Details of Grant 

EPSRC Reference:	EP/C546849/1
Title:	High-performance particle separation by vibrated liquid fluidised beds
Principal Investigator:	Biggs, Professor MJ
Other Investigators:	Ooi, Professor JY Glass, Dr D
Researcher Co-Investigators:
Project Partners:
Department:	Sch of Engineering
Organisation:	University of Edinburgh
Scheme:	Standard Research (Pre-FEC)
Starts:	01 September 2005	Ends:	31 August 2008	Value (£):	419,674
EPSRC Research Topic Classifications:	Design of Process systems Particle Technology
EPSRC Industrial Sector Classifications:	Manufacturing
Related Grants:	EP/C546857/1
Panel History:
Summary on Grant Application Form
The separation of particles on the basis of their differences in size, density and other properties is called 'classification'. The need for particle classification is wide and varied - just a few examples include the separation of diseased from healthy cells, the production of metals from their mined ore, and the separation of plastics for recycling.There are a large range of particle classification methods available that each have their own particular purpose and history. Many of these methods break down when the particles that need classification are in a dense slurry and do not work reliably and efficiently when the particles are similar in size and density or where particles stick together. We propose a new classification system based on a vibrated liquid fluidised bed that should be ideal for such systems.A liquid fluidised bed works by passing a fluid up through a packing of particles in a container so that they move about freely under the influence of gravity and drag, which act to pull down and hold up the particles respectively. Other forces that work on the particles are due to collisions between particles, and the fluid flow local to each particle. A vibrated fluidised bed works by shaking the container of particles up and down (or side to side) so that the particles oscillate under the influence of the acceleration arising directly from the shaking, gravity and collisions between particles. The mechanisms by which unlike particles separate in these two types of fluidised bed are very different. By combining both liquid flow and vibrations together, we believe these mechanisms may be made to work with or against each other to gain greater control over the separation of unlike particles.The project is concerned with determining how the system performs when the operating conditions that ultimately control the process are varied. These include the shaking (how hard and how quickly), the speed of the fluidising flow through the system and also the types of particles (their different sizes and densities) in the apparatus. The work is divided into three main parts:1. Try it out in experiments in the laboratory. Here a known mixture of particles in a fluid is subjected to a flow while the apparatus is shaken. The particle are especially chosen in such a way that by traditional methods they are difficult to classify. They differ little in size and density and we will determine the degree of separation in a vibrated liquid fluidised bed for different liquid flow rates, vibrational frequencies and amplitudes2. We have at our disposal an experimental method to determine exactly what excursions an individual particle carries out while it is in the apparatus. This information will be useful in determining what mechanism is important for the separation of particles.3. Making a theory of the classification process so that we not only understand exactly how it works, but also so that we can predict how systems that we have not yet tested will work. We will do this in two ways: (a) modelling the particle excursions as best as we can in the computer and (b) using known laws of mechanics to describe the internal workings of the apparatus by means of mathematics. Method (a) is very detailed and method (b) is more efficient, as it used averages of the the particel and fluid motion (in the same way the weather person on the television symbolises the wind by an average arrow, yet we all know that the details of the air motion may be highly complicted). Naturally, the two ways of making a theory should give the same answers. So, we can check whether we understand the mechanisms, but we can also check against the experiments in the laboratory
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