| 1. |
- Nickel, David, 1990, et al.
(författare)
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Multi-Scale Variability Analysis of Wheat Straw-Based Ethanol Biorefineries Identifies Bioprocess Designs Robust Against Process Input Variations
- 2020
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Ingår i: Frontiers in Energy Research. - : Frontiers Media SA. - 2296-598X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Bioprocesses based on (ligno-)cellulosic biomass are highly prone to batch-to-batch variations. Varying raw material compositions and enzyme activities hamper the prediction of process yields, economic feasibility and environmental impacts. Commonly, these performance indicators are averaged over several experiments to select suitable process designs. The variabilities in performance indicators resulting from variable process inputs are often neglected, causing a risk for faulty performance predictions and poor process design choices during scale-up. In this paper, a multi-scale variability analysis framework is presented that quantifies the effects of process input variations on performance indicators. Using the framework, a kinetic model describing simultaneous saccharification and ethanol fermentation was integrated with a flowsheet process model, techno-economic analysis and life cycle assessment in order to evaluate a wheat straw-based ethanol biorefinery. Hydrolytic activities reported in the literature for the enzyme cocktail Cellic® CTec2, ranging from 62 to 266 FPU·mL−1, were used as inputs to the multi-scale model to compare the variability in performance indicators under batch and multi-feed operation for simultaneous saccharification and fermentation. Bioprocess simulations were stopped at ethanol productivities ≤0.1 g·L−1·h−1. The resulting spreads in process times, hydrolysis yields, and fermentation yields were incorporated into flowsheet, techno-economic and life cycle scales. At median enzymatic activities the payback time was 7%, equal to 0.6 years, shorter under multi-feed conditions. All other performance indicators showed insignificant differences. However, batch operation is simpler to control and well-established in industry. Thus, an analysis at median conditions might favor batch conditions despite the disadvantage in payback time. Contrary to median conditions, analyzing the input variability favored multi-feed operation due to a lower variability in all performance indicators. Variabilities in performance indicators were at least 50% lower under multi-feed operation. Counteracting the variability in enzymatic activities by adjusting the amount of added enzyme instead resulted in higher uncertainties in environmental impacts. The results show that the robustness of performance indicators against input variations must be considered during process development. Based on the multi-scale variability analysis process designs can be selected which deliver more precise performance indicators at multiple system levels.
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| 2. |
- Helander, Harald, 1991, et al.
(författare)
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What do product-level circular economy indicators measure?
- 2021
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Ingår i: 4th Conference on Product Lifetimes and the Environment (PLATE) proceedings.
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Konferensbidrag (refereegranskat)abstract
- Recently, the concept of circular economy (CE) has become more popular amongst researchers and practitioners as a solution to current unsustainable production and consumption practices. Several indicators meant to quantitatively assess the CE have been suggested in both the academic and grey literature. For companies, indicators are crucial for monitoring progress and to support decision making towards improved circularity. However, no consensus regarding the definition of the CE exists and as a result there is a significant divergence of what CE indicators in fact measure. Taking a product-system perspective and focusing on resources, we review existing CE indicators at the product-level and map the physical resource flows they quantify over the life cycle on a novel, generic system model in the form of a flowchart. The analysis highlights the difference between the indicators and shows that most only address parts of the life cycle with a focus on recycling-related flows. Existing gaps identified primarily relate to the use phase, e.g. lifetime extension measures like repair, maintenance, or repurposing, but also include other relevant aspects in the use phase like energy auxiliaries. The constructed flowcharts can guide the future development of indicators or point to ways of combining several indicators to capture larger parts of the product system.
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| 3. |
- Hermansson, Frida, 1988, et al.
