Simulation of the Bench-Scale Reactor

FIGURE 9.5 Sulfur concentration profile in liquid bulk and catalyst surface at 400°C, 6.9 MPa, and LHSV = 1 h , ( ) experimental value. 

Modeling of Processes and Reactors for Upgrading of Heavy Petroleum 

On the other hand, hydrogen present in liquid is rapidly consumed and because of mass transfer it reduces its concentration. In the next section of the reactor, the easiness of hydrogen sulfide transfer and hydrogen concentration in liquid phase increase gradually from liquid to gas phase by the effect of equilibrium. Constant concentration of these compounds is expected at the last part of catalytic bed supposing equilibrium, but in the experimental reactor it does not seem to occur. 

The model was used to predict the concentrations of sulfur at 8.3 MPa, which is a different hydrogen partial pressure from that used for deriving the kinetic 

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Figure 7.17c and d show the predicted dynamic liquid molar concentration profiles of sulfur along the commercial catalytic bed at different times ranging from 60 to 1700 s for an inlet reactor temperature of 340°C. The dynamic simulation was carried out at the same reaction conditions than those employed for the simulation of the bench-scale reactor. The value of sulfur concentration reported at the exit of the isothermal bench-scale reactor is represented by symbol o . The profiles with a pronounced reduction of sulfur concentration in the first section of the reactor have already been reported by Jimenez et al. (2007). They attributed those sulfur concentration shapes in the catalytic bed to the kinetic model considered and to the operating conditions simulated. Also, the bench-scale experimental sulfur concentration value was higher than that predicted for the commercial reactor because of the increasing catalytic bed temperature observed in the liquid phase of the adiabatic reactor. 

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