| 1. |
- Yucel, Yasemin Duygu, et al.
(författare)
-
Powder-impregnated carbon fibers with lithium iron phosphate as positive electrodes in structural batteries
- 2023
-
Ingår i: Composites Science And Technology. - : Elsevier Ltd. - 0266-3538 .- 1879-1050. ; 241
-
Tidskriftsartikel (refereegranskat)abstract
- A structural battery is a multifunctional battery that can carry a load while storing energy. Structural batteries have been a cutting-edge research focus in the last decade and are mainly based on polyacrylonitrile (PAN)-carbon fibers (CFs). In this work, positive electrodes based on PAN-carbon fibers were manufactured with powder impregnation (siphon impregnation) technique using a water-based slurry containing lithium iron phosphate (LFP) as the active electrode material and the water-soluble binder polyethylene glycol (PEG). Different coating compositions, electrode-drying temperatures, and coating parameters were investigated to optimize the coating uniformity and the electrochemical performances. Scanning electron microscopy results showed that the electrode materials coat the CFs uniformly, conformably, and individually. Electrochemical characterization of pouch cells shows that the electrodes containing 6 wt% PEG dried at 140 °C have the best battery performance, delivering a first discharge capacity of 151 mAh g−1 and capacity retention higher than 80% after 100 cycles. Moreover, excellent capacity reversibility was achieved when the electrodes were cycled at multiple C-rates attesting to their stability. The results demonstrate that CFs perform excellently as current collectors in positive electrodes.
|
|
| 2. |
- Bergenhem, Carl, et al.
(författare)
-
Overview of platooning systems
- 2012
-
Ingår i: Proceedings of the 19th ITS World Congress. ; , s. 1-7
-
Konferensbidrag (refereegranskat)abstract
- This paper presents an overview of current projects that deal with vehicle platooning. The platooning concept can be defined as a collection of vehicles that travel together, actively coordinated in formation. Some expected advantages of platooning include increased fuel and traffic efficiency, safety and driver comfort. There are many variations of the details of the concept such as: the goals of platooning, how it is implemented, mix of vehicles, the requirements on infrastructure, what is automated (longitudinal and lateral control) and to what level. The following projects are presented: SARTRE – a European platooning project; PATH – a California traffic automation program that includes platooning; GCDC – a cooperative driving initiative, SCANIA platooning and; Energy ITS – a Japanese truck platooning project.
|
|
| 3. |
- Furusjö, Erik, 1972-, et al.
(författare)
-
Mixing of Fast Pyrolysis Oil and Black Liquor : Preparing an Improved Gasification Feedstock
- 2016
-
Ingår i: Energy & Fuels. - : American Chemical Society. - 0887-0624 .- 1520-5029. ; 30:12, s. 10575-10582
-
Tidskriftsartikel (refereegranskat)abstract
- Co-gasification of fast pyrolysis oil and black liquor can be used to increase the size and improve profitability of pulp mill integrated biorefineries. The acids present in pyrolysis oil limit the amount that can be mixed into black liquor without causing precipitation of the black liquor dissolved lignin. This work shows that a simple model based on pyrolysis oil total acid number, including weak phenolic acids, can be used to predict the maximum pyrolysis oil fraction in blends. The maximum oil fraction is 20-25% for typical pyrolysis oil but can be increased up to at least 50% mass, corresponding to 70% energy, by addition of base. Thermodynamic equilibrium calculations are used to understand the effects of blend composition, including any added base, on the performance of a commercial scale gasification process. A substantial increase in overall gasification efficiency is observed with increasing pyrolysis oil fraction.
|
|
| 4. |
- Jafri, Yawer, 1988-, et al.
