Process for purification by combustion of an effluent that contains carbon dioxide and hydrocarbons

摘要

For the purification of an effluent that contains carbon dioxide and hydrocarbons resulting from a carbon dioxide-assisted recovery stage, the effluent is circulated in a gas-liquid separator (3) to recover C3+ liquid and a gas that contains carbon dioxide and, for example, less than 10% of methane and ethane. Pressurized combustion (13) of the gas with air produced a combustion gas (21) enriched with carbon dioxide and water vapor. The combustion gas (21) is cooled (11) (22) to recover heat, and the cooled combustion gas is recycled under pressure by a compressor (27) to an injection well (29). Nitrogen is at least partly separated from the combustion gas before the recycling, and in an optional intermediate step the condensed water is also separated from the carbon dioxide. The invention has a particular application for the assisted recovery of petroleum by CO2 with a reduction of the greenhouse effect.