Effect of thermal-hydraulic parameters on calcium carbonate scaling in heat exchangers
[Thesis]
M. S. Khan
King Fahd University of Petroleum and Minerals (Saudi Arabia)
1996
163
M.S.
King Fahd University of Petroleum and Minerals (Saudi Arabia)
1996
The term fouling is generally used to describe the deposition of unwanted (initially fluid) particles, which increases both resistance to heat transfer and pressure drop through the heat exchanger. CaCO3 which is predominantly present in the cooling water, has inverse solubility characteristics i.e., it is less soluble in warm water, resulting in deposition of scales on heat transfer surfaces. An experimental study is carried out to determine the effect of tube surface temperature, Reynolds number, tube diameter and scaling salt concentration on the induction time of CaCO3 scaling. It was observed that tube surface temperature, Reynolds number and tube diameter have no effect on the onset time of the scaling whereas salt concentration and tube surface roughness have a profound influence on the induction period. The effect of tube surface temperature, Reynolds number, tube diameter and salt concentration on the growth rate of fouling has also been studied. It was concluded that for the range of parameters studied Reynolds number does not influence the fouling resistance substantially. However, the tube surface temperature, tube diameter and salt concentration have profound effect on the growth rate of scaling. The data collected from the experiments are used to develop dimensionless fouling resistance models for estimation and prediction purpose.