Refrigeration – Cryogenic treatment of gas or gas mixture – Separation of gas mixture
Patent
1998-03-23
1999-09-21
Kilner, Christopher B.
Refrigeration
Cryogenic treatment of gas or gas mixture
Separation of gas mixture
62654, 62913, F25J 304
Patent
active
059539372
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a process and an apparatus for the variable production of a gaseous pressurized product by low-temperature separation of air by means of pressure elevation in the liquid state and subsequent evaporation.
BACKGROUND OF THE INVENTION
The method of pressurizing a liquid product of an air separator and then evaporating it is frequently also termed "internal compression". Processes of this type have long been known for the production of a constant rate of a pressurized gas (for example DE-C-752439) and offer the advantage of lower apparatus costs in comparison with the gaseous product compression.
"Alternating reservoir processes" having at least two reservoir tanks are likewise known, in which variable rates of an atmospheric gas can be produced under atmospheric pressure and, nevertheless, steady-state operation of the rectification is possible (see, for example, W. Rohde, Linde-Berichte aus Technik und Wissenschaft, 54/1984, pages 18 to 20).
The publications DE-B-1056633, EP-A422974, EP-A-524785 and EP-A-556861 indicate processes which combine internal compression and alternating reservoir storage by buffering in reservoir tanks both the liquid product to be evaporated and the heat-transport medium (air or nitrogen) liquefied in the evaporation. The problem of the varying requirement of heat-transport medium for the evaporation of the liquid product is solved in DE-B-1056633 by expanding, so as to perform work, the respective portion of the heat-transport medium which is not required for the evaporation and discarding it. Later processes moved away from this and, instead, variable amounts of heat-transport medium are compressed (EP-A-422974, EP-A-524785 and EP-A-556861). Whereas in the first case a purified gas is lost unused, in the second case large relative fluctuations of the compressor throughput occur. The two types of plant can only be run in the respective operating mode.
The object therefore underlying the invention is to specify a process and an apparatus which can be operated as flexibly as possible and which avoid, in particular, the above-described disadvantages.
BRIEF DESCRIPTION OF THE DRAWING
The attached drawing is a schematic flow-sheet of a comprehensive embodiment of the invention.
SUMMARY OF THE INVENTION
This object is achieved by the a process for the variable production of a gaseous pressurized product (3) by low-temperature separation of air, in which feed air (10, 13) is fed to a rectifying system (14, 15), buffered in a first reservoir tank (33), elevated pressure by indirect heat exchange (12) and obtained as gaseous pressurized product (37), in addition, a cycle compressor (41, 42), the cycle compressor (41, 42) being fed to the indirect heat exchange (12) to evaporate the liquid fraction (36) and being, at least in part, liquefied, in the cycle compressor (41, 42) being expanded (43) so as to perform work and reservoir tank (49).
The product to be produced in gaseous and pressurized form is drawn off in liquid form from the or one of the rectifying columns and buffered in a first reservoir tank. Depending on whether, at that moment, a below-average or an above-average product rate is being produced, the liquid level in the tank rises or falls. For example, the amount of liquid fraction produced in the rectification which cannot at that moment be evaporated or otherwise used (for example as liquid product) can be introduced into the tank; correspondingly, at high product demand, liquid is conducted from the tank to the evaporator. However, it is also possible to introduce the entire liquid fraction into the reservoir tank and to take off the amount actually required each time and feed to the evaporator. Under "reservoir tank" any apparatus for the storage of a liquid is to be understood. This can be an external tank with his own insulation, or another kind of vessel, which is located inside the low-temperature apparatus and capable of storing liquid.
Any known method can be employed for pressure elevation in the liquid sta
REFERENCES:
patent: 2708831 (1955-05-01), Wilkinson
patent: 3058315 (1962-10-01), Schuftan
patent: 3485053 (1969-12-01), Grenier
patent: 4529425 (1985-07-01), McNeil
patent: 5084081 (1992-01-01), Rhode
patent: 5209070 (1993-05-01), Darredeau
patent: 5252149 (1993-10-01), Mostello et al.
patent: 5386692 (1995-02-01), Laforce
patent: 5412953 (1995-05-01), Darredeau et al.
patent: 5526647 (1996-06-01), Grenier
W. Rohde, "Luftzerlegungsanlage mit Wechselspeicherung fur variable Sauerstofflieferung", Linde Berichte Aus Technik Und Wissenschaft, No. 54, pp. 18-20, 1984.
Altmeyer Horst
Corduan Horst
Kilner Christopher B.
Linde Aktiengesellschaft
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