4A Unit 12 Questions and Answers Graded A+

4A Unit 12 Questions and Answers Graded A+ (4-063-1.14) The operator, while blowing off a boiler, should have an assistant to: Select one: a. Open the blow-off tank drain b. Watch the gauge glass level c. Close the quick opening valve in a hurry d. Open the slow opening valve b. Watch the gauge glass level (4-091-3.3) In a mechanical atomizing burner with three fixed capacity burners, the Intermediate and high fire burner nozzles may have higher capacities than the primary burner nozzle: Select one: a. To allow slower boiler warm-ups b. Because of the pump being of the positive displacement type c. To prevent pressure surges d. To give greater firing variations a. To allow slower boiler warm-ups (4A-30-12-01-02-03) Which of these groups is the combustible components of coal. Select one: a. Nitrogen, oxygen, ash b. Carbon, hydrogen, sulphur c. Carbon dioxide, nitrogen, sulphur dioxide d. Carbon, ash, nitrogen b. Carbon, hydrogen, sulphur (4-087-5.2) A sudden drop in steam pressure causes: Select one: a. "shrinkage" b. a single element feedwater control to immediately add water to the drum c. a sudden increase in drum level d. a rapid collapse of steam bubbles in the boiler c. a sudden increase in drum level (4-062-1.1) Stationary soot blowers are installed in the: Select one: a. Convection zones b. Secondary superheater bank c. Primary superheater bank d. Reheater bank a. Convection zones (4-058-2.8) The efficiency of a combined cycle plant, using a pressurized fluidized bed boiler, is about _____ higher than that of a conventional pulverized coal plant. Select one: a. 5% b. 10% c. 15% d. 20% a. 5% (4-091-3.2) Maximum static pressure in a fuel oil line before the oil pump is limited by code to approximately: Select one: a. 35 kPa b. 70 kPa c. 10 kPa d. 15 kPa a. 35 kPa (4-058-3.2) Fluidized bed plants can be built smaller than other designs because of: Select one: