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Abstract CO2-water drainage relative permeability is usually measured in laboratory using a three-stage unsteady-state flooding on cores. This three-stage flooding involves injecting water, then CO2-saturated water, and finally water-saturated supercritical CO2. The injection of CO2-saturated water has been previously found to generate fines due to mineral dissolution. The generated fines can flow with injected fluids and cause pore blockage. This paper examines the effect of fines migration and mineral reactions on CO2-water drainage relative permeability measurements, using a sintered glass core and eight Berea sandstone cores. Three-stage and two-stage flooding are performed on the cores. Three-stage flooding sequence is same as literature. Two-stage flooding involves injection only of water and then water-saturated CO2, to avoid the chemical reactions brought about by CO2-saturated water injection and thereby reduce mineral reactions. Pressure difference across the cores and volumes of water produced are recorded. These data are used to generate CO2-water drainage relative permeability functions. Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) analysis of the produced water and Scanning Electron Microscopy (SEM) images of the cores confirm mineral reactions occurred during CO2-saturated water injection in Berea cores. For Berea cores, CO2 relative permeability is reduced (by 21%–48%) during three-stage flooding when CO2-saturated water is injected. The reduction in CO2 relative permeability is found to be a function of water salinity and pore volumes of CO2-saturated water injected. Experiments performed on the glass core suggest that the error in CO2 relative permeability caused by the absence of CO2-saturated water is negligible. Therefore, we propose that CO2-saturated water be omitted during CO2-water drainage relative permeability measurements.

Human induced climate change will, in many parts of the world, create additional pressure on water supply systems. It is therefore vital for water resources managers to understand likely changes in future water availability. The only way of quantifying these changes is to use the outputs of General Circulation Models (GCMs). Due to time and resource limitations, it is often not possible to use the full suite of GCMs for which data is available. To decide which GCMs to use, it is necessary to evaluate the models with respect to their intended application. Following evaluation, corrections to GCM outputs may be required so that they match observations better. This thesis presents methods that can be used to evaluate and enhance GCM simulations for water resources impact assessments. For the purposes of evaluating GCM simulations, the thesis presents four techniques and case studies. The first, known as the Variable Convergence Score (VCS), compares the reliability of different climatic variables across time and space. It is developed for Australia to demonstrate that there is little confidence in precipitation projections for the future, compared to temperature and pressure projections. The VCS is also used globally to identify the reliability of GCMs for different regions. The third evaluation assesses the ability of GCMs to represent observed trends in pan evaporation. It is found that many of the GCMs do not capture the observed changes. Uncertainty in future projections is introduced by variability in vapour pressure deficit and wind speed. Finally, the modelling of variability on multiple time scales is investigated using a wavelet based skill score to assess the representation of large scale climate modes in GCMs. Methods to enhance GCM outputs are developed in the second part of the thesis. A Nested Bias Correction method is developed to post-process GCM simulations so that they are representative of observations across a range of time scales, achieved by matching the distributional and persistence attributes of the GCM and observed time series. The Nested Bias Correction method is applied to assess changes in future water availability across Australia. The bias correction approach is also compared to simple scaling approaches to demonstrate the importance of correcting for low-frequency persistence.

MXenes, a fresh family of 2D carbides and nitrides of transition metals, have garnered tremendous research interest over the past decade owing its unique combination of massive metallic conductivity and hydrophilicity. This graphene-like 2D material with its flexibility to morph into the form of membranes and thin films makes them suitable for a number of applications including supercapacitors, batteries, water purification and gas separation. Nevertheless, the high oxidation potential and a complex etching process limits the commercialization of MXenes. This thesis seeks to explore the performance of Ti3C2Tx MXenes for two important but diverse applications of energy storage and water purification. Firstly, thin film MXene electrodes were prepared and tested for their electrochemical performance in a three-electrode cell. Several characterization techniques were performed to analyse the chemical composition, structure, morphology and surface area of the MXene samples. Some key findings include the oxidation of delaminated Ti3C2 MXene into anatase when stored at normal room temperature conditions and high equivalent resistivity of the MXene electrode as a result of oxygenated functional groups. A high specific capacitance of ~127 F/g was obtained via cyclic voltammetry at a scan rate of 0.5 mV/s indicating its use as electrodes in supercapacitors. Secondly, MXene membranes were synthesized using the vacuum filtration method and tested for water flux and salt rejection. The membrane exhibited a hydrophilic character with a contact angle of 60˚ and its interlayer spacing was found to approximately increase from 9 Å to 13.5 Å due to the hydration effect. The pressure-driven filtration test indicated a high water flux of 307 LMH at 80 kPa and the membrane was able to permeate more than 90% ions as a result of size exclusion effect of the ion size and the interlayer spacing.

