Page 29 - Phelan Energy Green Ammonia Plant Egypt

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Manufacturing Process Components
Electrolyzer
Electrolyzers are used for producing green hydrogen by electrolysis of water using renewable energy, generating hydrogen at the cathode and oxygen at the anode.
The various electrolyzer technologies available are:
Alkaline Water Electrolysis
PEM Water Electrolysis
SOEC Water Electrolysis
•Alkaline electrolyzers use a liquid alkaline solution of sodium or potassium hydroxide as the electrolyte and mostly nickel-based plates as electrodes •The technology is well established and mature and therefore presents relatively low risks
•It does not require a catalyst or scarce materials for hydrogen production
•These electrolyzers are most competitive in terms of capital cost requirements. However, they face the major issue of limited part-load range due to
increased gas impurity at low power availability
•PEMs use a polymer perfluoro sulfonated acid type as the electrolyte and expensive noble metal catalysts such as platinum and iridium as electrodes •These electrolyzers have a compact design as compared to the alkaline ones
•PEMs can operate at low loads and quicker response time
•Though expensive as compared to the alkaline ones, their higher energy efficiency helps reduce the O&M costs over the plant life
•SOEC Water Electrolysis utilizes a solid ceramic material as the electrolyte and the process is carried out at high temperatures •Advantages include high efficiencies, long-term stability, fuel flexibility, low emissions, and low operating costs
•The greatest disadvantage is the high operating temperature
•SOEC electrolyzers are currently under investigation and are not commercially applied for use
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