<一>、燃煤火力發電中的靜電除塵技術

濕式靜電除塵(chen)器是(shi)在接有(you)直流高(gao)壓電的陰極(ji)與陽(yang)極(ji)板之間電場通(tong)過煙塵(chen)氣體(ti)，電離煙塵(chen)氣體(ti)。負(fu)電氣體(ti)離子向(xiang)陽(yang)板運動過程中與煙塵(chen)結合使其帶負(fu)電向(xiang)陽(yang)極(ji)運動并沉積(ji)于(yu)陽(yang)極(ji)板上(shang)。

可(ke)控(kong)(kong)硅(gui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)是(shi)比(bi)較傳統(tong)的(de)(de)(de)(de)靜電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)除(chu)塵(chen)(chen)(chen)方(fang)式，通(tong)過(guo)變壓(ya)器將工(gong)頻(pin)(pin)(pin)交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)升壓(ya)然后(hou)半(ban)控(kong)(kong)整流(liu)(liu)(liu)，這種方(fang)式輸出(chu)脈動較大(da)，由于(yu)輸出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)的(de)(de)(de)(de)峰(feng)值不(bu)能高(gao)(gao)(gao)(gao)于(yu)擊穿(chuan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，所(suo)以輸出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)平(ping)均(jun)值比(bi)擊穿(chuan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)低。隨著全控(kong)(kong)型(xing)功率器件的(de)(de)(de)(de)發展，尤其是(shi)高(gao)(gao)(gao)(gao)壓(ya)大(da)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)的(de)(de)(de)(de)IGBT發展，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)除(chu)塵(chen)(chen)(chen)器高(gao)(gao)(gao)(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)發展，成為(wei)具有(you)(you)新一(yi)代優異(yi)性(xing)能的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)除(chu)塵(chen)(chen)(chen)器供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)裝置(zhi)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)除(chu)塵(chen)(chen)(chen)器高(gao)(gao)(gao)(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)采(cai)用逆(ni)變方(fang)式，可(ke)提供(gong)脈沖寬度(du)為(wei)微(wei)秒級(ji)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)脈沖給電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)除(chu)塵(chen)(chen)(chen)器供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，是(shi)開關(guan)頻(pin)(pin)(pin)率高(gao)(gao)(gao)(gao)輸出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)脈動小的(de)(de)(de)(de)直流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，輸出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)平(ping)均(jun)值高(gao)(gao)(gao)(gao)于(yu)可(ke)控(kong)(kong)硅(gui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)，具有(you)(you)很(hen)(hen)大(da)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)場強度(du)，很(hen)(hen)高(gao)(gao)(gao)(gao)的(de)(de)(de)(de)粒(li)子荷電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)和很(hen)(hen)高(gao)(gao)(gao)(gao)的(de)(de)(de)(de)除(chu)塵(chen)(chen)(chen)效率，可(ke)減(jian)少煙塵(chen)(chen)(chen)排放40%~70%，并且可(ke)減(jian)少電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)除(chu)塵(chen)(chen)(chen)器供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)功率50%~80%。高(gao)(gao)(gao)(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)火花控(kong)(kong)制特(te)性(xing)好，在火花放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)嚴(yan)重(zhong)的(de)(de)(de)(de)場合，可(ke)控(kong)(kong)硅(gui)為(wei)半(ban)控(kong)(kong)功率器件，會縮小其導通(tong)角，使得電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)輸出(chu)功率下降，而高(gao)(gao)(gao)(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)在幾個開關(guan)周期內(nei)能恢復供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，了輸出(chu)功率。另外，高(gao)(gao)(gao)(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)根據電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)除(chu)塵(chen)(chen)(chen)器的(de)(de)(de)(de)工(gong)況可(ke)提供(gong)較為(wei)合適的(de)(de)(de)(de)輸出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)；高(gao)(gao)(gao)(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)效率通(tong)常能達(da)到90%以上(shang)；高(gao)(gao)(gao)(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)由于(yu)采(cai)用高(gao)(gao)(gao)(gao)頻(pin)(pin)(pin)變壓(ya)器，具有(you)(you)體積(ji)小重(zhong)量(liang)輕的(de)(de)(de)(de)特(te)點，可(ke)高(gao)(gao)(gao)(gao)度(du)集成，重(zhong)量(liang)僅(jin)為(wei)工(gong)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)1/4；高(gao)(gao)(gao)(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)輔助設備少，安(an)裝方(fang)便，節省了費(fei)用；高(gao)(gao)(gao)(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)采(cai)用三相(xiang)交(jiao)流(liu)(liu)(liu)供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，無缺相(xiang)損耗(hao)，對電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)網影(ying)響小。高(gao)(gao)(gao)(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)目前有(you)(you)兩(liang)種形式，一(yi)種是(shi)PWM關(guan)高(gao)(gao)(gao)(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)，一(yi)種使用串(chuan)聯(lian)諧(xie)振(zhen)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路實現軟開關(guan)的(de)(de)(de)(de)高(gao)(gao)(gao)(gao)頻(pin)(pin)(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)。

