In the evolving landscape of industrial power solutions, hydrogen-based stationary fuel cells are emerging as game-changers for facilities requiring reliable backup power. A recent technical whitepaper from Barksdale Control Products provides compelling insights into this transformative technology, with particular focus on the critical role of hydrogen gas pressure monitoring in Solid Oxide Fuel Cells (SOFCs).
The Shift Toward Sustainable Backup Power
Traditional industrial backup power has long relied on diesel generators—bulky, maintenance-intensive systems that release approximately 2.67kg of CO2 per liter of fuel burned. As sustainability initiatives gain momentum across industrial sectors, operations managers and engineers are seeking cleaner alternatives that don't compromise reliability.
Hydrogen fuel cell systems present a compelling solution. These systems can utilize hydrogen extracted from fossil fuels or, more promisingly, produced through electrolysis—splitting water into hydrogen and oxygen—resulting in carbon-free hydrogen production. When implemented as stationary power solutions, these systems deliver reliable backup electricity with zero emissions during operation.
What makes this technology particularly attractive for industrial applications is its versatility. These systems can function independently or integrate with renewable energy sources like solar panels and wind turbines, creating robust microgrids of locally-generated clean energy. For manufacturing facilities, agricultural operations, and processing plants where power interruptions can result in significant financial losses, this reliability factor is invaluable.
The Critical Role of Pressure Monitoring in Hydrogen Fuel Cells
The whitepaper highlights a crucial aspect of hydrogen fuel cell implementation that operations engineers must consider: precise pressure monitoring is essential for system efficiency, safety, and longevity.
For Solid Oxide Fuel Cells (SOFCs) to perform optimally, they require precisely controlled hydrogen pressure. Similarly, Proton Exchange Membrane Fuel Cells (PEMFCs) depend on proper water management and pressure monitoring to maintain appropriate hydration of the polymer electrolyte membrane, preventing issues like dehydration or flooding that can compromise performance.
Understanding the Technical Challenges
Implementing hydrogen pressure monitoring solutions presents unique challenges that standard pressure transducers cannot adequately address. The whitepaper identifies two primary technical hurdles:
1. Hydrogen Permeation
Hydrogen molecules can break down into ions that diffuse through metal isolation diaphragms used in conventional pressure transmitters. Over time, these hydrogen ions reform into molecules in the fill fluid, creating bubbles that cause measurement drift. In extreme cases, this can lead to physical expansion of the isolation diaphragm and ultimately result in diaphragm cracking.
For industrial applications where precise pressure measurements dictate system efficiency, this degradation in accuracy is unacceptable. Maintenance teams in continuous processing facilities understand that even minor measurement drift can lead to significant inefficiencies over time.
2. Metal Embrittlement
Perhaps more concerning for industrial implementation is the phenomenon of hydrogen embrittlement—where exposure to hydrogen causes certain metals to lose ductility and become brittle. High-strength steels, titanium, aluminum alloys, and electrolytic tough-pitch copper are particularly susceptible.
This degradation of mechanical properties can ultimately lead to component failure—a serious concern in high-pressure industrial hydrogen applications. The whitepaper notes that austenitic stainless steels, particularly 316Ti and 316L, show only minor low-temperature embrittlement, making them preferred materials for hydrogen applications.
Engineered Solutions for Hydrogen Pressure Monitoring
To address these challenges, Barksdale has developed specialized BHyT Fuel Cell hydrogen pressure transducers specifically designed for hydrogen applications. These "silent guardians" of fuel cell systems continuously monitor and adjust hydrogen pressure to ensure safe, efficient operation while maximizing performance and system lifespan.
The whitepaper details two sensing technologies employed in these transducers:
Gold-Plated Piezoresistive Transducers
These industry-standard transducers leverage gold plating to resist hydrogen permeation. The dense, inert nature of gold creates an effective barrier against hydrogen ions, significantly enhancing the transducer's durability and measurement accuracy in hydrogen environments.
316L One-Piece Monolithic Transducers
This newer technology offers robust performance with reduced risk of hydrogen embrittlement. Their weld-free design and thicker metal diaphragm simplify installation while providing greater resistance to hydrogen-related degradation.
