Periodic Reporting for period 2 - F-CUBED (Future Feedstock Flexible Carbon Upgrading to Bio Energy Dispatchable carriers)
Reporting period: 2021-11-01 to 2023-10-31
Europe aims to reduce greenhouse gas emissions by at least 55% compared to 1990 levels by 2030, and bioenergy from residue streams can play a substantial role in reaching this goal. Wet residue streams are a particular challenge: in addition to having low energy density they often require additional processing for safe disposal. Biological sludges and food waste residues total 21 and 99 Mt annually in Europe, representing a significant bioenergy potential. However, these residue streams are often landfilled, incinerated or applied to agricultural land, resulting in economic and environmental challenges.
The goal of F-CUBED is to unlock the bioenergy potential of low quality residues by hydrothermally converting a range of wet biogenic residues into intermediate bioenergy carriers (fuel pellets) with superior energy density and durability, thus providing flexibility to the energy system.
The target residue streams in F-CUBED are: biological paper sludge, olive pomace and orange peels. The F-CUBED process consists of a mild hydrothermal treatment (TORWASH) that converts the residues into dewaterable solids (pellet production) and a digestible liquid effluent (biogas production). The F-CUBED process is also optimized to facilitate the recovery of added-value products, including nutrients (N, P, K) and oils (olive oil, terpenes). Thus, the F-CUBED process turns the environmental and economic challenges of wet biogenic residue streams into an opportunity.
The main conclusions of the project are that the proposed F-CUBED process is a promising option for the treatment of the target wet residue streams. On a techno-economic level, the F-CUBED process is more energy efficient than current methods for processing these residue streams. On an environmental level, the F-CUBED process is significantly better than current practices with respect to CO2 emissions released during the process, even resulting in negative emissions for olive pomace and orange peels. The F-CUBED project demonstrates the potential of hydrothermal treatment of wet residue streams by proving the concept at continuous, pilot scale on-location at industrial sites. This is an important step in scaling up the process across a wide range of feedstocks and industries.
The goal of F-CUBED is to unlock the bioenergy potential of low quality residues by hydrothermally converting a range of wet biogenic residues into intermediate bioenergy carriers (fuel pellets) with superior energy density and durability, thus providing flexibility to the energy system.
The target residue streams in F-CUBED are: biological paper sludge, olive pomace and orange peels. The F-CUBED process consists of a mild hydrothermal treatment (TORWASH) that converts the residues into dewaterable solids (pellet production) and a digestible liquid effluent (biogas production). The F-CUBED process is also optimized to facilitate the recovery of added-value products, including nutrients (N, P, K) and oils (olive oil, terpenes). Thus, the F-CUBED process turns the environmental and economic challenges of wet biogenic residue streams into an opportunity.
The main conclusions of the project are that the proposed F-CUBED process is a promising option for the treatment of the target wet residue streams. On a techno-economic level, the F-CUBED process is more energy efficient than current methods for processing these residue streams. On an environmental level, the F-CUBED process is significantly better than current practices with respect to CO2 emissions released during the process, even resulting in negative emissions for olive pomace and orange peels. The F-CUBED project demonstrates the potential of hydrothermal treatment of wet residue streams by proving the concept at continuous, pilot scale on-location at industrial sites. This is an important step in scaling up the process across a wide range of feedstocks and industries.
Treatment conditions of the target feedstocks (paper sludge, olive pomace, orange peels) were optimized at lab and pilot scale. Continuous, long-duration pilot testing was conducted on-location where the residues were generated. The hydrothermally-treated residues were dewatered at pilot-scale on site using a mechanical filter press. The solids were dried and pelletized and the liquid fraction was tested for biogas production potential via anaerobic digestion. The pellets were characterized and compared to wood pellets and industrial pellets. Pellets produced in F-CUBED were pyrolyzed to produce a char and syngas.
Extensive modeling was performed based on the results of the lab- and pilot-scale tests, to develop a process model, reactor model, value chain model and to evaluate the techno-economic, environmental and social performance of the F-CUBED process.
Results show that the F-CUBED process is successful for treating the target residue streams, resulting in an energy yield > 50%, volume reduction > 83 %, and moisture removal Pellet quality for orange peel and olive pomace meets requirements for industrial-use pellets. Pellets produced from paper sludge were of lower quality, but were suitable for use in paper mills for heat generation. Pellets could be pyrolyzed consistently and resulted in good char conversion and syngas production (in particular olive pomace, although residual oil resulted in a less durable pellet).
The F-CUBED process demonstrated parallel recovery of oils (terpenes and olive oil). Nutrients (N, P) could be most successfully recovered from paper sludge processing. Solids from paper sludge processing could also be used as a partial coal replacement (4%) in briquette making for metallurgical applications.
The environmental performance of the F-CUBED process was excellent, demonstrating greenhouse gas emissions savings of 93%, 274% and 476% for paper sludge, olive pomace and orange peels, respectively, when compared to a reference case process for electricity generation from the residues. From a techno-economic and value chain perspective, the F-CUBED process is more energy efficient than reference processes. The best financial case is for the treatment of paper sludge. Value chain modeling further demonstrated additional cost savings via processing hubs.
