Compressed Air Cooling Using Cold Box Gas in Cryogenic Separation

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Solution Overview

Problem

Current air compression and cooling systems for cryogenic separation devices are large and inefficient, particularly in summer, due to the need for significant water handling and the use of refrigeration units and water/nitrogen towers, which complicates integration into compact shipping containers.

Innovation Solution

The method involves using gaseous products from a cold box to cool humid air in an exchanger, where condensed water from the air and compression is injected back into the gases, eliminating the need for a dryer or refrigeration unit and integrating the exchanger into the main cooling line, allowing for isothermal compression and recovery of water to humidify nitrogen gas beyond saturation point.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional cooling systems (refrigeration units, water/nitrogen towers) are used to cool compressed air, then the air can be cooled effectively, but the equipment size becomes large and the system complexity increases

Engineering Contradiction:
Improveair cooling efficiencyVSAvoidcooling system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges the cooling function with the existing cold box by integrating the air cooling process into the cryogenic distillation system. The compressed air is cooled using the cold box's cold gases (nitrogen and oxygen) instead of requiring separate refrigeration units or water/nitrogen towers, thereby reducing equipment size and system complexity while maintaining effective cooling

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cold box serves multiple functions: it performs cryogenic distillation to separate nitrogen and oxygen, and simultaneously provides cold gases for cooling the compressed air. This multi-functionality eliminates the need for dedicated cooling equipment, reducing both size and complexity of the overall system

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Temperature

If conventional cooling systems with significant water handling are used, then air cooling is achieved, but the equipment size increases making shipping container integration difficult

Engineering Contradiction:
Improveair cooling capabilityVSAvoidequipment size
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The cooling system is merged with the cold box structure, using the same vessel and cold gases for both cryogenic distillation and air cooling. This integration eliminates the need for separate large-volume cooling equipment, reducing overall equipment size to enable shipping container integration

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system uses its own cold gases (nitrogen and oxygen from the cryogenic distillation process) to cool the compressed air, rather than requiring external water cooling systems. This self-service approach eliminates water handling equipment and reduces the volume required for cooling systems

Inventive Principle:
Principle #25Self-service

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 approach simplifies the cooling system, reduces equipment size, and avoids costly direct heat exchange, enabling efficient air cooling and purification while maintaining compactness, suitable for shipping container integration.

Implementation Method 1

Method of compressing and cooling air by indirect heat exchange

Methodology Applied
Scientific EffectIndirect heat exchange: Heat Exchanger

Implementation Method 2

the condensed water from the air and compression is injected back into the gases

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

i) compressing air

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 4

the quantity of water mixed with the gaseous nitrogen is such that at the entry point of the water mixed with the gaseous nitrogen of the first exchanger and/or at the intermediate point of the first exchanger where the mixing takes place, the mixing of nitrogen gas and water is beyond the water saturation point

Methodology Applied
Scientific EffectHumidification:

Data Source

PatentEP2504647B1Method and apparatus for compressing and cooling air
Publication Date: 2019.02.20 LAIR LIQUIDE SA POUR LETUDE & LEXPLOITATION DES PROCEDES GEORGES CLAUDE
  • EP2504647B1 patent drawingFigure 1

AI summary

The invention relates to a method for compressing and cooling air upstream from a facility for cryogenic separation of air, with no means for exchange by indirect heat, in which humid air is compressed in a compressor (3), the air compressed in the compressor is cooled in a first exchanger having indirect heat exchange (13), water (11, 19) is recovered from the air upstream and/or downstream from cooling in the first exchanger, the air cooled in the first exchanger is sent to a purification unit (45) in order to produce air purified of carbon dioxide and/or water, the purified air is sent to the cryogenic separation facility, at least one gas is recovered from the cryogenic separation facility, the recovered water is mixed with the gas from the facility, the mixture produced being at a temperature higher than the temperature of solidification of the water in the mixture and the water mixed with the gas is reheated in the first exchanger.