27 real Heat Exchanger & Column Design questions from the Process Design bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is TEMA designation?
Junior
A.tray malfunction at low vapour rate where liquid leaks through the perforations instead of crossing the weir, which sets the turndown limit
B.extra thermal resistance (about 0.0002–0.0005 m²K/W for cooling water) added to the clean coefficient to allow for deposits over the run length
C.packed height equivalent to one theoretical plate, typically 0.3–0.6 m for structured packing; packed height equals stages required times this value
D.three-letter code for front head, shell and rear head types, for example AES meaning removable channel, single-pass shell and split-ring floating head
2. Which term means: "three-letter code for front head, shell and rear head types, for example AES meaning removable channel, single-pass shell and split-ring floating head"?
A.TEMA designation — tray malfunction at low vapour rate where liquid leaks through the perforations instead of crossing the weir, which sets the turndown limit
B.TEMA designation — three-letter code for front head, shell and rear head types, for example AES meaning removable channel, single-pass shell and split-ring floating head
C.TEMA designation — packed height equivalent to one theoretical plate, typically 0.3–0.6 m for structured packing; packed height equals stages required times this value
D.TEMA designation — extra thermal resistance (about 0.0002–0.0005 m²K/W for cooling water) added to the clean coefficient to allow for deposits over the run length
A.trays suit high liquid rates, fouling and large diameters; structured packing gives lower pressure drop and higher capacity for vacuum and low-liquid-load services
B.fixed tubesheet is cheapest but needs an expansion joint and cannot be shell-side cleaned; U-tube absorbs expansion but tube insides are hard to clean; floating head allows both
C.packed height equivalent to one theoretical plate, typically 0.3–0.6 m for structured packing; packed height equals stages required times this value
D.multiplier below 1 applied to counter-current LMTD for multi-pass or cross-flow exchangers; designs with F under about 0.75 need more shells in series
5. Which term means: "multiplier below 1 applied to counter-current LMTD for multi-pass or cross-flow exchangers; designs with F under about 0.75 need more shells in series"?
A.LMTD correction factor F — multiplier below 1 applied to counter-current LMTD for multi-pass or cross-flow exchangers; designs with F under about 0.75 need more shells in series
B.LMTD correction factor F — extra thermal resistance (about 0.0002–0.0005 m²K/W for cooling water) added to the clean coefficient to allow for deposits over the run length
C.LMTD correction factor F — three-letter code for front head, shell and rear head types, for example AES meaning removable channel, single-pass shell and split-ring floating head
D.LMTD correction factor F — vapour velocity at which entrained liquid cannot flow down the column; trays are sized at about 80% of this limit using Fair or Souders-Brown correlations
A.extra thermal resistance (about 0.0002–0.0005 m²K/W for cooling water) added to the clean coefficient to allow for deposits over the run length
B.multiplier below 1 applied to counter-current LMTD for multi-pass or cross-flow exchangers; designs with F under about 0.75 need more shells in series
C.kettle gives a full theoretical stage and handles wide-boiling mixtures but costs more; thermosiphon relies on density-driven circulation with typically 10–25% vaporisation
D.three-letter code for front head, shell and rear head types, for example AES meaning removable channel, single-pass shell and split-ring floating head
8. Which term means: "extra thermal resistance (about 0.0002–0.0005 m²K/W for cooling water) added to the clean coefficient to allow for deposits over the run length"?
