Process Calculations GATE-1998
Q 1: Pure ethanol vapor is fed to a reactor packed with Alumina catalyst, at the rate of 100 kmol/h. The reactor products comprise Ethylene 95 kmol/h, water vapor 97.5 kmol/h, and diethyl ether 2.5 kmol/h. The reaction occurring can be represented by:
C_2H_5OH\rightarrow C_2H_4+H_2O 2C_2H_5OH\rightarrow C_2H_5OC_2H_5+H_2OThe percent conversion of ethanol in the reactor is:
Q 2: A sample of well water contains 140 g/m3 Ca2+ ions and 345 g/m3 Na+ ions. The hardness of the sample of water, expressed in terms of equivalent CaCO3 in g/m3 (assuming atomic masses of Ca:40, Na:23, C:12, and O:16) is
Q 3: Ethylene Oxide is produced by the oxidation of Ethylene over a catalyst. Safety considerations dictate that the gaseous mixture entering the reactor should contain 10 mol air per mol Ethylene. The conversion per pass is 22 %. The Ethylene oxide formed is completely condensed out and the remaining gases are recycled. Make-up oxygen is added to maintain the requisite oxygen levels. For a plant producing 440 kg/h of Ethylene-oxide, (i) Calculate the quantity of pure makeup oxygen to be supplied, in kg/h, in steady-state operation. (ii) Draw a neat block diagram showing the major units, flows, and compositions. Indicate the envelope boundary around which the requisite mass balance(s) is/are being made. The relevant reaction is represented by
2C_2H_4(g)+O_2(g)\rightarrow2C_2H_4OQ 4: 1000 kg/h of an aqueous solution of 20 % Na2CO3 is cooled gradually to t0 C to crystallize out Na2CO3.10H2O. The solubility of Na2CO3 at t0 C is 2.1 %. Calculate the percentage of Na2CO3 recovered in the form of crystals. (Assume no loss of Na2CO3 through the mother liquor adhering to the crystals and no carryover of crystals with the mother liquor). Draw a neat block diagram showing the inlet and exit compositions and flow rates. (The molecular weight of Na2CO3 can be assumed to be 106).