Experimental Heat Transfer, Vol.20, No.4, 323-335, 2007
Electro-flocculation mechanism of physical water treatment for the mitigation of mineral fouling in heat exchangers
The objective of the present study was to investigate the mechanism of a physical water treatment (PWT) technology used to mitigate mineral fouling in a heat exchanger. The PWT method tested utilized a solenoid coil to produce induced electric fields in a feed pipe prior to the heat exchanger. Fouling experiments were conducted using well water circulated through a laboratory cooling tower over 270 h with no blowdown, and fouling resistances were determined over time. Compared with the fouling resistance for the baseline case, those obtained with the PWT technology showed high efficacy for maintaining a low fouling resistance value. Samples of circulating well water were collected and analyzed using a laser particle counter over time. After 4 days of operation, the total number of particles was approximately 1 million per cc for the untreated case, whereas the case with PWT produced 3.5 million per cc. The present data on the particle counting provide empirical support for the bulk-precipitation hypothesis for the mechanism of PWT generally and electro-flocculation mechanism for solenoid coil techniques in particular.