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US 12,710,228 B2Granted
Method and plant for low temperature fractionation of air
AssigneeLinde Aktiengesellschaft
InventorsDimitri Golubev, Xiaohua Fan
Life of this patent
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Abstract
A SPECTRA process for low-temperature fractionation of air is proposed, in which bottoms liquid from an additional second rectification column used to obtain oxygen is evaporated in a second condenser evaporator arrangement. In this second condenser evaporator arrangement, gas that has been evaporated beforehand in a first condenser evaporator arrangement, which is used for condensation of tops gas from a first rectification column, is partially condensed after recompression. The invention also relates to a corresponding plant.
Claims19
A process for the low-temperature fractionation of air in an air fractionation plant having a first rectification column, a second rectification column, a first condenser evaporator arrangement, and a second condenser evaporator arrangement, wherein the process comprises;
- feeding air into the first rectification column and feeding a stream from the first rectification column into the second rectification column, wherein the first rectification column is operated at a first pressure level and the second rectification column is operated at a second pressure level which is below the first pressure level,
- obtaining a first tops gas stream from the first rectification column as a nitrogen product and discharged the nitrogen product from the air fractionation plant, and obtaining bottoms liquid from the second rectification column as an oxygen product and discharged the oxygen product from the air fractionation plant,
- forming a first material stream and a second material stream, below the first pressure level, in the first condenser evaporator arrangement by evaporating liquid from the first rectification column, and condensing a further tops gas stream from the first rectification column in the first condenser evaporator arrangement and returning the condensed further tops gas stream to the first rectification column as a return flow,
- wherein the first material stream has a first oxygen content, and the second material stream has a second oxygen content which is above the first oxygen content,
- at least part of the first material stream to the first pressure level to form a compressed first material stream and feeding the compressed first material stream, into the first rectification column, and subjecting the at least part of the second material stream to work-performing expansion to form an expanded second material stream and discharging the expanded second material stream, from the air fractionation plant,
- evaporating bottoms liquid from the second rectification column in the second condenser evaporator arrangement,
- after compression, and before being fed into the first rectification column, subjecting at least a part of the compressed first material stream, to partial liquefaction to form a two-phase stream which is fed to form a two-phase stream which is fed into the first rectification column, and
- supplying tops gas of the second rectification column to a work-performing expansion.
5 more elements
An air fractionation plant comprising:
- a first rectification column, a second rectification column, a first condenser evaporator arrangement, and a second condenser evaporator arrangement,
- means for feeding air into the first rectification column, operated at a first pressure level, and means for for feeding a stream from the first rectification column into the second rectification column, operated at a second pressure level which is below the first pressure level,
- means for removing a tops gas stream from the first rectification column and means for discharging the tops gas stream from the air fractionation plant as a nitrogen product, and means for removing a bottoms liquid stream from the second rectification column and discharging the bottoms liquid stream from the air fractionation plant as an oxygen product,
- a first condenser evaporator arrangement for forming a first material stream with a first oxygen content and a second material stream with a second oxygen content above the first oxygen content below the first pressure level by evaporating liquid from the first rectification column, and means for introducing a further tops gas stream from the first rectification column into the first condenser evaporator arrangement to form a condensate and means for returning the condensate to the first rectification column as a return flow,
- means for subjecting the first material stream or a part thereof to compression to the first pressure level and means for feeding the compressed first material stream or the compressed part thereof into the first rectification column, and means for subjecting at least part of the second material stream to expansion to form an expanded second material stream and means for discharging the expanded second material stream from the air fractionation plant,
- a second condenser evaporator arrangement for evaporating bottoms liquid of the second rectification column,
- means for feeding the compressed first material stream into the second condenser evaporator arrangement located upstream of the means for feeding the compressed first material stream into the first rectification column where the compressed first material stream is configured to undergo partial liquefaction to form a two-phase stream, and
- means for subjecting a tops gas stream from the second rectification column to a work-performing expansion.
5 more elements
Dependencies are inferred from the claim text.