Effect of Spacer Length between Phenyl Pendant and Backbone in Comb Copolymers on Flow Ability of Waxy Oil with Asphaltenes

Abstract

Waxy crude oil containing large amounts of paraffins often results in various difficulties in extraction and transportation, especially at low temperature. Comb-type copolymers with phenyl pendants were found to be able to improve the flow ability of waxy oils effectively. To investigate the influence of spacer length between phenyl pendant and polymer backbone in comb copolymers on the flow ability of waxy oil, poly­(α-octadecene-co-maleic acid phenyl alkyl amide)­s with various spacer lengths were synthesized by modification of poly­(α-octadecene-co-maleic anhydride) with aniline, phenethylamine, phentermine, and phenyl-undecanoicamide. Their effects on the morphology and crystallization of model and crude oils were observed by polarized light microscopy and DSC. The flow ability of both oils in the presence of copolymers was studied by means of rheology, including measuring yield stress, viscosity, and thixotropic properties. It is found that the spacer length remarkably affects the rheology and wax crystallization behaviors for both oils. The copolymer with a longer spacer can provide better flexibility of phenyl pendants to disperse asphaltenes more effectively, and the long spacer can cocrystallize with long-chain paraffins.

Effect of Aromatic and Aliphatic Pendants in Poly(maleic acid amide-co-vinyl acetate) on Asphaltene Precipitation in Heavy Oil

“…Maleic anhydride copolymers (MACs) are found to be capable of improving the cold flow of waxy oils in our previous work. A significant cognition is that the aliphatic chains in maleic anhydride copolymers can insert to and cocrystallize with the wax crystal layers and inhibit the growth of the wax crystal, and the aromatic or polar groups attract asphaltenes by intermolecular forces and prevent them from further deposition.…”

“…The reported dispersants include amphiphilic molecules such as dodecylbenzenesulfonic acid derivatives, 8 alkylphenols, 9,10 ionic liquid, 11−14 and macromolecules such as polyoxide, 15 polyolefin alkylamine, 16 and polyesteramide 17 as well as α-olefins and maleic anhydride derivatives. 18−22 Maleic anhydride copolymers (MACs) 18 are found to be capable of improving the cold flow of waxy oils in our previous work. A significant cognition is that the aliphatic chains in maleic anhydride copolymers can insert to and cocrystallize with the wax crystal layers and inhibit the growth of the wax crystal, and the aromatic or polar groups attract asphaltenes by intermolecular forces and prevent them from further deposition.…”

“…To solve these problems, asphaltene dispersants have been developed and widely applied worldwide . Several approaches − are available for stabilizing asphaltenes and preventing them from deposition, in which chemical dispersant is an effective one. A valid chemical dispersant generally contains an “anchoring” aromatic or polar group, which attaches itself to the surface of asphaltenes, and a “blocking” aliphatic group, which blocks asphaltenes from forming big clusters.…”

“…A valid chemical dispersant generally contains an “anchoring” aromatic or polar group, which attaches itself to the surface of asphaltenes, and a “blocking” aliphatic group, which blocks asphaltenes from forming big clusters. The reported dispersants include amphiphilic molecules such as dodecylbenzenesulfonic acid derivatives, alkylphenols, , ionic liquid, − and macromolecules such as polyoxide, polyolefin alkylamine, and polyesteramide as well as α-olefins and maleic anhydride derivatives. − …”

Effective Crude Oil Pickering Emulsification by Oil-soluble Polymer Brush through Inverse Phase Emulsion Polymerization

“…Among various viscosity reduction practices, chemical additives serve as a promising solution due to its stable performance and cost efficiency. For example, researchers have widely used amphipathic polymers, such as α-olefins-maleic anhydride copolymers [3][4][5] , ethylene-vinyl acetate copolymers [6] , and poly[N,N-(dimethylamino) ethyl methacrylate] (PDMA)-poly(lauryl methacrylate) (PLMA) copolymers [7] to stabilize crude oil in water by forming emulsions and the effect of internal and external parameters such as chain lengths, hydrophilicity/hydrophobicity balance as well as pH and ionic strength on emulsification process has been extensively investigated.…”