问题 问答题 简答题

汽轮机启动前应投运哪些辅助系统?

答案

参考答案:

1)投运辅汽联箱,调节高压联箱压力在1.5MPa范围,此时汽温约350℃;低压联箱压力在0.4MPa范围,温度260℃。

2)检查冷却塔及综合泵房补水池水位正常,投入工业水及冷却水系统;

3)确证凝汽器进、出水门已开启,启动循环水泵,向循环水系统充水排空气;

4)启动交流润滑油泵及排烟风机,向润滑油系统充油排气;

5)将发电机密封油箱加油至正常油位后,启动主密封油泵,投入发电机密封油系统;

6)发电机充氢结束,氢压及氢纯度正常,检查油/氢差压正常;

7)启动定子冷却水泵,投入发电机水冷系统;

8)启动两台顶轴油泵,检查顶轴油压正常,确证大轴已顶起,投入盘车;

9)投运凝结水系统,进行凝结水再循环,并投入精处理装置;

10)缓慢开启除氧器水位调整门向各低加充水排气,并向除氧器上水至正常水位;

11)确认除氧器水质合格,启动除氧器再循环泵,检查运行正常;

12)开启辅汽联箱至除氧器进汽调整门,加热除氧水温至炉要求;

13)启动一台给水泵,向炉上水;

14)投运EH油系统,进行油循环;

15)启动高、低压旁路控制油站,检查油压正常;

16)启动两台真空泵,检查凝汽器真空逐渐建立;

17)投入轴封系统,启动轴封风机;

18)当凝汽器真空达20KPa时,锅炉点火;

19)投入旁路系统,并利用旁路辅助调节升温升压率,注意高压排汽缸温度及凝汽器真空的变化,及时投入低压缸喷水;

20)当凝汽器真空达80KPa以上时,可停止一台真空泵运行,并注意此时真空变化;

21)检查各疏水管疏水畅通,并及时向各疏水扩容器投入减温水。

阅读理解

阅读理解

     I'm usually fairly skeptical about any research that concludes that people are either happier or

unhappier or more or less certain of themselves than they were 50 years ago. While any of these

statements might be true, they are practically impossible to prove scientifically. Still, I was struck

by a report which concluded that today's children are significantly more anxious than children in

the 1950s. In fact, the analysis showed, normal children aged 9 to 17 exhibit a higher level of

anxiety today than children who were treated for mental illness 50 years ago.

     Why are America's kids so stressed? The report cites two main causes: increasing physical

isolation(隔离) brought on by high divorce rates and less involvement in community, among other

things and a growing perception that the world is a more dangerous place.

Considering that we_can't_turn_the_clock_back,_adults can still do plenty to help the next generation.

     At the top of the list is nurturing(培育) a better appreciation of the limits of individualism. No

child is an island. Strengthening social ties helps build communities and protect individuals against

stress.

     To help kids build stronger connections with others, you can pull the plug on TVs and computers.

Your family will thank you later. They will have more time for facetoface relationships, and they will

get more sleep.

    Limit the amount of virtual(虚拟的) violence your children are exposed to. It's not just video

games and movies; children see a lot of murder and crime on the local news.

    Keep your expectations for your children reasonable. Many highly successful people never attended

Harvard or Yale.

    Make exercise part of your daily routine. It will help you cope with your own anxieties and provide

a good model for your kids. Sometimes anxiety is unavoidable. But it doesn't have to ruin your life.

1. According to the analysis, compared with normal children today, children treated as

    mentally ill 50 years ago ________.

A. probably suffered less from anxiety

B. were considered less individualistic

C. were less isolated physically

D. were probably less selfcentered

2. What does the author mean by saying "we can't turn the clock back" in the third paragraph?

A. It's impossible to forget the past.

B. The social reality children are facing cannot be forgotten.

C. It's impossible to slow down the pace of change.

D. Lessons learned from the past should not be forgotten.

3. The author thinks that the conclusions of any research about people's state of mind are ________.

A. illogical  

B. confusing

C. surprising  

D. questionable

4. Which of the following statements is TRUE according to the passage?

A. To children, anxiety is completely avoidable.

B. TV and computer play an important role in isolating children from the real world.

C. Exercise does not help to lessen children's anxiety.

D. Sometimes local news about crime and murder also affects children a little.

5. The first and most important thing parents should do to help their children is________.

A. to lower their expectations for them

B. to set a good model for them to follow

C. to get them more involved socially

D. to improve them with a safer environment

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