Currently, an increasing price in petroleum and depleting its resources has created a new interest in the synthesis of liquid fuels from natural gas by Fisher Tropsch (FT) synthesis. In FT synthesis, natural gas is converted to multi-component mixture of hydrocarbons whereby Computational Fluid Dynamics (CFD) is a tool to predict the behaviour of fluid flow, heat and mass transfer and chemical reaction in the FT reactor. Slurry phase FT reactor is selected because of its advantages over the fixed bed system in term of heat transfer, minimization of hot-spots and side reaction, and better catalyst longevity. However, the behaviour of slurry phase FT reactor is not well understood. The purpose of my research is to develop CFD model that can describe and predict experimental data over a wide range of industrially-relevant conditions for continuous slurry FT operation.

Synthesis gas production from the dry reforming of hydrocarbons has received considerable interest in recent literature because it yields relatively lower H₂:CO ratio (<2) than other syngas production routes and therefore well-suited to downstream usage in the production of clean fuels from GTL processes and olefin-rich feedstock for the petrochemical industries. The attendant reduction in overall green-house gas emission due to CO₂ consumption is a further advantage of the dry reforming route. The reaction is typically carried out over a Ni catalyst but accompanying carbon deposition often leads to deactivation and pathological reactor operation. The study focuses on the investigation of the deactivation process taking place concurrently with dry reforming reaction of propane and enhancing the research in clean fuels and synthesis gas (syngas) production by examining Ni-based catalyst at different metal loadings. In addition, part of this research is to perform a kinetic study on the reaction. To achieve the aims of this research, the following reaction CO₂ reforming:CO₂ + C₃H₈ = 6 CO + 4 H₂ will be tested using Ce-Co-Ni/Al2o3 catalyst. Thus, the project covers: 1- Catalyst Evaluation. 2- Kinetics Analysis. 3- Reactor Operation.

Synthesis gas production from the dry reforming of hydrocarbons has received considerable interest in recent literature because it yields relatively lower H₂:CO ratio (<2) than other syngas production routes and therefore well-suited to downstream usage in the production of clean fuels from GTL processes and olefin-rich feedstock for the petrochemical industries. The attendant reduction in overall green-house gas emission due to CO₂ consumption is a further advantage of the dry reforming route. The reaction is typically carried out over a Ni catalyst but accompanying carbon deposition often leads to deactivation and pathological reactor operation.

The study focuses on the investigation of the deactivation process taking place concurrently with dry reforming reaction of propane and enhancing the research in clean fuels and synthesis gas (syngas) production by examining Ni-based catalyst at different Ce and Co loadings. To achieve the aims of this research, the CO₂ reforming reaction:

CO₂ + C₃H₈ = 6 CO + 4 H₂

will be carried out in both fixed and fluidized bed reactors. Thus, the project covers:

1- Catalyst Evaluation

2- Kinetics Analysis

3- Reactor Operation

Increasing crude oil prices and a global awareness of depleting resources has encouraged research into alternative sources of energy. Of the various avenues being considered, the gas-to-liquids conversion of synthesis gas (CO + H₂) derived from coal gasification or stranded gas fields, to Clean Fuels via Fischer-Tropsch (FT) Synthesis has a most promising future, as it demands minimal change of current infrastructure. FT products are a valuable source for sulfur-free gasoline and diesel range hydrocarbons, as well as high molecular weight waxes and feedstock for specialty chemicals.

From a commercial standpoint, the Slurry Phase Bubble Column Reactor holds the future to FTS, due to its significant advantages over the Fixed Bed and Fluidised Bed Reactor families, including lower pressure drop, isothermal operation, minimisation of hot-spots, reduced catalyst deactivation, overcoming diffusion limitations, and a potential for continuous catalyst replenishment/regeneration. While catalyst deactivation still remains a major area of concern for FTS, research and development of novel multi-metallic catalyst formulations has demonstrated capabilities for enhanced catalyst reducibility, activity, and product selectivity. In recent years, oxide supported cobalt has been the preferred choice for a commercial catalyst, due to its high activity, better selectivity to higher hydrocarbons, and low conversion to CO₂, compared to iron catalysts, however suffer from carbon-induced deactivation. Since Mo carbide is known to possess activity towards hydrogenation/dehydrogenation reactions, and is routinely used as a hydrodesulfurisation (HDS) catalyst, the addition of Mo to a Co catalyst should endow it with carbon-resilient properties, especially for sulfur-containing coal and natural gas conversion processes. Consequently, this project aims to study the bimetallic Co-Mo system, in terms of its activity and selectivity, and to elucidate the prevailing mechanism on the catalyst surface through kinetic modeling, and ultimately evaluate its potential for application to slurry phase Fischer-Tropsch synthesis in a continuous stirred tank slurry reactor.

Reactor performance, reactor hardware and operating protocols are inter-related by fluid dynamics. Fluid dynamics of a process reactor strongly influences the scale-up and design of the reactor before implementation in the industry. Industrial processes such as biological wastewater treatment and fermentation utilise bubble column and fluidised bed reactors for which scale-up and design is found to be complex and difficult thus limiting improved the reactor performance. Consequently, there is a compelling need to understand the hydrodynamics and predict the performance of multiphase flow reactors. The purpose of my research is to implement computational fluid dynamics (CFD) analysis for the investigation of the flow characteristics and prediction of the performance of these reactors. Validation will be carried out in a non-invasive manner using tomography techniques analogous to medical imaging methods. While CFD code is used to predict the performance of a system before implementation, tomography validates the code by providing data that characterize the parameter distribution within large flow domains at the same time as the system is functioning. Tomography not only monitors the process but also obtains information and control by intervening during operational stages using on-line and off-line measurements. The use of tomography would greatly assist in improving product yield and uniformity, minimising input process material, reduce energy consumption and lower occupational exposure to plant personnel. In this research, Electrical Resistance Tomography (ERT) is applied to gas-liquid contactors and conductivities of liquid and gas-liquid mixture are used to derive mass transfer parameters such as gas hold-up and bubble size distribution.

The increased interest in biodiesel production for green energy generation is driving the research for fatty acid alkyl ester (FAAE) synthesis via transesterification and esterification. The present study deals with the in-depth kinetic investigation of the FAAE synthesis based on ethanolic esterification of oleic acid (a common component of most oils) using immobilised lipase in a slurry reactor. The character of the reaction in both micro-aqueous and biphasic media are sought. Equilibrium data will also be collected and combined with kinetic rate models to develop rate-temperature-conversion profiles. In the final stage of the work, experiments will be carried out in a basket-impeller catalytic distillation column to optimise biodiesel production rates which will transcend the thermodynamic limitations and enhanced mass transfer efficiency leading to superior product quality.

My research interests are in the area of Gas – To – Liquid (GTL) technologies, specifically at converting natural gas into liquid fuels. Australia is blessed with abundant natural gas especially in the NW Shelf and Bass Strait. However, most of the natural gas is stranded offshore and cannot be recovered economically without onsite gas-to-liquid processes. Transition metal carbides are being developed and investigated for the direct conversion of natural gas to gasoline-range hydrocarbons in a variety of multiphase reactors. As a result, I am also interested in the analysis of these reactors using tools of process tomography. Our laboratory is equipped with new electrical tomography facilities for system characterisation and process optimisation.