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Reg. No. : .................................... Name : .........................................
Third Semester B.Tech. Degree Examination, November 2009 (2003 Scheme) 03-306 : PROCESS CALCULATIONS (H) Time : 3 Hours
Max. Marks : 100 PART – A
Answer all questions. Each question carries 4 marks. 1. How is specific gravity measured ? Mention 4 different specific gravity scales. 2. Explain Henry’s law. When is it used ? 3. Convert 5 N H3 PO4 to gm per litre. 4. With suitable mathematical equations explain steady and unsteady state processes. 5. A solution is concentrated from 20% to 40%. How much amount of water is evaporated ? 6. Explain Trouton’s rule and Kopps rule. 7. What is meant by ORSAT Analysis ? 8. Show the effect of temperature on heat of a chemical reaction. 9. Explain the purging operation giving a suitable example. 10. Obtain a relation between Cp and Cv.
P.T.O.
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PART – B Answer any one question from each Module. Module – I 1. A gaseous mixture analysing by volume 10% methane, 30% ethane and the rest hydrogen at 15° C and 1.5 × 105 N/m2 absolute pressure is flowing through an equipment at the rate of 2.5 m3 per minute. Calculate : a) Average molecular weight of the mixture b) Weight percent of each component in the mixture c) Mass flow rate of the mixture in kg per minute.
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2. a) Estimate the molar volume of CO 2 at 500 K and 100 bar using the Vander Waals equation of state Vander Waals constants are 0.364 m4 N/mol2 and 4.267 × 10–5 m3/mol. 10 b) Differentiate between molality, molarity and normality.
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c) Sulphur trioxide gas is obtained by the combustion of iron pyrites (FeS2) according to the reaction 4 FeS2 + 15O 2 → 2 Fe2O3 + 8SO3 . How many kg of pyrites is burned to obtain 100 kg of sulphur trioxide ? How many kg oxygen is consumed in the production of 50 kg SO3 ? (Atomic wt. of iron = 55.85)
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Module – II 3. Vapour pressure of acetone at 273 K is 8.52 kPa and that at 353 K is 194.9 kPa. Dry air initially at 101.3 kPa and 300 K is allowed to get saturated with the vapors of acetone at constant temperature and volume. Determine : a) the final pressure of the mixture and b) the mole percent of acetone in the final mixture. Assume that Clausius-Clapeyron equation is applicable to acetone.
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4. a) Define : a) Relative humidity b) Percentage humidity c) Dew pt.
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b) A solution of potassium dichromate in water contains 13% K2 Cr2 O7 by wt. 1000 kg of this solution is evaporated to remove some amount of water. The remaining solution is cooled to 20° C. If the yield of crystals is 80%, calculate the amount of water evaporated. Solubility of K2 Cr2 O7 is 0.390 kg mol per 1000 kg of water at 20° C. 14 Module – III 5. Methanol is produced by the reaction of CO with H2. Only 15% of CO is converted to methanol. The methanol is condensed and separated from the reacted gases which are recycled. The feed to the reactor contains 2 moles of hydrogen for every mole of CO. The fresh feed enters at 35° C and 300 bar. To produce 6600 kg/hr of methanol, a) Calculate the volume of fresh feed gas 20
b) Find the recycle ratio. 6. NH3 oxidation occurs as per the reaction 4 NH3 (g) + 5O2 (g) → 4 NO(g) + 6 H2O(g) ΔH R = − 226 kJ / mol of NO
NH3 at 100 mol/hr and O2 at 200 mol/hr both at 25° C are fed to a reactor in which the above reaction takes place. The product stream leaves the reactor at 300° C. Calculate the heat transferred from the reactor assuming the reactor operates at 1 atm. Data CPmO = 30.8 J/mol °C, CPm NO = 30.74 J/mol °C 2
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CPm H2O = 34.8 J/mol °C. ———————