Cryogenic Air Compression for Cost-Effective High-Pressure Oxygen
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Solution Overview
Problem
Current methods for producing oxygen under high pressure, such as 15 bars, are cost-prohibitive for small devices due to the need for expensive oxygen compressors and the technological infeasibility of combining low flow rates with high discharge pressures, which existing solutions like two-stage boosting and cryogenic cooling cannot efficiently address.
Innovation Solution
A process utilizing a single air compressor to achieve moderately high discharge pressure, where all air is brought to high pressure, purified, and divided for cryogenic compression, with energy from air expansion used to power turbines, reducing the need for expensive oxygen compressors and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If two boosters in series are used to compress air to high pressure, then oxygen can be produced under pressure, but the process complexity increases due to the need for refrigeration units and multiple compression stages
Solution Approach 1:
The patent combines the compression and cooling functions into a single integrated cryogenic compressor unit. The compression stages and intercooling stages are merged into one device, eliminating the need for separate boosters and refrigeration units. This reduces the number of components while maintaining the ability to produce oxygen under high pressure.
Solution Approach 2:
The cryogenic compressor is designed as a multi-functional device that performs both compression and cooling operations within a single unit. The same device handles multiple stages of compression and intercooling, making it a universal solution that replaces multiple specialized components.
2Ease of manufacture
If a single air compressor is used at moderately high discharge pressure, then installation costs are reduced, but the discharge pressure is insufficient for direct oxygen vaporization at desired pressure levels
Solution Approach 1:
The patent changes the temperature parameter of the air stream by implementing cryogenic cooling during compression. This temperature reduction allows the gas to reach higher pressure levels that would otherwise be unattainable with conventional compression alone, enabling direct oxygen vaporization at the desired pressure without additional boosting.
Solution Approach 2:
The system dynamically adjusts the compression and cooling processes to achieve the target pressure. The cryogenic compressor dynamically manages the intercooling stages to optimize the pressure-temperature relationship, allowing flexible operation at different discharge pressures while maintaining cost-effectiveness.
3Stress or pressure
If oxygen compressors are used for small devices, then high-pressure oxygen can be produced, but the equipment cost becomes prohibitively expensive
Solution Approach 1:
The cryogenic compressor serves itself by using the heat extracted during compression to pre-cool the incoming air. This self-cooling mechanism eliminates the need for external refrigeration systems and expensive oxygen compressors, making high-pressure oxygen production economically viable for small devices.
Solution Approach 2:
The patent introduces cryogenic temperature as an intermediary condition that enables cost-effective high-pressure oxygen production. By cooling the air to very low temperatures during compression, the system achieves high discharge pressures using a single air compressor instead of expensive oxygen compressors.
4Temperature
If air is cooled to intermediate temperatures in an exchange line, then cryogenic compression can be effective, but the temperature management complexity increases
Solution Approach 1:
The patent applies preliminary cooling to the compressed air in intercooling stages before each compression stage. This pre-cooling action prepares the gas for the next compression stage, improving compression efficiency and enabling the cryogenic conditions necessary for high-pressure oxygen production without requiring complex real-time temperature management.
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 significantly reduces installation costs for small oxygen production devices by eliminating the need for expensive oxygen compressors and optimizing energy use through cryogenic compression and turbine-driven expansion, making high-pressure oxygen production more economically viable.
Implementation Method 1
All the air is brought to high pressure and purified, then divided into at least two parts. Only a fraction of the air undergoes a succession of cryogenic compressions... the air is cooled to intermediate temperatures in an exchange line
Implementation Method 2
the rest of the air is expanded in at least one turbine to the pressure of the medium pressure column. At least part of the work released by the expansion of the air is used for the cryogenic compression
Implementation Method 3
Only a fraction of the air, the fraction which liquefies later at the cold end of the main exchange line, undergoes a succession of cryogenic compressions
Data Source
Figure 1
AI summary
The invention relates to a method for separating air by means of cryogenic distillation in a system of columns, in which two single-stage air superchargers (15, 25) are connected in series and coupled to two turbines (17, 27) which expand the air that was not supercharged. The superchargers supercharge the cooled high-pressure air in an exchange line in which the oxygen from the system of columns is vaporised.