中国电力科技论坛
标题:
《集控值班员》理论题
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作者:
华电之声
时间:
2008-4-24 11:31
标题:
《集控值班员》理论题
<p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">48</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">．汽轮机启动时为何排汽温度升高？</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">答：（</span><span lang="EN-US"><font face="Times New Roman">1</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">）汽轮机在启动过程中，调速汽门开启、全周进汽，通过主汽门控制汽轮机冲转、升速，</span><span lang="EN-US"><font face="Times New Roman">2040r/min</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">中速暖机后升速至</span><span lang="EN-US"><font face="Times New Roman">2900r/min</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">，进行阀切换后升速至</span><span lang="EN-US"><font face="Times New Roman">3000r/min</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">（</span><span lang="EN-US"><font face="Times New Roman">2</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">）在汽轮机启动过程中，蒸汽经节流后通过喷嘴去推动调速级叶轮，节流后的蒸汽焓值增加（焓降较小），以致作功后排汽温度较高。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">（</span><span lang="EN-US"><font face="Times New Roman">3</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">）在并网发电前的整个启动过程中，所耗汽量很少，这时作功主要依靠调节级、乏汽在流向排汽缸的通路中、流量小、流速低、通流截面大，产生了显著的鼓风作用。因鼓风损失较大而使排汽温度升高。在转子转动时，叶片（尤其末几级叶片较长）与蒸汽产生摩擦，也是使排汽温度升高的因素之一。汽轮机启动时真空较低，相对的饱和温度也将升高，即意味着排汽温度升高。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">（</span><span lang="EN-US"><font face="Times New Roman">4</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">）当并网发电升负荷后，主蒸汽流量随着负荷的增加而增加，汽轮机逐步进入正常工况，摩擦和鼓风损耗所占的功率份额越来越小。在汽轮机排汽缸真空逐步升高的同时，排汽温度也逐步降低。汽轮机启动时间过长，也可能使排汽温度过高。应按规程要求，控制机组启动时间，将排汽缸限制在限额内。汽轮机排汽温度不允许超过</span><chmetcnv wst="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="120" unitname="℃"><span lang="EN-US"><font face="Times New Roman">120</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">℃</span></chmetcnv><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">。</span></p>
作者:
zdfbzdfb
时间:
2010-4-3 20:33
感谢发帖，辛苦了 ，谢谢分享。
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