Cryo-Adsorber Hydrogen Cooling via Joule-Thomson Expansion
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Solution Overview
Problem
Existing hydrogen storage systems for vehicles face challenges in efficiently converting compressed hydrogen gas or liquid hydrogen to the optimal temperature and pressure conditions required for rapid adsorption by high surface area adsorbent materials like MOFs, leading to high recirculation rates and increased costs due to the need for high feed flow rates during refueling.
Innovation Solution
The system employs liquid nitrogen for cooling and Joule-Thompson expansion to sub-cool hydrogen gas to below 80K, reducing recirculation rates and feed flow requirements by throttling hydrogen from high pressure to 20 bar, and uses liquid hydrogen for further cooling to enhance adsorption efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If compressed hydrogen gas is cooled to cryogenic temperatures for adsorption, then adsorption efficiency is improved, but cooling cost and system complexity increase
Solution Approach 1:
The patent applies parameter changes by utilizing the Joule-Thomson effect to convert pressure energy into cooling effect. Hydrogen gas is expanded from high pressure (350-450 bar) to low pressure (20 bar) through a throttling valve, causing temperature drop from ambient to below 80K. This parameter transformation eliminates the need for external cryogenic cooling systems while achieving the required adsorption temperature.
Solution Approach 2:
The system uses the hydrogen gas itself as the cooling medium through self-cooling during throttling expansion. The hydrogen undergoes adiabatic expansion and cools itself without requiring external refrigeration equipment. The cooled hydrogen then serves dual purposes: it is the cooling agent and simultaneously the adsorbate for storage.
2Productivity
If high feed flow rates are used during refueling, then refueling speed is improved, but recirculation rates and operating costs increase
Solution Approach 1:
The system performs preliminary cooling of hydrogen gas to cryogenic temperatures before adsorption. By pre-cooling the hydrogen to below 80K through Joule-Thomson expansion, the adsorbent material can rapidly adsorb hydrogen at high flow rates without requiring recirculation for temperature control. This preliminary temperature preparation eliminates the need for energy-intensive recirculation during refueling.
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 approach significantly reduces hydrogen recirculation rates and feed flow rates, enabling faster refueling while maintaining hydrogen purity and efficiency, thus lowering capital and operating costs for fuel stations.
Implementation Method 1
the hydrogen stream is cooled with liquid nitrogen to below about 80 K.
Implementation Method 2
Joule-Thompson expansion to sub-cool hydrogen gas to below 80K
Implementation Method 3
The hydrogen may then be cooled by heat exchange with liquid hydrogen.
Implementation Method 4
Hydrogen gas under pressure and at a suitably cold temperature may be brought into contact with the adsorptive particles and stored under pressure in the porous material.
Data Source
AI summary
Hydrogen gas at a hydrogen refueling site is cooled below liquid nitrogen temperature (e.g., about 80K) for more efficient adsorption of hydrogen on hydrogen adsorbent particles in the fuel storage of a hydrogen powered vehicle. When compressed hydrogen gas is available it may be cooled with liquid nitrogen and then sub-cooled below about 70K by a Joule-Thompson expansion. When liquid hydrogen provides hydrogen gas it may be cooled below liquid nitrogen temperatures by mixing with liquid hydrogen or by heat exchange with liquid hydrogen.