Plug flow reactor material balance

Material and energy balances of a plug flow reactor are summarized in Table 7-7. 

TABLE 7-7 Material and Energy Balances of a Plug Flow Reactor (PFR)... 

Plug Flow Reactor (PFR) The material balance over a differential vohime dV) is... 

For a plug flow reactor, differential volume moves along the length. The following equation may express the material balance for a plug flow reactor ... 

Plug-flow reactor. Consider now the plug-flow reactor in Figure 5.3a, in which Component i is reacting. A material balance can be carried out per unit time across the incremental volume dV in Figure 5.3a ... 

Consider the segment of tubular reactor shown in Figure 8.3. Since the fluid composition varies with longitudinal position, we must write our material balance for a reactant species over a different element of reactor (dVR). Moreover, since plug flow reactors are operated at steady state except during start-up and shut-down procedures, the relations of major interest are those in which the accumulation term is missing from equation 8.0.1. Thus... 

This section treats the material and energy balance equations for a plug flow reactor. For steady-state operation the energy balance analysis leading to equation 10.1.4 is appropriate. 

Plug flow reactor (PFR) with recycle. The recycle reactor is characterized by a non-zero value of R, that is the ratio between the mass flow rate of the recycled stream and the feeding rate Q. The material balance reads for this case as... 

In a plug flow reactor the composition of the fluid varies from point to point along a flow path consequently, the material balance for a reaction component must be made for a differential element of volume dV. Thus for reactant A, Eq. 4.1 becomes... 

Consider N plug flow reactors connected in series, and let X2,.. . , be the fractional conversion of component A leaving reactor 1, 2,.. . , A. Basing the material balance on the feed rate of A to the first reactor, we find for the /th reactor from Eq. 5.18... 

This gives the relationship between Cr and in a batch or in a plug flow reactor. To find the concentrations of the other components, simply make a material balance. An A balance gives... 

Note that the difference between this material balance and that for the ideal plug flow reactors of Chapter 5 is the inclusion of the two dispersion terms, because material enters and leaves the differential section not only by bulk flow but by dispersion as well. Entering all these terms into Eq. 17 and dividing by S AZ gives... 

The importance of dispersion and its influence on flow pattern and conversion in homogeneous reactors has already been studied in Chapter 2. The role of dispersion, both axial and radial, in packed bed reactors will now be considered. A general account of the nature of dispersion in packed beds, together with details of experimental results and their correlation, has already been given in Volume 2, Chapter 4. Those features which have a significant effect on the behaviour of packed bed reactors will now be summarised. The equation for the material balance in a reactor will then be obtained for the case where plug flow conditions are modified by the effects of axial dispersion. Following this, the effect of simultaneous axial and radial dispersion on the non-isothermal operation of a packed bed reactor will be discussed. 

The concentration leaving the CFSTR, CA1, is the inlet concentration to the plug flow reactor. The material balance on component A is... 

Develop a plug-flow-reactor design equation from the material balance. To properly size a reactor for this reaction and feedstock, a relationship between reactor volume, conversion rate of feed,... 

Now, for a plug-flow reactor, the material balance is as follows for a differential volume at steady state ... 

The Reactor Model. The material balances of sulfur Cs and vanadium Cy plug-flow reactor are derived as follows ... 

PLUG-FLOW REACTOR WITH DISTRIBUTED FEED 405 From overall material balance. 

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