A.Fouling factor — three-letter code for front head, shell and rear head types, for example AES meaning removable channel, single-pass shell and split-ring floating head
B.Fouling factor — fixed tubesheet is cheapest but needs an expansion joint and cannot be shell-side cleaned; U-tube absorbs expansion but tube insides are hard to clean; floating head allows both
C.Fouling factor — tray malfunction at low vapour rate where liquid leaks through the perforations instead of crossing the weir, which sets the turndown limit
D.Fouling factor — extra thermal resistance (about 0.0002–0.0005 m²K/W for cooling water) added to the clean coefficient to allow for deposits over the run length
A.tray malfunction at low vapour rate where liquid leaks through the perforations instead of crossing the weir, which sets the turndown limit
B.vapour velocity at which entrained liquid cannot flow down the column; trays are sized at about 80% of this limit using Fair or Souders-Brown correlations
C.fixed tubesheet is cheapest but needs an expansion joint and cannot be shell-side cleaned; U-tube absorbs expansion but tube insides are hard to clean; floating head allows both
D.multiplier below 1 applied to counter-current LMTD for multi-pass or cross-flow exchangers; designs with F under about 0.75 need more shells in series
11. Which term means: "fixed tubesheet is cheapest but needs an expansion joint and cannot be shell-side cleaned; U-tube absorbs expansion but tube insides are hard to clean; floating head allows both"?
A.Fixed vs U-tube vs floating head — extra thermal resistance (about 0.0002–0.0005 m²K/W for cooling water) added to the clean coefficient to allow for deposits over the run length
B.Fixed vs U-tube vs floating head — vapour velocity at which entrained liquid cannot flow down the column; trays are sized at about 80% of this limit using Fair or Souders-Brown correlations
C.Fixed vs U-tube vs floating head — tray malfunction at low vapour rate where liquid leaks through the perforations instead of crossing the weir, which sets the turndown limit
D.Fixed vs U-tube vs floating head — fixed tubesheet is cheapest but needs an expansion joint and cannot be shell-side cleaned; U-tube absorbs expansion but tube insides are hard to clean; floating head allows both
A.three-letter code for front head, shell and rear head types, for example AES meaning removable channel, single-pass shell and split-ring floating head
B.trays suit high liquid rates, fouling and large diameters; structured packing gives lower pressure drop and higher capacity for vacuum and low-liquid-load services
C.vapour velocity at which entrained liquid cannot flow down the column; trays are sized at about 80% of this limit using Fair or Souders-Brown correlations
D.packed height equivalent to one theoretical plate, typically 0.3–0.6 m for structured packing; packed height equals stages required times this value
14. Which term means: "trays suit high liquid rates, fouling and large diameters; structured packing gives lower pressure drop and higher capacity for vacuum and low-liquid-load services"?
A.Tray vs packing — packed height equivalent to one theoretical plate, typically 0.3–0.6 m for structured packing; packed height equals stages required times this value
B.Tray vs packing — trays suit high liquid rates, fouling and large diameters; structured packing gives lower pressure drop and higher capacity for vacuum and low-liquid-load services
C.Tray vs packing — multiplier below 1 applied to counter-current LMTD for multi-pass or cross-flow exchangers; designs with F under about 0.75 need more shells in series
D.Tray vs packing — extra thermal resistance (about 0.0002–0.0005 m²K/W for cooling water) added to the clean coefficient to allow for deposits over the run length
A.packed height equivalent to one theoretical plate, typically 0.3–0.6 m for structured packing; packed height equals stages required times this value
B.trays suit high liquid rates, fouling and large diameters; structured packing gives lower pressure drop and higher capacity for vacuum and low-liquid-load services
C.three-letter code for front head, shell and rear head types, for example AES meaning removable channel, single-pass shell and split-ring floating head
D.vapour velocity at which entrained liquid cannot flow down the column; trays are sized at about 80% of this limit using Fair or Souders-Brown correlations
17. Which term means: "packed height equivalent to one theoretical plate, typically 0.3–0.6 m for structured packing; packed height equals stages required times this value"?
