No contexto mundial atual, a busca de fontes de energia renováveis e menos poluentes que o petróleo tornou-se inevitável. O uso da biomassa como fonte de energia é extremamente importante, devido principalmente ao seu caráter renovável e a sua abundância. Os resíduos florestais são cada vez mais preconizados como uma importante fonte de biomassa. Isto se deve a sua abundância, facilidade de aprovisionamento e baixo custo. Podemos citar, como exemplo, os resíduos gerados durante a colheita florestal (cascas, folhas, galhos, ponteiros, entre outros) e durante o processamento mecânico da madeira (costaneiras, aparas, pó de serra, entre outros). O uso deste tipo de material para fins energéticos vem crescendo, porém, há um grande espaço para melhorias a serem implementadas nesse campo, envolvendo o melhor conhecimento de suas características e o potencial de aplicação de processos para sua conversão em produtos mais otimizados em relação aos seus valores energéticos. Diante desse quadro, e em se considerando a madeira, surge a oportunidade para adoção de processos de tratamento térmico, para os quais já existem referências que indicam a ocorrência de mudanças nas características desse material, o que conduz à previsão de se poder obter resultados positivos em relação ao que se exige para usos energéticos. Além do tradicional e amplamente usado processo de secagem, constatase, no campo do tratamento térmico, o crescimento do interesse pela aplicação da chamada torrefação e da termorretificação, compreendendo faixas de temperatura entre 150 e 300 °C. Neste contexto, resíduos da colheita florestal de eucalipto e pinus foram submetidos a tratamento térmico conduzido em estufa elétrica laboratorial, numa faixa de temperatura entre 140 e 300 °C. O objetivo foi estudar as alterações que o tratamento pudesse proporcionar às características do material, no sentido de se potencializar ainda mais o seu uso para fins energéticos, mediante a avaliação da densidade a granel do material, tamanho das partículas dos resíduos, poder calorífico superior, índice de combustão, análise imediata, resistência à moagem (redução granulométrica) e avaliação de imagens microscópicas. Os resultados indicaram, para ambas as espécies, que o aquecimento exerceu influência significativa nos rendimentos mássicos e nas características dos ensaios acima citados, com alteração dos valores com a elevação da temperatura, exceto para o teor de cinzas do eucalipto. A influência exercida pelo tratamento térmico foi mais evidente a partir de 220 °C, sendo isto mais fortemente observado à temperatura de 300 °C, com a constatação da maior fragmentação dos materiais tratados em comparação ao material testemunha. Além do aumento da friabilidade dos materiais estudados, constatado pelo ensaio de resistência à moagem, onde houve um relevante aumento da quantidade de material de baixa granulometria (menor que 4 mm), os mesmos apresentaram um maior ganho energético (maior poder calorífico) levando-se em conta a testemunha, principalmente a 300 °C, com índices de combustão elevados para os resíduos de eucalipto e pinus. / In the current worldwide context, the search for renewable energy sources and less polluting fuels than petroleum has become unavoidable. The use of biomass energy as source of energy is extremely important, especially due to its renewable character and abundance. The forest residues have been increasingly recommended as an important source of biomass. This is due to its abundance, facility of provision and low cost. We can cite examples such as the residues generated during the forest harvest (bark, leaves, branches, stem tips, among others) and during the mechanical processing of wood (slabs, chips, sawdust, among others). The use of this kind of material for energetic purposes has been increasing, however, there is room for benefits to be implemented in this field, involving a deeper knowledge on its characteristics and the potential for the application of processes to its conversion into more optimized products in relation to its energy values. In this scenario, and considering the wood, there comes the opportunity to the adoption of thermal treatment processes, to which there are already references that indicate the occurrence of changes in the characteristics of this material, which leads to the prediction of the possibility to obtain positive results in relation to what is demanded for energetic uses. Besides the traditional and widely used process of drying, it is observed, in the field of thermal treatment, the increase in the interest for the application of the so-called torrefaction and thermal rectification, comprising zones of temperature between 150 and 300 °C. In this context, residues of eucalyptus and pine forest harvest were submitted to a thermal treatment conducted in an electric laboratory oven, at temperatures between 140 and 300 °C. The goal was to study the alterations that the treatment might provide to the characteristics of the material, aiming at empowering its use to energetic purposes, through the density evaluation of a sample of the material, the size of residue particles, gross calorific value, combustion index, immediate analysis, resistance to grinding (particle size reduction) and the evaluation of microscopic images. The results indicated, for both species, that the heating caused a significant influence on the gravimetric yields and on the characteristics of the experiments cited above with changes in the values with the increase of the temperature, except for the ash content of eucalyptus. The effect of the thermal treatment was more evident from 220 °C, which is more strongly observed at the temperature of 300 °C, with a larger fragmentation of the treated materials in comparison to the control material. Besides the increase in the friability of the studied materials, found in the experiment of resistance to grinding, in which there was a relevant increase in the amount of low granulometry material (smaller than 4 mm), they presented a higher energetic gain (more calorific value) considering the witness, mainly at 300 °C, with high combustion indexes for the eucalyptus and pine residues.

