文档介绍：Chapter 7
Scale Inhibitors
Some risk of scale deposition occurs in many operations in the Inhibitors
Thermodynamic inhibitors are complexing and chelating agents, suitable
for specific scales. For example, for scale inhibition of barium sulfate, common
chemicals are ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid.
The solubility of calcium carbonate can be influenced by varying the pH or
the partial pressure of carbon dioxide (CO2). The solubility increases with
decreasing pH and increasing partial pressure of CO2, and it decreases with
temperature.
However, usually the solubility increases with higher temperature. The tem-
perature coefficent of solubility is dependent on the enthalpy of dissolution.
An exothermic enthalpy of dissolution causes a decrease in solubility with
increased temperature, and vice versa.
Kinetic Inhibitors
Kinetic inhibitors for hydrate formation may also be effective in preventing
scale deposition [1627]. This may be understood in terms of stereospecific and
nonspecific mechanisms of scale inhibition.
Adherence Inhibitors
Another mechanism of scale inhibition is based on adherence inhibitors.
Some chemicals simply suppress the adherence of crystals to the metal sur-
faces. These are surface-active agents.
Mathematical Mod