Several dissemination activities were conducted to increase the visibility of the project for both the scientific and industrial communities. This includes 12 videos about the project (plus 10+ videos from the final conference), and over 30 articles and publications (peer-reviewed and industry-focused). Additional scientific publications will be published after the end of the project. Through the results and dissemination activities, the potential of the F-CUBED project and process has been showcased.
Extensive modeling was performed based on the results of the lab- and pilot-scale tests, to develop a process model, reactor model, value chain model and to evaluate the techno-economic, environmental and social performance of the F-CUBED process.
Results show that the F-CUBED process is successful for treating the target residue streams, resulting in an energy yield > 50%, volume reduction > 83 %, and moisture removal Pellet quality for orange peel and olive pomace meets requirements for industrial-use pellets. Pellets produced from paper sludge were of lower quality, but were suitable for use in paper mills for heat generation. Pellets could be pyrolyzed consistently and resulted in good char conversion and syngas production (in particular olive pomace, although residual oil resulted in a less durable pellet).
The F-CUBED process demonstrated parallel recovery of oils (terpenes and olive oil). Nutrients (N, P) could be most successfully recovered from paper sludge processing. Solids from paper sludge processing could also be used as a partial coal replacement (4%) in briquette making for metallurgical applications.
The environmental performance of the F-CUBED process was excellent, demonstrating greenhouse gas emissions savings of 93%, 274% and 476% for paper sludge, olive pomace and orange peels, respectively, when compared to a reference case process for electricity generation from the residues. From a techno-economic and value chain perspective, the F-CUBED process is more energy efficient than reference processes. The best financial case is for the treatment of paper sludge. Value chain modeling further demonstrated additional cost savings via processing hubs.
Several dissemination activities were conducted to increase the visibility of the project for both the scientific and industrial communities. This includes 12 videos about the project (plus 10+ videos from the final conference), and over 30 articles and publications (peer-reviewed and industry-focused). Additional scientific publications will be published after the end of the project. Through the results and dissemination activities, the potential of the F-CUBED project and process has been showcased.
F-CUBED validated a hydrothermal treatment process (Torwash) for the conversion of wet biogenic residues into intermediate bioenergy carriers, scaling up the technology from TRL3 to TRL5. The F-CUBED process is feedstock flexible, which is a key innovative feature. The technology can treat a wide variety of wet residues with minimal process adjustments. This makes F-CUBED particularly interesting for industries or geographical regions with a variety of wet residue streams that are unevenly distributed and/or seasonal in nature. This has been demonstrated in the project with the successful treatment of biological paper sludge, olive pomace and orange peels residue streams.
In addition, F-CUBED demonstrated the co-recovery of added-value products during the process. This includes nutrients (namely N and P), secondary olive oil and terpenes. This improves the overall circularity of the F-CUBED process.
F-CUBED progress beyond the state of the art upgraded wet biogenic residues into solid bioenergy carriers with an energy density of at least 5.5 GJ/m3. This was achieved: the produced solid pellets had energy densities of 14, 16 and 13 GJ/m3 for paper sludge, olive pomace and orange peels, respectively. The GHG emissions savings calculated for the bio-pellets production, when compared to fossil fuel (i.e. 183 g CO2eq/MJ electricity) are 49%, 89% and 91%, for Pulp & Paper Bio-Sludge, Olive Pomace, and Orange Peels, respectively.
The best financial case for the F-CUBED process is for paper sludge. The economics of seasonal feedstocks like olive pomace and orange peels can be improved by increasing operating hours (i.e. developing a system that treats multiple feedstocks throughout the year).
The F-CUBED project has demonstrated the potential of hydrothermal treatment for upgrading wet biogenic residue streams. The continuous, pilot-scale processing of these residues on-location at industrial sites represents an important step in scaling-up this type of technology in the future, ultimately leading to more sustainable and resource efficient industry.
In addition, F-CUBED demonstrated the co-recovery of added-value products during the process. This includes nutrients (namely N and P), secondary olive oil and terpenes. This improves the overall circularity of the F-CUBED process.
F-CUBED progress beyond the state of the art upgraded wet biogenic residues into solid bioenergy carriers with an energy density of at least 5.5 GJ/m3. This was achieved: the produced solid pellets had energy densities of 14, 16 and 13 GJ/m3 for paper sludge, olive pomace and orange peels, respectively. The GHG emissions savings calculated for the bio-pellets production, when compared to fossil fuel (i.e. 183 g CO2eq/MJ electricity) are 49%, 89% and 91%, for Pulp & Paper Bio-Sludge, Olive Pomace, and Orange Peels, respectively.
The best financial case for the F-CUBED process is for paper sludge. The economics of seasonal feedstocks like olive pomace and orange peels can be improved by increasing operating hours (i.e. developing a system that treats multiple feedstocks throughout the year).
The F-CUBED project has demonstrated the potential of hydrothermal treatment for upgrading wet biogenic residue streams. The continuous, pilot-scale processing of these residues on-location at industrial sites represents an important step in scaling-up this type of technology in the future, ultimately leading to more sustainable and resource efficient industry.