Alkaline elektrolyseur
In reality, a lot of property interplays are at work.
Questions to ask when Choosing Separators for Alkaline Water Electrolyzers
✅ What is the ion conductivity of the separator?
✅What is the separator's bubble point pressure?
✅Is the separator chemically stable in concentrated KOH solutions?
✅How does the separator perform at temperatures around 80 °C?
✅What is the separator’s pore size distribution?
✅Is the separator hydrophilic enough?
✅Is the separator mechanically strong enough to withstand operating pressures?
✅How long is the expected lifespan of the separator under typical operating conditions?
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Introduction
The global push towards decarbonization has put green hydrogen firmly in the spotlight.
Alkaline electrolysers fit well here, given their stability and compatibility with large-scale operations.
4. Impurities in the water or electrolyte can poison catalysts, increase resistance, or cause side reactions, degrading performance and lifespan.
In general, alkaline and pressurized alkaline electrolyzers are the best fit for most applications.
The polymer binder creates a highly interconnected inorganic–organic porous structure, while the ceramic nanoparticles provide hydrophilicity, improving ion conduction within the separator.
When used for electrolysis, porous separators need to meet these two performance requirements:
LOW OHMIC RESISTANCE
They must have low ohmic resistance to facilitate ion transport across the electrodes and maintain electroneutrality between the cathode and anode.
HIGH BUBBLE POINT PRESSURE
They must have high bubble point pressure or the minimum pressure of gas to penetrate the separator to avoid the crossing over and mixing of product gases.
Of course, these two requirements only touch the surface.
While PEM offers a smaller footprint, its small stack size makes it suitable for only more specialized instances where there is no need to scale or deploy a large number of electrolyzers.
What Are Alkaline Electrolysers?
Alkaline electrolysers are electrochemical devices that use alkaline electrolysis to split water (H₂O) into hydrogen (H₂) and oxygen (O₂) gases.
As innovation continues, expect alkaline electrolysers to become even more efficient and adaptable, solidifying their position as a workhorse for a sustainable future.
FAQs for the Alkaline Electrolyser Article:
- Q: How efficient are alkaline electrolysers?
- A: Alkaline electrolyser system efficiency (converting electricity to hydrogen’s energy content) typically ranges from 60% to 75% (LHV basis), depending on design, operating conditions, and current density.
Energy Storage and Power-to-Gas Applications
Renewable energy companies use hydrogen as a storage medium, converting excess electricity from wind or solar into hydrogen for later use. In addition, PEM electrolyzers require the use of fluoropolymers to separate the electrodes. It features a smaller footprint and produces output at purity levels that meet exceptionally stringent requirements.
Fluoropolymers belong to a class of chemicals called per-and polyfluoroalkyl substances (or PFAS).
Alkaline Electrolyzers
Formally, water electrolysis is the process of splitting water into its constituent gases, H2 and O2, through the application of a direct current.
For larger applications, the cost of an Alkaline electrolyser will be drastically reduced to under $500 per kW.
While alkaline electrolysers are cost-effective at scale, it’s essential to consider the full lifecycle cost, including energy consumption, maintenance, and potential upgrades.
Alternatives to Alkaline Electrolysers
1.
They offer greater flexibility, more robust and reliable technology, and output that meets the needs of most industries. We strongly believe in the long-term potential of hydrogen as a clean energy solution.”
Download our Hydrogen Stack integration guide:
If you are working in an engineering company looking to become a Hydrogen Stack integrator our latest guide will be a high-value asset.
It provides the necessary ionic conductivity for the hydroxide ions to move between electrodes. And finally, while it features newer technology than alkaline electrolyzers do, it lacks field data on long-term degradation and has not yet been proven in large-scale projects. Those operating in the transport sector or other more specialized industries may find PEM to be the better choice.
Hydrogen can replace carbon in the blast furnace, drastically reducing carbon emissions while also yielding higher-purity steel with smaller carbon content and fewer impurities. However, they are still in the developmental stages for most large-scale applications and require extensive heat management. Electronics Manufacturing
In electronics, high-purity hydrogen is used for processes like silicon wafer production.
They are typically made of metals like nickel, often coated with catalysts (e.g., nickel alloys, cobalt oxides, platinum group metals in advanced designs) to lower the energy required for the reactions (reduce overpotential) and improve efficiency.
- Diaphragm/Separator: A porous layer positioned between the anode and cathode.
Minimizing distances and using highly conductive materials helps.
Advantages of Alkaline Electrolysers
- Mature Technology: Decades of industrial operation provide extensive experience and reliability data.
- Cost-Effective: Generally lower capital costs compared to other technologies like PEM, mainly due to the use of non-noble metal catalysts (nickel-based).
- Durability and Lifespan: Known for long operational lifetimes (often 60,000-80,000+ hours) when properly maintained.
- Scalability: Relatively easy to scale up to large industrial capacities (multi-megawatt systems).
Challenges and Disadvantages
- Lower Current Density: Typically operate at lower current densities than PEM electrolysers, meaning they require a larger footprint for the same hydrogen output.
- Limited Dynamic Operation: Can be slower to ramp up and down compared to PEM, which can be a disadvantage when directly coupled with variable renewable energy sources (like wind or solar).
When choosing between alkaline, pressurized alkaline, and PEM electrolyzers, make sure to take a holistic view that accounts for factors such as efficiency, cost, scalability, and suitability for your unique application.
If your organization is exploring the different types of electrolyzers available on the market, you may still feel overwhelmed by the options available to you.
At Stargate, our Alkaline electrolysers produce hydrogen at 32 bar with no need for external compressors.
Safety and Operational Insights
Alkaline electrolysers are robust but should be operated with standard industrial safety precautions. However, advancements are improving ramp rates.
- Gas Purity: Can have slightly higher gas crossover (H₂ in O₂ stream and vice-versa) compared to PEM, potentially requiring more extensive downstream purification for high-purity applications.
- Corrosive Liquid Electrolyte: Handling concentrated KOH or NaOH requires careful material selection and safety procedures.
At the heart of much current large-scale green hydrogen production lies a mature and reliable technology: the alkaline electrolyser.
- Diaphragm/Separator: A porous layer positioned between the anode and cathode.
- A: Alkaline electrolyser system efficiency (converting electricity to hydrogen’s energy content) typically ranges from 60% to 75% (LHV basis), depending on design, operating conditions, and current density.