Mixed Refrigerant Composition for Low-Cost Hydrogen Precooling
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Solution Overview
Problem
Current hydrogen liquefiers face inefficiencies in energy consumption and operational costs due to high operating costs from using liquid nitrogen as a refrigerant, particularly at larger scales, and existing designs for precooling cycles are complex and costly, limiting the upscaling of hydrogen liquefaction plants.
Innovation Solution
A refrigerant composition comprising an inert gas and a mixture of C1-C5 hydrocarbons, optimized for closed-loop Joule-Thomson refrigeration cycles, which reduces specific energy consumption and capital costs by achieving efficient precooling temperatures between 80 K and 125 K, using a mixture of nitrogen, argon, methane, ethane, and hydrocarbons like n-butane and isopentane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid nitrogen is used as refrigerant for precooling hydrogen feed stream, then precooling temperature can be achieved, but plant operating costs significantly increase
Solution Approach 1:
The invention changes the composition parameters of the refrigerant from pure nitrogen to a mixed refrigerant containing C1-C5 hydrocarbons and nitrogen in specific proportions. This parameter change allows the refrigerant to achieve the same precooling temperature while reducing the amount of refrigerant needed and lowering operating costs, as the hydrocarbon components have different thermodynamic properties that improve cooling efficiency
Solution Approach 2:
The invention uses a composite refrigerant mixture combining C1-C5 hydrocarbons (methane, ethane, propane, butane, pentane) with nitrogen in specific proportions. This composite material leverages the complementary properties of each component - the hydrocarbons provide efficient heat transfer and the nitrogen provides inertness - to achieve cost-effective precooling while maintaining safety and performance
2Use of energy by moving object
If mixed-refrigerant cycles are designed for high precooling temperatures, then precooling efficiency increases, but the cooling duty shifts to colder, more inefficient refrigeration cycles
Solution Approach 1:
The invention optimizes the refrigerant composition parameters to achieve precooling temperatures in the range of 80-125 K, which is lower than conventional mixed-refrigerant cycles. This parameter change allows more cooling duty to be performed at warmer temperatures where efficiency is higher, reducing the burden on colder, less efficient parts of the refrigeration system
3Use of energy by moving object
If precooling refrigerant mixtures with five or more fluid components are used, then precooling performance improves, but operational complexity and handling requirements increase
Solution Approach 1:
The invention reduces the number of refrigerant components from five or more to exactly five specific components (C1, C2, C3, C4, C5 hydrocarbons with nitrogen) in optimized proportions. This parameter simplification maintains precooling performance while significantly reducing operational complexity, storage requirements, and handling difficulties compared to multi-component mixtures
Solution Approach 2:
The invention extracts and removes unnecessary components from complex multi-component refrigerant mixtures, retaining only the essential C1-C5 hydrocarbons and nitrogen in optimized proportions. This extraction eliminates the need for additional storage vessels and simplifies make-up systems while maintaining the thermodynamic performance needed for effective precooling
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 proposed refrigerant composition reduces specific energy consumption by up to 30% compared to prior technologies, enabling economical large-scale hydrogen production with simpler plant designs and reduced operational complexity.
Implementation Method 1
The hydrogen feed stream is precooled from ambient temperature to approximately 80 K by evaporating a liquid nitrogen stream
Implementation Method 2
the hydrogen feed stream is precooled from ambient temperature to approximately 80 K by evaporating a liquid nitrogen stream
Implementation Method 3
by evaporating a liquid nitrogen stream
Implementation Method 4
optimized for closed-loop Joule-Thomson refrigeration cycles, which reduces specific energy consumption and capital costs by achieving efficient precooling temperatures between 80 K and 125 K
Data Source
AI summary
The present invention relates to a refrigerant composition. According to the invention it is envisioned that the composition comprises comprising an inert gas selected from nitrogen, argon, neon and a mixture thereof, and a mixture of at least two C1-C5 hydrocarbons. The present invention further relates to the use of the refrigerant composition in a method for liquefying a gaseous substance, particularly hydrogen or helium.