More Questions from Mechanical Operations

For handling hot, abrasive “ash” and similar residues from boilers and furnaces, which conveyor type is generally the most suitable and robust choice?

Chemical Engineering Mechanical Operations Difficulty: Easy
Choose an option
  • A
    Flight (scraper) conveyor
  • B
    Drag or slat conveyor
  • C
    Belt conveyor
  • D
    Ribbon conveyor
  • E
    Pneumatic dilute-phase conveyor

Answer

Correct Answer: Flight (scraper) conveyor

Explanation

Introduction / Context:Ash handling demands equipment that tolerates abrasion, elevated temperature, and sometimes wet/slurry conditions. The conveyor must provide positive displacement transport with minimal spillage and high wear resistance.

Given Data / Assumptions:

  • Material: hot, abrasive ash or clinker-like residues.
  • Operating environment: harsh, often at boiler/furnace discharge.
  • Goal: reliable, contained conveyance.

Concept / Approach:Flight (scraper) conveyors drag material along the bottom of a trough using flights fixed to chains. This positive mechanical conveying is suited to abrasive, hot materials, allowing cooling sections or quench baths. Belt conveyors are vulnerable to abrasion and heat; ribbon conveyors suit mixing, not bulk transfer; dilute-phase pneumatic systems risk erosion and dust control issues.

Step-by-Step Solution:

Match material severity (hot, abrasive) to conveying principle: chain-and-flight design.Evaluate alternatives: belts wear rapidly; ribbons mix; pneumatic lines erode and dust handling is complex.Select the robust option: flight (scraper) conveyor.

Verification / Alternative check:Power plants and foundries widely use submerged scraper conveyors or dry flight conveyors for bottom ash and clinkers, confirming the selection.

Why Other Options Are Wrong:

Drag/slat is related and can be used, but “flight (scraper)” is the canonical ash-handling choice in many designs.Belts lack heat and abrasion resistance for continuous ash duty.Ribbon conveyors are mixers, not bulk conveyors.Pneumatic dilute-phase risks severe pipeline erosion and dust control challenges.

Common Pitfalls:Overlooking temperature limits of belts; underestimating abrasion on pneumatic elbows; confusing slat with scraper terminology without considering specific ash system design.

Final Answer:Flight (scraper) conveyor

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