问题 问答题 简答题

什么是物料的循环倍率K?物料的循环过程由哪些过程组成?

答案

参考答案:

单位时间内CFB外循环物料量与入炉固体燃料的比值,称为物料的循环倍率K,或称CFB锅炉的循环倍率。公式表述为K=G/B 

G——循环物料的质量流速,B——燃料的质量流速。 

物料循环过程由内循环和外循环两部分组成。内循环主要指循环床燃烧室内部流化的物料沿高度自身存在的颗粒上下质交换现象。由于循环床燃烧室边壁效应的原因,沿边壁存在着较为明显的下降流,而燃烧室中心区颗粒上长趋势较为明显。人们从这个现象引申颗粒在燃烧室内的上下质交换为内循环。而烟气携带的物料从燃烧室出口进入循环床分离器被分离后送回燃烧室则称为外循环。

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Whenever you want to make a decision, just make sure to think twice and confirm it. This is what we learn from the following story. While two old beggars were sitting on a        street corner, they watched helplessly as scores of people walked by. Some purposely       them and others too caught up in their own cares didn’t even notice their        . Every so often, a kind-hearted woman or a small child would drop a few coins in the       which lay in front of them.
As the crowd began to die down, they started to           their things and head for their evening      . Just as they were getting ready to leave, they noticed a man walking toward them. He was obviously a         man—they could tell that from his finely tailored business suit.
The first beggar whispered to the second with          , “He’s coming our way!”
The two tried not to look         at the man as he stepped closer to them, but they couldn’t          gazing up with anticipation         he reached into his pocket and took something out.
“Thunk” was the only sound they heard as what looked like a piece of hard        , wrapped in tissue paper hit each of their waiting hats. The rich man           and continued on his way, not making a backward glance.
“How insulting(侮辱人的)!” said the first beggar. “He could have          left us a few coins or a spare bill, but he mocks us with a piece of rock candy. Who does he think we are?        ? There’s no way we can even eat this—we have no         .” He picked up the object and threw it into the gutter.
“I haven’t had anything like this for ages,” the second beggar thought. “I can’t chew it, but I can suck on it      , and the sugary juices will stay in my          for a long time. How nice of that man to offer me something so sweet!”
With that, he         the white tissue paper, but to his        , there was no hard rock candy inside. However, into his fingers fell a shiny white pearl worth thousands of dollars.
小题1:
A.distantB.busyC.broadD.narrow
小题2:
A.aidedB.observedC.noticedD.ignored
小题3:
A.existenceB.situationC.appearanceD.expression
小题4:
A.hatsB.handsC.pocketsD.bowls
小题5:
A.put upB.cover upC.pack upD.end up
小题6:
A.partyB.flatC.shelterD.shadow
小题7:
A.wealthyB.healthyC.poorD.proud
小题8:
A.confusionB.happinessC.excitementD.amusement
小题9:
A.carelesslyB.calmlyC.sadlyD.directly
小题10:
A.helpB.escapeC.waitD.prevent
小题11:
A.thenB.whileC.asD.since
小题12:
A.cakeB.candyC.coinD.bill
小题13:
A.quitB.declinedC.turnedD.returned
小题14:
A.easilyB.hardlyC.suddenlyD.finally
小题15:
A.BabiesB.ChildrenC.AdultsD.Old men
小题16:
A.handsB.teethC.bowlsD.money
小题17:
A.in a whileB.for a whileC.after a whileD.once in a while
小题18:
A.pocketB.handC.mouthD.hat
小题19:
A.threwB.undertookC.unfoldedD.wrapped
小题20:
A.satisfactionB.amazementC.horrorD.disappointment