Predicted Effects of Heavy Feeds on the Deactivation of a Commercial Atmospheric Residue Desulfurization Catalyst System

Abstract

The effect of three atmospheric residual oils on the deactivation of a commercial atmospheric residue desulfurization (ARDS) catalyst system was assessed using a commercial catalyst system consisting of five catalysts loaded inside a two-reactor pilot plant. The hydrodemetalation (HDM) and hydrodesulfurization (HDS) reactions of the three residues over the catalyst system were studied. A deactivation model considering metals and carbon deposition was used to fit the life test data. Experimental and simulated data were compared. The effect of the residual oils on each of the catalysts was evaluated, and the catalyst contribution was calculated highlighting the importance of predicting different catalyst activities during the design of a composite catalyst bed.

Deposits Effects on Catalysts Porous Structure and Chemical Activity during Residuum Catalytic Hydro-treatment

“…Also the degradation of pore structure parameters observed for CAT-1 and CAT-2 justifies the activity loss observed for both catalyst samples with ��� 0 =059 mm, which is found to be 20 and 11% respectively [14]. The analysis of the porous structure of spent CAT-1 and CAT-2 showed that the most probable diameters of pores had dropped to 45 and 51 ( Å) for dp (1) and to 75 and 82( Å) for dp (2) for both samples respectively. The micro-pores with diameters less than 20 Angstrom (Å) were seriously infected and isolated.…”

“…6. Vp (1) 0.37 89.5 0.37 95 Vp (2) 031 95.3 0.32 93 dp (1), ( Å) 57 68.7 65 74 dp (2) , ( Å) 115 93.5 122 95.3 Samples with larger particle having ��� 1 = 0.326 mm showed the results given in Table 8. The spent catalyst samples showed a higher loss in their pore structure parameters [ Tables 8,9].…”

“…It is noticed that spent catalysts after 450 hours of operation had lost the major portion of their porous structure parameters, while keeping more than 80%and 89% of their chemical activity for CAT-1 and CAT-2 respectively [14]. Vp (1) 0.41 0.18 0.39 0.23 Vp (2) 0.32 0.14 0.34 0.17 dp (1) 83 45 87 51 dp (2) The only explanation for this phenomenon is that coke deposited in the pores of the catalysts during the first stages does not impose the active centers to operate as active sites attracting reactants i.e. electrical charges can move through the deposited coke layer and hence catalyzing reactions.…”

“…(1) : Pore volume measured with N 2 Ads-Des technique, Vp (2) : Pore volume measured with mercury penetration, dp (1) : Most probable pore diameter in Angstrom( Å)measured with N 2 Ads-Des. , dp (2) : Most probable pore diameter in Angstrom(Å) measured with mercury penetration technique. ρ obs.bed observed bed density g/cm 3 .…”

“…It has been suggested that the operating catalyst behavior is drastically affected by the physicochemical properties of the treated oil feedstock and the catalyst characteristics [1,2]. The analysis of used catalysts led to that the activity loss is attributed to carbonaceous and metallic deposits altering the chemically active surface and the physical structure of the employed catalyst [3,4].…”