Biosurfactants are becoming increasingly popular, largely due to lower toxicity and increased biodegradability compared to chemical surfactants. Physicochemical properties are very attractive as well. Only one limited study has shown that rhamnolipid may be effective as a hydrate anti-agglomerant. This work presents a comprehensive study on the effectiveness of rhamnolipids as a hydrate anti-agglomerant. We vary the concentration of various species in the fluid mixture. We also apply various subcoolings and report results for subcoolings as high as 20 oC.
In this work we use a multiple-sample test tube rocking apparatus along with temperature bath and thermocouple data acquisition to determine crystallization characteristics—the characteristics being subcooling from crystallization and melting temperatures as well as the time required for crystallization. Visual inspection is made of the agglomeration state of the fluid mixtures at their lowest temperatures; observations show a clear distinction between what is deemed as a hydrate plug and a mixture where proper anti-agglomeration is occurring. An assessment of the stability of emulsions is also made.
Mixtures of 1/1/4 parts (by weight) water/THF/oil with varying rhamnolipid concentration are used in our work. Only 2,2,4 trimethylpentane is used as the oil phase. Results show the effectiveness of rhamnolipid as hydrate anti-agglomerant when sufficient oil is present. Observations of emulsion stability in such mixtures are made.