Postgraduate Chemical and Process Engineering

Research focused on applying fundamental microbiological research to a range of biotechnologies that address goals relating to global issues, such as public health, food production, water security, energy independence and environmental sustainability.

Design of low-energy gas and vapour separation processes

The petrochemical industry primarily uses distillation to separate complex hydrocarbon mixtures and chemical precursors. Estimates put the separations at 10-15% of global energy use. My overall vision is to provide low-energy solutions to these separation challenges. My background is in fundamental chemistry, materials science, and separations engineering—so projects will be diverse, wide in scope, and application focused. Candidates interested in developing multi-disciplinary experimental and collaborative skill-sets are the best fit for this research group.

Membrane separation of alkane-alkene gas pairs

The similar size of alkane-alkene gas pairs makes them difficult to separate using membrane technology. Approaches being considered include: polymeric facilitated transport, mixed-matrix, and inorganic membranes. Projects will involve the preparation of new membrane materials, design of equipment to evaluate properties relevant to industrial gas separations, and development of new process designs to take advantage of new materials.

Pressure and temperature swing adsorption processes for alkane-alkene gas pairs

Pressure and temperature swing processes are widely used in industry for the separation and purification of industrial gases. Research projects in this area include: the informed design of new adsorbent materials, fundamental understanding of adsorbent properties, process design and modelling, and construction of prototype equipment.

3D-Printed Porous Media for Chromatography

I am seeking innovative and well-prepared students with a background in chemical engineering or related fields to take on projects in the area described below.

Our group was the first in the world to propose and demonstrate the concept of printing highly-ordered porous structures with finely controlled geometries for use in chromatography, catalysis, filtration and other areas where fluid-solid contact is important. Our first publication in the area (Fee C.J., Nawada S. and Dimartino S. (2014) “3D Printed Porous Media Columns with Fine Control of Column Packing Geometry”, J. Chromatography A Vol.1333, 18-24) describes the concept of producing these, including printing the entire column, internal flow distributors and fluid fittings, etc, in one integrated piece. We now have a large number of active researchers on our team from chemical engineering, mechanical engineering, physics, mathematics, computer science and chemistry, investigating a wide range of topics.

I am seeking people to work in this highly relevant and exciting area. In particular, there are projects in the areas of:

• New packing geometries from an experimental design-print-build-test point of view, using our existing 3D printers and AKTA chromatography systems, amongst other instruments such as microCT scanning to test internal geometry (would suit a chemical engineering or similar background)
• Computational fluid dynamics (CFD) using the Lattice-Boltzmann method and our BlueGene supercomputer to extend our own current implementation of the Palabos Software to simulate flow through various novel geometries, and to model performance in chromatographic processes including convection, diffusion and adsorption (would suit any relevant engineering, physics or mathematics backgrounds)
• Materials development, including both highly porous organic polymers and hydrogels to optimize their internal pore characteristics and strength when printed using various approaches (would suit chemical, materials or polymer engineering or chemistry backgrounds)
• New printer developments for printing a variety of materials (organic, inorganic, ceramic, hydrogels, polymeric) suitable for use in porous beds (would suit mechanical or mechatronics engineering backgrounds)
• Counter-current extraction techniques using novel 3D-printed packing geometries (would suit a chemical engineering or similar background)
• Bioreactor development using immobilized cells, enzymes of other biocatalysts in printed porous beds (would suit a chemical engineering or similar background)
• Geometric analysis and optimization of flow, adsorption and transport through novel 3D-printed geometries (would suit a mathematics background)
• Surface modification to functionalize 3D-printed hydrogels and organic polymers for adsorption and/or catalysis (would suit organic chemistry or chemical engineering backgrounds)

Biofiltration

Biofiltration is an air pollution control technology widely used in New Zealand and around the world. It is mainly used for treating high flow rate air streams contaminated with low concentrations of organics (<1000 ppmv). It is especially useful for treating odorous air streams. In this technology, the contaminated air passes through a packed bed reactor filled with biologically active media such as compost or soil. The organic contaminant partitions into the natural biofilm and the organisms present oxidise the organic, producing carbon dioxide and water. While biofilters are rather easy to build, they can be very difficult to operate successfully. This is due to a poor understanding of the engineering aspects of the system such as air and water flow, energy balances and proper control of key parameters.

a) Water Content Effect on Microbial activity – ME/Ph.D.

