No description available.

Gasification is a flexible technology which is applied in industry for electricity generation, hydrogen production, steam raising and liquid fuels production. Furthermore, it can utilize one or more feedstocks such as coal, biomass, municipal waste and petroleum coke. This versatility, in addition to being adaptable to various emissions control technologies (including carbon capture) renders it an attractive option for years to come. One of the most common gasifier types is the entrained-flow slagging gasifier. The behaviour of inorganic fuel components in these gasifiers is still ill-understood even though it can be the determining factor in their design and operation. A literature review of inorganic matter transformation sub-models for entrained-flow slagging gasifiers is provided. Slag viscosity was identified as a critical property in the sub-models. Slag viscosity models are only applicable to a limited range of slag compositions and conditions, and their performance is not easily assessed. An artificial neural network model was developed to predict slag viscosity over a broad range of temperatures and slag compositions. Furthermore, a toolbox was developed to assist slag viscosity model users in the selection of the best model for given slag compositions and conditions, and to help users determine how well the best model will perform. The slag viscosities of coal, petroleum coke and coal/petroleum coke blends were measured in the temperature range of 1175-1650ºC. Interaction of vanadium-rich slags with various materials was investigated. The results from the first two parts of a three-part research program which involves fuel characterization, testing in a 1 MWth gasifier, and computational fluid dynamics (CFD) modeling for entrained-flow slagging gasification are presented. The end goal is to develop a CFD model which includes inorganic matter transformations. Fuel properties were determined with prioritization based on their application; screening of potential fuels, ensuring proper gasifier operation, gasifier design and/or CFD modeling. Using CanmetENERGY’s 1 MWth gasifier, five gasification tests were completed with the characterized coals. Solid samples from the refractory liners, in-situ gas sampling probe sheaths and impingers, the slag tap, the slag pot, quench discharge water and scrubber water were collected and characterized.

Tang, Xiaoju. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 66-71). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Sun Siu-wing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 50-51). / Abstracts in English and Chinese. / Acknowledgments --- p.i / Abstract --- p.ii / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Equation without viscosity --- p.5 / Chapter 3 --- Equation with standard viscosity --- p.8 / Chapter 3.1 --- "Particular convective flux, f(x) =u2" --- p.8 / Chapter 3.2 --- Convex convective flux --- p.10 / Chapter 4 --- Equation with monotonic dissipative flux --- p.11 / Chapter 4.1 --- Large initial data --- p.12 / Chapter 4.2 --- Small initial data --- p.19 / Chapter 4.3 --- Unbounded dissipative flux --- p.28 / Chapter 5 --- Equation with non-monotonic dissipative flux --- p.31 / Chapter 5.1 --- Large initial data --- p.32 / Chapter 5.2 --- Small initial data --- p.37 / Chapter 6 --- Comparison and conclusions --- p.39 / Appendices --- p.42 / Chapter A --- Hopf-Cole transformation --- p.42 / Chapter B --- Dirichlet problem --- p.45 / Bibliography --- p.50

The viscosity of Zr[subscript 41.2]Ti[subscript 13.8]Cu[subscript 12.5]Ni[subscript 10.0]Be[subscript 22.5] (Vit1) has been measured above the liquidus temperature, T[subscript liq]=1026 K, using a high vacuum high temperature rapid annealing furnace equipped with a Couette Concentric Cylinder Rheometer. Steady state measurements have been taken over a temperature range of 1075-1300 K and a shear rate range of 10⁰-10² s⁻¹. It has previously been discovered that there exists a pronounced decrease in viscosity with increasing shear rate which is contrary to the general belief that metallic systems above the liquidus temperature should show Newtonian behavior due to high atomic mobility. This suggests that there is short or medium range order present in the liquid state that can be destroyed by shearing. This current study has discovered that this shear rate dependence of the viscosity of Vit1 decreases with increasing temperature and approaches the Newtonian behavior and viscosities of simple monatomic or binary liquid alloys at 1225 K. Once this state is reached the viscosity will remain Newtonian in the liquid state and no order is reformed until the sample is cooled into the supercooled region. This indicates a strong temperature history dependence of the viscosity. It has also been discovered that initially crystalline Vit1 has an order of magnitude lower viscosity than initially amorphous Vit1 at 1075 K after melting. This difference decreases with increasing temperature until similar viscosities are obtained at 1175 K. The Vogel-Fulcher-Tammann relationship shows decreasing fragility of Vit1 with increasing shear rate and increasing temperature. It was also seen that temperature has a larger and more permanent effect on the fragility than shear rate. The development and results of converting viscosity data to configurational entropy using the Adam-Gibbs entropy model for viscous flow are discussed. This shows that the configurational entropy present after melting is on the order of the entropy of fusion. / Graduation date: 2006

Gasification is a flexible technology which is applied in industry for electricity generation, hydrogen production, steam raising and liquid fuels production. Furthermore, it can utilize one or more feedstocks such as coal, biomass, municipal waste and petroleum coke. This versatility, in addition to being adaptable to various emissions control technologies (including carbon capture) renders it an attractive option for years to come. One of the most common gasifier types is the entrained-flow slagging gasifier. The behaviour of inorganic fuel components in these gasifiers is still ill-understood even though it can be the determining factor in their design and operation. A literature review of inorganic matter transformation sub-models for entrained-flow slagging gasifiers is provided. Slag viscosity was identified as a critical property in the sub-models. Slag viscosity models are only applicable to a limited range of slag compositions and conditions, and their performance is not easily assessed. An artificial neural network model was developed to predict slag viscosity over a broad range of temperatures and slag compositions. Furthermore, a toolbox was developed to assist slag viscosity model users in the selection of the best model for given slag compositions and conditions, and to help users determine how well the best model will perform. The slag viscosities of coal, petroleum coke and coal/petroleum coke blends were measured in the temperature range of 1175-1650ºC. Interaction of vanadium-rich slags with various materials was investigated. The results from the first two parts of a three-part research program which involves fuel characterization, testing in a 1 MWth gasifier, and computational fluid dynamics (CFD) modeling for entrained-flow slagging gasification are presented. The end goal is to develop a CFD model which includes inorganic matter transformations. Fuel properties were determined with prioritization based on their application; screening of potential fuels, ensuring proper gasifier operation, gasifier design and/or CFD modeling. Using CanmetENERGY’s 1 MWth gasifier, five gasification tests were completed with the characterized coals. Solid samples from the refractory liners, in-situ gas sampling probe sheaths and impingers, the slag tap, the slag pot, quench discharge water and scrubber water were collected and characterized.

No description available.

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Viscosity is an important parameter in fluid dynamics. Although many conventional techniques are useful in determining a limited range of liquid viscosity with high accuracy, non-invasive measurement techniques for a broader range of viscosity are yet to be developed. The subjects on viscosity are advancing rapidly partly due to the development and applications of microfluidic. In anticipation of such developments, we are proposing a new method of viscosity measurement in the micrometer scale that is simple, non-invasive, real-time, wide dynamics range, and with imaging capability. This method relies on successful integration of laser scanning confocal microscopy, lock-in amplification, and variable galvono-scanning. It also has the potential to be a powerful tool in biology and medicine. The principle of operation is based on modulation microscopy that employs confocal configuration in detecting the deformation and phase delay of the forced oscillating sample.