Role of Pt–Pd/γ-Al2O3 on the HDS of 4,6-DMBT: Kinetic modeling & contribution analysis

Abstract

The purpose of this study is to provide insights on the function of noble metals, namely Pt-Pd catalytic system, on the hydrodesulfurization (HDS) of alkyl-substituted dibenzothiophenes (a-DBTs) by means of kinetic modeling and contribution analyses. A series of Pt-Pd systems (1% wt. nominal loading) supported on γ-Al 2 O 3 (0-100, 20-80, 50-50, 80-20 and 100-0; %mol Pt-%mol Pd) are synthesized and evaluated during the HDS of 4,6dimethyldibenzothiophene (4,6-DMDBT) at operating conditions relevant for industry: 320°C, 500 ppm of S and an H 2 pressure of 5.5 MPa. A summary of their characterization is presented as reference herein. Kinetic model based on a Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism and contribution analysis based on predicted reaction rates give rise to the following findings: the bimetallic catalyst 8Pt-2Pd/γ-Al 2 O 3 (80-20; %mol Pt-%mol Pd) leads to the highest activity; in all Pt-Pd/γ-Al 2 O 3 systems, Pt favors desulfurization reactions, i.e., 4,6-DMDBT to 3,3′-dimethylphenyl (3,3′-DMBP) and 4,6-dimethyltetrahydrodibenzothiophene (4,6-DM-th-DBT) to MCHT, whereas Pd favors hydrogenation of 4,6-DMDBT to 4,6-DM-th-DBT; and 4,6-DMDBT and methylcyclohexyltoluene (MCHT) are the hydrocarbons with the lowest and highest affinity to be adsorbed on the active sites from the studied Pt-Pd/γ-Al 2 O 3 systems, respectively.

Kinetic assessment of the simultaneous hydrodesulfurization of dibenzothiophene and the hydrogenation of diverse polyaromatic structures

“…Kinetic parameters were estimated by minimizing the objective function RSS(φ), which includes the residual sum of squares of the concentration of the different species: [57][58][59]…”

Kinetic assessment of the simultaneous hydrodesulfurization of dibenzothiophene and the hydrogenation of diverse polyaromatic structures

“…Kinetic parameters were estimated by minimizing the objective function RSS(φ), which includes the residual sum of squares of the concentration of the different species: [57][58][59] RSS…”

Estudo do desempenho de reator de leito gotejante aplicado ao processo de hidrodessulfurização do petróleo

“…Os reatores de leito gotejante se caracterizam pelo fluxo das correntes de gás e líquido ocorrerem de modo descendente através de um leito catalítico [9]. Na literatura, encontram-se revisões que abordam a hidrodessulfurização (HDS) de compostos modelos [10], frações de petróleo [11] e petróleo pesado [12] com interesse nas características mais importantes daquele processo, que são a cinética e a modelagem do reator. Diferentes abordagens cinéticas têm sido utilizadas sendo a mais comum o modelo cinético agrupado, que tentar modelar a HDS de petróleo e estabelecer a dependência dessa reação com as variáveis de processo [13,14,15].…”