The water content and water potential can vary dramatically in biofilters. These variations theoretically affect both the intrinsic bioactivity and the mass transfer in these systems. No systematic study has been performed on how changes in water content and potential affect the specific activity of biofilter media. A novel bioreactor configuration that has been designed and built at Canterbury for these types of measurements. It allows very accurate control over the water potential, providing far more detailed information on microbial activity in gas phase bioreactions than has been available in the past. This information is required in conjunction with the air and water flow properties to optimize the proper media and water content for biofilter operation.

b) Impact of metabolic uncouplers on biofiltration

Metabolic uncouplers interfere with ATP production. The hypotheis is they could raise the elimination capacity for biofilters. They have been tested in activated sludge systems to lower the sludge yield with mixed success. However, biofiltration is a much more appropriate technology to implement these chemicals as they are not released with the water. This project will test this hypothesis with different uncouplers and different biofilter systems.

Microbial Cellulose Production – ME/Ph.D.

Cellulose is normally derived from trees and is the main constituent of paper. However certain strains of bacteria excrete cellulose as an extracellular polysaccharide. This cellulose is relatively pure and does not contain the lignin and hemicellulose associated with wood. Its other unique property is that the chain length is much longer and thereby produces much stronger paper. Its uses include high quality speaker cones and headphones and it has novel features as a wound dressing. At present, microbial cellulose is commercially made in low-tech surface cultures but it also has been made with rotating biological contactors (RBC). This project will continue to evaluate new reactor configurations for producing microbial cellulose. These reactors will be designed to optimise different aspects of production or the end product.  

Microbial Fuel Cells – ME/Ph.D. (in conjunction with Aaron Marshall)

Microbial fuel cells have been coupled with waste water treatment for energy production. This project will investigate their potential in contaminated air applications.

Research interests in the area of mathematical modelling and optimisation of chemical processes, immersive learning applications and the implementation of information technology tools into the chemical and process engineering curriculum.

Research in the design, simulation, and build of imaging systems or various image processing techniques to overcome blurring effects caused by the Earth’s atmosphere to aid in the observation of astronomical objects, satellites, and space junk.

Fundamentals of gas-solid flow

Gas-solid flows are found in a variety of industries ranging from the production of milk powder and fertilisers to electrical power generation. However despite their widespread use, processes relying on gas-solid flows are notoriously difficult to design and operate efficiently. Numerical simulation techniques can potentially aid the design of new processes. However, the numerical simulation of gas-solid flow is challenging because of the vast range of time and length scales that govern the overall flow.  For example, microscopic collisions between particles govern the apparent “viscosity” of the particulate phase and thus the motion of every individual particle should be modelled in order to accurately describe the flow. However, such a method is impractical when describing an industrial scale system.  Recently magnetic resonance imaging has been shown to be effective for measuring the motion of particles in simple gas-solid flows. This project will use these measurements to study how the motion of individual particles relates to the apparent viscosity of the granular flow. On the basis of these measurements, we will develop a rheological model that is suitable for describing macroscopic, industrial flows.

High resolution electrical tomography

Electrical tomography is a non-invasive imaging technique that can be used to study the distribution of material in multiphase flows. It has been widely used to study gas-solid, gas-liquid, liquid-liquid, and liquid-solid flows. To date, measurements have been restricted to relatively low spatial resolutions owing to the diffuse nature of the electrical field variation. This project seeks to develop complex electrical excitation patterns that will increase the spatial resolution that is achievable with electrical tomography. Such an approach will need to exploit recent developments in signal processing, including compressed sensing to enable the measurements to be obtained in experimentally relevant time scales.

Formulation of fertilisers

The development of fertilisers has enabled dramatic increases in the productivity of agriculture. However, the application of excess amounts of fertiliser leads to eutrophication and degradation of our waterways. Considerable effort goes into ensuring that fertilisers are formulated in such a way that the nutrients are released at the right time and place. For example, granulated fertilisers are commonly used to facilitate easy handling and distribution, whilst for certain crops fertilisers may be coated in polymers or sulphur compounds to ensure that the release of the active species occurs gradually. This project will seek to develop imaging and numerical modelling techniques to explore the formulation of fertilisers and how this affects the rate of release of the active chemicals.

