17.17. The products of combustion of marine fuels include sulfur dioxide, which, when combined with water vapor, forms acids such as the sulfurous acid and sulfuric acid. These acids cause cold-end corrosion if allowed to condense on boiler components of flue gas ducting. Therefore, in order to prevent the cold-end corrosion, which action is not to be taken?
(A) To ensure the temperature of exhaust gas is always above the condensation temperature level.
(B) To install more heat exchangers in the flue gas ducting so that the temperature of exhaust gas is further reduced.
(C) To prevent any chemical process that formulates the acid within the boiler components of flue gas ducting.
(D) To ensure there is no water-vapor condensate formed within the flue gas by controlling the flow temperatures in the flue-gas ducting.
18.18. For a seawater cooled condenser in a steam turbine power plant, which is the correct statement regarding the seawater temperature and the performances of condenser?
(A) Low seawater temperature permits high vacuum of condenser.
(B) Low seawater temperature permits high steam saturated temperature in condenser.
(C) Low seawater temperature permits high steam dryness in condenser.
(D) High seawater temperature permits high moisture rate of steam in condenser.
19.19. What device could permit for a higher-pressure source to supply a lower-pressure service, with an automatic response to changes in demand?
(A) Constant flow fitting
(B) Relief valve
(C) Stop valve
(D) Pressure-reducing valve
20.20. What ratio could be treated as the mechanical efficiency of a diesel engine?
(A) Brake mean effective pressure / Indicator mean effective pressure
(B) Indicator mean effective pressure / Brake mean effective pressure
(C) Mean effective pressure / Cycle maximum pressure
(D) Cycle maximum pressure / Cycle compression pressure
21.21. Flash evaporators generally use a “once through” system whereby the entire seawater feed is preheated through the stage condensers and seawater feed heater and allowed to flash down through the stages. The distilled water was produced at a pressure lower than the vapor pressure of the entering heated seawater. The resultant brine from the last stage is pumped
overboard. When the sea water was heated up to 85℃ fro normal operation, which following
statement is correct?
(A) The operating pressure inside the flash evaporator is less than atmospheric pressure.
(B) There is no brine produced in the flash evaporator.
(C) The fresh water generated inside this flash evaporator is suitable for direct drink of any crew member.
(D) The seawater is not evaporated in the flash evaporator due to low entry temperature.
30.30. Which technical term is quoted when the phase angles of voltage from two a-c generators are adjusted to be identical?
(A) Phase leading condition
(B) Voltage regulation
(C) Load shedding
31.31. Which feature is indicated by a gradually rising pressure in the crankcase of trunk piston diesel engines?
(A) Crankshaft wearing
(C) Water leakage
(D) Fuel dilution
39.39. Of all the waste heat available from internal-combustion engines, the heat in which flow has the largest availability and can be easily used to produce usable steam?
(B) Cooling water
(C) Lube oil
(D) Intake air
40.40. Which process can reduce the work required for multistage compression?
(A) Isentropic expansion
(B) Regenerative system
(D) Reciprocating compression