Pyrolysis oil is produced from biomass when a feedstock is rapidly heated in a non-oxidizing environment during a short residence time. While pyrolysis oil is inexpensive, major issues prevent the facile use of this oil product ‘as produced’. Principally, since the rapid condensation results in a product not in thermodynamic equilibrium, the oil components continue to react until equilibrium is reached. Understanding how and why these reactions—including polymerization—occur in pyrolysis oil is important in designing treatments to stabilize or transform pyrolysis oil before further upgrading. Physical and chemical changes in pyrolysis oils are investigated as a function of temperature and time to simulate the aging process during storage. The effects of alcohol addition on pyrolysis oil stability during high temperature treatment are investigated. The pretreatment of pyrolysis oil with low-cost alcohols is promising prior to hydrotreating or catalytic cracking.

In this work, an investigation on the fraction of tyre pyrolysis oil with a similar distillation range to that of automotive diesel (150 – 360 oC) was carried out to determine its suitability as an alternative or additive to petro-diesel fuel. The quality of this oil was evaluated by comparing its key properties to the requirements of South African National Standards for Automotive diesel fuel (SANS-342) and to conventional automotive diesel fuel. The viscosity, density, copper strip corrosion of this fuel were found to be within the acceptable limits set by SANS while sulphur content and flash point were out of their respective set limits. In addition, mixing rule equations for predicting viscosity and density for both pure and blends of the oil as a function of temperature were developed and evaluated. The equations were found to be suitable due to their low Absolute Percentage Deviation. Engine performance tests were carried out with blends of Distilled Tyre Pyrolysis Oil (DTPO) and petro-diesel fuel in a single cylinder air cooled diesel engine. The performance, emission and combustion characteristics of the diesel engine while running on these blends were evaluated and subsequently, a comparative analysis was performed with conventional petro-diesel fuel as the reference fuel. It was found that, the engine could run with up to 60% (DTPO) without any problem. Beyond this level the engine became unstable. The power and torque were similar at low and medium speeds. However, at high speeds, the power dropped with increase in DTPO in the blend. Fuel consumption was very comparable for all the test fuels. Carbon monoxide and unburned hydrocarbons were higher for the blends compared to petro-diesel fuel but oxides of Nitrogen were lower. The peak pressure for petro-diesel fuel was marginally higher than that of the blends. Present results indicate that, petro-diesel fuel can be blended with up to 60% DTPO and produce acceptable performance. Testing the diesel engine under different operating conditions is a time consuming and expensive process that also requires the use of specialised equipment which may not be readily available. An Artificial Neural Network (ANN) model based on a back-propagation learning algorithm was developed to predict engine performance and emissions separately, based on fuel blend and speed. The performance and accuracy of the model were evaluated by comparing experimental and ANN predicted results. The ANN was able to predict both engine performance and emissions with acceptable levels of accuracy. The values of correlation coefficient between experimental and predicted data being greater than 0.99. From this work, it can be implied that engine emission and performance can be predicted using neural network-based mode, consequently, it will be able to do further investigations without running laboratory experiments. Energy recovery from waste is an interesting field for engineers and scientists. It is hoped that this work will prompt new research ideals on how tyre pyrolysis oil can be improved for use as diesel engine fuel and building better models for diesel engine performance and emissions

Phenol-formaldehyde adhesives are important adhesives known to have superior water resistance capacity and high mechanical strength when utilized in wood-based applications. Due to unsustainability and environmental issues associated with the use of fossil fuels, there is an urgent need to look for alternative raw materials, which are renewable in nature. Pinyon-juniper biomass has been found to be a suitable replacement for petroleum-based phenol because it is renewable, abundant, and readily available. In this thesis, bio-oil produced from the pyrolysis of pinyon-juniper biomass using red mud alumina catalyst was used to produce wood adhesives. The characterization of pinyon-juniper bio-oil showed the presence of phenolics, aromatic hydrocarbons, aliphatic hydrocarbons, carboxylic acids, ethers, ketones, aldehydes, and aliphatic alcohols. Resol synthesis parameters such as formaldehyde-to-phenol molar ratio (1.8 and 2), catalyst loading (0.25, 0.63, and 1.25 g of NaOH), reaction time (60 minutes), and reaction temperature (95°C), were investigated in the production of pinyon-juniper adhesives. Based on the results obtained, the extent of phenol substitution with pinyon-juniper bio-oil was dependent on the amount catalyst used during the synthesis process. The maximum phenol substitution of 80% was achieved using a catalyst loading of 1.25 g of NaOH while the minimum phenol substitution of 50% was obtained at a catalyst loading of 0.25 g of NaOH. Dry shear strength (8.99 to 12.73 MPa) and wet shear strength of (5.16 to 7.36 MPa) for both pure phenol-formaldehyde resols and pinyon-juniper substituted resols were comparable and exceeded the minimum requirement of 0.66 MPa for plywood. Finally, the chemical structure of pure phenol-formaldehyde resols showed the presence of more phenolic OH groups compared to pinyon-juniper substituted resols. This observation was corroborated by the higher concentration of free phenol in pure phenol-formaldehyde adhesives compared to pinyon-juniper substituted resols.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19196号 / 農博第2135号 / 新制||農||1034(附属図書館) / 学位論文||H27||N4942(農学部図書室) / 32188 / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 吉村 剛, 教授 髙野 俊幸, 教授 渡邊 隆司 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

