International audienceCO 2 transportation is an integral part of the CCS chain. After capture, CO 2 needs to be transported to locations whereby it is stored or alternatively used in various processes. CO 2 can be transported via ship or pipeline. In both cases, the required compression pressure can be 100–300 bar, depending on the distance and intended disposal or use of CO 2. The CO 2 rich stream can contain a lot of impurities which can modify the phase diagram and change the thermophysical properties of the stream in comparison with the ones of pure CO 2. Indeed, along with carbon dioxide, a great number of compounds such as water, O 2 , N 2 , Ar, SOx, NOx, H2 and CO can be present at different levels of concentration. During transportation by pipeline, if the pipe suffers a major fracture due to an accidental release or a failure, CO 2 can rapidly expand and cool: vapour cloud followed by solid formation of CO 2 may appear. The impurities could change the characteristics of the leak and change the conditions and compositions of CO 2 clouds and solid. The presence of water can also be a source of gas hydrate formation, ice or corrosion. In this communication we will present new experimental data and their modelling concerning the phase diagrams of systems rich in CO 2 and their thermophysical properties. Comparisons of the results obtained using different equations of state are also reported