| 1. |
- Xiros, Charilaos, 1973, et al.
(författare)
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Toward a sustainable biorefinery using high-gravity technology
- 2017
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Ingår i: Biofuels, Bioproducts and Biorefining. - : Wiley. - 1932-1031 .- 1932-104X. ; 11:1, s. 15-27
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Tidskriftsartikel (refereegranskat)abstract
- The realization of process solutions for a sustainable bioeconomy depends on the efficient processing of biomass. High-gravity technology is one important alternative to realizing such solutions. The aims of this work were to expand the knowledge-base on lignocellulosic bioconversion processes at high solids content, to advance the current technologies for production of second-generation liquid biofuels, to evaluate the environmental impact of the proposed process by using life cycle assessment (LCA), and to develop and present a technically, economically, and environmentally sound process at high gravity, i.e., a process operating at the highest possible concentrations of raw material. The results and opinions presented here are the result of a Nordic collaborative study within the framework of the HG Biofuels project. Processes with bioethanol or biobutanol as target products were studied using wheat straw and spruce as interesting Nordic raw materials. During the project, the main scientific, economic, and technical challenges of such a process were identified. Integrated solutions to these challenges were proposed and tested experimentally, using wheat straw and spruce wood at a dry matter content of 30% (w/w) as model substrates. The LCA performed revealed the environmental impact of each of the process steps, highlighting the importance of the enzyme dose used for the hydrolysis of the plant biomass, as well as the importance of the fermentation yield.
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| 2. |
- Ahlgren, Serina, et al.
(författare)
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Review of methodological choices in LCA of biorefinery systems - key issues and recommendations
- 2015
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Ingår i: Biofuels, Bioproducts and Biorefining. - : Wiley. - 1932-1031 .- 1932-104X. ; 9:5, s. 606-619
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Forskningsöversikt (refereegranskat)abstract
- The current trend in biomass conversion technologies is toward more efficient utilization of biomass feedstock in multiproduct biorefineries. Many life-cycle assessment (LCA) studies of biorefinery systems have been performed but differ in how they use the LCA methodology. Based on a review of existing LCA standards and guidelines, this paper provides recommendations on how to handle key methodological issues when performing LCA studies of biorefinery systems. Six key issues were identified: (i) goal definition, (ii) functional unit, (iii) allocation of biorefinery outputs, (iv) allocation of biomass feedstock, (v) land use, and (vi) biogenic carbon and timing of emissions. Many of the standards and guidelines reviewed here provide only general methodological recommendations. Some make more specific methodological recommendations, but these often differ between standards. In this paper we present some clarifications (e.g. examples of research questions and suitable functional units) and methodological recommendations (e.g. on allocation).
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| 3. |
- Janssen, Mathias, 1973, et al.
(författare)
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Life cycle assessment of lignin-based carbon fibres
- 2019
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Ingår i: 14th Conference on sustainable development of energy, water and environment systems.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Lignin-based carbon fibres may replace both glass fibres and fossil-based carbon fibres. The objective of this study was to determine the environmental impact of the production of lignin-based carbon fibres using life cycle assessment. The life cycle assessment was done from cradle to gate and followed an attributional approach. The climate impact per kg of lignin- based carbon fibres produced was 1.50 kg CO2,eq. In comparison to glass fibres, the climate impact was reduced by 32% and the climate impact of fossil-based carbon fibres was an order of magnitude higher. A prospective analysis, in which the background energy system was cleaner, showed that the environmental impact of lignin-based carbon fibres will decrease and outperform the glass fibres and fossil-based carbon fibres from a climate impact point-of-view. The constructed LCA model can be applied in further studies of products that consist of or use lignin-based carbon fibres.
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| 4. |
- Janssen, Mathias, 1973, et al.
(författare)
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Life cycle assessment of wood-based ethanol production at high gravity conditions
- 2014
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The development of economically feasible and environmentally benign processes for the production of second generation biofuels is an ongoing effort. The production of bio-ethanol from wood (spruce) using high gravity (high solids content) fermentation is one process concept that is currently under development. Such a process will lead to lower water use in the process, and consequently to lower energy use. However, high gravity conditions have adverse effects on the micro-organisms and high yields are thus not guaranteed. All this will affect the environmental impact of the process. Life cycle assessment (LCA) is used to evaluate the environmental impact of the process along its development path. The main objective of the LCA is to help improve the process under development from an environmental point of view. The LCA is based on the results of lab experiments that were done for the high gravity fermentation process using pretreated spruce as the feedstock. These experiments focused on the process configuration and detoxification strategies in order to increase yields. A spreadsheet model was set up that used the experimental data in order to calculate the mass and energy balances of the system under study, from the harvesting of the wood until the produced ethanol leaves the plant (cradle-to-gate). The results of the mass and energy balances were subsequently used in the LCA model in order to calculate the environmental impact of the ethanol production. The outcomes of the LCA for all the process variants studied were compared in order to identify the weak and strong points of the process. This information can then be used for further development of the technology.This poster presents the results of the LCA based on the lab experiments for this wood-based high gravity process under development. Comparisons are made with wood-based ethanol production using a fermentation process at lower solids content, and with ethanol production using first-generation feedstocks and technology. LCA is thus used during the process development and may potentially have a significant influence on this development, and therefore on the sustainability of 2nd generation biofuels that are produced with a high gravity production process.
