Fouling Control and Energy Conservation

The transfer of heat between two flowing fluids is often accompanied by fouling of the surface that separates them. These deposits represent an insulating layer that restricts the flow of heat between the fluids and therefore results in a loss of heat energy recovery. Furthermore the accumulation of these unwanted deposits can restrict the flow of fluid and hence increase the demand for transport energy. Attention therefore, has to be paid to the possibility that the energy efficiency of any process involving heat transfer, may be jeopardised by the presence of these deposits on heat exchanger surfaces. The paper outlines the mechanisms by which heat transfer surfaces become fouled and the influence of the process variables. It is usually not possible to eliminate the incidence of surface fouling so that it has to be allowed for in the design of the equipment. In addition it is likely that some control measures will have to be introduced in order to maintain heat transfer efficiency and to conserve energy. Methods of control are discussed that involve the use of chemical additives and physical technologies. A combination of chemical and physical techniques for fouling control can be very effective. The discussion in the paper is illustrated with practical data, with particular reference to cooling water