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单选题
The vacuum maintained in the salt water feed heater shell of a flash-type evaporator is generally accomplished by （）.
A
a separate air ejector unit
B
a direct unimpeded connection between second stage and salt water feed heater
C
either by vacuum drag or an external line from the first stage via a fixed orifice
D
the fixed orifice provided in the steam supply line
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更多 “单选题The vacuum maintained in the salt water feed heater shell of a flash-type evaporator is generally accomplished by （）.A a separate air ejector unitB a direct unimpeded connection between second stage and salt water feed heaterC either by vacuum drag or an external line from the first stage via a fixed orificeD the fixed orifice provided in the steam supply line” 相关考题
考题
If the feed pump for an auxiliary boiler fails to deliver the feed water to the boiler, the cause may be ______.A.high steam pressure in the boilerB.abnormally high feed-water temperatureC.abnormally high boiler water temperatureD.steam demand exceeding feed pump capacity
考题
单选题Which of the following items is necessary for all waste heat boiler installations, regardless of design or manufacturer? （）A
Control of evaporationB
A separate means to prevent feed-water contaminationC
Power circulating pumpD
Super-heater
考题
单选题The most common cause of scale formation in an auxiliary boiler is （）A
concentrations of calcium sulfate in the boiler waterB
fuel oil in the feed waterC
improper treatment of the feed water with calcium sulfateD
excessive feed water alkalinity
考题
单选题Passage2 Questions 6 to 10 are based on the following passage. Salt is as necessary to life as water. In many areas of Africa people once drank the urine（尿）of animals because they had no other source of salt. Without salt, human beings die. The human body demands that the amount of salt in the blood always stay the same. When the body does not get enough salt, it protects itself by letting less salt leave the body in. urine and sweat. But it cannot reduce this output to zero. Some salt is always escaping. On a completely saltless diet, like that of some people in Africa, the body steadily loses small amounts of salt through the kidneys（肾） and sweat glands(腺). It then tries to adjust to this loss by speeding up its secretion(分泌) of water. (78) In this way, the body attempts to keep the amount of salt in the blood at the necessary level. The result is a slow drying up of body and, finally, death. The person dies of thirst. In cases where there is little or no water to drink, the body tries to do the opposite thing.Again, it must keep the salt level in the blood constant. Because it has little water, it attempts to stop water from leaving the body and to increase its secretion of. salt. But, as with the escaping salt, it cannot be completely successful. Some water still leaves and the person eventually dies of thirst. In short, the body's normal needs for salt and for water are both parts of the same important need to keep the salt level in the blood constant.6 Some African people once drank animal urine______.A
when they were going to dieB
because they were thirstyC
because there was little saltD
because they were short of water
考题
单选题When distilling sea water the cooling water discharging from the distiller is fed back to evaporator as feed water （）.A
to decrease scale formationB
for better cooling effectC
for more economical purposeD
to raise vacuum
考题
单选题Passage2 Questions 6 to 10 are based on the following passage. Salt is as necessary to life as water. In many areas of Africa people once drank the urine（尿）of animals because they had no other source of salt. Without salt, human beings die. The human body demands that the amount of salt in the blood always stay the same. When the body does not get enough salt, it protects itself by letting less salt leave the body in. urine and sweat. But it cannot reduce this output to zero. Some salt is always escaping. On a completely saltless diet, like that of some people in Africa, the body steadily loses small amounts of salt through the kidneys（肾） and sweat glands(腺). It then tries to adjust to this loss by speeding up its secretion(分泌) of water. (78) In this way, the body attempts to keep the amount of salt in the blood at the necessary level. The result is a slow drying up of body and, finally, death. The person dies of thirst. In cases where there is little or no water to drink, the body tries to do the opposite thing.Again, it must keep the salt level in the blood constant. Because it has little water, it attempts to stop water from leaving the body and to increase its secretion of. salt. But, as with the escaping salt, it cannot be completely successful. Some water still leaves and the person eventually dies of thirst. In short, the body's normal needs for salt and for water are both parts of the same important need to keep the salt level in the blood constant.10 What is the main idea of the passage?A
Salt is very important.B
If their blood salt level is not constant, human beings may die.C
The amount of salt in the body is secreted.D
People can die of thirst.