(författare)
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A procedure for Prospective LCA in Materials Development - The Case of Carbon Fibre Composites
- 2023
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Ingår i: Abstracts book (SETAC Europe Annual Meeting). - 2309-8031 .- 2310-3043. ; 33 RD ANNUAL MEETING, s. 740-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- 1. Introduction Life cycle assessment is a powerful tool for quantifying the environmental impacts of products and services and is an essential part of product development. It can, for example, be used to identify hotspots to find ways to keep environmental impacts as small as possible. Assessing a product or service under development requires a prospective approach. A problem in prospective life cycle assessment (pLCA) is, however, the lack of data, which can lead to inconclusive results. The prospective context, however, also implies that there is still room for process changes and improvements [1]. This paper will present a work procedure for pLCA that grew out of a multi-year project aimed at developing lignin-based carbon fibres for composites (see LIBRE [2]). The intention with this contribution is to provide practitioners guidance on how LCAs in early stages of material development can be handled. 2. Method:The development ofa work procedure for pLCA When starting the LIBRE project, there were no data available for the production of the fibres, and efforts needed to be made to: 1) identify hotspots in the life cycle of carbon fibre composites to show the possible influence of transitioning to a lignin-based fibre, and 2) identify other important routes for decreasing the environmental impact of the composite. This was then done by developing a meta-analysis framework for using results found in available literature on LCAs of carbon fibre reinforced polymers (CFRP) and of lignin production. The results found in the literature were carefully extracted and recalculated to the same functional unit to enable comparisons between studies. The meta-analysis found that a shift to lignin could decrease the environmental impact of carbon fibre composites, but that this is heavily dependent on the allocation approach used to allocate the impacts between co-products at a mill where the lignin is produced. The meta-analysis also identified recycling and recovery of fibres as promising, but that this also is very dependent on how allocation is handled, in this case allocation between life cycles [3]. To explore the influence of the allocation approach for lignin production, allocation approaches found in literature were applied to a case study of the climate impact of lignin extracted from a Kraft pulp mill (see Hermansson et al. [4] for details). In addition, two new allocation approaches were developed: 1) considering the impacts from the lignin extraction process in a subdivision style approach, and 2) partitioning the impacts of the system between energy streams and material streams based on mass conversion, followed by either energy allocation (for energy streams) or mass allocation (for material streams). Results showed that the climate impact of the lignin is highly sensitive to the choice of allocation approach. As the intention was to apply the allocation approaches in a pLCA, they were assessed based on sensitivity to changes in demand for lignin, as this is an aspect of this specific system that could change much over time. The outcome was that many allocation approaches are sensitive to the temporal settings of the study, in particular with regard to prices and/or what is considered the main reason for lignin being extracted from the mill. The influence of allocation approaches in recycling of CFRP was also assessed in a case study. Different allocation approaches were redefined to handle the multiple outputs of both polymer and fibre from composite recycling. The redefined allocation approaches were applied to different fictitious recycling systems that employed different recycling methods. Results showed that the outcome of the assessment is highly dependent on the inherent incentives for recycling in the allocation approaches. For example: The cut- off approach provides no incentive to recycle the product, whereas the end-of-life recycling approach and the circular footprint formula (CFF) do. Recommendations were to, if possible, include both the end-of-life recycling approach and the cut-off approach as two extremes in pLCAs, as the result of the case study showed a large sensitivity to quality and demand for recycled carbon fibres. The CFF, which can be seen as a compromise between the two other allocation approaches but that is dependent on information on the supply and demand for secondary material and therefore challenging to apply in a prospective context, can then be avoided [5]. When different technology routes and allocation approaches had been identified, the findings were applied in a case study of carbon fibre composites in road vehicles (see Hermansson et al. [6]). The technology routes were assessed both separately and grouped into coherent scenarios, as it is likely that some technology development routes will happen simultaneously [7]. By assessing them separately, the individual routes that are most promising for decreasing the environmental impact of the system could be identified. By assessing them together, it was possible to assess under which overarching conditions in society, for example due to aspects related to legislation or R&D funding, the environmental impact would be reduced the most. The end-result, where carbon fibre composites reduced the vehicles’ environmental impact in almost all futures [6], should be seen as an indication of the possible future environmental impacts of the system under study and can provide guidance to technology development. 