问题 问答题 简答题

启动过程中如何防止汽包壁温差过大?

答案

参考答案:

锅炉启动过程中要控制汽包壁温差不大于40℃,要注意崐以下几个方面。

(1)点火前的进水温度不能过高,速度不宜过快,严格按规程要求上水。

(2)锅炉上水后,点火前,尽量将低部加热投入。

(3)严格控制升压速度,注意汽压不到0.981MPa时,升崐压速度应不大于0.014MPa/min。

(4)按规程规定,定期切换油枪,使炉膛各部受热均匀。

(5)经上述操作仍不能有效控制汽包壁温差,可在汽包壁温差接近或达到40℃时暂停升压,并进行定期排污,以增强水循环,待汽包壁温稳定后再行升压。

阅读理解

Never give out identifying information such as Name, Home Address, School name, or Telephone Number in a public message such as at a chat room or on bulletin bards. Never send a person a picture of you without first checking with your parents or guardian.

● Never respond to messages or bulletin board items that are: Suggestive / Obscene / Belligerent / Threatening / Make You Feel Uncomfortable.

● Be careful when someone offers you something for nothing, such as gifts and money. Be very careful about any offers that involve your coming to a meeting or having someone visit your house.

● Tell your parents or guardian right away if you come across any information that makes you feel uncomfortable.

● Never arrange a face-to-face meeting without telling your parents or guardian. If your parents or guardian agree to the meeting, make sure that you meet in a public place and have a parent or guardian with you.

● Remember that people online may not be who they seem. Because you can’t see or even hear the person, it would be easy for someone to misrepresent him or herself. Thus, someone indicating that“she”is a“12-year-old-girl”could in reality be an older man.

● Be sure that you are dealing with someone that you and your parents know and trust before giving out any personal information about yourself via E-mail.

● Get to know your“online friends”just as you get to know all of your other friends.

小题1:We can infer from the passage that            .

A.it is not safe to surf the internet

B.people now are no longer honest

C.we can chat with unfamiliar people online

D.people online are not who they are小题2:Which of the following is right according to the passage?

A.People online never tell their friends their real names.

B.You can often get something free from the internet.

C.Your friends online may want to meet you.

D.Online friends are not friends at all.小题3:What is the main idea of the passage?

A.How to surf the internet.

B.Kids shouldn’t surf the internet.

C.How to choose online friends.

D.How to protect yourselves online.

单项选择题