This Nitrogen Rejection Unit (NRU) is used to process raw natural gas or methane-rich gas from mining. It consists of three parallel trains to remove nitrogen from natural gas feedstock which has nitrogen composition varying from 2% to 80%. Each train has a compression column to reduce the temperature of the feed gas to a point where methane is liquefied and nitrogen is still of gas phase. A series of heat exchangers are used for distillation. The plant is capable of producing several combinations of product stream as follows:
(a). Nitrogen, methane-rich sales gas, and natural gas liquids. Ethane may be recovered in the sales gas or in the liquid product.
(b). Methane-rich sales gas and natural gas liquids from low percentage nitrogen feeds. Ethane may be recovered in the sales gas or in the liquid product.
(c). Nitrogen and methane-rich sales gas. Natural gas liquids removal is performed to the extent necessary to meet a maximum dew point specification for the sales gas.