Technology
Anyone Anywhere Can Utilize Hydrogen
What is PEM ?
- PEM is called Polymer Electrolyte Membrane
- When electricity is applied by electrolyzing pure water to produce hydrogen, water molecules are decomposed and oxidized into oxygen and hydrogen ions, and hydrogen ions pass through the stack meet electrons and reduce hydrogen to hydrogen, which does not emit greenhouse gases or air pollutants.
PEM has the advantages of high current density, high energy efficiency, miniaturization, maintenance and high-purity hydrogen production, and high cost due to the use of platinum and iridium.
What is an alkaline ?
- Alkaline water electrolysis is a green hydrogen production method that produces hydrogen in the same manner as PEM by electrolyzing water using a high concentration of potassium hydroxide (KOH) electrolyte.
- Alkaline water electrolysis is used by many domestic and foreign companies due to its low facility cost and suitable for large capacity , but it is bulky and has a problem of efficiency degradation, and product corrosion due to the use of KOH
Comparison of PEM & Alkaline Water Electrolysis Techniques
| Category | PEM | Alkaline |
|---|---|---|
| electrolyte | cation exchange membrane | potassium hydroxide(KOH) |
| Elcetrode used (catalyst) | Pt(platinum),Ir(iridium) | Ni(nickel),Fe(iron) |
| Operating Temperature (⁰C) | 50 ~ 80 | 70 ~ 90 |
| Operating Pressure (bar) | <70 | <30 |
| Current Density(A/cm^2) | 1 ~2 | 0.2 ~ 0.8 |
| Facility efficiency (kWh/kg) | 50 ~ 83 | 54 ~ 73 |
| Life(h) | 90,000 | 20,000 |
| Stack unit (kW) | 1,000 | 1,000 |
| Stack Cost($/kW) | 400 | 270 |
| Facility Cost ($/kW) | 700 ~ 1400 | 500 ~ 1,000 |
| Cell Voltage (v) | 1.8 ~ 2.2 | 1.8 ~ 2.4 |
| Voltage efficiency (%) | 96 | 62 ~ 82 |
| Hydrogen purity (%) | 99.999 | 99.8 |
PEM Stack DRY CELL
- As a general method used in the green hydrogen production method, Dry cell has the advantage of being able to produce by separating or combining hydrogen and oxygen because it is produced by passing water through a stack
- However, it has the disadvantage that the device is complicated and consumes a lot of power due to the use of the motor as electrilyte storage containers, stacks, filters and motors are required.
ECO STAR Submerged Type PEM Stack
- The submerged PEM stack uses pure water as its raw material and generated hydrogen and oxygen at the +/- cathode of the separator.
- Since it is a method of generating and producing hydrogen in water, it has a great advantage of not having the risk of explosion.
- It can produce high-purity hydrogen and oxygen without the need for a separate purification device, and it is possible to produce high-efficiency hydrogen and oxygen and high-purity hydrogen and oxygen due to it’s high current density.
- In addition, it is a high-pressure hydrogen generating device that does not require a separate.
Electricity Required to Generate 1kg of Hydrogen
