Air separation unit
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Solution Overview
Problem
Conventional air separation methods face challenges in maintaining high recovery rates of argon and high-purity oxygen without complicating apparatus configurations or increasing the number of components, particularly due to the use of medium-pressure nitrogen gas as a reboiling source, which reduces argon recovery rates.
Innovation Solution
An air separation unit utilizing a main heat exchanger, multiple rectification columns, and a high-purity oxygen reboiler, where feed air is used as a heat source in the reboiler, eliminating the need for a nitrogen compressor and additional condensers, and optimizing the supply of feed air to maintain argon and oxygen production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If medium-pressure nitrogen gas is used as a reboiling source for high-purity oxygen, then high-purity oxygen can be produced, but argon recovery rate decreases significantly
Solution Approach 1:
The invention extracts the problematic medium-pressure nitrogen gas from the reboiling process and replaces it with feed air. This removes the harmful effect of nitrogen gas reduction on argon recovery while maintaining the oxygen purification function through the same rectification column configuration.
Solution Approach 2:
The invention changes the parameter of the reboiling source from medium-pressure nitrogen gas to feed air. This parameter change resolves the contradiction by providing sufficient vapor stream for argon recovery in the low-pressure column while still enabling high-purity oxygen production through the rectification process.
2Loss of energy
If recycled nitrogen is used as a reboiling source, then energy efficiency improves, but apparatus complexity increases due to additional components
Solution Approach 1:
The invention makes the feed air serve multiple functions: it acts as the reboiling source for high-purity oxygen production and simultaneously provides vapor stream for argon recovery in the low-pressure column. This multi-functionality eliminates the need for separate recycled nitrogen systems while maintaining energy efficiency.
Solution Approach 2:
The feed air system serves itself by directly providing the reboiling function without requiring external recycled nitrogen loops, compressors, or additional condensers. The same feed air that drives oxygen rectification also supports argon recovery, creating a self-sufficient system.
3Manufacturing precision
If medium-pressure nitrogen gas is supplied to the low-pressure column bottom, then oxygen rectification is maintained, but argon recovery is reduced due to vapor stream reduction
Solution Approach 1:
The invention uses feed air as an intermediary substance that mediates between oxygen rectification requirements and argon recovery needs. The feed air provides the necessary vapor stream to the low-pressure column bottom, simultaneously supporting both oxygen purification and argon recovery without the trade-off created by medium-pressure nitrogen gas.
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 allows for efficient production of high-purity oxygen and argon with reduced apparatus complexity, maintaining argon recovery rates while avoiding reductions in argon production.
Implementation Method 1
a high-purity oxygen reboiler (9), wherein a portion of the feed air is used as a heat source in the high-purity oxygen reboiler (9)
Implementation Method 2
a main heat exchanger (1) for subjecting feed air to heat exchange
Implementation Method 3
a nitrogen condenser (3) which is disposed above the first column top portion (23) and condenses the first vaporized gas in the first column top portion (23)
Implementation Method 4
a crude argon condenser (6) which is disposed above the third column top portion (53) and condenses the argon in the third column top portion (53)
Implementation Method 5
a first rectification column (medium-pressure rectification column) (2)... a second rectification column (low-pressure rectification column) (4)... a third rectification column (crude argon column) (5)... a high-purity oxygen rectification column (8)
Data Source
AI summary
An air separation unit may include: a main heat exchanger 1, a first rectification column 2, a nitrogen condenser 3, a second rectification column 4, a third rectification column 5, a crude argon condenser 6, a high-purity oxygen rectification column 8, and a high-purity oxygen reboiler 9. The air separation unit uses a portion of the feed air that has passed through the main heat exchanger 1 as a heat source in the high-purity oxygen reboiler 9.