问题 问答题

试述凝汽器真空下降的处理原则?

答案

参考答案:

(1)发现真空下降,应对照排汽温度,确认真空下降,应迅速查明原因,立即采取相应的对策进行处理,并汇报上级领导。

(2)真空下降应启动备用真空泵,如真空跌至88千帕仍继续下降,则应按每下降1千帕机组减负荷50MW,真空降至82千帕时减负荷到零。

(3)经处理无效,真空下降至82千帕,机组负荷虽减到零真空仍无法恢复,应打闸停机。

(4)真空下降时,应注意汽泵的运行情况,必要时切换至电动泵运行。

(5)真空下降,应注意排汽温度的变化,达80摄氏度时投入后缸喷水;如排汽温度上升至121摄氏度运行时间达15分钟或排汽温度超过121摄氏度,应打闸停机。

(6)如真空下降较快,在处理过程中已下降至81千帕,保护动作机组跳闸,否则应手动打闸停机。

(7)因真空低停机时,应及时切除并关闭高、低压旁路,关闭主、再热蒸汽管道至凝汽器疏水,禁止开启锅炉至凝汽器的5%旁路。

(8)加强对机组各轴承温度和振动情况的监视。

填空题
阅读理解

Some people will do just about anything to save money. And I am one of them. Take my family’s last vacation. It was my six-year-old son’s winter break form school, and we were heading home from Fort Lauderdale after a weeklong trip. The flight was overbooked, and Delta, the airline, offered us $400 per person in credits to give up our seats and leave the next day. I had meeting in New York,So I had to get back . But that didn't mean my husband and my son couldn't stay. I took my nine-month-old and took off for home.

The next day my husband and son were offered more credits to take an even later flight. Yes, I encouraged一okay, ordered-them to wait it out at the airport, to "earn" more Delta Dollars. Our total take: $1,600. Not bad, huh?

Now some people may think I'm a bad mother and not such a great wife either. But as a big-time bargain hunter, I know the value of a dollar. And these days, a good deal is something few of us can afford to pass up.

I've made living looking for the best deals and exposing (揭露) the worst tricks . I have been the consumer reporter of NBC's Today show for over a decade. I have written a couple of books including one titled Tricks of the Trade: A Consumer Survival Guide. And I really do what I believe in. I tell you this because there is no shame in getting your money’s worth. I’m also tightfisted when it comes to shoes, clothes for my children, and expensive restaurants. But I wouldn't hesitate to spend on a good haircut. It keeps its longer, and it's the first thing people notice. And I will also spend on a classic piece of furniture. Quality lasts.

小题1:Why did Delta give the author's family credits?

A.They took a later flight.

B.They had early bookings.

C.Their flight had been delayed.

D.Their flight had been cancelled.小题2:What can we learn about the author?

A.She rarely misses a good deal.

B.She seldom makes a compromise.

C.She is very strict with her children

D.She is interested in cheap products.小题3:What does the author do?

A.She's a teacher.

B.She's a housewife.

C.She's a media person.

D.She's a businesswoman.小题4:What does the author want to tell us?

A.How to expose bad tricks.

B.How to reserve airline seats.

C.How to spend money wisely,

D.How to make a business deal.