Thesis (Master of Engineering in Electrical Engineering)--Cape Peninsula University of Technology, 2018. / In Sub-Saharan Africa (SSA), there are several challenges that hinder development. One of these challenges is access to electricity. There are numerous benefits to having access to reliable electricity. These include less time spent fetching water from rivers and dams, as water purification systems for households could be used in villages; children in villages would be able to spend more time doing their schoolwork and not fetching wood for fire; and automated irrigation systems could be used for villagers to farm and make an income. Finding alternative ways to generate electricity would enable access to electricity for regions that currently do not have the electricity. This means that large organisations need to find alternative ways of generating electricity, as they have the means to do so. With the current renewable energy technologies available, there are now more ways in which electricity could be generated. The use of biomass is no exception to this. With constant developments in the renewable energy sector, waste-to-energy (WtE) is proving to be a viable method to generate electricity. The main aim of this research was to determine if a commercial food retailing organisation could use their food waste for generating electricity for their own use to reduce their demand from the central grid. A way of determining the viability of this type of technology is using a software that simulates renewable energy projects. In this research, an organisation was contacted for waste data. Systems for two of the stores will be simulated and results will be discussed. The organisation will remain anonymous. The software used in this research is System Advisor Model (SAM), which was developed by the National Renewable Energy Laboratory (NREL) in the United States. In the results, three results were discussed. These are the monthly energy, monthly heat rate and the monthly boiler efficiency for each of the stores for Store 1, the annual energy simulated was 138,509 kWh and 131,677 kWh for Store 2. Monthly energy averages for each store were 11,542 kWh for Store 1 and 10,973 kWh for Store 2, respectively. There are several opportunities for research based on the findings. These include researching other food sectors in the study; conducting a financial analysis of small-scale WtE systems; constructing a prototype of the system; and using three different softwares to simulate a system for the same project.

