MULTIPLE REBOILER, DOUBLE COLUMN, AIR BOOSTED, ELEVATED PRESSURE AIR SEPARATION CYCLE AND ITS INTEGRATION WITH GAS TURBINES

摘要

The present invention is a liquid nitrogen reflux means improvement capable of allowing the operation of conventional dual and triple reboiler air separation cycles at elevated pressures. The improvement comprises: (a) further compressing and cooling another portion of the compressed, essentially impurities free, feed air, thereby producing a further compressed second portion; (b) removing and increasing the pressure of a portion of the liquid oxygen bottoms of the second column and heat exchanging the increased pressure liquid oxygen bottoms against at least a fraction of the further compressed second portion of step (a) so that upon heat exchange the fraction of the further compressed second portion of step (a) is at least partially condensed and the increased pressure liquid oxygen bottoms portion is at least partially vaporized; (c) feeding the at least partially condensed fraction of step (b) to at least one of the two distillation columns; (d) warming the at least partially vaporized oxygen of step (b) to recover refrigeration; (e) compressing a portion of the gaseous nitrogen product and cooling it to a temperature near its condensation temperature by heat exchange against warming process streams; and (f) condensing the cooled, compressed gaseous nitrogen product portion of step (e) and feeding the condensed nitrogen portion as reflux to at least one of the distillation columns.