European Union’s (EU) dependence on fossil fuel imports strongly affects its energy supply and economic and national stability. In order to reduce its dependence and maintain the leadership position in GHG emissions reductions and renewable energy consumption, EU has set ambitious targets of reducing GHG emissions by at least 20% compared with 1990, raising the share of renewable energy to 20% and increasing the levels of biofuels in transport fuels to 10% by 2020. While some of the countries, due to their large renewable potential, have already reached set targets, some are still far behind. Biomass, with 69.8% share in gross inland consumption of renewables, has the greatest potential. Since some EU members have low availability of biomass, and are scarce in other renewable sources, they have become biomass importers. As some studies have shown, imports of biomass reduce cost of achieving targets for renewable electricity and increase electricity production from biomass. Wood pellets, as currently the most tradable solid biomass commodity, already reached significant shares in imports and consumption of biomass in some EU countries. The most of pellets were traditionally imported from Canada; however, last year US became the EU’s largest importing partner with 534,000 tons of industrial pellets exported mainly to Belgium and Netherlands. The EU’s increasing demand for wood pellets was a major driver for substantial increase in the wood pellet production capacity in US, with many plants being constructed for export to EU. This thesis evaluates the possibility of producing wood and switchgrass pellets in East Tennessee, assuming three feedstock scenarios, and their export to EU. Results from the base-case model showed that production costs of pellets were $155, $164 and $170 per ton, while price of pellets on the EU market will have to be $207, $216 and $222 per ton in the 100% mill residue, 40/60 blend and 100% switchgrass scenarios, respectively, for the project to breakeven. Sensitivity analysis showed a strong impact of feedstock price, moisture and exchange ratio on project’s return on investment.

The aims of the work this thesis is based upon were to develop convenient analytical procedures for determining resin acids in biological and environmental matrices, and apply them to enhance understanding of the occurrence, exposure to and uptake by exposed individuals of resin acids. Particular focus has been on the workplace environment of the Swedish wood pellets industry. Sample extraction procedures and high-performance liquid chromatography/electrospray ionisation-mass spectrometry (HPLC/ESI-MS) methodologies were developed for measuring resin acids in dust, skin and urine samples. Chromatographic separation of abietic (AA) and pimaric acid was achieved by using a polar-embedded C12 stationary phase. The HPLC/ESI-MS method avoids undesirable oxidation of AA, which was found to occur during the derivatisation step in the standard MDHS 83/2 gas chromatography/flame ionisation detection (GC/FID) methodology, leading to false observations of both AA and the oxidation product 7-oxodehydroabietic acid (7-OXO). Personal exposures to resin acids in the Swedish wood pellet production industry were found to be lower, on average, than the British Occupational Exposure Limit for rosin (50 µg/m3). The oxidised resin acid 7-OXO, was detected in both dust and skin samples indicating the presence of allergenic resin acids. A correlation between air and post-shift urinary concentrations of dehydroabietic acid (DHAA), and a trend towards an increase in urinary 7-OXO during work shifts, were also observed. Whether the increase in 7-OXO was due to direct uptake or metabolism of other resin acids cannot be concluded from the results. An efficient HPLC/UV methodology with diode-array detection was developed for screening commercial products for rosin that could be used in laboratories lacking mass spectrometers. Very high concentrations of free resin acids were detected in depilatory wax strips using the method. / At the time of doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Submitted.

Diss. Västerås : Mälardalens högskola, 2006.

