Foam Cleaning Technique for Effective Chemical Cleaning

Foam Cleaning Technique: Solvents 

Foam can be used in many applications to apply a variety of chemical products for cleaning of systems. However, the most prevalent chemicals used for effective foam cleaning techniques are acids and alkaline liquids. Though most acids and alkaline cleaning liquids can be foamed, hydrochloric and sulfuric acids are used the most. Inhibited hydrochloric acid can be foamed for use on all metals except stainless steel and aluminum. These two exceptions are, however, effectively cleaned with foamed sulfuric acid with an acid intensifier added. For removing scales that contain silicates, a properly selected acid intensifier additive in combination with hydrochloric acid is very effective.

While acids and alkaline products are the most often used for foaming applications, other chemical products that are typically not thought of as “foamable” can and are indeed used successfully in foaming applications. Amongst these materials includes alcohols, glycol ethers and some hydrocarbon solvents. Typically, these materials would be precluded from use in foams as they have high vapor pressures that can collapse generated foams. However, the advancement of surfactant technology provides us with materials that can create a variety of foam types that can support these solvent types. This is advantageous for cleaning difficult, heavy deposits of organic debris that alkalinity alone is not adequate.

Of interest is foaming applications for voiding compartments of high LEL producing constituents such as hydrocarbon vapors. When it is impractical to use vapor-phase steam induction for voiding spaces of LEL vapors, another effective method is the application of high surface area foams containing the appropriate degassing agent. Please note that not all industry degassing materials can be applied through a foam-in method due to inadequate performance characteristics of the “degassing’ product. If the correct degassing agent is selected, foaming of the absorptive chemicals both relieve high LEL levels and remove latent organic deposits within equipment at ambient temperatures without steam pressure.