The project will investigate the potential opportunities and/or technical limitations related to the use of the technology of torrefaction of logging residue and/or post-disaster timber and subsequent conversion of the torrefied product to solid fuels (pelletisation/briquetting). The purpose of the production and utilisation of such biomass fuels is to conserve fossil fuels and reduce their negative environmental impact.

The specific objectives of the project are as follows:

1. To identify the available base of raw materials for torrefaction and subsequent pelletisation/briquetting of the torrefied product;
2. To determine the mean quality parameters of the input products for torrefaction and identify the factors that affect these parameters, as well as to assess the compliance of the quality characteristics of products for torrefaction with the technical requirements imposed by the current power generating equipment (and suggest the solutions to potential discrepancies);
3. To determine the critical parameters of the torrefaction process and the quality parameters of the torrefied product;
4. To determine the parameters of the densification process of the torrefied product, and indicate the optimal technical design parameters of the densification equipment in order to obtain high-quality end products (pellets/briquettes).

The literature review indicates that torrefaction of plant material of forest origin has been tested exclusively for selected types of fuel wood other than specified in our project, whereas there is only incomplete data regarding the potential torrefaction of wood waste, particularly residues from clear-cutting/thinning sites and post-disaster areas. Logging residues are a by-product of wood harvesting and their composition differs substantially from that of typical wood. They contain a substantial proportion of bark, needles, litter, mineral impurities, etc. Post-disaster timber, which comes mainly from windsnap/windthrow and wood infested by secondary pests, typically does not meet quality standards. Importantly, logging residues and post-disaster wood need to be properly managed, as they should not be left entirely on logging sites.

There are no studies describing the torrefaction of forest logging residues or the agglomeration of the resulting torrefied product. It also remains unknown whether pellet machines available in the market could be used for this type of material, or perhaps some modifications in their design would be required.

The intended research project is to address the following issues:

1. What are the current raw materials base and its future forecasts?
2. What will be the energy characteristics of the torrefied product from logging residues of heterogeneous composition or post-disaster wood; and
3. Is the densification of the resulting torrefied product possible and what energy, physical and mechanical characteristics of the agglomerate can be achieved.

The input material will be residues from logging sites and post-disaster substandard wood.

The project will be divided into two stages.

In the stage one, research will involve the identification of the availability of forest material for torrefaction, accounting for the legal regulations regarding the use of logging residues, as well as the analysis of the quality parameters of products before and after torrefaction. Based on measurements, it will be possible to compare the properties of fuels and identify the conditions that maximise the energy recovery from torrefied products obtained from wood raw materials. These parameters are crucial in terms of fitness of the particular material for energy purposes, and affect all thermotechnical calculations (stoichiometry).

The fuel characteristics of torrefied products will be then compared with both the quality requirements for coal, lignite and other products. The relevant analyses of waste wood will be conducted using specialised laboratory equipment owned by the centres involved in the project (from Czechia, Hungary, Poland, Slovakia).

In the stage two, the torrefied product will be subjected to pressure agglomeration at a laboratory station (densification head mounted on a universal testing machine), which provides for maintaining constant process parameters (temperature, chamber dimensions, compression speed, etc.) and recording of results. The produced pellets/briquettes will be tested for compactibility and physical parameters. The tests will be conducted in compliance with the applicable standards and research procedures.

Project innovativeness and added value

Innovativeness

1. The novelty of research lies in the investigation of a material from forest logging sites and post-disaster areas, the composition and characteristics of which differ substantially from pure timber or other plant waste.
2. The novelty of research is the torrefaction of logging residues/post-disaster timber and the identification of the energy properties of the torrefied product.
3. The novelty of research is the pressure agglomeration of the torrefied product obtained from forest logging residues/post-disaster timber.
4. Another novelty is the identification of the physical and mechanical properties (density, relaxation, mechanical durability, etc.) of the agglomerate obtained from the torrefied logging residues/post-disaster timber.

Main added value

1. The project will contribute to the identification of the available amount of forest biomass in the form of logging residues and post-disaster wood for energy purposes;
2. The project will contribute to increasing knowledge about the development and use of solid fuels from renewable energy sources;
3. The project will contribute to solving the existing problems of the power industry, where electricity and heat generation is based mainly on coal, through the substitution of non-renewable coal products by solid fuels from renewable energy sources;
4. The project may contribute to the development of machines for pressure agglomeration and production of rectified fuels.

Power generation in V4 countries is based mainly on coal. While the EU requirements impose a gradual reduction in the use of coal and search for alternative energy sources, forest biomass may become a major supplement in the aggregate renewable energy mix.