3. Results,Discussion, and Conclusions The work procedure that grew out of the work in the LIBRE project is visualized in Figure 1. The procedure proved useful for tackling the issue of lack of data in early stages of materials development and helped identifying key parameters in both the technical development and in the surrounding world that would have a large influence on the end result. Figure 1: The procedure for prospective life cycle assessment in materials development, which grew out of the context of assessing carbon-fibre composites Key findings include the usefulness of mining and extracting LCA results from available literature to identify the most important parameters in early stages of materials developments. They also include recommendations on how allocation should be handled for both multi-output processes and recycling systems in pLCAs, also including some new options for multi-output processes. While the procedure was initially used and developed for assessing CFRP, we argue that it is likely applicable to many emerging technologies, especially when the assessment of these face the same types of difficulties in terms of data availability and uncertainties regarding changes to, for example, market demand and prices. 4. References [1] Arvidsson, R., et al., Environmental Assessment of Emerging Technologies: Recommendations for Prospective LCA. Journal of Industrial Ecology, 2018. 22(6): p. 1286-1294. [2] LIBRE. LIBRE-Lignin Based Carbon Fibres for Composites. 2016 [cited 2018 9:th of november]; Available from: http://libre2020.eu. [3] Hermansson, F., M. Janssen, and M. Svanström, Prospective study of lignin-based and recycled carbon fibers in composites through meta-analysis of life cycle assessments. Journal of Cleaner Production, 2019. 223: p. 946-956. [4] Hermansson, F., M. Janssen, and M. Svanström, Allocation in life cycle assessment of lignin. The International Journal of Life Cycle Assessment, 2020. [5] Hermansson, F., et al., Allocation in recycling of composites - the case of life cycle assessment of products from carbon fiber composites. The International Journal of Life Cycle Assessment, 2022. 27(3): p. 419-432. [6] Hermansson, F., et al., Can carbon fiber composites have a lower environmental impact than fiberglass? Resources, Conservation and Recycling, 2022. 181: p. 106234. [7] Langkau, S. and M. Erdmann, Environmental impacts of the future supply of rare earths for magnet applications. Journal of Industrial Ecology, 2021. 25(4): p. 1034-1050. Acknowledgement - This project has received funding from the Bio Based Industries Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 720707 and Chalmers University of Technology - Energy Area of Advance (ECE profile) Transport Area of Advance.
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| 4. |
- Hermansson, Frida, 1988, et al.
(författare)
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Allocation in life cycle assessment of lignin
- 2020
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Ingår i: International Journal of Life Cycle Assessment. - : Springer Science and Business Media LLC. - 1614-7502 .- 0948-3349. ; 25:8, s. 1620-1632
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Lignin extraction in pulp mills and biorefineries are emerging technologies. Lignin is always the product of a multi- output process. Assessing such processes using life cycle assessment (LCA) requires the environmental impacts to be divided between the co-products of the system, referred to as allocation. This article explores different allocation approaches for lignin and illustrates the influence of the choice of allocation approach on the climate impact in a case study. Method Ten different applicable allocation methods were found in literature and two more were developed. Lignin production in a Kraft pulp mill using the LignoBoost process for lignin extraction was selected as a study object for the case study, and due to limited data availability only climate impact was considered. A cradle-to-gate LCA was done for the study object, and all of the twelve allocation approaches were applied; for eight of the methods, factors that strongly influence the results were identified and varied. Finally, the results were put in the context of cradle-to-grave LCAs from literature for different possible uses of lignin to give an indication of how important the choice of allocation approach can be when assessing lignin as a substitute for other raw materials. Results and discussion Results show that all allocation approaches tested were applicable to the special case of lignin, but each one of them comes with inherent challenges. Factors that often have a large impact on the results are (1) market and price of different outputs; (2) what is seen as the main product or the driver of the system or system changes; (3) what the surrounding system looks like and hence what other products will be displaced by outputs. These factors can be particularly challenging in prospective studies as such studies are future-oriented and consider systems that do not yet exist. Finally, the results show that the choice of allocation could have a significant influence on the climate impact on the cradle-to-grave climate impact of the final product. Conclusions We recommend for LCAs of lignin-based technologies that allocation methods are very carefully selected based on the goal and scope of the study and that when relevant, several methods are applied and factors are varied within them in a sensitivity analysis. In particular, the driver(s) of the system’s existence or of changes to it, sometimes reflected in market prices of outputs, should be carefully considered.
