Removing nitrogen from and subsequently liquefying natural gas stream
A natural gas containing substantial nitrogen is refrigerated to below minus 120/sup 0/F in usual propane-ethylene refrigeration system using a cascade arrangement. Thus, admixed liquid and vapor streams are further refrigerated by heat interchange with bottoms from a fractionation zone into which the feed has been flashed, thus reboiling the fractionation zone bottoms. The nitrogen to be separated and some hydrocarbon, e.g., methane, are taken as overhead from the fractionation zone. The several times flashed fractionation bottoms is substantially at atmospheric pressure and constitutes liquefied natural gas substantially free from nitrogen which is the product of the process. A controls system designed to render the system essentially automatic and to keep it in balanced operation is described. 4 Claims, 1 Drawing Figure (auth)
- Assignee:
- Phillips Petroleum Co.
- Patent Number(s):
- US 3874184
- OSTI ID:
- 7358362
- Resource Relation:
- Patent File Date: Filed date 24 May 1973
- Country of Publication:
- United States
- Language:
- English
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