Method of processing gas associated with oil

Abstract

The invention relates to a method for producing combustible gas for gas engines from associated gas obtained during oil production, the associated gas containing methane, ethane, propane, hydrocarbons having more than three carbon atoms, and optionally propene, wherein a gaseous fraction and a liquid fraction are obtained by partially condensing the associated gas, wherein the condensation process is performed under such pressure and temperature conditions that the liquid phase is substantially free from methane, ethane, propane, and optionally propene, and that substantially the entire methane, ethane, propane, and optionally propene are contained in the gaseous phase.

1 . A method of producing combustible gas for gas engines from associated gas which is produced in crude oil production and which contains methane, ethane, propane, hydrocarbons having more than three carbon atoms and optionally propene, wherein a gaseous fraction and a liquid fraction are obtained by partially condensing the associated gas, characterized in that the condensation process is performed under such pressure and temperature conditions that the liquid phase is substantially free from methane, ethane, propane and optionally propene, and substantially the entire methane, ethane, propane and optionally propene is contained in the gaseous phase. 
     
     
         2 . A method as set forth in  claim 1  characterized in that the condensation process is performed at a temperature of between −5 degrees Celsius and −14 degrees Celsius. 
     
     
         3 . A method as set forth in  claim 2  characterized in that the condensation process is performed at a temperature of between −7 degrees Celsius and −12 degrees Celsius. 
     
     
         4 . A method as set forth in  claim 1  characterized in that the condensation process is effected in a plurality of stages, wherein cooling is effected to a temperature of between −5 and −8 degrees Celsius in one stage and to a temperature of between −8 and −12 degrees Celsius in a further stage. 
     
     
         5 . A method as set forth in  claim 1  characterized in that the pressure in the condensation process is between 1 bar and 16 bars, preferably between 10 bars and 16 bars, particularly preferably between 14 bars and 16 bars. 
     
     
         6 . A method as set forth in  claim 1  characterized in that the gaseous fraction has a methane number of at least 40, preferably at least 45. 
     
     
         7 . A method as set forth in  claim 1  characterized in that the gaseous phase is substantially free from n-butane and isobutane. 
     
     
         8 . A method as set forth in  claim 1  characterized in that water vapor which is possibly present in the associated gas is removed. 
     
     
         9 . A method as set forth in  claim 8  characterized in that the water vapor is removed by condensation, absorption or combinations thereof.