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New Scientific Publication: A Roadmap for Decarbonizing Industrial Drying

As part of their leading role in Work Package 10,  the Environmental and Techno-Economic Assessment of Superheated Steam Drying — researchers from the University of Santiago de Compostela (USC) have just published a peer-reviewed study that lays the scientific groundwork for evaluating the sustainability of industrial drying technologies. USC’s Group of Environmental Biotechnology (Biogroup) is coordinating this critical workstream within SteamDry, and this publication is a direct output of that work.

The article is out now, fully open access, in the journal Environmental Technology & Innovation:

“Toward the decarbonization of industrial drying technologies: Cross-sector sustainability, economics and efficiency integrated assessments with emphasis on the wood and paper industries”
José Luis Ares-Sainz, Ana Arias, Gumersindo Feijoo & María Teresa Moreira
Environmental Technology & Innovation, 2026 .

Why Drying Matters for Industrial Decarbonization

Industrial drying is often an invisible process — yet it is one of the most energy-hungry operations in manufacturing. In the wood industry, the drying stage alone consumes 50–70% of the total process energy. In paper production, that figure rises to 60–80%. At the European level, 91% of the energy used for industrial heating and cooling still comes from fossil fuels, making drying a critical pressure point in the path toward net-zero emissions by 2050.

This is precisely the challenge that the SteamDry project was designed to address. And this new publication is a cornerstone contribution to that mission.

What the Paper Does

This critical review, conducted in accordance with PRISMA guidelines, systematically analysed 59 scientific articles published between 2004 and April 2025, covering drying technologies used in the wood and paper industries. The study evaluated each technology across three dimensions:

  • Energy performance, using Specific Energy Consumption (SEC, in MJ per kg of evaporated water) and energy efficiency as standardised benchmarks.
  • Environmental sustainability, through the lens of Life Cycle Assessment (LCA) methodology.
  • Economic viability, via Techno-Economic Analysis (TEA).

The result is one of the most comprehensive cross-sector assessments of industrial drying published to date.

Key Findings

The Wood Industry: Significant Potential for Improvement

Conventional kiln dryers — the industry standard — show an average SEC of 3.80 MJ/kg of evaporated water. But more efficient alternatives are already available:

  • Heat-pump-assisted kilns reduce SEC to an average of 2.39 MJ/kg, a 37% improvement.
  • Hybrid solar dryers with heat pumps can push SEC as low as 0.75 MJ/kg — the most sustainable option identified for wood drying.
  • High-temperature kilns and optimised air velocity strategies have shown reductions of 35–59% in energy consumption compared to conventional systems.
  • Superheated steam drying achieves SEC values of 0.7–1.0 MJ/kg, though it remains underexplored at industrial scale.
The Paper Industry: Optimisation Over Transformation

In paper manufacturing, research has focused more on refining existing technologies than introducing radically new ones:

  • Multi-cylinder dryers (85–90% of the industry) show an average SEC of ~3.3 MJ/kg and efficiency close to 75%.
  • Yankee dryers (used mainly for tissue paper) present higher consumption, around 4.7 MJ/kg.
  • Infrared dryers are the least efficient, with averages around 6.5 MJ/kg.
  • Emerging solutions like heat pumps and superheated steam could reduce paper drying energy use by 17–34%, respectively.
A Clear Gap in Sustainability Assessment

Despite broad consensus on the need to decarbonise drying, the systematic review reveals a striking gap in the use of standardised assessment tools:

  • Only 10 out of 59 articles applied full LCA methodology (ISO 14040–14044).
  • Only 11 out of 59 articles applied any form of Techno-Economic Analysis.
  • Just 1 study applied LCA exclusively to the drying stage itself.
  • A total of 32 different environmental indicators were used across studies — making comparison across technologies extremely difficult.

This lack of harmonisation is a key barrier to informed decision-making and to demonstrating the real benefits of new drying technologies to industry and policymakers.

Environmental Impact: What We Know So Far

Despite limited data, available LCA evidence paints a clear picture of how much drying matters for a product’s environmental footprint:

  • Kiln drying increases the global warming impact of redwood lumber by ~34 kg CO₂ eq/m³ compared to equivalent green (undried) products.
  • In oriented strand board (OSB) production, the drying stage contributes 25–27% of the total climate change impact.
  • In the paper sector, switching from a natural gas boiler to a high-temperature heat pump for steam generation can reduce greenhouse gas emissions by ~40% under the European electricity mix.
  • Solar-assisted wood drying systems can avoid between 26 and 66 tonnes of CO₂ per year depending on the configuration and climate.

The Road Ahead

The paper calls for a more coordinated research agenda across the sector. Specifically, it recommends:

  1. Standardising SEC and energy efficiency definitions across studies to enable meaningful comparisons.
  2. Integrating LCA and TEA from the outset of technology development, not as an afterthought.
  3. Scaling up evaluation of emerging technologies — heat pumps, solar-assisted dryers, and superheated steam systems — from pilot projects to industrial demonstrations.
  4. Expanding environmental assessments beyond carbon footprint to include impacts such as particulate matter, land use, and resource depletion, particularly as low-carbon alternatives are adopted.