Com os planos de descarbonização de diversos países do mundo, o contínuo crescimento do mercado mundial dos pellets de madeira tende a aumentar, e para atender a demanda será necessário à inclusão de países emergentes dos quais revelam potencial o Brasil, dado que possui grande vocação na produção sustentável de florestas para produção de madeira do gênero Eucalyptus ssp., que apresenta produtividade entre 30% a 50% superior a qualquer pais do mundo, tornando-se a espécie ideal para produção em escala de biomassa para energia. O problema central consiste em viabilizar a produção sustentável de pellets de madeira, que possam atender a demanda nacional e internacional. Contudo este estudo inicialmente identificou a oferta e demanda de madeira para energia por tipo e fonte, posteriormente foram levantados os potenciais produtivos de florestas energéticas de curta rotação, para atender a iminente demanda nacional e internacional de madeira para energia, e finalmente foram detectados os problemas presentes na biomassa sólida vegetal do gênero Eucalyptus ssp., no Brasil. Como resultado este estudo mostra o potencial de produção sustentável de eucalipto de curtas rotação a 150 km dos portos brasileiros para produção e exportação de pellets, como também tem como resultado uma patente de invenção (BR 10 2016 023862 5) que resulta na extração a níveis aceitáveis pelas normas ENplus e semelhantes das emissões de cloro da madeira, e de metais alcalinos, fator limitante para o uso da biomassa na produção de pellets combustível. Evitando assim a formação de dioxinas, e organoclorados que prejudicam a saúde humana e propiciando também redução da formação de cinzas, diminuindo a corrosão dos equipamentos de combustão para produção de energia através de biocombustíveis sólidos. / The decarbonization plans worldwide, the world market of wood pellets tends to increase, and to meet the world demand it will be necessary to include emerging countries which show potential such as Brazil, as it has a great vocation in sustainable production of Eucalyptus wood and has higher productivity than any other country in the world, it is the ideal forest species for wood pellets production for energy in Brazil. The central problem is to enable the sustainable production, which can meet domestic and international demand of woody biomass for energy. This study initially identified the wood supply and demand for energy by type and source, and it was later raised to the productive potential of energy forests; finally it was detected the problems in solid biomass in Brazil. Results of this study show the sustainable production potential of short rotation Eucalyptus in range of (150 km) of Brazilian ports, aiming to pellets export, as well as this study has resulted in a patent, number: (BR 10 2016 023862 5), resulting in reduced to acceptable levels (ENplus), by the relevant rules of chlorine emissions, thus preventing the formation of dioxins, and allowing removal of alkali metals thereby reducing the formation of ash and decreasing the corrosion of combustion systems for energy production by solid biofuels.

Com os planos de descarbonização de diversos países do mundo, o contínuo crescimento do mercado mundial dos pellets de madeira tende a aumentar, e para atender a demanda será necessário à inclusão de países emergentes dos quais revelam potencial o Brasil, dado que possui grande vocação na produção sustentável de florestas para produção de madeira do gênero Eucalyptus ssp., que apresenta produtividade entre 30% a 50% superior a qualquer pais do mundo, tornando-se a espécie ideal para produção em escala de biomassa para energia. O problema central consiste em viabilizar a produção sustentável de pellets de madeira, que possam atender a demanda nacional e internacional. Contudo este estudo inicialmente identificou a oferta e demanda de madeira para energia por tipo e fonte, posteriormente foram levantados os potenciais produtivos de florestas energéticas de curta rotação, para atender a iminente demanda nacional e internacional de madeira para energia, e finalmente foram detectados os problemas presentes na biomassa sólida vegetal do gênero Eucalyptus ssp., no Brasil. Como resultado este estudo mostra o potencial de produção sustentável de eucalipto de curtas rotação a 150 km dos portos brasileiros para produção e exportação de pellets, como também tem como resultado uma patente de invenção (BR 10 2016 023862 5) que resulta na extração a níveis aceitáveis pelas normas ENplus e semelhantes das emissões de cloro da madeira, e de metais alcalinos, fator limitante para o uso da biomassa na produção de pellets combustível. Evitando assim a formação de dioxinas, e organoclorados que prejudicam a saúde humana e propiciando também redução da formação de cinzas, diminuindo a corrosão dos equipamentos de combustão para produção de energia através de biocombustíveis sólidos. / The decarbonization plans worldwide, the world market of wood pellets tends to increase, and to meet the world demand it will be necessary to include emerging countries which show potential such as Brazil, as it has a great vocation in sustainable production of Eucalyptus wood and has higher productivity than any other country in the world, it is the ideal forest species for wood pellets production for energy in Brazil. The central problem is to enable the sustainable production, which can meet domestic and international demand of woody biomass for energy. This study initially identified the wood supply and demand for energy by type and source, and it was later raised to the productive potential of energy forests; finally it was detected the problems in solid biomass in Brazil. Results of this study show the sustainable production potential of short rotation Eucalyptus in range of (150 km) of Brazilian ports, aiming to pellets export, as well as this study has resulted in a patent, number: (BR 10 2016 023862 5), resulting in reduced to acceptable levels (ENplus), by the relevant rules of chlorine emissions, thus preventing the formation of dioxins, and allowing removal of alkali metals thereby reducing the formation of ash and decreasing the corrosion of combustion systems for energy production by solid biofuels.

