This set of Energy Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Soot Blowers”.
1. The method of removing soot from the power plant machineries is known as _________
a) Soot cleansing
c) Soot blowing
Explanation: The products of combustion cling to the water tubes, economizer tubes, air preheater tubes and super heater tubes. This lowers the efficiency of the plant by reducing heat transfer. So, regular removal of soot or dust is necessary this method is known as soot blowing.
2. Why nozzle tubes are provided in the soot blowers?
a) To moistures the dust
b) To admit high pressure steam
c) To blow away the soot
d) To suck in the dust and exhaust it at high pressure
Explanation: The usual form for the smaller boilers is a dead-end tube projecting through the setting and extending into the tube banks. A number of small lateral nozzles are provided and the external head is arranged so that high pressure steam can be admitted to the tube and at the same time the tube is rotated around its axis.
3. Which type of blower advances into the furnace, cleans and comes back?
a) Wall blower
b) Retractable blower
c) Air heat blower
d) Insert able kinetic blower
Explanation: Soot blower consists of a set of tubes fitted with nozzles carrying high velocity jet of steam or air. In the hotter parts of the boiler, the blower advances into the furnace, cleans the heat transfer surfaces and comes back. This type of soot blower is known as retractable soot blower.
4. Why are there number soot blower units in large blower?
a) To obtain high efficiency
b) To clean the boiler in short amount of time
c) To clean adequately
d) For easy replacement
Explanation: Steam jets clean soot from heating surface in their proximity, but the action is limited in extent in a close array such as tube banks; hence several units may be needed to clean the boiler adequately. It is quite common to see 8 to 16 units in a large boiler.
5. Why operating heads of soot blowers are automated?
a) Because they are tedious to operate manually
b) Because they cannot be handled at once
c) Because they are positioned at different parts of machine
d) Because it is quicker by automation
Explanation: Soot blowers are tedious to operate manually, and since must not all be operated simultaneously, the operating heads are electric motor powered and operated by remote control on an automatic sequential basis.
6. Why on some boilers the draft system controls have to be positioned abnormally in soot blowers?
a) To avoid the soot being blown back into boiler
b) To get a good grip for blowing out the soot from the boiler
c) due to lack of space in the boiler
d) To avoid the heat of boiler affecting the soot blowers
Explanation: On some boilers the automatic draft system controls have to be positioned for abnormally high draft before beginning the soot blowing operation; otherwise the release of stem into the setting may blow soot and smoke into the boiler room.
7. In which state would be the soot blower when it’s not in use?
a) Dry and cooled
b) Dry and uncooled
c) Wet and cooled
d) Dry and hot
Explanation: When not in use the soot blower tube of the system would be dry and uncooled, and subject to gas temperatures. Even with alloy tubes the deterioration is relatively rapid on units normally experiencing high gas temperatures.
8. What is the advantage of using retractable soot blower?
a) Has high blowing capacity compared to steam and wall blowers
b) Protects from high temperatures when not in use
c) Consumes less amount of electricity
d) Produces less amount of noise
Explanation: Retractable blower, though more expensive initially, have the advantage of protection from high temperature when not in use. Also, using only two travelling nozzles, the jet can be larger without excessive steam drain, and the projected blast distance is greater.
9. Why is it necessary to observe temperature drops in the soot blower?
a) To avoid net loss
b) To avoid the soot getting struck in soot blower
c) To avoid over usage
d) To avoid overconsumption of electricity
Explanation: It is necessary to observe temperature drops routinely. Obviously if the temperature drops 24°C after blowing, the interval might well be decreased, where as if 12°C were observed; it could represent a net loss because the value of the steam used was more than that of the increment of flue gas heat.
10. Is there a chance of fire due to the accumulation soot inside the boiler.
Explanation: A soot fire can be damaging to a boiler because it can cause localized hotspots to occur in the tubes. These hotspots may reach temperatures that weaken the materials of the tubes. Soot blowers reduce the risk of soot fires and their resulting damage.
Sanfoundry Global Education & Learning Series – Energy Engineering.
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