Relevance for SteamDry

This publication provides the scientific foundation that directly informs the SteamDry project’s work. Superheated steam drying — the core technology of our project — emerges from this review as one of the most promising pathways for decarbonising industrial drying, with SEC values up to five times lower than conventional kiln drying. Yet, as the paper confirms, it remains underrepresented in the scientific literature, especially at industrial scale.

SteamDry is here to change that. This review maps exactly where the knowledge gaps are — and where our project is uniquely positioned to fill them.

Access the Full Paper

The article is published as open access and is freely available to all readers:

📄 Read the full paper: https://zenodo.org/records/21786324

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New Filtration Model by SteamDry Partners Boosts Superheated Steam Drying

A new open‑access paper from partners in the SteamDry project presents a dynamic model for filtration of dusty superheated steam, directly supporting the move toward more energy‑efficient paper drying. The study focuses on how dust fouling develops in a dead‑end filter and how this fouling increases pressure drop over time in a closed‑loop superheated steam drying (SSD) system.

The work, titled “Dynamic modeling of fouling development during dead‑end filtration of dusty superheated steam,” was published in Systems & Control Transactions and presented at ESCAPE 36 in Sheffield in June 2026. It offers a compact, physics‑based model that can be used for parameter identification, prediction, and eventually optimization and control of SteamDry lines.

Who Is Behind the Study?

The paper is authored by Felipe de Oliveira, Wijtze Nijhuis, and Edwin Zondervan from the University of Twente (Department of Chemical Engineering), together with Marcel Meinders from Wageningen University & Research (Department of Food Technology).

Within the SteamDry project, these groups play complementary roles:

  • The University of Twente team leads process modeling, dynamic simulation, and control concepts for superheated steam drying and related unit operations. Their work focuses on creating models that are simple enough for plant‑wide use, but rich enough to capture key physics such as fouling dynamics and pressure‑drop behavior.
  • The Wageningen University & Research team contributes deep expertise in food and biomass processing, particle behavior, and experimental methods, helping to design realistic test conditions and interpret fouling phenomena in terms of cake structure and dust properties.

Together, they provide the modeling and experimental backbone that SteamDry needs to develop robust, validated digital tools for SSD design and operation.

What the Filtration Model Does

The authors develop a “parsimonious” dynamic model for dead‑end filtration of dusty superheated steam containing paper‑like dust. The model is built on Darcy’s law and represents the total resistance as the sum of two parts:

  • A constant intrinsic filter resistance.
  • A time‑dependent cake resistance that grows as dust accumulates on the filter surface.

Cake thickness is linked directly to the deposited dust mass, effective filter area, and cake density, so that, over time, higher dust loading translates into higher pressure drop. Key parameters, such as filter resistance and specific cake resistance, are obtained from experiments, while gas properties are calculated using thermophysical correlations.

From Experiments to Predictive Power

To calibrate and validate the model, the team built a dedicated superheated steam filtration setup. Dust‑laden steam is produced, routed through a PTFE filter mounted in an oven, and monitored for temperature and pressure drop; total deposited mass is determined by weighing the filter before and after each run.

When the dust dosing rate is assumed to be constant, the model captures the overall trend in pressure drop but shows only limited agreement with experimental data in the dust filtration stage (R² ≈ 0.24). By inverting the problem and estimating the time‑varying dust load that best matches the measured pressure drop, the authors improve the fit dramatically to R² ≈ 0.94, revealing how strongly pressure‑drop predictions depend on realistic solid‑loading profiles.

Why This Matters for the SteamDry Project

For SteamDry, this dynamic filtration model is an important step toward fully model‑based design and operation of superheated steam drying systems for paper and board. It can be:

  • Extended to a wider range of temperatures, flows, and dust levels, with statistical analysis of fitted parameters to capture variability.
  • Coupled with filter‑cleaning models to simulate long‑term cyclic operation and evaluate cleaning strategies.
  • Integrated into dynamic optimization and control frameworks that keep pressure drop, energy use, and cleanliness in balance under realistic disturbances.
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USC and Steamdry push Parametric LCA forward with new open access article

Parametric Life Cycle Assessment (Pa‑LCA) is becoming a key tool for designing the low‑carbon, resource‑efficient technologies we need for the green and digital transition. But until now, there has been no clear, shared roadmap on how to actually do Pa‑LCA in a robust, comparable way.

Researchers from the Universidade de Santiago de Compostela (USC) and their co‑authors have just published a new open‑access review article, “Advancing parametric life cycle assessment (Pa‑LCA): A systematic review and methodological roadmap for enhanced sustainability assessments.” This work looks at 95 Pa‑LCA studies from the last decade and distils them into a practical framework that helps researchers and practitioners design better parametric LCAs, from choosing parameters and KPIs to handling sensitivity and uncertainty.

For Steamdry, USC is a key partner leading the methodological and assessment work. Their role in the project is to develop and apply advanced LCA and Pa‑LCA methods, define key performance indicators, and make sure that the technologies developed in Steamdry are evaluated with the best available science. This new paper is a tangible example of USC’s contribution to Steamdry: it provides the scientific backbone we will use to build dynamic, transparent, and decision‑ready sustainability assessments throughout the project.

Read here the full article.