Effect of resin-asphaltene substances on the stability of inverted emulsions

Abstract

The effect of low-paraffin high-resin oil (HRO) and paraffin resin oil (RO) additives on the stability of emulsions obtained by mixing of solution of oil paraffin in kerosene with water is studied. Invert emulsions containing 10–40 wt. % of distilled water are prepared for 15 minutes at room temperature using an overhead stirrer at a blade rotation speed of 3000 rpm. The HRO or RO are introduced into a 6 wt. % solution of oil paraffin in kerosene (OP-k) used as an organic dispersion medium. The oils used differ significantly in their component composition. The HRO sample contains 31 wt. % of resins and practically 10 wt. % of asphaltenes. The content of resins in a RO sample is 1.5 times lower, while asphaltenes are present in trace amounts. According to the data of IR spectroscopy, the content of aromatic and condensed aromatic and naphthenic structures, C=O groups and sulfoxides in HRO is significantly higher but that of aliphatic fragments is lower. It is shown that the stability of emulsions depends on the content of water and organic phase composition. Mixtures composed of 10 wt. % water and 90 wt. % of organic phase containing up to 0.5 wt. % of HRO are deemulsified immediately after mixing is stopped. Emulsions, which are stable within 60 min, are formed if a concentration of HRO in the organic phase is 10 wt. % (3.3 wt. % of resins and 1.1 wt. % of asphaltenes) or higher. An increase in the fraction of the introduced HRO results in an increase in the stability of emulsions with a higher water content. For example, an emulsion containing 40 wt. % of water and 20 wt. % of oil (13.46 wt. % of resins and 1.98 wt. % of asphaltenes) is stable within 60 min. Emulsions, whose organic phase is doped with RO containing trace amounts of asphaltenes and lower amounts of resins than HRO, are not stable. In addition, the RO sample is characterized by a lower content of aromatic structures and heteroatomic functional groups.