Cryogenic Air Separation Exchanger Layout for Reduced Piping
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Solution Overview
Problem
Existing air separation devices at low temperatures face challenges in optimizing the arrangement of system parts, particularly in minimizing piping effort and transport dimensions while maintaining efficient thermal insulation and process flow.
Innovation Solution
The subcooling countercurrent is arranged below the main heat exchanger, with direct fluidic connection, avoiding complex support structures and allowing for easier piping and reduced cold box width, enabling more efficient use of space and transportability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the subcooling counterflow unit is arranged beside the main heat exchanger in conventional configurations, then the system maintains functional separation, but the cold box width increases and piping complexity increases
Solution Approach 1:
The subcooling counterflow unit is moved from a horizontal arrangement (beside the main heat exchanger) to a vertical arrangement (directly below it), utilizing the vertical dimension to reduce the horizontal footprint and cold box width while simplifying piping connections through direct fluidic integration
2Use of energy by moving object
If the main heat exchanger volume is increased to improve thermal exchange efficiency, then the thermal exchange performance improves, but the transport dimensions exceed standard limits
Solution Approach 1:
The heat exchanger system is segmented into two functional units: the main heat exchanger and the subcooling counterflow unit. This segmentation allows the main heat exchanger to be optimized for thermal efficiency while the compact subcooling unit fits within transportable dimensions, and the vertical arrangement maximizes space utilization within transport constraints
3Reliability
If complex support structures are used to hold the subcooling counterflow unit, then structural stability is ensured, but manufacturing complexity and installation difficulty increase
Solution Approach 1:
The subcooling counterflow unit utilizes its own weight and the gravitational force acting on it to achieve self-suspension from the main heat exchanger, eliminating the need for additional complex support structures and simplifying both manufacturing and installation while maintaining structural stability
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 arrangement reduces piping complexity, allows for a larger main heat exchanger volume within transport limits, and facilitates prefabrication of medium-sized systems, enhancing operational efficiency and transportability of air separation plants.
Implementation Method 1
A 'main heat exchanger' serves to cool the process air in an indirect heat exchange with return flows from the distillation column system for nitrogen-oxygen separation
Implementation Method 2
A 'subcooling counterflow unit' is a separate unit from the main heat exchanger and serves to subcool or warm one or more liquids from one of the columns of the distillation column system for nitrogen-oxygen separation, or from a mixing column, in counterflow to one or more cold gaseous return streams
Implementation Method 3
Methods and devices for the low-temperature separation of air are known, for example, from Hausen/Linde, Low-Temperature Technology, 2nd edition 1985, Chapter 4 (pages 281 to 337)
Implementation Method 4
The insulating effect can be achieved by appropriately designing the outer walls and/or by filling the space between the system components and the outer walls with an insulating material
Data Source
Figure 1~2
AI summary
The device has a main heat exchanger (6) comprising two heat exchanger-blocks, and a distillation column-system (5) for separating nitrogen and oxygen. A supercooling-heat exchanger (2) is separated from the main heat exchanger. A conduit (16) conducts gas flow from the column-system to the supercooling-heat exchanger, where the main and supercooling-heat exchangers are arranged in a coldbox. An upper end of the supercooling-heat exchanger is arranged below a lower end of the main heat exchanger. The supercooling-heat exchanger is suspended at the main heat exchanger over pipelines (17-19).