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| 5. |
- Janssen, Mathias, 1973, et al.
(författare)
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Life cycle impacts of ethanol production from spruce wood chips under high gravity conditions
- 2016
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Ingår i: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834 .- 1754-6834. ; 9:1, s. 53-
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundDevelopment of more sustainable biofuel production processes is ongoing, and technology to run these processes at a high dry matter content, also called high-gravity conditions, is one option. This paper presents the results of a life cycle assessment (LCA) of such a technology currently in development for the production of bio-ethanol from spruce wood chips.ResultsThe cradle-to-gate LCA used lab results from a set of 30 experiments (or process configurations) in which the main process variable was the detoxification strategy applied to the pretreated feedstock material. The results of the assessment show that a process configuration, in which washing of the pretreated slurry is the detoxification strategy, leads to the lowest environmental impact of the process. Enzyme production and use are the main contributors to the environmental impact in all process configurations, and strategies to significantly reduce this contribution are enzyme recycling and on-site enzyme production. Furthermore, a strong linear correlation between the ethanol yield of a configuration and its environmental impact is demonstrated, and the selected environmental impacts show a very strong cross-correlation (r^2 > 0.9 in all cases) which may be used to reduce the number of impact categories considered from four to one (in this case, global warming potential). Lastly, a comparison with results of an LCA of ethanol production under high-gravity conditions using wheat straw shows that the environmental performance does not significantly differ when using spruce wood chips. For this comparison, it is shown that eutrophication potential also needs to be considered due to the fertilizer use in wheat cultivation.ConclusionsThe LCA points out the environmental hotspots in the ethanol production process, and thus provides input to the further development of the high-gravity technology. Reducing the number of impact categories based only on cross-correlations should be done with caution. Knowledge of the analyzed system provides further input to the choice of impact categories.
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| 6. |
- Liptow, Christin, 1983, et al.
(författare)
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Ethylene based on woody biomass-what are environmental key issues of a possible future Swedish production on industrial scale
- 2013
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Ingår i: International Journal of Life Cycle Assessment. - : Springer Science and Business Media LLC. - 1614-7502 .- 0948-3349. ; 18:5, s. 1071-1081
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Tidskriftsartikel (refereegranskat)abstract
- In order to reduce its environmental impact, the chemical industry no longer produces base chemicals such as ethylene, solely from fossil, but also from biomass-based feedstocks. However, a biomass option suitable for one region might not be as suitable for another region due to, e.g., long transport and the related environmental. Therefore, local biomass alternatives and the environmental impact related to the production of chemicals from these alternatives need to be investigated. This study assesses the environmental impact of producing ethylene from Swedish wood ethanol.The study was conducted following the methodology of life cycle assessment. The life cycle was assessed using a cradle-to-gate perspective for the production of 50,000 tonnes ethylene/year for the impact categories global warming, acidification (ACP), photochemical ozone creation, and eutrophication (EP).The production of enzymes used during the life cycle had a significant effect on all investigated impacts. However, reduced consumption of enzyme product, which could possibly be realized considering the rapid development of enzymes, lowered the overall environmental impact of the ethylene. Another approach could be to use alternative hydrolyzing agents. However, little information on their environmental impact is available. An additional key contributor, with regard to ACP, EP, and POCP, was the ethanol production. Therefore, further improvements with regard to the process' design may have beneficial effects on its environmental impact.The study assessed the environmental impact of wood ethylene and pointed to several directions for improvements, such as improved enzyme production and reduced consumption of enzyme products. Moreover, the analysis showed that further investigations into other process options and increase of ethylene production from biomass are worth continued research.
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| 7. |
- 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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| 8. |
- Arvidsson, Rickard, 1984, et al.
