Sensitivity of reactors

I Stability and Sensitivity of Reactors Accomplishing Exothermic Reactions... 

Figure 4-2 Sensitivity of reactor temperature to changes in the wall temperature for nonisothermal plug-flow tubular reactors with exothermic chemical reaction. The reactive fluid enters at 340 K.

Since Luyben identified the snowball effect (Luyben, 1994), the sensitivity of reactor-separator-recycle processes to external disturbances has been the subject of several studies (e.g., Wu and Yn, 1996 Skogestad, 2002). Recent work by Bildea and co-workers (Bildea et al., 2000 and Kiss et aL, 2002) has shown that a critical reaction rate can be defined for each reactor-separator-recycle process using the Damkohler number. Da (dimensionless rate of reaction, proportional to the reaction rate constant and the reactor hold-up). When the Damkohler number is below a critical value, Bildea et al. show that the conventional unit-by-unit approach in Figure 20.15 leads to the loss of control. Furthermore, they show that controllability problems associated with exothermic CSTRs and PFRs are resolved often by controlling the total flow rate of the reactor feed stream. 

H.S. Palme, Radiation Embrittlement Sensitivity of Reactor Pressure Vessel Steels, BAW-10056 Topical Report, Babcock and Wilcox, Lynchburg, VA, March 1973. 

Fig. 2. Scaled disturbance sensitivity of reactor-separator system. Effect of changes in reaction rate constant on distillate composition A magnitude larger than 1 at a particular frequency...

Fig. 8. Scaled disturbance sensitivity of reactor-separator process before (dashed) and after (solid) addition of delay tank and mixed buffer. See also Figure 7.

Fig. 5. Sensitivity of reactor exit composition on production rate for different reactant...

The term A/(PPw)ATad/Tsv is the well-known dimensionless number Nad used in the analysis of the parametric sensitivity of reactors (Section 4.10.3) ... 

Sensitivity of Reactor Power Level to Minimum Assembly ... 

The sensitivity of reactor outlet temperature to overall plant performance was examined for a temperature range of 1100K to 1200K. Turbine isentropic efficiency is assumed to be constant over the range of temperatures evaluated. The results of the reactor outlet temperature sensitivity study are shown in Figure 6-7. 

The HRS mass flow rate would be controlled by changing HRS pump speed. Changes in the HRS mass flow rate influence the CIT and radiator coolant temperatures. Figure 8-4 demonstrates the sensitivity of reactor power, electrical power, reactor outlet temperature, and compressor inlet temperature to changes in HRS flow rate. 

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