Explanation of Flow Calibration Results

The catalyst bed that was charged to the reactor is now a restriction, calibrated for flow vs. pressure drop. The pressure drop equals the pressure generated by the blower, which in turn depends on the RPM. In essence, the differential pressure measurement was eliminated by calibrating the flow directly with RPM. 

The flow that is shown in these figures is the instrument flow measured as m/s in the measuring tube. Multiplied with the flow cross-section of 5.59 cm, this gives the volumetric flow in the 2.67-cm diameter flow tube. Using a different catalyst basket or measuring tube will change this ratio. The volumetric flow is the same in the basket. Because the small basket has a 3.15 cm diameter and 7.79 cm cross-section, the linear velocity will be 5.59/7.79 = 0.72 fraction of that in the tube. 

The blower is calibrated at the factory for pressure generated vs. RPM. This can be checked with a U-tube or slanted tube for measuring the 

If similar measurements are made on the catalyst to be studied, then there is a good knowledge of the flow. Operating conditions should be calculated with the measured values and evaluated at the temperature and pressure of the experiment. If, in the calculated operating conditions, some important gradients are indicated, then a corrective action should be taken. These may include  

If a catalyst is coking up or falling apart in a short time in the recycle reactor then idow will decrease and becomes unknown after a time. In this case is best to improve the life time or the mechanical properties of the catalyst before making tests in the recycle reactor. 

---