Page 333 - Elements of Chemical Reaction Engineering Ebook

394 Multiple Reactions Chap. 6

Summarizing to this point, we show in Table 6-4 the equations for species
j and reaction i that are to be combined when we have q reactions and IZ species.

TABLE 6-4. SUMMARY OF RELATIONSHIP
FOR MULTIPLE REACTIONS OCCURING A PFR
IN
I
Mole balance: 3 = rJ (6-26)
dV
Rate laws: rr, = k,,f,(c~,C,,C,)
4
Stoichiometry: rJ = 1 r,, (6-16)
i=l
The basic equations (6-17)

"
F/
Stoichiometry: FT= 2 (6-20)
J= I
Stoichiometry:
5 p To
(gas-phase) C, = CTo - - - (3-45)
FT '0
(liquid-phase) C, = F/ - (6-19)
VO
I

Example 6-6 Hydrsdealkylation of Mesitylene in a PFR

The production of m-xylene by the hydrodealkylation of mesitylene over a Houdry
5
Detrol catalyst involves the following reactions:

I m-Xylene can also undergo hydrodealkylation to form toluene:

A significant (E6-6.2)
pnomic incentive . CH4

The second reaction is undesirable, because m-xylene sells for a higher price than
toluene (65 cents/lb vs. 11.4 cents/lb).6 Thus we see that there is a significant
incentive to maximize the production of m-xylene..

Ind. Eng. Chem. Process Des. Dev., 4, 92 (1965); 5, 146 (1966).
September 1996 prices, from Chemical Marker Reporter (Schnell Publishing Co.),
252, 29 (July 7, 1997). Also see http:/-/www.chemweek.com/