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Project Description
The plant is designed to process 25 MMSCFD of gas
containing 0.85 mol-percent of Helium and 31 mol-percent of Nitrogen.
The Cryogenic Unit provides the Cold Box with 60 Mol-percent Methane, a
35 mol-percent nitrogen gas stream, and recovers a high percentage of
ethane as NGL. This is achieved by cooling the inlet gas with the Cold
Box return streams, refrigeration, and expansion in the Turbo-Expander.
The overhead from the Demethanizer is the 60/35 feed to the Cold Box.
The Cold Box utilizes expansion and internal refrigeration to separate
the gas into three product streams that are used for exchange with the
inlet gas. They are the low pressure residue containing less than 2
mol-percent nitrogen, the nitrogen vent containing less than 1.5
mol-percent methane, and the crude helium. The demethanizer operates in
either the ethane recovery or rejection modes producing a residue gas
stream and an NGL stream that meets either a Y-Grade spec or a 205 psig
vapor pressure ethane-plus product. |
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