Invasive species exact important ecologic, economic, and cultural tolls in forests. This research focused on the intersections of invasive ecology, forest management, and a forest commodity. Invasive ecology was explored through an assessment of two potential biological control agents of hemlock woolly adelgid. The two species of silver fly (Leucopis spp.) from the Pacific Northwest were first examined for temporal resource partitioning patterns. The niches of these species were then examined spatially by developing a species distribution model. Leucopis spp. exhibited sinusoidal patterns of daily emergence when examined over a 29-day period, with peak daily abundances that were inversely related. Spatially, however, landscape-scale and climatic indicators were not significant in predicting the presence of Leucopis spp. in the Pacific Northwest. This adds important information about niche dynamics of Leucopis spp. in the Pacific Northwest, which may have logistical and operational implications for their use in the USDA Forest Service’s Hemlock Woolly Adelgid Initiative. Additionally, the potential opportunities and risks of using wood that has been impacted by invasive species and pests was explored through a literature analysis focused on three species posing a threat to northeastern US forests: emerald ash borer, hemlock woolly adelgid, and southern pine beetle. Based on this review, I concluded that although opportunities for the use of this wood are sometimes recognized, the phytosanitary risks in feedstock pre-treatment are not being directly addressed in US-related literature. These studies provide important evidence for adaptive solutions to forest pests that consider both forest health and forest economics.

Yes / This study investigates the physical and mechanical properties of 12 biomass wood pellet samples utilised in a power generation, focusing on their implications for energy release and carbon emissions during combustion. Through comprehensive analysis involving bulk density measurements, compression tests, moisture analysis, calorimetry and controlled burning experiments, significant correlations among key properties are identified. Pellets with densities above 1100 kg/m3 demonstrate superior mechanical durability and strength, achieving maximum strengths of 0.6 to 0.8 kN with durability exceeding 99.4%. Optimal moisture content, typically between 6 and 7% is crucial for maximising density, bulk density, mechanical durability and fracture resistance, ensuring robust pellet structure and performance. The research underscores the impact of pellet dimensions, highlighting those longer lengths, > 12 mm enhance durability, while larger diameters > 8 mm exhibit reduced durability. Elemental analysis focusing on calcium, silicon and potassium plays a critical role in predicting and managing combustion system fouling, potentially reducing operational costs. Moreover, the study emphasises the significant influence of oxygen levels during combustion on CO2 emissions, achieving optimal results with moisture content in the 7–8% range for maximum higher heating value (HHV). The moisture content in the 14–15% range represents the lowest CO2 emission. The findings underscore the intricacy of the system and the interplay of parameters with one another. In accordance with the priority of each application, the selection of parameters warrants careful consideration. / This work was supported by the UK Carbon Capture and Storage Research Community (UKCCSRC) and the Engineering and Physical Sciences Research Council (EPSRC) through the UKCCSRC Flexible Funding Call 2022.

Um bei der Herstellung der Holzpellets den Energieaufwand zu minimieren und gleichzeitig die Qualitätsanforderungen der DINplus zu erfüllen, werden häufig Presshilfsmittel beim Pelletieren eingesetzt, bisher vor allem Mais- und Weizenstärke. Um flexibler auf veränderte Markt- und Rohstoffbedingungen reagieren zu können, besteht von Seiten der Hersteller Bedarf an alternativen Presshilfsmitteln. Allerdings ist deren Einfluss auf das Verbrennungs-, Emissions- und Ascheerweichungsverhalten nur unzureichend erforscht. Im Rahmen eines Forschungsprojektes zur Optimierung der Pelletproduktion wurden in dieser Diplomarbeit Versuche durchgeführt, um den Einfluss verschiedener natürlicher Presshilfsmittel, der Pelletqualität (Feinanteil, Stückigkeit) und der Feuerungsart (Unterschub- und Abwurffeuerung mit Brennerschale) auf das Emissionsverhalten (Kohlenmonoxid-, Stickoxid-, Gesamtkohlenstoff und Staubgehalt im Abgas), den Anlagenbetrieb (Brennstoffförderraten, Abgasverluste, Luftüberschuss) und das Ascheerweichungsverhalten beim Betrieb von zwei Kleinfeuerungsanlagen mit DINplus-konformen Holzpellets, zu untersuchen.

