Active magnetic regenerative liquefier using process gas pre-cooling from bypass flow of heat transfer fluid
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Solution Overview
Problem
Current hydrogen liquefaction technologies are inefficient and costly due to low figure of merit (FOM), leading to high operating costs and limited deployment of hydrogen fuel infrastructure, which hinders the adoption of hydrogen as a fuel source.
Innovation Solution
The use of active magnetic regenerative refrigerators (AMRRs) with a bypass flow heat exchanger design that operates below the Curie temperature of magnetic refrigerants, optimizing heat transfer and reducing the number of stages required for liquefaction, thereby increasing the FOM and reducing the mass of magnetic refrigerants needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional liquid nitrogen pre-cooled Claude-cycle plants are used for hydrogen liquefaction, then liquefaction can be achieved, but the figure of merit is limited to approximately 0.35, resulting in high operating costs
Solution Approach 1:
The patent changes the fundamental operating parameters by using active magnetic regenerative refrigeration instead of conventional Claude-cycle with liquid nitrogen pre-cooling. The magnetic refrigeration system operates with heat transfer fluids flowing through magnetized and demagnetized beds, achieving different temperature profiles and heat transfer characteristics that improve the figure of merit beyond the conventional 0.35 limit
Solution Approach 2:
The patent introduces a bypass flow heat exchanger as an intermediary component that pre-cools the process gas using the cold heat transfer fluid from the magnetic refrigeration system. This intermediary heat exchanger optimizes heat transfer efficiency and enables the system to achieve higher FOM by effectively utilizing the cold capacity before the main liquefaction process
2Device complexity
If the number of stages and mass of magnetic refrigerants are reduced, then device complexity and cost decrease, but maintaining high figure of merit becomes more difficult
Solution Approach 1:
The patent applies partial action by using a bypass flow that diverts only a portion of the heat transfer fluid through the magnetic refrigeration beds while another portion flows through the bypass heat exchanger. This partial flow configuration allows the system to achieve effective pre-cooling with reduced magnetic refrigerant mass and fewer stages, while maintaining high FOM through optimized heat transfer
Solution Approach 2:
The patent segments the heat transfer fluid flow into multiple paths: one path through the magnetized/demagnetized beds for active cooling and another path through the bypass heat exchanger for pre-cooling the process gas. This segmentation allows independent optimization of each flow path, enabling reduced complexity while maintaining high 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
This design significantly enhances the efficiency of hydrogen liquefaction, achieving a higher figure of merit (FOM) and reducing the number of stages and magnetic refrigerant mass, resulting in a more cost-effective and scalable hydrogen liquefaction process.
Implementation Method 1
an active magnetic regenerative refrigerator apparatus that comprises (i) a high magnetic field section in which the heat transfer fluid flows from a cold side to a hot side through at least one magnetized bed of at least one magnetic refrigerant
Implementation Method 2
continuously diverting a bypass portion of the heat transfer fluid from the cold side of the low magnetic or demagnetized field section into a bypass flow heat exchanger
Data Source
AI summary
A process for liquefying a process gas that includes:introducing a heat transfer fluid into an active magnetic regenerative refrigerator apparatus that includes a low magnetic or demagnetized field section;continuously diverting a bypass portion of the heat transfer fluid from a cold side of the low magnetic or demagnetized field section into a bypass flow heat exchanger at a first cold inlet temperature; andcontinuously introducing the process gas into the bypass flow heat exchanger at a first hot inlet temperature and discharging the process gas or liquid from the bypass flow heat exchanger at a first cold exit temperature;wherein the temperature difference between bypass heat transfer first cold inlet temperature and the process gas first cold exit temperature is 1 to 5 K.