3rd Class Power Engineering - B1 - Questions and Answers
Question 1
High Temperature Plastic insulation?
Correct Answer
- Comes in a mouldable cement form and is used to fill gaps in refractory/block insulation
- Temperature limit of 1050 deg.C
Question 2
Code Requirements for Pressure Gauges?
Correct Answer
- Every boiler must have a pressure gauge attached to the steam space, water column, or steam connection
- Gauges must be fitted with a shut off valve or cock
- Gauges should contain siphons to prevent steam from entering the gauge
- Each boiler shall be provided with a connection of at least NPS 1/4 (6mm) pipe size so an inspector can connect his test
gauge for the accuracy of the boilers gauge
- The gauge must be capable of measuring no less than 1.5 times the pressure at which the boiler safety valve has set
Page 1 of 137
,Question 3
Method of support for Furnace Walls?
Correct Answer
- Tubes are welded into the top headers
- Buckstays are used to give furnace walls lateral support
Question 4
Plate thickness range for drums and shells?
Correct Answer
6.4 mm to 250 mm
Question 5
Gas Bypass Systems?
Correct Answer
- Separates the convection section in the furnace into 2 or more parallel gas passes, with control dampers installed for
each pass
- At full load, each set of louvres to each pass is open 100%
- Spray desuperheating is usually used up to about 40% of full load
- At lower loads, more gas os passed through the reheat section and less through the superheat section, which allows the
reheat temperature to remain constant
Page 2 of 137
,Question 6
Multiple Retort Underfeed Stoker Furnaces?
Correct Answer
- Several retorts which are inclined from the front of the furnace toward the rear of the furnace
- Each retort is supplied with coal by a ram and the coal moves along the inclined retorts to the rear of the furnace where
the ash is discharged
Question 7
2 thing to check in preparation to Drying out Refractory?
Correct Answer
- Ensure that the low water level shutdown is ON and make sure the drum vent is open when filling
- Ensure the gauge glass is in service
Question 8
Axial Staged Return Flow, Low NOx burner?
Correct Answer
- Combustion air is fed in several stages which separates the primary and secondary air to slow combustion
- Recycles flue gas back to the burner outlet
Page 3 of 137
, Question 9
The ASME and ASTM entail what rules around boiler tubing?
Correct Answer
- All pressure tubes are subjected to a hydrostatic test or NDT testing after manufacture
- Maximum tube size in boilers cannot exceed 127 mm
Question 10
How does the operating pressure of the boiler affect Natural Circulation?
Correct Answer
- As boiler pressure increases, the density of steam increases
- The higher the pressure, the less difference in density there is between downcomer water and riser water/steam
mixture, this DECREASES circulation
- Natural Circulation boilers are limited to pressures below 21 000 kPa
Question 11
Sootblowing around Reheaters?
Correct Answer
- Blowing soot around the wall tubes of a reheater will decrease reheat temperature
- Blowing the reheater tubes themselves will increase reheat temperature
Page 4 of 137
Question 1
High Temperature Plastic insulation?
Correct Answer
- Comes in a mouldable cement form and is used to fill gaps in refractory/block insulation
- Temperature limit of 1050 deg.C
Question 2
Code Requirements for Pressure Gauges?
Correct Answer
- Every boiler must have a pressure gauge attached to the steam space, water column, or steam connection
- Gauges must be fitted with a shut off valve or cock
- Gauges should contain siphons to prevent steam from entering the gauge
- Each boiler shall be provided with a connection of at least NPS 1/4 (6mm) pipe size so an inspector can connect his test
gauge for the accuracy of the boilers gauge
- The gauge must be capable of measuring no less than 1.5 times the pressure at which the boiler safety valve has set
Page 1 of 137
,Question 3
Method of support for Furnace Walls?
Correct Answer
- Tubes are welded into the top headers
- Buckstays are used to give furnace walls lateral support
Question 4
Plate thickness range for drums and shells?
Correct Answer
6.4 mm to 250 mm
Question 5
Gas Bypass Systems?
Correct Answer
- Separates the convection section in the furnace into 2 or more parallel gas passes, with control dampers installed for
each pass
- At full load, each set of louvres to each pass is open 100%
- Spray desuperheating is usually used up to about 40% of full load
- At lower loads, more gas os passed through the reheat section and less through the superheat section, which allows the
reheat temperature to remain constant
Page 2 of 137
,Question 6
Multiple Retort Underfeed Stoker Furnaces?
Correct Answer
- Several retorts which are inclined from the front of the furnace toward the rear of the furnace
- Each retort is supplied with coal by a ram and the coal moves along the inclined retorts to the rear of the furnace where
the ash is discharged
Question 7
2 thing to check in preparation to Drying out Refractory?
Correct Answer
- Ensure that the low water level shutdown is ON and make sure the drum vent is open when filling
- Ensure the gauge glass is in service
Question 8
Axial Staged Return Flow, Low NOx burner?
Correct Answer
- Combustion air is fed in several stages which separates the primary and secondary air to slow combustion
- Recycles flue gas back to the burner outlet
Page 3 of 137
, Question 9
The ASME and ASTM entail what rules around boiler tubing?
Correct Answer
- All pressure tubes are subjected to a hydrostatic test or NDT testing after manufacture
- Maximum tube size in boilers cannot exceed 127 mm
Question 10
How does the operating pressure of the boiler affect Natural Circulation?
Correct Answer
- As boiler pressure increases, the density of steam increases
- The higher the pressure, the less difference in density there is between downcomer water and riser water/steam
mixture, this DECREASES circulation
- Natural Circulation boilers are limited to pressures below 21 000 kPa
Question 11
Sootblowing around Reheaters?
Correct Answer
- Blowing soot around the wall tubes of a reheater will decrease reheat temperature
- Blowing the reheater tubes themselves will increase reheat temperature
Page 4 of 137
