What Does Nonvolatile Mean?
Nonvolatile is the inability of a substance to readily evaporate into gas. Nonvolatile substances are usually solids with boiling points above 212°F (100°C), and do not vaporize easily at room temperature and pressure. The nonvolatility characteristics of some compounds is undesired in some applications because they can lead to scale formation and corrosion. However, nonvolatile substances are sometimes used as additives in corrosion inhibitors.
Corrosionpedia Explains Nonvolatile
Nonvolatile impurities in steam generators and boilers are a major cause of corrosion-related failures, and inefficiencies. This arises due to the ingress of the nonvolatile contaminants contained in the feed water. This leads to the accumulation of deposits, such as salt impurities, and corrosion products in the flow-restricted areas, such as tube support plates and tube sheet. Eventually, this will cause the buildup of scale on heating tubes. The deposits result into corrosion while the scale degrades the thermal performance of the steam generator, hence reducing the output.
Some nonvolatile products have benefits that make them suitable for a wide range of applications, including corrosion and scale inhibition. Typical applications include:
- Dewatering Corrosion Preventives: Contain non-volatile corrosion inhibitors that leave a protective film on the metal when the solvent evaporates.
- Corrosion Preventive Oils: Oil-based liquids that provide non-drying and non-volatile corrosion protection liquid films at ambient temperatures and used in applications where solvent based products are unacceptable.
- Corrosion and Scale Inhibitors: Nonvolatile compounds are used corrosion inhibitors and scale dispersant in the cooling water in open circuit evaporative air conditioning plants and cooling systems operating under hand water conditions.
- Oxygen Scavengers: Contain both volatile products and non volatile salts such as cobalt chloride which increases the rate of with dissolved oxygen.