This concentration can be reduced substantially by depressurizing the CO2-rich absorbent in two steps. The gas from the first step is rich in hydrocarbons and is recycled, only the gas from the second step is vented [116]. A catalytic treatment (e.g., supported Pd/Pt) may be required by environmental regulations to remove hydrocarbons before the CO2 is released to the atmosphere but may also be necessary to ensure the purity of the CO2 for further use