Understanding the Electrocatalytic behaviour of conductive metal oxides: The role of potential induced structural changes

RuO2 and IrO2 are important electrode materials as they exhibit high electrocatalytic behaviour for many industrial processes. These conductive metal oxide electrodes are unique and exhibit quite different behaviour compared to the convectional understanding derived from metallic electrodes. In addition to their excellent electronic conduction, these oxides can also conduct protons. This is accompanied by potential dependent proton exchange between the oxide and the electrolyte in conjunction with oxidation or reduction of the metal within the oxide. This phenomenon causes the metal-oxygen bond length to vary with potential, thus directly altering the structure of the electrode-electrolyte interface via a geometric mechanism as well as the normal electronic mechanism. This ability of the oxide to undergo these structural changes (e.g. oxidation state, M-O bond length) has been identified as the critical factor in determining their electrocatalytic activity. Despite this, a lack of direct experimental evidence has hampered a conclusive theory being established. We will use various techniques like electrochemical quartz crystal microbalance, Raman spectroscopy, AFM and in-situ x-ray absorption spectroscopy to study these structural changes as a function of electrode potential at various electrocatalytic oxides. This will provide useful information for improving our knowledge of these electrocatalysts.

Optimisation of catalytic layers for Hydrogen production in PEM water electrolysers

PEM water electrolysers, utilise porous catalytic layers in which the electrochemical reactions occur. These porous layers are a composite of electrocatalytic nanoparticles and solid polymer electrolyte. Optimising the structure of the catalytic layer is a critical step to improving the performance and energy efficiency of the electrolyser. These layers must possess high electrical, ionic and mass transport in order to maximise the electrolyser efficiency. We are particularly interested in assessing how lateral conductivity influences cell performance. Furthermore, layer optimisation may lead to a decrease in the quantity of expensive catalyst required to support the electrode reactions.

Development and optimisation of microchannel reactors using electrochemical processing

Microchannel reactors are used in a variety of processes where high heat and mass transfer rates are required. Recently we have explored the preparation of microchannels in both aluminium and stainless steel substrates by using electrochemical etching. This technique allows full control over the etching rate and the resulting channel morphology. We wish to extend this study to explore the electrochemical and electrophoretic deposition of porous catalytic materials within these channels. The process of forming the channels and deposition of the catalyst will studied using electron microscopy, XRD and gas adsorption. Once prepared, these reactors will be utilised for reactions like the water-gas-shift reaction, selective CO oxidation, or Fischer- Tropsch synthesis.

Hydrogen production by the electrochemical oxidation of glycerol

Glycerol is a by-product of the continuously expanding bio-diesel industry. Recently we have demonstrated that hydrogen can be produced from glycerol using significantly less electrical power than traditional water electrolysis. The purpose built electrochemical reactor uses similar technology to that used in PEM fuel cells with the reaction occurring on a thin layer of catalytic nanoparticles. The overall objective of this project is to develop novel catalytic nanoparticles to increase the reaction kinetics. Of particular importance will be the selectivity and the degree of reaction completion each catalyst can achieve. The catalytic nanoparticles will be characterised using standard electrochemical methods, electron microscopy and various synchrotron based x-ray techniques. Students interested in catalysis, fuel cells, hydrogen energy or materials science should apply.

Electrochemical conversion of CO2 to methanol

Efficient conversion of CO2 into liquid fuels such as methanol has the potential to “revolutionise green energy technologies”. This would solve many of the challenges associated with utilising renewable energy sources by providing carbon-neutral energy storage. CO2 can be converted to methanol by electrochemical reduction, although there are significant challenges which must be overcome before this technology is economically viable. Specifically, despite electrochemical reduction of CO2 having surprisingly low thermodynamic energy requirements, (methanol from CO2 requires ~20 mV less than that for H2 production via water electrolysis), large activation barriers substantially increase the energy demands of the process. These activation barriers are mainly caused by the instability of the adsorbed formyl intermediate and can be overcome by well-designed electrocatalysts. The project will involve preparing this electrodes and testing the performance in a lab scale reactor.

Electrochemical wastewater treatment

Electrochemical wastewater treatment offers a robust and controllable method of treating wastewater which is difficult to treat using traditional biological processes. This project will explore the use of electrodes in which nanoparticles are embedded into an oxide matrix. These electrodes offer enhanced surface area, unique reactive boundary zones as well as heterogeneous electronic properties (semi-conducting particles in metallically conductive matrix). The energy and current efficiency for industrial wastewater treatment as well as the degradation kinetics and mechanism of a model wastewater at these electrodes will be examined.

Ken Morison welcomes any research proposals that use the skills of chemical and process engineering to solve problems of the food and dairy industries.

Ion activities in dairy liquids

The behaviour of minerals and proteins in milk and other dairy liquids depends on the thermodynamic activities of the ions and ion-pairs.  These influence pH and hence solubility and protein charge. This project will continue to explore fundamentals of activities especially in concentrated liquids with a view to predicting some of the functional properties of milk. The project requires mathematical modelling and simulation, as well as careful experimentation.

Reverse osmosis of milk

A recent project on fouling and cleaning during reverse osmosis of milk showed that fouling in an industrial plant was quite different from fouling that was obtained in a lab. The mechanism for the difference was not determined. This project will start with lipid analysis and adsorption studies perhaps using a quartz crystal microbalance (QCM). The aim will be to determine suitable operating conditions for milk concentration and for cleaning of membranes.

Nanoparticle formation in dairy solutions

We have found that, in some conditions, the presence of lactose prevents precipitation of calcium and phosphate ions, but instead nanoparticles are formed. This is likely to be of importance in understanding the stability of calcium phosphate in milk and milk products. We will use bench chemistry and dynamic light scattering to develop repeatable methods and hence determine the range of conditions in which these nanoparticles are created.

Crystallisation from model solutions

Honey is a complex solution which is very variable and hence has a wide range of properties.  Some honey crystallises but the nature of the crystallisation is very difficult to predict.  Similarly lactose is crystallised from a complex mixture of lactose and milk salts after the whey proteins have been removed from whey by ultrafiltration.  Model solutions mimicking each will be created to determine the effects of composition, physical properties and activities on crystallisation and other properties.

Crystallisation from viscous solutions

The nature of crystallisation seems to be quite different when it occurs in viscous solutions such as honey. In this speculative project we will compare the growth of crystals in high and low viscosity systems and hence isolate the mechanisms of diffusion, alignment, crystallisation and mutarotation if applicable. We will seek to determine why crystal structure is dependent on fluid viscosity. This problem could be approached as an experimental or modelling project.

EPA from algae

A New Zealand algae has been found to produce high levels of EPA (eicosapentaenoic acid), one of the omega-3 fatty acids when grown under some conditions. In this project the biochemical pathways will be investigated so that ideal growth conditions can be developed.

Modelling of transport phenomena in 3-D printed geometries

3-D printing (or additive manufacturing) allows complex repeating structures to be created. Conventional simulation using CFD tools does not seem to suit this style of problem but instead the lattice Boltzmann approach does. A useful model will allow simulation of multicomponent flow, heat flow within the solid and fluid parts, adsorption and reactions. This project required a strong aptitude for computer programming together with a good understanding of the fundamentals of transport phenomena.

Dynamics of falling film flow in evaporator tubes

Ideal theoretical flow inside a falling film evaporator is often described as a uniform laminar film. In practice the flow is wavy, and is neither uniform in the radial and axial directions nor constant. Within the films there are velocity, temperature, concentration and viscosity variations. This project will require some detailed modelling and simulation of the film, together with experimentation to validate results.

Production of clean, hydrogen-rich syngas from gasification of biomass pyrolysis slurry – PhD

This project is part of the newly funded research programme to develop technologies for production of clean, hydrogen-rich syngas from gasification of biomass pyrolysis slurry. Development and construction of experimental apparatus will firstly be conducted on entrained flow gasification technology using biomass pyrolysis slurry, then cleaning technology will be developed to remove tars and sulphur. This project will be in collaboration with another PhD project of this research programme on biomass pyrolysis. A scholarship of $26,000 pa will be available for three years to the successful candidate.

