课程名称︰质能平衡甲 课程性质︰系定必修 课程教师︰蔡伟博 开课学院：工学院 开课系所︰化学工程系 考试日期（年月日）︰2008年5月13日 考试时限（分钟）：1330~1510（100分钟） 是否需发放奖励金：是，谢谢 （如未明确表示，则不予发放） 试题 : 1.Brief questions (10 points) (A) Gibbs phase rule (B) Absolute saturation (C) Henry’s law (D) Critical temperature 2.(20 points) 1000 kg of a 30.0% solution of acetone in water and a second stream of pure methyl isobutyl ketone (MIBK) is fed to a mixer. The mixture is then fed to a settler where two phases form and are withdrawn separately at 25oC. If the acetone concentration in water-rich phase is half of the acetone concentration in MIBK-rich phase, how much MIBK must be fed to the process, assuming that the fluids remain in the settler long enough for equilibrium to be achieved? what percentage of the acetone is transferred from the water to the MIBK? 3.(20 points) A local utility burns coal having the following composition on a dry basis. Component Percent C 83.05 H 4.45 O 3.36 N 1.08 S 0.70 Ash 7.36 Total 100.0 The average Orsat analysis of the gas from the stack during a 24-hour test was Component Percent CO2+SO2 15.4 CO 0.0 O2 4.0 N2 80.6 Total 100.0 Moisture in the fuel was 3.90%, and the air on the average contained 0.0048 lb H2O/lb dry air. The refuse showed 14.0% unburned coal, with the remainder being ash. You are asked to check the consistency of the data before they are stored in a database. Is the consistency satisfactory? What was the average percentage excess air used? 4. (20 points) Dry ice (solid CO2) has been used as a mine explosive in the following manner. A hole is drilled into the mine wall, filled with dry ice plus a small charge of gun powder, and then plugged. The gun powder is lit with a fuse, vaporizing the CO2 and building up an explosively high pressure within the hole. Use the compressibility-factor equation of state to estimate the pressure that will develop if 5.00 g of dry ice is placed in a 50.0-mL hole and heated to 1000 K. (For CO2: Tc=304.2 K, Pc=72.9 atm) 5. (20 points) To condition the air in an office building in the winter, 1000 m3 of moist air per hour at 101 kPa and 22oC with a dew point of 11oC enter the system. The air leaves the system at 98 kPa with a dew point of 58oC. How many kilograms of water vapor are added to each kilogram of wet air entering the process? P*H20(11oC) = 9.84 mmHg, P*H20(58 oC) = 136.1 mmHg 6. (20 points) Ethylene oxide is produced by the catalytic oxidation of ethylene: 2 C2H4 + O2 -----> 2 C2H4O An undesired competing reaction is the combustion of ethylene: C2H4 + 3 O2 -----> 2 CO2 + 2 H2O The feed to the reactor contain 3 moles of ethylene per mole of oxygen. The single-pass conversion of ethylene is 20%, and for every 100 moles of ethylene consumed in the reactor, 90 moles of ethylene oxide emerges in the reactor products. A multiple-unit process is used to separate the products: ethylene and oxygen are recycled to the reactor, ethylene oxide is sold as a product, and carbon dioxide and water are discarded. Calculate (i) the molar flow rates of ethylene and oxygen in the fresh feed needed to produce 1 ton per hour of ethylene oxide; (ii) the production rate of ethylene oxide; (iii) the overall conversion of ethylene. [Attached figure: "Elementary Principles of Chemical Processes" 3rd edition,by Richard M.Felder Ronald W.Rousseau FIGURE 6.6-1 (p.274) FIGURE 5.4-4 (p.211)] --

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