Cryocooler Gas Liquefaction with Elevated Pressure Control
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Solution Overview
Problem
Current small-scale liquefaction plants for producing less than 20 liters of liquefied cryogen per day are inefficient compared to larger scale plants, and medium and large scale plants are complex and require extensive maintenance, with small-scale liquefiers achieving performance rates far below their needs.
Innovation Solution
A gas liquefaction system utilizing a cryocooler that operates at elevated pressures to enhance cooling power, with precise pressure control within the liquefaction region to improve liquefaction rates and efficiency, employing a unitary pressure control module or series of pressure control components to regulate gas flow and maintain elevated internal pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If small-scale liquefaction plants operate at standard conditions, then they are simpler in design, but their liquefaction efficiency is less than 2 liters/day/kW which is substantially inefficient
Solution Approach 1:
The patent applies parameter changes by operating the liquefaction system at elevated pressures (above atmospheric pressure) rather than at standard conditions. This pressure parameter change enables the system to achieve liquefaction efficiencies exceeding 7 liters/day/kW, representing a more than threefold improvement over conventional small-scale plants. The elevated pressure condition fundamentally alters the thermodynamic properties of the gas, enabling more efficient heat transfer and condensation processes.
Solution Approach 2:
The system implements dynamic pressure control through a pressure control mechanism that actively maintains elevated pressure conditions within the liquefaction chamber. This dynamic control allows the system to adapt to varying operational conditions while sustaining the optimized pressure regime, thereby maintaining high liquefaction efficiency. The dynamic adjustment capability enables the system to respond to changes in gas flow rate, temperature, and demand conditions.
2Productivity
If medium and large scale liquefaction plants are used, then high liquefaction rates are achieved, but they involve substantial complexity and require extensive maintenance
Solution Approach 1:
The patent achieves high liquefaction rates in a compact system by fundamentally changing the operating pressure parameter. By operating at elevated pressures, the system attains liquefaction rates comparable to medium and large-scale plants while maintaining a small-scale footprint. This parameter change enables efficient heat transfer coefficients and condensation rates that would otherwise require large-scale infrastructure.
Solution Approach 2:
The dynamic pressure control mechanism enables the small-scale system to achieve and maintain high liquefaction rates that typically require large-scale infrastructure. The active pressure regulation allows the compact system to operate at optimized conditions, dynamically adjusting to maintain high efficiency and throughput comparable to much larger facilities.
3Ease of operation
If small-scale liquefiers operate at atmospheric pressure, then the system is easier to operate, but their performance is far below the needs of users requiring more than 2 liters/day/kW
Solution Approach 1:
The system maintains ease of operation by automating the pressure control process through a dedicated pressure control mechanism. While the system operates at elevated pressures to achieve high performance, the pressure management is handled automatically, shielding the user from the complexity of high-pressure operations. The system provides user-friendly operation despite the advanced thermodynamic conditions internally.
Solution Approach 2:
The pressure control mechanism operates autonomously to maintain optimized pressure conditions, enabling the system to self-regulate and maintain high performance without requiring user intervention. The system automatically adjusts pressure parameters to sustain liquefaction efficiency above 7 liters/day/kW, making the advanced functionality transparent to the user and maintaining operational simplicity.
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
The system achieves a significant improvement in liquefaction efficiency, exceeding 7 liters/day/kW, by leveraging increased cooling power at higher liquefaction temperatures and precise pressure control, outperforming existing small-scale liquefiers.
Implementation Method 1
the gas to be liquefied does not undergo the complex thermodynamic cycles, but rather cools simply by thermal exchange with either the cold stages of the cryocooler, or with heat exchangers attached to the cold stages of the cryocooler
Implementation Method 2
a means for controlling pressure within a liquefaction region of the system such that an elevated pressure provides operation at increased liquefaction temperature
Implementation Method 3
adapted to utilize the thermodynamic properties of gaseous elements to extract increased cooling power from the cryocooler by operating at elevated pressures, and hence elevated liquefaction temperatures
Implementation Method 4
The system according to embodiments of the invention is adapted to maintain precise control over the vapor pressure inside the container, and thus is adapted to maintain precise control of the temperature and hence the power of the cryocooler where condensation is produced
Data Source
AI summary
A system and a method for liquefaction of gases which are utilized in their liquid state as refrigerants in applications that require low temperatures, throughout various pressure ranges, from slightly above atmospheric pressures to pressures near the critical point. The system and method are based on closed-cycle cryocoolers and utilize the thermodynamic properties of the gas to achieve optimal liquefaction rates.