Periodic Reporting for period 3 - EHLCATHOL (Chemical transformation of enzymatic hydrolysis lignin (EHL) with catalytic solvolysis to fuel commodities under mild conditions)
Reporting period: 2023-05-01 to 2024-10-31
The EHLCATHOL project, Horizon 2020 H2020-LC-SC3-2018-2019-2020 (BUILDING A LOWCARBON, CLIMATE RESILIENT FUTURE: SECURE, CLEAN AND EFFICIENT ENERGY), with a topic ”Chemical transformation of enzymatic hydrolysis lignin (EHL) with catalytic solvolysis to fuel commodities under mild conditions”, was designed based on the state-of-the-art of catalytic solvolysis of lignin and the important results of the consortium members before the proposal. Specifically, they were the first to achieve complete conversion of technical lignin to fuel range precursor molecules. However, they as well as others in follow-up works encountered typical challenges in scaling up this process, such as, recondensation of the monomers during product distillation, a relatively low lignin-to-solvent ratio in the feed, low reaction rates and yields of desired products. The key to overcome these challenges enroute to commercialization of this promising approach is to build up the needed fundamental knowledge about the underlying chemistry and process steps towards specific fuel cuts. The EHLCATHOL project is aimed to boost 2G Advanced Bioethanol Technologies, which utilizes lignocellulose, the material making up the cell wall of land-based plants, to produce fuel-grade ethanol. Bioethanol production via fermentation of non-edible lignocellulose has been demonstrated at the commercial scale at all continents in the past decade. As such, it is also expected to contribute to the EU’s 2050 carbon neutral renewable fuel goals. Nevertheless, fermentation primarily converts saccharide polymers, i.e. cellulose and hemicellulose, to fuel ethanol, leaving EHL as a waste. Therefore, the profitability of 2G bioethanol plants is hampered by the lack of efficient methods to valorise EHL, i.e. transforming the current waste by-product into more valuable products, such as fuel blends. The mid-to-long term target of the 2G bioethanol technology is to utilize forestry and agricultural residues, which contain lignin in larger amounts, roughly 35-45% in terms of energy content. It can therefore be foreseen that, as the efficiency and scale of the 2G bioethanol technology is improved, the switch of the feed to lignin-rich biomass would make EHL utilization even more demanding.
In the 4 years EHLCATHOL project, intensive and efficient collaborative research has been done within the consortium. We achieved all the goals specified in the Grant Agreement; obtained bio gasoline, bio jet-fuel samples and a promising bio-marine fuel blend with high efficiency; established knowledge on the principles of the interaction of EHL and fuel compatible solvents; and were enabled to illustrate the superiority of catalytic solvolysis in lignin valorization. We also contributed greatly to the scientific community with 28 high-quality articles, 2 special issues of an international journal and organization and presentations of/on conferences, as well as 3 webinars.
In the 4 years EHLCATHOL project, intensive and efficient collaborative research has been done within the consortium. We achieved all the goals specified in the Grant Agreement; obtained bio gasoline, bio jet-fuel samples and a promising bio-marine fuel blend with high efficiency; established knowledge on the principles of the interaction of EHL and fuel compatible solvents; and were enabled to illustrate the superiority of catalytic solvolysis in lignin valorization. We also contributed greatly to the scientific community with 28 high-quality articles, 2 special issues of an international journal and organization and presentations of/on conferences, as well as 3 webinars.