Orientador: Fernando Masarin / Banca: Michel Brienzo / Banca: Valéria de Carvalho Santos Ebinuma / Resumo: A macroalga vermelha Kappaphycus alvarezii é rica em carboidratos, porém contém outras frações constituídas de proteínas, inorgânicos e aromáticos. O presente trabalho foi justificado devido ao fato de que o resíduo gerado no processamento de carragena semi-refinada ser menos recalcitrante comparado a resíduos lignocelulósicos. Objetivo: Avaliar o potencial da conversão enzimática das frações geradas no processamento de carragena oriundo da macroalga Kappaphycus alvarezii em açúcares monoméricos fermentescíveis. Métodos: A parte experimental envolveu a obtenção de um resíduo a partir do processamento de carragena semi-refinada de K. alvarezii. A fração não tratada e as frações obtidas no processamento foram caracterizadas quimicamente e hidrolisadas enzimaticamente. Na hidrólise enzimática foram utilizados extratos enzimáticos comerciais e um extrato enzimático obtido a partir de Aspergillus sp. Resultados: O processamento de carragena semi-refinada e a obtenção do resíduo foram realizadas com sucesso. Os rendimentos globais de obtenção de carragena semi-refinada e do resíduo foram de 46,8% e 19,2%, respectivamente. As frações, não tratada, tratada com KOH, o resíduo e a carragena semi-refinada mostraram teores brutos de 44,8%, 41,5%, 32,7% e 53,6% (galactana), 12,4%, 13,4%, 38,4% e 8,3% (glucana), 15,8%, 14,9%, 8,6% e 18,2% (cinzas)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The red macroalgae Kappaphycus alvarezii is rich in carbohydrates, but contains other fractions constituted of proteins, inorganic and aromatics. The present study was justified due to the fact that the residue generated in the processing of semirefined carrageenan is less recalcitrant compared to lignocellulosic residues. Objective: Evaluate the potencial of the enzymatic conversion of the fractions generated in the carrageenan processing from macroalgae Kappaphycus alvarezii in fermentable monomeric sugars. Methods: The experimental part involved the obtaining of a residue from the processing of semirefined carrageenan of K. alvarezii. The untreated fraction and fractions obtained in the processing were chemically characterized and enzymatically hydrolyzed. In the enzymatic hydrolysis were used commercial enzymatic extracts and an enzymatic extract obtained from Aspergillus sp. Results: Processing of semirefined carrageenan and the recovery of the residue were carried out successfully. Overall yields of semirefined carrageenan and residue were 46.8% and 19.2%, respectively. The content of untreated fraction, treated with KOH, residue and semirefined carrageenan were 44.8%, 41.5%, 32.7% and 53.6% (galactan), 12.4%, 13.4%, 38.4% e 8.3% (glucan), 15.8%, 14.9%, 8.6% and 18.2% (ash) and 12.6%, 13.8%, 8.1% and 13.3% (sulfate groups), respectively. The fraction of the residue showed to be rich in glucan while the fraction of semirefined carrageenan rich in galactan and ashes. Commercial enzymatic extracts used were characterized and maximum values of specific activity of cellulases and galactanases were 1.3 FPU.mg-1 and 0.3 IU.mg-1, respectively. Extract obtained from Aspergillus sp. used characterized and maximum values of specific activity of β-galactosidase and galactanases... (Complete abstract click electronic access below) / Mestre

Lignin is an important component of biomass accounting for up to 30% by weight but up to 40% of the total energy content of the plant. As the push towards alternative fuels develops, more and more amounts of lignin will be gathered and used predominately as low grade boiler fuel to run primary processes. We argue there is usefulness in the conversion of lignin into value added specialty chemicals and fuels. In this work, a new approach for hydrodeoxygenation of lignin model compounds using platinum as the catalyst and organic solvent as the reaction medium was conducted, and the results were compared with those obtained using water as the reaction medium. It is shown that the organic solvent, with its increased hydrogen solubility, is able to hydrogenate the model compound with the same effect at lower temperature, hydrogen pressure, and time.

Lignin is the second most abundant biopolymer on Earth, right after cellulose, with a highly complex chemical structure that hinders its possible utilizations. Applications that utilize lignin in different manners are of great interest, due to its inexpensive nature. Present work is based on the notion of converting lignin into different biofuels that have only a few, however important, advantages over lignin as a direct energy source. The first part of current work (pyrolysis) details the analysis of lignin from a relatively new lignin isolation process called LignoBoost. It is obtained from the pulp and paper industry via CO₂ precipitation of lignin from black liquor (BL). This method is environment friendly, results lignin with minimal oxidation, eliminates the main bottleneck of the Kraft cycle (recovery boiler capacity), and yet leaves enough lignin in the process stream to recover pulping chemicals and generate energy for the pulp mill. Pyrolysis had converted this lignin into bio-oil with high aliphatic content and low oxidation level, all advantageous for application as liquid fuel. The second part of this dissertation proved the theory that lignin degradation and lipid accumulation metabolic pathways can be interconnected. Gram-positive Rhodococcus opacus species, DSM 1069 and PD630 were used to evaluate lignin to lipid bioconversion, starting with ethanol organosolv and Kraft lignin. This conversion is a first step in a multistep process towards biodiesel production, which includes transesterification, after lipids are extracted from the cells. Results clearly indicated that the lignin to lipid bioconversion pathway is viable, by cells gaining up to 4 % of their weight in lipids, while growing solely on lignin as a carbon and energy source.

