System for separating a waste liquid and a hydrocarbon gas from a produced gas
View Patent ↗Produced natural gas containing carbon dioxide is dehydrated and chilled to liquefy the carbon dioxide and then fractionated to produce a waste stream of liquid carbon dioxide and hydrogen sulfide. Natural gas liquids may be first separated and removed before fractionation. After fractionation, the waste stream is pressurized and transmitted to a remote injection well for injection either for disposal of the waste stream and preferably to urge hydrocarbons toward the producing well. A hydrocarbon stream proceeds from fractionation to a methanol absorber system which removes carbon dioxide gas. The hydrocarbon stream is thereafter separated into at least hydrocarbon gas, nitrogen and helium. Some of the nitrogen is reintroduced into a fractionation tower to enhance the recovery of hydrocarbons. A methanol recovery system is provided to recover and reuse the methanol. The hydrocarbons are sold as natural gas and the helium is recovered and sold. Excess nitrogen is vented.
1. A process comprising:
obtaining produced gas from a source of produced gas, said produced gas including hydrocarbon gas and at least carbon dioxide;
cooling the produced gas to essentially liquefy at least a portion of said carbon dioxide to form cooled produced gas;
fractionating the cooled produced gas into said hydrocarbon gas and into said liquefied carbon dioxide;
supplying said hydrocarbon gas as an output; and
supplying said liquefied carbon dioxide as an output.
2. The process of claim 1 wherein said liquefied carbon dioxide is supplied toward an injection well positioned away from said source of produced gas.
3. The process of claim 2 wherein said produced gas is first dehydrated.
4. The process of claim 1 wherein said source of produced gas is a natural gas well.
5. The process of claim 4 wherein said process includes fractionating said cooled produced gas into a first stream which includes said hydrocarbon gas and a second stream which includes said liquefied carbon dioxide.
6. The process of claim 5 wherein said produced gas includes hydrogen sulfide, wherein said second stream includes said hydrogen sulfide.
7. The process of claim 6 wherein said hydrocarbon gas is methane.
8. The process of claim 4 wherein said produced gas includes NGL and wherein said NGL are removed before fractionating said cooled produced gas.
9. A process comprising:
obtaining produced gas from a gas well, said produced gas including hydrocarbon gas and at least carbon dioxide;
dehydrating said produced gas;
cooling the produced gas to liquefy at least a portion of said carbon dioxide to form cooled produced gas;
fractionating the cooled produced gas into said hydrocarbon gas and into said liquefied carbon dioxide;
supplying said hydrocarbon gas as an output; and
supplying said liquefied carbon dioxide as an output.