Optimization of Demulsifier Formulation for Separation of Water From Crude Oil Emulsions

Abstract

-In this study, various water-soluble and oil-soluble demulsifiers were selected for separation of water from crude oil emulsions and their productivity measured using the Bottle-test method at 70 °C and 10 ppm concentration. The best ones among 23 demulsifiers examined through the screening process were fatty alcohol ethoxylate, triethanol amine and urea from the water-soluble group and Basororol E2032, Basorol PDB 9935 and TOMAC from the oil-soluble category. Furthermore, the present study investigated the factors effective for demulsification such as temperature, concentration, pH, salinity and modifiers. It was found that the separation improves with increasing demulsifier concentration, increasing salt content, increasing temperature up to 80 °C, keeping the pH values between 5-9. Adding solvent modifiers proved unnecessary. Two formulations were prepared based on suggested optimal concentrations of demulsifier content by experimental design using Qualitec 4 and these proved to be highly effective in treating real and synthetic emulsions.

An investigation on simultaneous effects of several parameters on the demulsification efficiency of various crude oils

“…On the industrial scale, the user has to come to a compromise between admitting the higher costs of using higher concentrations of nanoparticles to save time and equipment capacity, or proceeding with lower concentrations of nanoparticles and, hence, the cost of demulsifier, even though it will result in longer separation times and, probably, larger investments on the equipment capacity. Therefore, the concentration plays a significant role in the demulsification process, so that higher concentrations increase the rate of coalescence of droplets by thinning the interfacial film …”

“…separation performance. The interfacial turbulence frequently observed during heat or mass transfer across an interface was commonly referred to the so‐called Marangoni effect and is due to the surface tension variations …”

“…Therefore, the concentration plays a significant role in the demulsification process, so that higher concentrations increase the rate of coalescence of droplets by thinning the interfacial film. [23] On the basis of these results, it should be noted that there is a limited range of nano-modified demulsifier concentration for each crude oil, based on its API degree, beyond which range no water will be removed from the emulsion. In other words, water-crude oil separation is not always improved with the enhancing impact of the nano-modified demulsifier concentration.…”

“…The interfacial turbulence frequently observed during heat or mass transfer across an interface was commonly referred to the so-called Marangoni effect and is due to the surface tension variations. [23] As for nano-modified demulsifier concentration, the demulsification temperature should be within a particular limited range, depending on the crude oil viscosity. The upper bound of the limit is set to avoid crude oil vaporization in the desalter, thus representing a safety consideration.…”

Chemical Demulsification of Model Water-in-Oil Emulsions With Low Water Content by Means of Ionic Liquids

“…Surface active agents commonly occurring in crude oils, such as asphaltenes, resins, waxes and solid particles, form rigid films at the water-oil interface, which prevent the coalescence of water droplets (de Oliveira et al, 2010;Fortuny et al, 2007;Issaka et al, 2015;Schramm, 1992;Silva et al, 2013;Sjӧblom et al, 2003;Yang et al, 2009). Numerous techniques are currently available for breaking w/o emulsions, including mechanical methods (e.g., gravity settlers or centrifugal separators), application of electric Brazilian Journal of Chemical Engineering fields (electrocoalescers), conventional heating and microwave demulsification, pH adjustment, membrane separation and chemical demulsification (Abdurahman et al, 2007;Djuve et al, 2001;Ekott and Akpabio, 2010;Guzmán-Lucero et al, 2010;Hajivand and Vaziri, 2015;Issaka et al, 2015;Yang et al, 2009). The mechanical separators and electrostatic grids commonly adopted for the destabilization of crude oil emulsions have high equipment volume and high cost for the installation on offshore platforms as main drawbacks (Ekott and Akpabio, 2010).…”