Mole Balances on CSTRs. PFRs. PBRs. and Batch Reactors

7 Mole Balances on CSTRs, PFRs, PBRs, and Batch Reactors 

For liquid-phase reactions in which there is no volume change, concentrack is the preferred variable. The mole balances for the generic reaction 

The mole balances for gas-phase reactions are given in Table 4-6 in terms o number moles (batch) or molar flow rates for the generic rate law for ihi 

Must write a mole babnce on each species 

To relate concentrations to molar flow rates, recall Equation (3-42), with y = P/P  

For liquid-phase reactions, the density remains constant and consequently there is no change in either the volume V or the volumetric flow rate v = Vq during the course of the reaction. Therefore concentration is the preferred design variable. The mole balances derived in Chapter 1 (Table S-1) are now applied to each species for the generic reaction 

The mole balances are then coupled to one another using the relative rates of reaction 

Isothermal Reactor Design Molar Flow Rates Chapter 6 

The mole balances for gas-phase reactions are given in Table 6-2 in terms of the number of moles (batch) or molar flow races for the generic rate law for the generic reaction, Equation (2-1). The molar flow rates for each species Fj are obtained from a mole balance on each species, as given in Table 6-2. For example, for a plug-flow reactor 

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In ihe three idealized types of reactors just discussed (the perfectly mixed batch reactor, the plug-fiow tubular reactor (PFR). and the perfectly mixed con-tinuous-siirred tank reactor (CSTR), the design equations (i.e.. mole balances) were dei doped based on reactor volume. The deris ation of the design equation for a packed-bed catalytic reactor (PBR) will be carried out in a manner analogous to the development of the tubular design equation. To accomplish this derivation. we simply replace the volume coordinate in Equation (MO) with (he catalyst weight coordinate H (Figure - 4). 

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