fluid bed dryer interview questions

This set of Fluidization Engineering Interview Questions and Answers for Experienced people focuses on “Synthesis Reactions-2”.

1. Why was fluidized bed not used commercially for production of gasoline from natural gas? a) Conversion was below par b) Scale-up was difficult c) Back-mixing d) All of the mentioned View AnswerAnswer: d Explanation: Fluidized bed was not possible because of less conversion, scale up problem.

2. Why was conversion in the production of gasoline in fluidized bed was less? a) Back-mixing and by-passing b) Recycling c) Regeneration d) None of the mentioned View AnswerAnswer: a Explanation: Back-mixing and by-passing are undesirable for gasoline production.

3. What is the main reason for lower efficiencies in the commercial operations of synthetic reactions through fluidized beds? a) Gas bypassing b) Backing mixing c) Bubble behaviour d) All of the mentioned View AnswerAnswer: d Explanation: Serious gas by-passing, back mixing and irregular bubble behaviour leads in lowering the efficiencies in fluidized beds.

4. Why are electrodes placed in resistance-heated fluidized bed? a) Achieve high temperatures b) Acts as heat transfer surface c) Helps in magnetizing the metallic particles d) None of the mentioned View AnswerAnswer: a Explanation: To maintain very high temperatures through passing high density current through electrically conductive material.

5. Operating conditions and feed ratios are different for all these processes, however, conversion of limiting reagent, acetic acid is roughly 50-70%, true or false? a) True b) False View AnswerAnswer: a Explanation: Based on experiments conducted by Du pont company.

6. In the dilute phase reacting system, reacting gases carry suspended catalyst through tubes of a vertical heat exchanger with velocity of? a) 3 to 12 m/s b) 12 to 24 m/s c) 1 to 3 m/s d) 0.1 to 10 m/s View AnswerAnswer: a Explanation: This range of velocity provides relevant driving force for smooth circulation of powdered catalyst.

7. What is the mesh range that the catalytic reactor for vinyl acetate developed by Du pont uses? a) 30 to 150 mesh b) 150 to 200 mesh c) 10 to 50 mesh d) 200 to 300 mesh View AnswerAnswer: a Explanation: Optimum range to prevent elutrition and avoiding bubble cap blockage.

8. Kellogg company developed a synthetic gasoline plant based on dilute phase transfer line, works on the principle of circulation system for the solids, true or false? a) True b) False View AnswerAnswer: a Explanation: They developed such fluidized bed which works on principle of circulation system for solids.

9. In Sohio process, after fluidized bed, instead of several separation units, why cant we use a single distillation column? a) Difficult to separate b) Economics c) Space factor d) None of the mentioned View AnswerAnswer: a Explanation: Since the boiling points of the end products are very close, distillation columns cannot be used to separate them.

10. What is the role of cone shaped structure in the Du pont catalytic reactor? a) Gas distribution b) To occupy empty space c) To prevent attrition d) For better fluidization View AnswerAnswer: a Explanation: Cone helps in gas distribution for better gas-solid contact and eliminate gas bypassing.

To practice all areas of Fluidization Engineering for Interviews, here is complete set of 1000+ Multiple Choice Questions and Answers. «

10 Interview Questions/ Answers for FBD, Granulation in Pharmaceutical, know about FBD, it’s Working

Question #5: Compared to cartridge filters, bag filters are much better at retention. True or False?

Last week Freund-Vector created a short quiz on Fluid Bed Processors on LinkedIn. The purpose of this quiz was to test customer’s knowledge on Freund-Vector’s Fluid Bed technology and processing capability. There was an overwhelming response and we appreciate everyone’s responses. We now would like to share the answers to those questions.

Good luck on the upcoming quizzes on Spray Drying, Roller Compact, and Film Coating. We look forward to reviewing your responses on LinkedIn.

Question #2: To determine the batch size when utilizing a Fluid Bed process, you would need to know the following:

Parameters to be controlled in fluidized bed dryers (system)

In order to improve operation, efficiency, and reproducibility of a fluidized bed dryer, some parameters need to be controlled. These parameters are categorized into:

  • Apparatus parameters: Those controlled by the equipment.
  • Process parameters: Those controlled by the process.
  • Product parameters: Those controlled by the product.
  • Position of the air distribution plate: This parameter influences the pattern.
  • Shape of the instrument: The annular based design gives a better product.
  • Nozzle height: Nozzle height plays a vital role when fluidized bed dryers are used as a coating machine. The atomized coating solution should not get dried before reaching the tablet surface.
  • Temperature: Increased temperature leads to increased moisture diffusivity and hence increased drying rate and decreased drying time. The nature of the material plays an important role in choosing the operating temperature.
  • Humidity: Faster drying is achieved when the moisture content of the inlet air is maintained at its minimum.
  • Airflow rate/gas velocity: Increasing gas velocity increases drying rate but should be maintained at an optimized rate (not to fast or too slow). Gas velocity has no effect on particles with high internal resistance to moisture transfer.
  • Moisture content of the feed material.
  • Feed rate/batch size.
  • Product moisture content.
  • Particle size, shape, and diameter.
  • Types of Fluidized-Bed Dryers

    There are various types of fluidized bed dryer and an individual’s familiarity with the specific characteristics of these various types enables one to make a logical and cost-effective selection of fluidized bed dryer for a drying operation.

    In many instances, several different types may provide similar performance at the same cost. It should be noted also that not all modified fluidized bed dryers are necessarily better than the conventional dryers in terms of product quality, or energy efficiency, or drug performance.

    10. What is the role of cone shaped structure in the Du pont catalytic reactor? a) Gas distribution b) To occupy empty space c) To prevent attrition d) For better fluidization View AnswerAnswer: a Explanation: Cone helps in gas distribution for better gas-solid contact and eliminate gas bypassing.

    1. Why was fluidized bed not used commercially for production of gasoline from natural gas? a) Conversion was below par b) Scale-up was difficult c) Back-mixing d) All of the mentioned View AnswerAnswer: d Explanation: Fluidized bed was not possible because of less conversion, scale up problem.

    This set of Fluidization Engineering Interview Questions and Answers for Experienced people focuses on “Synthesis Reactions-2”.

    8. Kellogg company developed a synthetic gasoline plant based on dilute phase transfer line, works on the principle of circulation system for the solids, true or false? a) True b) False View AnswerAnswer: a Explanation: They developed such fluidized bed which works on principle of circulation system for solids.

    4. Why are electrodes placed in resistance-heated fluidized bed? a) Achieve high temperatures b) Acts as heat transfer surface c) Helps in magnetizing the metallic particles d) None of the mentioned View AnswerAnswer: a Explanation: To maintain very high temperatures through passing high density current through electrically conductive material.

    FAQ

    What is fluid bed dryer principle?

    Fluid bed dryers work on the principle of fluidization, a process where a material is converted from a static solid-like state to a dynamic fluid-like state. In this process, hot gas or air is introduced through a perforated distribution plate into the area holding the material.

    What are the critical parameters of FBD?

    The Principle of Fluidized Bed Dryer:

    At this stage, this solid bed looks like the boiling liquid, therefore this stage is called as fluidized. Use of hot air to fluidizing the bed will increase the drying rate of the material.

    What are the advantages of a fluidised bed dryer?

    Critical Parameters of FBD
    • Inlet Air temperature.
    • Outlet air temperature.
    • Product temperature.
    • Fan motor speed.
    • LOD of product.

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