ProfessorTimothy Langrish

Project Opportunities

Title: Combined drying and crystallization in spray drying

Summary of opportunity:

This project will investigate a new combined approach to producing new engineered particles with controlled particle properties with reduced stickiness to improve the yield from processing and to improve the properties in storage and use.

Opportunity synopsis:

This combined process is a new development that is evolving due to the need to stabilize powders produced from biological extracts.  A challenging issue is combining the heat, mass and momentum transfer processes with the kinetics of the solid-phase crystallization process because the temperature and moisture content of the particles influence the rate of crystallization.This project tackles important and outstanding research issues that are central to the advancement of science in this field:

1. Modelling the kinetics of solid-phase crystallization at temperatures that are higher than ambient ones;
2. Understanding of the way in which wall deposition and re-entrainment interact with the extent of crystallization in spray-dried products;
3. Developing drying systems, being groups of dryers linked together, to achieve greater control of crystallinity than the control achievable through operating a single dryer on its own.

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Project Opportunities

Title: Competitive migration of proteins within droplets and particles during spray drying

Summary of opportunity:

The objectives of this project are to assess what types of proteins are most effective as encapsulating materials for spray-dried sticky materials such as sugars and how and why the dryers can best be operated to give the greatest encapsulation effectiveness.

Opportunity synopsis:

Proteins have recently been discovered by us and co-workers to be very effective encapsulants at very low concentrations (less than 1%) compared with existing materials, such as maltodextrins, which must be used at concentrations of up to 50% when producing spray-dried honey.Key aspects of scientific significance for this project include:

1. Developing a distributed-parameter particulate drying model to account for the formation of the non-sticky protein layer on the particle surfaces;
2. Measuring the multi-component diffusion coefficients of ternary protein-sugar-water systems;
3. Assessing how the different surface activities of various proteins affect the extent of protein surface coverage and therefore selecting the most appropriate proteins for encapsulation.

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Project Opportunities

Title: Super Sorbents from Spray Drying

Summary of opportunity:

This project will combine proteins, lactose and sodium bicarbonate to create expanded particles (sodium bicarbonate) with a high surface area per unit mass that are very amorphous and sorptive (proteins) from spray drying.

Opportunity synopsis:

These particles will have enhanced sorption capacity for many different purposes, including food and health-care products.

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Project Opportunities

Title: New robust spray dryer designs

Summary of opportunity:

This project will develop more robust designs of spray dryers that give greater flow stability and are more tolerant of process upsets than current conventional designs.

Opportunity synopsis:

Such designs would be new developments that would address the challenging issue of reducing the deposition rates of particles on dryer walls, because this problem leads to significant downtime for cleaning. This project tackles important and outstanding research issues that are central to the advancement of science in this field: (i) Modelling the transient flow patterns of gas and particles in spray dryer designs at different process scales; (ii) Using this understanding to minimize the deposition rates of particles on dryer walls and the magnitudes and frequencies of flow instabilities by changing the designs and operating conditions; and (iii) Validating the deposition performance and flow behaviour of these new designs.

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Project Opportunities

Title: Energy flow models for timber kilns and total lifecycle costs of timber drying

Summary of opportunity:

This project will build a simulation of a conventional kiln based on an existing solar kiln simulation in order to
1. Compare the economics and life-cycle impacts of conventional and solar kilns, which are significant kiln choices available to industrial users; and
2. Assess the economic impact of operating kilns in different ways (e.g. continuous heating or intermittent heating).

Opportunity synopsis:

The prediction of stresses and strains in the timber, and how they develop as drying proceeds, is part of the existing solar kiln simulation and should be retained in any conventional kiln simulation, because these stresses and strains are important indications of timber quality.
Such a simulation of a kiln fits into the broader picture of developing a “virtual model” of a timber processing site or sawmill, which is necessary to assess the economic, social (including employment) and environmental impacts of the whole site.  Hence this project addresses technology support for decision support planning in economic, social and environmental terms.

