Nitrogen rejection from natural gas with CO/sub 2/ and variable N/sub 2/ content

Patent · Tue May 29 04:00:00 EDT 1984

OSTI ID:6434965

Vines, H L; Marano, V

A process is described which uses a modified double distillation cycle for rejecting nitrogen from a natural gas stream containing varying amounts of nitrogen, methane, carbon dioxide and ethane-plus hydrocarbons. The natural gas stream is fractionally distilled in the high pressure distillation stage of the double distillation cycle to provide a nitrogen overhead and a bottoms comprising carbon dioxide and ethane-plus hydrocarbons. A sidestream consisting essentially of nitrogen and methane is withdrawn from the high pressure distillation stage as intermediate level feed to the low pressure distillation stage of the double distillation cycle. The nitrogen overhead from the high pressure stage is cooled by heat exchange with the methane bottoms of the low pressure stage which methane bottoms acquires an extra degree of refrigeration from a methane heat pump cycle to provide extra nitrogen reflux to thoroughly remove the carbon dioxide from the natural gas stream in the high pressure stage.

• Assignee: Air Products and Chemical Inc.
• Patent Number(s): US 4451275
• OSTI ID: 6434965
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
030300* -- Natural Gas-- Drilling
Production
& Processing
ALKANES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL HEAT PUMPS
COOLING
DISTILLATION
ELEMENTS
ENERGY SOURCES
ENERGY TRANSFER
ETHANE
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
HEAT PUMPS
HEAT TRANSFER
HYDROCARBONS
METHANE
NATURAL GAS
NITROGEN
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PRESSURE EFFECTS
PROCESSING
REFRIGERATION
REMOVAL
SEPARATION PROCESSES