Which equipment is commonly used to remove dispersed water (moisture) from lubricating oil in refinery or lube-conditioning service?
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ATubular centrifuge
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BClarifier (gravity settling only)
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CSparkler (plate) filter
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DVacuum leaf filter
Answer
Correct Answer: Tubular centrifuge
Explanation
Introduction / Context:Water contamination in lubricating oils reduces film strength, promotes corrosion, and accelerates oxidation. Efficient separation of water droplets from viscous oils is essential in maintenance and refining operations.
Given Data / Assumptions:
- Oil contains dispersed water (emulsified or fine droplets).
- We need a continuous, compact device with high g-force.
Concept / Approach:Tubular-bowl centrifuges produce very high centrifugal accelerations, rapidly separating water from oil based on density difference. Gravity clarifiers are too slow for fine droplets; sparkler and vacuum leaf filters remove solids, not immiscible liquid droplets. Coalescers may also be used, but among listed options, the tubular centrifuge is the standard choice.
Step-by-Step Solution:Identify separation type: liquid–liquid (immiscible) with fine droplets.Match to equipment: high-g centrifuge enhances droplet migration.Select tubular centrifuge.
Verification / Alternative check:Lube oil purifiers often employ disc-stack/tubular centrifuges for water removal.
Why Other Options Are Wrong:Clarifier: too slow for fine dispersion.Sparkler/Vacuum leaf: solid–liquid filtration devices, not suited to separating water droplets from oil.
Common Pitfalls:Assuming any filter removes water; filters generally target solids unless paired with coalescing media.
Final Answer:Tubular centrifuge