Depressurization of CO2-N2 and CO2-He in a pipe: Experiments and modelling of pressure and temperature dynamics

•An experimental setup for decompression of CO2-rich mixtures in a tube is presented.•Pressure and temperature are measured with a dense spatial and temporal resolution.•Experiments with N2 and He as impurities are reported.•Comparison with a homogeneous equilibrium model including solid CO2 is performed.•Both pressure and temperature dynamics are significantly affected by the impurities.