Process and apparatus for establishing vacuum insulation under cryogenic condition
AssigneeL'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
InventorsAlain Briglia, Vincent Gueret, Ren Chen
Life of this patent
Estimating the term…
Abstract
A process for establishing vacuum insulation under cryogenic condition and an apparatus compatible with such process are described. When an insulation enclosure filled with high purity CO2 is evacuated to around 100 absolute Pa at ambient temperature, hard vacuum of below 1 absolute Pa may be automatically obtained within the insulation enclosure when temperature drops to around or below −170° C. This process can be employed to provide vacuum insulation for cold box housing air separation units operated under cryogenic condition.
Claims34
A process for establishing an insulation enclosure, the process comprising the steps of:
- a) providing the insulation enclosure having a casing encompassing a cryogenic equipment, wherein the cryogenic equipment comprises a rectification column used in cryogenic air separation to produce oxygen, nitrogen, argon or other pure components of air;
- b) providing a filling gas of a desired purity to the insulation enclosure;
- c) performing a first purging cycle to the insulation enclosure by evacuating the insulation enclosure from a first starting pressure to a first intermediate vacuum, followed by re-pressuring the insulation enclosure with the filling gas to a second starting pressure;
- d) creating and maintaining a primary vacuum in the insulation enclosure filled primarily with the filling gas;
- and
- e) operating the cryogenic equipment to cool the insulation enclosure and the filling gas to a temperature sufficiently low to solidify the filling gas, thus creating a final vacuum in the insulation enclosure;
- wherein starting from the primary vacuum, the filling gas undergoes transformation from gas phase to solid phase directly during cooling caused by the operation of the cryogenic equipment,
- wherein at least a portion of the filling gas comes in direct contact with the rectification column during step e),
- wherein the process further comprises an absence of adding an insulating material to the inside of the insulation enclosure.
An insulation enclosure for a cryogenic equipment, comprising:
- a) a casing encompassing the cryogenic equipment and the insulation enclosure being filled mostly with a filling gas of a desired purity;
- b) said insulation enclosure being evacuated to and maintained at a primary vacuum;
- c) a final vacuum being achieved in the insulation enclosure after the filling gas is solidified during the cooling caused by the operation of the cryogenic equipment;
- and
- wherein starting from the primary vacuum, the filling gas undergoes transformation from gas phase to solid phase directly during the cooling of the insulation enclosure caused by the operation of the cryogenic equipment wherein the insulation enclosure comprises an absence of adding an insulating material to the inside of the insulation enclosure.
Dependencies are inferred from the claim text.