问题 问答题 简答题

锅炉冷态启动升温升压的一般规定及操作程序?

答案

参考答案:

锅炉在升压升温过程中的一般规定

(1)锅炉从点火至并列时间,中压锅炉一般为2~3小时,并按饱和蒸汽温度平均温升1~1.5℃/min进行升压。

(2)在升压升温过程中,应控制汽包上、下壁温不超50℃。

(3)在升压、升温过程中,应注意调整燃烧,保持炉内温度均匀上升,承压部件受热均衡。

(4)严禁关小过热器出口联箱疏水阀或向空排汽赶火升压,以免过热器管壁温度急剧升高。

(5)在升压、升温过程中,应开启过热器出口联箱疏水阀,使过热器得到足够的冷却。

(6)在升温、升压过程中,应监视过热器蒸汽温度及过热器管壁温度变化,蒸汽温度不得超过其确定值,管壁温度不得超过金属允许承受的温度。

(7)在升压、升温期间,省煤器与汽包再循环阀必须开启,在锅炉进水时应将再循环阀关闭。

(8)在升压、升温过程中,应利用膨胀指示器监视各承压部件的膨胀情况,记录膨胀指示的数据,若指示异常,应查明原因,予以消除。

(9)如因局部受热不均而影响膨胀时,应在联箱膨胀较小的一端进行放水,使其受热均匀,如系承压部件卡住,则应停止升压,待故障消除后继续升压。

(10)在升压过程中,应经常监视汽包水位的变化,并维持正常水位。

锅炉在升压升温过程中的操作程序

(1)当汽包压力升至0.1~0.2MPa,关闭汽包空气阀,并冲洗校对汽包水位计。

(2)当汽压升至0.2~0.3MPa时,通知热工、化学值班人员冲洗仪表导管及化学取样管。

(3)当汽压升至0.2~0.4MPa时,进行锅炉下联箱的放水。

(4)对检修后的锅炉,当汽压升至0.3MPa时,应通知检修人员热紧法兰、人孔及手孔等处的螺栓,此时应保持汽压稳定。

(5)当汽压升至工作压力50%时,应对锅炉机组进行全面检查,如发现异常,应停止升压,待故障消除后继续升压。

(6)经过检修的安全阀,在锅炉并列前应进行调整与试验,以确保安全阀动作准确、可靠。

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根据短文内容回答问题

    Students study lots of subjects at school, like Maths, Chinese, English and Music. Most students think

it’s hard to do well in Maths. They say it’s boring. Why do they say so? First, some Maths problems (问题) are so hard that they can’t work them out. They spend lots of time on them, but they can’t work

them out, so they lose heart (丧失信心). Second, they are afraid to ask their teachers for help. They

think the teachers will laugh at them. Third, they think Maths classes are very tiring (累人的) as they

need to use their brain (脑) to work out the answers to the questions.

    How can you do well in Maths? Here is some advice (建议) from a teacher:

    1. Listen to the teacher carefully in class and do extra (额外的) exercises after class.

    2. Ask your teachers for help if you don’t understand something. Don’t be afraid. Your teachers are

always glad to help you.

    3. Don’t forget to go over your lessons. Then you will be able to understand each question better.

1. How many pieces of advice does the writer give us on how to do well in Maths?

    ____________________________________

2. What do most students think of Maths?

    ____________________________________

3. Why do students sometimes lose heart in learning maths?

    ____________________________________

4. How should you do it if you don’t understand something?

    ____________________________________

5. What should you do in Maths classes if you want to learn Maths well? (请你根据自己的想法,自拟一句话作答)

    ____________________________________