600MW機(jī)組凝結(jié)水含氧量超標(biāo)的危害和預(yù)防.pptx

1、600MW機(jī)組凝結(jié)水含氧量超標(biāo)的危害和預(yù)防,600MW units condensate oxygen content of the hazards of excessive and prevention,Condensate of dissolved oxygen is one of the main indicators of the chemical supervision ，600MW units condensate dissolved oxygen content higher dissolved oxygen ，because a lot of excessive or long

2、 - term failure, It will accelerate the condensate pipeline and equipment corrosion,and make condensat contains iron oxide ions , causing galvanic corrosion，Heat transfer deterioration , until the occurrence of boiler tube , and crew safety and economic operation of units.,凝結(jié)水溶解氧是化學(xué)監(jiān)督的主要指標(biāo)之一,特別是600M

3、機(jī)組對凝結(jié)水溶解氧含量有更高的要求.因為溶解氧大幅度超標(biāo)或長期不合格，會加速凝結(jié)水管道及設(shè)備的腐蝕，并使凝結(jié)水中含有氧化鐵離子，引起電化腐蝕，使傳熱惡化，直至發(fā)生鍋爐爆管，嚴(yán)重威脅機(jī)組安全、經(jīng)濟(jì)運行。,凝結(jié)水溶解氧存在的原因：,1.真空系統(tǒng)不嚴(yán)密，進(jìn)入凝結(jié)器的漏量大； 2.有溶解氧含量較高的補水或回收水大量進(jìn)入凝結(jié)器；,Condensate of dissolved oxygen reasons for the existence :,1.vacuum system is not tight ,a lot of air to enter the condenser ; 2.higher lev

4、els of dissolved oxygen replenish water or recycled water enter the condenser,針對上述原因，從以下方面進(jìn)行防范和處理：,For the above reasons , from the following aspects prevent and treatment :,運行中真空系統(tǒng)的查漏以氦介質(zhì)檢漏為主。方法是在運行真空泵出口布置氦介質(zhì)檢漏裝置，利用專用的噴槍在所有負(fù)壓系統(tǒng)的閥門、法蘭、管道焊縫、排大氣口等處噴氦氣，然后觀察1-2分鐘，如果檢測點有泄露，檢漏裝置就會發(fā)出報警，泄漏量越大，報警數(shù)值就越大，即使很微量的

5、泄露，也能檢測出來。并且這種方法靈活，不受時間限制，消除漏點后隨時可以檢測溶解氧的變化。缺點是工作量大，耗時長。,1.真空系統(tǒng)的查漏,1.vacuum system leak,running vacuum system leak is mainly helium medium Leak . running vacuum pump outlet layout the helium medium leak detection devices , with a dedicated gun spray helium to all negative pressure system valves, fla

6、nges , pipe welds and exclusive atmosphere mouth etc, then observed for 1-2 minutes , if it detects some leakage ,and the leak detection device will alarm , the greater the amount of leakage , the greater the alarm value , even a very small amount of leakage can be detected . the method is flexible

7、, without time limit , after eliminate the leak ，at any time the change of dissolved oxygen can be detected . The drawback is the large amount of work , time-consuming long,灌水查漏。方法是：凝結(jié)器灌水至末級葉片下100mm高度，然后查漏處理。需要注意的是灌水過程中有專人監(jiān)視水位，防止水位過高進(jìn)入汽輪機(jī)。但這種方法必須停機(jī)后才能進(jìn)行。,Condenser irrigation to the last stage blades

8、 under 100mm height , then leak to handle . Should be noted that there is someone to monitor the water level,in order to prevent the high water level enter the turbine in the irrigation process . However , this method must be shut down after .,The purpose of irrigation leak,2.凝結(jié)水泵系統(tǒng)的改造,Condensate pu

