Page 149 - Analysis, Synthesis and Design of Chemical Processes, Third Edition

For the toluene hydrodealkylation process, establish the primary flow pathway for
a. Toluene between the feed (Stream 1) and the reactor
b. Benzene between the reactor and the product (Stream 15)
Hint: Consider only one unit of the system at a time. Refer to Figure E5.1.

Figure E5.1 Primary Chemical Pathways for Benzene and Toluene in the Toluene Hydrodealkylation
Process (Figure 1.3)

Toluene Feed: Tactic 1 is applied to each unit operation in succession.

a. Toluene feed Stream 1 mixes with Stream 11 in V-101. A single unidentified stream leaves tank
V-101 and goes to pump P-101. All the toluene feed is in this stream.
b. Stream 2 leaves pump P-101 and goes to mixer m-102. All the feed toluene is in this stream.
c. A single unidentified stream leaves mixer m-102 and goes to exchanger E-101. All the feed
toluene is in this stream.
d. Stream 4 leaves exchanger E-101 and goes to heater H-101. All the feed toluene is in this stream.
e. Stream 6 leaves heater H-101 and goes to reactor R-101. All the feed toluene is in this stream.

Benzene Product: Tactic 2 is applied to each unit operation in succession.
a. Product Stream 15 leaves exchanger E-105.
b. Entering exchanger E-105 is an undesignated stream from s-103 of the distillation system. It
contains all of the benzene product.
c. Apply Tactic 3 and treat the tower T-101, pump P-102, exchangers E-104 and E-106, vessel V-
104, and splitter s-103 as a system.
d. Entering this distillation unit system is Stream 10 from exchanger E-103. It contains all the
benzene product.
e. Entering exchanger E-103 is Stream 18 from vessel V-103. It contains all the benzene product.
f. Entering vessel V-103 is an undesignated stream from vessel V-102. It contains all the benzene
product.
g. Entering vessel V-102 is an undesignated stream from exchanger E-102. It contains all the

benzene product.
h. Entering exchanger E-102 is Stream 9 from reactor R-101. It contains all the benzene product.