Air ejectors and DC heaters Exam Questions And Answers Verified 100% Correct

Air ejectors and DC heaters Exam Questions And Answers Verified 100% Correct Condensate is pumped from the condenser to the DC heater instead of directly to the boiler because __________. a. boiler feed pumps must operate with a negative suction head b. suspended solids in the condensate must be eliminated c. condensate should be deaerated before entering the boiler d. condensate at condensing temperature is too hot and will cause thermal stress in the boiler - ANSWER C Which of the DC heater operations listed will result in excessive dissolved oxygen in boiler water? a. Excessively high water level in the heater. b. Adding excessive make up feed. c. Operating the heater with a closed air vent. d. All of the above. - ANSWER D Under normal conditions, steam to the DC heater is supplied directly from which of the systems listed? a. Main steam b. 600 psi auxiliary steam c. 150 psi auxiliary steam d. Auxiliary exhaust steam - ANSWER D Discharging an excessive amount of cold water into the DC heater during normal steaming conditions could cause __________. a. flashing at the feed pump suction b. excess oxygen in the feed water c. water hammer in the economizer d. increased back pressure - ANSWER B The DC heater functions to __________. a. remove air from feed water b. heat feed water c. store feed water d. all of the above - ANSWER D In a closed feed water system, the greatest deaeration of condensate occurs in the __________. a. DC heater b. atmospheric drain tank c. air ejector condenser d. vent condenser - ANSWER A The purpose of the steam control valves installed in the auxiliary exhaust line is to __________. a. control steam admission and maintain the proper steam spray pattern in the DC heater b. regulate back pressure in the desuperheater line c. preheat the condensate before it enters the vent condenser d. seal the vent condenser to prevent the escape of condensate - ANSWER A The minimum design height of the DC heater is determined by the _______. a. dew point temperature of the stack gases b. minimum net positive suction head required by the main feed pump c. maximum condensate pump discharge pressure d. desuperheater outlet temperature - ANSWER B Why is it necessary to have a relief valve protect the deaerating feed tank from internal pressure? a. Because the tank receives auxiliary exhaust. b. Because the tank receives high pressure drains. c. Because the tank receives large amounts of water. d. Because the tank drains to the main condenser. - ANSWER B During cold ship start-up, you should open the feed water outlet and condensate valves to a DC heater in order to __________. a. avoid running the feed pump 'dry' b. expel non-condensable vapors from the vent c. thoroughly atomize incoming condensate d. prevent excessive pressure - ANSWER A The DC heater automatic level dump valve is used to __________. a. divert the flow of condensate from the first stage heater to the vent condenser b. maintain a proper condensate level in the condenser hot well c. recirculate condensate to the atmospheric drain tank d. drain excess feed water to the distilled water tank - ANSWER D Which of the conditions listed may be indicated by the lifting of the DC heater relief valve? a. A malfunctioning auxiliary exhaust make-up steam regulating valve. b. Excessive deaeration of the feed water. c. Low back pressure in the auxiliary exhaust line. d. Low water level continually maintained in the DC heater. - ANSWER A Improper boiler feed water deaeration could be directly linked to __________. a. operating with excessive condensate depression b. fluctuating deaerating feed tank level as a result of taking on makeup feed too rapidly c. fluctuating condensate pressure due to not maintaining proper hot well level d. all of the above - ANSWER D Which of the components listed prevents water from flowing back into the auxiliary exhaust line if the deaerating feed tank becomes flooded? a. Exhaust piping b. Pumps c. Check valve d. Reverse-acting relief valve - ANSWER C To provide emergency feed water supply to a steaming boiler, if it becomes necessary to secure the DC heater, suction should be taken on the distilled water tank using the __________. a. emergency injector discharge b. emergency feed pump c. feed booster pump d. main condensate pump - ANSWER B If the boiler water level is normal, the main condenser hot well level is normal, and the DC heater level is 40% full, you should __________. a. prime the condensate pump b. bypass the vent condenser c. slow the main unit d. open the makeup feed vacuum drag line - ANSWER D In a DC heater, which source of steam is commonly used to heat and deaerate condensate? a. Root steam b. Auxiliary exhaust steam c. Main steam d. Auxiliary steam - ANSWER B