Reaction mechanism and kinetic modeling of hydroisomerization and hydroaromatization of fluid catalytic cracking naphtha

•A mechanistic pathway was proposed for FCC naphtha hydro-upgrading.•A twenty-two lump kinetic model was presented for FCC naphtha hydro-upgrading.•An octane number prediction model was developed based on the lump model.

Hydroisomerization and hydroaromatization of fluid catalytic cracking (FCC) naphtha and model hydrocarbons were investigated over a Ni–Mo/Al2O3–HZSM-5 octane recovery catalyst, and a general mechanistic pathway was proposed. A twenty-two lump kinetic model was presented based on n-paraffin, i-paraffin, olefin, naphthalene, and aromatics (PIONA) analyses. Furthermore, an octane number prediction model based on the composition of the kinetic lumps was developed. The experimental results showed that the main reactions occurring are dimerization, cracking, isomerization and aromatization of olefins. Isomerization and aromatization are very advantageous for the olefin reduction and octane number preservation of FCC naphtha in hydro-upgrading. The reaction mechanism pathway under industrial conditions mainly includes two stages: olefin interconversion and olefin aromatization, accompanied with olefin saturation. The parameters in the kinetic model and octane prediction model were estimated from experimental data and the results showed that the model predictions were in good agreement with experimental results.

Graphical abstractHydroisomerization and hydroaromatization of fluid catalytic cracking naphtha and model hydrocarbons were investigated over a Ni–Mo/Al2O3–HZSM-5 octane recovery catalyst, and a general mechanistic pathway was proposed. A twenty-two lump kinetic model was presented based on n-paraffins, i-paraffins, olefins, naphthalenes, and aromatics analyses.Figure optionsDownload full-size imageDownload as PowerPoint slide