Land-based turbine engines are currently used to burn heavy fuel oil (HFO), which is a lower cost fuel. HFO contains inorganic material that forms deposits on turbine blades reducing output and efficiency. Magnesium based additives are used to inhibit vanadium pentoxide deposition and reduce the corrosive nature of the gas and deposits in the hot gas path of the gas turbine. The focus of this study was to determine particle morphology and elemental composition of ash when firing HFO in an atmospheric combustor at various fuel injector atomization pressures. Prior to firing, the HFO was washed with water to remove sodium and potassium. A commercially available magnesium based additive was used to inhibit the vanadium in the HFO. Fuel was injected using an air-blast atomizer at air blast atomization gage pressures of 117, 186, and 255 kPa. Ash was collected from three locations downstream of combustion: immediately following combustion (pre-cyclone), from a cyclone separator (cyclone), and finally from a position located after the cyclone separator (post-cyclone). A Philips XL30 Scanning Electron Microscope (SEM) provided images, weight percent of elements of the ash, and element maps. Images taken from the SEM clearly show two particle types: 1) hollow spherical particles, or cenospheres, and 2) submicron agglomerated spherical particles. The cenospheres contained high carbon concentrations and were found primarily in the cyclone and probe bag filter. Element maps show that cenospheres, regardless of size, predominately contain carbon, oxygen, and sulfur with lesser amounts of sodium, magnesium, aluminum, and silicon. Particles collected downstream of the cyclone were primarily sub-micron in size and inorganic in composition. It is postulated that the cenospheres are the result of incomplete combustion of fuel oil droplets while the submicron spheres are nucleated inorganic material that initially evaporated from the liquid droplets. Particle size analysis was performed for each sample location. As the injection pressure was increased; the pre-cyclone and cyclone locations had similar number mean diameters that would decrease with increasing pressure. The diameter of the post-cyclone location did not change significantly with increasing air atomization. While increasing atomization pressure decreased the carbon content of the ash at all measurement locations, the atomization had little influence on the inorganic composition of the particles. The fine condensed phase particles and the larger cenosphere particles both produced similar compositions of inorganic material.

<p dir="ltr">Flow patterns in a toroidal-fluidized bed granulator were analyzed using the effects of wall friction on the bed pressure drop. Toroidal flows were generated by directionally inclined jets from a radially-slotted distributor plate. The relatively small open area of the slotted distributor provides significant jet velocities, inducing toroidal flow even at relatively low superficial airflows. In this aspect, the process is of interest to fluidized bed granulation wherein the toroidal flow can assist spray flux without excessive elutriation. The current dissertation explores the effect of toroidal multiphase flow on wall friction and pressure drop. Relevant process parameters include particle size, airflow, temperature, and bed inventory. Particle size growth is especially important in fluidized bed granulation; airflow and temperature parameters must balance with the binder spray enthalpy; and the bed inventory is relevant to capacity and throughput analyses. An empirical process model was developed to guide fluidized bed granulation with a consistent pressure-drop balance across the distributor plate and product bed during the granulation process.</p><p dir="ltr">Fluidized bed granulation integrates several process transformations into a single unit operation. Transformations include powder fluidization, atomization of binder solution and wetting of the fluidized powder, growth and consolidation of granules, drying, and discharge of the fluidized product. The balance of the binder addition and drying rates is used in combination with fluidization (i.e., flow field) parameters to control the process. Balanced control of fluidization can be challenging in the context of micronized powders, prone to elutriation, for example as required in some pharmaceutical formulations. This manuscript explores the effects of thermodynamic and flow field parameters on the size and shape distributions of a challenging pharmaceutical formulation. Pre-wetting the powder mixture prior to fluidization effectively reduces elutriation, stabilizes the fluidization process, and results in narrower granule size distributions. Optimizing blowback pressure can further stabilize the process. These strategies contribute to improved control of fluidized bed granulation, particularly for challenging pharmaceutical formulations, enhancing both product quality and process efficiency.</p><p dir="ltr">A regime map for a challenging pharmaceutical formulation was developed to link operational parameters to granule characteristics, establishing a stable processing space that connects moisture gain with particle size and shape distributions and uniformity. This comprehensive framework supports scale-up and reliable application of fluid bed granulation in pharmaceutical and related industries, contributing to improved process efficiency and product quality. The findings presented here advance the scientific understanding of toroidal fluid bed granulation and offer practical and actionable strategies for controlling this process.</p>