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Steam Control Valve and Deaerating Feed Heater Operations, Exams of Nursing

Detailed information on the operation and maintenance of steam control valves and deaerating feed heaters in a steam power plant. It covers topics such as the factors affecting steam flow rate, the purpose and function of various components like relief valves, level control systems, and air ejectors. The document also discusses common issues and troubleshooting procedures related to the deaerating feed heater system. The comprehensive coverage of these critical systems in a steam power plant makes this document a valuable resource for students and professionals in the field of power engineering, mechanical engineering, and thermal systems.

Typology: Exams

2024/2025

Available from 10/06/2024

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Air Ejectors and DC Heaters Exam
Questions and Answers 2025.
With the steam control valve wide open during normal operation, the rate of
steam flow from the auxiliary exhaust steam line to the DC heater is
actually a function of
.
a. rate of condensation in the DC heater
b. spring pressure of the spray valves
c. water level in the DC heater reservoir
d. rate of evaporation in the DC heater - Answer A
In order to test the lifting pressure of the deaerating feed heater relief valve,
you would
.
I. close the auxiliary exhaust dump valve to the main and auxiliary
condensers
II. increase the set point of the make-up steam regulator to the auxiliary
exhaust system
a. I only
b. II only
c. Both I and II
d. Neither I nor II - Answer C
The DC Heater functions to .
e. store, heat, and deaerate feed water
f. chemically treat feed water to remove carbonic gas
g.ensure recirculation in the feed water system
h.remove the major amount of non-condensable gases from the main
condenser - Answer A
If the DC heater relief valve lifts frequently, the cause can be excessive
.
i. condensate supplied to the DC heater
j. auxiliary exhaust steam pressure
k. feed water recirculated from the feed pump
l. makeup feed introduced to the system - Answer B
If the boiler water and condenser hot well levels are normal, but the DC
heater level is only 30% of full, you should .
m.increase the speed of the condensate pump
n. open the feed pump recirculating valve wide
o. open the makeup feed
p. bypass the vent condenser and third-stage feed heater - Answer C
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Air Ejectors and DC Heaters Exam

Questions and Answers 2025.

With the steam control valve wide open during normal operation, the rate of steam flow from the auxiliary exhaust steam line to the DC heater is actually a function of . a. rate of condensation in the DC heater b. spring pressure of the spray valves c. water level in the DC heater reservoir d. rate of evaporation in the DC heater - Answer A In order to test the lifting pressure of the deaerating feed heater relief valve, you would . I. close the auxiliary exhaust dump valve to the main and auxiliary condensers II. increase the set point of the make-up steam regulator to the auxiliary exhaust system a. I only b. II only c. Both I and II d. Neither I nor II - Answer C The DC Heater functions to. e. store, heat, and deaerate feed water f. chemically treat feed water to remove carbonic gas g. ensure recirculation in the feed water system h.remove the major amount of non-condensable gases from the main condenser - Answer A If the DC heater relief valve lifts frequently, the cause can be excessive . i. condensate supplied to the DC heater j. auxiliary exhaust steam pressure k. feed water recirculated from the feed pump l. makeup feed introduced to the system - Answer B If the boiler water and condenser hot well levels are normal, but the DC heater level is only 30% of full, you should. m.increase the speed of the condensate pump n. open the feed pump recirculating valve wide o. open the makeup feed p. bypass the vent condenser and third-stage feed heater - Answer C 1

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 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. e. prime the condensate pump f. bypass the vent condenser g. slow the main unit h. 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? i. Root steam j. Auxiliary exhaust steam k. Main steam l. Auxiliary steam - Answer B In order to test the lifting pressure of the deaerating feed heater relief valve, you would . I. close the auxiliary exhaust dump valves to the main and auxiliary condenser II. increase the set point of the reduced steam pressure to the auxiliary exhaust system a. I only b. II only c. Both I and II d. Neither I nor II - Answer C Feed water is deaerated to prevent. m.cavitation in the feed pump n. corrosion in the boiler o. loss of system vacuum p. all of the above - Answer B A high water level in a deaerating feed heater will cause the automatic dump valve to drain condensate to the. q. atmospheric drain tank r. reserve feed tank s. auxiliary condenser t. main condenser - Answer B In a modern high pressure steam plant, most feed water deaeration takes place in the . 2

