Cooling Tower Corrosion Inhibitors
Corrosion inhibitors are chemical compounds, organic and
inorganic, that impede electrochemical reactions which cause metals to corrode.
There are three classifications that define an inhibitor: reactive,
precipitating, and filming inhibitors.
- Reactive Inhibitors: These inhibitors react to
the metal piping by corroding a thin layer of the pipe then bonding to the
surface to create a protective or passive film that holds firm even in high
velocity, turbulent flows. They can even offer some protection from corrosion
for a period of time after treatment has been halted.
- Precipitating Inhibitors: These are inhibitors
that precipitate the inert chemical layer that lines the metal piping. Unlike
reactive inhibitors these do not bond to the metal, but are also able to handle
high velocity and turbulent water.
- Filming Inhibitors: These are organic chemicals
that form "electrostatic" bonds to metal creating a hydrophobic layer
that separates the water from the lining of the pipes. Unlike the reactive
inhibitors, filming inhibitors do not require any corrosion to form a bond with
the pipe. However, these inhibitors do not handle high velocity, turbulent
water as well as the other two categories of inhibitors.