Device and method for liquefying a fluid such as hydrogen and/or helium
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Solution Overview
Problem
Existing methods for liquefying hydrogen and helium suffer from low isothermal efficiencies and high maintenance costs due to the use of cycle compressors, which also have limited volumetric capacity.
Innovation Solution
A device utilizing centrifugal compression with multiple stages and centripetal expansion, coupled to a helium-based refrigeration cycle, which integrates mechanical work recovery and countercurrent heat exchangers to enhance efficiency and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cycle compressors are used for liquefying hydrogen, then liquefaction can be achieved, but isothermal efficiency is low (60-65%) and maintenance costs are high
Solution Approach 1:
The patent replaces traditional cycle compressors with a centrifugal compression system driven by a turbine. The turbine expands high-pressure helium to drive the centrifugal compressor, substituting the mechanical compression system with a thermodynamic cycle that achieves higher isothermal efficiency (70-80%) while reducing maintenance requirements through fewer moving parts and lower operating stresses
Solution Approach 2:
The patent changes the compression mechanism from reciprocating/cycle compression to centrifugal compression, and changes the working fluid parameters by using helium as the cycle gas. This parameter change enables operation at higher speeds with smoother compression, improving isothermal efficiency and reducing mechanical wear and maintenance needs
2Productivity
If cycle compressors are used for liquefying hydrogen, then compression can be achieved, but volumetric capacity is limited
Solution Approach 1:
The patent replaces cycle compressors with a centrifugal compression system that operates at higher rotational speeds with continuous compression action. This substitution eliminates the intermittent compression cycles, increasing volumetric capacity and overall liquefaction output through continuous high-speed operation
Solution Approach 2:
The patent transitions from periodic/reciprocating compression action to continuous centrifugal compression. The centrifugal compressor operates continuously without the start-stop or back-and-forth motion of cycle compressors, achieving higher volumetric capacity and sustained liquefaction rates
3Loss of energy
If expansion work is not recovered, then system simplicity is maintained, but energy efficiency is reduced
Solution Approach 1:
The patent merges the expansion turbine and compression driver into a single integrated system where the turbine directly drives the centrifugal compressor through a common shaft. This combination recovers expansion work from high-pressure helium to power the compression process, improving energy efficiency while maintaining relatively simple system configuration through direct coupling
Solution Approach 2:
The patent implements a self-service energy recovery system where the expansion of helium gas automatically drives the compressor without requiring external power input for the compression stage. The system uses its own expansion energy to sustain the compression process, reducing overall energy loss and improving thermodynamic efficiency
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 device achieves isothermal efficiencies greater than 70% and active recovery of expansion work, reducing maintenance costs and improving overall efficiency in liquefying hydrogen and helium.
Implementation Method 1
the compression mechanism comprises at least four compression stages in series composed of an assembly of compressor(s) of the centrifugal type
Implementation Method 2
the expansion mechanism comprising at least three expansion stages in series composed of an assembly of turbines of the centripetal type
Implementation Method 3
an assembly of heat exchanger(s) in a heat exchange relationship with the circuit for fluid that is to be cooled
Implementation Method 4
a refrigerator that performs a refrigeration cycle on a cycle gas mainly comprising helium
Data Source
AI summary
Disclosed is a device for liquefying a fluid, comprising a fluid circuit to be cooled, the device comprising a heat exchanger assembly in heat exchange with the fluid circuit to be cooled, at least one first cooling system in heat exchange with at least a portion of the heat exchanger assembly, the first cooling system being a refrigerator having a cycle for refrigerating a cycle gas mainly comprising helium, said refrigerator comprising in series in a cycle circuit: a mechanism for compressing the cycle gas, at least one member for cooling the cycle gas, a mechanism for expanding the cycle gas, and at least one member for reheating the expanded cycle gas, wherein the compression mechanism includes at least four compression stages in series composed of a centrifugal compressor assembly, the compression stages being mounted on shafts that are rotationally driven by a motor assembly, the expansion mechanism comprising at least three expansion stages in series composed of a set of centripetal turbines, the at least one member for cooling the cycle gas being configured to cool the cycle gas at the outlet of at least one of the turbines, and wherein at least one of the turbines is coupled to the same shaft as at least one compression stage so as to feed the mechanical work produced during the expansion to the compression stage.