Pyrolysis of biomass for liquid fuel and for slurry of bio-oil/char, ME/PhD

With the declining of fossil fuel reserves in the world, sustainable resources have been sought world-wide for production of alternative liquid fuels. This project is designed to use biomass to produce the liquid fuels and bio-oil/char slurry by pyrolysis process. A lab-scale pyrolysis reactor which has been designed and constructed in this department will be used in this research. A pilot scale pyrolysis reactor will be designed and constructed in this PhD project. Fundamental studies on the pyrolysis process, oil upgrading and slurry production will be the target of this project. This project will be in collaboration with another PhD project of this research programme on biomass slurry gasification. A scholarship of $26,000 pa will be available for three years to the successful candidate.

Exergy efficiency and life-cycle analysis sis for Fischer-Tropsch synthesis of bio-diesel from biomass - PhD

The objective of this project is to develop and construct a computer model for biomass to biodiesel via gasification and Fischer-Tropsh (F-T) process. The system of biomass to biodiesel is consisting of biomass production/collection, biomass pre-treatment (sizing, drying), biomass gasification, producer gas cleaning, gas upgrading and compression, F-T synthesis, F-T diesel separation and exhaust gas utilisation. The model will be used for exergy efficiency and life cycle analysis. The project will be based on previous feasibility studies of ‘biomass integrated gasification combined cycle’ for generation of power and heat, conducted in the same Department. It will be linked to the other projects in the same research programme including biomass resources and technology development on biomass gasification, pyrolysis and F-T synthesis. A scholarship of $26,000 pa will be available for three years to the successful candidate.

Drying of wood biomass - ME

In order to achieve high conversion efficiency and to improve the gas quality in the biomass gasification, the moisture content of the biomass feeding stock is required to be between 12 and 15%. However, the green chips from forest residues can have moisture content as high as 150%, while the fuel from a wood processing plant may have a much lower moisture content. This project is to develop new drying technologies and to optimise drying operations to achieve uniform moisture content. A ME scholarship will be available for this project at a rate of $22,000 p.a. for up to two years.

Wood-recycled plastics composite – ME

This project is to optimise operation conditions to produce stable and durable wood-recycled plastic composites used as new building materials. The product properties using both hot press moulding and injection moulding will be measured and compared. This project is aligned with an on-going PhD project on the development of the composite product and processing technology.

Recovery of heat and emissions from kiln drying of timber – ME

In commercial timber drying, fresh air is drawn in and exhaust air is vented out in order to maintain required humidity inside the drying kiln. This has raised two issues: one is the reduced heat efficiency due to the exhausted hot air and another is emissions which are vented with the exhaust air. Recently, the wood drying group in this department, in collaboration with a kiln manufacturer has initiated a research project on recovery of heat and emissions from kiln drying of timber. An experimental system has been built and is commissioned which will be used in this research project. This project will investigate the optimised operation conditions and recovery efficiency in different drying schedule. Wood quality of dried timber using this new drying system will be evaluated. The results from this project will be directly applied to development of new design of the timber kiln.

Development of new technologies for drying high quality softwood timber - ME

Timber from plantation forests has significant variability in wood quality which induces high proportion of rejection or downgrade due to drying defects. Among these defects are residual drying stresses, checking and discolouration. This project is to develop new drying technologies which will produce high quality timber with minimised cost and environmental effects. The project includes both fundamental modelling and experimental investigation. Preliminary research results on airless drying have shown numerous advantages and the project will start with, but not be limited to, superheated steam drying.

Reducing VOC emission in kiln drying of timber – ME

Kiln drying of wood emits hydrocarbon compounds which are released while the wood is dried. It is anticipated that in the foreseeable future, environmental regulations will be proposed which will place limits on the emission level and which the timber industry will have to comply with. This project will investigate the effects of drying schedule on the emissions from drying tests both in a laboratory and a commercial drying kiln. Studies will also be undertaken to see solutions: drying schedule optimisation and treatment of the exhaust air.

Production of Biochemicals from Wood as Substitues to Petroleum-derived Chemicals

This PhD project is to investigate the synthesis of biochemicals directly from wood during fast pyrolysis, as substitutes of present petroleum-derived chemicals. This is a new technology with limited prior published research available so there is an opportunity to break new ground. Scale up of successful research could lead to a wood based New Zealand chemical industry.

