REACTORS - Teach Yourself the Basics of Aspen Plus - page 119

the molar extent of reaction X is defined by

n a
a

n b
b

n c
c

n d
d

X =− =− = = (10.2)

where n i are the moles of component i either created or consumed. The applicable
material balance equations with the feeds and products of component i ,definedas F i
and P i , respectively, are for a reactant. For example, if i is component A,

P i = F i − aX (10.3)

and for a reaction product, for example, if i is component D,

P i = F i + dX (10.4)

This is illustrated at Chapter Ten Examples/RStoicExample and is shown in Figure 10.1.
Here a duplicator block feeds each RStoic reactor block. The reaction involved is the
formation of ammonia from hydrogen and nitrogen. The reactor ST1 is configured for
an extent of reaction of 90 lbmol/hr and reactor ST2 with a fraction converted of 0.50
nitrogen. The details of the extent of reaction configuration is shown in Figure 10.2.

11

ST1

21

D1

1

DUPL

12 ST2

22

Figure 10.1 RStoic example.

Figure 10.2 Configuration of extent of reaction.