METHOD AND DEVICE FOR THE LOW-TEMPERATURE SEPARATION OF AIR AT VARIABLE ENERGY CONSUMPTION
First Claim
1. Method for variably obtaining a pressurized-gas product by means of the low-temperature separation of air in a distillation column system, which has a high-pressure column and a low-pressure column, in whichthe entire feed air is compressed in a main air compressor to a first pressure, which is at least 4 bar higher than the operating pressure of the high-pressure column,a first partial stream of the feed air compressed in the main air compressor is cooled down to an intermediate temperature in a main heat exchanger and expanded in a first air turbine in such a way that work is performed,at least a first part of the work-performing expanded first partial stream introduced into the distillation column system,a second partial stream of the feed air compressed in the main air compressor is recompressed to a second pressure, which is higher than the first pressure, in a first booster air compressor, which in particular is driven by the first turbine, cooled down in the main heat exchanger and subsequently expanded and introduced into the distillation column system,a first product stream is removed in a liquid form from the distillation column system and subjected to a pressure increase to a first product pressure,the first product stream is evaporated or pseudo-evaporated under the first product pressure and warmed up in the main heat exchanger,the warmed-up first product stream is obtained as the first pressurized-gas product,a first process stream, which contains at least 78 mol % of nitrogen, is compressed in a multi-stage compressor from an inlet pressure to a final pressure,the multi-stage compressor being formed by a nitrogen product compressor andthe first process stream being formed by a first gaseous nitrogen stream from the low-pressure column,at least for a time a second process stream, which contains at least 78 mol % of nitrogen, is mixed with the first process stream downstream of the first stage of the multi-stage compressor, the second process stream being formed by first gaseous nitrogen stream from the high-pressure column,in a first operating mode, a first amount of first pressurized-gas product is obtained,in a second operating mode, a second amount of first pressurized-gas product, which is smaller than the first amount, is obtained,in the first operating mode, a first amount of the second process stream, which may even be zero, is compressed in the multi-stage compressor andin the second operating mode, a second amount of the second process stream, which is greater than the first amount of the second process stream, is compressed in the multi-stage compressor.
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Abstract
A method and a device used to variably obtain a compressed-gas product by means of the low-temperature separation of air in a distillation column system. In a first operating mode, a first amount of first compressed-gas product is obtained, and, in a second operating mode, a second, smaller amount is obtained. In the first operating mode, a first amount of high-pressure column nitrogen is compressed in a nitrogen compressor and in the second operating mode, a second, larger amount is compressed in the nitrogen compressor.
2 Citations
10 Claims
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1. Method for variably obtaining a pressurized-gas product by means of the low-temperature separation of air in a distillation column system, which has a high-pressure column and a low-pressure column, in which
the entire feed air is compressed in a main air compressor to a first pressure, which is at least 4 bar higher than the operating pressure of the high-pressure column, a first partial stream of the feed air compressed in the main air compressor is cooled down to an intermediate temperature in a main heat exchanger and expanded in a first air turbine in such a way that work is performed, at least a first part of the work-performing expanded first partial stream introduced into the distillation column system, a second partial stream of the feed air compressed in the main air compressor is recompressed to a second pressure, which is higher than the first pressure, in a first booster air compressor, which in particular is driven by the first turbine, cooled down in the main heat exchanger and subsequently expanded and introduced into the distillation column system, a first product stream is removed in a liquid form from the distillation column system and subjected to a pressure increase to a first product pressure, the first product stream is evaporated or pseudo-evaporated under the first product pressure and warmed up in the main heat exchanger, the warmed-up first product stream is obtained as the first pressurized-gas product, a first process stream, which contains at least 78 mol % of nitrogen, is compressed in a multi-stage compressor from an inlet pressure to a final pressure, the multi-stage compressor being formed by a nitrogen product compressor and the first process stream being formed by a first gaseous nitrogen stream from the low-pressure column, at least for a time a second process stream, which contains at least 78 mol % of nitrogen, is mixed with the first process stream downstream of the first stage of the multi-stage compressor, the second process stream being formed by first gaseous nitrogen stream from the high-pressure column, in a first operating mode, a first amount of first pressurized-gas product is obtained, in a second operating mode, a second amount of first pressurized-gas product, which is smaller than the first amount, is obtained, in the first operating mode, a first amount of the second process stream, which may even be zero, is compressed in the multi-stage compressor and in the second operating mode, a second amount of the second process stream, which is greater than the first amount of the second process stream, is compressed in the multi-stage compressor.
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10. A device for variably obtaining a pressurized-gas product by means of the low-temperature separation of air with
a distillation column system, which has a high-pressure column and a low-pressure column, a main air compressor for compressing the entire feed air to a first pressure, which is at least 4 bar higher than the operating pressure of the high-pressure column, means for cooling down a first partial stream of the feed air compressed in the main air compressor to an intermediate temperature in a main heat exchanger, a first air turbine for expanding the cooled-down first partial stream in such a way that work is performed, means for introducing the work-performing expanded first partial stream into the distillation column system, a first booster air compressor for recompressing a second partial stream of the feed air compressed in the main air compressor to a second pressure, which is higher than the first pressure, the booster air compressor particular being driven by the first turbine, is recompressed, means for cooling down the recompressed second partial stream in the main heat exchanger cooled down, means for expanding the cooled-down second partial stream and introducing it into the distillation column system, means for removing a first product stream in a liquid form from the distillation column system removed and for increasing the pressure of the liquid first product stream to a first product pressure, means for evaporating or pseudo-evaporating and warming up the first product stream under the first product pressure in the main heat exchanger, means for obtaining the warmed-up first product stream as the first pressurized-gas product, a multi-stage compressor for compressing a first process stream, which contains at least 78 mol % of nitrogen, from an inlet pressure to a final pressure, the multi-stage compressor being formed by a nitrogen product compressor and the first process stream being formed by a first gaseous nitrogen stream from the low-pressure column, means for mixing a second process stream, which contains at least 78 mol % of nitrogen, with the first process stream downstream of the first stage of the multi-stage compressor, the second process stream being formed by first gaseous nitrogen stream from the high-pressure column, means for switching over between a first operating mode and a second operating mode, in the first operating mode, a first amount of pressurized-gas product being obtained, in a second operating mode, a second amount of first pressurized-gas product, which is smaller than the first amount, being obtained and the means for switching over between the first operating mode and the second operating mode being formed such that in the first operating mode, a first amount of the second process stream, which may even be zero, is compressed in the multi-stage compressor from an inlet pressure to a final pressure and in the second operating mode, a second amount of the second process stream, which is greater than the first amount of the second process stream, is compressed in the multi-stage compressor.
Specification