Abstract
Conventional co-current spray dryers are widely used in the dairy industry to produce milk powder. These dryers are known for their high capital costs and low thermal efficiencies and are responsible for almost 27-55% of the total energy consumption of the dairy industries. In comparison to co-current dryers, counter-current dryers have higher thermal efficiencies but they are not employed in the food industry due to the risks of product degradation.
In order to develop an alternative commercially viable and process-intensified spray-drying technology, high drying rates in a small volume must be achieved and the residence time of droplets/particles must be reduced to maintain product quality. This can be done by operating the dryer as a multizone vortex chamber unit wherein high air temperatures and high-G acceleration are employed. The objective of this thesis is to investigate the phenomena interacting in the counter-current multizone vortex spray dryer and identify the most relevant parameters for an optimal spray drying operation.
The results obtained in this study reveal that the high-G multizone drying operation with high and low-temperature zones can result in enhanced drying rates and small particle residence times. Furthermore, the in situ separation and segregation of different sized particles led to distinct drying histories and narrow residence time distributions, therefore, ensuring optimum product quality.
In order to develop an alternative commercially viable and process-intensified spray-drying technology, high drying rates in a small volume must be achieved and the residence time of droplets/particles must be reduced to maintain product quality. This can be done by operating the dryer as a multizone vortex chamber unit wherein high air temperatures and high-G acceleration are employed. The objective of this thesis is to investigate the phenomena interacting in the counter-current multizone vortex spray dryer and identify the most relevant parameters for an optimal spray drying operation.
The results obtained in this study reveal that the high-G multizone drying operation with high and low-temperature zones can result in enhanced drying rates and small particle residence times. Furthermore, the in situ separation and segregation of different sized particles led to distinct drying histories and narrow residence time distributions, therefore, ensuring optimum product quality.
| Original language | English |
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| Qualification | Doctor of Philosophy |
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| Award date | 2 Nov 2022 |
| Place of Publication | Enschede |
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| Print ISBNs | 978-90-365-5472-5 |
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| Publication status | Published - 2 Nov 2022 |