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Project Opportunities

Title: Developing new multifunction layered particles with novel modular food processing systems

Summary of opportunity:

This project will develop new multifunction layered particles with novel processing systems to enable multiple bioactive dosages or functions to be delivered in one functional food product. Antioxidant extracts are produced from a variety of bio-waste sources such as Hibiscus flowers (also known as sorrel and roselle), more specifically Hibiscus sabdariffa L.

Opportunity synopsis:

This project will develop ways to combine the delivery of different extracts as separate layers on particles rather than mixed together, so that the extracts can be absorbed in the body at different stages of digestion.  This new process will use sequential drying operations that are more amenable to large-scale operation than the tableting delivery systems used in pharmaceutical processing.

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Project Opportunities

Title: Improving the scale-up of spray drying for bioactive extracts and fibres

Summary of opportunity:

This project will improve the ability to scale up the spray drying of bioactive extracts and fibres.

Opportunity synopsis:

The project will do this by exploring the effect of operating conditions on the yield from spray drying (quantity) and the antioxidant capacity of the spray-dried bioactive powders (quality).  The aim of this project is to use recent advances in understanding the flow patterns, thermodynamic behaviour, powder stickiness and crystallization-in-drying behaviour inside spray dryers, developed at the University of Sydney and elsewhere, to better operate the equipment.  We will scale up the spray drying of bioactive extracts and fibres from small scale to pilot scale and assess how to overcome the limitations.  These materials are currently very difficult to spray dry in any way, but our expertise in crystallization-in-drying offers the real prospect of large-scale production by this method.

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Project Opportunities

Title: The Effects of Spraying Materials into Gases Other than Air as a Way to Control Surface Coating by Proteins

Summary of opportunity:

In this project, an inert gas loop will be used to change the drying atmosphere from air to other gases, such as carbon dioxide and nitrogen, as a way to use these gases to control the extent of surface coating of spray-dried particles by proteins.

Opportunity synopsis:

In this project, an inert gas loop will be used to change the drying atmosphere from air to other gases, such as carbon dioxide and nitrogen, as a way to use these gases to control the extent of surface coating of spray-dried particles by proteins.

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Project Opportunities

Title: Creating and Testing Naturally-based Preservatives for Breads from Australian Herbs

Summary of opportunity:

In this project, better and more natural preservatives for bread will be made using proteins as coatings for herbal powders. 

Opportunity synopsis:

We will make dough, record how it rises, take pictures at different times during the rising of the dough.  Then we will make and add new naturally-based preservatives for breads, made from Australian herbs, and check that the bread still rises well.  The herbal preservatives will be coated with proteins so that the yeast is protected from the herbs during dough proofing, but the coating will melt on baking to release the herbs, providing protection to the bread against moulds.  Vitamin C will be used as a cross-linking agent to make the proteins less soluble during bread proofing.

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Project Opportunities

Title: Improving flow stability in small-scale spray dryers

Summary of opportunity:

The aim of this project is to improve the degree of flow stability in small-scale spray dryers. 

Opportunity synopsis:

Our work in assessing and controlling flow instabilities in large-scale dryers used in the dairy industry have shown that reducing these instabilities improves process yields due to lower deposition of particles on walls.  However, small-scale spray dryers are used in pharmaceutical industries, and these smaller-scale dryers have laminar or transitional flows rather than the turbulent flows in larger-scale dryers.  The two scales of dryer therefore have fundamentally different flow regimes, and the main scientific questions concern how, to what extent and why these different flow regimes affect the mechanisms, magnitudes and control measures in small-scale and large-scale dryers.  Specifically, these main scientific questions include:  (i) Assessing to what extent the magnitude and types of flow instabilities are different in small-scale and large-scale spray dryers; (ii) Determining how and why the mechanisms of the flow instabilities differ in the two dryer scales; and (iii) Identifying how the methods for reducing flow instabilities, such as changing the inlet levels of swirl and turbulence, might be implemented differently in the two scales of dryers.