9、mp seal water instead of two : closed water and condensate pump outlet self-sealing water,凝結(jié)水泵密封水水源改為兩路：閉式水和凝結(jié)泵出口自密封水。 凝結(jié)水泵進(jìn)口濾網(wǎng)頂部增加排空氣管路,2.Condensate pump system transformation,Increase exhaust air line at the top of condensate pump inlet filter,3.對加入凝結(jié)水的回收水進(jìn)行處理,熱力系統(tǒng)內(nèi)漏進(jìn)入凝結(jié)器內(nèi)的非正常疏水。該疏水進(jìn)入凝結(jié)器導(dǎo)致熱負(fù)荷增加，汽阻

10、增大，造成凝結(jié)器內(nèi)空氣分壓的提高，從而凝結(jié)水的含氧量增加。因此查出閥門泄露并及時更換內(nèi)泄閥門是一項長期的工作,低加等熱力系統(tǒng)的正常疏水。方法是維持低加正常水位，防止無水位運行或常開危急疏水運行，另外加強(qiáng)對疏水系統(tǒng)閥門法蘭的檢漏，盡可能減少空氣的漏人,3 . Join condensate recycled water treatment,normal drain low pressure heater of thermal system . the method is to maintain the the low pressure heater normal level , to preve

11、nt the no level or long-time open a critical drain valve running , in addition to strengthening the valve flange leak detection of drain system , in order to minimize air leakage . the abnormal drain leakage of thermal system leak into condenser . the drain entering condenser that heat load increase

12、s, and the steam resistance increases, resulte to raise the branch pressure of air in the condenser , and raise the water oxygen content of condenser, therefore detect valve leaks and timely replacement the leaking valve is a long-standing work .,4凝補水系統(tǒng)的改造,凝補水是除鹽水。除鹽水的含氧量很高，需要進(jìn)行深度除氧。一般的說，凝補水直接補入熱井，沒

13、有利用凝結(jié)器的真空除氧作用，除鹽水補水口應(yīng)接在6.9米的7、8號低加側(cè)，經(jīng)充分霧化后增大凝補水與排汽的接觸面積，從而減少凝結(jié)水的含氧量。,4. Condensate replenishment system transformation,Condensate replenishment is demineralized water , the oxygen content of demineralizing water is very high , it need depth to remove oxygn . Condensate replenishment directly into th

14、e hot well , no make full use vacuum removalling oxygn role of condenser, replenishment point of demineralizing water should pick the 6.9 m 7,8 low pressure heater side , after fully atomized to increase contacting area of condensate replenishment with exhaust , thereby reduce the oxygen content of

15、the condensate .,案例分析:,上海吳涇發(fā)電有限責(zé)任公司2*300MW機(jī)組運行中凝結(jié)水溶解氧時有超標(biāo)(標(biāo)準(zhǔn)控制30ug/L),2010年12月份#1機(jī)組進(jìn)行B級檢修時發(fā)現(xiàn):給水泵、省煤器腐蝕嚴(yán)重，同時發(fā)現(xiàn)鍋爐內(nèi)部也有一定結(jié)垢和腐蝕。 經(jīng)過排查發(fā)現(xiàn):凝結(jié)泵自密封閥門開度小于10%時凝補水會進(jìn)入凝結(jié)水中，導(dǎo)致凝結(jié)水含氧量升高。 另外排查發(fā)現(xiàn):真空系統(tǒng)漏點多集中在凝結(jié)器管閥和凝結(jié)水泵入口管閥等處，空氣的漏入導(dǎo)致凝結(jié)水含氧量升高。 上述問題解決后凝結(jié)水溶解氧合格率達(dá)到100%，平均化驗值達(dá)到21ug/L.,Case Study:,Shanghai Wujing Power Company

16、 2 * 300MW unit :during operation it often can be find excessive by dissolved oxygen of condensate ( standard control 30ug / L). when # 1 unit B type overhaul : severe corrosion for the feed water pumps and economizer , at the same time find some scale and corrosion inside the boiler .,After investigation found :the condensate replenishment enter condensate when graduation of condensate Pump self - sealing valve is less than 10%, result to increase oxygen content of condensate,Another investigation found : vacuum system leakage points are more concentrated in the condenser