It is very difficult to find water in suitable conditions for its different uses in industry. The quality requirements vary greatly depending on the industrial activity to be carried out. To adapt the characteristics of the water to the productive process, it is necessary the installation of Water Treatment Plants.
ImWater, thanks to its years of experience in the sector and the great work team behind it, specializes in the execution of turnkey projects of water treatment plants. Always looking for the best solution for the client, focusing on economic and operational optimization, as well as sustainable management of resources.
In this post, we want to delve into the use of water to minimize greenhouse gas emissions, particularly through the use of hydrogen.
Hydrogen
Thanks to Foro Nuclear we are going to know a little about Hydrogen from the point of view of Chemistry.
Hydrogen is the first element of the periodic table, it is the lightest chemical element that exists, its atom is formed by a proton and an electron and it is stable in the form of a diatomic molecule (H2), in normal conditions we can find it in gaseous state, it is tasteless, colorless and odorless.
Hydrogen is not a fuel that can be taken directly from nature because although it constitutes approximately 75% of the matter in the Universe, it is combined with other elements such as oxygen forming water molecules, or carbon, forming organic compounds. For this reason it is necessary to obtain it through different processes, which we will mention below.
Hydrogen Production
There are different methods of hydrogen production. It can be produced from different raw materials, different energy sources and by different processes.
Depending on the raw material and the energy source used to produce it, we can speak of 100% renewable, 100% fossil or hybrid processes in a certain percentage.
The simplified hydrogen chain: from production to usages
We should mention that, of all the methods of obtaining hydrogen, the cleanest is its production through water, since it does not emit CO2 in its production process. Since this process requires the use of energy, the more renewable the energy source used in the electrolysis of water, the greener the hydrogen is considered, giving rise to the well-known Green Hydrogen.
Not forgetting that, thanks to its status as an energy vector, the hydrogen thus obtained can be converted back into electrical energy through the use of fuel cells.
Water requirements associated with electrolyzers
The electrolyzer is a device for producing hydrogen by electrolysis, capable of separating the hydrogen and oxygen molecules of which water is composed using electricity. There are different types of electrolyzers, but they all have in common that they require ultrapure water.
At the international level, there are different organizations that have set the quality standards for purified water, among which the following stand out:
- American Society for Testing and Materials – ASTM D1193 2011
- International Organization for Standardization – ISO 3696
- Clinical and Laboratory Standards Institute – CLSI NCCLS
- Pharmacopea Europea y Pharmacopea Americana – EP y USP
We indicate the quality of the inlet water to the electrolyzer according to the American Society for Testing and Materials (ASTM) Standard, which refers to the water used as a reagent, classifying it into four different types of water, as well as the procedures for obtaining it.
Most commonly, in the case of electrolyzers, the water is type I water:
| Parameter | Type I | Type II | Type III | Type IV |
| Electrical Conductivity Max. (µS/cm @ 25ºC) | 0,056 | 1,0 | 4,0 | 5,0 |
| Electrical Resistivity (MΩ-cm @ 25ºC) | 18,2 | 1,0 | 0,25 | 0,2 |
| pH at 25ºC | – | – | – | 5,0 – 8,0 |
| TOC máx. (µg/L) | 10 | 50 | 200 | n/a |
| Sodium máx. (µg/L) | 1 | 5 | 10 | 50 |
| Total Silica max. (µg/L) | 3 | 3 | 500 | n/a |
| Chlorides max. (µg/L) | 1 | 5 | 10 | 50 |
| Endotoxins IU/ml | < 0.03 | < 0.25 | – | – |
In order to obtain this type of ultrapure water, it is necessary to manufacture a water treatment plant whose treatment process will be determined by the quality of the feed water and the volume of water to be fed to the electrolysis process.
In general terms, the treatment will be
- Pretreatment
- Reverse Osmosis (RO)
- Electrodeionization (EDI)
