How much free liquid hydrocarbon does it take to cause an amine solution to foam?
Answer – This is a trick question. One of the most common misconceptions (urban legends) handed down through almost 100 years of sweetening hydrocarbon gases and liquids with amine solutions is that free liquid hydrocarbon actually causes amine foaming. That’s right, liquid hydrocarbon does NOT cause amine foaming. In fact, settleable liquid hydrocarbon acts like antifoam (see Hydrocarbon Effects on Foaming). Most antifoams used in this industry are either mixtures of silica solids and silicone based oils, or large molecular weight alcohols (oils) which are also insoluble in amine (see Antifoam). If the contaminating liquid hydrocarbon has an amine soluble fraction that can act as a detergent (surfactant), it may cause solution foaming (see Foaming Abatement 02, Myth Busting 06). There is also significant evidence that suggests these soluble hydrocarbon fractions inhibit gas to liquid mass transfer which would directly affect the amine’s ability to remove acid gas (see The Effect of Hy