(författare)
-
Double Yields and Negative Emissions? : Resource, Climate and Cost Efficiencies in Biofuels With Carbon Capture, Storage and Utilization
- 2022
-
Ingår i: Frontiers in Energy Research. - : Frontiers Media S.A.. - 2296-598X. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- As fossil-reliant industries turn to sustainable biomass for energy and material supply, the competition for biogenic carbon is expected to intensify. Using process level carbon and energy balance models, this paper shows how the capture of residual CO2 in conjunction with either permanent storage (CCS) or biofuel production (CCU) benefits fourteen largely residue-based biofuel production pathways. With a few noteworthy exceptions, most pathways have low carbon utilization efficiencies (30–40%) without CCS/U. CCS can double these numbers and deliver negative emission biofuels with GHG footprints below −50 g CO2 eq./MJ for several pathways. Compared to CCS with no revenue from CO2 sequestration, CCU can offer the same efficiency gains at roughly two-third the biofuel production cost (e.g., 99 EUR/MWh vs. 162 EUR/MWh) but the GHG reduction relative to fossil fuels is significantly smaller (18 g CO2 eq./MJ vs. −99 g CO2 eq./MJ). From a combined carbon, cost and climate perspective, although commercial pathways deliver the cheapest biofuels, it is the emerging pathways that provide large-scale carbon-efficient GHG reductions. There is thus some tension between alternatives that are societally best and those that are economically most interesting for investors. Biofuel pathways vent CO2 in both concentrated and dilute streams Capturing both provides the best environomic outcomes. Existing pathways that can deliver low-cost GHG reductions but generate relatively small quantities of CO2 are unlikely to be able to finance the transport infrastructure required for transformative bio-CCS deployment. CCS and CCU are accordingly important tools for simultaneously reducing biogenic carbon wastage and GHG emissions, but to unlock their full benefits in a cost-effective manner, emerging biofuel technology based on the gasification and hydrotreatment of forest residues need to be commercially deployed imminently. Copyright © 2022 Jafri, Ahlström, Furusjö, Harvey, Pettersson, Svensson and Wetterlund.
|
|
| 5. |
- Lindgren, M., et al.
(författare)
-
Styrene emissions from the spray-up and vacuum injection processes - A quantitative comparison
- 2002
-
Ingår i: AIHAJ - Journal of Occupational and Environmental Hygiene. - : Informa UK Limited. - 1529-8663 .- 2163-3711. ; 63:2, s. 184-189
-
Tidskriftsartikel (refereegranskat)abstract
- Styrene emissions were studied during manufacturing of two identical glass-fiber reinforced plastic boats by two different manufacturing methods. The manufacturing methods were spray-up, which is an open method, and vacuum injection, which is a closed method. Changing the manufacturing process from an open method to a closed method decreased the styrene evaporation dramatically in this particular case. By using vacuum injection, the styrene emission during the laminate application was reduced by 98% compared with the styrene emission during laminate application by spray-up. Gel coat application by spraying will remain a major source for styrene emissions. The greatest environmental benefit is achieved with closed manufacturing methods when products without gel coat are made. The whole manufacturing process can then be performed in a closed system virtually free from emissions.
|
|
| 6. |
- Marais, Andrew, et al.
(författare)
-
Pilot-scale papermaking using Layer-by-Layer treated fibres; comparison between the effects of beating and of sequential addition of polymeric additives
- 2016
-
Ingår i: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter GmbH. - 0283-2631 .- 2000-0669. ; 31:2, s. 308-314
-
Tidskriftsartikel (refereegranskat)abstract
- The Layer-by-Layer (LbL) deposition technique was used to treat fibres before papermaking on a pilot scale. Following a laboratory pre-study performed earlier to determine the adsorption isotherms and the kinetics of formation of multilayers of polyamideamine epichlorydrine (PAE) and carboxymethylated cellulose (CMC) on unbeaten, bleached softwood fibres, online LbL treatment of the furnish was carried out on the EuroFEX pilot paper machine. Papers from fibres coated with up to four layers of polyelectrolytes were produced. Two different LbL systems were investigated, with anionic CMC in combination with either PAE or cationic starch (CS). The results showed that the mechanical strength of the paper significantly increased when the fibres were LbL-treated online. A comparison with conventional beating of the fibres revealed that the LbL treatment was a potential substitute to beating treatment, as the density of the LbL-treated papers remained constant while the mechanical properties were significantly improved. At the same time, the press solids content was significantly higher (2%) when using LbL-treated fibres than with beaten fibres.
|
|
| 7. |
- Pettersson, Karin, et al.
(författare)
-
Holistic methodological framework for assessing the benefits of delivering industrial excess heat to a district heating network
- 2020
-
Ingår i: International Journal of Energy Research. - : John Wiley and Sons Ltd. - 0363-907X .- 1099-114X. ; 44:4, s. 2634-2651
-
Tidskriftsartikel (refereegranskat)abstract
- In Sweden, over 50% of building heating requirements are covered by district heating. Approximately 8% of the heat supply to district heating systems comes from excess heat from industrial processes. Many studies indicate that there is a potential to substantially increase this share, and policies promoting energy efficiency and greenhouse gas emissions reduction provide incentives to do this. Quantifying the medium and long-term economic and carbon footprint benefits of such investments is difficult because the background energy system against which new investments should be assessed is also expected to undergo significant change as a result of the aforementioned policies. Furthermore, in many cases, the district heating system has already invested or is planning to invest in non-fossil heat sources such as biomass-fueled boilers or CHP units. This paper proposes a holistic methodological framework based on energy market scenarios for assessing the long-term carbon footprint and economic benefits of recovering excess heat from industrial processes for use in district heating systems. In many studies of industrial excess heat, it is assumed that all emissions from the process plant are allocated to the main products, and none to the excess heat. The proposed methodology makes a distinction between unavoidable excess heat and excess heat that could be avoided by increased heat recovery at the plant site, in which case it is assumed that a fraction of the plant emissions should be allocated to the exported heat. The methodology is illustrated through a case study of a chemical complex located approximately 50 km from the city of Gothenburg on the West coast of Sweden, from which substantial amounts of excess heat could be recovered and delivered to heat to the city's district heating network which aims to be completely fossil-free by 2030.
