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The primary objective of this study was to evaluate the qualities of Miscanthus pellets blended with pine sawdust at various ratios (Miscanthus/pine sawdust-0:100, 25:75, 50:50, 75:25, and 100:0) and relate them to energy generation potential under typical production conditions of the widely used bioenergy production technologies according to literature. Samples of each material were milled to the required sizes and blended in the proportions mentioned above. Water was added (6%) to each mixture to achieve a uniform moisture content of 10% on wet basis. The mixtures were then subjected to pressure agglomeration in the form of mechanical compression using a single pellet press so that homogeneously sized fuel pellets were obtained. Thereafter, the pure and blended pellet samples were examined using a range of analytical techniques to reveal any alterations in characteristics important to the utilization of the pellets as a green energy source. The results showed that, although temperature variations generally caused an estimated 6% moisture loss on a wet basis during pelleting with positive influence on the features of the pellets, the quality of the pellets in terms of ash composition (2-4%), hardness (41-46 kg/pellet), and heating value (20-21 MJ/kg) was in general more desirable for the blended pellets than for pure Miscanthus pellet. Structural analysis also revealed low levels of hydrophobic groups in the blends relative to pure Miscanthus, which were consistent with the fractions of pine sawdust and were also the reason for the pellets' increased hardness.

The primary objective of this study was to evaluate the qualities of Miscanthus pellets blended with pine sawdust at various ratios (Miscanthus/pine sawdust—0:100, 25:75, 50:50, 75:25, and 100:0) and relate them to energy generation potential under typical production conditions of the widely used bioenergy production technologies according to literature. Samples of each material were milled to the required sizes and blended in the proportions mentioned above. Water was added (6%) to each mixture to achieve a uniform moisture content of 10% on wet basis. The mixtures were then subjected to pressure agglomeration in the form of mechanical compression using a single pellet press so that homogeneously sized fuel pellets were obtained. Thereafter, the pure and blended pellet samples were examined using a range of analytical techniques to reveal any alterations in characteristics important to the utilization of the pellets as a green energy source. The results showed that, although temperature variations generally caused an estimated 6% moisture loss on a wet basis during pelleting with positive influence on the features of the pellets, the quality of the pellets in terms of ash composition (2–4%), hardness (41–46 kg/pellet), and heating value (20–21 MJ/kg) was in general more desirable for the blended pellets than for pure Miscanthus pellet. Structural analysis also revealed low levels of hydrophobic groups in the blends relative to pure Miscanthus, which were consistent with the fractions of pine sawdust and were also the reason for the pellets’ increased hardness., CC BY 4.0 License

This work investigates the proportion of generated fines in a pilot-scale experiment using a belt conveyor and commercial fuel pellets. For this, a belt conveyor with a length of 3.1 m was used and operated at varying conditions: speeds, percentages of material loading on the belt, two combinations of the inclination angle of the belt and the falling height, and a different number of handling steps. We considered a design of experiments approach based on response surface methodology to investigate the effect of different conditions on the potential of fines generation. Moreover, a comparison between the results of the belt conveyor and three common benchmark experimental approaches (tumbling box, rotary impact tester, and mechanical compression test) was made. Results show that the number of handling steps and the combined effect of drop height and inclination angle directly affected the fines generation. However, the tested belt speed range and the level of loading were of lower significance. A polynomial quadratic model was derived based on the regression analysis and showed a high accuracy to predict the proportion of fines. Moreover, the tumbling box method showed good potential to predict the proportion of fines in a belt conveyor when transported several times., Large Scale Energy Storage, Transport Engineering and Logistics

Detta arbete utvärderar bränslepellets ekonomiskt och arbetsmässigt gentemot andra konkurrerande uppvärmningssätt vilket i främsta hand är värmepumps-tekniken. Resultatet av studien visade att bränslepellets inte gav samma nöjdhet som värmepumpstekniken, rent ekonomiskt så var det värmepumpsteknik som var det mest driftekonomiska alternativet. Elpriser och effektdebitering gör att bränsle pelletsen i framtiden förmodas bli ett fördelaktigt val av värmekälla.

There are many factors that affect the quality of wooden fuel pellets, from raw materials to pellet production process. Among the factors, raw materials compositions, mechanical durability, moisture contents, and particle size distribution were studied. Experimental raw materials of different percent weights were introduced to industrial fuel pellet production, micro-chips in part-1 experiment and peat in part-2 experiment. Pellets made from these experimental raw material mixtures were tested for their mechanical strength (also known as durability) according to Swedish standards SS 187180 in Part 1 experiment, and European Technical Specification CEN/TS 15210-1 in Part 2 Experiment. Moisture contents of these pellets were also determined. In part-1 experiment, particle size distributions of raw materials and final micro- chips pellets were analyzed. Mapping of pellet production process, bio-energy combine power and heating plant integrated with pellet production were illustrated along with descriptions on major processes. Selected process parameters (i.e. feed rate, drying temperature, milling temperature, pellet machine temperature) for Part 2 experiment were extracted from an industrial program, PGIM signal explorer, and combine with experiment results, thereafter analyzed with statistical methods and by use of SIMCA-P program. The results show that more fresh chips in raw material mixtures give better mechanical strength for micro-chips pellets. For pellets with 80% fresh chips and 20% mature chips in raw materials composition, high durability came from low drying temperature and low feed rate. For peat pellets with 20% peat and 80% fresh chips in raw materials composition, high durability came from high drying temperature, high feed rate, relatively higher pellet moisture content and slightly lower pellet machine temperature. The high and low are relative and based on the experiment results., Validerat; 20101217 (root)