考题
单选题A salinity indicator is used to determine the （）.A
cause of salt contaminationB
location of salt water contaminationC
chemical makeup of feed-waterD
level of alkalinity in condensate
考题
单选题When distilling salt water the cooling water discharging from the distiller is fed back to evaporator as feed water （）.A
to cut down the amount of cooling water neededB
to prevent an excess amount of cooling water from being discharged to the bilgesC
to supply hot water to the evaporator for more economical operationD
None of the above is tree
考题
单选题In a flash type evaporator, the brine overboard pump is vented directly to the（）A
saltwater heater shellB
the condensation of the saltwater feedC
air ejectors, eductors, or a separate vacuum pumpD
condensation of the distillate
考题
单选题In the two stage flash distilling plant, which of the pumps listed is vented to the shell of the second stage in order to remove vapor from the pump suction?（）A
Condenser circulating water pumpB
Feed-water heater drain pumpC
Distillate pumpD
Air ejector condenser drain pump
考题
单选题On a multistage flash-type evaporator, the flash chamber is （）A
combined as part of the salt water feed heaterB
the open area above the brine levels in the first and second stagesC
combined as part of the distillate coolerD
another term used to describe the vapor feed heater
考题
单选题Why will a two stage flash type distilling plant tend to operate more efficiently when operating in cold seawater?（）A
The colder seawater passing through the condenser tube bundles of the various stages increases evaporator vacuumB
The amount of heated feed water discharged from the feed water heater after cndenser is increasedC
Fewer non-condensable gases are created by the flow of colder seawaterD
More seawater is allowed to pass through the flint stage overflow weir
考题
单选题The second stage feed-water temperature and shell absolute pressure in a multistage, flash type, distilling plant is （）A
higher than the first stage feed-water temperature and absolute shell pressureB
lower than the first stage feed-water temperature and absolute shell pressureC
the same as the first stage feed-water temperature and absolute shell pressureD
not related to the feed-water temperature and absolute shell pressure
考题
单选题With a vacuum boiling evaporator, the remainder of sea water fed to the evaporator is pumped out by （）.A
a brine pumpB
an air ejectorC
a feed pumpD
distillate pump
考题
单选题Passage2 Questions 6 to 10 are based on the following passage. Salt is as necessary to life as water. In many areas of Africa people once drank the urine（尿）of animals because they had no other source of salt. Without salt, human beings die. The human body demands that the amount of salt in the blood always stay the same. When the body does not get enough salt, it protects itself by letting less salt leave the body in. urine and sweat. But it cannot reduce this output to zero. Some salt is always escaping. On a completely saltless diet, like that of some people in Africa, the body steadily loses small amounts of salt through the kidneys（肾） and sweat glands(腺). It then tries to adjust to this loss by speeding up its secretion(分泌) of water. (78) In this way, the body attempts to keep the amount of salt in the blood at the necessary level. The result is a slow drying up of body and, finally, death. The person dies of thirst. In cases where there is little or no water to drink, the body tries to do the opposite thing.Again, it must keep the salt level in the blood constant. Because it has little water, it attempts to stop water from leaving the body and to increase its secretion of. salt. But, as with the escaping salt, it cannot be completely successful. Some water still leaves and the person eventually dies of thirst. In short, the body's normal needs for salt and for water are both parts of the same important need to keep the salt level in the blood constant.7 In order to adjust to the loss of salt, the body______.A
loses some bloodB
speeds up its secretion of waterC
speeds up its secretion of saltD
is drying up slowly
考题
单选题Early models of the flash-type evaporators used a separate shell-and-tube heat exchanger as the air ejector condenser.More recent models use a combined air ejector condenser with the（）A
distilling condenserB
salt water feed heaterC
distillate coolerD
flash chamber
考题
单选题Which of the listed conditions will cause the feed water that has not flashed to vapor in the first-stage of a flash evaporator, to flow into the second-stage?（）A
Gravity siphon effectB
Higher vacuum in the second-stageC
Difference in brine density between first and second stagesD
lower pressure in first-stage
考题
单选题In which of the areas listed would you expect to find the highest salt concentration in a flash evaporator?（）A
Distiller air ejector cooling mediumB
Saltwater heater dischargeC
First-stage internal feed boxD
Second-stage internal feed box
考题
单选题In a vacuum boiling evaporator, the fresh water generated is pumped out by （）.A
a brine pumpB
an air ejectorC
a feed water pumpD
a condensate pump
考题
单选题Under normal operating conditions, the highest temperature and pressure conditions existing in a flash-type evaporator will occur in the （）.A
first stageB
second stageC
distillate coolerD
salt water feed heater
考题
单选题The boiler feed pump discharge pressure is higher than the steam drum pressure to （）.A
ensure feed water flow into the boilerB
keep the steam drum pressure highC
prevent water hammer in the feed lineD
help the feed water flash to steam
考题
单选题In motorships，there are two main circuits, （）.A
one salt water, one fresh waterB
one salt water, one fuelC
one fresh water, one fuelD
one steam, one fuel
考题
单选题A vacuum is initially created in a flash type distilling plant by（）.A
the flashing of the feed waterB
the condensation of the saltwater feedC
air ejectors, eductors, or a separate vacuum pumpD
condensation of the distillate
考题
单选题If the feed pump for an auxiliary boiler fails to deliver the feed water to the boiler, the cause maybe （）.A
high steam pressure in the boilerB
abnormally high feed water temperatureC
abnormally high boiler water temperatureD
steam demand exceeding feed pump capacity
考题
单选题Passage2 Questions 6 to 10 are based on the following passage. Salt is as necessary to life as water. In many areas of Africa people once drank the urine（尿）of animals because they had no other source of salt. Without salt, human beings die. The human body demands that the amount of salt in the blood always stay the same. When the body does not get enough salt, it protects itself by letting less salt leave the body in. urine and sweat. But it cannot reduce this output to zero. Some salt is always escaping. On a completely saltless diet, like that of some people in Africa, the body steadily loses small amounts of salt through the kidneys（肾） and sweat glands(腺). It then tries to adjust to this loss by speeding up its secretion(分泌) of water. (78) In this way, the body attempts to keep the amount of salt in the blood at the necessary level. The result is a slow drying up of body and, finally, death. The person dies of thirst. In cases where there is little or no water to drink, the body tries to do the opposite thing.Again, it must keep the salt level in the blood constant. Because it has little water, it attempts to stop water from leaving the body and to increase its secretion of. salt. But, as with the escaping salt, it cannot be completely successful. Some water still leaves and the person eventually dies of thirst. In short, the body's normal needs for salt and for water are both parts of the same important need to keep the salt level in the blood constant.8 Which of the following statements is NOT the result of a lack of salt in the body?A
The body secretes more water.B
The body dries up.C
The person dies of thirst.D
The person gets fatter.
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