|
|
| 8. |
- Pompe, Robert, et al.
(författare)
-
How to screen high temperature steels for optimal use in biofuel-heated burners for residential boilers: Role of alkali
- 2011
-
Ingår i: NACE - International Corrosion Conference Series. - 0361-4409. ; , s. 12p-
-
Konferensbidrag (refereegranskat)abstract
- Hot parts of burners for residential boilers are subject to irregular heating cycles up to 800 °C and higher, simultaneously exposed to alkali salts, variable oxygen partial pressure - and thermal shock. Fundamental hot corrosion studies under well-controlled conditions, in combination with simple ranking tests simulating the effect of ash deposited on the alloy surface, have been performed. The investigation included four types of high-alloyed steel and two types of ash from wood and bark pellets. The work was complemented with field studies of selected damaged parts. Two mechanisms involving interaction of potassium as well as carbon under intermittent oxygen-deficient conditions with chromium from the alloys have been corroborated. A simple ranking test procedure has also been designed. It proved relevant as a screening method only after incorporating a mild thermal shock in the heat treatment sequence. A significant difference in corrosive effect, particularly on a lower chromium-alloy like 304 L, has been observed for the ash derived from the wood and bark pellets, respectively.
|
|
| 9. |
- Simonsson, Johan, et al.
(författare)
-
Soot Concentrations in an Atmospheric Entrained Flow Gasifier with Variations in Fuel and Burner Configuration Studied Using Diode-Laser Extinction Measurements
- 2016
-
Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 30:3, s. 2174-2186
-
Tidskriftsartikel (refereegranskat)abstract
- Soot concentration measurements were performed using diode-laser extinction in an atmospheric air-blown entrained flow gasifier at two vertical levels. The gasifier was operated at different air-fuel equivalence ratios and with variations in fuel and burner configurations. Two fuels were investigated: wood powder and peat powder. These were burned using two burner configurations, one giving a rotating flow inside the gasifier (swirl), and one where the fuel and air were injected parallel with the gasifier axis (jet). The diode-laser measurements were performed at the wavelength 808 nm from which the soot concentrations were estimated, and additionally at 450 nm in order to gain insight into the spectral dependence of the extinction to estimate measurement quality. Additional diagnostic techniques were used, such as an electrical low-pressure impactor (ELPI) for soot size distributions and gas chromatography for species concentration measurements. The results show that wood powder produces higher soot concentrations than peat powder, especially at lower air-fuel equivalence ratios. Furthermore, the burner configuration had in general much less impact than the choice of fuel on the soot concentration.
|
|
| 10. |
- Smith, Kevin W., et al.
(författare)
-
Slow recrystallization of tripaimitoylglycerol from MCT oil observed by H-2 NMR
- 2007
-
Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 55:21, s. 8585-8588
-
Tidskriftsartikel (refereegranskat)abstract
- The crystallization and recrystallization of fats have a significant impact on the properties and quality of many food products. While crystallization has been the subject of a number of studies using pure triacylglycerols (TAG), recrystallization in similarly pure systems is rarely studied. In this work, percleuterated tripalmitoylglycerol (H-2-PPP) was dissolved in medium chain triacylglycerol oil (MCT) to yield a saturated solution. The solution was heated to cause partial melting of the solid and dissolution of the molten fraction of H-2-PPP in MCT and was then cooled to the original temperature to induce recrystallization from the supersaturated solution. H-2 NMR was used to monitor the disappearance of H-2-PPP from the solution and showed that recrystallization occurred in two steps. The first step was rapid, taking place over a few minutes, and accounted for more than two-thirds of the total recrystallization. The second step was much slower, taking place over a remarkably long timescale of hours to days. It is proposed that dissolution occurs from all parts of the crystals, leaving an etched and pitted surface. The first step of crystallization is the infilling of these pits, while the second step is the continued growth on the smoothed crystal faces.
|
|
