High-Pressure Hydrogen Supply Without Compressors Using Formic Acid
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Solution Overview
Problem
Hydrogen stations require high-pressure hydrogen of 82 MPa or more for fuel-cell vehicles, which cannot be directly purified and re-compressed efficiently without using compression machines, leading to high costs and reduced system efficiency.
Innovation Solution
A pump-less high-pressure hydrogen supply system utilizing the dehydrogenation reaction of formic acid to produce a mixed gas of hydrogen and carbon dioxide, followed by separation and purification using pressure swing adsorption, allowing for the generation of high-pressure hydrogen without compressors, with energy recovery through adiabatic expansion and phase separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-pressure hydrogen is obtained by conventional purification and compression methods, then high-purity hydrogen can be supplied, but compression machines are required which increase system cost and reduce efficiency
Solution Approach 1:
The invention changes the pressure parameter throughout the system by conducting dehydrogenation at high pressure (5-200 MPa) and maintaining high pressure through phase separation and PSA purification, eliminating the need for compression machines and achieving pump-less high-pressure hydrogen supply
Solution Approach 2:
The invention replaces mechanical compression systems with a chemical reaction-based pressure generation system where formic acid dehydrogenation occurs at high pressure, and pressure is maintained through phase separation and adsorption processes rather than mechanical compression
2Stress or pressure
If dehydrogenation reaction is conducted at high pressure, then high-pressure mixed gas is obtained, but mist component is generated which reduces system efficiency
Solution Approach 1:
The invention extracts and removes the harmful mist component from the high-pressure mixed gas through phase separation, separating the mist (containing water, formic acid, and catalyst) from the hydrogen-rich gas phase, thereby eliminating the harmful effect while maintaining high pressure
Solution Approach 2:
The invention uses phase separation as an intermediary process between dehydrogenation and purification, where the mist component is separated through phase change, allowing the hydrogen-rich gas to proceed to PSA purification without the harmful mist
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 system efficiently supplies high-pressure hydrogen to fuel-cell vehicles at 70 MPa or more with high purity and low energy consumption, eliminating the need for compressors and achieving high system efficiency.
Implementation Method 1
the mixed gas is cooled by a separator with a pressure being kept at 0.4 MPa or more, and thus a gas component other than hydrogen is removed as a liquid or a solid by phase separation
Implementation Method 2
the mixed gas from which the mist component is removed is cooled by cold energy obtained by adiabatic expansion of at least one or more selected from the group consisting of a gas, a liquid, and a solid, containing mainly carbon dioxide removed by phase separation
Implementation Method 3
a mixed gas of hydrogen and carbon dioxide is obtained by dehydrogenation reaction of formic acid by use of a complex catalyst
Implementation Method 4
hydrogen separated is increased in purity by pressure swing adsorption
Data Source
AI summary
A purpose of the present invention is to provide a pumpless high-pressure hydrogen supply system capable of supplying high-pressure hydrogen to a fuel cell vehicle, etc., when needed without using a compressor or the like, and a method for the system. The present invention relates to a high-pressure hydrogen supply system that obtains a mixed gas of hydrogen and carbon dioxide by dehydrogenation of formic acid using a complex catalyst, separates the hydrogen therefrom, and supplies the hydrogen at a pressure of 5 MPa or more. By obtaining the mixed gas at a pressure of 5 MPa or more by dehydrogenation and cooling the mixed gas by a separator while maintaining this pressure at 0.4 MPa or more, gas components other than hydrogen are phase separated as liquids or solids and removed. The separated hydrogen is raised in purity by pressure fluctuation adsorption, continuously sent to a pressure accumulator, and stored at a pressure of 70 MPa or more.