Sieve tray column diameter is governed by_________________?
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Answer: B. Upper limit of the vapour velocity
Explanation
Column diameter is controlled by vapor velocity limits to prevent excessive entrainment of liquid. Exceeding the maximum allowable vapor velocity causes flooding and severe operational instability in columns. Keeping vapor velocity below the critical upper limit ensures stable counter-current gas-liquid contacting. Distillation columns rely on vapor and liquid moving counter-currently through structured or tray internals. Sieve trays contain numerous small perforations through which vapor rises continuously into the liquid pool. Flooding occurs when excessive upward vapor drag prevents downward liquid flow through the trays.
Chemical engineers calculate column diameters carefully during the initial mechanical and process design phase. Selecting the correct diameter prevents costly tower flooding and ensures high separation efficiency. Petroleum refineries and chemical plants depend on stable column hydraulics for continuous chemical production. The lower limit of vapor velocity governs weeping rather than the overall cross-sectional column diameter. Hole diameter dictates tray performance and weeping characteristics instead of setting the main column shell size. Plate spacing affects overall tower height and liquid disengagement rather than the primary column diameter.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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