一、電除塵器的除塵效率一般是多少
電除塵器是火力發電廠必備的配套設備，用于將燃煤或燃油鍋爐排放煙氣中的顆粒煙塵加以清除，從而大幅度降低排入大氣層中的煙塵量，它的除塵效率是選型的重要因素之一，那么電除塵器的除(chu)塵效(xiao)率(lv)是(shi)多少呢？
電(dian)除塵(chen)(chen)器的除塵(chen)(chen)效(xiao)(xiao)(xiao)率是(shi)比較(jiao)高的，因(yin)為它可以(yi)通過加長電(dian)場(chang)長度、增大電(dian)場(chang)有效(xiao)(xiao)(xiao)通流面積、改(gai)進控制(zhi)器的控制(zhi)質量、對煙氣進行調質等(deng)手段來(lai)提(ti)高除塵(chen)(chen)效(xiao)(xiao)(xiao)率。普通的電(dian)除塵(chen)(chen)器，其除塵(chen)(chen)效(xiao)(xiao)(xiao)率一般為99%，能夠(gou)鋪集(ji)0.01微(wei)米以(yi)上的細(xi)粒(li)粉塵(chen)(chen)。
二、影響電除塵器除塵效率的因素有哪些
電除塵(chen)器的(de)(de)除塵(chen)效(xiao)率很高，但在(zai)實際運行過程中，可能因為一(yi)些原(yuan)因導(dao)致除塵(chen)效(xiao)率達不到(dao)要求，影響電除塵(chen)器效(xiao)率的(de)(de)因素主要有：
1、高低壓供電控制裝置設計運行不佳
電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)除塵(chen)器(qi)(qi)直(zhi)流(liu)(liu)(liu)高(gao)壓由380V交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)經可控(kong)(kong)(kong)(kong)硅高(gao)壓整流(liu)(liu)(liu)設(she)(she)備(bei)供(gong)(gong)給(gei)，除塵(chen)器(qi)(qi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)場(chang)阻抗(kang)對高(gao)壓供(gong)(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)裝置(zhi)來說是一個變(bian)化的(de)(de)(de)(de)負載(zai)。當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)場(chang)阻抗(kang)升(sheng)高(gao)、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)變(bian)小(xiao)時(shi)，要(yao)求設(she)(she)備(bei)能(neng)(neng)自(zi)(zi)動升(sheng)壓；而當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)場(chang)阻抗(kang)降低、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)變(bian)大時(shi)，要(yao)求設(she)(she)備(bei)能(neng)(neng)自(zi)(zi)動降壓以保持設(she)(she)定的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)。整流(liu)(liu)(liu)變(bian)壓器(qi)(qi)內部的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)取樣電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻，引(yin)進負反饋信(xin)號，經微(wei)機智(zhi)能(neng)(neng)處理后移相(xiang)控(kong)(kong)(kong)(kong)制(zhi)可控(kong)(kong)(kong)(kong)硅的(de)(de)(de)(de)導通角(jiao)，改變(bian)負載(zai)輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓，達(da)到穩定輸(shu)出(chu)的(de)(de)(de)(de)目的(de)(de)(de)(de)，使電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)場(chang)獲得最有效(xiao)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)暈(yun)功(gong)率。