Industrial water management: Paving the way for new processes, sustainable production and site security

The utilisation of renewable energies and their storage in the form of hydrogen or derived products is one of the most important prerequisites for a climate-neutral process industry. A growing number of initiatives in various sectors are accelerating the expansion of capacities to produce and utilise hydrogen: More than 1,400 international hydrogen projects, as well as many reference projects in Germany such as Aquaventus, H2Giga, H2Mare or Kopernikus emphasise this development. While industry uses hydrogen as an energy storage medium or for high-temperature processes, R&D projects are focussing on hydrogen infrastructure, mass production of electrolysis technologies and the synthesis of basic chemicals based on hydrogen.

Commercially available electrolysers require around 10 to 17 kilograms of deionised water to produce one kilogram of green hydrogen. Green or sustainable energy, the basis for green hydrogen, can be produced particularly economically in sunny or windy regions. However, the regions with the highest potential for renewable energies are usually also the regions where there is a high level of water stress and therefore a water risk. Once the local resources have been used up, this has an irreversible impact on the region. Alternative water resources for hydrogen production are therefore becoming increasingly important. Examples include desalinated water and water reuse. A growing number of seawater desalination plants leads to new challenges in terms of wastewater discharge (emissions into the sea) and opens up opportunities for the utilisation of brines and concentrates, for example. The production of green hydrogen will increase in the future. As a result, water will have to be utilised and reused more efficiently in the production process, especially cooling water and wastewater streams. This is where optimised, integrated water management comes into play.

More and more new hydrogen projects are focussing on a direct conversion of hydrogen into basic chemicals and chemical energy storage, such as ammonia, methane or eKerosene. The thermal energy released in this production step can be made available to other processes. Thermal desalination technologies with higher efficiency, as well as biological wastewater treatment, can thus benefit from the available thermal energy and move further into focus. This development is not only relevant for the hydrogen economy; new membrane separation processes or extensions to biological water treatment can also have a positive impact on industrial water management in terms of process and energy efficiency. 

"Water is the key to realising large-scale plants for the production of green hydrogen and its downstream products such as methanol or ammonia. That's why we need to think about integrated water management together with strategies for renewable energies and hydrogen production right from the start. This is the basis for a successful green hydrogen economy. Plant engineering and process technology, as we will see at ACHEMA 2024, will make a decisive contribution to this," says Dr Thomas Track, Head of the Water Management Subdivision at DECHEMA e.V.

In addition to renewable energies, efficient and robust water-related solutions are therefore needed:

• Expertise and planning to produce hydrogen / follow up PtX products and water management must go hand in hand.
• (Wastewater) treatment technologies and management concepts must be tailored to inland, coastal and marine production scenarios.
• The recycling of water and material flows must be optimised.