燃煤电(dian)厂一直是国(guo)家环(huan)(huan)境治理的(de)重点(dian)，新(xin)出(chu)台的(de)污(wu)染(ran)(ran)物排(pai)放(fang)标(biao)(biao)(biao)准更是对近年来陆续跟进的(de)除尘、脱(tuo)硫(liu)以及脱(tuo)硝系统提出(chu)了(le)更高的(de)要求，如何控制(zhi)PM2.5细颗粒(li)排(pai)放(fang)、石(shi)膏雨(yu)和(he)烟(yan)囱蓝(lan)烟(yan)等(deng)问题已(yi)成为当务之急。新(xin)的(de)《火电(dian)厂大气污(wu)染(ran)(ran)物排(pai)放(fang)标(biao)(biao)(biao)准》(GB13223-2011)中(zhong)，粉尘排(pai)放(fang)限(xian)值(zhi)由50mg/m3提高到30mg/m3，重点(dian)地区提高到20mg/m3，单(dan)纯(chun)的(de)干(gan)式(shi)电(dian)已(yi)经很难满足要求，同时新(xin)标(biao)(biao)(biao)准也提高了(le)NOx和(he)SOx的(de)排(pai)放(fang)限(xian)值(zhi)，并增(zeng)加了(le)Hg的(de)控制(zhi)指标(biao)(biao)(biao)。湿(shi)式(shi)电(dian)除尘器(WESP)在实现超低排(pai)放(fang)、控制(zhi)PM2.5和(he)重金属等(deng)复合(he)污(wu)染(ran)(ran)物方面应用效果良好，国(guo)家环(huan)(huan)保部在《环(huan)(huan)境空(kong)气细颗粒(li)物污(wu)染(ran)(ran)防治技术(shu)政策(试行(xing))》(征(zheng)求意见稿)中(zhong)明确指出(chu):鼓励火电(dian)企业(ye)采用湿(shi)式(shi)电(dian)除尘等(deng)新(xin)技术(shu)，防止脱(tuo)硫(liu)脱(tuo)硝造成的(de)“石(shi)膏雨(yu)”以及“蓝(lan)烟(yan)”污(wu)染(ran)(ran)。

2 国内外应用现状和技术特点

2.1 国内湿式电除(chu)尘(chen)器应用(yong)概况

  我国在湿(shi)式(shi)(shi)电(dian)除尘(chen)(chen)(chen)技术研(yan)(yan)究方面起步较晚，最早主要是硫酸和(he)冶金工业中(zhong)应(ying)用(yong)(yong)了一些中(zhong)小型的湿(shi)式(shi)(shi)电(dian)除尘(chen)(chen)(chen)器(qi)。从(cong)2009年开始，逐步开展了针对燃煤(mei)(mei)(mei)电(dian)厂(chang)应(ying)用(yong)(yong)湿(shi)式(shi)(shi)电(dian)除尘(chen)(chen)(chen)器(qi)的研(yan)(yan)究和(he)探(tan)索，并取得了多个项目的成功应(ying)用(yong)(yong)。华(hua)电(dian)淄博热电(dian)有(you)限公司湿(shi)式(shi)(shi)电(dian)除尘(chen)(chen)(chen)工程，该项目充分考虑了老厂(chang)炉后场地有(you)限的特点，采用(yong)(yong)了双(shuang)层(ceng)复(fu)式(shi)(shi)卧式(shi)(shi)结构，结构紧凑。鞍钢第二发电(dian)厂(chang)燃气-蒸汽联合循(xun)环机组(zu)，引(yin)进日本三菱湿(shi)式(shi)(shi)电(dian)除尘(chen)(chen)(chen)器(qi)装(zhuang)置(平板式(shi)(shi))，用(yong)(yong)于除尘(chen)(chen)(chen)净化进入煤(mei)(mei)(mei)气压缩(suo)机前高炉、焦炉煤(mei)(mei)(mei)气。

