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| 2. |
- Halvarsson, Sören, 1956-
(författare)
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Manufacture of straw MDF and fibreboards
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this thesis was to develop an economical, sustainable, and environmentally friendly straw Medium Density Fibreboard (MDF) process, capable of full-scale manufacturing and to produce MDF of requested quality. The investigated straw was based on wheat (Triticum aestivum L.) and rice (Oryzae sativa L.). In this thesis three different methods were taken for manufacture of straw MDF; (A) wheat-straw fibre was blowline blended with melamine-modified urea-formaldehyde (MUF), (B) rice-straw fibre was mixed with methylene diphenyl diisocyanate (MDI) in a resin drum-blender, and (C) wheat-straw fibre was activated in the blowline by the addition of Fenton’s reagent (H2O2/Fe2+) for production of non-resin MDF panels. The MUF/wheat straw MDF panels were approved according to the requirements of the EN standard for MDF (EN 622-5, 2006). The MDI/rice-straw MDF panels were approved according to requirements of the standard for MDF of the American National Standard Institute (ANSI A208.2-2002). The non-resin wheat-straw panels showed mediocre MDF panel properties and were not approved according to the requirements in the MDF standard. The dry process for wood-based MDF was modified for production of straw MDF. The straw MDF process was divided into seven main process steps. 1. Size-reduction (hammer-milling) and screening of straw 2. Wetting and heating of straw 3. Defibration 4. Resination of straw fibre 5. Mat forming 6. Pre-pressing 7. Hot-pressing The primary results were that the straw MDF process was capable of providing satisfactory straw MDF panels based on different types of straw species and adhesives. Moreover, the straw MDF process was performed in pilot-plant scale and demonstrated as a suitable method for producing straw MDF from straw bales to finished straw MDF panels. In the environmental perspective the agricultural straw-waste is a suitable source for producing MDF to avoid open field burning and to capture carbon dioxide (CO2), the biological sink for extended time into MDF panels, instead of converting straw directly into bio energy or applying straw fibre a few times as recycled paper. Additionally, the straw MDF panels can be recycled or converted to energy after utilization. A relationship between water retention value (WRV) of resinated straw fibres, the thickness swelling of corresponding straw MDF panels, and the amount of applied adhesive was determined. WRV of the straw fibre increased and the TS of straw MDF declined as a function of the resin content. The empirical models developed were of acceptable significance and the R2 values were 0.69 (WRV) and 0.75 (TS), respectively. Reduced thickness swelling of MDF as the resin content is increased is well-known. The increase of WRV as a function of added polymers is not completely established within the science of fibre swelling. Fortunately, more fundamental research can be initiated and likely a simple method for prediction of thickness swelling of MDF by analysis of the dried and resinated MDF fibres is possible.
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| 3. |
- Brandin, Jan, 1958-, et al.
(författare)
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Multi-function catalysts for glycerol upgrading
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- During the last three years Biofuel-Solution, a privately held Swedish entity, has developed an IP-portfolio around gas-phase glycerol conversion into medium-value chemicals. The targeted chemicals have large to very large markets, to allow for use by more than a fraction of the glycerol available today without impacting the cost of the product. The reason behind is that glycerol is a by-product from the biofuel industry, including biodiesel and bioethanol. This indicates large production volumes, even though the glycerol is a fraction of the fuel produced. A by-product from any fuel process will be vast and therefore any chemical produced from this side-product will have to have a large market to offset it to. In order to avoid changing the fundamental market behavior, similar to what the biodiesel industry has done to the glycerol market. In the course of this work, several end-products have been targeted. These include plastic monomers, mono-alcohols and energy gases; using acrolein as a common starting point. To produce chemicals with high purity and efficiency, selective and active catalysts are required. For instance, a process for producing propionaldehyde and n-propanol has been developed to the point of demonstration and commercialization building on the gas-phase platform. By developing multi-function catalysts which perform more than one task simultaneously, synergies can be reached that cannot be achieved with traditional catalysts. For instance, by combining catalyst functionalities, reactions that are both endothermic and exothermic can be performed simultaneously. This mean lower inlet reactor temperatures (in this particular case) and a more even temperature distribution. By performing the dehydration of glycerol to acrolein in combination with another, exothermal reaction by-products can be suppressed and yields increased. It also means that new reaction pathways can be achieved, allowing for new ways to produce chemicals and fuels from glycerol. As in the case of ethane production from acrolein, where a catalyst surface has been devised where acrolein is first adsorbed. The actual mechanism is unknown but in speculation, the adsorbed acrolein is decarbonyled into ethylene and carbon monoxide on a first reaction site. The formed carbon monoxide diffuses to another active site, where it reacts with water through the so called water-gas shift reaction to carbon dioxide and hydrogen. Said carbon dioxide leaves as an end-product, and the hydrogen diffuses to another active site where it reacts with ethylene to form ethane. This gives a way of producing energy gases from glycerol in a very compact reactor set-up, effectively reducing footprint and capital cost and increasing productivity of an installation.
