the equipment costs. The purpose of this project is to study in detail physical absorption processes (i.e. Selexol, Rectisol) based on literature data and by applying computer aided methods. The aim is to assess the processes performance (i.e. separation, energy demands, costs) for different operating conditions and to set up thermo-economic models to define the performance. Finally, these models are included in pre-combustion processes in order to study the process integration and assess the process performance with regard efficiency, costs and environmental impacts.