| 1. |
- Ahmadi Moghaddam, Elham, et al.
(författare)
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Assessment of Novel Routes of Biomethane Utilization in a Life Cycle Perspective
- 2016
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Ingår i: Frontiers in Bioengineering and Biotechnology. - : Frontiers Media SA. - 2296-4185. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Biomethane, as a replacement for natural gas, reduces the use of fossil-based sources and supports the intended change from fossil to bio-based industry. The study assessed different biomethane utilization routes for production of methanol, dimethyl ether (DME), and ammonia, as fuel or platform chemicals and combined heat and power (CHP). Energy efficiency and environmental impacts of the different pathways was studied in a life cycle perspective covering the technical system from biomass production to the end product. Among the routes studied, CHP had the highest energy balance and least environmental impact. DME and methanol performed competently in energy balance and environmental impacts in comparison with the ammonia route. DME had the highest total energy output, as fuel, heat, and steam, among the different routes studied. Substituting the bio-based routes for fossil-based alternatives would give a considerable reduction in environmental impacts such as global warming potential and acidification potential for all routes studied, especially CHP, DME, and methanol. Eutrophication potential was mainly a result of biomass and biomethane production, with marginal differences between the different routes.
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| 2. |
- Ahmadi Moghaddam, Elham, et al.
(författare)
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Energy balance and global warming potential of biogas-based fuels from a life cycle perspective
- 2015
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Ingår i: Fuel Processing Technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 132, s. 74-82
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Tidskriftsartikel (refereegranskat)abstract
- Biogas is a multifunctional energy carrier currently used for co-generation or compressed biomethane as vehicle fuel. Gas-to-liquid (GTL) technology enables conversion of biogas into other energy carriers with higher energy density, facilitating fuel distribution. The energy efficiency and global warming potential (GWP) for conversion of biogas to compressed biogas (CBG), liquefied biogas (LBG), Fischer–Tropsch diesel (FTD), methanol and dimethyl ether (DME) were studied in a life cycle perspective covering the technical system from raw biogas to use in city buses. CBG, methanol and DME showed the best specific fuel productivity. However, when fuel distribution distances were longer, DME, LBG and methanol showed the best energy balance. Methanol, FTD and DME emitted half the GWP of LBG and CBG. Choice of electricity mix had a large impact on GWP performance. Overall, taking into account the different impact categories, combustion properties and fuel yield from raw biogas, DME showed the best performance of the fuel conversion scenarios assessed.
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| 3. |
- Ahmadi Moghaddam, Elham, et al.
(författare)
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Exploring the potential for biomethane production by willow pyrolysis using life cycle assessment methodology
- 2019
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Ingår i: Energy, Sustainability and Society. - : Springer Science and Business Media LLC. - 2192-0567. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundBiomethane, as a potential substitute for natural gas, reduces the use of fossil-based sources, promoting bioenergy applications. Biomethane for energy use can be produced using a variety of biomass types and technologies. Biomethane from farmland crops is currently produced by anaerobic digestion (AD) of energy crops, which is a biological treatment of organic material resulting in biomethane and digestate. Recently, thermochemical conversion technologies of biomass to biomethane have gained attention. Pyrolysis is a thermochemical process whereby woody biomass is converted to fuel gas and biochar. This study assessed the land use efficiency of producing biomethane through a maize-based AD system compared with switching to a willow-based biomethane system using pyrolysis as an emerging technology. The energy performance and climate impact of the two pathways were assessed from a land use perspective, using life cycle assessment methodology. The entire technical system, from biomass production to delivery of biomethane as the end product, was included within the analysis. The study also investigated how the climate impact was affected when biochar was applied to soil to act as a soil amendment and carbon sequestration agent or when biochar was used as an energy source.ResultsPyrolysis of willow had a higher external energy ratio and climate mitigation effect than maize-based AD as a result of lower primary energy inputs and lower methane loss in the pyrolysis process and upgrading units. Furthermore, the biochar from willow pyrolysis, when used as a soil amendment or energy source, contributed significantly to the climate impact mitigation potential in both cases. Substituting fossil gas with biomethane gave a considerable reduction in climate impact in all scenarios, especially in the case of willow pyrolysis. The willow pyrolysis system acted as a carbon sink, resulting in a negative climate impact, counteracting global warming.ConclusionFrom a land use perspective, the transition from maize-based AD to a willow-based pyrolysis system for biomethane production could be beneficial regarding the energy performance and climate impact. Application of biochar to the soil in the willow scenario contributed significantly to counteracting emissions of greenhouse gases.
