- Packaged watertube boilers capacities range from?
A) 2300 kg - 65000 kg per hour
B) 500 kg - 100 mg per hour
C) 15 psi - 15000 kg per hour
D) 65000 - 100000 kg per hour
A) 2300 kg - 65000 kg per hour
- The main advantage of the packaged Boiler is its _____ _____.
A) small size
B) compact design
C) low cost
D) quality steam
C) low cost
- Field erected boilers have outputs of?
A) 75000 kg/hr
B) 100000 kg/hr
C) 100 mg/hr
D) 150000 kg/hr or more
D) 150000 kg/hr or more
- One square meter of heating surface equals 10 kilowatts. The heating surface of a Boiler must be determined by computing the area of the surface involved in square meters and where a computation is to be made of a curved surface; the surface having the greater radius shall be taken.
A) true
B) false
A) true
- Where electric power is used as the heating source, the Boiler rating shall be the maximum kilowatt rating of the _____ _____.
A) power plant
B) heating element
C) boiler wiring
D) MCC
B) heating element
- Where the Boiler provides the entire steam supply to an electric generating unit, the output of the Boiler is expressed in terms of power output of the generator (for example a 300 megawatt Boiler).
A) true
B) fals
A) true
- The downcomers are located in the _____ regions of the Boiler, or external to the furnace altogether. The risers are located in the _____ zones of the Boiler, being exposed to radiant heat of the furnace or to the very hot flue gases near the furnace.
A) back, front
B) cooler, hottest
C) water, furnace
D) drum, radiant
B) cooler, hottest
- Most downcomers run horizontally between the steam drum and the mud drum.
A) true
B) false
B) false
- The steam separating equipment separates the _____ from the steam/water mixture.
A) water
B) steam
C) impurities
D) water droplets
B) steam
- There are several factors that influence the natural circulation in a watertube Boiler. These are:
A) the height of the steam drum above the bottom drum or header
B) the amount of heat applied to the tube. The hotter the tube becomes, the more steam bubbles are formed, creating more mass differential and thus more circulation
C) the operating pressure of the Boiler. As Boiler pressures increase, the density of the steam increases
D) the cleanliness of the tubes can also affect circulation
E) all of the above
E) all of the above
- The purpose of the downcomers is to supply:
A) hot water to the steam drum B) cool water to the steam drum C) cool water from steam drum to rest of Boiler D) steam to steam drum E) Boiler feedwater to the Boiler
C) cool water from steam drum to rest of Boiler
- These types of boilers (A,D, and O) have furnaces cooled by _____ lining the furnace walls.
A) watertubes
B) fans
C) desuperheaters
D) air circulation
A) watertubes
- In the A,D, and O type Boiler steam bubbles form in the hottest tubes and rise to the steam drum, where the steam is separated out of the water and steam mixture. Circulation is maintained by water returning to the mud drum through the cooler tubes. The hotter tubes, risers, are the ones in the radiant area of the furnace and the hottest areas of the generating bank of tubes.
A) true
B) false
A) true
- A steam generating unit consists of a number of elements all of which contribute to the production of steam. The elements of a typical steam generator include:
1) Boiler
2) superheater
3) ash removal equipment
4) reheated
5) economizer
6) steam piping
7) air heater
8) fuel equipment
9) draft fans
A) 1,2,7,8,9
B) 1,2,4,5,7,8,9
C) 3,4,6,7,8
D) 1,2,3,4,5,7,8,9
D) 1,2,3,4,5,7,8,9
- In steam generating units the feedwater entering the Boiler section first passes through the _____ section where it is heated by the combustion gases leaving the Boiler
A) furnace
B) economizer
C) Boiler drum
D) superheater
B) economizer
- Combustion air for the burners is preheated to _____ in the air heater section by combustion gases leaving the economizer section
A) 150 C
B) 100 C
C) 350 C
D) 500 C
C) 350 C
- Generally two types of draft fans are used. A _____ _____ fan supplies air to the air preheater. The preheated air (350 C) for combustion goes to the coal pulverized and to the burners. An _____ _____ fan exhausts the combustion gases (170 C) from the air heater to the stack
A) centre mounted, external mounted
B) forced draft, induced draft
C) induced draft, forced draft
D) turbine draft, ejection draft
B) forced draft, induced draft
- Natural circulation in a Boiler depends upon the _____ in the density of a column of water and the density of a column containing a steam/water mixture
A) amount
B) mass
C) difference
D) density
C) difference
- The difference in density between water and saturated steam becomes progressively less with increased pressure and disappears altogether at the critical pressure _____.
A) 22106 kPa
B) 15000 kPa
C) 10000 kPa
D) 25000 kPa
A) 22106 kPa
- Steam generators operating above critical pressure are said to be _____ critical and steam generators operating below critical are classed as _____ critical.
A) sub, super
B) super, sub
C) normal, pre
D) high, low
B) super, sub
- The advantage of forced circulation in a Boiler is a _____ flow in all tubes.
A) negative
B) greater
C) positive
D) mass
C) positive
- The disadvantages of forced circulation in a Boiler are the _____ _____ of equipment, pumps, piping, etc.
A) greater use
B) increased costs
C) higher maintenance
D) numbers of
B) increased costs
- The main feature of a controlled circulation Boiler is a (circulating) pump, which is used to provide circulation.
A) true
B) false
A) true
- Not all once through boilers use forced circulation.
A) true
B) false
B) false
