更多"For a flash type evaporator, the se"的相关试题:
[单项选择]A flash-type evaporator discharges heated seawater into a chamber that is maintained at a pressure than the vapor pressure of the entering heated seawater, and subsequently the flashed water vapor thereby produced（）
A. lower condensing
B. higher cooling
C. lower cooling
D. higher condensing
[单项选择]One distinct advantage of flash type evaporators, as compared to most other evaporators, is that in a flash evaporator （）.
A. high temperature distillate can be re- circulated to induce additional flashing
B. scale formation is not a severe problem
C. cold shocking is more effective in removing scale
D. water purity is greatly increased at high capacity
[单项选择]In the operation of a flash type evaporator equipped with air ejectors,the air and non- condensable gases are evacuated directly from the （）.
A. first stage flash chamber
B. second stage flash chamber
C. first stage after condenser
D. second stage distilling condenser
[单项选择]In a flash type evaporator, all saltwater headers are vented through individual vent cocks to the（）.
A. saltwater heater shell
B. second-stage condenser
C. atmosphere
D. second-stage flash chamber
[单项选择]The advantages of flash type evaporators, as compared to submerged tube type evaporators, include （）.
A. less internal corrosion because of lower brine density
B. higher temperature evaporation for lower salinity of the distillate produced
C. less scale formation in a flash evaporator
D. less feed-water required for a flash evaporator
[单项选择]What is the operating principal of a flash type evaporator?（）
A. Sea water is heated to boiling temperature under a vacuum
B. Sea water is passed over heated plates in a thin film
C. Heated sea water is injected into a vacuum chamber
D. Sea water is forced through a heated eductor
[单项选择]In a flash type evaporator, the brine overboard pump is vented directly to the（）
A. saltwater heater shell
B. the condensation of the saltwater feed
C. air ejectors, eductors, or a separate vacuum pump
D. condensation of the distillate
[单项选择]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 vacuum
B. The amount of heated feed water discharged from the feed water heater after cndenser is increased
C. Fewer non-condensable gases are created by the flow of colder seawater
D. More seawater is allowed to pass through the flint stage overflow weir
[单项选择]The efficiency of a flash type evaporator can be increased by（）
A. lowering brine discharge density
B. decreasing the absolute pressure of each stage
C. increasing the saltwater feed heater temperature
D. increasing the pressure at the spray pipe
[单项选择]For a flash type evaporator, a demister is located the condenser（）
A. After
B. before
C. inside
D. outside
[单项选择]A vacuum is initially created in a flash type distilling plant by（）.
A. the flashing of the feed water
B. the condensation of the saltwater feed
C. air ejectors, eductors, or a separate vacuum pump
D. condensation of the distillate
[单项选择]The design of for a flash type evaporator is of critical importance because it must provide an optimum feedwater spray pattern that facilitates the flashing process, and it must also maintain a pressure differential between successive stages（）
A. condenser
B. flashing device
C. lashing device
D. vacuum pump
[单项选择]On a multistage flash-type evaporator, the flash chamber is （）
A. combined as part of the salt water feed heater
B. the open area above the brine levels in the first and second stages
C. combined as part of the distillate cooler
D. another term used to describe the vapor feed heater
[单项选择]The demisters installed in a flash-type evaporator serve to （）
A. deaerate the first effect distillate
B. filter the condensed flash vapors
C. deaerate the first and second effect distillate
D. remove small water droplets entrained in the flashed vapor
[单项选择]When securing a flash-type evaporator for an extended period of time, you should （）.
A. fill the unit with saltwater
B. fill the unit with de-scaling compound
C. completely drain the unit
D. tightly seal the unit to exclude air
[单项选择]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 condenser
B. salt water feed heater
C. distillate cooler
D. flash chamber
[单项选择]When a flash-type evaporator is to be secured for an extended period of time, the entire unit should be drained, cleaned, and （）.
A. completely filled with saltwater
B. filled with de-scaling compound
C. tightly closed to exclude air
D. vented to the atmosphere
[单项选择]An electric heater built into some smaller diesel engines is used to （）.
A. raise lube oil viscosity for easier starting in cold weather
B. increase air inlet temperature
C. increase compression ratio
D. increase jacket water temperature for easier starting in cold weather
[单项选择]The main purpose of an electric space heater installed in a large AC generator is to （）
A. prevent the windings from becoming brittle
B. prevent moisture from condensing in the windings during shutdown
C. prevent acidic pitting of the slip rings
D. keep the lube oil warm for quick starting
