Effect of the nano-hybrid pour point depressants on the cold flow properties of diesel fuel

Abstract The nano-hybrid pour point depressants (PPDs) was prepared by organically modified nano-clay covering in polymeric PPDs, namely, polymethyl acrylate (PMA), ethylene vinyl acetate copolymer and poly-α-olefin. The effects of nano-hybrid PPDs on the cold flow properties of diesel fuel were evaluated. The crystal morphology and crystallization behavior of the diesel fuels in low-temperature were also observed by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The results indicated that the nano-hybrid PPDs always exhibited a better cold filter plugging point, while it had little effect on solidifying point compared to pure PPDs, and PMA hybrid with organically modified nano-clay in mass ratio of 4:1 exerted the best depression effect. Up addition of 0.15 wt.% nano-hybrid PMA (4:1) in diesel, the cold filter plugging point and solidifying point were reduced by 16 °C and 14 °C, respectively. DSC and POM results showed that the nano-hybrid PMA involved heterogeneous nucleation activity. The nano-hybrid PMA modified the crystallization behavior of diesel by transforming the shape of wax crystals and inhibiting the formation of larger crystals, which result in compact, regular, tiny particle-shaped and uniform arrangement wax morphologies.