Fluidized bed freeze concentration

Abstract

The technological industries of today could be said to thrive in the present-age industrial environment by practicing the principle of innovation. Innovation is essential for an organization to maintain a competitive edge in the industrial market. This principle is applicable within process industries which constantly require improvements in the operating efficiency of their unit operations. Concentration of liquids is an extensively applied unit operation in many industrial processes. Traditionally, liquids have been concentrated by evaporation, which exists today as an established industrial technology. However, other innovative but Iess well-known methods of concentrating liquids also exist that are currently the subject of much research. These include techniques such as freeze concentration and reverse osmosis. Freeze concentration is an alternate process to evaporation, which can be used to partially concentrate liquids. This is achieved by exploiting the concept of preferentially freezing water out of the solution at the solution freezing point. The advantage offered by freeze concentration is the retention of many volatile aromatics within the liquid due to its Iow operating temperatures. In food products, retention of volatile aromatics provides a heightened sense of flavour and other sensory attributes which can be Iost at higher temperatures of operation through evaporation. At Iow operating temperatures, the nutritional value of the concentrated food product is also preserved. Due to such advantages, freeze concentration is a popular process within the food industry. Another benefit of freeze concentration is the lower energy requirement to freeze water in comparison to its evaporation. This advantage can yield significant energy savings for all process industries employing liquid concentration in their unit operations. The full capability of this benefit has not yet been commercially realised and further investigation in this area of research continues. Currently the principle disadvantage linked to the freeze concentration process is its very high capital investment incurred from the individual costs of its processing equipment. This has significantly weakened its likelihood to be integrated in the industry as an economically competitive process. Research is ongoing to develop alternate processing techniques that can reduce the capital as well as running costs associated with freeze concentration. Our research was carried out in a similar vein in which a novel modification to the current freeze concentration process was investigated for its feasibility to freeze concentrate liquids. This modification to the process can potentially improve the economic feasibility of its operation by reducing its capital investment as well as operating expenditure.