串聯諧(xie)(xie)振(zhen)(zhen)高頻電(dian)(dian)源(yuan)是(shi)將(jiang)PWM移相控(kong)制(zhi)(zhi)與諧(xie)(xie)振(zhen)(zhen)變(bian)換(huan)控(kong)制(zhi)(zhi)相結合，通(tong)過(guo)(guo)兩橋臂之(zhi)間移相角的(de)(de)控(kong)制(zhi)(zhi)來調節輸出(chu)電(dian)(dian)壓(ya)，通(tong)過(guo)(guo)恒(heng)頻控(kong)制(zhi)(zhi)實(shi)現功率開(kai)關(guan)管的(de)(de)零電(dian)(dian)壓(ya)零電(dian)(dian)流軟開(kai)關(guan)，減小了開(kai)關(guan)損(sun)耗和噪聲干擾，實(shi)現較高的(de)(de)開(kai)關(guan)頻率，并(bing)(bing)具有類似恒(heng)流源(yuan)的(de)(de)特性，能(neng)除(chu)塵電(dian)(dian)場火(huo)花(hua)的(de)(de)大電(dian)(dian)流沖擊，并(bing)(bing)熄滅火(huo)花(hua)并(bing)(bing)恢復電(dian)(dian)場的(de)(de)能(neng)量。

<二>、影響(xiang)電除(chu)塵器除(chu)塵效(xiao)率的四(si)類主要(yao)因素(su)

影響(xiang)靜電除塵器配件性能的因素很多，可(ke)以大致歸納為如下(xia)四大類：

1、粉(fen)塵(chen)特性，主要包括粉(fen)塵(chen)的粒徑分布，真密(mi)度和(he)堆積密(mi)度，粘附性和(he)比電阻等。

2、煙氣(qi)性質，主要(yao)包括煙氣(qi)溫度(du)、壓(ya)力、成分、濕度(du)、流速和含(han)塵濃度(du)等。

3、結構因素，包括(kuo)電暈(yun)線的幾何形狀、直徑、數(shu)(shu)量和線間(jian)距(ju)，收塵(chen)極(ji)(ji)的形式，極(ji)(ji)板(ban)斷(duan)面(mian)形狀、極(ji)(ji)板(ban)間(jian)距(ju)、極(ji)(ji)板(ban)面(mian)積以及(ji)電場數(shu)(shu)、電場長度(du)，供電方式，振打方式(方向、強度(du)、周(zhou)期)，氣流分布裝(zhuang)置(zhi)，外殼(ke)嚴密程度(du)，灰(hui)斗形式和出(chu)灰(hui)口鎖(suo)風(feng)裝(zhuang)置(zhi)等(deng)。

4、操作因素(su)，包括(kuo)伏一安特性、漏風率、氣流短(duan)路、粉塵二次(ci)飛揚和電暈線肥大等(deng)。

特(te)(te)別是粉塵和煙(yan)氣的特(te)(te)性(xing)(xing)，對(dui)電收(shou)塵的性(xing)(xing)能(neng)影響尤為顯著(zhu)。因(yin)(yin)(yin)煙(yan)塵發生(sheng)裝置的類型、構造、原料、燃料的種(zhong)類、混合比、燃燒方式(shi)以及其它條(tiao)件的不同而有(you)顯著(zhu)的變(bian)化(hua)。因(yin)(yin)(yin)此，電除塵裝置與其它除塵裝置一樣，即使有(you)良好的收(shou)塵性(xing)(xing)能(neng)，但是由于外界條(tiao)件的變(bian)化(hua)，也會往往達不到預期的效(xiao)果。而且電除塵對(dui)外界條(tiao)件的變(bian)化(hua)較其它除塵裝置很為敏感。所以在設(she)計或選用電除塵器(qi)之前應充分掌握影響電除塵器(qi)性(xing)(xing)能(neng)的諸因(yin)(yin)(yin)素。

在現場運行(xing)經驗中，高比(bi)電阻(zu)粉塵(chen)(chen)反(fan)電暈和粉塵(chen)(chen)二次飛揚是影響電除塵(chen)(chen)器除塵(chen)(chen)效率的主要因(yin)素。