Processes and Device for Low Temperature Separation of Air
First Claim
1. A process for the low-temperature separation of air with a distillation-column system comprising at least one separation column, said process comprising:
- compressing a main air stream in an air compressor at a first pressure and purifying the main air stream in a purification device;
compressing a first air stream, which is formed from at least one portion of the purified main air stream, in a recompressor at a second pressure that is higher than the first pressure;
branching off a throttling stream and a turbine steam from the further compressed first air stream;
cooling the throttling stream and liquefying or pseudo-liquefying the throttling stream in a main heat exchanger and passing the throttling stream to an expansion equipment;
conducting the expanded throttling stream into the distillation-column system;
cooling the turbine stream in the main heat exchanger and, under an intermediate temperature of the main heat exchanger, conducting the turbine stream into an expansion machine and expanding the turbine stream to produce work;
conducting the expanded turbine stream at least in part into the distillation-column system;
taking off a liquid product stream from the distillation-column system at an increased pressure and vaporizing or pseudo-vaporizing the liquid product stream by indirect heat exchange with the throttling stream and drawing off as a gaseous product stream,wherein the turbine stream is cooled so that, if the pressure of the turbine stream is subcritical, the dewpoint temperature or a lower temperature is attained, or, if the pressure of the turbine stream is subcritical, the turbine stream is pseudo-liquefied,wherein the cooled-down or pseudo-liquefied turbine stream is expanded at least at the dewpoint temperature at an intermediate pressure that is below the second pressure, andwherein the turbine stream expanded at the intermediate pressure is heated up in the main heat exchanger at the intermediate temperature before it is conducted to an expansion machine.
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Accused Products
Abstract
The process and device serve for the low-temperature separation of air in a distillation-column system includes at least one separation column. A main air stream is compressed in an air compressor at a first pressure and is then purified. A first air stream, which is formed from at least one part of the purified main air stream, is further compressed at a second pressure that is higher than the first pressure. From the further compressed first air stream, a throttling stream and a turbine stream are branched off. The throttling stream is cooled down and liquefied or pseudo-liquefied in a main heat exchanger and is then passed on to expansion equipment. The expanded throttling stream is conducted into the distillation-column system. The turbine stream is cooled down in the main heat exchanger and under an intermediate temperature of the main heat exchanger is conducted into an expansion machine.
10 Citations
14 Claims
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1. A process for the low-temperature separation of air with a distillation-column system comprising at least one separation column, said process comprising:
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compressing a main air stream in an air compressor at a first pressure and purifying the main air stream in a purification device; compressing a first air stream, which is formed from at least one portion of the purified main air stream, in a recompressor at a second pressure that is higher than the first pressure; branching off a throttling stream and a turbine steam from the further compressed first air stream; cooling the throttling stream and liquefying or pseudo-liquefying the throttling stream in a main heat exchanger and passing the throttling stream to an expansion equipment; conducting the expanded throttling stream into the distillation-column system; cooling the turbine stream in the main heat exchanger and, under an intermediate temperature of the main heat exchanger, conducting the turbine stream into an expansion machine and expanding the turbine stream to produce work; conducting the expanded turbine stream at least in part into the distillation-column system; taking off a liquid product stream from the distillation-column system at an increased pressure and vaporizing or pseudo-vaporizing the liquid product stream by indirect heat exchange with the throttling stream and drawing off as a gaseous product stream, wherein the turbine stream is cooled so that, if the pressure of the turbine stream is subcritical, the dewpoint temperature or a lower temperature is attained, or, if the pressure of the turbine stream is subcritical, the turbine stream is pseudo-liquefied, wherein the cooled-down or pseudo-liquefied turbine stream is expanded at least at the dewpoint temperature at an intermediate pressure that is below the second pressure, and wherein the turbine stream expanded at the intermediate pressure is heated up in the main heat exchanger at the intermediate temperature before it is conducted to an expansion machine. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A device for the low-temperature separation of air with a distillation-column system having at least one separation column, comprising:
