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The Biomass Integrated Gasification Application Systems (BIGAS) consortium is a research group whose focus is on developing modern biomass gasification technology for New Zealand's wood industry. This thesis is undertaken under objective four of the BIGAS consortium, whose goal is to develop modelling tools for aiding in the design of pilot-scale gasification plant and for assessing the economic feasibility of gasification energy plant. This thesis presents a chemical equilibrium-based gasification model and an economic feasibility assessment of gasification energy plant. Chemical equilibrium is proven to accurately predict product gas composition for large scale, greater than one megawatt thermal, updraft gasification. However, chemical equilibrium does not perform as well for small scale, 100 to 150 kilowatt thermal, Fast Internally Circulating Fluidised Bed (FICFB) gasification. Chemical equilibrium provides a number of insights on how altering gasification parameters will affect the composition of the product gas and will provide a useful tool in the design of pilot-scale plant. The economic model gives a basis for judging the optimal process and the overall appeal of integrating biomass gasification-based heat and power plants into New Zealand's MDF industry. The model is what Gerrard (2000) defines as a 'study estimate' model which has a probable range of accuracy of ±20% to ±30%. The modelling results show that gasification-gas engine plants are economically appealing when sized to meet the internal electricity demands of an MDF plant. However, biomass gasification combined cycle plants (BIGCC) and gasificationgas turbine plants are proven to be uneconomic in the New Zealand context.

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Bioprocesses carried out for the production of fuels and other value-added co-products require effective process control strategies. The objective of this research is to apply Titrimetric Off-Gas Analysis (TOGA) for the on-line estimation of fermentation end products using Clostridium thermocellum. The hydrogen ion production, gaseous H2 and CO2, soluble H2 and CO2, as well as ethanol in the liquid phase and vapour phase, were monitored. All parameters, except the dissolved gases, showed good correlation with concurrent off-line analysis. The resulting mass and electron balances were close to theoretical values, and not significantly different from those determined using off-line analysis. Liquid-to-gas mass transfer limitations caused supersaturation of H2(aq) for a wide-range of operating conditions, and on average, ranged between 8-14 times the expected value at thermodynamic equilibrium. The supersaturation of CO2(aq) was conditional, and could be alleviated by increased sparging at agitation such that no significant mass transfer limitation was present. Simultaneous data on ethanol, CO2, and H2 could be obtained with the MIMS probe placed adjacent to the liquid surface in the reactor headspace. From this data, a metabolic model was proposed for the on-line estimation of formate and acetate using a mass balance and an electron balance. The model estimated formate concentrations with reasonable accuracy. Acetate predictions agreed with the qualitative trends, but the concentrations were inaccurate in comparison with off-line analysis. It was demonstrated that the sensor could provide on-line information on all major end-products synthesized by C. thermocellum. In conclusion, TOGA is a valuable instrument for the on-line monitoring and study of fermentation processes for cellulosic biofuels production

A novel compacted, torrefied, spherical biomass pellet, known as the "Q'Pellet", is aimed at overcoming the challenges of modern biomass pellets by building on the bene fits of torrefaction and utilizing the durability of a sphere. Pellets were made from both untreated hybrid poplar sawdust and material that had been partially torrefied at 250 C, allowing the torrefaction and pelletizing stages to be decoupled. A pelletizing die pre-heated to 280 C was successfully used to heat and torrefy room temperature raw and pre-torrefi ed material, greatly reducing the time required to produce each pellet. All Q'Pellets demonstrated 100% mechanical durability, and did not abrade during a tumbling can test or fracture during an impact resistance (drop) test. The gross calori fic value (GCV), ash and nitrogen content of pellets produced from raw hybrid poplar were 21.29+/-0.08 MJ/kg, 2.42+/-0.23 wt%, and <0.01 wt%, respectively. The GCV, ash and nitrogen content of pellets produced from pre-torre ed material were 21.25+/-0.34 MJ/kg, 3.58+/-1.11 wt%, and 0.42+/-0.03 wt%, respectively. The Q'Pellet was compared to biomass fuel speci fications in Europe and North America. The experiments performed herein provided an understanding of the material and process properties and limitations. Design speci fications for the development of a continuous pelletizing process were outlined. BGM Metalworks Inc has been hired by Queen's University to assist in the design and to fabricate the continuous pelletizing apparatus. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2014-05-06 14:04:54.059

Knowledge of nutrient accumulation and partitioning in plants is important to determine the optimum timing of harvesting during phytoremediation of biosolids. This research showed that a greater proportion of nitrogen (N) and phosphorus (P) absorbed by cattail and switchgrass was partitioned to the aboveground biomass (AGB), but this partition decreased after the onset of nutrient retranslocation to roots. Therefore, AGB should be harvested prior to retranslocation in order to optimize nutrient phytoextraction. Trace elements partitioned preferentially to the root biomass, indicating that AGB harvesting will have little impact on their phytoextraction. Net mineralized N concentration (Nmin) in biosolids from the primary lagoon cell was optimized near field capacity [60% water filled pore space (WFPS) but changed little under drier conditions (30% WFPS). Under near-saturation conditions (90% WFPS), net Nmin decreased with incubation time, likely due to reduced mineralization and denitrification. Available (Olsen) P concentration was not affected by moisture content.