Trichoderma atroviride SC1 (SC1) was isolated from hazelnut wood and it is effective in the biocontrol of soil-borne pathogens. However, its effectiveness decreases as its population declines in the soil over time. To improve its persistency in the soil, lignocellulosic materials (wood pellets) were tested to be used as carriers to sustain the population of SC1 and facilitate its incorporation into the soil. A method was developed to coat wood pellets of fir, beech, and chestnut with a conidial suspension to reach a preset concentration (i.e. 10^4, 10^5, and 10^6 cfu/ g of wood). The growth of SC1 on each type of wood was compared. Chestnut pellets were excluded from further experiments because they had low counts of colony-forming units (cfu) of SC1. Beech pellets were preferred over fir pellets for showing more suitable physicochemical characteristics for soil application. In addition, for the same wood type, increased initial coating concentrations did not impact the final colony counts of SC1 and no significant difference was observed between the counts of 10^4, 10^5, and 10^6 cfu/g of wood at the end of the experiment. The addition of small quantities of nitrogen increased the final cfu on all types of wood pellets. The growth of SC1 on beech pellets was then tested by adding cheap nitrogen sources namely, soy flour, soy protein isolates, and proteins that originated from animal wastes. The best results were obtained with soy protein isolates (1 g/L) and the population of SC1 reached 10^9 cfu/ g of beech wood. Finally, this carrier of coated beech pellets with soy protein isolates was tested in the soil under controlled conditions, in an experimental greenhouse at 25°C and 60% of soil humidity. The pellets were coated to reach a final concentration of 5×10^5 cfu/ g of beech and 10 g of beech coated pellets were mixed with 1 kg of soil in plastic pots to reach the final concentration of 5×10^3 cfu/ g of soil. The carrier increased the bacterial richness and diversity of the soil and decreased the fungal ones. The total Trichoderma population persisted in the first month and then declined after three months with competition from other bacteria such as Massilia spp. and fungi such as Stachybotrys spp. and Mortierella spp.

This thesis project investigates the granular flow of wood pellets inside a pilot-scale rotary kiln and its impact on the pyrolysis process. The study focuses on two key factors that must be determined to evaluate their effects on pyrolysis: the mass flow rate delivered by the feeding system at different motor frequencies and the mean residence time (MRT) of the wood pellets. The research is divided into two parts: the first characterizes granular flow without heat application, while the second examines the system behavior under high-temperature pyrolysis conditions. For the first part, the mass flow rate was assessed by measuring the emptying time of the feeding silo at different screw velocities. In contrast, the MRT was determinedwith two scenarios: (1) batches of different masses of wood pellets and (2) continuousfeed until a stable solid bed was formed that allowed tracer particle tracking. In the second part of the study, the drum’s rotational speed and fed mass flow rate were varied. Results indicated a direct proportionality between the mass flow rate delivered by the feeding systems and the screw motor frequency. Additionally, the MRT was found to follow an inverse relation with the drum’s rotational speed if the process was done in batches. In contrast, the MRT was 20 minutes at a feeding rate of 51 kg h-1 and a drum’s rotational speed of 0.36 rad s -1 with a continuous feeding process. Finally, the study concludes that the wood pellet feed rate and drum rotational speed significantly influence the pyrolysis process in the rotary kiln. The system remained stable for wood pellets inside the rotary drum, starting with a feeding rate of 8 kg h-1 and scaling up until a maximum of 21 kg h-1. This behavior is evidenced by the direct proportionality between the evolution of flue gas and pyrolysis gas temperatures over time and the necessity to adjust air supply to maintain system stability.