Problem Summary

Corrosion and deposition are common problems associated with once-through cooling systems.  Corrosion can be defined as the wastage or loss of base metal in a system.  Various types of corrosion can occur in once-through systems.  However, in all cases, base metal loss is encountered and corrosion products enter the bulk water stream as troublesome suspended solids.  In addition to the detrimental impact of suspended solids, serious process contamination and/or discharge problems can result from active corrosion.

Corrosion of ferrous metal piping results in the formation of iron oxide products many times the volume of the metal loss from the pipe wall.  The accumulation of corrosion products, or tuberculation, on the pipe surface reduces the carrying capacity of lines and requires expensive mechanical or chemical cleaning.  Also, the loss in head caused by tuberculation requires increased pump pressures and consequently higher pumping costs.

Deposits consist of two general types: 1) crystalline inorganic deposits (when solubility limits are exceeded) and 2) sludge (when suspended solids settle).  These deposits insulate the metal surface from the cooling water, restricting heat transfer.  Under-deposit corrosion can also occur.  If the deposit formation is severe, hydraulic restrictions to flow may further impact the cooling system's ability to carry heat away from the process.

Recommended Solution

FloGard™ Corrosion and Deposition Control Technology was developed to mitigate corrosion and fouling in mill fresh water systems.  Since most of the freshwater flow rates are quite high, these products were designed to be effective at very low feed rates.  Specific blends are available to accommodate various FDA, potable, and technical requirements.  In addition to these FloGard corrosion inhibitors and dispersants, a line of Spectrus oxidizers are available to control freshwater biological growth.  These are designed to augment or replace chlorine where safety or ease of feed is a significant concern.

Key benefits associated with FloGard™ Corrosion and Deposition Control Technology include:

Reduction of pipe loss
Reduction of equipment fouling due to upstream corrosion
Reduction of bleaching chemical demand
Improved manganese and iron removal
Lower equipment maintenance costs
Reduction in brightness reversion and bleaching chemical demand

Hercules is the global, exclusive distributor for GE Water Technologies products.  FloGard and Spectrus are GE Water Technologies trademarks and are used under license. These trademarks may be registered in one or more countries.