The invention discloses a process apparatus and method of
nitrogen-containing
natural gas dual-column cryogenic
denitrification. The process apparatus comprises a
denitrification cold box and a high-pressure
denitrification column connected through a pipeline; a bottom outlet of the high-pressure denitrification column, the denitrification cold box and the high-pressure denitrification column areconnected in sequence; an upper outlet of the high-pressure denitrification column, a
heat exchanger, the denitrification cold box and a low-pressure denitrification column are connected in sequence;a top outlet of the low-pressure denitrification column, the denitrification cold box, an
ammonia compressor, a cooler, the denitrification cold box and a top feed port of the low-pressure denitrification column are connected in sequence; a bottom outlet of the low-pressure denitrification column, a fourth
throttle valve, the denitrification cold box, a
product gas compressor and the cooler are connected in sequence. Compared with the prior art, the process apparatus and method have the advantages the
hydrocarbon content in
nitrogen is greatly decreased, the purity of removed
nitrogen is > / =99% by mol; cold is provided for the
system after throttling of denitrified liquid
hydrocarbon, external
coolant circulation is canceled, and
energy consumption of the apparatus is decreased.