The thesis primarily focuses on the pressure influence on the reaction rate of char gasification using laboratory thermogravimetric analysis (TGA). It discusses also the gasification of char with a mixture of gasifying agents (CO2 + steam) under a pressure of 40 bar and temperatures up to 1100°C, which has not been reported in the literature to the best of found knowledge. The first section investigates the pressure impact on char gasification kinetics by varying the total and partial pressure of the gasifying agent. The second section investigates the effect of gasifying agent at 40 bar and combining the pyrolysis step in the investigation, which was done in-situ under inert atmosphere. Then, mixtures of the two gasifying agents were used for the gasification in separate experiments. The third section uses raw coal as material and gives attention to the char structure formed after the pyrolysis under the high pressure. The fourth section includes measurements for char characteristics during the gasification reaction and compares them with the reference char data performed previously in this research group under atmospheric pressure.:Abstract 1. Introduction 1 1.1 Scope of the thesis 1 1.2 Layout of the thesis 2 2. Literature Review 4 2.1 Background 4 2.2 Coal and gasification 5 2.2.1 Coal classification and characteristics 5 2.2.2 Introduction to gasification process 7 2.2.3 Coal Analysis 10 2.2.4 Pyrolysis 13 2.2.5 Gasification reactions 13 2.2.6 Mechanism of solid-gas reaction and Thermodynamic background 14 2.2.7 Regimes of gas-Solid Reactions 17 2.2.8 Summary 19 2.3 Effect of Pressure on gasification process 20 2.3.1 Advantages of high-pressure operation 20 2.3.2 Influence on the pyrolysis step 20 2.3.3 Effect of Pressure on coal swelling 21 2.3.4 Pressure influence on char morphology 23 2.3.5 Effect of pyrolysis pressure on char surface area 23 2.3.6 Effect on reaction order n 24 2.3.7 Summary 24 2.4 Pressure influence on char gasification reaction kinetics 24 2.4.1 Pressure influence on gasification reaction kinetics 25 2.4.2 Summary 27 2.5 Char gasification using gasifying agent mixtures 27 2.5.1 Mechanism 29 2.5.2 The role of the inhibition and the catalytic effect 29 2.5.3 Summary 32 2.6 Thermodynamic aspects and the estimation of the reaction rate 32 2.6.1 Background 32 2.6.2 Basic definitions of reaction rate 34 2.6.3 Intrinsic kinetic models 35 2.6.4 Theoretical models 36 2.6.5 Empiric Models 39 2.6.6 Intrinsic kinetic models expressed by CO2 concentration 40 2.6.7 Arrhenius Activation Energy 40 2.6.8 Differentiation of a polynomial fit data (Differential method): 41 2.6.9 Summary 43 3. Experimental Analysis 44 3.1 Thermogravimetry 44 3.2 Testing of the gas volume fraction and the total pressure influence on char gasification 45 3.2.1 Testing of the gas volume fraction influence 45 3.2.2 Testing of system pressure influence on char gasification 56 3.2.3 Discussion 65 3.3 Coal gasification at 40 bar with pure CO2, H2O and their mixtures 65 3.3.1 Gasification with pure CO2 and H2O 66 3.3.2 Coal gasification using CO2 / H2O mixtures at high system pressure 87 3.3.3 Discussion 96 3.4 Pressure influence on coal gasification 100 3.4.1 Coal gasification under different system pressures 100 3.4.2 The effect of increasing pressure on coal morphology 104 3.4.3 Discussion 117 3.5 Influence of the pressure on the char properties during gasification 118 3.5.1 Discussion 129 4. General discussion 134 5. Conclusions 139 5.1 Significance of the findings 143 5.2 Recommendations 144 6. Appendix 146 6.1 Literature and Results 146 6.1.1 Conditions influence on gasification of the (a) temperature, (b) partial pressure 146 6.1.2 TGA-DMT 147 6.1.3 Testing of the gas volume fraction influence on coal gasification 148 6.1.4 Testing of system pressure influence on char gasification 150 6.1.5 Coal gasification at 40 bar with pure CO2, H2O and their mixtures 152 6.1.6 Coal gasification under different pressures 162 6.1.7 Summary of gas mixture gasification studies 167 6.2 Figures Index 169 6.3 Tables Index 175 6.4 References 177

Thermo-stabilized lignin fibers from pH-fractionated softwood kraft lignin were carbonized to various temperatures during thermomechanical analysis (TMA) under static and increasing load and different rates of heating. The aim was to optimize the carbonization process to obtain suitable carbon fiber material with good mechanical strength potential (high tensile strength and high E-modulus). The carbon fibers were therefore mainly evaluated of mechanical strength in Dia-Stron uniaxial tensile testing. In addition, chemical composition, in terms of functional groups, and elemental (atomic) composition was studied in Fourier transform infrared spectroscopy (FTIR) and in energy-dispersive X-ray spectroscopy (EDS), respectively. The structure of carbon fibers was imaged in scanning electron microscope (SEM) and light microscopy. Thermogravimetrical analysis was performed on thermo-stabilized lignin fibers to evaluate the loss of mass and to calculate the stress-changes and diameter-changes that occur during carbonization. The TMA-analysis of the deformation showed, for thermo-stabilized lignin fibers, a characteristic behavior of contraction during carbonization. Carbonization temperatures above 1000°C seemed most efficient in terms of E-modulus and tensile strength whereas rate of heating did not matter considerably. The E-modulus for the fibers was improved significantly by slowly increasing the load during the carbonization. The tensile strength remained however unchanged. The FTIR-analysis indicated that many functional groups, mainly oxygen containing, dissociate from the lignin polymers during carbonization. The EDS supported this by showing that the oxygen content decreased. Accordingly, the relative carbon content increased passively to around 90% at 1000°C. Aromatic structures in the carbon fibers are thought to contribute to the mechanical strength and are likely formed during the carbonization. However, the FTIR result showed no evident signs that aromatic structures had been formed, possible due to some difficulties with the KBr-method. In the SEM and light microscopy imaging one could observe that porous formations on the surface of the fibers increased as the temperature increased in the carbonization. These formations may have affected the mechanical strength of the carbon fibers, mainly tensile strength. The carbonization process was optimized in the sense that any heating rate can be used. No restriction in production speed exists. The carbonization should be run to at least 1000°C to achieve maximum mechanical strength, both in E-modulus and tensile strength. To improve the E-modulus further, a slowly increasing load can be applied to the lignin fibers during carbonization. The earlier the force is applied, to counteract the lignin fiber contraction that occurs (namely around 300°C), the better. However, in terms of mechanical performance, the lignin carbon fibers are still far from practical use in the industry.