2.2 国外湿式(shi)电除(chu)尘器应用概况

   日本的湿(shi)(shi)式(shi)电(dian)(dian)除尘(chen)技术起步(bu)较早，已经(jing)有30多年的应(ying)用史，仅三菱重工(gong)就有33台套(tao)应(ying)用于电(dian)(dian)厂。日本碧南电(dian)(dian)厂5台套(tao)湿(shi)(shi)式(shi)电(dian)(dian)除尘(chen)器投产20年来，烟(yan)尘(chen)排放(fang)浓度长期(qi)保持在2～5mg/m3的水(shui)平(ping)，并且湿(shi)(shi)式(shi)电(dian)(dian)除尘(chen)器本体(ti)和内(nei)部构(gou)件均未发生(sheng)严(yan)重腐蚀(shi)。

   美国在(zai)湿式(shi)电除尘方面(mian)研究(jiu)也较早，与(yu)(yu)日本(ben)不(bu)(bu)同(tong)(tong)的(de)(de)(de)(de)是(shi)，美国应用(yong)较多的(de)(de)(de)(de)是(shi)垂直烟气流(liu)独(du)(du)立(li)设(she)(she)计和与(yu)(yu)WFGD的(de)(de)(de)(de)整体式(shi)设(she)(she)计。典型工程有AES深水(shui)电厂(chang)，采用(yong)的(de)(de)(de)(de)是(shi)吸收(shou)塔后单独(du)(du)布(bu)(bu)(bu)置(zhi)的(de)(de)(de)(de)垂直烟气流(liu)设(she)(she)计。整体式(shi)布(bu)(bu)(bu)置(zhi)方案具(ju)有不(bu)(bu)用(yong)另外占用(yong)场地，减少了(le)内部连(lian)接管道和土建，无(wu)单独(du)(du)支架(jia)，管道布(bu)(bu)(bu)置(zhi)简单，投建成本(ben)和运行(xing)费用(yong)低的(de)(de)(de)(de)优(you)点。缺点是(shi):由于布(bu)(bu)(bu)置(zhi)在(zai)WFGD的(de)(de)(de)(de)上(shang)方，使得(de)烟气的(de)(de)(de)(de)流(liu)动阻力增(zeng)加(jia)，同(tong)(tong)时高空(kong)布(bu)(bu)(bu)置(zhi)也使得(de)基础和钢结(jie)构(gou)负荷增(zeng)加(jia)。

3 的原理及特点

3.1 工作原理

   湿(shi)(shi)式(shi)电(dian)(dian)(dian)(dian)除(chu)尘(chen)(chen)器(qi)的工作原理和干(gan)式(shi)的类似，都是高(gao)压电(dian)(dian)(dian)(dian)晕放电(dian)(dian)(dian)(dian)使粉(fen)尘(chen)(chen)或水雾荷(he)电(dian)(dian)(dian)(dian)，荷(he)电(dian)(dian)(dian)(dian)的粒子在(zai)(zai)电(dian)(dian)(dian)(dian)场力的作用下到(dao)达集尘(chen)(chen)板，但在(zai)(zai)粉(fen)尘(chen)(chen)的清除(chu)方式(shi)上，干(gan)式(shi)电(dian)(dian)(dian)(dian)除(chu)尘(chen)(chen)器(qi)采用的是机械(xie)振(zhen)打(da)，而湿(shi)(shi)式(shi)电(dian)(dian)(dian)(dian)除(chu)尘(chen)(chen)器(qi)采用冲(chong)刷液冲(chong)洗电(dian)(dian)(dian)(dian)极(ji)，将收尘(chen)(chen)板上捕获的粉(fen)尘(chen)(chen)冲(chong)刷到(dao)灰(hui)斗(dou)中随之排出。

