Fouling can be defined as the accumulation of deposits on heat transfer surfaces that lower down the heat transfer rate across the heat exchanger due to the deposit''s low thermal conductivity. It also increases the pressure drop due to higher fluid flow resistance and reduced flow area. Crystallization fouling and particulate fouling are the two most common fouling mechanisms in water cooling systems. These two are termed as mineral fouling. Mineral fouling involves the precipitation of inverse solubility salts and the transport of particles on heat transfer surfaces. To maintain efficiency of heat exchanger, fouling of heat transfer surface is important to remove.
This study presents the effect of cleaning on heat transfer characteristics of plate and double pipe heat exchangers. The main components of cleaning advice are comprised of ball collector, ball trap, circulating pump and unit pump. The fouling was generated by artificially making CaCO3 from CaCl2 and NaHCO3 for 600 minutes. Fouling concentration varied 1000, 2000 and 3000 ppm. Respectively plate heat exchanger was cleaned by inserting a ceramic ball and double pipe heat exchanger was cleaned by inserting a sponge ball after CaCO3 fouling. Plate heat exchanger overall heat transfer coefficient recovered 95% for 1000 ppm case, 83.7% for 2000 ppm case and 74.3% for 3000 ppm case in comparison with initial state. The double pipe heat exchanger overall heat transfer coefficient recovered 97.9% for 1000 ppm case, 92.8% for 2000 ppm case and 89.9% for 3000 ppm case in comparison with initial state. It can be concluded that the cleaning of ceramic and sponge ball contribute significantly to the of performance recovery for overall heat transfer coefficient and fouling resistance after cleaning experiment.