Process and installation for producing nitrogen and oxygen
First Claim
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1. Process for producing a majority of nitrogen and a minority of oxygen by distilling a gaseous mixture, comprising:
- cooling the gaseous mixture and thereafter introducing it at an intermediate level of a distillation column (4) operating at a medium pressure and equipped with a head condenser (8) and a sump reboiler (9);
vaporizing in the head condenser liquid richer in oxygen than is said gaseous mixture, withdrawn from said column below the introduction point of the gaseous mixture, after expansion (at
19) to a low pressure less than the medium pressure;
withdrawing gaseous nitrogen from the head condenser and reheating it, with a portion thereof being compressed to a high pressure greater than the medium pressure, cooled and introduced into the reboiler (9) to be condensed therein; and
expanding (at
15) at least a portion of the liquid nitrogen thus obtained to the medium pressure and introducing it into the head of the column;
wherein;
said liquid is withdrawn at an intermediate level between the level of gaseous mixture introduction into said column and the reboiler; and
liquid in the sump of the column is vaporized and recovered as a minority product consisting essentially of oxygen.
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Accused Products
Abstract
A column (4) for producing nitrogen comprises, below the air introduction point, a section (17, 18) enriched in oxygen and a sump reboiler (9) supplied by recycled high pressure nitrogen. The expanded liquid (at 19) for supplying the overhead condenser (8) is withdrawn at an intermediate level between the level of air introduction and the reboiler, and the liquid in the sump of the column, after vaporization, constitutes a minority product of the installation consisting essentially of oxygen.
8 Citations
15 Claims
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1. Process for producing a majority of nitrogen and a minority of oxygen by distilling a gaseous mixture, comprising:
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cooling the gaseous mixture and thereafter introducing it at an intermediate level of a distillation column (4) operating at a medium pressure and equipped with a head condenser (8) and a sump reboiler (9); vaporizing in the head condenser liquid richer in oxygen than is said gaseous mixture, withdrawn from said column below the introduction point of the gaseous mixture, after expansion (at
19) to a low pressure less than the medium pressure;withdrawing gaseous nitrogen from the head condenser and reheating it, with a portion thereof being compressed to a high pressure greater than the medium pressure, cooled and introduced into the reboiler (9) to be condensed therein; and expanding (at
15) at least a portion of the liquid nitrogen thus obtained to the medium pressure and introducing it into the head of the column;wherein; said liquid is withdrawn at an intermediate level between the level of gaseous mixture introduction into said column and the reboiler; and liquid in the sump of the column is vaporized and recovered as a minority product consisting essentially of oxygen. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 14)
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9. Installation for producing a majority of nitrogen and a minority of oxygen by distillation of a gaseous mixture, comprising:
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a distillation column (4) operating under a medium pressure and equipped with a head condenser (8) and a sump reboiler (9); means (1, 2, 3,
5) for compressing, purifying and cooling the gaseous mixture and introducing it at an intermediate level into the column;means (16) for withdrawing a liquid richer in oxygen than is said gaseous mixture, at a level of said column lower than the level of introduction of the gaseous mixture, means (19) for expanding this liquid at a low pressure and means for introducing it into the head condenser (8) so as to vaporize it; means (11) for withdrawing nitrogen from the head of the column, and means (6, 3, 7,
14) for reheating, compressing to a high pressure, cooling and introducing into the reboiler (9) a portion of this nitrogen; andmeans (15) for expanding to the medium pressure at least a portion of the liquid nitrogen issuing from the reboiler and for introducing it into the head of the column; wherein the withdrawal level of the said liquid is intermediate between the level of introduction of the gaseous mixture into said column and the reboiler (9); and said installation further comprises means (9, 20, 21, 23 to
26) for vaporizing the liquid in the sump of the column and for recovering the resulting gas, consisting essentially of oxygen, as a minority product of the installation. - View Dependent Claims (10, 11, 12, 13, 15)
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Specification