Biomass is considered to be a sustainable energy source with significant potentials for replacing electricity and fossil fuels, not at least in the residential sector. However, present wood combustion is a major source of ambient concentrations of hydrocarbons (e.g. VOC and PAH) and particulate matter (PM) and exposure to these pollutants have been associated with adverse health effects. Increased focus on combustion related particulate emissions has been seen concerning the formation, characteristics and implications to human health. Upgraded biomass fuels (e.g. pellets) provide possibilities of more controlled and optimized combustion with less emission of products of incomplete combustion (PIC´s). For air quality and health impact assessments, regulatory standards and evaluations concerning residential biomass combustion, there is still a need for detailed emission characterization and quantification when using different fuels and combustion techniques. This thesis summarizes the results from seven different papers. The overall objective was to carefully and systematically study the emissions from residential biomass combustion with respect to: i) experimental characterization and quantification, ii) influences of fuel, appliance and operational variables and iii) aspects of ash and trace element transformations and aerosol formation. Special concern in the work was on sampling, quantification and characterization of particulate emissions using different appliances, fuels and operating procedures. An initial review of health effects showed epidemiological evidence of potential adverse effect from wood smoke exposure. A robust whole flow dilution sampling set-up for residential biomass appliances was then designed, constructed and evaluated, and subsequently used in the following emission studies. Extensive quantifications and characterizations of particulate and gases emissions were performed for residential wood and pellet appliances. Emission factor ranges for

One of the great challenges facing society is to convert theglobal energy system to a sustainable process. Currently, 80%of the world´s energy is supplied through the combustionof fossil fuels. Not only are the fossil resources limited, theutilisation also increases the level of greenhouse gases in theatmosphere. The convertion to a sustainable energy system isproblematic since the technology needed to exploit mostnon-fossil energy sources is not yet fully developed, e.g.solar energy. Biofuel is an available renewable energy sourcewhich is already widely used in many countries. If an effectiveswitch-over from fossil fuels to biofuels is to be realised,biofuels must be viewed as a limited resource. Consequently, itis important that the handling, upgrading and utilisationprocesses involving biofuels are efficient so that itspotential can be fully exploited. This thesis considers efficient biofuel utilisation andupgrading within the sawmill industry. The goal has been toanalyse not only the technical opportunities for energy savingsin the sawmill industry, but also to analyse the costeffectiveness and environmental impact of studied measures. Theheat demand of the sawmill industry is almost completelycovered by its own by-products; primarily bark, sawdust andwood chips. The increased demand and improved economic value ofwoody biofuels on the market is thus an incentive for thesawmill industry to place more focus on energy issues. Thesawmill industry also has a more or less constant heat loadover the year, which is a beneficial factor for integrationwith district heating networks, biofuel upgrading plants andcombined heat and power plants. The conclusion of the study is that a variety of energyproducts such as heat, unrefined biofuel, pellets andelectricity can be efficiently produced in the sawmill industryand sold for profit to external customers. The payback periodsfor the proposed investments are moderate and both theemissions of volatile organic compounds and globa

Ash related problems have more than occasionally been observed in pellet burners during the last years. These problems can lead to reduced accessibility of the combustion systems as well as bad publicity for the market. The objectives of the present work were to; (i) evaluate how different raw materials for pellets affect the accessibility of the existing burner equipment, (ii) determine which of the ash forming element(s) that could be responsible for the deposit/slagg formation and, (iii) estimate the critical slagging temperature for the different raw materials. Stored and fresh materials from sawdust, logging residues and bark were used as raw material in three different pellet burners. The results showed that the slagging properties were relatively sensitive to the variations in total ash content and ash forming elements of the fuel. It is therefore recommended that ash rich fuels like bark and logging residues should not be used in the existing residential pellet burners. Both fuel and burner type affected the amounts of ash deposit produced. The degree of sintering (i.e. the strength of the deposits) was mostly affected by the fuel composition. Subsequent controlled sintering test of the produced deposits/slags showed critical slagging temperatures of about 850–900 °C for stored bark and about 1000 °C for fresh bark and stored and fresh materials from sawdust and logging residues. The results further indicated that the Si-content in the fuel correlated (relatively) well to the sintering tendencies in the burners. Chemical equilibrium models were used to interpret the experimental findings, and good quantitative agreements between modelling and experimental results were generally obtained.

