Process and installation for producing high-pressure nitrogen

摘要

A method and apparatus for producing high pressure nitrogen is provided. This system includes a first compressor for compressing air and cooling air to substantially the dew-point, a high pressure column, a medium pressure column, a conduit for introducing at least a portion of the compressed air at a base of the high pressure column; a conduit for removing a oxygen enriched liquid from the base of the high pressure column; a first valve for reducing the pressure of the oxygen enriched liquid to a medium pressure, where the medium pressure is between the high pressure and atmospheric pressure, a conduit for introducing the oxygen enriched liquid at an intermediate place of the medium pressure column; a second expander for reducing the pressure of at least a part of the liquid removed from the base of the medium pressure distillation column, to a low pressure to cool a top condenser of the medium pressure column and to form a waste vapor stream; a cold compressor for compressing a vapor stream removed form the medium pressure column, cooling the compressed vapor stream, and introducing it into the base of the high pressure column; a heat exchanger for heating the waste vapor stream, a first expander for expanding the heated stream to produce power; a conduit for withdrawing liquid from the top of the medium pressure column, pump for pumping the withdrawn liquid to high pressure and injecting it at the top of the high pressure column; and conduit for withdrawing product nitrogen from the top of the high pressure column.

主权项

1. A process for producing high pressure nitrogen, the process comprising:
cooling feed air to substantially the dew-point thereof; introducing at least a portion of said feed air at a base of a high pressure column; removing an oxygen enriched liquid from the base of said high pressure column; reducing the pressure of said oxygen enriched liquid in a first valve to a medium pressure; wherein said medium pressure is between said high pressure and atmospheric pressure; introducing said oxygen enriched liquid at an intermediate place of a medium pressure column; reducing the pressure of at least a part of a liquid removed from the base of said medium pressure column in a second valve to a low pressure to cool a top condenser of said medium pressure column and to form a waste vapor stream; compressing a vapor stream removed form the medium pressure column in a cold compressor, cooling said vapor stream, and introducing the vapor stream into the base of the high pressure column; heating said waste vapor stream, and expanding said waste vapor stream in an expander to produce power, withdrawing a top liquid from the top of said medium pressure column; pumping said top liquid to said high pressure and injecting it at the top of the high pressure column; and withdrawing product nitrogen from the top of the high pressure column.