Which of the following are True? 1. Kettle reboilers have a large liquid volume 2. Kettle reboilers may use a weir to keep fluid above the tubes 3. It is important not to flood Thermosyphon reboilers. 4. Thermosyphons depend on a difference in fluid density to promote flow.
1,2,3
1,2,4
1,3,4
2,3,4
1,2,3,4
In a Cooling tower the drift eliminators:
Break the water into thin sheets to increase the surface area
Discharge the air at high velocity to minimize re-circulation
Induce the flow of air through the cooling section
Separate entrained moisture from the air
Prevent waves in the reservoir
Which of the following are true for plate heat exchangers? 1. High turbulence helps prevent fouling 2. Heat transfers well through the thin plates 3. Not good for thick fluids 4. They have a low-pressure drop 5. Gasket placement is critical
2,3,4,5
1,3,4,5
1,2,4,5
1,2,3,5
Which of the following are true for feed water heaters? 1. High pressure feedwater heaters are used between the BFP and boiler 2. Low pressure feedwater heaters are used between the hotwell and dearator 3. Turbine extraction steam is commonly used for feedwater heater 4. Feedwater heaters increase cycle efficiency, resulting in lower fuel costs 5. Feed water heaters are not considered pressure vessels
1,2
1,3
1,4
Hairpin exchangers:
Are mainly used when the exchange surface are exceeds 50 m
Are easily assembled
Are easily cleaned
Are used only for low pressures
Are rarely used for heat exchange surfaces below 18m2
In one design of shell and tube exchanger, a floating head:
Helps to allow for expansion due to heat
Helps the operator to control water hammer
Helps the millwright to flare the tubes
Can be constructed of plastic
Concentric pipe heat exchangers
Typically use concurrent flows
Always use a smooth bore annulus
Are bulky
Always use consecutive flows
Are used for low heat duties
Which of the following are true for overhead aerial condensers? 1. The footprint influences the design choice 2. Air re-circulation is a way to control temperatures in a tube bank 3. Headers or header boxes contain plugs for tube cleaning 4. Freezing of tube bundles is not normally a concern even on cold days 5. The vertical type is only used for steam condensing
3,4,5
1,3,5
1,2,3,4,5
The hyperbolic cooling tower has the advantages of: 1. Low initial cost 2. Low power consumption 3. Dependability 4. Minimum maintenance
Which of the following are true for aerial heat exchangers? 1. A bay may have on or more tube bundles 2. A unit may have one or more bays 3. A bank may have on or more units 4. Temperature control may be attained by stop start or variable speed fans. 5. Cleaning the outside of coils is a regular maintenance chore.
2,3
2,4,5
