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Previous Year Exam Questions of Fluidization Engineering of bput - FE by Bput Toppers

  • Fluidization Engineering - FE
  • 2018
  • PYQ
  • Biju Patnaik University of Technology BPUT - BPUT
  • Chemical Engineering
  • B.Tech
  • 14 Offline Downloads
  • Uploaded 8 months ago
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Registration No : Total number of pages : 03 B.Tech. PCE6J002 6th Semester Regular Examination 2017-18 FLUIDIZATION ENGINEERING BRANCH : CHEM Time : 3 Hours Max Marks : 100 Q.CODE : C333 Answer Part-A which is compulsory and any four from Part-B. The figures in the right-hand margin indicate marks. Assume suitable notations and any missing data wherever necessary. Answer all parts of a question at a place. Q1. (a) (b) (c) (d) (e) (f) Part – A (Answer all the questions) Answer the following questions : (2 x 10) How the liquid behaves across the fluidized bed, when the velocity is more than the minimum fluidization? i. Bubbles formation ii. Slugs formation iii. No bubbles iv. None of these Calcinations of limestone and dolomite takes place at which temperature (degree Celsius)? i. 200 ii. 500 iii. 1000 iv. 2000 What is the mesh size of coal used in winker gas generator? i. <8 ii. >8 iii. <16 iv. >16 What is the range of Reynolds number (Re) for large particles in the fluidization bed? i. Re < 20 ii. Re > 20 iii. Re > 1000 iv. 20 > Re < 1000 What is the most important factor to be considered for designing a fluidized bed reactor? i. Diameter of reactor ii. Height of reactor iii. Size distribution of solids iv. Gas flow rate In pneumatic transport, explain the importance of the classification of solids before its application has been started? i. Any kind of solids’ range can be transported ii. Only Geldart ‘A’ and ‘B’ particles can be transported iii. Only Geldart ‘C’ and ‘D’ particles can be transported iv. Only Geldart ‘A’ and ‘D’ particles can be transported

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(g) (h) (i) (j) Q2. (a) (b) (c) (d) (e) (f) (g) (h) (i) (j) Q3. (a) (b) (c) Q4. (a) (b) In case of a heavy bed, which type of distributor can withstand its weight? i. Flat ii. Convex iii. Concave iv. Concavo-convex How to distinguish between Entrainment and Elutriation? i. Based on segregation of particles ii. Based on velocity of gas iii. Based on height of reactor iv. All of these For particles to not reach the TDH, what is the condition required? i. Ut<Uo ii. Ut>Uo iii. Ut = Uo iv. Ut<=Uo When the diameter is narrower of the bed, which kind of problem is most likely to occur in the bed? i. Channeling ii. Slugging iii. Entrainment iv. None of these (2 x 10) Answer the following questions : Write the industrial applications of fluidized beds. Write a short note on Slugging fluidized bed. Define a spouted bed with a neat diagram. Describe the pressure drop vs. velocity diagram for uniformly sized particles. Define terminal velocity of the particles. Write a short note on wake region at bubbles. What is pneumatic transport of solids in fluidized beds? Define FBH and TDH in fluidized beds. What is the mechanism of ejection of solids from a fluidized bed into the free board? What are the different variables affecting the heat transfer rate in fluidized beds? Part – B (Answer any four questions) With the help of neat sketches explain the Fluidization process. Discuss the advantages of fluidized beds used for industrial operations. With the help of neat sketches explain the operations of various types of Fluidized Bed Dryers. Explain the effects of Pressure and Temperature on bed properties of a Fluidized Bed. Discuss the Geldart’s classification of particles with neat diagram and provide suitable examples as well. (4) (3) (8) (5) (10)

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Q5. Define minimum fluidization velocity. Derive an expression to obtain the minimum fluidization velocity in case of a Fluidized Bed. Calculate the minimum fluidizing velocity for a bed of large particles. i. Use the information given for ∈ and ∅ . ii. Do not use information on ∈ and ∅ . Data : Solids : = 2.93 g/cm3, dp = 1mm,∅ = 0.75, ∈ = 0.5 Gas : = 0.01 g/cm3 , = 0.0003 g/cm.s (10) Explain the need for providing distributor in fluidized beds. Describe the different types of distributors used in industrial scale. A shot of gas is injected into a 60 cm ID incipiently fluidized bed of 300 m sand for which Umf = 3 cm/s and ∈ = 0.5. A 5 cm bubble forms. Determine i. The rise velocity of the bubble. ii. The cloud thickness about the bubble. (10) Q7. Draw the sketches of gas streamlines near a single rising bubble for Davidson model and explain in detail.Show slow cloudless bubble and fast clouded bubble. Compare Davidson model with other models for gas flow at bubbles. (15) Q8. Explain and differentiate the overall bed coefficient and local coefficient with respect to mass transfer in case of fluidized bed. Develop an expression for mass transfer rate from the Bubbling bed model. (15) Describe the counter flow solid circulation model for the vertical movement of solid in a bubbling fluidized bed. Discuss the experimental findings for emulsion movement of small and fine particles with neat diagrams in a fluidized bed. (5) (a) (b) Q6. (a) (b) Q9. (a) (b) (5) (5) (10)

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