Temperature control at the wall in ohmic heater for dairy products
- How does it work?
- What can it be used for?
- What can it not be used for?
- Related Facilities
- Further Information
|Key words||Ohmic heating, fouling, dairy product, wall effect, surface temperature, laminar flow, cooling system, coolant|
|Completed by||INRA - IATE|
How does it work?
|Primary objective||Offering a heating treatment process with reduced damage to neither the dairy product nor the device.|
|Working principle|| Introduction:
Conventional thermal treatment techniques use indirect heat exchanges that generate wall phenomena with harmful effects (fouling, strong protein denaturation, generation of neo-formed contaminants, etc.). Ohmic heating is a volumetric, continuous and direct heating technique. Yet, the laminar flow through the treatment duct generates a speed gradient: the food product heating is slower at contact with the duct side, and faster at the centre of the duct. Consequently, the product on the sides stays longer in the pipe, and with the same energy input, it leads to an excessive heating, possibly causing damages: alteration of product qualities and fouling of the duct. (1,2,3)
This new ohmic heater uses a temperature control sensor and a cooling system to have an equal temperature at every point of the flowing product. The cooling system uses a circulating fluid.
|Important process parameters||Temperature retro-control|
|Important product parameters||electrical conductivity, food composition|
What can it be used for?
|Products|| Homogeneous and heterogeneous dairy products.
Only liquid or viscous products
|Solutions for short comings||Degradation of product qualities with conventional heating processes (pasteurisation, sterilisation)|
What can it NOT be used for?
|Operations||Non thermal operations|
|Other limitations||not known|
|Risks or hazards||not known|
|Maturity|| The technology is available as pilot development equipment available for external users:
UHT pilot plant (100 L/h), R&D trials assistance, testing laboratories (Polytech Montpellier).
It is also purchasable at industrial or pilot scale.
|Modularity /Implementation||The technology requires a specific device which can be set up inside an existing line (continuous process).|
|Consumer aspects||Not known|
|Legal aspects|| A French patent has been registered FR 2 863 829 – A1 (5)
Please check local legislation.
Facilities that might be interesting for you
|Institutes||UMII - Polytech|
|Companies||GEA Niro, Emmepiemme|
|References|| (1) Bansai B. and Chen X.D. 2006. Effect of temperature and power frequency on milk fouling in an ohmic heater. Food and Bioproducts Processing, 84:4, pp. 286-291.
(2) Stancl J. and Zitny R. 2009. Milk fouling at direct ohmic heating. Journal of Food Engineering, 99:4, pp. 437-444.
(3) Ayadi M. A., Bouvier L., Chopard, F., Berthou M. and Leuliet J. C. 2003. Heat treatment improvement of dairy products via ohmic heating process: Thermal and hydrodynamic effect on fouling. In P. Watkinson, H. Muller-Steinhagen, & M. R. Malayeri (Eds.), The proceedings of the engineering conference international (ECI): Heat exchanger fouling and cleaning-fundamentals and applications
(4) Simpson D.P. and Stirling R., 1984. Apparatus for heating electrically conductive flowable media. US patent (not valid since 2001): US 4 434 357 A
(5) Beaucour P., Faydi-Bernadi E., Ponchard-Brutel A., Courel M., Gardin H., and Pain J.P., 2005. Procédé de traitement thermique continu de fluide et dispositive pour la mise en œuvre de ce procédé. French patent: FR 2863829 – A1
Temperature retro-control electrical conductivity, food composition Heaters 2.2.2 physical stabilizing other Interview with the researcher of Polytech Montpellier : Pr. Jean-Pierre Pain (email@example.com) WikiSysop :Template:Review document :Template:Review status