4.12 Heat Exchangers and Cooling Towers

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.

In a Cooling tower the drift eliminators:

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

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

Hairpin exchangers:

In one design of shell and tube exchanger, a floating head:

Concentric pipe heat exchangers

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

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.