Unit operations — DU B.Sc. Polymer Science Previous Year Question Papers

(c) A producer gas with the composition by volume, 27.3% CO, 5.4% CO2, 0.6% O2, 66.7% N, is burnt with 20% excess air. If the combustion is 98% complete, calculate the composition by volume of the flue gases. 6. (a) What are condensers and vaporizers ? Discuss two-pass floating-head condenser in detail. (b) Discuss the penetration theory in details. (c) What is crusher? Discuss smooth roll crusher in details. 7. (a) What is filtration ? Discuss factors which affect rate of filtration. (b) Explain Langmuir theory of adsorption. (c) Discuss the double-pipe heat exchangers. Science (UGCF) (c) Attempt six questions in all. 1. (a) What is the purposé of material and energy balance? (b) Discuss the role of diffusion in mass transfer. (c) Write short note on air cooled heat exchanger. (d) Discuss Schmidt number and its significance. (e) Explain Reynolds number. 2. (a) Write short note on azeotropic distillation. (b) The gas acetylene is produced according to the following reaction by treating calcium carbide with water : Calculate the number of hours of service that can' be derived from 1.0 kg of carbide in an acetylene lamp burning 60 litres of gas per hour at a temperature of 20°C and a pressure of 740 mm Hg. (c) What is size reduction. Discuss the working principal of ball-mill and its construction. : 3. (á) Discuss the Henry law and its limitation in details. (b) What is mass transfer phenomenon ? Discuss the "Two film theory" in details. (c) Dry methane is burned with dry air (both are initially at 25°C). The flame temperațure is 1297°C. If complete combustion is assumed, how much excess air is to be used ? Heat of reaction, 4H, =-0.2 × 10° cal. Cp for CO, = 12.37 cal/mol°C Cp for H,O = 9.60 cal/mol°C Cp for N, = 7.68 cal/mol°C Cp for air = 7.74 cal/mol°C 4. (a) What is an adsorption isotherm ? Discuss the various applications of adsorption in details. (b) What is drying ? Illustrate the different stages of drying of moist solid.. (c) Discuss different types of unit operation used in polymer synthesis industry. 5. (a) What is diffusion ? Describe the Fick's law (b) Discuss the plate type heat exchanger with suitable diagram.