Research On The Effect Of Additives On The Residue Colloidal Behavior And Stability

This study selecting LGAR as raw material,using mass fraction normalized conductivity method, rheology parameter method and Zeta analytical methods, and by measuring the changes of kinematic viscosity, four component content, number average molecular weight of four component, and colloid stability parameters (CSP) of LGAR, invesitigated the effect of additives on the residue colloidal behavior and ability in both the asphaltum-residue oil system and asphaltum-toluene solution system. We draw conclusions that:(1) Four Active additives including Sodium Dodecyl Sulfate (SDS), Cetyltrimethyl Ammonium Bromide (CTAB), Oleic acid (OA) and Coconut Amine(CA)can all change residual colloidal behavior under different content in different way .Among them CA have the most obvious function,under the content 0.5% ,the kinematic viscosity of LGAR reduce to 26.5%,the mass fraction normalized conductivity and the colloid stability parameters (CSP) decreased ; Meanwhile,in the LGAR-toluene solution system, asphaltene is hydrodynamic sphericity and shows obvious salvation phenomenon, and increase the scrambling of asphaltene particles. The sequence of the abilities of active additives accelerating asphaltene salvation is CA>OA> SDS > CTAB. SDS, OA and CA can disaggregate asphaltene, and the sequence of the abilities of active additives disaggregating asphaltene is CA>OA>SDS, while CTAB can accelerate the aggregation of asphaltene.(2) Actives additives SDS, CA and OA can change the Zeta potential, quantity of electric charge, granularity and electric repulsive potential between colloidal particles. The Zeta potential, quantity of electric charge and electric repulsive potential between colloidal particles increased, and then decreased, while the granularity of colloidal particles decreased, and then increased with the concentration of SDS and CA increased, and the extremum separately present to the mass fraction of 0.7%(SDS) and 0.5%(CA). OA can make the Zeta potential, quantity of electric charge and electric repulsive potential between colloidal particles increased, and the granularity of colloidal particles decreased. The magnitude of electric repulsive potential between colloidal particles is one of the main factors to restrain the aggregation of asphaltene.(3) Eectron-supply solvents 1-methyl-2-pyrrolidone (NMP) and tetrahydrofuran (THF) can both change the kinematic viscosity,It can break the weak bonds of small molecule phases and frame cells, and make the structure of residue fractions changed and rearranged, the average relative molecular weight of asphaltene increased, the contents of S, N of asphaltene decreased and the mass fraction normalized conductivity of asphaltene-toluene solution increased. And it proves that the electric property was one factor affecting the dispersion characteristics of residue.