Heat exchanger assembly and method for assembling same

A heat exchanger assembly comprising:

• a first heat exchanger being a higher-pressure heat exchanger and a second heat exchanger being a lower-pressure heat exchanger, the first heat exchanger and the second heat exchanger forming a main heat exchanger in a cryogenic air separation plant;
• a subcooler;
• a first heat exchanger cold box configured to accommodate the first heat exchanger and heat exchange fluid pipelines, the first heat exchanger cold box having a first opening being disposed in a side of the first heat exchanger cold box, and a first group of the heat exchange fluid pipelines of the first heat exchanger extending through the first opening;
• a second heat exchanger cold box configured to accommodate the second heat exchanger and heat exchange fluid pipelines, the second heat exchanger cold box having a second opening being disposed in a side of the second heat exchanger cold box, and a second group of the heat exchange fluid pipelines of the second heat exchanger extending through the second opening;
• and
• a subcooler cold box, configured to accommodate the subcooler and heat exchange fluid pipelines, the subcooler cold box having a third opening and a fourth opening being each disposed in a side of the subcooler cold box, and a third group of the heat exchange fluid pipelines of the subcooler and a fourth group of the heat exchange fluid pipelines of the subcooler extending through the third opening and the fourth opening respectively,
• wherein the first group of heat exchange fluid pipelines and the third group of heat exchange fluid pipelines are connected and encapsulated in a first thermally isolating casing, and the second group of heat exchange fluid pipelines and the fourth group of heat exchange fluid pipelines are connected and encapsulated in a second thermally isolating casing,
• wherein the first heat exchanger, the second heat exchanger, and the subcooler are all plate fin heat exchangers,
• wherein the subcooler is a heat exchanger that is separate from the main heat exchanger and formed by one or more heat exchanger units,
• wherein the subcooler is adapted to use one or more cold-state fluids from a lower-pressure column of the air separation plant to cool one or more fluids from a higher-pressure column of the air separation plant,
• wherein the subcooler is configured to send these cold-state fluids to the main heat exchanger thereby cooling a hot fluid, and
• wherein each one of the first and second thermally isolating casings are packed with thermally isolating material.