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| 5. |
- Hermansson, Frida, 1988, et al.
(författare)
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Allocation in recycling of composites ‐ the case of life cycle assessment of products from carbon fiber composites
- 2022
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Ingår i: International Journal of Life Cycle Assessment. - : Springer Science and Business Media LLC. - 1614-7502 .- 0948-3349. ; 27, s. 419-432
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Composites consist of at least two merged materials. Separation of these components for recycling is typically an energy-intensive process with potentially significant impacts on the components’ quality. The purpose of this article is to suggest how allocation for recycling of products manufactured from composites can be handled in life cycle assessment to accommodate for the recycling process and associated quality degradations of the different composite components, as well as to describe the challenges involved. Method Three prominent recycling allocation approaches were selected from the literature: the cut-off approach, the end- of-life recycling approach with quality-adjusted substitution, and the circular footprint formula. The allocation approaches were adapted to accommodate for allocation of impacts by conceptualizing the composite material recycling as a separation process with subsequent recycling of the recovered components, allowing for separate modeling of the quality changes in each individual component. The adapted allocation approaches were then applied in a case study assessing the cradle- to-grave climate impact and energy use of a fictitious product made from a composite material that in the end of life is recycled through grinding, pyrolysis, or by means of supercritical water treatment. Finally, the experiences and results from applying the allocation approaches were analyzed with regard to what incentives they provide and what challenges they come with. Results and discussion Using the approach of modeling the composite as at least two separate materials rather than one helped to clarify the incentives provided by each allocation approach. When the product is produced using primary materials, the cut-off approach gives no incentive to recycle, and the end-of-life recycling approach and the circular footprint formula give incentives to recycle and recover materials of high quality. Each of the allocation approaches come with inherent challenges, especially when knowledge is limited regarding future systems as in prospective studies. This challenge is most evident for the circular footprint formula, for example, with regard to the supply and demand balance. Conclusions We recommend modeling the composite materials in products as separate, individual materials. This proved useful for capturing changes in quality, trade-offs between recovering high quality materials and the environmental impact of the recycling system, and the incentives the different approaches provide. The cut-off and end-of-life approaches can both be used in prospective studies, whereas the circular footprint formula should be avoided as a third approach when no market for secondary material is established.
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| 6. |
- Hermansson, Frida, 1988, et al.
(författare)
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Assessing efforts to reduce the environmental impacts of carbon fibre composites in vehicles
- 2021
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This presentation will be about the life cycle assessment of different technology development routes for decreasing the environmental impacts of carbon fibre composites in vehicles. Three main routes were assessed: The use of bio-based raw materials for the fibre production, the use of microwave technology in fibre production, and the recycling of the composites and recovery of the fibres after use. The goal was to assess which of these routes that are more promising for making the environmental impacts of carbon fibre composites in vehicles environmentally competitive to glass fibre composites, what aspects that influence this comparison, and what remaining hot spots might be.
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| 7. |
- Hermansson, Frida, 1988, et al.
(författare)
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Can carbon fiber composites have a lower environmental impact than fiberglass?
- 2022
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Ingår i: Resources, Conservation and Recycling. - : Elsevier BV. - 0921-3449 .- 1879-0658. ; 181
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Tidskriftsartikel (refereegranskat)abstract
- Carbon fiber composites are increasingly used to decrease fuel consumption in the use phase of vehicles. However, due to the energy intensive production, the reduced fuel consumption may not lead to life cycle environmental savings as much as for other lightweighting materials, for example fiberglass. This study uses life cycle assessment methodology to assess how different future development routes including using bio-based raw materials, microwave technology, and recycling of composites with the recovery of fibers influence the envi- ronmental impact of both carbon fiber composites and fiberglass in vehicles. Results show that combining different development routes could lead to carbon fiber composites with a lower environmental impact than fiberglass composites in the future and that recycling of composites with recovery of fibers is the route that alone shows the greatest potential.
