Catalytic Hydrotreatment of Kraft Lignin to Aromatics

Project Information

Lig2BTX

Grant agreement ID: 101064555

DOI

10.3030/101064555

Project terminated on 11 July 2025

EC signature date 12 August 2022

Start date 1 November 2023

End date 31 July 2025

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 155 548,26

Coordinated by

UNIVERSITAET GRAZ
Austria

Periodic Reporting for period 1 - Lig2BTX (Catalytic Hydrotreatment of Kraft Lignin to Aromatics)

Reporting period: 2023-11-01 to 2025-07-31

Summary of the context and overall objectives of the project

The European Green Deal has set itself the goal of making Europe climate-neutral by 2050. To achieve this, it is essential to replace fossil raw materials with renewable resources for fuels, energy and chemicals. Aromatic hydrocarbons such as benzene, toluene and xylene (BTX) are essential for the production of plastics, fibres, pharmaceuticals, detergents and dyes. At present, almost the entire BTX supply is dependent on crude oil. The development of sustainable alternatives is therefore a strategic priority for Europe’s energy independence, environmental goals and industrial competitiveness.

Lignin, a natural polymer found in plants, is the only renewable raw material rich in aromatic rings. It is produced in very large quantities as a by-product of the pulp and paper industry by around 130 million tonnes per year worldwide, but is mostly burned to produce low-value energy. Exploiting the potential of lignin for the production of BTX could make it a cornerstone of the circular bioeconomy.

The Lig2BTX project has addressed this challenge by developing a solvent-free catalytic hydrotreatment process to convert Kraft lignin into valuable aromatics. Within the project, novel “dandelion-type” hollow microsphere catalysts based on non-noble metals (Ni, Co, Mo, W, Y) were developed to achieve an efficient, selective and sustainable conversion of lignin. By integrating catalyst synthesis, reactor engineering, and knowledge at the molecular level, the project aimed to develop a scalable process that reduces costs, increases selectivity towards aromatics and contributes to a profitable biorefinery model.

The expected impacts include the following:

1. Scientific: Increased knowledge of catalytic lignin utilisation through breakthrough catalyst designs and process innovations.

2. Industrial: Providing new pathways for biorefineries to diversify products and reduce dependence on petroleum-derived aromatics.

3. Societal: Supporting the European climate targets, the UN Sustainable Development Goals and the transition to a circular economy.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

In the course of the grant, a wide range of catalysts were successfully synthesised and tested as part of the project and detailed studies on lignin conversion processes were carried out:

1. Development of catalysts: ten hollow dandelion-type hollow microsphere catalysts were synthesised, including Ni/Co/Y-promoted Mo/W systems and bimetallic NiCu and NiZn catalysts. These catalysts showed good reproducibility, high surface area and promising activity.

2. Catalytic evaluation: Due to delays in the delivery of the reactor, the catalytic tests were carried out in batch systems instead of semi-continuous systems. Nevertheless, significant results were achieved. NiCu catalysts showed excellent selectivity (up to 99%) for cyclohexanol in the hydrodeoxygenation of guaiacol. NiMo and NiYMo catalysts produced oxygen-free aromatics (up to 27%) and alkylphenols (30%) from Kraft lignin.

3. Reactor and process studies: Parameters such as temperature, hydrogen pressure and catalyst loading were systematically investigated to understand product selectivity and molecular adsorption behaviour. Guaiacol and phenol were used as model compounds to identify the reaction pathways relevant for lignin conversion.

4. Interdisciplinary and collaborative research: Collaboration with leading European groups enabled advanced analyses (e.g. 2D-GC, SP-ICP-MS, NMR) and access to industrial lignin feedstocks, broadening the scientific impact.

5. Dissemination and training: A review article was published in ACS Energy & Fuels. Another research article is accepted on 16 September 2025 in Chemical Engineering Journal Advances and further manuscripts are in preparation for Green Chemistry, ACS Sustainable Chemistry & Engineering and Fuel. Results have been presented at international conferences including Gordon Research Conferences, Chemietage 2024 and ICGSC2025 etc.

6. Despite the limited equipment, most of the scientific objectives of the project were achieved, the researcher was trained in catalyst synthesis, process optimisation and interdisciplinary utilisation of biomass and the basis for follow-up projects was created.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The Lig2BTX project has made several advances that go beyond the state of the art in lignin utilisation: 1. the development of novel catalysts: it has been demonstrated that unsupported, hollow-structured bimetallic catalysts (NiCu, NiMo, NiYMo) are highly effective for lignin hydrotreatment and guaiacol hydrodeoxygenation and outperform conventional systems.

2. Breakthroughs in selectivity: Achieved high selectivity (99%) of cyclohexanol from guaiacol and significant yields of oxygen-free aromatics from Kraft lignin under solvent-free conditions, an important step towards replacing BTX from fossil feedstocks.

3. Molecular insights: Clarification of the adsorption and reaction behaviour of lignin model compounds, providing guidance for rational catalyst design.

4. Scalability potential: Demonstrated that hydrothermal synthesis of dandelion-type catalysts can be scaled up, supporting industrial relevance.

The project contributes to Europe’s strategic autonomy in raw materials by opening the door to bio-based aromatics production. The following steps are required for further dissemination and success:

1. Transition from batch to continuous reactors to demonstrate industrial feasibility.

2. Techno-economic and life cycle assessments to validate cost competitiveness and sustainability.

3. Increased collaboration with industrial partners to bridge the gap from lab to pilot scale.

4. Supportive regulatory and policy frameworks for bio-based aromatics to accelerate market entry.

Overall, Lig2BTX strengthens Europe’s position as a leader in sustainable catalysis and biorefining, while laying the scientific and technological foundation for a future in which lignin is transformed from a low-value by-product into a renewable resource for key chemicals.

Review article was highlighted as front cover picture of Energy & Fuel journal with Vol. 39/Issue 6