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| 4. |
- Ahmadi Moghaddam, Elham, et al.
(författare)
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Gas Hydrates as a Means for Biogas and Biomethane Distribution
- 2021
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Ingår i: Frontiers in Energy Research. - : Frontiers Media SA. - 2296-598X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Biomethane is receiving great attention as a renewable energy gas with lower environmental impacts and diversified sources of production. However, availability of gas infrastructure is an important factor in biomethane development and use. Biomethane can be distributed by the natural gas or local biogas grid. Biomethane can also be road-transported as compressed biomethane (CBG) or liquefied bio-methane (LBG). Biomethane could be distributed via gas hydration technology, where methane molecules are physically trapped within the crystalline structures of frozen host water molecules as gas hydrate compounds. Using life cycle assessment methodology, this study compared the energy performance and climate impact of two gas hydrate scenarios, biogas hydrate and biomethane hydrate, with that of a base case distributing biomethane as CBG. The technical system, from biogas upgrading, hydration, compression and road transport to filling station of biomethane as CBG, was included in the analysis. Results of this study show that distribution of biomethane as gas hydrates had a lower energy performance and higher climate impact than compressed biomethane distribution. The low energy performance was due to high electricity demand in hydrate formation and dissociation processes. The gas hydrate scenarios also had higher climate impacts as a result of high methane losses from hydrate formation and dissociationdissociation and emissions related to energy source use. Biogas upgrading to biomethane also significantly contributed to methane losses and climate impact of the scenarios studied.
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| 5. |
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| 6. |
- Ahmadi Moghaddam, Elham
(författare)
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Life Cycle Assessment of Novel Biomethane Systems : energy performance and climate impact
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Climate mitigation and supply of renewable energy are global challenges. The main cause of climate change is anthropogenic activities, including consumption of fossil energy sources and land use change. Biomethane, a biomass-derived renewable energy carrier, is interchangeable with fossil-based natural gas and can provide energy services (e.g. heat, electricity and vehicle fuel) and high-value products such as chemicals. However, the availability of feedstock suitable for anaerobic digestion, the limited grid infrastructure in certain regions and problems relating to storage and distribution are barriers to increased deployment of biomethane systems. This thesis aims to provide decision support for the development and implementation of future biomethane systems, by describing the energy performance and climate impact of some promising novel technologies related to biomethane production, conversion of biomethane to high-value products and biomethane distribution in a life cycle perspective. Anaerobic digestion of maize and pyrolysis of willow for production of biomethane were assessed and compared, while gas-to-liquid (GTL) technologies were studied as potential routes for conversion of biomethane to liquid transportation fuels or platform chemicals. Gas hydrates were assessed as a means of biomethane distribution. The results showed that transition from maize-based anaerobic digestion to willowbased pyrolysis for biomethane production improved energy performance (higher external energy ratio) and environmental performance (lower climate impact), mainly due to buildup of soil organic carbon and use of biochar as a soil amendment or as an energy source to replace fossil coal. Use of biomethane for production of dimethyl ether as a GTL fuel was competitive relative to the conventional compressed biomethane system regarding energy performance and climate impact. Formation and disassociation of gas hydrates was associated with high energy use, and thus technological development is required to overcome the high primary energy inputs and related high climate impact of gas hydrate distribution.
