Evaluation of the efficiency of silicone polyether additives as antifoams in crude oil

Abstract

It is common for crude oil from wells to be accompanied by gas and water because of the presence of natural surfactants in the oil that stabilize the associated water. This causes foaming during processing in gas/oil separators because of the constant agitation and shear forces, which reduce the efficiency of the process and require chemical control by the addition of defoaming additives, or antifoams. In this work, we evaluated the chemical and physicochemical properties of commercial antifoam products based on silicone polyethers along with their efficiency in inhibiting foaming and water/oil (W/O) phase separation. The commercial surfactants were characterized by NMR spectroscopy, size exclusion chromatography, determination of solubility in different solvents, and measurement of the surface and interfacial tensions.A method to test the formation of foam in oil was used to mimic the operating conditions in gas/oil separators. Finally, tests were performed with the addition of aliquots of the additive solutions (30% p/v) in oil to evaluate their efficiency in breaking up the foam under different conditions. The results show that the most polar additive (SL2) was the most efficient in breaking up the foam. Additive SP1, which formed a heterogeneous phase in the oil, was also an efficient foam inhibitor and helped to separate these phases. The antifoam tests showed that these additives did not stabilize W/O emulsions, so they could be used in gravitational separation tanks in the field.

Development and evaluation of oil in water nanoemulsions based on polyether silicone as demulsifier and antifoam agents for petroleum

“…Surfactants based on polyether silicone of different polarities and molar masses were selected to act on the stabilization of the o/w nanoemulsions developed in this work. Previous study showed the high efficiency of these additives in the petroleum emulsions demulsification process, this factor being the preponderant that led to the choice of these compounds. Samples were called SP1, SP2, SP3, SP4, and characterization demonstrated in Table has been executed by the company providing the additives, Momentive, São Paulo‐Brazil.…”

“…The (o/w) nanoemulsions as defoamers for petroleum efficiency evaluation was executed based on the methodology developed in lab and utilized in previous work …”

“…The demulsifiers and defoamers generally feature amphiphilic character, in other words, they possess a hydrophilic portion that interacts preferably with water molecules and another one hydrophobic, of greater interaction with the oil phase …”

“…In a previous work, the chemical and physico‐chemical properties of commercial antifoam products based on silicone polyethers were evaluated, along with their efficiency in inhibiting foaming. In this work, the formulations were prepared in organic solvent (toluene), in 30 wt/vol % concentrations.…”

“…So, in this work, oil in water (o/w) nanoemulsions, with different oil phases and stabilized by surfactants based on polyether silicone were developed and evaluated regarding their efficiency for the inhibition of foam formation, formed in petroleum and for the destabilization of emulsions in petroleum. The additives used in this work have been evaluated in previous studies in the toluene solutions and showed good efficiency in breaking oil emulsions. However, we point out that it is the first time that these surfactants are being used for the development of nanoemulsions for application in the separation of W/O emulsions.…”