Soy flour (SF), a by-product of the soybean oil extraction processing, was investigated for its application in soy-polypropylene composites for interior automotive applications. The emphasis of this work was the understanding of this new type of filler material and the contribution of its major constituents to its thermal stability and impact properties. For this reason, reference materials were selected to represent the protein (soy protein isolate (SPI)) and carbohydrate (soy hulls (SH)) constituents of the soy flour. Additional materials were also investigated: the residue obtained after the protein removal from the soy flour which was called insoluble soy (IS), and the remaining liquid solution after acid precipitation of the proteins, containing mostly sugars and minerals, which was called soluble sugar extract (SSE). Two treatments, potassium permanganate and autoclave, were analyzed for their potential to modify the properties of the soy composite materials. An acid treatment with sulfuric acid conducted on soy flour was also considered. The soy materials were studied by thermogravimetric analysis (TGA) under isothermal (in air) and dynamic (in nitrogen) conditions. SPI had the highest thermal stability and SSE the lowest thermal stability for the early stage of the heating process. Those two materials had the highest amount of residual mass at the end of the dynamic TGA in nitrogen. The two treatments showed minimal effect on the isothermal thermal stability of the soy materials at 200 ??C. A minor improvement was observed for the autoclave treated soy materials. Fourier transformed infrared (FTIR) spectroscopy indicated that the chemical surface composition differed according to type of the soy materials but no difference could be observed for the treatments within one type of soy material. Contact angle analysis and surface energy estimation indicated differences of the surface hydrophobicity of the soy materials according to type of material and treatment. The initial water contact angle ranged from 57 ?? for SF to 85 ?? for SH. The rate of water absorption increased dramatically after the autoclave treatment for IS and SPI. Both materials showed the highest increase in the polar surface energy fraction. In general, the major change of the surface energy was associated with change of the polar fraction. After KMnO4 treatment, the polar surface energy of SF, IS and SPI decreased while SH showed a slight increase after KMnO4 treatment. A relationship between protein content and polar surface energy was observed and seen to be more pronounced when high protein containing soy materials were treated with KMnO4 and autoclave. Based on the polar surface energy results, the most suitable soy materials for polypropylene compounding are SPI (KMnO4), SH, and IS (KMnO4) because their polar surface energy are the lowest which should make them more compatible with non-polar polymers such as polypropylene. The soy materials were compounded as 30 wt-% material loading with an injection moulding grade polypropylene blend for different combinations of soy material treatment and coupling agents. Notched Izod impact and flexural strength as well as flexural modulus estimates indicated that the mechanical properties of the autoclaved SF decreased when compared to untreated soy flour while the potassium permanganate treated SF improved in impact and flexural properties. Combinations of the two treatments and two selected (maleic anhydride grafted polypropylene) coupling agents showed improved impact and flexural properties for the autoclaved soy flour but decreased properties for the potassium permanganate treated soy flour. Scanning electron microscopy of the fractured section, obtained after impact testing of the composite material, revealed different crack propagation mechanisms for the treated SF. Autoclaved SF had a poor interface with large gaps between the material and the polypropylene matrix. After the addition of a maleic anhydride coupling agent to the autoclaved SF and polypropylene formulation, the SF was fully embedded in the polymer matrix. Potassium permanganate treated SF showed partial bonding between the material and the polymer matrix but some of the material showed poor bonding to the matrix. The acid treated SF showed cracks through the dispersed phase and completely broken components that did not bind to the polypropylene matrix. In conclusion, the two most promising soy materials in terms of impact and flexural properties improvement of soy polypropylene composites were potassium permanganate treated SF and the autoclaved SF combined with maleic anhydride coupling agent formulation.

The study examined the properties of stalk and cob fibres from recombinant inbred corn lines and their parents, grown at two locations, in a polylactic acid (PLA) matrix. The objectives were to: determine fibre compositions; evaluate the effects of fibres on the functional properties of biocomposites and identify quantitative trait loci (QTLs) and gene markers for fibre performance in biocomposites. Significant Genotype*Location effects were observed. Composites had lower strength (impact, tensile, and flexural) but higher tensile/flexural modulus values than pure PLA. The latter were positively affected by cellulose and hemicellulose but negatively affected by free phenolic levels and 93 fibre QTLs and 62 composite markers were detected. This study identified fibre traits and markers for genes that may be important for the use of corn fibres in biocomposites. / Ontario BioCar Initiative Project funded by Ontario Ministry of Research and Innovation, Agriculture and Agri-Food Canada, The Natural Sciences and Engineering Research Council, The Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) and Ontario Public Sector