(författare)
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Energy use and climate change improvements of Li/S batteries based on life cycle assessment
- 2018
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753. ; 383, s. 87-92
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Tidskriftsartikel (refereegranskat)abstract
- We present a life cycle assessment (LCA) study of a lithium/sulfur (Li/S) cell regarding its energy use (in electricity equivalents, kWhel) and climate change (in kg carbon dioxide equivalents, CO2 eq) with the aim of identifying improvement potentials. Possible improvements are illustrated by departing from a base case of Li/S battery design, electricity from coal power, and heat from natural gas. In the base case, energy use is calculated at 580 kWhel kWh−1 and climate change impact at 230 kg CO2 eq kWh−1 of storage capacity. The main contribution to energy use comes from the LiTFSI electrolyte salt production and the main contribution to climate change is electricity use during the cell production stage. By (i) reducing cell production electricity requirement, (ii) sourcing electricity and heat from renewable sources, (iii) improving the specific energy of the Li/S cell, and (iv) switching to carbon black for the cathode, energy use and climate change impact can be reduced by 54 and 93%, respectively. For climate change, our best-case result of 17 kg CO2 eq kWh−1 is of similar magnitude as the best-case literature results for lithium-ion batteries (LIBs). The lithium metal requirement of Li/S batteries and LIBs are also of similar magnitude.
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| 9. |
- Arvidsson, Rickard, 1984, et al.
(författare)
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Environmental Assessment of Emerging Technologies: Recommendations for Prospective LCA
- 2018
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Ingår i: Journal of Industrial Ecology. - : Wiley. - 1530-9290 .- 1088-1980. ; 22:6, s. 1286-1294
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Forskningsöversikt (refereegranskat)abstract
- The challenge of assessing emerging technologies with life cycle assessment (LCA) has been increasingly discussed in the LCA field. In this article, we propose a definition of prospective LCA: An LCA is prospective when the (emerging) technology studied is in an early phase of development (e.g., small-scale production), but the technology is modeled at a future, more-developed phase (e.g., large-scale production). Methodological choices in prospective LCA must be adapted to reflect this goal of assessing environmental impacts of emerging technologies, which deviates from the typical goals of conventional LCA studies. The aim of the article is to provide a number of recommendations for how to conduct such prospective assessments in a relevant manner. The recommendations are based on a detailed review of selected prospective LCA case studies, mainly from the areas of nanomaterials, biomaterials, and energy technologies. We find that it is important to include technology alternatives that are relevant for the future in prospective LCA studies. Predictive scenarios and scenario ranges are two general approaches to prospective inventory modeling of both foreground and background systems. Many different data sources are available for prospective modeling of the foreground system: scientific articles; patents; expert interviews; unpublished experimental data; and process modeling. However, we caution against temporal mismatches between foreground and background systems, and recommend that foreground and background system impacts be reported separately in order to increase the usefulness of the results in other prospective studies.
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| 10. |
- Arvidsson, Rickard, 1984, et al.
(författare)
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Potential improvements of the life cycle environmental impacts of a Li/S battery cell
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The lithium sulfur (Li/S) battery is a promising battery chemistry for two reasons: it requires no scarce metals apart from the lithium itself and it brings the promise of high specific energy density at the cell level. However, the environmental impacts of this battery type remain largely unstudied. In this study, we conducted a life cycle assessment (LCA) of the production of an Li/S cell to calculate these impacts. The anode consists of a lithium foil and the cathode consists of a carbon/sulfur composite. The electrolyte is a mixture of dioxalane, dimethoxyethane, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium nitrate. The current collector for the cathode is an aluminium foil and a tri-layer membrane of polypropylene and polyethylene acts as separator. The functional unit of the study is 1 kWh specific energy storage. Three key environmental impacts were considered: energy use, climate change and lithium requirement. In our baseline scenario, we consider the pilot-scale production of a battery with a specific energy of 300 kWh/kg, having the mesoporous material CMK-3 as carbon material in the carbon/sulfur cathode, and using coal power and natural gas heat as energy sources. This scenario results in an energy use of 580 kWh/kWhstored and a climate change impact of 230 kg CO2eq/kWhstored. The main contributor to energy use is the LiTFSI production and the main contributor to climate change is electricity use during cell production. We then model a number of possible improvements sequentially: (1) reduction of cell production electricity requirement due to production at industrial-scale, (2) sourcing of electricity and heat from renewable instead of fossil sources (i.e. solar power and biogas heat), (3) improvement of the specific energy of the Li/S cell to 500 kWh/kg and (4) a shift of the carbon material in the cathode to carbon black (without considering changes in performance). By implementing all these four improvements, energy use and climate change impact can be reduced by an impressive 54 and 93%, respectively. In particular, the improvements related to industrial-scale production and sourcing of renewable energy are considerable, whereas the shift of carbon material is of minor importance. For climate change, the best-case result of 17 kg CO2eq/kWhstored is similar to the best-case results reported in the scientific literature for lithium-ion batteries (LIBs). Regarding lithium requirement, the lithium metal requirement of Li/S batteries and LIBs are also of similar magnitude (0.33-0.55 kg/kWhstored and 0.2 kg/kWhstored, respectively). Using different allocation approaches did not alter the main conclusions of the study.
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