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| 7. |
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| 8. |
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| 9. |
- Höglund, Jonas, et al.
(författare)
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Biofuels and land use in Sweden: an overview of land-use change effects
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Supported by policies, biofuel production has been continuously increasing worldwide during recent years. However, concerns have been raised that biofuels, often advocated as the future substitute for greenhouse gas (GHG) intensive fossil fuels, may cause negative effects on the climate and the environment. When assessing GHG emissions from biofuels, the production phase of the biofuel crop is essential since this is the phase in which most of the GHG emissions occur during the life cycle of the fuel, often linked to land use and land management. Changes in land use can result from a wide range of anthropogenic activities including agriculture and forestry management, livestock and biofuel production. The report first presents a review of the literature in the different scientific areas related to land use change (LUC) and biofuel production. Knowledge gaps related to LUC is compiled and, a synthesis is developed highlighting major challenges and key findings. Main findings are that (i) deforestation, forest management, and climate change deforestation is a major contributor to GHG emissions and can contribute to soil erosion and carbon stock changes, (ii) albedo changes and the timing of emissions need to be better understood, (iii) to avoid degradation of biodiversity great care must be taken to develop sustainable biofuel production (iv) nutrient leakage and removal of forest residues can influence the biomass growth potential (v) to avoid fertility losses in agricultural soils during biofuel production, crops with low fertilizer needs, high nutrient use efficiency and high yields should be given priority (vi) indirect effects on land use are extremely complex to quantify without great uncertainty (vii) biofuels contribution to rising food prices and poverty even more challenging (viii) biofuel production can create jobs but also interfere with traditional ways of life and recreational values, (ix) to avoid negative effects, biofuel production should be developed in collaboration with the stakeholders involved: farmers, land owners, tourists, and industry. The literature review and synthesis presented in this report shows that land use on this planet is already placing high stress on ecosystems, atmosphere, soils and human life. Because of increased biofuel production, land use change is therefore at risk of aggravating these problems. Conclusions drawn are that the LUC caused by increasing use of biofuels can be negative to various degrees but that drawbacks can be mitigated through policy measures or technology developments. Examples include the cultivation of high-yielding crops, cultivation on abandoned arable land, and effective use of by-products and waste. To explore the opportunities that exist for beneficial land use change, continued responsible and sensitive collaboration between industry, policy-makers, researchers and local communities is a prerequisite.
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| 10. |
- Sattari, Amir, 1980-, et al.
(författare)
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INDUSTRIAL NANOPARTICLES HEALTH RISKS AND ADVANTAGES OF A DECENT INDUSTRIAL VENTILATION SYSTEM IN REDUCING THE RELATED RISKS
- 2012
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Ingår i: INDUSTRIAL NANOPARTICLES HEALTH RISKS AND ADVANTAGES OF A DECENT INDUSTRIAL VENTILATION SYSTEM IN REDUCING THE RELATED RISKS. ; , s. -6
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Konferensbidrag (refereegranskat)abstract
- With the fast-growing use of nanoparticles (NPs) in a wide range of production and manufacturing processes, and great health and environmental risks associated to NPs, it is important to treat the industry-produced NPs in a proper way. Ventilation of industrial workplaces lies within the concept of sustainability challenges for the development of nanoproducts. Due to the decreased grain size of material to nano limits and thus the appearance of either new or changed properties, health risk of workers in such environments is critical concerning the complicated and unknown characteristics of nanoparticles. There is great evidence over the past few years that ultrafine particles and especially NPs in the breathing air are strong toxins. Different mitigation measures for air-borne nanoparticles in industrial workplaces are substitution, engineering controls such as ventilation and provision of personal protective equipment. In this paper selection criteria for ventilation systems and different ventilation methods (hood ventilation and global enclosure/room ventilation systems) as engineering controls of nanoparticles within industrial enclosures will be reviewed. Novel methods for improvement of ventilation efficiency in general and industrial work places with an eye on ventilation of nanoparticles will be presented.
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