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| 4. |
- Ström, Henrik, 1981, et al.
(författare)
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Numerical simulations of the interaction between a settling particle and a rising microbubble
- 2012
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Ingår i: AIP Conference Proceedings. - : AIP. - 1551-7616 .- 0094-243X. ; 1479:1, s. 113-116
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Konferensbidrag (refereegranskat)abstract
- In the current work the hydrodynamic interaction between a settling particle and a rising microbubble is investigated using numerical simulations. The simulations are performed in a multiphase direct numerical simulation (DNS) framework, indicating that all relevant spatial and temporal scales are resolved. It is shown that the method predicts that particle-bubble attachment is possible when the initial horizontal distance between their centers is small and that the particle will pass the bubble without attaching when this initial distance is large. Furthermore, it is shown that the probability of a successful attachment is lower if the bubble Eötvös and Morton numbers are significantly larger than unity.
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| 5. |
- Eriksson, Gunnar, et al.
(författare)
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Combustion and fuel characterisation of wheat distillers dried grain with solubles (DDGS) and possible combustion applications
- 2012
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Ingår i: Fuel. - : Elsevier. - 0016-2361 .- 1873-7153. ; 102, s. 208-220
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Tidskriftsartikel (refereegranskat)abstract
- The present transition to a sustainable global energy system requires that biomass is increasingly combusted for heat and power production. Agricultural fuels considered include alkali-rich fuels with high phosphorus content. One such fuel is wheat distiller’s dried grain with solubles (wheat DDGS) from wheat-based ethanol production. Further increases in ethanol production may saturate the current market for wheat DDGS as livestock feed, and fuel uses are therefore considered. Fuel properties of wheat DDGS have been determined. The ash content (5.4 ± 1.6 %wt d.s.) is similar to many agricultural fuels. In comparison to most other biomass fuels the sulphur content is high (0.538 ± 0.232 %wt d.s.), and so are the contents of nitrogen (5.1 ± 0.6 %wt d.s.), phosphorus (0.960. ± 0.073 %wt d.s.) and potassium (1.30 ± 0.35 %wt d.s.). To determine fuel-specific combustion properties, wheat DDGS and mixes between wheat DDGS and logging residues (LR 60 %wt d.s. and DDGS 40 %wt d.s.), and wheat straw (wheat straw 50 %wt d.s., DDGS 50 %wt d.s.) were pelletized and combusted in a bubbling fluidised bed combustor (5 kW) and in a pellets burner combustor (20 kW). Pure wheat DDGS powder was also combusted in a powder burner (150 kW). Wheat DDGS had a high bed agglomeration and slagging tendency compared to other biomass fuels, although these tendencies were significantly lower for the mixture with the Ca-rich LR, probably reflecting the higher first melting temperatures of K–Ca/Mg-phosphates compared to K-phosphates. Combustion and co-combustion of wheat DDGS resulted in relatively large emissions of fine particles (<1 μm) for all combustion appliances. For powder combustion PMtot was sixteen times higher than from softwood stem wood. While the Cl concentrations of the fine particles from the the mixture of LR and wheat DDGS in fluidised bed combustion were lower than from combustion of pure LR, the Cl- and P-concentrations were considerably higher from the wheat DDGS mixtures combusted in the other appliances at higher fuel particle temperature. The particles from powder combustion of wheat DDGS contained mainly K, P, Cl, Na and S, and as KPO3 (i.e. the main phase identified with XRD) is known to have a low melting temperature, this suggests that powder combustion of wheat DDGS should be used with caution. The high slagging and bed agglomeration tendency of wheat DDGS, and the high emissions of fine particles rich in K, P and Cl from combustion at high temperature, mean that it is best used mixed with other fuels, preferably with high Ca and Mg contents, and in equipment where fuel particle temperatures during combustion are moderate, i.e. fluidised beds and possibly grate combustors rather than powder combustors.
