Chapters 10-13 Flashcards
Buildup of material on the internal surfaces of heat exchangers.
Fouling
What types of heat transfer does a heat exchanger use?
Conduction and Convection
What is evidence of fouling on a heat exchanger? A. Increase dP B. Reduce heat transfer C. Reduces flow D. All above
D. All above
Floating head heat exchanger allows for ____ expansion.
thermal
_____ cooling towers use evaporative cooling, moving heat from the water to the air.
A. Dry
B. Wet
B. Wet
The air temperature as measured by a thermometer that takes into account the relative humidity.
Wet Bulb Temperature
Temperature difference between water leaving the tower and wet bulb temperature.
Approach to Tower
Water treatment systems are designed to control: A. Scale on exchanger tubes B. Algae on the wet deck C. Wood decay D. All above
D. All above
(T/F) Cooling towers are only single-celled.
FALSE. They can be single or multi-celled.
(T/F) Cooling tower pH should be kept between 7.8 and 8.4 (slightly basic)
True
Cooling Tower water should be sampled at least once per shift for:
A. dissolved solids (causes scaling)
B. dissolved gases (cause basin to be acidic)
C. microorganisms (ct’s are a good breeding ground)
D. All above
D. All above
A _____ is a steam generation system.
boiler
What is the most common type of boiler in our industry?
A. Water tube
B. Fire Tube
A. Water Tube
(T/F) Circulation is achieved through the difference in the density of hot and cool water.
True
Fire brick or castable material that surrounds boilers.
Refractory
What types of heat transfer do steam generators/boilers use?
Conduction, Convection, Radiation
Used to preheat boiler feed water (BFW) in a boiler.
Economizer
Designed to insulate and reduce heat loss, and to reflect radiant heat back into the firebox.
Refractory
Steam that is heated to a higher temperature than the boiling point at the control pressure.
Superheated steam
A steam drum includes: A. a water/steam interface B. BFW inlet C. Blowdown header D. All above
D. All above
One cubic foot of water will occupy _____ cubic feet when converted to steam at atmospheric pressure.
1,600
Thing put into a natural gas supply to make you aware of a gas leak.
Odorant
Device that strips out dissolved oxygen. A. Stripper B. Deaerator C. Plenum D. Downcomer
B. Deaerator
Sloping section of a furnace that has transitions between radiant and convective section. A. Bridgewall Section B. Convection Section C. Shock Bank D. Stack
A. Bridgewall section
Top of the furnace A. Bridgewall Section B. Convection Section C. Shock Bank D. Stack
B. Convection Section
First bank of tubes above radiant section in furnace. A. Bridgewall Section B. Convection Section C. Shock Bank D. Stack
C. Shock Bank
Where the combustion gases in a furnace go out. A. Bridgewall Section B. Convection Section C. Shock Bank D. Stack
D. Stack
Radiant heat account for \_\_\_ % of heat transfer in a furnace. A. 50-60 B. 60-70 C. 70-80 D. 80-90
B. 60-70
Most common type of furnace in industry.
Cabin Furnace
Complete combustion produces two chemicals. What are they?
CO2 and H2O
The single most important variable affecting efficiency in a furnace.
Controlling excess oxygen
In a boiler, if the control logic detects that the flame is out, what happens to the fuel?
It is shut off
Part of furnace that contains the burner and open flames.
Firebox
Direct contact of the flame with furnace tubes.
Flame Impingement
