Hydrogen peroxide (H₂O₂) plays a critical role across textiles, pulp and paper, and chemical manufacturing, where it is valued for its strong oxidising capability and clean decomposition to water and oxygen. Yet today’s dominant production process, the anthraquinone auto-oxidation process, is energy intensive, centralized, and dependent on fossil-fuel-derived hydrogen. To break this dependency, the HYPER project is developing a modular, fully electrochemical route for decentralised H₂O₂ production (e-H₂O₂).
A cornerstone of this effort is process modelling, the systematic prediction of mass flows, efficiencies, chemical processes, and scaling behaviour to guide the design of an electrochemical system capable of producing H₂O₂ on site, on demand. The combined efforts of all the project partners in the research, development and application successfully culminated in the design and construction of the project’s TRL 4/5 mini-plant, a crucial stepping stone toward industrial deployment. The recent delivery, installation, and operation of this mini-plant at the project’s textiles partner InoTex in the Czech Republic marks an important milestone in validating both the underlying chemistry and the process engineering assumptions that will ultimately shape the TRL 6 demonstration in 2026.
From Model to Reality: Realising the TRL 4/5 Mini-Plant
The installed system consists of two core units:
- Electrolyser: generates persulphate from a mixed ammonium sulphate and sulphuric acid anolyte.
- Utiliser: hydrolyses the electrochemically produced persulphate to form hydrogen peroxide.
The mini-plant operates in batch mode, consistent with modelling assumptions for early-stage validation: anolyte transfer, hydrolysis, product collection, and dosing were performed manually. This flexibility enabled testing across multiple bleaching technologies while generating accurate data for validating reaction kinetics, mass balances, and energy requirements.
Mini-plant Performance: Validating the Process Model
Extensive research has been done to determine the most energy and resource efficient process for the hydrolysis of persulfate to hydrogen peroxide. The hydrolysis process proceeds in four steps, as shown in Figure 1. The first step is an evaporator that concentrates the persulfate solution to the optimal concentration for further processing. Next is the actual hydrolysis reactor that produces hydrogen peroxide. The third step is a stripper that separates the hydrogen peroxide and can return the residuals back to the electrolyser. The final step is a distillation to provide the hydrogen peroxide concentration required by the end-user.
The electrolyte compositions, hydrolysis reaction and overall operating conditions tested directly mirrored those used in HYPER’s process design calculations. The results show a strong alignment between predicted and actual performance, confirming that the electrochemical and hydrolysis steps behave as expected under scaled conditions, an essential requirement before closing internal loops and progressing to semi-continuous operation.
Application Testing: Performance in Real Textile Bleaching
The HYPER process aims not only to produce e-H₂O₂, but to demonstrate its industrial relevance.
In laboratory bleaching tests with two different bleaching technologies, HYPER’s e-H₂O₂ achieved a whiteness degree for dyeing (Berger) higher than 70 and a full whiteness degree higher than 100 (Berger). These values match or even exceed the indicated Key Performance Indicators (KPI) for bleaching performance.
Polymerisation loss, a measure of fibre degradation, did not fall within the target (<15%), but the values observed mirror those obtained using commercial hydrogen peroxide. This suggests that optimisation of process conditions, not peroxide quality, is the controlling factor, another key insight feeding back into the process model.
Closing the Loop: How This TRL 4/5 Work Shapes the TRL 6 Demonstrator
With the TRL 4/5 stage complete, the mini-plant has been returned to project partner JSI (Slovenia) for further testing and upgrades. These planned enhancements directly reflect the learnings from process modelling and real-world operation at InoTex:
- Full automation of both electrolyser and utilizer
- Semi-continuous operation with direct anolyte transfer
- Internal recirculation of (NH₄)₂SO₄/H₂SO₄
- Improved heat and energy integration
- Process control improvements to increase hydrolysis yield
These upgrades will be implemented in preparation for the TRL 6 demonstrator, to be deployed at Belinka Perkemija in Slovenia. As models are updated with new experimental data, uncertainties shrink and system efficiency improves, strengthening the case for decentralised electrochemical H₂O₂ production.
Conclusions
The deployment of the HYPER TRL 4/5 mini-plant marks an important transition from laboratory-scale modelling to pilot-scale technical validation. Electrochemical persulphate production exceeded the project KPI, H₂O₂ yields matched expectations, and the bleaching performance of e-H₂O₂ met industry requirements for whiteness.
Together, these results confirm the feasibility of HYPER’s intermediate-persulphate process and provide high-quality data essential for refining the process model. With the mini-plant now headed for upgrades and integration into the TRL 6 demonstrator, the project moves one step closer to enabling flexible, renewable, on-site production of hydrogen peroxide, reducing transportation needs, cutting CO₂ emissions, and strengthening Europe’s chemical sustainability pathway.