ABSTRACT
In many industrial applications of heat transfer equipment, the surfaces washed by the streams involved in heat transfer process are susceptible to fouling, which refers to any change at the heat transfer surface, whether by deposits of fouling substances or other means, which results in a deterioration of heat transfer intensity across that surface. As it was mentioned in previous chapter with discussion of Equation 5.1, this phenomenon can significantly deteriorate the intensity of heat transfer process and heat exchanger performance by creating additional thermal resistance of fouling layer. Even more over, the decrease of channels cross section area partly blocked by the fouling deposits can lead to significant increase of pressure drop in heat exchanger and finally to clogging of the channels. According to the analysis of different publications presented by Crittenden and Yang (2011), conservative estimation of heat exchanger fouling leads to conclusion that additional costs for fouling in industrialised countries is in the order of 0.25% of Gross Domestic Product (GDP). Fouling is also the cause of around 2.5% of the total equivalent anthropogenic emissions of carbon dioxide. In most of processing industries, fouling creates a severe operational problem that compromises energy recovery and creates additional negative impact on environment. There is loss or reduction in production, increased consumption of energy and pressure losses, flow maldistributions, cost of anti-fouling chemicals, cleaning cost, etc. Inadequate detailed knowledge of the fouling mechanisms is frequently limiting the problem solution, even though the basic principles are understood for some time. The economic and environmental importance of fouling can be classified by main four categories (1) capital expenditure, (2) energy cost and environmental impact, (3) production loss during shutdowns due to fouling and (4) maintenance cost.
