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Modelling tools for heating and cooling of pumpable particulate foods

Identification

Key words Heating, cooling, heat transfer, modelling, reduction of microorganisms, heat exchanger, tube, scrape surface heat exchanger, holding tube
Latest version 2010/12/22
Completed by SP

How does it work?

Primary objective The existing models can be used for designing processes for producing liquid food products or liquid food products containing particles, such as soups and sauces, which are heated and cooled using conventional heat exchangers.
Working principle Numerical methods and mathematical models describing physical, chemical and biological processes are used to design processes for microbial reduction or conversion processes. The models are used to ensure sufficient heat treatment or to optimise heat treatment. The existing models can be used for designing processes for producing liquid food products or liquid food products containing particles, such as soups and sauces, which are heated and cooled using conventional heat exchangers. These are usually scraped surface heat exchangers, tubular heat exchangers and plate heat exchangers, usually in combination with holding tubes. To simulate these kinds of processes and to ensure sufficient microbial reduction or chemical or biological changes it is necessary to have thermal data, flow property data as well as kinetic data, such as D- and z-values for target organisms.
Images
Additional effects Also chemical changes occurring in the product during heat treatment may be calculated if necessary kinetic data is available, for example degradation of heat sensitive vitamins.
Important process parameters
Important product parameters Physical properties of foods such as thermal conductivity, thermal diffusivity, heat transfer coefficients, density, specific heat and viscosity.

What can it be used for?

Products Liquids, liquids with particles.
Operations This technology can be used in all kinds of heating/cooling processes that can be modelled. It doesn't require laminar flow.
Solutions for short comings The models can be used to optimise processes for producing liquid food products or liquid food products containing particles, such as soups and sauces, which are heated and cooled using conventional heat exchangers. The optimisation can be carried out for reduction of microorganisms and energy consumption as well as for quality aspects.

Short comings in these kinds of processes are usually over heating/cooling and thereby insufficient control of energy consumption and product quality.

What can it NOT be used for?

Products The technology of pumpable foods for sterilisation/pasteurisation is not appropriate for liquid foods with “large” particles.
Operations Not known.
Other limitations Not known.
Risks or hazards There is always a risk to obtain incorrect results using mathematical modelling because of lack of understanding of limitations of the model. Therefore it is important to validate the result, typically by use of measurement and/or consulting an expert.

Implementation

Maturity The technology is applied for available full scale equipment and pilot plant equipment. However, complexity of the models may be further developed. There are software programmes available for modelling of pasteurisation and sterilisation processes at SP and Campden BRI (e.g. PCTemp: modelling of continuously processed pumpable foods).
Modularity /Implementation The technology can be implemented in existing production, for example as a real-time application (predictive control system) where target temperatures and holding times are predicted.
Consumer aspects Science based equipment design can be displayed to consumers and users of equipment in factories to increase the trust in the technology.
Legal aspects An important application of the use of models is to guarantee (within reasonable limits) for instance the microbial reduction in food processing. It can help in verification of technology following legislative rules.
Environmental aspects None

Further Information

Institutes SP, Wageningen UR - FBR, IRTA, Campden BRI
Companies
References 1. Alhamdan, A. et al. (1998) Residence time distributions of food and simulated particles in model horizontal swept surface heat exchanger. Journal of Food Process Engineering, 21(2): 145-180.

2. Awauh, G.B. et al. (1996) Fluid-to-particle heat transfer coefficient as evaluated in an aseptic processing holding tube simulator. Journal of Food Process Engineering, 19(3): 241-267

3. Awuah, G. B. et al. (2004) Lethality contribution from the tubular heat exchanger during high temperature short-time processing of a model liquid food. Journal of Food Process Engineering, 27(4): 246-266.

4. Balasubramaniam, V.M. et al. (1996) Estimation of convective heat transfer between fluid and particle in continuous flow using a remote temperature sensor. Journal of Food Process Engineering, 19(2): 223-240.

5. Balasubramaniam, V.M. et al. (1996) Fluid to particle convective heat transfer coefficient in a horizontal scraped surface heat exchanger determined from relative velocity measurement. Journal of Food Process Engineering, 19(1), 75-95.

6. Coronel, P. et al. (2003) Pressure drop and friction factor in helical heat exchangers under nonisothermal and turbulent flow conditions. Journal of Food Process Engineering, 26(3): 285-302.

7. Friis, A. et al. (2002) Modeling heat efficiency, flow and scale-up in the corotating disc scraped surface heat exchanger. Journal of Food Process Engineering, 25(4): 285-305.

8. Koray Palazoglu, T. et al. (2002) Effect of holding tube configuration on the residence time distribution of multiple particles in helical tube flow. Journal of Food Process Engineering, 25(4): 337-350.

9. Mabit, J. R. et al. (2008) Development of a time temperature integrator for quantification of thermal treatment in scraped surface heat exchangers. Innovative Food Science & Emerging Technologies, 9(4): 516-526.

10. Norton, T. et al. (2006) Computational fluid dynamics (CFD) - an effective and efficient design and analysis tool for the food industry: a review. Trends in Food Science & Technology, 17(11): 600-620.

11. Sannervik, PJ. et al. (1996) Heat transfer in tubular heat exchangers for particulate containing liquid foods. Journal of Food Engineering, 29(1): 63-74.

12. Stranzinger, M. et al. (2002) Effect of flow incidence and secondary mass flow rate on flow structuring contribution in scraped surface heat exchangers. Journal of Food Process Engineering, 25(3): 159-187.

13. Wang, W. et al. (1999) Flow profiles of power law fluids in scraped surface heat exchanger geometry using MRI. Journal of Food Process Engineering, 22(1): 11-27.

Physical properties of foods such as thermal conductivity, thermal diffusivity, heat transfer coefficients, density, specific heat and viscosity. Software and Models 2.2.4 physical, chemical, biological stabilizing, conversion ICT ScienceDirect Keyword used: simulation, mathematical modelling, heat transfer calculations for microbial reduction in combination with “foods” and “food technology”. WikiSysop :Template:Review document :Template:Review status



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Created by WikiSysop on 29 January 2011, at 01:49