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Project Opportunities

Title: Improving the Storage Stability of Dairy Powders by Crystallizing Spray-Dried Powders in Fluidized Beds

Summary of opportunity:

In this project, the storage stability of dairy powders will be improved by crystallizing spray-dried powders in fluidized beds.  

Opportunity synopsis:

The spray-dried forms of these dairy powders are normally amorphous (random) in molecular structure, but these amorphous structures transform into crystalline ones slowly over time in storage.  In storage, the lack of control over the transformation process and the lack of agitation during this amorphous to crystalline transformation causes problems with caking, poor flowability and degradation.  To overcome these problems with poor control and lack of agitation during this transformation, the transformation will be carried out under control in a stirred fluidized bed where the transformation can be done relatively rapidly compared with the rate in storage.  This controlled process will give more stable powder products.

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Project Opportunities

Title: Differential Crystallization of Materials During Drying

Summary of opportunity:

This project will study how different components of liquid mixtures can be separated during their combined crystallization and drying processes.

Opportunity synopsis:

The differences in sorption and solubility of amorphous and crystalline components will be used to separate various components of the mixtures, enabling natural mixtures to be separated on the basis of their crystallinity.

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Project Opportunities

Title: Wastes to Products: Towards New High-Value Products from Extraction and Spray Drying of Citrus Peels

Summary of opportunity:

In this project, wastes will be turned into valuable and useful products. 

Opportunity synopsis:

We will extract and spray dry pectin extract from orange peels in a two step extraction and direct drying process, rather than the current lengthier three-step extraction, crystallization and crystal drying process.  Spray drying involves taking liquid extracts and spraying them into hot air to form dry powders.

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Project Opportunities

Title: The Effects of Changing the Inlet Gas Temperature and Drying Atmosphere in Spray Drying on Particle Properties

Summary of opportunity:

In this project, the effects of changing the inlet gas temperature and drying atmosphere in spray drying on particle properties, such as the degree of crystallinity, the bulk density, powder flowability, and crystal shape and structure, will be explored. 

Opportunity synopsis:

In addition, an inert gas loop will be used to change the drying atmosphere from air to other gases, such as carbon dioxide and nitrogen, as a way to use these gases to control the particle properties.

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Project Opportunities

Title: Vitamin C as a Means of Controlling Crystallinity in Dairy Products

Summary of opportunity:

In this project, the minimum amount (fraction) of vitamin C that needs to be added to dairy products, such as lactose, in order to create crystalline products will be assessed.  

Opportunity synopsis:

We know that spray-dried lactose is mainly amorphous, while spray-dried vitamin C is mainly crystalline.  Given that vitamin C may be acceptable more widely as a food additive than many other compounds and that crystalline products are more stable than amorphous ones, the outcomes from this project have potential outcomes for creating more stable dairy products as powders if the minimum amount of vitamin C that creates a crystalline product can be found.

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Project Opportunities

Title: Energy Recovery in Spray Drying

Summary of opportunity:

In this project, the tradeoff between quality and energy recovery in spray drying will be explored in order to assess the energy efficiency of spray drying and the effect of different operating conditions on the product quality and the energy use.  

Opportunity synopsis:

The condensing temperatures in a recirculation system and the inlet gas temperatures for the dryer can be adjusted to affect the product humidity and the energy use.  The outcomes of this project will improve the understanding of the three-way life cycle consideration of product quality, operating energy use and embodied energy, enhancing the ability to do greenhouse gas accounting.

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Project Opportunities

Title: Comparing the Alignment of Capital Costs and Embodied Energy for Better Greenhouse Gas Accounting

Summary of opportunity:

In this project, the alignment between capital costs and embodied energy will be explored in order to assess the extent to which the assessment of energy in this way is multi-dimensional.  

Opportunity synopsis:

If the alignment between these financial costs and the embodied energy levels can be demonstrated, then the dimensionality of the problem will be reduced and the ability to do greenhouse gas accounting will be improved.