 |
 |
 |
 |
 |
A hydrodynamics and reaction study of fluidized beds with a fractal injectorsupervisor: prof.dr.ir. M.-O. Coppens |
|
Background, relevance, problem definition
Fluidized bed reactors are important reactors in the chemical industry because they offer excellent possibilities when dealing with processes involving solids and fluids. By nature, gas-solid fluidized beds have good particle mixing, good heat and mass transfer and low pressure drop. However, design and scale-up of this type of reactor are quite difficult, due to the complexity of the chaotic hydrodynamics. One approach to face this problem is to try to circumvent the hydrodynamic complexity by creating a system that is more uniform and easier to control and scale-up.
Particle mixing and gas-solid contact are directly affected by size, frequency, and distribution of bubbles in bubbling fluidized beds. A bed of uniformly distributed fine bubbles will generally lead to higher reactor performance for transport limited processes, as a result of good mixing and contact. The idea of a fractal injector originates from nature, which frequently uses tree-like fractal networks to distribute components, information or energy from one or a few points to a much larger area or volume, typically in a very uniform way. By definition self-similar fractal networks are scalable, so that this system can be operated in similar ways at different scales.
Goal
The work is aimed at a better understanding of the hydrodynamics of bubbling fluidized beds with a fractal injector. The effects of a fractal injector will also be examined by applying mass transfer limited reactions.
Approach
This research project consists of three parts. The first part is the investigation of the bubble hydrodynamics of a fluidized bed with a fractal injector by means of image analysis. The second part focuses on measuring the residence time distribution of the gas in the fluidized bed. Through these studies on the bubble hydrodynamics and the residence time distribution, configurations of fractal injectors will be studied by comparing the effect of fractal structures with different numbers of outlets. The third part aims to determine if the use of a fractal injector improves the rate in mass transfer limited process, e.g., CO oxidation.
Physical Chemistry and Molecular Thermodynamics
Julianalaan 136, 2628 BL Delft, The Netherlands, Phone: +31 15 2784748, Fax: +31 15 2788047,
Last update: 12 July, 2006 webmaster