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Getting the right recipe for heating dairy products
Heat is fundamental to the food and drink industry. From cooking and drying to other treatments such as pasteurization, heat is widely used in all but the most basic food manufacturing and processing situations, in sectors as varied as dairy, fruit and vegetable processing, meat, prepared foods, brewing, and dietary supplements. Matt Hale, International Sales & Marketing Director at HRS Heat Exchangers, looks at some of the considerations to keep in mind to ensure you select the right heating solution for your food or drink process.
As you would expect, this demand for heating (and cooling) food and drink requires a large amount of energy. The USDA Economic Research Service* estimated that in 2002 food processing in the United States accounted for some 2.75 quadrillion Btu (806 TWh) of energy, an increase in energy use by this sector of 8% per year since 1997. While there are many energy uses in food processing, this figure includes ovens, boilers and space heating, as well as processes such as drying, sterilization and concentration.
Minimizing environmental impact, maximizing profit
In order to reduce their environmental impact and make best use of their by-products and biomass wastes, many food producers have invested heavily in bioenergy production projects such as anaerobic digestion and biomass combustion in recent years, as well as other forms of renewable energy. While this has helped to reduce the sector’s environmental footprint, maximizing process efficiency and thermal efficiencies in particular is sometimes overlooked, not only as a way of improving environmental performance, but also as a means to generate greater economic returns for the business.
Recapturing and reusing heat from other sources (such as surplus heat from cooling operations or spare boiler capacity) can be an effective way of increasing capacity or adding a new production process without the need for major new heating or energy infrastructure. Depending on the application, HRS Heat Exchangers’ equipment has been shown to recover as much as 50% of previously wasted heat, which can then be used for water, space or process heating, waste treatment or other thermal applications.
Influencing factors
While some processes and materials require specific equipment, such as ovens or retorts, for others, heat exchangers are an effective and efficient solution, and are also more likely to enable heat regeneration than other systems. The choice of heat exchanger will depend on many different factors, such as the nature of the process to be carried out (pasteurization, sterilization, dehydration, etc.); the viscosity of the food or drink being processed; and whether it contains particles or pieces, etc.
Furthermore, Newtonian and non-Newtonian fluids will behave differently under different temperature and pressure regimes, and this will affect the handling required during processing. For example, if subjected to too much pressure, certain sauces may shear, resulting in them failing to meet the end specification – such as sauce not staying on the product. Another challenge is presented by certain fat-free products which become more or less viscous with temperature, and so may be more fluid on the cooling side of the heat exchanger than the heating side.
Benefits of corrugation
Such issues can be overcome by specifying the correct type of heat exchanger for the task in hand and by careful system design. Corrugated tube heat exchangers, like the HRS MI and MR Series, are available in various configurations, so that delicate materials such as cream can be processed without damage. The corrugated design also minimizes fouling in the heat exchanger, which increases the thermal efficiency and prolongs operational periods between cleaning. In addition, corrugated tube heat exchangers have a lower pumping requirement than smooth tubular heat exchangers due to their compact nature, which results in a lower pressure drop. This helps increase operational life while reducing maintenance costs compared with other types of heat exchanger.
Reducing waste
For some materials, such as curd production in the dairy sector, increased turbulence can be beneficial. Alternatively, where low pressures are required, scraped surface heat exchangers, like the HRS Unicus Series, keep things flowing smoothly while handling the product gently: one way to overcome the example above. Using the right type of heat exchanger can also help to reduce product losses caused by materials remaining in equipment at batch changeovers or when cleaning is required. Some scraped surface heat exchangers, such as the HRS R Series, can be configured to run in reverse, effectively removing product from the heat exchanger without damaging it or affecting its quality.
When dealing with any food processing machinery, it is critical to check for compliance with the necessary legislation. However, ultimately you need to ensure that the equipment you choose will perform as required. And, as with any capital expenditure, it is important to compare not just the initial capital costs, but also the operational and maintenance costs across the life of the machinery. All heat exchangers are not alike, but these differences mean that there is undoubtedly a heat exchanger solution that fits your food processing needs.
Located in Phoenix and Atlanta, HRS Heat Exchangers operates at the forefront of thermal technology, offering innovative and effective heat transfer solutions worldwide, across a diverse range of industries. With over 35 years’ experience, we specialize in the design and manufacture of an extensive range of tubular, corrugated and scraped surface heat exchangers. All our products comply with global standards. HRS has a network of offices throughout the world: Spain, USA, Malaysia, Australia and India; with manufacturing plants in the UK, India and Spain.
For sales enquiries, please contact:
+1 (770) 726 3540
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