A.HETP — fixed tubesheet is cheapest but needs an expansion joint and cannot be shell-side cleaned; U-tube absorbs expansion but tube insides are hard to clean; floating head allows both
B.HETP — kettle gives a full theoretical stage and handles wide-boiling mixtures but costs more; thermosiphon relies on density-driven circulation with typically 10–25% vaporisation
C.HETP — multiplier below 1 applied to counter-current LMTD for multi-pass or cross-flow exchangers; designs with F under about 0.75 need more shells in series
D.HETP — packed height equivalent to one theoretical plate, typically 0.3–0.6 m for structured packing; packed height equals stages required times this value
A.vapour velocity at which entrained liquid cannot flow down the column; trays are sized at about 80% of this limit using Fair or Souders-Brown correlations
B.extra thermal resistance (about 0.0002–0.0005 m²K/W for cooling water) added to the clean coefficient to allow for deposits over the run length
C.tray malfunction at low vapour rate where liquid leaks through the perforations instead of crossing the weir, which sets the turndown limit
D.packed height equivalent to one theoretical plate, typically 0.3–0.6 m for structured packing; packed height equals stages required times this value
20. Which term means: "tray malfunction at low vapour rate where liquid leaks through the perforations instead of crossing the weir, which sets the turndown limit"?
A.Weeping and dumping — multiplier below 1 applied to counter-current LMTD for multi-pass or cross-flow exchangers; designs with F under about 0.75 need more shells in series
B.Weeping and dumping — tray malfunction at low vapour rate where liquid leaks through the perforations instead of crossing the weir, which sets the turndown limit
C.Weeping and dumping — fixed tubesheet is cheapest but needs an expansion joint and cannot be shell-side cleaned; U-tube absorbs expansion but tube insides are hard to clean; floating head allows both
D.Weeping and dumping — three-letter code for front head, shell and rear head types, for example AES meaning removable channel, single-pass shell and split-ring floating head
A.fixed tubesheet is cheapest but needs an expansion joint and cannot be shell-side cleaned; U-tube absorbs expansion but tube insides are hard to clean; floating head allows both
B.vapour velocity at which entrained liquid cannot flow down the column; trays are sized at about 80% of this limit using Fair or Souders-Brown correlations
C.three-letter code for front head, shell and rear head types, for example AES meaning removable channel, single-pass shell and split-ring floating head
D.packed height equivalent to one theoretical plate, typically 0.3–0.6 m for structured packing; packed height equals stages required times this value
23. Which term means: "vapour velocity at which entrained liquid cannot flow down the column; trays are sized at about 80% of this limit using Fair or Souders-Brown correlations"?
A.Jet flooding — tray malfunction at low vapour rate where liquid leaks through the perforations instead of crossing the weir, which sets the turndown limit
B.Jet flooding — multiplier below 1 applied to counter-current LMTD for multi-pass or cross-flow exchangers; designs with F under about 0.75 need more shells in series
C.Jet flooding — kettle gives a full theoretical stage and handles wide-boiling mixtures but costs more; thermosiphon relies on density-driven circulation with typically 10–25% vaporisation
D.Jet flooding — vapour velocity at which entrained liquid cannot flow down the column; trays are sized at about 80% of this limit using Fair or Souders-Brown correlations
A.kettle gives a full theoretical stage and handles wide-boiling mixtures but costs more; thermosiphon relies on density-driven circulation with typically 10–25% vaporisation
B.vapour velocity at which entrained liquid cannot flow down the column; trays are sized at about 80% of this limit using Fair or Souders-Brown correlations
C.packed height equivalent to one theoretical plate, typically 0.3–0.6 m for structured packing; packed height equals stages required times this value
D.tray malfunction at low vapour rate where liquid leaks through the perforations instead of crossing the weir, which sets the turndown limit
26. Which term means: "kettle gives a full theoretical stage and handles wide-boiling mixtures but costs more; thermosiphon relies on density-driven circulation with typically 10–25% vaporisation"?
A.Kettle vs thermosiphon reboiler — extra thermal resistance (about 0.0002–0.0005 m²K/W for cooling water) added to the clean coefficient to allow for deposits over the run length
B.Kettle vs thermosiphon reboiler — tray malfunction at low vapour rate where liquid leaks through the perforations instead of crossing the weir, which sets the turndown limit
C.Kettle vs thermosiphon reboiler — kettle gives a full theoretical stage and handles wide-boiling mixtures but costs more; thermosiphon relies on density-driven circulation with typically 10–25% vaporisation
D.Kettle vs thermosiphon reboiler — three-letter code for front head, shell and rear head types, for example AES meaning removable channel, single-pass shell and split-ring floating head
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