To reduce fine particulate matter emission from coal burning sources especially fossil fuel fired energy generation facility is critical to improve air quality. Attapulgite suspension was attempted to spray in a 6 kW fluidized bed facility and reduce fine particulate matter emission during coal combustion. The key parameters such as attapulgite mass, flowrate and spraying zone were investigated to determine the optimal and critical conditions that influence fine particulate matter emission. Exciting results indicate that both fine particle number and mass concentrations are largely decreased due to the physical/chemical absorption with the suitable mass ratio of 3 wt%. The spray of attapulgite suspension in both dense bed and dilute bed effectively mitigates fine particle emission based on the agglomeration and absorption. The most excellent result is achieved at a flowrate of 38 ml/min in dense bed with particle number reduction up to 93.5% in PM2.5 (fine particles is equal to/less than 2.5 μm), 93.6% in PM1.0 (fine particles is equal to/less than 1.0 μm) and 93.7% in PM0.1 (fine particles is equal to/less than 0.1 μm), respectively. The work highlights the potential of spraying attapulgite suspension as an effective process to reduce fine particle emission during coal combustion in fluidized bed system.

AbstractMethodologies for the basin-scale evaluation of industrial-scale CO2 geological storage in saline aquifers can include the use of analytical tools, generic reservoir simulations, as well as basin-specific flow modelling studies. The selection of appropriate tools is dependent on the scale of investigation. Comparison of the results from these methods for the assessment of basin-scale CO2 geological storage in the Gippsland and Otway basins in Australia suggests that, at this scale, a combination of analytical tools in the form of equations for calculating injection pressure, radius of impact and storage capacity with generic numerical simulations may provide useful first-order predictions for storage capacity and injectivity. However, the development of multiple resources (petroleum, groundwater, coal) in the Gippsland Basin and regional compartmentalisation in the Otway Basin necessitates an additional, coarsely discretised basin-scale numerical model.

Mass transport phenomenon was first recognized by Stokes in 1847 using a Lagrangian description. Later, a basic theory for the mass transport in water waves in viscous fluid and of finite depth was derived by Longuet-Higgins in 1953. Theoretical solutions of mass transport in progressive waves of permanent type are subjected to the definitions of wave celerity in deriving the various finite amplitude wave theories. As it has been generally acknowledged that the Stokes wave theory can not yield a correct prediction of mass transport in the shallow depths, some new theories have been developed. Recently the authors(1974 § 1977) have derived a new finite amplitude wave theory in shallow water for quasi- Stokes and cnoidal waves by the so-called reductive perturbation method, in which the mass transport is formulated both in Lagrangian and Eulerian descriptions. On the experimental verification, Russell and 0sorio(1957) investigated and compared Longuet-Higgins' solution with experimental data of Lagrangian mass transport velocity obtained in a normal closed wave tank of finite length. Since then, many investigations, and nearly all of them, have employed the finite length of wave tank in carrying out their experiments. However, no experiment has yet been attempted at verifying the Stokes drift in progressive waves of permanent type in a wave tank of infinite length. It is not realistic nor economical in constructing such an infinitely long flume to investigate experimentally the mass transport velocity in progressive waves. Instead of using such an ideal wave tank, a new one incorporated with natural water re-circulation was equipped to carry out experiments by the authors(1978). It was confirmed from these experiments that mass transport in progressive waves of permanent type exists in the Same direction of wave propagation throughout the depth, and agrees with both the Stokes drift and the authors' new formulations, within the test range of experiments.