Hydrogen Liquefaction Cascade Cooling With Two Closed Refrigerant Cycles
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Solution Overview
Problem
Current hydrogen liquefaction technologies face challenges in achieving efficient and economical large-scale production due to limitations in energy efficiency, capital costs, and operational complexity, particularly in designing efficient turbo-expanders and compressors, and the need for multiple refrigerant components that increase inventory and storage requirements.
Innovation Solution
A novel cascade process utilizing two closed cooling cycles with neon and hydrogen/helium refrigerant streams to achieve efficient hydrogen liquefaction, reducing specific energy consumption and operational costs, and simplifying the plant design by using commercially available equipment and minimizing the number of rotating machines and refrigerant components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydrogen liquefaction processes are used, then hydrogen can be liquefied, but energy consumption is high and production capacity is limited
Solution Approach 1:
The liquefaction process is divided into multiple independent cooling stages, each handling a specific temperature range. The first cooling stage handles precooling from ambient to intermediate temperature, while the second stage handles final cooling to liquefaction temperature. This segmentation allows each stage to be optimized independently, improving overall energy efficiency and enabling larger production capacities without proportionally increasing energy consumption.
Solution Approach 2:
An intermediate cooling stage is introduced between the precooling stage and the final liquefaction stage. This intermediate stage uses a refrigerant cycle that operates at moderate temperatures, serving as a bridge that reduces the temperature differential requirements for both the precooling and final cooling stages, thereby reducing the total work required by compressors and expanders.
2Loss of energy
If multiple refrigerant components are used, then cooling efficiency is improved, but inventory and storage requirements increase
Solution Approach 1:
The patent extracts and eliminates unnecessary refrigerant components from the system. Instead of using complex multi-component refrigerant mixtures, the invention uses simplified single-component refrigerants (nitrogen for precooling, hydrogen or helium for final cooling) that can achieve the same cooling effect with smaller inventories and simpler storage requirements.
3Temperature
If the number of rotating machines is increased, then cooling performance is improved, but operational complexity increases
Solution Approach 1:
The patent merges multiple cooling functions into fewer integrated machine units. The refrigeration systems are designed so that compressors and expanders handle multiple temperature levels through staged operation, reducing the total number of rotating machines required while maintaining or improving cooling performance through optimized thermodynamic cycles.
4Productivity
If conventional equipment is used, then plant design is straightforward, but production capacity is limited
Solution Approach 1:
The patent introduces dynamic operational modes that allow conventional equipment to operate at higher capacities. The system can switch between different operating configurations (e.g., single-stage or two-stage cooling modes, different refrigerant circulation rates) to adapt to varying production demands, enabling existing equipment to achieve 10-20 times higher production capacity through flexible operational control rather than through complex equipment design.
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 process achieves thermodynamically and economically efficient hydrogen liquefaction with production capacities up to 10 to 20 times higher than conventional systems, reducing specific energy consumption and operational complexity while maintaining high hydrogen purity and reducing equipment and refrigerant requirements.
Implementation Method 1
said first refrigerant stream is expanded, thereby producing cold
Implementation Method 2
said second refrigerant stream is expanded, thereby producing cold
Implementation Method 3
the feed gas stream is precooled to the intermediate temperature in a precooling step yielding a precooled feed gas stream, and the precooled feed gas stream is contacted with a catalyst in a catalytic conversion step, thereby converting ortho hydrogen comprised within the precooled feed gas stream to para hydrogen
Data Source
AI summary
The present invention relates to a method for liquefying hydrogen in large-scale comprising the steps of: providing a feed gas stream comprising hydrogen, precooling the feed gas stream to an intermediate temperature yielding a precooled feed gas stream, cooling the precooled feed gas stream to a temperature of below the critical temperature of hydrogen yielding a liquid product stream comprising hydrogen. According to the invention, the precooled feed gas stream is cooled to a first temperature in a first cooling step by a first closed cooling cycle with a first refrigerant stream consisting of or comprising neon and/or hydrogen, and that the cooled feed gas stream is further cooled from the first temperature to temperature below the critical temperature of hydrogen in a second cooling step by a second closed cooling cycle with a second refrigerant stream comprising or consisting of hydrogen and/or helium