High-purity oxygen production system
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Solution Overview
Problem
Current methods for producing high-purity oxygen require costly liquefaction apparatus and result in energy inefficiency and pressure loss, particularly when liquid nitrogen is supplied remotely or in excess, affecting the rectification process in air separation apparatus.
Innovation Solution
A high-purity oxygen production system that integrates an air separation apparatus with a high-purity oxygen production apparatus, using nitrogen from the air separation apparatus to maintain cold heat balance, eliminating the need for a costly liquefaction apparatus and minimizing pressure loss by leveraging the medium-pressure column's pressure, with a liquid nitrogen buffer to stabilize supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If liquid nitrogen is supplied remotely by tanker lorry, then liquid nitrogen can be supplied to high-purity oxygen production apparatus, but transportation costs increase
Solution Approach 1:
The air separation apparatus produces its own liquid nitrogen internally through the medium-pressure column, eliminating the need for external supply by tanker lorry. The liquid nitrogen is generated on-site and directly supplied to the high-purity oxygen production apparatus, making the system self-sufficient and removing transportation costs.
2Ease of manufacture
If nitrogen is compressed and decompressed in liquefaction cycle, then liquid nitrogen can be produced, but energy consumption increases
Solution Approach 1:
The invention extracts liquid nitrogen directly from the medium-pressure column of the air separation apparatus without subjecting it to compression and decompression cycles. By taking out the liquid nitrogen at the point of production and utilizing its existing pressure, the system eliminates the energy-intensive liquefaction cycle while still providing liquid nitrogen to the high-purity oxygen production apparatus.
3Temperature
If liquid nitrogen is drawn in excess from medium-pressure column, then cold supply to high-purity oxygen production apparatus is ensured, but reflux liquid to low-pressure column is reduced, adversely affecting rectification
Solution Approach 1:
The system implements feedback control by monitoring the liquid nitrogen withdrawal amount from the medium-pressure column and adjusting it based on the actual cold heat balance requirements of the high-purity oxygen production apparatus. This ensures that liquid nitrogen is withdrawn only to the extent needed, preventing excessive withdrawal that would compromise the reflux liquid supply and rectification quality in the low-pressure column.
4Loss of energy
If liquid nitrogen pressure is matched to operating pressure, then pressure loss is minimized, but supply stability must be maintained
Solution Approach 1:
The system performs preliminary action by pre-cooling and pre-pressurizing the liquid nitrogen in the heat exchanger before it enters the high-purity oxygen production apparatus. By adjusting the liquid nitrogen pressure to match the operating pressure in advance through pressure regulation, the system minimizes pressure loss during supply while maintaining stable composition and flow characteristics.
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 reduces equipment costs, energy consumption, and pressure loss, while ensuring stable liquid nitrogen supply to the high-purity oxygen production process, enhancing thermal efficiency and maintaining rectification quality.
Implementation Method 1
a nitrogen condenser (3) for condensing a gas drawn from the medium-pressure column top (23)
Implementation Method 2
a heat exchanger for cooling and condensing an oxygen-containing gas drawn from the low-pressure column top (43) thereby producing liquid oxygen
Implementation Method 3
cooling and condensing an oxygen-containing gas
Implementation Method 4
an expansion turbine for expanding high-pressure nitrogen gas and driving a turbine
Implementation Method 5
expanding high-pressure nitrogen gas
Data Source
AI summary
Certain embodiments of the present invention lies in providing a high-purity oxygen production system which is capable of supplying liquid nitrogen in order to supply the cold required by a high-purity oxygen production apparatus, without the use of a costly conventional liquefaction apparatus.A high-purity oxygen production system in accordance with an embodiment can include: an air separation apparatus including a main heat exchanger, a medium-pressure column and a low-pressure column; and a high-purity oxygen production apparatus including a nitrogen compressor, a nitrogen heat exchanger and at least one (high-purity) oxygen rectification column, an oxygen-containing stream serving as a starting material for high-purity oxygen is supplied from the low-pressure column to the high-purity oxygen production apparatus, and liquid nitrogen obtained from the medium-pressure column is supplied to the high-purity oxygen production apparatus in order to replenish cold heat required for operation of the high-purity oxygen production apparatus.