The physicochemical properties of pyrolysis oil have been shown to be dependent on feedstock composition. Accelerated aging tests were performed to understand the effects of feedstock, condensate fraction collected, and filtration on the stability of pyrolysis oil. In this study, pyrolysis oil properties critical for downstream upgrading were measured and compared for different feedstock weight ratios of pine clearwood and pine bark. Post-condensation filtration of pyrolysis oil was evaluated using both lab-scale and pilot plant-scale centrifugal filtration with several operational parameters evaluated. The pilot-plant centrifuge can be used as a three-phase separator [light liquid-heavy liquid-solids] or a two-phase clarifier [liquid-solid]. Since pyrolysis oil is an oil-water micro-emulsion, separation of the heavy and light liquid phases is difficult; therefore, emulsion destabilization studies were performed in concert with centrifugation. Physicochemical properties were monitored to determine the impact of the production and processing parameters on the oil properties critical to biofuel applications.

L’Afrique de l'Ouest manque de ressources naturelles pour la production d'énergie. Les sous-produits agro-industriels comme les coques d’anacarde (CNS), les tourteaux de jatropha et de karité ont été identifiés comme des ressources disponibles et facilement mobilisables à des fins énergétiques. Ces biomasses se caractérisent par de fortes teneurs en extractibles (baume de cajou=CNSL ou triglycérides), sources de fumées toxiques en combustion. La thèse visait à évaluer la pertinence de la pyrolyse rapide comme procédé alternatif pour ces ressources, etplus particulièrement à établir l'impact des extractibles sur les rendements, la composition et la stabilité des bio-huiles. Les biomasses ont été dérivées en échantillons couvrant la gamme entière des teneurs en extractibles (tourteau déshuilé ~0% ; extractible purs 100%), lesquels ont été caractérisés et pyrolysés dans 2 dispositifs laboratoires (ATG et four tubulaire), puis en conditions réelles sur un pilote de pyrolyse rapide à lit fluidisé. On ne constate pas d'interaction significative entre la matrice solide et les extractibles lors de leur décomposition, mais des produits différents ont été identifiés. Le CNSL se volatilise entre 250 et 320°C ; plusieurs composés phénoliques ou typiques du CNSL brut se retrouvent dans l'huile de pyrolyse. En revanche, les triglycérides se décomposent entièrement entre 380 et 420°C en chaînes d’hydrocarbures linéaires. Quelques produits d'interaction avec les triglycérides et les protéines ont été identifiés. Par ailleurs, les essais sur pilote ont mis en évidence des difficultés opérationnelles dans le lit fluidisé liées aux spécificités des tourteaux, suggérant une optimisation des conditions opératoires. Pour pallier la séparation de phases constatée sur les bio-huiles, des formulations avec d'autres biocarburants ont été testées. Les émulsions obtenues sont plus homogènes, mais leur stabilité physique est encore insuffisante malgré l'ajout / Sub-Saharan West Africa lacks of natural resources, especially for energy production. By-products of agro-industry as cashew nut shells (CNS), jatropha (Jc) and shea (Sc) press cakes were identified as available resources for energetic valorisation. These biomasses are characterized by high extractive contents (cashew nut shell liquid/CNSL or triglycerides) which are the reason for toxic fumes during combustion. The thesis investigated the feasibility of flash pyrolysis as alternative process for these resources, more specifically the impact of the extractives on yields, the composition and the stability of flash pyrolysis oils. The feedstock were derived into samples covering the whole range of extractive contents (from de-oiled press cakes, ~0 wt%; to pure extractives, 100 wt%) which were characterized and pyrolysed in two laboratory devices (TGA and tubular furnace), then by applying flash pyrolysis conditions in a fluidized bed reactor. No significant interaction in-between the solid matrix and the extractives during pyrolysis were observed but different products were identified. CNSL volatises between 250 and 320°C, several phenolic compounds and typical compounds of crude CNSL were found to be present in the pyrolysis oil. In contrast, triglycerides are entirely decomposed at 380 to 420°C to give linear hydro-carbon chains. Some interaction products of the triglycerides with proteins were identified. Additionally, the experiments with the pilot plant have shown operational difficulties in the fluidized bed, which are linked to specific properties of the press cakes. Thus, further optimisations of process conditions are suggested. To overcome the observed phase separation of the pyrolysis oils mixtures with other biofuels were studied. The obtained emulsions are more homogeneous but the physical stability is still insufficient despite the addition of surfactants.

