Wax-Crystal Modification for Fuel Oils by Self-Aggregating Partially Crystallizable Hydrocarbon Block Copolymers

Abstract

The quality of life partially depends on the ability to maintain the transportation of goods and people in an efficient and reliable fashion, even under difficult climatic conditions. A well-known problem at low temperatures is the filter blockage of diesel fuel. Fuel oils contain alkanes that precipitate at low temperature as large crystals or spherulites of wax in such a way as to form gels. Thereupon the fuel loses its ability to flow and the transportation system falters or is stopped. The lowest temperature at which the fuel will still flow is known as the pour point. As the temperature approaches that of the pour point, difficulties emerge in transporting the fuel through lines and pump. Furthermore, wax crystals can plug screens and filters at temperatures above the pour point; the so-called cold filter plugging point. To combat this behavior various additives have been developed to depress the pour point or to decrease the size and alter the shape of the wax crystals; e.g., smaller sized crystals are less likely to clog either screens or filters. This paper reports on the use of a crystalline-amorphous diblock copolymer that performs, in its selfassembled state, as an efficient nucleator for the wax in middle distillate fuels.

Control of n-alkanes crystallization by ethylene–vinyl acetate copolymers

“…This provides evidence of a strong interaction between paraffins and the polyethylene segments of EVA. The crucial role of cocrystallization has been already pointed out from structural studies of blends of paraffins and ethylene-butene random copolymers [75,76] and in a different way for ethylenepropene block copolymers [81][82][83]. As suggested in the works on random olefin copolymers [75,76], the nucleation event promoted by the presence of EVA might be the precipitation of co-crystalline particles.…”

Self-Assembling Behavior in Decane Solution of Potential Wax Crystal Nucleators Based on Poly(co-olefins)

“…1,3 The 1% system was the highest one at which the structure factor of the prototype 1.5/5 PE-PEP diblock copolymer did not show any concentration effects. 3 …”

Tailored Polymer Additives for Wax (Paraffin) Crystal Control

“…The crystalline-amorphous poly(ethylene)-poly(ethylene-propylene) (PE-PEP) diblock copolymers yield in decane platelet-like aggregates (Richter et al, 1997;Leube et al, 2000). Such a morphology is adopted as a consequence of the crystallization of the PE-blocks in thin lamellar crystallites (d≈20-50Å), whereas the PEP forms brushes on both sides of the lamellae.…”

“…Small-angle neutron scattering (SANS) technique exploiting on one side the strength of contrast matching and, on other side, the wide length scale explored, from 1nm up to 1m, is a dedicated technique to investigate and elucidate complex morphologies such as those occurring in a wax-polymer-oil system (Richter et al, 1997;Leube et al, 2000;Monkenbusch et al, 2000;Schwahn et al, 2002aSchwahn et al, , 2002bAshbaugh et al, 2002;Radulescu et al, 2003Radulescu et al, , 2004Radulescu et al, , 2006Radulescu et al, , 2008Radulescu et al, , 2011. An eloquent example is that of diblock polymers (Fig.…”