GUJARAT TECHNOLOGICAL UNIVERSITY
BE- SEMESTER-V (NEW) EXAMINATION - WINTER 2020
--- Content provided by FirstRanker.com ---
Subject Code:3153617 Date:27/01/2021Subject Name:Basics of Mass Transfer
Time:10:30 AM TO 12:30 PM Total Marks: 56
Instructions:
1. Attempt any FOUR questions out of EIGHT questions.
--- Content provided by FirstRanker.com ---
2. Make suitable assumptions wherever necessary.3. Figures to the right indicate full marks.
MARKS
Q.1 (a) Define: (a) HETP (b) Humid Heat (c) Reflux ratio 03
(b) Mention the factors affecting choice of separation method. 04
--- Content provided by FirstRanker.com ---
(c) Explain in detail about various application of mass transfer 07 Q.2 (a) Explain in brief about Azeotropic distillation. 03
(b) Explain temperature and pressure dependency of diffusivity 04 of gases and liquids.
(c) Derive the relation for steady state molecular diffusion in 07 fluids at rest and in laminar flow.
Q.3 (a) Write short note on Absorption factor. 03
--- Content provided by FirstRanker.com ---
(b) Define Diffusivity and state its assumptions for penetration. 04(c) Starting from the basics of diffusion, derive the equation to 07 calculate Na for steady state equimolal counter diffusion of A through B for unidirectional binary gas phase.
Q.4 (a) Define relative saturation, percentage saturation and 03 enthalpy.
(b) Write down the selection criteria for the solvent in liquid 04 extraction process.
(c) A gas (B) — benzene.(A) mixture is saturated at 1 std atm, 07 50°C. Calculate the.absolute humidity if B is (a) nitrogen and (b) carbon dioxide: Vapor pressure of nitrogen at 50°C = 0.362 std atm
--- Content provided by FirstRanker.com ---
Q.5 (a) Discuss Raoult’s law for ideal solutions. 03
(b) With respect to interphase mass transfer, explain mass 04 transfer operation between two immiscible phases.
(c) CO2 and Air are in equimolal counter diffusion with each 07 other in the tube of 50 mm diameter and 1 m length. The total pressure is 1 atm and the temperature is 25°C. The partial pressure of CO2 at one end of the tube is 190 mm Hg while at the other end of the tube is 95 mm Hg. Estimate the mass transfer rates (in kg/s) of CO2 and air through the tube. Diffusivity is 0.16 x 10?5 m²/s.
Q.6 (a) Explain in brief about Two resistance theory. 03
(b) Explain with neat sketch the rate of drying curve in detail. 04
--- Content provided by FirstRanker.com ---
(c) Methane diffuses at steady state through a tube containing 07 helium for the case equimolar counter diffusion. At point 1, the partial pressure of methane is 55 kPa and at point 2, 0.03 m apart is 15 kPa. The total pressure is 101.325 kPa and value of diffusivity is 6.75 x 10?5 m²/s. Calculate the partial pressure of methane at point 0.02 m apart from point 1 for the above case. Q.7 (a) Write down the various applications of liquid-liquid 03 extraction.
(b) Discuss the concept with principle of crystallization. 04
(c) A continuous rectification column is used to separate a binary 07 mixture of A & B. Distillate is produced at a rate 100 kmol/h, containing 98 mole% A. In the enriching section the mole fraction of A in the liquid and vapour from two adjacent lates are as follows.
X y
--- Content provided by FirstRanker.com ---
0.65 0.820.56 0.76
If the latent heat of vaporization is same for all mixtures and if the feed is a saturated liquid, calculate 1) Reflux ratio i1) Vapour flow rate in stripping section
Q.8 (a) Write a short note on flash distillation. 03
(b) Explain in brief about Fluidized bed dryer. 04
--- Content provided by FirstRanker.com ---
(c) Compute the vapor-liquid equilibria at constant pressure of 1 07 standard atmosphere for mixtures of n-heptane (A) with n- octane (B), which may be expected to form ideal solutions. Also calculate the relative volatility for each temperature and its average value.T(°C) | 98.4 | 105 | 110 | 115 | 120 | 125.6
p? | 760 | 940 | 1050 | 1200 | 1350 | 1540
p?, ? | 333 | 417 | 484 | 561 | 650 | 760
--- Content provided by FirstRanker.com ---
This download link is referred from the post: GTU B.Tech 2020 Winter Question Papers || Gujarat Technological University
--- Content provided by FirstRanker.com ---