Parallel fouling model

A trickle-bed reactor was used to study catalyst deactivation during hydrotreatment of a mixture of 30 wt% SRC and process solvent. The catalyst was Shell 324, NiMo/Al having monodispersed, medium pore diameters. The catalyst zones of the reactors were separated into five sections, and analyzed for pore sizes and coke content. A parallel fouling model is developed to represent the experimental observations. Both model predictions and experimental results consistently show that 1) the coking reactions are parallel to the main reactions, 2) hydrogenation and hydrodenitrogenation activities can be related to catalyst coke content with both time and space, and 3) the coke severely reduces the pore size and restricts the catalyst efficiency. The model is significant because it incorporates a variable diffusi-vity as a function of coke deposition, both time and space profiles for coke are predicted within pellet and reactor, activity is related to coke content, and the model is supported by experimental data. 

A parallel fouling model has been developed to represent experimental observations for hydrotreating a coal oil in a trickle-bed reactor over a commercial NiMo/Al catalyst. This model accurately predicts coke profiles with time and reactor position, and hydrogenation and hydrodenitrogenation as functions of coke content. The following conclusions can be drawn from this study. 

A model based on parallel fouling was developed to represent these experimental observations. The following assumptions were made ... 

Figure 1. Fouling by wedge layering parallel bundle pore structure model...

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