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Validation of a Dynamic Model Library Regarding Mix-Phases in a Liquid Food Process Lines

Christensson, Johan (2009) MMK820
Product Development
Abstract
Before a processing unit is taken into production it is prepared with water instead of product, among other things it is sterilized this way. When this preparation phase is done, the water is pushed out with the product that is about to be processed. During this phase a mixed zone of water and product occurs. This mixed zone of water and product results in a cost for the producing company due to loss of raw material and extra production time. It is also an environmental load since all the material cannot be reprocessed and some is flushed out to the sewage disposal system. A mix-phase also occurs at the end of the production, where the reversed process takes place, that is, product is pushed out with water.
Tetra Pak needs to be able to... (More)
Before a processing unit is taken into production it is prepared with water instead of product, among other things it is sterilized this way. When this preparation phase is done, the water is pushed out with the product that is about to be processed. During this phase a mixed zone of water and product occurs. This mixed zone of water and product results in a cost for the producing company due to loss of raw material and extra production time. It is also an environmental load since all the material cannot be reprocessed and some is flushed out to the sewage disposal system. A mix-phase also occurs at the end of the production, where the reversed process takes place, that is, product is pushed out with water.
Tetra Pak needs to be able to predict the volume of the mix-phase to ensure that the performance of the equipment is satisfying and so they can give guarantees to the customer. Therefore Tetra Pak has developed a computer model for mix-phases. The model is made as a part of a dynamic model library in Dymola/Modelica1.
The aim of this study is to evaluate the model for mix-phases developed by Tetra Pak and to identify where in the process the largest contribution to the mix-phase take place. To do so field tests were carried out and then compared with simulation results.
The study shows that with low computational effort, simulation results very similar to reality can be achieved. However, in this study the simulation result has only been compared with two different test results and since reality seldom duplicates itself more tests would be desired. When evaluating the results of a simulation this has to be taken into account.
The study also showed that the two things in the process that contributes the most to the mix-phase are the product properties and the level in the balance tank. The balance tank secures that the process machine does not run dry. The level in the balance tank is one of the easiest things to control in the process. By decreasing the volume in the balance tank with around 9 liters, the mix-phase can be reduced with 59%. (Less)
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author
Christensson, Johan
supervisor
organization
course
MMK820
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Dynamic Simulation, Dynamic model, Dispersion, Mix-phase
language
English
id
1502598
date added to LUP
2009-11-09 13:28:19
date last changed
2010-02-01 14:40:04
@misc{1502598,
  abstract     = {Before a processing unit is taken into production it is prepared with water instead of product, among other things it is sterilized this way. When this preparation phase is done, the water is pushed out with the product that is about to be processed. During this phase a mixed zone of water and product occurs. This mixed zone of water and product results in a cost for the producing company due to loss of raw material and extra production time. It is also an environmental load since all the material cannot be reprocessed and some is flushed out to the sewage disposal system. A mix-phase also occurs at the end of the production, where the reversed process takes place, that is, product is pushed out with water.
Tetra Pak needs to be able to predict the volume of the mix-phase to ensure that the performance of the equipment is satisfying and so they can give guarantees to the customer. Therefore Tetra Pak has developed a computer model for mix-phases. The model is made as a part of a dynamic model library in Dymola/Modelica1.
The aim of this study is to evaluate the model for mix-phases developed by Tetra Pak and to identify where in the process the largest contribution to the mix-phase take place. To do so field tests were carried out and then compared with simulation results.
The study shows that with low computational effort, simulation results very similar to reality can be achieved. However, in this study the simulation result has only been compared with two different test results and since reality seldom duplicates itself more tests would be desired. When evaluating the results of a simulation this has to be taken into account.
The study also showed that the two things in the process that contributes the most to the mix-phase are the product properties and the level in the balance tank. The balance tank secures that the process machine does not run dry. The level in the balance tank is one of the easiest things to control in the process. By decreasing the volume in the balance tank with around 9 liters, the mix-phase can be reduced with 59%.},
  author       = {Christensson, Johan},
  keyword      = {Dynamic Simulation,Dynamic model,Dispersion,Mix-phase},
  language     = {eng},
  note         = {Student Paper},
  title        = {Validation of a Dynamic Model Library Regarding Mix-Phases in a Liquid Food Process Lines},
  year         = {2009},
}