화공계산 시험문제 2017. 6.5 기말
1. Nitric acid (HNO3) that is used industrially for a variety of reactions can be produced by the reaction of ammonia
(NH3) with air by the following overall reaction:
NH3 (g) + 2 O2 (g)→ HNO3 +H2O
The product gas from such a reactor has the following composition (on a water free basis)
0.8% HN3, 9.5% HNO3, 3.8% O2, 85.9% N2
Determine the percent conversion of NH3 (10 points) and the percent excess air used (10points).
2. A power company operates one of its boilers on natural gas and another on oil. The analyses of the fuels show
96% CH4, 2% C2H2, and 2% CO2 for the natural gas and CnH1.8`n for the oil. The flue gases from both groups
enter the same stack and an Orsat analysis of the combined flue gas shows 10% CO 2, 0.63% CO, 4.55% O2 and
84.82% N2 gas. Calculate the amount of oil (mol) if 100mol of natural gas is used. (20 points)
3.
The process in the figure is the dehydrogenation of propane (C3H8) to propylene (C3H6) according to the
reaction
C3H8 → C3H6 + H2
The conversion of propane to propylene based on the total propane (fresh + recycle) feed into the reactor at F2 is
40%. The product (F5) is 50 kgmol for 1 hour.
(a) Calculate fOA and fsp (10 points)
(b) Calculate extent of reaction (10 points)
(c) Calculate all the six (F1~F6) in kg mol for 1 hour (10 points)
100% H2
fresh
C3H8
F1
F2
F3
Catalytic
reactor
F6
80% C3H8
20% C3H6
Separator
100%C3H6
feed
F4
F5
4. The analysis of a coal indicates 75wt% C, 17wt% H, 2wt% S (M.W. =32), and 6wt% non-combustible ash.
The coal is burned at a rate of 5000 kg/h, and the feed rate of air to the furnace is 50 kmol/min. All of the ash
and 6% of the carbon in the fuel leave the furnace as a molten slag; the stack gas is composed of O 2, N2, CO,
CO2, SO2, and H2O. The selectivity of CO2 to CO production is 10:1.
a) Calculate the percent excess air fed to the reactor (10 points)
b) Calculate the mole fractions of SO2 in the stack gas. (10 points)
c) If the emitted SO2 is converted to acid rain (H2SO4) in the following reactioins, calculate the rate of formation
of sulfuric acid (kg/h) ? (10 points)
<보너스 문제> 인하대학교 교가 (보너스 1점: 모두 맞아야 1점임)
(a)
(b)
(c)
<주의 사항>
1. 답안지는 깨끗하게 정리하여 쓸 것. (답 밑에 밑줄을 긋고 반드시 답이라고 표시할 것)
2. 학번, 이름 반드시 확인하고 답안지에 쓸 것. (답안지는 2장까지 사용 가능)
3. 빨간색 펜은 절대 사용하지 말 것
4. 시험성적 및 학점은 반드시 찾아와서 물어볼 것 (e-mail 또는 전화로 물어 보지 말 것.)
5. 공시된 학점은 이의신청 검토 이후 점수가 다시 반영되므로 최종학점과 다를수 있음.
(본 과목은 김영란법에 따라 학점에 대한 어떠한 편의도 제공되지 않으며 오직 학칙에 따라 모든 학생에게 동일한 판단
기준으로 성적이 부여됩니다. 따라서 학점 조정을 위한 어떠한 시도도 거부합니다.)

한학기 동안 수고 많았습니다.