Inventors:
Frank Craft - Memphis TN, US
David Drummonds - Homewood AL, US
Shade Mecum - Charlotte NC, US
International Classification:
B01D061/00
US Classification:
210/651000, 210/650000, 210/652000
Abstract:
A method for the treatment of circulating cooling water to remove undesirable chemical, particulate and biological components to minimize fouling, scaling and corrosion. A saturated solution of calcium carbonate is maintained in a cross flow filtration system by controlling the concentration of precipitated salts, temperature and/or pH. The turbulent agitation of the water circulating in the cross flow filtration loop encourages the precipitation of the dissolved calcium carbonate from the saturated solution. The concentration of particulates in the cross flow filtration loop is controlled with respect to the filter membrane flux by balancing the rate of withdrawal of concentrate against the rate of addition of feed water from the circulating cooling water. Additionally, chemicals may be added to the circulating cross flow filtration loop to precipitate other dissolved chemicals. The cross flow filter may be a microfilter or a nanofilter. The permeate from the cross flow filter may be further polished with a nanofilter or reverse osmosis system. The reject from the nanofilter or the reverse osmosis system may be returned to the circulating cross flow filter loop to further enhance the kinetics of the precipitation reaction. Blowdown from the circulating cross flow filter loop (containing a slurry of precipitated chemicals) may be further concentrated with a dewatering device. The water separated from the slurry may then be returned to the circulating cross flow filter loop to enhance the precipitation kinetics.