Effective combustion of waste fuels requires an understanding of the fuels characteristics. Gaseous and particulate emissions, ash residues and combustion properties are of interest to many; those that produce and sell heating units, utilities interested in using the fuels for power generation, regulatory agencies, municipalities needing to solve a disposal problem, and environmentally conscious people interested in maximum utilization of resources. A study was conducted at Oregon State University to test and evaluate the use of two types of waste: mixed waste paper (MWP) and refuse derived fuel (RDF). Wood biomass (ponderosa pine) was used as a benchmark and also cofired with MWP. Samples collected from the Pacific Northwest were tested for physical, chemical, combustion, and emission characteristics. Raw fuel samples were tested for moisture content and bulk density. The samples were then shredded and pelletized. Pelletized fuels were tested for ultimate and proximate analyses, ash fusion temperature, elemental ash analysis, higher heating value, moisture content, bulk density, and pellet durability. Using an existing biomass combustion facility, the samples were fired to determine the optimum thermodynamic conversion combustion condition for each fuel. Observations were made of physical problems associated with firing of the samples. Combustion products were continuously monitored for temperature and composition with a combustion analyzer. An EPA Method 5 sampling train was used to determine particulate, heavy metals, chloride, fluoride, and sulfate emissions. Leachate testing was performed on the bottom ash residue to determine heavy metal concentrations. Waste fuels provided a challenge for combustion study in a biomass combustion unit. Modifications were required to alleviate high ash content problems. Observations of corrosion and clinkers provided another comparison for fuel evaluation. Comparison of emissions resulting from different fuel types provided good practical information for industrial purposes. Observed trends indicated possible minimization of emissions corresponding to optimum thermodynamic conversion. Cofiring analysis revealed possible increases and decreases of heavy metal emissions for MWP and wood. / Graduation date: 1992

The first part of the thesis presents a study based on the forest biorefinery concept, which involves converting a pulp mill into a multi-purpose biofuels, biomaterials, and biopower production facility in which these products are produced in an environmentally compatible and sustainable manner. A key challenge in this process is the recovery of lignin from process streams such that it can be utilized in a variety of innovative green chemistry processes The first study examines the fundamental chemical structure of LignoBoost derived lignin recovered from Kraft pulping streams using an acid precipitation/washing methodology. Functional group analysis and molecular weight profiles were determined by nuclear magnetic resonance (NMR) and size exclusion chromatography. These findings gave valuable insight into the physical properties and the determining chemical properties of this currently underutilized, renewable bioresource. The second study is based on the future second generation bioethanol production process, where ethanol produced from lignocellulosic materials will bring about the co-production of significant amounts of under-utilized lignin. The study examines the potential of conventional heterogeneous and novel homogeneous catalysts for the selective cleavage of the aryl-O-aryl and aryl-O-aliphatic linkages of ethanol organosolv lignin to convert it from a low grade fuel to potential fuel precursors or other value added chemicals. The experimental data demonstrated that aryl-O-aryl and aryl-O-aliphatic linkages could be cleaved and the hydrogenated lignin had a decrease in oxygen functionality and the formation of products with lower oxygen content. The second part of this thesis reports the development and optimization of a novel qualitative method for the determination of the various types of hydroxyl groups present in biodiesel production streams. In the first study, the use of 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane as a phosphitylation reagent for quantitative ³¹P-NMR analysis of the hydroxyl groups in biodiesel process samples has been developed. Subsequently a characteristic chemical shifts library is developed with model compounds to provide quantitative data on the concentration of biodiesel precursors, intermediates and final product. The last part of this thesis depicts the results of an industrial trial based on the novel biodiesel analytical method developed earlier.

