Green hydrogen plays a crucial role in the global transition to sustainable energy and zero-emission economies. However, producing green hydrogen requires high-purity water. In this article, Lee Underwood, Director of Engineering and Industrialisation for Veolia Water Technologies UK, takes a closer look at our packaged water treatment systems that can ensure a reliable and consistent supply of hydrogen.
Green hydrogen is produced through electrolysis, a chemical process that uses an electrical current to separate hydrogen from oxygen in water. When the electricity used in electrolysis comes from renewable sources, no carbon emissions are released into the atmosphere.
The reaction itself takes place in an electrolyser. If the water used for hydrogen production is not adequately treated, ions like iron, nickel and chromium may damage the electrolyzer, leading to decreased efficiency and the need for replacement.
Therefore, it is crucial for hydrogen producers to select reliable water treatment systems that consistently provide water with a purity of at least 1MΩ.cm, which is the required level for hydrogen production.
Another important consideration is the ability to produce hydrogen in a variety of locations and environments. Standard electrolyzer designs face challenges in adapting to different environments while maintaining effectiveness. This is because different sources of feedwater — such as seawater, river water, boreholes, wastewater or town mains feed — require different water treatment technologies to achieve the necessary water quality.
Pretreatments may include particle filtration, water softening, organic scavengers, granulated activated carbon (GAC) filters, antiscalant dosing or degassing systems. The water then goes through a reverse osmosis (RO) system before being polished with mixed bed ion exchange or continuous electrodeionization (CEDI).
Veolia Water Technologies has used its expertise to design a range of plug-and-play products that incorporate various technologies within a single unit, providing a reliable water supply suitable for hydrogen production. These solutions vary depending on the application.
Let’s explore them further:
Smaller applications: 100 kW – 1 mW
Our Elga® product range is ideal for electrolyzers between 100 kilowatts (kW) and 1 megawatt (mW).
The Elga product range focuses on human-led design and, combined with our global service network, offers service packages to ensure the availability and efficiency of electrolyzers, crucial for the commercial success of green hydrogen.
Larger applications: 1mW – 500mW
We also offer packaged water treatment systems for electrolyzers between 1 mW and 20 mW, typically used for industrial applications.
Our Sirion™ range of compact RO systems produces pure water with a low footprint, ranging from 10 l/h to 120 m3/h. These fully-automatic systems use low-energy membranes to achieve high salt rejection. The Sirion Seawater variant is specifically designed to treat seawater, rejecting over 99% of salt contained in the feedwater. Standard systems have flow rates ranging from 1 to 31 m3/h.
The Sirion Midi processes between 90 to 800 l/h and can handle total dissolved solids (TDS) levels of up to 1,000 mg/l. It features four low-energy membranes and a rotary vane pump, making it suitable for smaller industrial applications.
For larger projects, we offer Terion® and Terion S, which utilize RO and CEDI to provide high-quality demineralized water that prevents scale and corrosion. Terion removes over 99.9% of dissolved inorganics to produce the highest specification of demineralized water and is available in five single skid-mounted units, while Terion S comes in seven skid-mounted models.
For projects with electrolyzers ranging from 100 kW to 500 mW, we can design and deliver customized systems. Ultimately, we offer packaged solutions that include all the water treatment technologies a site requires in a single unit or multiple connected systems. Additionally, our global service team ensures that our products operate at their maximum capabilities throughout the electrolyzer’s lifespan.