Consider a chemical process to produce benzene at a rate of 9 5 0 0 k g h r with product benzene ( purity 9 9 7 ) A process based on hydroalkylation ( HAD ) is considered Figure 1 shows a simplified PFD diagram for HDA process The basic unit operations of this process reactor, furnace, vapor liquid separator, recycle compressor, two heat exchangers and three distillation columns Two raw materials, hydrogen and toluene, are converted into benzene ( main product ) , with methane and diphenyl produced as by products The two vapor phase reactions are C 7 H 8 H 2 C 6 H 6 C H 4 ( 1 ) 2 C 6 H 6 C 1 2 H 1 0 H 2 ( 2 ) The kinetic rate expressions are functions of the partial pressure ( in psia ) of toluene P T o , hydrogen P H , benzene P B z and diphenyl P D p , with an Arrhenius dependence and given as r 1 3 6 8 5 8 1 0 6 exp ( 2 5 , 6 1 6 T ) P T o P H 0 5 , H r x n 2 1 , 5 0 0 B t u l b r 2 5 9 8 7 1 0 4 exp ( 2 5 , 6 1 6 T ) P B Z 2 2 5 5 3 1 0 6 exp ( 2 5 , 6 1 6 T ) P D p P H , H r x n 0 Where r 1 and r 2 have units of Ibmo l m i n f t 3 and T ( K ) Equilibrium constant for reaction 1 ( T is in K ) l n k p 1 3 5 1 5 0 3 7 T 2 0 7 3 l n T 3 4 9 9 1 0 4 T 4 1 3 7 1 0 8 T 2 3 0 1 7 T 2 The flowsheet and key process streams for the process is given in Figure 1 and Table 1 i Plot input output structure and Asses the economic potential of the process ii Determine the conversion of ethanol iii The yield of benzene based on toluene iv The selectivity of diphenyl for toluene v The benzene recovery vi Evaluate the equilibrium conversion of toluene at 1 1 5 0 F ( consider only reaction 1 ) vii If the amount of hydrogen in the feed to the reactor is reduced to the stoichiometric amount determine the effect on the equilibrium conversion at 1 1 5 0 F viii Discuss the importance of presence of the furnace on the reaction rate of both reactions

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Consider a chemical process to produce benzene at a rate of 9 5 0 0 k g h r with product benzene ( purity 9

Consider a chemical process to produce benzene at a rate of

9500 k \frac{g}{h} r

with product benzene

(

purity

99.7 %) .

A process based on hydroalkylation

(

HAD

)

is considered. Figure

1

shows a simplified PFD diagram for HDA process. The basic unit operations of this process: reactor, furnace, vapor liquid separator, recycle compressor, two heat exchangers and three distillation columns. Two raw materials, hydrogen and toluene, are converted into benzene

(

main product

),

with methane and diphenyl produced as by products. The two vapor

-

phase reactions are:

C_{7} H_{8} + H_{2} C_{6} H_{6} + C H_{4} (1)

2 C_{6} H_{6} C_{12} H_{10} + H_{2} (2)

The kinetic rate expressions are functions of the partial pressure

(

in psia

)

of toluene

P_{T o},

hydrogen

P_{H},

benzene

P_{B z}

and diphenyl

P_{D p},

with an Arrhenius dependence and given as

r_{1} = 3.6858 10^{6}

exp

(\frac{- 25, 616}{T}) P_{T o} P_{H}^{0.5}, H_{r x n} = - 21, 500 \frac{B t u}{l b}

r_{2} = 5.987 10^{4}

exp

(\frac{- 25, 616}{T}) P_{B Z}^{2} - 2.553 10^{6}

exp

(\frac{- 25, 616}{T}) P_{D p} P_{H}, H_{r x n} = 0

Where

r_{1}

and

r_{2}

have units of Ibmo

\frac{l}{m} i n . f t^{3}

and

T (K) .

Equilibrium constant for reaction

1 (T

is in

K)

l n k_{p} = 13.51 + \frac{5037}{T} - 2.073 l n T + 3.499 10^{- 4} T + 4.137 10^{- 8} T^{2} + \frac{3017}{T^{2}}

The flowsheet and key process streams for the process is given in Figure

1

and Table

1 .

.

Plot input

-

output structure and Asses the economic potential of the process.

.

Determine the conversion of ethanol.

iii. The yield of benzene based on toluene.

.

The selectivity of diphenyl for toluene.

.

The benzene recovery.

.

Evaluate the equilibrium conversion of toluene at

1150 F . (

consider only reaction

1) .

vii. If the amount of hydrogen in the feed to the reactor is reduced to the stoichiometric amount determine the effect on the equilibrium conversion at