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| 6. |
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| 7. |
- Ström, Henrik, 1981
(författare)
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Numerical simulations of reacting nano-scale flows
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The outcome of the CheSC pilot project "Numerical simulations of reacting nano-scale flows" is reported. A Direct Simulation Monte Carlo (DSMC) code has been developed that is able to treat molecular motion in wall-bounded systems with a prescribed pressure difference between an inlet and an outlet. Both homogeneous and heterogeneous chemical reactions can be handled by the code. A number of validation cases are presented to support these claims.An algorithm has been devised and implemented that allows optimization of the distribution of a catalytically active material within a 3D pore where the flow field is described by the present code. The objective function is the outlet concentration of computational molecules that have interacted with the catalytically active surface, and the optimization method used is simulated annealing. The application of a stochastic optimization heuristic is shown to be more efficient within the present DSMC framework than using a macroscopic overlay method. Furthermore, it is shown that the performance of the developed method is superior to that of a gradient search method for the current class of problems.The code produced in the current project represents a suitable starting-point for addressing a number of related research questions, such as reacting multiphase flows on the nano-scale and reacting heterogeneous flows with surface diffusion. The report also contains a discussion on how the present code can be extended to allow for a detailed investigation of these issues.
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| 8. |
- Bylin, Susanne, 1982
(författare)
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Mechanisms of Biopolymer Solvation: Development of a two-component ionic liquid solvent system
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ionic liquids are of potential interest in the processing of lignocellulosic biomass, and/or its components, for the purpose of producing renewable and value-added biomaterials. An understanding of how solvation can be achieved and the way in which the feedstock biopolymers are affected, however, needs to be gained prior to a viable implementation. In this thesis, the solvation of the wood biopolymers cellulose, xylan and lignin in the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate (EMIMAc) in a novel combination with the second system component 1-methylimidazole (MIM) have been investigated:The solvation of dissolving pulp, beech xylan and LignoBoost lignin model materials, was studied using FBRM (focused beam reflectance measurements) particle characterization in combination with microscopic analysis (cellulose and xylan), determination of molecular weights (xylan and lignin) and 13C- and 31P-NMR (nuclear magnetic resonance spectroscopy) of lignin.It was concluded that the most efficient solvation of cellulose and xylan occurred using 3-4% and 9% IL (n/n anhydroglucose units and n/n anhydroxylose Units), respectively, while polymer integrity was maintained. Cellulose solvation was found to be greatly dependent on the IL to AGU ratio whereas xylan solvation varied greatly with temperature. Moreover, a theoretical model was developed for the solvation of cellulose in the present system. The solvation of lignin was achieved at ~20% lignin loading (w/w), in any combination of MIM/EMIMAc. Regeneration of lignin resulted in two sets of fractions; one exhibiting a general and higher apparent molecular weight (Mw) along with an enrichment of condensed/aliphatic ether linkages and aliphatic hydroxyls, and the other exhibiting a lower apparent Mw and an enrichment of carboxylic and phenolic groups. The knowledge of biopolymer solvation gained in the present solvent system provides future opportunities of tuning extraction and/or fractionation processes to suite the specifications of a particular biomass-derived product.
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| 9. |
- Felix, J., et al.
(författare)
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P-61: Recycling and re-use of LCD components and materials
- 2010
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Ingår i: Digest of Technical Papers - SID International Symposium. - : Wiley. - 2168-0159 .- 0097-966X. ; 41, s. 1469-1472
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Konferensbidrag (refereegranskat)abstract
- Methods for extracting components and materials from waste liquid crystal displays have been developed. The methods enable the components to be extracted with their key properties preserved, thus qualifying them for re-use both in LCD and other applications. Novel applications for re-use of recycled LCD components have been developed in which the LCD components contribute with a substantial customer benefit.
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| 10. |
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European Energy Pathways - Pathways to sustainable european energy systems
- 2011
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Samlingsverk (redaktörskap) (refereegranskat)abstract
- To meet the challenge of climate change, the world must substaintially reduce emissions of greenhouse gases (GHGs). this must be accomplished in a way that maintains security of supply and competitiveness.This book presents to pathways towards sustainable European energy systems - the "Policy Pathway" and the "Market Pathway". These to pathways differ with respect to where the main responsability lies for transforming the energy system in following the pathway. The Policy pathway takes its departure from the EU Energy and Climate Package, and has a strong focus on targeted policies that promote energy efficiency and energy from renewable sources. The Market Pathway relies more on the market to transform the energy system, and presents a future in which the cost associated with emitting CO2 (and other GHGs) is the dominating policy measure.This book describes the research that has been carried out during the first period (2006-2010) of the AGS project "Pathways to Sustsainable Energy Systems". This interdisciplinary project involved more than 40 researchers and addressed various aspects of the challenges faced in transforming the European energy system. The chapters in this book cover more than 30 topics and presents an overall picture of the results obtained to date from various activities in the Pathways project.
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