单选题A vacuum is initially created in a flash type distilling plant by（）.Athe flashing of the feed waterBthe condensation of the saltwater feedCair ejectors, eductors, or a separate vacuum pumpDcondensation of the distillate
单选题
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
参考解析
解析：
暂无解析
相关考题：
In your database, the flash recovery area (FRA) is configured as the default for RMAN backups. You executed the following commands to configure the settings in RMAN:Which statement is true about the outcome?（）A. Only one channel is allocated and the backup is created in the flash recovery areaB. Only one channel is allocated and the backup is created in the destination specified for channelC. Two channels are allocated and backup sets are created in the destinations specified for channels 1 and 2D. Three channels are allocated and backup sets are created in the destinations specified for channels 1, 2, and FRA
In a flash type evaporator, all saltwater heaters are vented through individual vent cocks to the ______.A.saltwater heater shellB.second-stage condenserC.atmosphereD.second-stage flash chamber
You decided to change the location of the flash recovery area. You executed the following command： ALTER SYSTEM SET DB_RECOVERY_FILE_DEST=’+disk1’ SCOPE=BOTH SID=’*’； Which statement is true？（）A、 The location can be changed only if the flash recovery area is empty.B、 After executing the command， all new flash recovery area files will be created in the new location.C、 The command will generate an error because you cannot change the flash recovery area while the database is open.D、 All the existing files in the flash recovery area will be moved to the new location and all new Flash Recovery Area files will be created in the new location.
单选题One advantage of a flash distilling plant when compared to a submerged tube distiller is（）Agreater distillate purity through high temperature evaporationBcold shocking for scale removal is not requiredCless internal corrosion because of lower brine densityDless feed-water is required for equal plant capacity
单选题Excessive scale formation in a distilling plant may result from （）.Apoor distillate qualityBreduced evaporator capacityClow brine concentrationDimproper vacuum regulation
单选题The vacuum maintained in the salt water feed heater shell of a flash-type evaporator is generally accomplished by （）.Aa separate air ejector unitBa direct unimpeded connection between second stage and salt water feed heaterCeither by vacuum drag or an external line from the first stage via a fixed orificeDthe fixed orifice provided in the steam supply line
单选题You are using a radar in which your own ship is shown at the center，and the heading flash always points to 0°. If bearings are measured in relation to the flash，what type of bearings are produced? （）ARelativeBTRUECCompassDMagnetic
单选题In a flash type evaporator, all saltwater headers are vented through individual vent cocks to the（）.Asaltwater heater shellBsecond-stage condenserCatmosphereDsecond-stage flash chamber
单选题When distilling sea water the cooling water discharging from the distiller is fed back to evaporator as feed water （）.Ato decrease scale formationBfor better cooling effectCfor more economical purposeDto raise vacuum
单选题You decided to change the location of the flash recovery area. You executed the following command： Which statement is true？（）AThe location can be changed only if the flash recovery area is empty.BAfter executing the command， all new flash recovery area files will be created in the new location.CThe command will generate an error because you cannot change the flash recovery area while the database is open.DAll the existing files in the flash recovery area will be moved to the new location， and all new Flash Recovery Area files will be created in the new location.