Both technologies are pressure-tested during manufacturing to withstand high-pressure spikes without compromise. Using 316L stainless steel for wetted materials further enhances compatibility with hydrogen applications by minimizing embrittlement risks.
Technical Specifications Worth Noting
For engineers evaluating hydrogen fuel cell implementation, the transducer specifications are impressive:
- Pressure Range: 0-10,000 PSI (689 bar)
- Accuracy: ±0.1% FSO (Full Scale Output)
- Temperature Range: -40° to 125°C
- Response Time: < 3ms
- Proof Pressure: 2x
- Burst Pressure: 3x
- Agency Approvals: UL, CML, CSA, EMI/EMC (per IEC 61000)
These specifications ensure the transducers can handle the demands of industrial hydrogen applications while maintaining the precision required for optimal fuel cell operation.
Real-World Applications in SOFCs
The whitepaper outlines two key applications for pressure transducers in Solid Oxide Fuel Cell systems:
SOFC Stack Fuel Pressure Monitoring
Pressure transducers monitor the pressure of hydrogen or natural gas entering the SOFC stack. Maintaining stable fuel pressure is essential for efficient electrochemical reactions within the fuel cell, optimizing performance while preventing potential system damage.
Fuel and Air Manifold Pressure Monitoring
Pressure transducers also monitor pressures in both fuel and air manifolds that supply gases to each cell within the SOFC stack. This monitoring ensures uniform gas distribution, which maintains consistent performance across all cells in the fuel cell. Proper pressure balance achieves optimal efficiency and reliability while preventing variations that could lead to uneven cell performance or damage.
Proven Performance in Transportation Applications
Although the whitepaper focuses primarily on stationary applications, it's worth noting that Barksdale's BHyT Fuel Cell Transducers have demonstrated their reliability in mobile hydrogen applications as well. For the past four years, these transducers have been used in hundreds of hydrogen-powered forklifts and public transit buses.
In hydrogen-powered buses, the transducers serve dual purposes:
- High-pressure monitoring in roof-mounted hydrogen storage tanks at up to 6,500 PSI (448 bar) using monolithic sensing technology
- Low-pressure monitoring of hydrogen intake into fuel cells at up to 200 PSI (14 bar)
This proven track record in transportation applications—where vibration, temperature fluctuations, and operational stresses are typically more severe than in stationary applications—speaks to the robustness of these monitoring solutions.
Implementation Considerations for Industrial Facilities
For operations managers and engineers considering hydrogen fuel cell implementation at industrial facilities, several factors merit consideration:
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Integration with existing systems: Hydrogen fuel cells can supplement current power infrastructure, providing cleaner backup power without necessitating complete system overhauls.
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Scalability: Systems can be scaled to meet specific facility requirements, from small backup applications to larger primary power generation.
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Maintenance requirements: While hydrogen systems generally require less maintenance than diesel generators, specialized monitoring equipment like the BHyT transducers helps ensure optimal system performance and early problem detection.
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Safety protocols: Proper pressure monitoring is not just about efficiency—it's a critical safety consideration when working with hydrogen.
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Long-term cost benefits: Though initial implementation costs may exceed traditional systems, reduced emissions, potential regulatory compliance benefits, and operational efficiencies can deliver long-term cost advantages.
The Future of Industrial Power
The whitepaper concludes with an outlook on the future of hydrogen sensing technology, emphasizing the importance of continued innovation in materials and sensor designs. These advancements will be crucial for ensuring the safe and efficient utilization of hydrogen as industries transition toward more sustainable energy solutions.
For industrial facilities facing increasing pressure to reduce carbon footprints while maintaining reliable operations, hydrogen fuel cell systems represent a promising path forward. The technology allows operations to maintain or even enhance power reliability while simultaneously advancing sustainability initiatives—a rare win-win in industrial operations.
As sensor technology continues to evolve and address the unique challenges of hydrogen environments, we can expect wider adoption of these systems across industrial sectors, further accelerating the transition to cleaner, more sustainable industrial power solutions.
The detailed insights provided in Barksdale's whitepaper offer valuable guidance for engineers and operations managers navigating this technological shift, underscoring the critical importance of precise pressure monitoring in unlocking the full potential of hydrogen as a clean industrial power source.