Research goal to develop advanced materials based on understanding of the “Structure-State-Property” relationship. The specific objectives to achieve the goal are:

(1) Synthesizing novel polymeric resins to give specific properties

(2) developing processes to produce polymeric products

(3) developing scientific instruments to characterize polymeric resins and products.

Overraching goal: identify economic ways to eliminate fossil fuels from heavy industry, optimise energy usage, and develop better processes for the circular economy.

Research interests:

• high-temperature electrolytic reduction of metals
• domestic production of maple syrup
• additive manufacturing of structured catalyst and adsorbent supports
• mineral extraction from domestic resources
• catalysis
• reactor modelling.

Endometriosis Disease Modelling

We have carried out focus groups looking at patient experiences (including specific Māori, Pasifika, and LGTBQIA+ focus groups). This helped us identify where the crucial focus of this research needs to be. Our lab uses endometriosis cell lines to characterise how the endometriosis cells invade surrounding tissue and the impact of the microenvironment on their invasive phenotype. This work is being carried out in collaboration with Michigan State University, Columbia University, Washington University in St Louis, University of Otago and Melbourne University. We are also developing 3D scaffolds and examining the impact of hormone dosing on the behaviour of endometriosis cells.

Neurological repair after spinal cord injury

This research involves the manufacture of nano-printed 3D cell scaffolds to guide neurons to regenerate in a directional manner. It also examines the impact of co- and multi-cell culture and the paracrine signalling required for healthy neuronal growth. It is hoped the physical and chemical cues can be combined to create an implantable scaffold to restore neural connection after a spinal cord injury.  

Skin mimics for dermal drug delivery testing

Currently drug delivery is assessed using pig skin. This is unfavourable due to the presence of animal testing required, as well as only providing the top layer for assessment. This research aims to develop a skin mimic that not only has the correct surface tension to mimic the skin, but also the flow of blood underneath. This flow brings drugs into the system so being able to test the absorbance of the drug and how long it stays in the system is crucial to understanding dermal drug delivery. We are focusing on how we can incorporate our current design into a larger network that accounts for blood flow.

Development of a novel “three-way” catalyst for hydrogen generation from water-gas-shift reaction.

Biomass resources have promising potentials to produce a hydrogen-rich syngas stream for the production of renewable H2. However, the high concentration of H2, as well as the presence of CO2, restrict the conversion of steam reforming and water-gas-shift (WGS) reactions. This 3-year Ph.D. project will develop a catalytic reaction system to enhance the production of H2 using a novel “three-way” catalyst at a high reaction temperature. The ultimate goal is to provide a unique possibility of hydrogen export for New Zealand.

We are looking for an excellent candidate to fill this Ph.D. position. Strong candidates with a background in chemical engineering, chemistry or physical chemistry, and those who have an interest in catalysis should apply. The candidates require a bachelor’s (honours) degree with first-class honours to be eligible for consideration. 

Strategies for zeolite synthesis by design

Currently, zeolites are used for a vast array of applications, from cat litter and laundry detergent to solid acid catalysts for gasoline production. The critical attribute of zeolites is the variety of cavity and pore sizes to trap molecules and/or carry out chemical transformations. The main problem with current technologies to synthesize zeolites is the minimal shape control of the pores and cavities, which reduces the possibilities for selectivity in chemical transformations and molecular capture processes. This research aims to introduce high-precision control of cavities and pores in zeolites using specially made structure-directing agents (SDAs) and identify corresponding catalytic reactions. Correlations between the SDAs type, porosity, crystallinity, pore size distribution, and zeolite surface area will be investigated.

Design of heterogeneous catalysts with dual active sites for higher alcohol synthesis

The synthesis of higher alcohols, which are useful chemical feedstock intermediates, from carbon monoxide hydrogenation is an attractive research area in recent years. In the bimetallic catalyst, one metal dissociates CO and its hydrogenation leads to chain growth, while the second metal acts as an oxygenation site. This research focuses on tuning the catalyst loading and the metal dispersion to ensure the two distinct active sites are in close proximity to improve the selectivity towards higher alcohols.