1th INTERNATIONAL CONFERENCE ON ADVANCES IN ENGINEERING SCIENCES: THAILAND 2017, Phuket, Thailand, 3 - 05 July 2017, pp.41-48
Achieving reliable products with thermal processes is based on the theory of microbiological destruction. Heat treatment is also a processing step to obtain the desired structure in dairy products like yoghurt alongside microbiological safety. Heat applications such as pasteurization and sterilization are considered as traditional methods.
In addition to traditional methods, new thermal technologies have been developed. These are radio frequency heating, microwave processing, infrared heating, ohmic heating and combined high pressure thermal treatment. Heat treatments today, also face competition from a number of other methods such as irradiation, ultra high pressure, pulse light techniques, high voltage methods, membran processes and other combination processes.
Since every product is heated at least once in the dairy processing, heat exchangers are the most used equipment in the dairy industry. Today, the heat exchangers used in the dairy industry are divided into batch and continuous systems. Continuous systems are divided into direct and indirect methods. Continuous systems are not feasible for every product that can be produced by the batch system.
Thermal processing is energy intensive. As a rule, short time heat application at high temeperatures is less harmful to food than long time heat application at low temperatures. Thus, the development of new heat exchangers that work with less energy and cause less damage to food has begun to gain importance. The best quality milk product is obtained by direct heat echanging. Because heat treatment in this way is minimum.
Since most of the energy consumed in the dairy industry is heat energy, opinion of saving from heat has been raised and the regeneration of the heat energy has been suggested. Because the highest regeneration is achieved with indirect heat exchangers, these equipments are the most preferred by dairy processors. Nowadays, although the term of heat exchanger includes all kinds of heat exchangers, indirect heat exchangers are understood as the heat exchenger in particular. The most commonly used indirect heat exchangers in the dairy processing are plate heat exchangers, tubular heat exhangers and scraped surface heat exchangers. We will discuss the advantageous and disadvantageous aspects of heat exchangers after we give information about them in this work.