Catalytic hydrodeoxygenation (HDO), is an effective process to convert oxygenated compounds to hydrocarbons. This process is widely used for improving the negative properties of biomass-derived pyrolysis oils (bio-oils) such as high acidity, poor stability, and low heating value. During this process oxygen is removed from the bio-oil in the form of water, thus the liquid product of HDO process consists of aqueous phase and hydrocarbon phase that can be easily separated. Synthesis of efficient HDO catalyst has been a major challenge in the field of bio-oil upgrading. Red mud, which is an alkaline waste from alumina industry was used to develop a new red mud-supported nickel catalyst (Ni/RM) for the HDO of pinyon-juniper catalytic pyrolysis oil. The new catalyst was more effective than the commercial Ni/silica-alumina catalyst for the HDO of organic phase pyrolysis oil, the aqueous phase pyrolysis oil, and bio-oil model compounds. Less hydrogen was consumed in the case of Ni/RM and more liquid hydrocarbon yield was obtained compared to the commercial catalyst. In addition to HDO reactions, the Ni/RM catalyst catalyzed ketonization and carbonyl alkylation reactions that was important to produce liquid hydrocarbon from low molecular weight oxygenated compounds. Unlike the commercial catalyst, Ni/RM was regenerable by burning off the deposited coke and activation by reduction using hydrogen.

Pyrolysis oil is known to be unstable due to polycondensation reactions that negatively affect properties, such as increased viscosity and water content, lower heating values, and phase separation. Filtration of particulates and solid content out of the pyrolysis oil has been proven to increase stability, thus a filtration system was designed for pilot scale testing for the Mississippi State University Sustainable Energy Research Center (SERC). A literature review was conducted to determine potentially effective methods and eliminate methods likely to not improve the pyrolysis oil properties and stability. An in-line centrifuge system was identified as a useful and cost effective way to remove solids from the pyrolysis oil with an added benefit of potentially removing water content through a three-phase separation configuration. Lab-scale testing of centrifugation on pyrolysis oil indicated both two phase (solid + oil phases) and three phase (solid + aqueous phase + oil phases) separations could be obtained depending on feedstock and pyrolysis oil characteristics, and that centrifugation was a viable option for the removal of solid content. KiOR, Inc. pine clear wood derived pyrolysis oil (formerly known as ReCrude™) was characterized to determine physicochemical properties in comparison to literature results. Aging tests were also performed to investigate stability. In comparison with literature data, the properties for the KiOR product indicated significantly lower water content, particulate matter loading, and viscosity coupled with higher heating and pH values, indicating a product much closer in composition to fossil fuel oils than other pyrolysis oils. The KiOR ReCrudeM™ oil also demonstrated a much higher degree of stability versus other pyrolysis oils; however, there are still some stability issues with the aged samples resulting in slightly higher water content and viscosity values and lower heating and pH values. It is recommended that stability testing (aging) be performed on aliquots separated using a method such as rotary evaporation to more accurately determine what mechanisms are resulting in the properties changes observed over time in response to elevated temperature and/or pressure.

Studies of aging processes were conducted on pyrolysis oils produced from pine and cottonwood biomass (clear wood, whole tree, bark and needles/leaves). Accelerated aging at 80 °C for up to 504 h was employed to investigate the short and long-term effects of feedstock, phase separation, char particulates, and solvent addition on pyrolysis oil properties. Feedstock containing forestry residue was found to increase water content of neat pyrolysis oil and the collection method (total vs. fractionated) affects all of the properties with the largest impact on viscosity and as produced molecular weight. Post-condensation liquid filtration did not prevent aging-related water content or molecular weight increases during aging but did retard aging reactions in pine clear wood and pine bark pyrolysis oils. Methanol addition retarded the aging reactions in pine needle fractionated pyrolysis oil; at 15 wt% phase separation was prevented and molecular weight increased 11 % after 504 h of aging.

In this report, modifications and experimental tests with an early stage test rig intended for producing a commercial solution to fractionating pyrolysis oil are described. The idea is to use centrifugal force to separate the formed aerosols from condensible gases with a lower volatility. A stacked disc centrifuge prototype built to work at high temperature was used. The experiment was done with a single component, 1-Methylnaphtalene (1-MN) to evaluate the functionality of the test rig. No separation was achieved, concluding that further work need to be done at different operating parameters with 1-Methylnaphtalene prior to including more components. The reason for the negative separation result is probably due to that the saturation ratio was to low resulting in that no aerosol was formed during the experiments. Further work includes improving the stability of the inlet stream to the centrifuge. Perform more experiments with other process parameters, recommendation is to decreasing the temperature at the inlet to the centrifuge to increase the saturation ratio. It is also suggested that an optical in situ measuring devise is added to the test rig to facilitate operation.