Cryogenic Air Separation Column Layout for Compact Cold Boxes
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Solution Overview
Problem
Existing air distillation technologies face challenges in optimizing the volume usage of cold boxes and ensuring efficient liquid loading and two-phase air supply in air separation apparatuses, particularly with the placement and configuration of subcoolers and columns.
Innovation Solution
A double air separation column apparatus with a medium pressure column and a low pressure column thermally connected by a reboiler-condenser, where the subcooler is strategically placed to balance column heights and optimize the cold box volume, allowing for a compact design with corrugated-crossed structured packing and a parallel section with a height of less than 35 meters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the subcooler is placed below the low pressure column with traditional configurations, then the column heights can be optimized, but the cold box volume is not efficiently utilized and the overall height exceeds 35 meters
Solution Approach 1:
The subcooler is repositioned from a vertical arrangement to a horizontal arrangement at ground level, changing the spatial dimension of placement. This allows the cold box to be shortened in height while maintaining adequate cooling function, achieving a height under 35 meters while efficiently utilizing the cold box volume.
2Productivity
If the medium pressure column is elevated, then the low pressure column can be positioned for optimal performance, but the two-phase air supply and liquid loading efficiency are compromised
Solution Approach 1:
The medium pressure column is placed at ground level, creating an equipotential position that facilitates natural two-phase air supply and optimal liquid loading. This ground-level placement eliminates the need for complex pumping systems and ensures efficient operation of the distillation process.
3Length of stationary object
If the cold box height is reduced to under 35 meters, then the apparatus becomes more compact, but the configuration of subcooler and columns becomes more complex
Solution Approach 1:
The apparatus is segmented into distinct functional modules: the medium pressure column, low pressure column, subcooler, and reboiler-condenser are arranged as separate but thermally connected units. This modular segmentation allows each component to be optimized independently while maintaining an overall compact configuration under 35 meters in height.
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 enhances the efficiency of air separation by ensuring good liquid loading and two-phase air supply, optimizing the cold box volume, and enabling a compact design while maintaining effective operation.
Implementation Method 1
a double column thermally connected together by a reboiler-condenser
Implementation Method 2
Nitrogen from the head of the column is sent to the reboiler 5 where it condenses
Implementation Method 3
In the subcooler, rich liquid from the vessel of the medium pressure column is cooled before being sent to the second elongated element
Implementation Method 4
corrugated-crossed structured packings
Implementation Method 5
corrugated-crossed structured packings
Implementation Method 6
A bottom liquid 13 of column 3 is sent to the top of the auxiliary column 2 after having been pressurized in a pump p
Data Source
Figure 1
AI summary
The invention relates to an air separation apparatus that comprises a first member (A) having an elongated shape and including the medium-pressure column (1) of a dual column, on top of which are provided a reboiler-condenser (5) and an auxiliary column (2) containing at least one theoretical plate defining the lower portion of the low-pressure column, a second member (B) having an elongated shape and defining the rest of the low-pressure column, means (11) for supplying air from the main exchange line to the medium-pressure column and a subcooler (6) provided under the first or second member having an elongated shape, means for supplying a tank liquid from the medium-pressure column to the subcooler and then to the second member having an elongated shape and/or a means for supplying a liquid from the head of the medium-pressure column to the subcooler and then to the second member having an elongated shape, and means for supplying a gas from the head of the second member having an elongated shape to the subcooler.