Refrigeration – Cryogenic treatment of gas or gas mixture – Separation of gas mixture
Utility Patent
1999-04-30
2001-01-02
Capossela, Ronald (Department: 3744)
Refrigeration
Cryogenic treatment of gas or gas mixture
Separation of gas mixture
C062S905000, C062S907000, C062S654000
Utility Patent
active
06167723
ABSTRACT:
The present invention relates to an installation for the distillation of air of the type comprising a medium pressure column, a low pressure column and a vaporizer-condensor for placing in heat exchange relation a calorigenic gas with a liquid from the low pressure column.
The invention is applicable particularly to supplying impure oxygen, for example for the supply of blast furnaces in ferrous metallurgical industry.
To ensure such a supply of impure oxygen, it is known to use an installation of the type mentioned above which comprises moreover a mixing column. Such a mixing column operates under a pressure substantially equal to or lower than the medium pressure. It is supplied at its base with a gas such as purified and compressed air and at its head with a liquid more volatile than the gas, such as impure liquid oxygen from the base of the low pressure column and brought by pumping to the pressure of the mixing column. There is withdrawn from the head of such a mixing column impure gaseous oxygen to be supplied substantially at the pressure of the mixing column.
Generally, the low pressure column is above the vaporizer-condenser, which itself is above the medium pressure column. The double column thus comprises a single upright structure and the mixing column is disposed beside the double column. This arrangement of the double column permits prefabrication in the plant of the installation in a limited number of cold boxes or packages of which a principal package comprises the double column. These packages are then transported to the work site, where they are erected and connected to form the installation for the distillation of air.
The construction of the vaporizer-condensers is generally carried out by operations separate from those for the construction of the distillation and mixing columns, of the storage reservoirs for cryogenic liquid (of low capacity which can be up to about 10 m
3
) and more generally of the elements for confining the cryogenic fluid.
Because of this, the pre-assembly of the principal package is subject to delivery of the vaporizer-condenser, which gives rise to delays of prefabrication of the principal package and hence of the relatively long construction of the installation.
The invention has for its object to overcome this problem by providing an installation for the reliable and economical distillation of air that permits ensuring reduced construction delays.
To this end, the invention has for its object an installation for the distillation of air, comprising a medium pressure column, a low pressure column, a vaporizer-condenser for placing in heat exchange relation a calorigenic gas with the bottom liquid of the low pressure column and an element for confining cryogenic fluid, the low pressure column being beside the medium pressure column, characterized in that the base of the low pressure column is above the base of the medium pressure column and in that the low pressure column is disposed above this confinement element.
According to particular embodiments, the installation can comprise one or several of the following characteristics, alone or in any technically possible combination:
the vaporizer-condensor is disposed above the medium pressure column
the confinement element for cryogenic fluid comprises a mixing column;
the installation comprises means for sending air to the base of the mixing column, means for sending a fluid rich in oxygen toward the head of the mixing column and a conduit for the production of impure gaseous oxygen withdrawn from the head of the mixing column; and
the confinement element for cryogenic fluid comprises a storage reservoir of a cryogenic fluid, particularly liquid oxygen
the confinement element for the fluid is an argon column supplied from the low pressure column, a column operating at a pressure intermediate the low pressure and the medium pressure, or heat exchanger
the base of the low pressure column is located at the same level as the head of the medium pressure column or above this level.
the low pressure column and the confinement element are integral.
there is no distillation means above the medium pressure column.
The intermediate pressure column can be as described in EP-A-0538118 for example.
The heat exchanger may or may not be the vaporizer-condenser which permits heat exchange between the bottom liquid of the low pressure column and a calorigenic gas. For example, it may be a subcooler on the main heat exchanger in which feed air is cooled.
If the medium pressure column and the low pressure column are part of a conventional double column, the bottom liquid of the low pressure column is heated by the gas at the head of the medium pressure column and liquids enriched in oxygen and in nitrogen are sent from the medium pressure column to the low pressure column.
Preferably, the low pressure column and the confinement element for a cryogenic fluid are integral with each other.
The invention also has for its object a cold box adapted for the construction of an installation as described above, characterized in that it comprises the medium pressure column and the vaporizer-condenser or the low pressure column and the confinement element for cryogenic fluid, surrounded by a thermal insulation envelope.
According to another object of the invention, there is provided a process for erecting a separation apparatus comprising at least one medium pressure column, a low pressure column, if desired a confinement element for cryogenic fluid surmounted by the low pressure column, and a vaporizer-condenser to condense at least partially a calorigenic gas by heat exchange with a liquid from the low pressure column, in which the low pressure and medium pressure columns are mounted side by side, each column having its own cold box and once the medium pressure and low pressure columns are thus mounted, the vaporizer-condenser is mounted above the medium pressure column and the construction of the cold box of the medium pressure column is completed.
In particular, the vaporizer-condenser can permit condensing a gas from the medium pressure column by heat exchange with a liquid from the low pressure column.
REFERENCES:
patent: 5209070 (1993-05-01), Darredeau
patent: 5244489 (1993-09-01), Grenier
patent: 5412954 (1995-05-01), Grenier
patent: 5438835 (1995-08-01), Rathbone
patent: 5442925 (1995-08-01), Agrawal et al.
patent: 5461871 (1995-10-01), Bracque et al.
patent: 5485729 (1996-01-01), Higginbotham
patent: 5490391 (1996-02-01), Hogg et al.
patent: 5582031 (1996-12-01), Rathbone
patent: 5649433 (1997-07-01), Suzuki et al.
patent: 2 143 986 (1973-02-01), None
Capossela Ronald
L'Air Liquide, Societe Anonyme pour l'Etude et l'
Young & Thompson
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