Process and apparatus for the production of gaseous oxygen under pressure
AssigneeL'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
InventorMaurice Grenier
Life of this patent
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Abstract
In this process for the production of gaseous oxygen under pressure by air distillation in a double column, pumping liquid oxygen withdrawn at the bottom of the low pressure column, and vaporization of compressed liquid oxygen by heat exchange with air at high pressure, all the air to be distilled is compressed at the high air pressure, followed by expanding, at the pressure of the mean pressure column, the excess fraction of this air in a turbine which is decelerated by means of an air booster, and at least one liquid product is withdrawn from the apparatus.
Claims15
Process for production of gaseous oxygen at a pressure higher than approximately 13 bars by air distillation in an apparatus provided with a double column comprising a mean pressure column and a low pressure column, each of said mean and low pressure columns having a respective base and a respective pressure, said process including the steps of:
- i) withdrawing liquid oxygen at the base of said low pressure column;
- ii) pumping said withdrawn liquid oxygen;
- iii) introducing air to be distilled into a heat exchange line, said air being at a first high pressure lower than that at which air condenses by heat exchange with said pumped liquid oxygen, where said pumped liquid oxygen is at a pressure greater than approximately 13 bars, said first pressure being at least equal to approximately 30 bars;
- iv) vaporizing said pumped liquid oxygen by heat exchange with said air in said heat exchange line, to produce gaseous oxygen at a pressure higher than approximately 13 bars;
- v) withdrawing a portion of said air from said line, said portion being surplus to refrigerating needs of said line;
- vi) expanding said portion to the pressure of said mean pressure column at an intermediate cooling temperature in a turbine, said turbine being slowed down by a first compressor, said compressor being used in step iii) to pressurize all the air to be distilled to said first high pressure;
- and
- vii) withdrawing an amount of at least one liquid product from said apparatus as a final product.
Process for the production of gaseous oxygen at a pressure of at least approximately 13 bars, by introducing air to be distilled in an apparatus provided with a double column comprising a low pressure column and a mean pressure column, said mean pressure column having a pressure, including pumping of liquid oxygen which is withdrawn at the bottom of the low pressure column, and vaporization of the pumped liquid oxygen compressed by heat exchange with air pressurized to a high pressure which is substantially higher than the pressure of the mean pressure column, wherein said process comprises the steps of:
- i) compressing all the air to be distilled to a first high pressure which is considerably higher than the pressure of the mean pressure column;
- ii) cooling a first fraction of the compressed air;
- iii) expanding at an intermediate cooling temperature at least a portion of said first cooled fraction to the pressure of the mean pressure column in a turbine before introducing same into the double column;
- iv) boosting any remaining compressed air at the first high pressure to a second high pressure, said second high pressure being lower than at least one of (a) that pressure at which air condenses and (b) that pressure at which air pseudo-condenses, by heat exchange with oxygen vaporizing at the oxygen pressure of at least 13 bars, said second high pressure being at least equal to approximately 30 bars, and also, being selected so that one of air condensation and air pseudo-condensation at the second high pressure takes place at approximately the inlet temperature of the turbine;
- v) cooling and liquefying at least a portion of the boosted air, the flow rate of which is lower than the flow rate of liquid oxygen to be vaporized;
- vi) expanding said liquefied portion of air and introducing said expanded air into the double column;
- and
- vii) withdrawing at least one liquid product from the apparatus as a final product.
Dependencies are inferred from the claim text.