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, including dairy, fruit and vegetables, meat and prepared foods.
Here are some considerations to keep in mind when selecting the right heating solution for your plant’s food or drink process.
Minimizing environmental impact, maximizing profit
In order to reduce environmental impact and make best use of byproducts and biomass wastes, many food producers have invested heavily in bioenergy production projects such as anaerobic digestion and biomass combustion, 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 re-using 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.
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 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 pizza sauce not staying on the pizza.
Another challenge is presented by certain fat-free products, which become more or less viscous with temperature, and 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 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.
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 keep things flowing smoothly while handling the product gently. For example, overcoming the pizza sauce example from 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 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, ensure that the equipment you choose will perform as required. 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.