adminELECTROLYZER
An electrolyzer produces hydrogen and oxygen gas by splitting water molecules using electricity in a process called electrolysis.
There are several types of electrolyzer and they are; alkaline, proton (PEM), solid oxide (SOEC) and anion exchange membrane (AEM) electrolyzer.
Alkaline electrolyzer uses a liquid alkaline solution typically potassium hydroxide (KOH), as the electrolyte. In this process water is fed into the electrolyzer and mixed with the alkaline solution then an electric current is applied causing the water to split into hydrogen and oxygen. Example of alkaline electrolyzer includes; siemens alkaline electrolyzer.
Proton exchange membrane (PEM) electrolyzer uses a dolid polymer electrolyte , typically a fluorinated sulfonic acid polymer to facilitate the electrolysis of water. In this process water is fed into the electrolyzer and comes into contact with the proton exchange membrane, then an electric current is applied causing the water to split into hydrogen and oxygen. Example of a PEM electrolyzer includes; Ballard power systems PEM electrolyzer.
Solid oxide electrolyzer (SOEC) uses a solid oxide material as the electrolyte and operates at high temperatures from 600 to 1000 degrees centigrade. In this process, water is fed into the electrolyzer and comes into contact with the SOEC, and then an electric current is applied causing the water to split into hydrogen and oxygen gas. Example of SOEC electrolyzer includes; Bloom energy SOEC
Anion exchange membrane (AEM) electrolyzer uses an anion exchange membrane as the electrolyte and operates at room temperature. In this process water is fed into the electrolyzer and comes into contact with the AEM, and then an electric current is applied, causing the water to split into hydrogen and oxygen gas. Example of AEM electrolyzer includes; ITM power’s AEM electrolyzer.
The advantages of electrolyzers are; electrolyzers produce hydrogen through electrolysis, which does not emit greenhouse gases. Electrolyzers can be powered by various energy sources including renewable energy systems like wind and solar. Electrolyzers can produce high purity hydrogen (up to 99.9999%) without the need for additional processing. Electrolyzers can be designed for small scale portable applications or large scale and industrial applications. Electrolyzers have low operatin costs as they do not require fuel or raw materials and have few moving parts. Electrolyzers help to absorb excess renewable power thus acting as a form of energy storage. Electrolyzer decouples hydrogen production from fossil fuel sources thereby improving energy security and independence. Electrolyzers only need water and electricity to produce two important by products oxygen and hydrogen.
The disadvantages of electrolyzers are;Electrolyzers can be expensive to procure and install especially for large scale applications. Electrolyzers require a significant amount of cheap energy to operate satisfactorily and economically. Electrolyzers have a limited lifespan typically ranging from 5 to 10 years. Electrolyzers can be prone to corrosion and other durability issues, particularly in harsh environments. Electrolyzers requires purified water which can be a constraint in water scarce regions.
The applications of electrolyzers are as follows; electrolyzers are used to produce hydrogen and oxygen for fuel cell vehicles. Electrolyzers are used in various industrial processes to produce chemicals, fuels and fertilizers. Electrolyzers are used to store excess energy from renewable energy sources and balance grid energy supply. Electrolyzers are used in power to gas (P2G) applications to convert excess electrical energy into hydrogen which can be injected into natural gas pipelines or stored for later use. Electrolyzers are used in space exploration to produce oxygen and hydrogen for life support systems and propulsion. electrolyzers can be used to produce hydrogen and oxygen for numerous industrial applications such as steel, agriculture, medical etc.
The future of electrolyzers is based on the advances and development of the following technologies; research is ongoing to improve the efficiency of electrolyzers in order to reduce energy consumption and costs. Advances in design efforts to reduce the capital cost of electrolyzers to make them scalable and cost competitive are ongoing. Electrolyzers will no doubt play a crucial role in the transistion to a low carbon economy so cost and efficiency is a major driving for in R and D efforts globally. Electrolyzers will be increasingly be integrated with renewable energy sources, enabling low carbon economy with the production of hydrogen and oxygen to support the development of sustainable energy systems. Electrolyzers are expected to find new applications in industries such as carbon capture, utilization, and storage and bio-based applications.
SOURCES:
- Water electrolysis for hydrogen production by Pasquale Cavaliere.
- Green hydrogen production by water electrolysis by Junbo Hou, Ming Yang et.al.
- Electrochemical water electrolysis: fundamentals and technologies by Lei Zhang, Hongbin Zhao, David P. Wilkinson, Xueliang Sun, Jiujun Zhang.
- Electrolyzers: Design, operation and applications by S.S.H Rezaee and M.M Forss.
- Electrolysis: Principles, procedures and applications by J.M Bockris and A.K.N Reddy.
