A fresh feed stream containing A and B joins a recycle stream and the combined s

Question

A fresh feed stream containing A and B joins a recycle stream and the combined stream is fed to a reactor. The reactor outlet stream flows at a rate of 222 moles/min and contains 50 wt% A, 20 wt% B, and the balance C. This stream enters a cooler in which most of the C is condensed. The liquid C condensate is withdrawn as a product, and the gas stream leaving the condenser (which contains A, B, and 10 mole% uncondensed C vapor) is the recycle stream that combines with the fresh feed. The molecular weights of the species are as follows: MW_A = 30 g/mol; MW_B = 10 g/mol; MW_C = 35 g/mol. Determine: The total flow rate (in mol/min) and composition (in mole fractions) of the fresh feed stream. The mass flow rates (in kg/hr) of each of the components in the recycle stream. The single-pass conversion of B. The sum of the total molar flow rates (in mol/min) of both streams exiting the condenser. The molar flow rates (in mol/min) of each of the components in the stream entering the reactor.

Explanation / Answer

Flow rate of reactor outlet stream= 222 moles/min

It contains 50 wt%A, 20 wt% B and rest C. Moles of A= 222*0.5= 111,   moles of B= 222*0.2= 44.4 moles/min and C= 222-111-44.4=66.6

After sepearation, uncondensed C = 66.6*0.1= 6.66 moles/min

After condensation, stream flow rates ( mol/min) : A= 111, B= 44.4 and C= 6.66

Moles of C formed =    66.6-6.66= 59.94 moles/min. Rest of the C is recycled.

From the stoichiometry of the reaction , 2 moles of C requires 1.5 moles of A and 2.5 moles of B.

59.94 moles of C required 59.94*1.5/2 moles o A =45 moles of A and 59.94*2.5/2 =75 moles of B

Fresh feed contains A= 45/(45+75) = 0.375 and B= 1-0.375=0.625

Recycle stream contains ( moles/min) A=111, B= 44.4 and C= 6.66

Mass= Moles* molar mass

Recycle stream contains ( gm/min) A= 111*30=3330 gm= 3.33 Kg, B =44.4*10= 444 gm= 0.444 Kg and C= 6.66*35=233.1 gm= 0.2331 Kg

A entering the rectot = Fresh feed + recycle = 111+45= 156 , B= 44.4+45= 89.4,

Moles of B required to produce = 59.94 moles of B= 59.94*5/4= 75 moles of B

C= 6.66 moles/min

Percent conversion = 100*75/89.4= 84%

Reactor inlet contains : A :156 , B: 89.4, C= 6.66 , total flow = 156+89.4+6.66 =252

Composition at the inlet : A =156/252= 0.62, B= 89.4/252=0.35, C= 1-0.62-0.35=0.03

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.