Material balances, calculated pilot plant

Calculated Material Balances. Material balances calculated for selected elements are shown graphically in Figures 4 and 5 for the Livermore 125-kg retort and the SRC pilot plant. The mass flow balances... 

Figure 5. Calculated material balances for selected elements in the SRC pilot plant. Ft. Lewis, WA...

Material Balance. In Pilot Plant Run No. 10, during two hours of steady-state operation, all the materials in and out of the system were accounted for in order to calculate a material balance. The balance is shown in Table VI. Note that most of the values closed to within 10 percent with the exception of calcium. The discrepancy in calcium may have resulted from accumulation in the scrubber column or other parts of the system and losses in the filter washwater. 

A detailed model of the pilot-plant MVC was derived and validated against experimental data in a previous study (Barolo et al., 1998 and also see Chapter 4). The model consists of material and energy balances, vapour liquid equilibrium on trays (with Murphree tray efficiency to account for tray nonideal behaviour), liquid hydraulics based on the real tray geometry, reflux subcooling, heat losses, and control-law calculations based on volumetric flows. The model provides a very accurate representation of the real process behaviour, but is computationally expensive for direct use within an optimisation routine. Greaves et al. (2003) used this model as a substitute of the process. 

Normally reactors will be equipped with thermocouples within the catalyst bed and at the inlet and outlet. As a first step in troubleshooting, the temperature profiles should be plotted and checked for consistency with heat and material balance calculations. Likewise, pressure drop and pressure drop profiles should also be checked for consistency versus predictions for the actual conditions of the operation. Pretreatment of the catalyst such as sulfiding should be checked against normal or pilot plant procedures. 

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