Research needs to focus on innovations leading to low-carbon, efficient and flexible use of materials, such as torrefaction or gasification. And the compaction process ensures homogenisation of structure and size of biofuels dedicated to the use in combustion systems and automation of fuel feeding to a combustion chamber.

For social, economic and environmental purposes, coal regions in V4 will undergo restructuring. Biomass products obtained from logging residues and as a result of increasingly frequent forest disasters will likely gain in importance. Torrefaction and pressure agglomeration of logging residues and post-disaster wood may increase the use of renewable energy sources in V4 countries. Determining the optimal parameters of the process of production of fuel from torrefied biomass may influence the development or modification of the relevant machinery, which will stimulate the production companies and the entire economy.

Agglomeration increases the specific density of biofuels (radically reducing the transport and storage costs) as well as their energy density.

The fuel addressed in the project, obtained by processing of forest logging residues and post-disaster wood, will also contribute to the achievement of objectives for renewable energy sources and have a positive impact on the environment in V4 countries.

APPLICANT / PROJECT LEADER

Warsaw University of Life Sciences (WULS), Institute of Mechanical Engineering

• Dr hab. inż. Arkadiusz Gendek, prof. SGGW
• Dr hab. inż. Monika Aniszewska, prof. SGGW

PROJECT PARTNERS

Czech University of Life Sciences Prague, Faculty of Technology, Czech Republic;

• Prof. Jan Malaťák PhD
• Jiří Bradna, PhD

Technical University in Zvolen, Faculty of Technology, Slovakia;

• Prof. Jozef Krilek PhD
• Iveta Čabalová PhD

University of Agriculture in Krakow, Faculty of Forestry, Poland;

• Dr hab. inż. Grzegorz Szewczyk, prof. UR
• Dr hab. inż. Paweł Tylek, prof. UR

Faculty of Forestry, Institute of Forest and Natural Resource Management, Sopron University, Hungary;

• Katalin Mária Mátyás, PhD

Working meeting of the research team in Poland, Krakow, PL

Date: 03/02/2025—06/02/2025

The workshops are scheduled to last 4 days plus two days for travel. Each V4 country (PL, CZ, SK 2 people each, HU 1 person) will send people involved in the project to work on the described details (PL, CZ, SK 2 people each, HU 1 person). During the workshops, we plan office, field and laboratory days. The office day will be devoted to a literature review. This will allow you to establish and understand the context of the problem and help you better prepare for the field trip. The results of the literature review will be incorporated into the guidelines. During the field day, we will visit biomass processing plants, manufacturers of biomass pressure agglomeration equipment and forest areas from which research material will be obtained. Activities aimed at promoting the project will also be included.

Working meeting of the research team in Czech Republic, Prague, CZ

Date: 30/06/2025–03/07/2025

Research conduct, laboratory work, publication development, report development, conference preparations The workshops will last 5 days plus two days for travel. Each V4 country (PL, CZ, SK 2 people each, HU 1 person) will send people involved in the project to work on the described details (PL, CZ, SK 2 people each, HU 1 person). During the workshops, we plan office, field and laboratory days. The office day will be devoted to a literature review. The results of the literature review will be incorporated into the guidelines. During the meeting days, the implementation of the project and further actions that need to be taken for its implementation will be discussed. During the field day, we will visit biomass processing plants, manufacturers of devices for pressure agglomeration of biomass, and forest areas from which research material will be obtained. Activities aimed at promoting the project will also be included.

Conference in Poland, Zakopane, PL

14/01/2026–16/01/2026

A three-day scientific conference to summarise and disseminate the project outcome. The conference will facilitate the exchange of perspectives between researchers and practitioners and enable the launch of activities aimed to introduce the new types of solid fuels from torrefied forest biomass into practical use. The conference is planned in a hybrid, free form, which will ensure a wide range of potential participants. The conference will take place in a forest center in Zakopane, where international scientific conferences organized by Polish scientific units participating in the project are held periodically.

Working meeting of the research team in Slovakia, Zvolen, SK

Date: 02/02/2026–05/02/2026

Research conduct, laboratory work, publication development, report development. Like the previous workshops, this one is also scheduled for 5 working days + two days for travel. The main goal will be to carry out work related to the summary of the conference and the completion of the project. The workshops will consist of office and field days. Office days will focus on preparing final reports, monographs from conference materials, preparing a scientific publication, and preparing a final report. If necessary, laboratory work will also be carried out. Field days will include meetings with local companies, the forest community and organizations promoting fuels from renewable sources.