Device for the cryogenic separation of air

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Solution Overview

Problem

Existing air separation systems for nitrogen-oxygen separation lack an optimized spatial arrangement of the mixing column in relation to other components, leading to inefficient use of space and potential suboptimal thermal insulation.

Innovation Solution

The mixing column, high-pressure column, low-pressure column, and subcooling countercurrent are housed within a common cold box, with the mixing column positioned above or laterally offset to the subcooling countercurrent, allowing for a compact design and improved thermal insulation by using the otherwise unused space above the subcooling countercurrent flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of stationary object

If the mixing column is arranged on the floor or beside other columns as in prior art, then the spatial arrangement is conventional and easy to implement, but the space utilization is inefficient and the thermal insulation is suboptimal

Engineering Contradiction:
Improvespace utilizationVSAvoidarrangement complexity
Core Design Contradiction:
Volume of stationary objectVSDevice complexity

Solution Approach 1:

The patent transitions from conventional horizontal/ground-level arrangement to a vertical three-dimensional arrangement, placing the mixing column above the subcooling countercurrent flow unit. This spatial reconfiguration in the vertical dimension achieves compactness and efficient space utilization while maintaining operational simplicity through standardized support structures.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of stationary object

If the mixing column is positioned to utilize unused space above the subcooling countercurrent flow, then the device becomes more compact and space-efficient, but the thermal insulation requirements become more stringent

Engineering Contradiction:
Improvedevice compactnessVSAvoidthermal insulation
Core Design Contradiction:
Volume of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent merges the mixing column and subcooling countercurrent flow unit into a single integrated cold box structure. This combination allows the external insulation of the cold box to simultaneously protect both components, eliminating the need for separate insulation systems and reducing overall thermal losses while achieving compact design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The mixing column is positioned within the vertical envelope defined by the cold box that also contains the subcooling countercurrent flow unit. This nested arrangement optimizes the use of available thermal insulation volume while maintaining efficient thermal boundaries for both components.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Loss of energy

If all cold parts including the main heat exchanger are enclosed in a common cold box, then the thermal insulation is optimized and space is efficiently used, but the device complexity increases

Engineering Contradiction:
Improvethermal efficiencyVSAvoidstructural complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent combines multiple cold components (double column, mixing column, subcooling countercurrent flow unit, and main heat exchanger) into a single common cold box. This merger creates a unified thermal envelope that minimizes external heat infiltration and simplifies the insulation system, while the modular internal arrangement maintains operational independence of each component.

Inventive Principle:
Principle #5Merging (Combining)

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 minimizes the proportion of pre-liquefied air and enhances thermal efficiency by optimizing the spatial orientation of components, resulting in a more compact and thermally efficient nitrogen-oxygen separation system.

Implementation Method 1

a main heat exchanger with a process air inlet and with product gas outlets for product nitrogen and product oxygen

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a distillation column system for nitrogen-oxygen separation, comprising a high-pressure column and a low-pressure column

Methodology Applied
Scientific EffectDistillation: Distillation

Implementation Method 3

The counter-current subcooling system is used to supercool or warm one or more liquids from one of the columns of the nitrogen-oxygen separation distillation system or the mixing column in counter-current flow to one or more cold gaseous streams

Methodology Applied
Scientific EffectCounter-current heat exchange: Heat Exchanger

Implementation Method 4

a common cold box with a mixing column, subcooling counterflow unit and double column, which in particular encloses all cold parts of the device

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP2553369B1Device for the cryogenic separation of air
Publication Date: 2019.09.18 LINDE AG
  • EP2553369B1 patent drawingFigure 1~2

AI summary

The device serves for the cryogenic separation of air. It has the following features: a main heat exchanger and a supercooling countercurrent heat exchanger (2); a distillation column system for nitrogen-oxygen separation (5), which comprises a high-pressure column and a low-pressure column; a mixing column (1); means for introducing charge air via the main heat exchanger into the high-pressure column and into the mixing column; a liquid-oxygen line for introducing liquid oxygen from the low-pressure column into the upper region of the mixing column; an oxygen product line for extracting oxygen gas from the upper region of the mixing column through the main heat exchanger. The mixing column (1) and at least one of the two heat exchangers mentioned (2, 6) are arranged in a common cold box (3).