초록 ▼

A process for separating the components of a multi-component gas stream is disclosed. The multi-component gas stream is contacted with a solvent in an extractor to produce an overhead stream enriched with unabsorbed component(s) and a rich solvent bottoms stream enriched with absorbed component(s).

A process for separating the components of a multi-component gas stream is disclosed. The multi-component gas stream is contacted with a solvent in an extractor to produce an overhead stream enriched with unabsorbed component(s) and a rich solvent bottoms stream enriched with absorbed component(s). The rich solvent bottoms stream is then flashed at reduced pressure to regenerate lean solvent and to recover the absorbed component(s) as an overhead stream. The regenerated solvent is recycled to the extractor. A portion of the circulating solvent comprises external solvent added to the system. A second portion of the circulating solvent comprises internal solvent contained in the feed gas.

대표청구항 ▼

What is claimed is: 1. A process for separating the components of a multi-component gas stream, the process comprising: contacting the multi-component gas stream with a lean solvent in an extractor to produce an overhead stream that is enriched in at least one unabsorbed component gas and a rich so

What is claimed is: 1. A process for separating the components of a multi-component gas stream, the process comprising: contacting the multi-component gas stream with a lean solvent in an extractor to produce an overhead stream that is enriched in at least one unabsorbed component gas and a rich solvent bottoms stream that is enriched in at least one absorbed component gas; flashing the rich solvent bottoms stream in at least one reduced pressure stage to regenerate lean solvent and to produce an overhead product stream that is enriched in at least one absorbed component gas, wherein the reduced pressure stage comprises two or more flash vessels of which at least one is a surge vessel and wherein level control instrumentation for the extractor and flash vessels is aligned such as to allow the surge vessel to be close to the middle of the sequence of vessels to improve control; and recycling the regenerated lean solvent to the extractor. 2. The process of claim 1, wherein the multi-component gas stream comprises at least one hydrocarbon. 3. The process of claim 1, wherein the multi-component gas stream comprises one or more components selected from the group consisting of hydrogen, nitrogen, helium, argon, methane, ethylene, ethane, heavier saturated and unsaturated hydrocarbons and mixtures thereof. 4. The process of claim 1, wherein the multi-component gas stream comprises natural gas, coal gas, refinery gas or gas from chemical plants. 5. The process of claim 1, wherein the unabsorbed component gas comprises nitrogen. 6. The process of claim 1, wherein the unabsorbed component gas comprises hydrogen. 7. The process of claim 1, wherein the product stream comprises methane. 8. The process of claim 1, wherein the lean solvent comprises one or more of the components of the multi-component gas stream. 9. The process of claim 1, wherein the external solvent is selected from the group consisting of paraffinic solvents, naphthenic solvents, aromatic solvents and specially mixed solvents. 10. The process of claim 1, wherein the extractor is a tower with internals to promote mass transfer. 11. The process of claim 1, wherein the multi-component gas stream is counter-currently contacted with the lean solvent. 12. The process of claim 1, wherein the lean solvent is chilled to a temperature as cold as-40° F. (-40° C.). 13. The process of claim 1, wherein the lean solvent is cooled to a temperature as cold as-185° F. (-121° C.). 14. The process of claim 1, wherein the level control instrumentation comprises valves. 15. The process of claim 1, wherein the level control instrumentation comprises hydraulic turbines. 16. The process of claim 1, wherein a volume of rich solvent retained in the flash vessel is included to allow temporary accumulation of a contaminant in the rich solvent thereby allowing a product vapor to remain below a required specification. 17. The process of claim 16, wherein additional solvent volume is added to increase ability to accommodate contaminants. 18. The process of claim 16, wherein the external solvent comprises a solvent chosen for its ability to selectively hold a contaminant in the solvent. 19. The process of claim 16, wherein the external solvent comprises sulfinol, selexol, an amine compound, a glycol compound, or a morpholine compound. 20. The process of claim 16, wherein the contaminant comprises carbon dioxide, hydrogen sulfide, mercaptans, oxygen, water, or carbon monoxide. 21. The process of claim 16, wherein the operating pressure of the flash vessels is increased to reduce vaporization of a contaminant. 22. The process of claim 1 further comprising a purification step to further purify the overhead unabsorbed component gas, the flashed overhead product stream, or both. 23. The process of claim 22, wherein an absorber/regeneration system employing a circulating solvent is used in the purification step. 24. The process of claim 22, wherein adsorption, membrane, incineration or other technologies are used in the purification step. 25. The process of claim 1, wherein the pressure of the last flash vessel is below atmospheric pressure. 26. The process of claim 1, wherein at least one reduced pressure stage is conducted at below atmospheric pressure. 27. The process of claim 1 for separating the components of a multi-component gas stream, wherein: the step of contacting the multi-component gas stream with a lean solvent occurs at a temperature of about-6.7° C. to about-40° C. in an extractor to produce an overhead stream that is enriched in at least one unabsorbed component gas and a rich solvent bottoms stream that is enriched in at least one absorbed component gas; flashing the rich solvent bottoms stream in at least one reduced pressure stage to regenerate lean solvent and to produce an overhead product stream that is enriched in at least one absorbed component gas, wherein the reduced pressure stage comprises two or more flash vessels of which at least one is a surge vessel and a wherein level control instrumentation for the extractor and flash vessels is aligned such as to allow the surge vessel to be close to the middle of the sequence of vessels; recycling the regenerated lean solvent comprising absorbed heavy components that do not flash from the rich solvent to the extractor; and adding an external solvent to the regenerated lean solvent forming a circulating solvent stream that contains both external solvent and heavy components. 28. The process of claim 1 wherein the lean solvent is internal solvent or external solvent. 29. The process of claim 27, wherein a volume of rich solvent retained in the flash vessel is included to allow temporary accumulation of a contaminant in the rich solvent thereby allowing a product vapor to remain below a required specification. 30. The process of claim 29, wherein additional solvent volume is added to increase ability to accommodate contaminants. 31. The process of claim 1 further comprising a purification step to further purify the overhead unabsorbed component gas, the flashed overhead product stream, or both. 32. The process of claim 31, wherein an absorber/regeneration system employing a circulating solvent is used in the purification step.