Process and apparatus for the production of low pressure gaseous oxygen

In a process for the production of gaseous oxygen (“GOX”), said process comprising:

• cooling and at least partially condensing feed air (1) by heat exchange using heat exchange means (E1) having a warm end and a cold end to produce cooled and at least partially condensed feed air (2);
• distilling said cooled and at least partially condensed feed air (2) in a distillation column system (C1, C2) to produce liquid oxygen (“LOX”) product;
• removing a stream (8) of said LOX product from the distillation column system (C1, C2) and vaporizing said LOX product stream (8) by heat exchange (E1) against the feed air (1) to produce GOX;
• and
• separately from the LOX product, vaporizing LOX refrigerant (10) from an external source by heat exchange (E1) against the feed air (1) to produce vaporized refrigerant (11) thereby providing a portion of the refrigeration duty required to cool and at least partially condense the feed air;
• the improvement consisting of injecting the LOX refrigerant into the heat exchange means (E1) either:
• (a) at a pressure greater than that of the LOX product entering the heat exchange means;
• or
• (b) at a pressure substantially equal to that of the LOX product entering the heat exchange means and at an intermediate point between the warm and cold ends where the temperature of the heat exchange means (E1) is above the boiling temperature of the LOX refrigerant.