然而有些電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)及控(kong)(kong)(kong)(kong)制(zhi)設(she)(she)備(bei)制(zhi)造廠(chang)生產(chan)的(de)(de)(de)(de)控(kong)(kong)(kong)(kong)制(zhi)器(qi)(qi)對設(she)(she)備(bei)控(kong)(kong)(kong)(kong)制(zhi)特性和(he)控(kong)(kong)(kong)(kong)制(zhi)方(fang)式、保護功(gong)能(neng)(neng)等還不完善(shan)，再加上電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)廠(chang)運(yun)行和(he)檢修人(ren)員對設(she)(she)備(bei)原理的(de)(de)(de)(de)理解存在一定的(de)(de)(de)(de)盲區，從而造成供(gong)(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)(kong)(kong)制(zhi)裝置(zhi)運(yun)行不佳。
2、振打清灰裝置的運行方式不合理
電除塵器(qi)一般(ban)使用振(zhen)打(da)方(fang)式清灰，在振(zhen)打(da)力度和均(jun)勻性都滿足要求(qiu)的情況下，振(zhen)打(da)制度（周期、時間、方(fang)式）是否合(he)理對(dui)電除塵器(qi)除塵效率影響極(ji)大。
振(zhen)打(da)周(zhou)期過長(chang)、極板(ban)積灰(hui)過厚，將降(jiang)低帶電粉塵(chen)(chen)(chen)在極板(ban)上的導電性能，降(jiang)低除(chu)(chu)塵(chen)(chen)(chen)效率；振(zhen)打(da)周(zhou)期過短，粉塵(chen)(chen)(chen)會分散成碎(sui)粉落下，引(yin)起較大的二次(ci)揚塵(chen)(chen)(chen)，即沉(chen)積在電除(chu)(chu)塵(chen)(chen)(chen)器收塵(chen)(chen)(chen)極上的粉塵(chen)(chen)(chen)再次(ci)被氣(qi)流帶出除(chu)(chu)塵(chen)(chen)(chen)器，尤其(qi)是(shi)末極電場(chang)的二次(ci)揚塵(chen)(chen)(chen)會大大降(jiang)低電除(chu)(chu)塵(chen)(chen)(chen)器的效率。
導致(zhi)二次(ci)揚(yang)塵(chen)(chen)的(de)因素有(you)許(xu)多，如粉(fen)塵(chen)(chen)的(de)比電(dian)(dian)(dian)阻(zu)過(guo)(guo)高(gao)，產(chan)生(sheng)反電(dian)(dian)(dian)暈收(shou)塵(chen)(chen)電(dian)(dian)(dian)場的(de)煙氣流速(su)(su)分布不(bu)(bu)均(jun)或流速(su)(su)過(guo)(guo)高(gao)而(er)(er)產(chan)生(sheng)的(de)紊流和渦流。因此，要求電(dian)(dian)(dian)場的(de)煙氣流速(su)(su)不(bu)(bu)超過(guo)(guo)3m/s，一般(ban)電(dian)(dian)(dian)場中運(yun)行的(de)煙氣流速(su)(su)都(dou)在1.5m/s左右，且盡(jin)可能(neng)使(shi)煙氣流分布均(jun)勻，而(er)(er)振打(da)清(qing)灰過(guo)(guo)頻，是(shi)造成(cheng)除塵(chen)(chen)器二次(ci)揚(yang)塵(chen)(chen)最(zui)主要的(de)因素。遵(zun)循一定(ding)的(de)程序，采用恰當的(de)試驗方法，建(jian)立正確的(de)振打(da)制度，同時加強對灰斗排灰設備的(de)維護(hu)，防止(zhi)灰斗出(chu)灰口堵塞(sai)，都(dou)能(neng)防止(zhi)二次(ci)揚(yang)塵(chen)(chen)的(de)發生(sheng)。
3、運行參數偏離正常值
在正常負荷下，工廠的煙氣流量、排煙溫度、煙氣含塵濃度等參數值與電除塵器設計的參數相差不大，電除塵器都能正常運行。若煙氣流量增大、排煙溫度升高、煙氣含塵濃度增加，電除塵器的運(yun)行工況就會惡化(hua)，使除塵效率降低。
4、煤種的變化
如(ru)果(guo)鍋爐(lu)燃(ran)燒煤種(zhong)(zhong)發(fa)生了變化，其(qi)熱(re)值(zhi)較(jiao)設計煤種(zhong)(zhong)低(di)(di)，灰(hui)分較(jiao)設計煤種(zhong)(zhong)高(gao)，則會(hui)(hui)(hui)加(jia)大對(dui)輸煤、制粉(fen)、除(chu)(chu)塵(chen)、輸灰(hui)設備的磨(mo)損，縮短設備的檢修(xiu)周(zhou)期(qi)。使用(yong)低(di)(di)熱(re)值(zhi)燃(ran)煤，會(hui)(hui)(hui)使鍋爐(lu)實(shi)際燃(ran)煤量增加(jia)，使煙氣(qi)(qi)的含(han)灰(hui)量增大。這樣會(hui)(hui)(hui)使電除(chu)(chu)塵(chen)器處理(li)煙氣(qi)(qi)含(han)塵(chen)濃度(du)超(chao)過設計值(zhi)，除(chu)(chu)塵(chen)效率將受(shou)到(dao)嚴重影響。