单选题What is the operating principal of a flash type evaporator?（）ASea water is heated to boiling temperature under a vacuumBSea water is passed over heated plates in a thin filmCHeated sea water is injected into a vacuum chamberDSea water is forced through a heated eductor
单选题In the operation of a flash type evaporator equipped with air ejectors,the air and non- condensable gases are evacuated directly from the （）.Afirst stage flash chamberBsecond stage flash chamberCfirst stage after condenserDsecond stage distilling condenser
单选题In your database, the flash recovery area (FRA) is configured as the default for RMAN backups. You executed the following commands to configure the settings in RMAN: RMAN CONFIGURE DEVICE TYPE disk PARALLELISM 2 BACKUP TYPE TO BACKUPSET; RMAN CONFIGURE CHANNEL 1 DEVICE TYPE disk FORMAT '/home/oracle/disk1/%U'; RMAN CONFIGURE CHANNEL 2 DEVICE TYPE disk FORMAT '/home/oracle/disk2/%U'; You issue the following RMAN command to backup the database: RMAN RUN 2 { 3 ALLOCATE CHANNEL ch1 DEVICE TYPE disk; 4 BACKUP DATABASE; 5 } Which statement is true about the outcome?（）AOnly one channel is allocated and the backup is created in the flash recovery areaBOnly one channel is allocated and the backup is created in the destination specified for channel 1CTwo channels are allocated and backup sets are created in the destinations specified for channels 1 and 2DThree channels are allocated and backup sets are created in the destinations specified for channels 1, 2, and FRA
单选题You decided to change the location of the flash recovery area. You executed the following command： ALTER SYSTEM SET DB_RECOVERY_FILE_DEST=’+disk1’ SCOPE=BOTH SID=’*’； Which statement is true？（）A The location can be changed only if the flash recovery area is empty.B After executing the command， all new flash recovery area files will be created in the new location.C The command will generate an error because you cannot change the flash recovery area while the database is open.D All the existing files in the flash recovery area will be moved to the new location and all new Flash Recovery Area files will be created in the new location.
单选题The heated feedwater entering any flash chamber of a flash-type evaporator will（）Avaporize, with the unflashed water remaining at the temperature at which it entered the flash chamberBvaporize, with the unflashed water equalizing to the saturation conditions existing in the flash chamberCvaporize, with the remaining water at the temperature greater than it entered the flash chamberDboil, allowing steam bubbles to rise through the brine at the bottom of the flash chamber
单选题For a flash type evaporator, a demister is located the condenser（）AAfterBbeforeCinsideDoutside
单选题In a flash type evaporator, the brine overboard pump is vented directly to the（）Asaltwater heater shellBthe condensation of the saltwater feedCair ejectors, eductors, or a separate vacuum pumpDcondensation of the distillate
单选题The advantages of flash type evaporators, as compared to submerged tube type evaporators, include （）.Aless internal corrosion because of lower brine densityBhigher temperature evaporation for lower salinity of the distillate producedCless scale formation in a flash evaporatorDless feed-water required for a flash evaporator
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?（）ACondenser circulating water pumpBFeed-water heater drain pumpCDistillate pumpDAir ejector condenser drain pump
单选题Why will a two stage flash type distilling plant tend to operate more efficiently when operating in cold seawater?（）AThe colder seawater passing through the condenser tube bundles of the various stages increases evaporator vacuumBThe amount of heated feed water discharged from the feed water heater after cndenser is increasedCFewer non-condensable gases are created by the flow of colder seawaterDMore seawater is allowed to pass through the flint stage overflow weir
单选题The crankcase of many diesel engines are kept under a slight vacuum by the （）.Ascavenging action of the pistonBpiston type vacuum pump taking suction off a differential manometerCgland exhausting manometerDcrankcase exhaust fan
单选题In （）, hot diesel engine jacket water passes over the stack and heats the sea water passing through the tubes.Aa flash generatorBa flash evaporatorCa vacuum boiling evaporatorDa boiler
单选题The second stage feed-water temperature and shell absolute pressure in a multistage, flash type, distilling plant is （）Ahigher than the first stage feed-water temperature and absolute shell pressureBlower than the first stage feed-water temperature and absolute shell pressureCthe same as the first stage feed-water temperature and absolute shell pressureDnot related to the feed-water temperature and absolute shell pressure
单选题Which of the following descriptions best identifies the operating principal of a flash-type evaporator?（）ASea water is heated to boiling temperature while under a vacuumBSea water is passed over heated plates in a thin filmCHeated sea water is injected into a vacuum chamberDSea water is forced through a heated eductor
单选题Which one of the followings might not be employed to create vacuum for flash type evaporator? （）Ahigh-pressure steam-driven air-ejectorBmotor-driven vacuum pumpCwater-motivated air eductorDcentrifuge pump
单选题In a flash distilling unit, evaporator feed (seawater) first absorbs heat in the （）.Avapor feed heaterBair ejector condenserCsaltwater heaterDdistillate cooler
单选题A vacuum is initially established in the first and second stages of a low pressure evaporator by the use of （）Avacuum drag from the auxiliary condensate systemBindividual vacuum pumpsCa single non-condensing air ejectorDa two stage air ejector