In the search for fossil fuel alternatives the production of bio-oil through the pyrolysis of biomass is one method which has shown evidence of scalability, meaning that the technology could be scaled up for the processing of biomass on the order of tons per day. Pyrolysis is the thermal degradation of compounds in the absence of oxygen. Of particular interest is the pyrolysis of sustainable energy crops such as Loblolly pine (Pinus taeda). The goal of this study is to develop a new method of characterizing the fast pyrolysis of biomass for the advancement of reactor design. The objectives are to determine bulk kinetic coefficients for the isothermal fast pyrolysis of biomass, evaluate the interchangeability of fast and slow pyrolysis kinetic parameters and compare generally accepted pyrolysis mechanisms derived from a common data set. A technical objective is to apply the most suitable derived kinetic parameters to model pyrolysis within a moving bed reactor. A novel fast pyrolysis micro-reactor is presented along with its design and development process. The micro-reactor allows for the control over both temperature and residence time of the reacting biomass. This system provides the experimental data for the characterization of biomass pyrolysis kinetic parameters. Thermal validation tests are presented and experimental yield results are given for raw Loblolly Pine, Avicel cellulose and Beechwood xylan for the derivation of kinetic descriptors. Cellulose and xylan results show good agreement with literature when the proper experimental conditions are met and whole wood pyrolysis results clearly demonstrate the dissimilarity between fast and slow pyrolysis apparent kinetic rates. The experimental results are then used to evaluate five different pyrolysis kinetic model configurations: single component global pyrolysis, two component global pyrolysis, product based pyrolysis, pseudo-component based pyrolysis and pseudo-component pyrolysis with an intermediate solid compound. Pseudo-component models are of particular interest because they may provide a generalized model, parameterized by the fractional composition of cellulose, hemicellulose and lignin in biomass species. Lignin pyrolysis yields are calculated to evaluate the suitability of a pseudo-component parallel non-competing superposition pyrolysis model. Lignin yields are estimated by taking the difference between whole wood pyrolysis and predicted cellulose and hemicellulose pyrolysis behaviors. The five models are then evaluated by comparison of predicted yields to the results for the pyrolysis of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies). Model evaluations show that pseudo-component superposition is not suitable as a generic pyrolysis model for the fast pyrolysis of biomass observed using the micro-reactor. Further analytical evaluations indicate that the assumption of parallel non-competing reactions between pseudo-components is not valid. Among the other models investigated the intermediate solid compound model showed the best fit to the verification experimentation results followed closely by the two component global model. Finally, the derived kinetic parameters are applied to the design of moving bed vacuum pyrolysis reactors which provide for the separation of heat and mass transfer pathways, resulting in the reduction of char entrainment and secondary reactions within collected bio-oils. Reaction kinetics and porous bed heat and mass transfer are accounted for within the bed model. Model development and predictive results are presented and sensitivity to activation energy variations investigated.

