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Exploratory Study for the Mechanism of Surfactant Restraining the Coke on the Surface of the Reactor in Residue Slurry Phase Hydrocracking

Cui, Min, Li, Chuan, Wang, Jiqian, Deng, Wenan
Energy & Fuels 2016 v.30 no.4 pp. 2941-2947
adsorption, betaine, catalysts, cetyltrimethylammonium bromide, oils, slurries, sodium, surfactants, Venezuela
The product distributions in slurry phase hydrocracking of a kind of heavy oil (AR from Venezuela, VAR) with four kinds of surfactants (cetyltrimethylammonium bromide (CTAB), sodium dodecyl benzenesulfonate (SDBS), 12 alkyl two methyl betaine (TATMB), and OP-10 (OP)) were studied to select the best surfactant restraining the coke on the surface of the reactor (cokeS). In order to understand the action mechanism of surfactant, the asphaltene surface functional groups were analyzed, and the catalyst’s average diameter, system’s colloidal stability parameter (CSP), and asphaltene’s adsorption performance on the metal surface were measured also. Results indicated that CTAB could reduce cokeS from 1.6 to 0.4 wt %, while SDBS increased cokeS, and TATMB and OP almost do not affect cokeS. Only the change regulation of asphaltene’s adsorption performance and cokeS was consistent with different surfactants, which implied the asphaltene’s adsorptivity on the metal surface should be the critical factor controlling cokeS. The study showed the asphaltene of VAR was acidic, so CTAB with the weak basic amino group could react with VAR asphaltene, thereby restraining the adsorptivity of asphaltene on the surface of the reactor, which caused the decrease of cokeS. The mechanism of surfactant decreasing cokeS was proposed that the surfactant with the opposite functional group compared with the acidity or basicity of asphaltene can react with asphaltene through acid–base action to restrain the adsorptivity of asphaltene on the surface of the reactor resulting in the reduction of cokeS.