Effect of Hydroxyl Content and Molecular Weight of Biodegradable Ethylcellulose on Demulsification of Water-in-Diluted Bitumen Emulsions

Abstract

Ethylcellulose (EC) polymers with different hydroxyl content and molecular weight were synthesized in tetrabutyl ammonium fluoride/dimethyl sulfoxide medium. Their performance for demulsification of water-in-naphtha diluted bitumen emulsions was evaluated. It was found that EC with 4.5 wt % hydroxyl (degree of hydroxyl substitution, 2.4) is the most effective in demulsification. The demulsification efficiency of EC could be linked to its interfacial activity and potency of flocculation. The potency of flocculation by EC depends on its molecular weight and hydroxyl content, which affect molecular interactions. EC with higher molecular weight was found to be more effective in the demulsification of water-in-naphtha diluted bitumen emulsions.

Demulsifying water-in-oil emulsions by ethyl cellulose demulsifiers studied using focused beam reflectance measurement

“…As for EC 10 of larger molecular weight, efficient flocculation can be achieved even at 20 1C. Notably demulsification of EC4 at higher temperature (40 1C and 60 1C) was achieved even better than the case of EC 10, which was consistent with our previous conclusion on the effect of molecular weight of EC on demulsfication efficiency (Feng et al, 2011). For a given molecular structure, low-molecular-weight polymeric demulsifiers in general possess a high interfacial activity and adsorb irreversibly at the water-oil interface, causing film rupture and coalescence of the water droplets.…”

CHAPTER 11. Particle-Stabilized Emulsions in Heavy Oil Processing

“…By controlling the cellulose/sodium hydroxide/iodoethane molar ratio in the etherification reaction, EC polymers of varying molecular weight and hydroxyl content can be synthesized. 66 EC is miscible with organic solvent and is interfacially active. The interfacial activity of EC is attributed to the amphiphilic nature of its molecular structure of hydrophilic cellulose backbone and the side chain of hydrophobic ethyl substituents.…”

“…To understand the role of molecular structure on demulsification performance, Feng et al 66 synthesized six different EC demulsifiers of different molecular weights and degrees of hydroxyl substitution (DHS). The demulsification performance of EC was shown to depend on both the hydroxyl content and molecular weight.…”

MPEG grafted quaternized carboxymethyl chitosan for demulsification of crude oil emulsions

“…Recently, Lin et al . found that ethylcellulose (EC) is an effective demulsifier which can get rid of more than 90% of water from water‐in‐bitumen emulsions at an optimal dosage, and systematically studied the demulsification mechanisms . EC was shown to demulsify water‐in‐bitumen emulsions through flocculation‐promoted coalescence of water droplets, displacement, and disruption of the interfacial films and destabilize the emulsions .…”