EHLCATHOL gathers the strong and expertised reserarch teams in Europe to carry out the tasks aimed at transforming waste EHL to highly demanded commodity fuels. Prof. Beller and Prof. Rajenahally from the Leibniz-Institut für Katalyse (LIKAT) investigated the key reaction mechanism of the EHL catalytic solvolysis reaction suppressing recondensation reactions of the monomeric reaction products (WP2). Prof. Chen’s team of Norges Teknisk-Naturvitenskapelige Universitet (NTNU) focused on tuning of different fuel-cuts with suitable C-C coupling, hydrogenation, alkylation and isomerization catalytic tools (WP5). Prof. Dyson of École Polytechnique Fédérale de Lausanne (EPFL) aimed to reveal, using operando spectroscopy techniques, the mechanism of the key steps of catalysed solvolysis and solvolysis oil regulation reactions, and the roles of capping agents (WP3). Aalto University (Prof. Li) and Technische Universiteit Eindhoven (Prof. Hensen) teams worked on the different aspects of catalyst development, reactor and process configurations of the EHL solvolysis process (WP1&7). Dr. Boot led the VERTORO team in bench-scale reactor tests, sample delivery, separation and scale-up (WP4). Dr. Battin-Leclerc, Director of Research of Centre National de la Recherche Scientifique (CNRS) in Nancy, and her team focused on the fuel combustion properties and the related pollutant formation of the refined EHL solvolysis products, and of the separated commodity fuels (WP6). To efficiently implement the EHLCATHOL project, WP8-11 dealt with the Exploitation, Dissemination, Communication, Project Management and Ethics issues. All projected EHLCATHOL tasks have been successfully completed within the 48-month project duration. The major outcomes of the WPs and tasks provide a solid base for achieving the project goals; the work formulated in the WPs and associated tasks were carried out efficiently reaching the specific goals.
The major scientific and technological outputs and their impacts of this EHLCATHOL project can be summarized as follows: a new catalyst formulation based on crystalline spinel CuMn-oxide was much more effective in solvolyzing EHL in ethanol than previously prepared Cu porous metal oxides. One-pot cascade reactions of EHL combining solvolysis and hydrogenation resulting in high yields of saturated alkanes were developed. Research on capping and elimination of functional groups of model compounds provided new insights into the reaction mechanism of the solvolysis and upgrading steps. Based on advanced operando NMR and FTIR, deep understanding on the reaction mechanism was obtained with the benefit of using advanced operando spectroscopy under demanding biomass conversion conditions (e.g operando NMR experiments at 150 oC). The mechanisms of guaiacol hydrogenation and associated capping reactions for too reactive functional groups was investigated, resulting in the design of new solvolysis and upgrading catalysts. Two liter-scale catalytic solvolysis setups were realized and used to supply significant quantities of solvolysis products to the EHLCATHOL partners. Combustion kinetics of EHL solvolysis and upgrading products have been established. A new kinetic model for the simulation of the combustion reaction has been proposed. New software tools for the estimation of octane and cetane numbers of neat C/H/O/N molecules were developed. The preparation of EHL- and fuel-compatible solvent slurries with extended flowable ranges were established, revealing their potential as the high-quality fuel in boiler combustion.
The possibility of lowering the reaction temperature was explored, providing large datasets on the solubility and dissolution of EHL of different sources and their solvolysis in different solvents. Reactor and molecular level kinetic models of lignin dissolution and solvolysis reaction were established. With the novel optimized mixed solvent, an EHL to solvent ratio of 1:10 was possible, which is a 10-fold advance with respect to the state of the art. The new solvent combination also facilitates downstream upgrading, making the overall process faster by spontaneous separation of the product into three distinct phases. Bio-gasoline, bio-jet-fuel and bio-marine fuel blend samples were produced. Based one of the optimized results, a techno-economic analysis shows promising simulation results for the EHL catalytic solvolysis route to produce fuel commodities on a commercial scale.
The possibility of lowering the reaction temperature was explored, providing large datasets on the solubility and dissolution of EHL of different sources and their solvolysis in different solvents. Reactor and molecular level kinetic models of lignin dissolution and solvolysis reaction were established. With the novel optimized mixed solvent, an EHL to solvent ratio of 1:10 was possible, which is a 10-fold advance with respect to the state of the art. The new solvent combination also facilitates downstream upgrading, making the overall process faster by spontaneous separation of the product into three distinct phases. Bio-gasoline, bio-jet-fuel and bio-marine fuel blend samples were produced. Based one of the optimized results, a techno-economic analysis shows promising simulation results for the EHL catalytic solvolysis route to produce fuel commodities on a commercial scale.