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| 8. |
- Hermansson, Frida, 1988, et al.
(författare)
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Climate impact and energy use of structural battery composites in electrical vehicles—a comparative prospective life cycle assessment
- 2023
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Ingår i: International Journal of Life Cycle Assessment. - 1614-7502 .- 0948-3349. ; 28:10, s. 1366-1381
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Structural battery composites (SBCs) are multifunctional carbon fibre composites that can be used as structural elements in battery electric vehicles to store energy. By decreasing the weight of the vehicle, energy consumption in the use phase can be reduced, something that could be counteracted by the energy-intensive carbon fibre production. The purpose of this study is to shed light on such life-cycle considerations. Method: Prospective life cycle assessment is used to compare the future cradle-to-grave climate impact and energy use of SBCs in battery electric vehicles to conventional metals and lithium-ion batteries. Additionally, the influences from differ- ent technology development routes, primarily related to the carbon fibre production, are assessed. The functional unit is the roof, hood, and doors of a battery electric vehicle with maintained flexural stiffness used for 200,000 km. To capture the multifunctionality of the material, the lithium-ion battery is also included in the functional unit. Results and discussion: Results show that SBCs have a large potential to decrease the life cycle climate impact and energy use of battery electric vehicles, especially following routes focusing on decreasing the use of fossil resources, both for raw materials and as energy sources. The comparative assessment of multifunctional or recycled materials to conventional mate- rials introduces several methodological challenges, such as defining the functional unit and choice of allocation approach for distributing burdens and benefits between life cycles in recycling. This study illustrates the importance of using both the cut-off and end-of-life recycling allocation approaches to capture extremes and to not provide biased results. This study also highlights the importance of considering the ease of repairability in comparative studies, as damages to car parts made from SBCs are likely more difficult to repair than those made from conventional materials. Conclusions: SBCs have the potential to reduce the life cycle climate impact and energy use for most scenarios compared to conventional materials. Three main methodological challenges were found: the comparison to a material with a well- established recycling system throughout its life cycle, the need for expanding the system boundaries to include the lithium-ion battery, and the difference in repairability of SBCs compared to the conventional material.
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| 9. |
- Hermansson, Frida, 1988, et al.
(författare)
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Lessons learned when assessing emerging composite materials using life cycle assessment
- 2023
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Ingår i: ICCM International Conferences on Composite Materials.
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Konferensbidrag (refereegranskat)abstract
- The modern era of carbon fibres and carbon fibre reinforced polymers (CFRPs) started in the mid 1950s as the U.S. air force Materials Laboratory started producing carbon fibres to develop high strength composites. However, the historically high cost of carbon fibres has until recently kept the use to a small range of applications [1]. It is not until recently that the use of CFRP has become widespread, consequently, CFRP should be considered an emerging material [2]. This makes the environmental assessment difficult as there is a lack of available production data. On the other hand, the emerging nature still makes technology changes possible. This mitchmatch between available data for assessment and production improvements is sometimes referred to as the Collingridge Dilemma. Collingridge described a paradox between information and control: impacts are hard to predict when technology is not yet fully developed, while change becomes more difficult when the technology develops [3]. This paper aims to describe a multi-year effort to use life cycle assessment (LCA) for assessing the environmental impacts of emerging composite materials, focused on the specific example of CFRP. We will describe how we started with a meta-analysis to identify hotspots and key aspects for decreasing the environmental impacts of carbon fibres and CFRPs, to more recent efforts looking into possible future multifunctional use of CFRP for both light-weighting and energy storage in electric vehicles. Results focus on key insights and lessons learned in the process of assessing emerging composite materials using LCA as well as recommendations for decreasing the environmental impacts of carbon fibre composites.
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| 10. |
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