Air Separation Cold Box Layout With Suspended Subcooling Exchanger
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Solution Overview
Problem
Existing low-temperature air separation devices face challenges in optimizing the arrangement of plant components, particularly in reducing space requirements and piping complexity, while maintaining efficient fluid communication between the main heat exchanger and subcooling-counterflow heat exchanger.
Innovation Solution
The subcooling-counterflow heat exchanger is arranged below the main heat exchanger with fluid communication via pipelines, allowing for suspension directly from the main heat exchanger, thereby reducing the width of the cold box and eliminating the need for complex expansion loops and additional supports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the subcooling-counterflow heat exchanger is arranged separately from the main heat exchanger, then functional independence and thermal efficiency are improved, but device complexity and space requirements increase
Solution Approach 1:
The subcooling-counterflow heat exchanger is nested within the cold box that also contains the main heat exchanger, with the subcooling heat exchanger positioned below the main heat exchanger. This nesting arrangement allows functional independence while sharing the same insulated enclosure, reducing overall space requirements and simplifying the structural framework.
Solution Approach 2:
The subcooling-counterflow heat exchanger is arranged vertically below the main heat exchanger rather than horizontally adjacent to it. This vertical arrangement in the height dimension reduces the horizontal footprint and cold box width, while pipelines connect the two heat exchangers to maintain fluid communication.
2Ease of manufacture
If the cold box width is reduced for easier transportation, then ease of manufacture and transport are improved, but piping complexity and assembly difficulty increase
Solution Approach 1:
The subcooling heat exchanger is positioned vertically below the main heat exchanger, utilizing the height dimension rather than horizontal space. This reduces the cold box width for easier transportation while the vertical arrangement allows for straightforward pipeline connections between the two heat exchangers.
Solution Approach 2:
The heat exchangers are arranged at different vertical levels within the cold box, creating a gravity-assisted flow path. Liquid can flow downward from the main heat exchanger to the subcooling heat exchanger, and vapor can rise back, reducing the need for complex pumping and expansion loop systems.
3Device complexity
If the subcooling heat exchanger is suspended from the main heat exchanger, then structural complexity and support requirements are reduced, but mechanical stability and vibration resistance worsen
Solution Approach 1:
The subcooling heat exchanger is suspended from the main heat exchanger using its own piping connections, eliminating the need for separate support structures. The piping system that provides fluid communication also serves the dual function of mechanical support, simplifying the overall structure.
Solution Approach 2:
The support function is merged with the piping system. The same pipes that connect the subcooling heat exchanger to the main heat exchanger for fluid flow also provide the mechanical suspension, combining two functions into a single structural element.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration simplifies piping, reduces the overall width of the cold box, and allows for easier transportation and assembly, while maintaining efficient fluid flow and thermal insulation, enhancing the operational efficiency of the air separation process.
Implementation Method 1
A 'main heat exchanger' serves for cooling feed air by indirect heat exchange with backflows from the distillation column system for nitrogen-oxygen separation
Implementation Method 2
A 'subcooling counterflow heat exchanger' is a unit separate from the main heat exchanger and serves for subcooling or warming one or more liquids from one of the columns of the distillation column system for nitrogen-oxygen separation, or else from a mixed column in counterflow to one or more cold gaseous backflows
Implementation Method 3
When liquid oxygen from a low-pressure column, before it is fed into a mixed column, is conducted through the subcooling counterflow heat exchanger, this is reciprocally warmed, in order to come as close as possible to the boiling point at the—generally higher—pressure of the mixed column
Implementation Method 4
a distillation column system for nitrogen-oxygen separation having at least one high-pressure column
Data Source
AI summary
The invention relates to an apparatus for the low-temperature separation of air and comprises a main heat exchanger (6) having at least two heat-exchanger blocks, a distillation column system for nitrogen-oxygen separation (5) having at least one high-pressure column, a subcooling-counterflow heat exchanger (2), means for introducing feed air via the main heat exchanger (6) into the high-pressure column, means for introducing a liquid stream from the distillation column system into the subcooling-counterflow heat exchanger (2), and means for introducing a gas stream (16) from the distillation column system into the subcooling-counterflow heat exchanger (2). The main heat exchanger (6) and the subcooling-counterflow heat exchanger (2) are arranged in a first cold box (12), and the subcooling-counterflow heat exchanger (2) is suspended from the main heat exchanger (6).