Process for eliminating oxygen from a gas containing carbon dioxide so an industrial exhaust gas can be injected into an oil well to assist recovering of oil

摘要

Providing a process for eliminating oxygen from a gas containing carbon dioxide so an industrial exhaust gas can be injected into an oil well to assist recovering of oil. The process involves: (a) burning the gas with hydrocarbons in catalytic combustion zone(s) (5); (b) recovering exhaust gases comprising mostly carbon dioxide (CO2), some water and effectively no oxygen (O2); (c) cooling these gases in heat exchanger(s) (4, 10, 11, 12); and (d) condensing the cooled gases in condenser(s) (13) to recover water (line 14) and a gaseous effluent (line 15) which effectively contains no oxygen. The gas contains molecular nitrogen which is separated out before combustion or after condensation. The effluent from the condensation stage or from the nitrogen separation stage is introduced into an oil well to assist recovery of oil. The O2 content of the gas containing CO2 is between 0.1 and 30% by weight and preferably between 0.5 and 20 %. The hydrocarbon flow mixed with the gas to be treated in the combustion zone contains between and 30 carbon atoms and preferably between 1 and 10. The gas containing CO2 is preheated before entering the combustion zone to a temperature of between 100 and 600 deg C and preferably between 300 and 50 deg C. The catalyst in the combustion zone is in the form of pellets or extrusions containing a noble metal of the platinum family. The gas containing CO2 is compressed before entering the combustion zone to a pressure of between 2 and 30 bars and preferably between 2 and 10 bars. The gas containing CO2 also contains hydrogen sulfide (H2S) which is recovered as sulfur dioxide with the condensed water from the condensers. The preheating stage is carried out using indirect heat exchange with the effluents from the combustion zone. The nitrogen separation stage is carried out before combustion using cryogenic distillation. The catalyst is on a honeycomb support with the combustion occurring inside the multiple channels through the support. Water is removed before the nitrogen separation stage.