Sodium lignosulfonate flocculation kinetic study on Kawengan crude oil emulsion destabilization

Abstract

The flocculation process has a lot of applications such as pulp and paper, food, cosmetics, and oil industries. Despite the broad application, the mechanism itself is not well understood. The development of a mathematical model to explain the emulsion flocculation phenomenon is essential for studying and understanding the kinetics stability of the emulsion system. Sodium lignosulfonate (SLS) is a surfactant that is commonly used in the industry. This surfactant can be obtained from lignin sulfonation. SLS has long been used as a plasticizer, flocculant, and dispersant. SLS also has potential use in Enhanced Oil Recovery (EOR). This study aims to examine the flocculation kinetics of crude oil emulsion systems with SLS surfactants. With the understanding of mathematical model it can be used to determine the optimal concentration of SLS required for crude oil emulsion. The emulsion stability is studied by determining percentage of emulsion with other phases while kinetics is studied by microscope observation to count the total amount of droplet on different variables, and obtain the flocculation and coalescence constant. It is observed that the addition of SLS enhances emulsion stability but adding more than 1000 ppm reduces the emulsion volume, this is because at high concentration the emulsion instability is caused by rapid coalescence. The addition of SLS concentration of at least 500 ppm can stabilize the emulsion up to 60%. The greater the SLS concentration, the smaller the flocculation constant and coalescence constant, which indicates that the emulsion is more stable. This indicates that the crude oil emulsion system is more stable than others. The order of emulsion stability (in addition to 1000 ppm SLS) is: crude oil > hexane > heptane > iso-octane. The longer the carbon chain, the higher the emulsion stability.