The increased concentration of greenhouse gases in theatmosphere, in particular CO2, is changing the Earth’s climate. Accordingto the Kyoto protocol, where the international community agreedon binding emission targets, developed countries are committedto reduce their greenhouse gas emissions. The increased use ofbiomass in energy systems is an important strategy to reduce CO2emissions. The purpose of this thesis has been toanalyse the opportunities for Sweden to further reduce CO2emissions in the energy system, by rationallyutilising woody biomass energy. The characteristics of currentcommercially operating biofuel-based CHP plants in Sweden aresurveyed and systematically presented. A consistent andtransparent comprehensive reference base for system comparisonsis given. Furthermore, the fuel effectiveness and contributionto CO2reduction is calculated. The governmentalsubsidies of the CHP plants’investment, expressed as costof specific CO2reduction, appears to be low. The competitiveness of biomass-fuelled energy production inrelation to fossil-based production with carbon capture isanalysed, showing that the biomass-fuelled systems provide acompetitive option, in terms of cost of electricity andefficiencies. The remaining Swedish woody biofuel potential ofat least 100 PJ/yr is principally available in regions with abiomass surplus. Transportation is therefore required to enableits utilisation in a further national and international market.Refining the biofuel feedstock to pellets, or even furtherrefining to motor fuels (DME, methanol or ethanol) or power,could facilitate this transport. Different options for fuelrefining are studied and compared. The entire fuel chain, fromfuel feedstock to end users, is considered and CO2emissions are quantified. Substituting fuelpellets for coal appears to be the most costeffectivealternative and shows the largest CO2reduction per energy unit biofuel. Motor fuelsappear more costly and give about half the CO2reduction. Transportati, NR 20140805

A summary of the DR3 reactor and HP1 rig design is given followed by a detailed description of the calculation procedure for obtaining linear heat rating and burn-up values of fuel pins irradiated in HP1 rigs. The calculations are carried out rather detailed, especially regarding features like end pellet contribution to power as a function of burn-up, gamma heat contributions, and evaluation of local values of heat rating and burn-up. Included in the report is also a description of the fast flux- and cladding temperature calculation techniques currently used. A good agreement between measured and calculated local burn-up values is found. This gives confidence to the detailed treatmant of the data.

A versatile extrusion-type pneumatic gun is described. The extrusion nozzle/gun barrel system can easily be exchanged to produce pellets in the diameter range 0.4—2.0 mm. Velocities in the range 0.1—1.35 km/s are obtained by adjusting the propeller gas pressure. It is proposed that this gun type can be used for larger pellets of 3.2 mm diameter as well and to accelerate such pellets by means of a high-pressure discharge.

Bakalářská práce je zaměřena na problematiku jaderného paliva určeného pro jaderné reaktory. Věnuje se rešerši současných trendů jaderných pelet. Jsou zde popsány kvalitativní parametry jaderných paliv, převážně však tepelná vodivost a hustota jaderného paliva. Zvláštní kapitola je věnována simulaci příměsi paliva a jeho průběhu vyhořívání. Závěrečná část bakalářské práce je věnována konkrétnímu návrhu materiálu pro testovací výzkumnou peletu., The bachelor thesis is focused on the issue of nuclear fuel used for nuclear reactors. It is dedicated to research of current trends in nuclear pellets. The qualitative parameters of nuclear fuels are described here, predominanly thermal conductivity and density of nuclear fuel. A special chaper of this thesis is devoted to the simulation and fuel additives during burnout. The final part of the bachelor thesis is dedicated to a specific design of material for a test research pellet.

Bakalářská práce je zaměřena na problematiku jaderného paliva určeného pro jaderné reaktory. Věnuje se rešerši současných trendů jaderných pelet. Jsou zde popsány kvalitativní parametry jaderných paliv, převážně však tepelná vodivost a hustota jaderného paliva. Zvláštní kapitola je věnována simulaci příměsi paliva a jeho průběhu vyhořívání. Závěrečná část bakalářské práce je věnována konkrétnímu návrhu materiálu pro testovací výzkumnou peletu., The bachelor thesis is focused on the issue of nuclear fuel used for nuclear reactors. It is dedicated to research of current trends in nuclear pellets. The qualitative parameters of nuclear fuels are described here, predominanly thermal conductivity and density of nuclear fuel. A special chaper of this thesis is devoted to the simulation and fuel additives during burnout. The final part of the bachelor thesis is dedicated to a specific design of material for a test research pellet.

Bakalářská práce je zaměřena na problematiku jaderného paliva určeného pro jaderné reaktory. Věnuje se rešerši současných trendů jaderných pelet. Jsou zde popsány kvalitativní parametry jaderných paliv, převážně však tepelná vodivost a hustota jaderného paliva. Zvláštní kapitola je věnována simulaci příměsi paliva a jeho průběhu vyhořívání. Závěrečná část bakalářské práce je věnována konkrétnímu návrhu materiálu pro testovací výzkumnou peletu., The bachelor thesis is focused on the issue of nuclear fuel used for nuclear reactors. It is dedicated to research of current trends in nuclear pellets. The qualitative parameters of nuclear fuels are described here, predominanly thermal conductivity and density of nuclear fuel. A special chaper of this thesis is devoted to the simulation and fuel additives during burnout. The final part of the bachelor thesis is dedicated to a specific design of material for a test research pellet.