This set of Pulp and Paper Problems focuses on “Liquor Evaporation”.
1. What is the full form of M.E.E?
a) Multiple-effect evaporators
b) Molecular-energy evaporators
c) Multiple –entropy evaporators
d) Molecular-engineering evaporators
View Answer
Explanation: Multiple-effective evaporators are a series of series of 4 to 8 evaporators with indirect heating used for removing water from the dilute black liquor coming from the pulp washers.
2. If 100lb of black liquor containing 15lb of solids and 85lb of water is evaporated to 30lb; with a stream economy of 5 it would take 14lb of steam to remove the 70lb of water. The steam economy is about 0.8 per effect. An overall steam economy of the system is ?
a) 9-10
b) 4-5
c) 20-25
d) 16-17
View Answer
Explanation: An overall steam economy of 4-5, depending on the number of effects, is normally good for mill operation. Stream economy just equals to the water mass evaporated by the mass of stream used.
3. Stream economy equals water mass evaporated by the mass of stream used.
a) True
b) False
View Answer
Explanation: Stream economy just equals water mass evaporated by the mass of stream used. The subsequent condensates are contaminated with volatile black liquor components and are usually allowed to the sewer.
4. What is the full form of L.T.V?
a) Long tube vertical
b) Less tube vertical
c) Leakage tube vent
d) Lombarda tube vent
View Answer
Explanation: Long tube vertical bodies. Each effect consists of a long tube vertical evaporator.
5. Falling film evaporators are used in conventional evaporators except for the mechanism for evaporation in each stage is of different unit.
a) True
b) False
View Answer
Explanation: Falling film evaporators are used in conventional evaporators except for the mechanism for evaporation in each stage is of different unit.
6. About 65% of the methanol and BOD is concentrated in 6% of the entire condensate stream in the upper portion of the plates just to release __________
a) Four condensate segregation
b) Fine copper segregation
c) Foul condensate segregation
d) Free condensate segregation
View Answer
Explanation: About 65% of the methanol and B.O.D. is concentrated in 6% of entire condensate stream in the upper portion of the plates just to release foul condensate segregation. The remaining condensate is collected back from the overall portion of the plates which is suitable for brown stock washing.
7. Tall oil is a by-product mixture of the saponified fatty acids, resin acids and unsaponifiables which are derived from the wood extractives of ___________
a) Hardwood
b) Softwood
c) Turpentine
d) Lignin
View Answer
Explanation: Tall oil is a by-product mixture of saponified fatty acids, resin acids and unsaponifiables which are derived from the wood extractives of softwoods.
8. ___________ is a mixture of volatile extractives collected during digester heating.
a) Kraft lignin
b) Tall oil
c) Wax
d) Turpentine
View Answer
Explanation: Turpentine is a mixture of volatile extractives collected during digester heating. It’s collected from the digester relief gases and solids for solvents and limited dis-infectants which are used in household pine oil cleaners.
9. ___________ is recovered by acidification and used dispersants, phenol-formaldehyde adhesive extenders, and binders in printing inks.
a) White liquor
b) Brown liquor
c) Black liquor
d) Green liquor
View Answer
Explanation: Black liquor is recovered by acidification and used dispersants, phenol-formaldehyde adhesive extenders, and binders for printing inks.
10. Indirect concentrators are forced circulation used to concentrate black liquor for the range where burkeite precipitates as scale. Where are they used?
a) Low-odour recovery boilers
b) High-odour recovery boilers
c) Constant-odour recovery boiler
d) Burst-odour recovery boiler
View Answer
Explanation: Indirect concentrators are forced circulation used to concentrate black liquor for the range where burkeite precipitates as scale. They are used in low-odour boilers.
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