Solid steam feed rate, increased

Figure 8. Solids temperature at 0.3 m, steam feed rate increased 5.0 %...

Figure 16.4 shows the Aspen Dynamics flowsheet with controllers installed. A steam-to-feed ratio is used with the ratio changed by the temperature controller. The need for this ratio to improve load performance is illustrated in Figure 16.5. A 50% increase in feed flow rate is the disturbance. The solid lines show responses without the QR/F ratio. There are very large drops in Stage 55 temperature that result in large transient increases in the C4 impurity in the bottoms (xB). The units of the multiplier must be metric in the Aspen Dynamics simulation (GJ/kmol).

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