Batch sedimentation equipment selection: which device is used specifically for batch sedimentation of solids from liquids?

Introduction / Context:
Sedimentation separates suspended solids from a liquid by gravity. While many thickeners are continuous, laboratory and some plant operations also use batch thickeners/clarifiers to quantify settling behavior or process small campaigns. This question asks you to identify batch sedimentation equipment among gas-solids devices and gas scrubbers that do not employ liquid-solid settling.

Given Data / Assumptions:

• Goal: gravity settling of solids from a liquid.
• Batch operation: feed is charged, allowed to settle, clarified liquid withdrawn.
• Not to be confused with gas-solid collectors.

Concept / Approach:
Dust catchers and cyclones are gas-solid separators; they do not perform liquid-solid sedimentation. Rotary sprayer scrubbers contact gas with liquid to remove contaminants; again, not sedimentation equipment. A thickener (here named as “filter thickener” in the options) is the only item associated with liquid-solid settling, capable of batch operation in smaller units or tests.

Step-by-Step Solution:
Eliminate gas-solid devices: dust catcher and cyclone.Eliminate scrubber: mass transfer, not gravity settling.Select thickener as the batch sedimentation equipment.

Verification / Alternative check:
Jar tests and batch settling tests are standard precursors to thickener design, confirming that batch sedimentation is a recognized mode for thickeners.

Why Other Options Are Wrong:
Dust catcher, cyclone: no liquid phase sedimentation.Rotary sprayer scrubber: contactor, not settler.

Common Pitfalls:
Assuming “filter” implies filtration; a thickener is not a pressure filter—here the term denotes gravity settling.

Final Answer:
Filter thickener