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an air compressor for compressing a main air stream at a first pressure; a purification device for purifying the main air stream compressed at the first pressure; a recompressor for compressing a first air stream, which is formed from at least one portion of the purified main air stream, at a second pressure that is higher than the first pressure; means for branching off a throttling stream and a turbine stream from the cooled, further compressed first air stream; a main heat exchanger for cooldown of the throttling stream and the turbine stream; means for liquefying or pseudo-liquefying the throttling stream in the main heat exchanger; expansion equipment for expanding the liquefied or pseudo-liquefied throttling stream; means for conducting the expanded throttling stream into the distillation-column system; means for conducting the turbine stream under an intermediate temperature of the main heat exchanger into an expansion machine for expansion of the turbine stream to produce work; means for conducting the turbine stream, expanded to produce work, into the distillation-column system; means for offtake of a liquid product stream from the distillation-column system, for an increase in its pressure in a liquid state to an increased pressure, and for vaporization under this increased pressure by indirect heat exchange with the throttling stream; means for drawing off the (pseudo-)vaporized product stream as a gaseous product stream; means for drawing off the turbine stream from the main heat exchanger at a position at which, in the operation of the device, if the pressure of the turbine stream is subcritical, roughly the dewpoint temperature of the turbine stream or a lower temperature is attained, or if the pressure of the turbine stream is subcritical, the turbine stream is pseudo-liquefied; means for expanding the turbine stream drawn off from the main heat exchanger at an intermediate pressure that lies below the second pressure; and means of heating up the turbine stream expanded at the intermediate pressure, in the main heat exchanger to the intermediate temperature, in which said means is downstream of the expansion machine.
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13. A process for the low-temperature separation of air, comprising:
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compressing a main air stream to a first pressure; purifying the main air stream; forming a first air stream from at least one portion of the purified main air stream; compressing the first air stream to a second pressure that is higher than the first pressure; branching off a throttling stream and a turbine steam from the compressed first air stream; liquefying or pseudo-liquefying the throttling stream in a main heat exchanger; cooling the turbine stream in the main heat exchanger so far that, if the pressure of the turbine stream is subcritical, the dewpoint temperature or a lower temperature is attained, or, if the pressure of the turbine stream is subcritical, the turbine stream is pseudo-liquefied; expanding the cooled or pseudo-liquefied turbine stream to an intermediate pressure that is below the second pressure; heating the turbine stream expanded at the intermediate pressure in the main heat exchanger is heated up at the intermediate temperature; conducting the heated expanded turbine stream at the intermediate pressure to an expansion machine and conducting at least a part of the further expanded turbine stream to a distillation-column system; and taking a liquid product stream off from the distillation-column system, bringing the liquid product stream to an increased pressure, vaporizing or pseudo-vaporizing the liquid product stream by indirect heat exchange with the throttling stream and drawn off as a gaseous product stream.
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14. A device for the low-temperature separation of air, comprising:
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an air compressor for compressing a main air stream; a purification device for purifying the compressed main air stream; a recompressor for compressing a first air stream, formed from at least one portion of the purified main air stream; a line for branching off a throttling stream and a turbine stream from the compressed first air stream; a main heat exchanger for cooling the throttling stream and the turbine stream, thereby liquefying or pseudo-liquefying the throttling stream; an expansion equipment for expanding the liquefied or pseudo-liquefied throttling stream; a line for conducting the expanded throttling stream into a distillation-column system; a line for drawing off the turbine stream from the main heat exchanger; an expansion machine for expanding the turbine stream drawn off from the main heat exchanger to an intermediate pressure; a line for conducting the expanded turbine stream at intermediate pressure to the main heat exchanger to heat to an intermediate temperature; a line for conducting the turbine stream under an intermediate temperature to an expansion machine; a line for conducting the expanded turbine stream into the distillation-column system; a line for conducting a liquid product stream from the distillation-column system, and having a pump to increase its pressure in a liquid state, and for vaporization in the main heat exchanger with the throttling stream; and a line for drawing off the (pseudo-)vaporized product stream as a gaseous product stream.
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Specification