The fractional catalytic pyrolysis of pine was studied both experimentally and through models. A preliminary stage economic analysis was conducted for a wood chip pyrolysis facility operating at a feed rate of 2000 wet ton/day for producing bio-oil. In the experimental study, multiple grams of bio oil were produced in a single run to facilitate the more extensive characterization of the oil produced from pyrolysis of biomass impregnated with different catalysts. Two reactors configurations, a screw extruder and a tubular pyrolysis reactor, were explored to perform fractional catalytic pyrolysis of biomass. The main aim of performing a wood pyrolysis reaction in a modified screw extruder is to facilitate the simultaneous collection of bio-oil produced from staged temperature pyrolysis of three main components of wood, cellulose, hemicellulose and lignin, at a reasonable scale. Apart from complete characterization of bio-oil, this will enable us to study the effect of various selected catalysts on the quality of bio-oil and the percentage of char produced, and the influence of process parameters on chemical composition of the pyrolysis oils. These experiments were later performed in a tubular pyrolysis reactor due to the difficulty of making different parts of the extruder work well together. The goal of these experiments is to produce bio-oil in multiple grams from fractional catalytic pyrolysis of wood. This will enable us to study the effect of catalyst on the chemical composition of the oil and percentage of char produced. In the modeling studies, a model of an auger reactor comprised of three different zones run at different temperatures to facilitate the collection of oil from pyrolysis of three major components of wood, namely cellulose, hemicelluloses and lignin, was developed. The effect of residence time distribution (RTD), and zone temperatures based on kinetic models on the yield of products was studied. Sensitivity of the Arrhenius rate constants calculated from synthetic data with respect to small variations in process parameters was evaluated. In the economic analysis of a wood chip pyrolysis facility, mass and energy calculations were performed based on a feed rate of 2000 wet tons/day of wood chips to the dryer. The cost of bio-oil at 10% return on investment was proposed and the sensitivity of the selling price of bio-oil with respect to capital and operating costs was analyzed. The experimental study will serve as a benchmark in exploring the above mentioned reactor configurations further. Alkali metal carbonates were used to study the quality of oil produced from pine pyrolysis. It was established that these catalysts, when added in the same molar ratio basis, increase the percentage of char. However, complete characterization of these oils for different catalysts needs to be done. Systems modeling of pyrolysis in an auger reactor established that the kinetic parameters (depending on experimental set up) and the RTD (Residence Time Distribution) parameters play a crucial role in determining the yield of oil. Variations in temperature of zone 3 play a crucial role in varying the output of oil whereas variations in temperatures of zones 2 and 1 do not significantly impact the output of oil. For a given reaction kinetic scheme for the pyrolysis reactions, calculated values of the kinetic rate constants are not sensitive to errors in experimental conditions. It was also established that the experimental error in calculation of the RTD parameters can induce error in calculation of the Arrhenius constants but these values can still predict the yield of products accurately. In the economic analysis of wood chip pyrolysis, the selling price of the bio-oil according to the cost calculation is projected to be $1.49/gal. The production cost of bio-oil is $ 1.20/gal. The cost of bio-oil is extremely sensitive to variations in operating cost (for example, cost of feed stock and selling price of char) and is not significantly affected by the variations in capital cost.

There are many problems associated with the use of fossil fuels to produce fuels and chemicals, and lignocellulosic biomass stands as a promising alternative fuel/chemical feedstock. Large scale processing of biomass will likely take place in high temperature liquid water due to the low vapor pressure and polar nature of carbohydrates. However, little is known about the material stability of these catalysts in high temperature aqueous phase environments. This dissertation aims to investigate the structural integrity of some common catalytic materials under typical biomass reforming conditions. There are 3 main objectives of this study: 1) identify potentially stable candidates from commonly used materials, 2) understand the mechanism(s) by which these catalysts degrade, 3) design/modify catalysts in an effort to increase their hydrothermal stability. The two main materials investigated in this work are zeolites (faujasite, ZSM-5) and γ-Al2O3 as these are commonly used as catalysts and catalyst supports. A number of physicochemical techniques were used to characterize the materials as a function of treatment time at conditions relevant for biomass reforming. For zeolites, the major findings are that ZSM-5 framework is highly stable whereas faujasite stability depends on the Si/Al ratio, where silicon rich materials are less stable. For γ-Al2O3 based catalysts, it was found that the alumina support hydrates and undergoes a phase transformation to form crystalline boehmite (AlOOH) with a subsequent loss in surface area and Lewis acid sites. When metal particles are present on the support, the phase change kinetics are slowed. The role of metal precursor on the stability of γ-Al2O3 supported catalysts was also explored, and it was found that the precursor used in catalyst synthesis changes the boehmite formation kinetics and also affects alumina support dissolution. The final thrust aims to stabilize a Pt/γ-Al2O3 catalyst by depositing silicon on the catalyst surface. The silicon modification is effective in protecting the catalyst from boehmite formation upon exposure to hot liquid water while also stabilizing metal particles against sintering. Additionally, an increase in turnover number for hydrogen production via aqueous phase reforming of sorbitol was observed.