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
In a flash distilling unit, evaporator feed (seawater) first absorbs heat in the （）.
A
vapor feed heater
B
air ejector condenser
C
saltwater heater
D
distillate cooler
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相关考题：
Which of the listed problems could produce a high absolute pressure within a flash type evaporator?A.production of high salinity distillateB.seawater feed temperature below 165℃C.a leak in the first stage demisterD.a cracked distillate pump vent line
单选题When a flash-type evaporator is to be secured for an extended period of time, the entire unit should be drained, cleaned, and （）.Acompletely filled with saltwaterBfilled with de-scaling compoundCtightly closed to exclude airDvented to the atmosphere
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（）Alower condensingBhigher coolingClower coolingDhigher condensing
单选题The heated feed-water entering any flash chamber of a flash-type evaporator will（）Avaporize, with the un-flashed water remaining at the temperature at which it entered the flash chamberBvaporize, with the un-flashed eater equalizing to the saturation conditions existing in the f lash chamberCvaporize, with the remaining water a t a 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Which of the listed problems could produce a high absolute pressure within a flash type evaporator?（）AProduction of high salinity distillateBSeawater feed temperature below 165℃CA leak in the first stage demisterDA cracked distillate pump vent line
单选题Tube leaks in the distillate cooler of a two stage flash evaporator will result in （）.Aloss of second stage vacuumBcontamination of the distillateClower feed inlet temperatureDcontamination of the second stage condenser
单选题For a flash type evaporator, the seawater heater will have to maintain a enough temperature to minimize scale formation（）AlowerBhigherClowDhigh
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The demisters installed in a flash-type evaporator serve to （）Adeaerate the first effect distillateBfilter the condensed flash vaporsCdeaerate the first and second effect distillateDremove small water droplets entrained in the flashed vapor
单选题Less scale formation occurs in a flash evaporator than in a submerged tube evaporator because （）.Athe distillate produced has greater purityBno boiling occurs on heat transfer surfacesCevaporation occurs at a higher rateDthe incoming feed is at a higher temperature
单选题When distilling salt water the cooling water discharging from the distiller is fed back to evaporator as feed water （）.Ato cut down the amount of cooling water neededBto prevent an excess amount of cooling water from being discharged to the bilgesCto supply hot water to the evaporator for more economical operationDNone of the above is tree
单选题For a flash type evaporator, a demister is located the condenser（）AAfterBbeforeCinsideDoutside
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On a multistage flash-type evaporator, the flash chamber is （）Acombined as part of the salt water feed heaterBthe open area above the brine levels in the first and second stagesCcombined as part of the distillate coolerDanother term used to describe the vapor feed heater
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 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With a vacuum boiling evaporator, the remainder of sea water fed to the evaporator is pumped out by （）.Aa brine pumpBan air ejectorCa feed pumpDdistillate pump
单选题In a flash evaporator, scale as a result of higher than normal temperatures in most likely to occur in the （）Asecond stage feed heaterBsaltwater feed heaterCdistillate coolerDsecond stage vapor separator
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?（）AGravity siphon effectBHigher vacuum in the second-stageCDifference in brine density between first and second stagesDlower pressure in first-stage
单选题In which of the areas listed would you expect to find the highest salt concentration in a flash evaporator?（）ADistiller air ejector cooling mediumBSaltwater heater dischargeCFirst-stage internal feed boxDSecond-stage internal feed box
单选题Under normal operating conditions, the highest temperature and pressure conditions existing in a flash-type evaporator will occur in the （）.Afirst stageBsecond stageCdistillate coolerDsalt water feed heater
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When securing a flash-type evaporator for an extended period of time, you should （）.Afill the unit with saltwaterBfill the unit with de-scaling compoundCcompletely drain the unitDtightly seal the unit to exclude air