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. e. remove air from feed water f. heat feed water g. store feed water h. all of the above - Answer D In a closed feed water system, the greatest deaeration of condensate occurs in the . i. DC heater j. atmospheric drain tank k. air ejector condenser l. vent condenser - Answer A The purpose of the steam control valves installed in the auxiliary exhaust line is to . m.control steam admission and maintain the proper steam spray pattern in the DC heater n. regulate back pressure in the desuperheater line o. preheat the condensate before it enters the vent condenser p. seal the vent condenser to prevent the escape of condensate - Answer A The minimum design height of the DC heater is determined by the. q. dew point temperature of the stack gases r. minimum net positive suction head required by the main feed pump s. maximum condensate pump discharge pressure t. desuperheater outlet temperature - Answer B Why is it necessary to have a relief valve protect the deaerating feed tank from internal pressure? u. Because the tank receives auxiliary exhaust. v. Because the tank receives high pressure drains. w.Because the tank receives large amounts of water. x. 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. y. avoid running the feed pump 'dry' z. expel non-condensable vapors from the vent aa.thoroughly atomize incoming condensate 4

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? e. A malfunctioning auxiliary exhaust make-up steam regulating valve. f. Excessive deaeration of the feed water. g. Low back pressure in the auxiliary exhaust line. h. Low water level continually maintained in the DC heater. - Answer A Improper boiler feed water deaeration could be directly linked to. i. operating with excessive condensate depression j. fluctuating deaerating feed tank level as a result of taking on makeup feed too rapidly k. fluctuating condensate pressure due to not maintaining proper hot well level l. 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? m.Exhaust piping n. Pumps o. Check valve p. 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 Rapidly discharging condensate into the DC heater during normal steaming conditions could cause. q. decrease in auxiliary exhaust pressure r. decrease in dissolved oxygen in the feed water s. water hammer in the economizer t. increase in auxiliary exhaust pressure - Answer A Steam condensed in the air ejector intercondenser, drains to the. u. atmospheric drain tank v. after condenser drain tank w.vent condenser drain tank 5

II. maintain vacuum a. I only b. II only c. Both I and II d. Neither I nor II - Answer C Air accumulated in the intercondenser of the air ejector assembly is discharged directly to the. a. after condenser b. high pressure turbine c. main condenser d. atmosphere - Answer A What type of sensor is normally used with the automatic recirculating valve in the main condensate line? e. Thermostatic f. Pressurec. Continuity d. Preset electric timing sensor - Answer A If the condensate level in the loop seal of the intercondenser is lost,. g. no condensate will flow through the system h. some air will be drawn into the main condenser i. the air ejector will not operate j. the air ejector will become overheated - Answer B Serious tube leaks in the air ejector condenser assembly will cause. k. clogged steam strainers l. fouled nozzles m.loss of vacuum n. faulty steam pressure - Answer C In the condensate system, the automatic recirculating valve can be actuated by the . o. DC heater water level p. superheater steam flow q. condensate temperature r. condensate pump discharge pressure - Answer C Scale in the air ejector first-stage nozzle could cause a decrease in the. s. air ejector steam supply pressure t. low pressure turbine exhaust temperature u. condensing temperature in the condenser v. condenser vacuum - Answer D If the cooling water flow through the air ejector intercondensers and after condensers is inadequate, which of the problems listed will occur? 7

a. Air ejector nozzles will erode. b. After condenser will be flooded. c. DC heater level will rise d. Main condenser absolute pressure will increase. - Answer D Main condensate recirculating systems are primarily intended to. e. prevent excessive overheating of the condensate pumps f. balance and control condensate temperatures at full load g. provide adequate cooling water for the air ejector condensers - Answer C Which statement is true concerning two-stage air ejector assemblies? h. Air is removed from the condensate as it passes through the tubes. i.Steam to the after condenser is condensed and returned to the main condenser via the loop seal. j. The first stage air ejector takes suction on the second stage to increase vacuum. k.The steam/air mixture from the main condenser is discharged by the first stage air ejector to the inter condenser - Answer D The first and second stage air ejectors used with main steam condensers are designed to. I. establish vacuumII. increase condensate temperature a. I only b. II only c. Both I and II d. Neither I nor II - Answer C While vacuum is being raised on the main unit and the turbine is being warmed, condensate is recirculated to the main condenser to . l. ensure the condensation of air ejector steam m.cool the main condenser shell for better vacuum n. provide a condenser vacuum seal o. maintain a proper DC heater water level - Answer A Insufficient cooling water circulation through air ejector intercondensers and after condensers will cause. p. decreased vacuum in the main condenser q. overheating of the air ejector nozzles r. flooding of the after condenser s. flooding of the loop seal - Answer A Serious tube leaks in the air ejector after condenser assembly may cause . t. clogged steam strainers u. fouled nozzles v. an overflow of the contaminated drain inspection tank w.an overflow of the atmospheric drain tank - Answer D 8