Catalytic supercritical water gasification (SCWG) is a promising technology for hydrogen and methane production from wet organic feedstocks at relatively low temperatures (e.g. <500 oC). However, in order to make this process technically and economically viable, solid catalyst with enhanced activity and improved hydrogen selectivity should be developed. In this study, different aspects of catalytic SCWG have been investigated. The performance of several supported-nickel catalysts were examined to identify catalysts that lead to high carbon conversion and high hydrogen yields under near-critical conditions (i.e. near 374 oC). Moreover, for the first time, the effects of several parameters which dominated the activity of the supported nickel catalysts have been systematically investigated. Among the several different catalyst supports evaluated at 5% nickel loading, α-Al2O3, carbon nanotube (CNT), and MgO supports resulted in highest carbon conversions, while SiO2, Y2O3, hydrotalcite, yttria-stabilized zirconia (YSZ), and TiO2 showed modest activities. Comparing the XRD patterns for the support materials before and after the exposure to supercritical water, α-Al2O3, YSZ, and TiO2 were found to be hydrothermally stable among the metal oxide supports. Using the same amount of nickel on α-Al2O3, the methane yield decreased by increasing the nickel to support ratio whereas the carbon conversion was only slightly affected. At a given nickel to support ratio, a threefold increase in methane yield was observed by increasing the temperature from 350 to 410 oC. The catalytic activity also increased by the addition small quantity of potassium. The activity of Ni/γ-Al2O3 catalyst varied based on the affinity of the catalyst to form nickel aluminate spinel. This is also the first report on the role of oxidative pretreatment of the carbon nanotubes by nitric acid on the performance of these catalysts for the supercritical water gasification process. Using different lignocellulosic feeds, it was found that the gasification of glucose, fructose, cellulose, xylan and pulp resulted in comparable gas yields (± 10%) after 60 min, whereas alkali lignin was substantially harder to gasify. Interestingly, gasification yield of bark, which had a high lignin content, was comparable to those of cellulose. In summary, the Ni/α-Al2O3 catalyst had a higher hydrogen selectivity and comparable catalytic activity to the best commercially available catalysts for SCWG of carbohydrates.

Gasification technologies are expected to play a key role in the future of solid waste management since the conversion of municipal and industrial solid wastes to a gaseous fuel significantly increases its value. Municipal solid waste (MSW) gasification for electrical power generation was conducted in a fluidized bed gasifier and the feasibility of using a control system was evaluated to facilitate its management and operation. The performance of an engine using the gas produced was evaluated. A procedure was also tested to upgrade the quality of the gas and optimize its production. The devices installed and automated control system developed was able to achieve and maintain the set conditions for optimum gasification. The most important parameters of reaction temperature and equivalence ratio were fully controlled. Gas production went at a rate of 4.00 kg min-1 with a yield of 2.78 m3 kg-1 of fuel and a heating value (HV) of 7.94 MJ Nm-3. Within the set limits of the tests, the highest production of synthesis gas and the net heating value of 8.97 MJ Nm-3 resulted from gasification at 725°C and ER of 0.25 which was very close to the predicted value of 7.47 MJ Nm-3. This was not affected by temperature but significantly affected by the equivalence ratio. The overall engine-generator efficiency at 7.5 kW electrical power load was lower at 19.81% for gasoline fueled engine compared to 35.27% for synthesis gas. The pressure swing adsorption (PSA) system increased the net heating value of the product gas by an average of 38% gas over that of inlet gas. There were no traces of carbon dioxide in the product gas indicating that it had been completely adsorbed by the system. MSW showed relatively lower fouling and slagging tendencies than cotton gin trash (CGT) and dairy manure (DM). This was further supported by the compressive strength measurements of the ash of MSW, CGT and DM and the EDS elemental analysis of the MSW ash.

Grasslands are the most important ecosystem to humanity, as they are responsible for feeding that majority of the human population. These are also very large ecosystems; they cover approximately 40% of the surface of the earth (Loveland et al., 1998), making ground-based surveys for monitoring grassland health and productivity extremely time consuming. Remote sensing has the advantage of providing reliable and repeatable observations over large swaths of land; however, optical sensors exploiting the visible and near infrared regions of electromagnetic (EM) spectrum will be unable to collect information from the ground if clouds are present (Wang et al., 2009). Imaging radar sensors, the most common being synthetic aperture radar (SAR), have the advantage of being able to image the ground even during cloudy conditions. The longer wavelengths of EM energy used by the SAR sensor are able to penetrate clouds while shorter wavelength used by optical sensors are scattered. A grassland monitoring tool based on SAR imagery would have many advantages over an optical imagery system, especially when SAR data becomes widely available. To demonstrate the feasibility of grassland monitoring using SAR, this study experimented with a set of dual-polarimetric SAR imagery to extract several grassland biophysical parameters such as soil moisture, canopy moisture, and green grass biomass over the mixed grassland in southwestern Saskatchewan. Soil moisture was derived from these images using the simple Delta Index (Thoma et al., 2006) first developed for a sparsely vegetated landscape. The Delta Index was found to explain 80% of the variation in soil moisture, in this vegetated landscape. Canopy moisture was modeled using the water cloud model (Attema and Ulaby, 1978). This model has a similar explanatory power of R2 = 0.80. This study found that only the photosynthesizing green grass biomass had a significant relationship with the canopy moisture model. However, only about 40% of the variation in green grass biomass can be explained by canopy moisture alone. The cross-polarized ratio developed from the dual polarimetric images was found to reflect the plant form diversity of the grassland. Biophysical parameters extracted from optical satellite imagery, Landsat-5 in the case of this study, were compared to those derived from the SAR images. This comparison revealed that the SAR images were superior in sensitivity to soil and canopy moisture. Optical imagery was found to be more sensitive to green canopy cover. An approach combining the results from both sensors showed an improvement in green grass biomass estimation (Adjusted R2 = 0.71).