3.2 结构特点

   (1)本体结构。湿式(shi)(shi)电(dian)(dian)(dian)除尘(chen)(chen)器主要由进(jin)出口烟道、除尘(chen)(chen)器壳(qiao)体、导流板、整流格栅、阳极(ji)收尘(chen)(chen)板阴(yin)极(ji)线、绝缘(yuan)箱、冲洗(xi)水系(xi)统(tong)、电(dian)(dian)(dian)源及控制系(xi)统(tong)组成(cheng)。结构类型上一(yi)(yi)般分(fen)为(wei)(wei)板式(shi)(shi)和管(guan)式(shi)(shi)两类，板式(shi)(shi)的(de)(de)(de)集(ji)(ji)尘(chen)(chen)极(ji)为(wei)(wei)平(ping)板状(zhuang)，水膜形成(cheng)性(xing)好(hao)，极(ji)板间(jian)均布(bu)电(dian)(dian)(dian)晕线，主体类似于(yu)干式(shi)(shi)电(dian)(dian)(dian)除尘(chen)(chen)器，能处理水平(ping)或垂直流动(dong)的(de)(de)(de)烟气(qi);管(guan)式(shi)(shi)的(de)(de)(de)集(ji)(ji)尘(chen)(chen)极(ji)一(yi)(yi)般为(wei)(wei)多根(gen)并(bing)列的(de)(de)(de)圆形或多边形金属管(guan)，中间(jian)分(fen)布(bu)电(dian)(dian)(dian)晕线，只(zhi)能处理垂直流动(dong)的(de)(de)(de)烟气(qi)。湿式(shi)(shi)电(dian)(dian)(dian)除尘(chen)(chen)器外(wai)(wai)部构件采用普通碳素钢，内表面加涂层以防腐蚀(shi)，安(an)装时要注意控制内表面的(de)(de)(de)破损，特别是焊(han)接点、构件连接处等。外(wai)(wai)壳(qiao)的(de)(de)(de)外(wai)(wai)部不(bu)需(xu)要保温(wen)，因为(wei)(wei)烟气(qi)温(wen)度低于(yu)饱和温(wen)度，因而(er)外(wai)(wai)壳(qiao)处的(de)(de)(de)烟气(qi)也(ye)几乎(hu)没有降温(wen)。总体来看(kan)，管(guan)式(shi)(shi)集(ji)(ji)尘(chen)(chen)极(ji)要比板式(shi)(shi)的(de)(de)(de)效率(lv)高、便于(yu)布(bu)置且占用空(kong)间(jian)少。

    (2)清灰方(fang)式(shi)(shi)。干式(shi)(shi)电除(chu)尘(chen)(chen)(chen)器(qi)是通过振打(da)的方(fang)式(shi)(shi)，将集尘(chen)(chen)(chen)极上(shang)的积灰振落(luo)到(dao)灰斗，而湿式(shi)(shi)电除(chu)尘(chen)(chen)(chen)器(qi)是将冲(chong)(chong)(chong)刷(shua)(shua)液喷淋至集尘(chen)(chen)(chen)板上(shang)形成连续的液膜，随(sui)着冲(chong)(chong)(chong)刷(shua)(shua)液的流动将粉尘(chen)(chen)(chen)冲(chong)(chong)(chong)刷(shua)(shua)到(dao)灰斗中随(sui)之排出(chu)。若集尘(chen)(chen)(chen)极上(shang)的粉尘(chen)(chen)(chen)不能及时冲(chong)(chong)(chong)刷(shua)(shua)下(xia)来，会产生运行电压(ya)下(xia)降、电晕封闭和局部腐蚀等问(wen)题(ti)。常(chang)见的清灰方(fang)式(shi)(shi)包括自冲(chong)(chong)(chong)刷(shua)(shua)、喷雾冲(chong)(chong)(chong)刷(shua)(shua)和液膜冲(chong)(chong)(chong)刷(shua)(shua)。不管哪类(lei)冲(chong)(chong)(chong)刷(shua)(shua)方(fang)式(shi)(shi)，冲(chong)(chong)(chong)刷(shua)(shua)液中含有的大(da)量悬浮(fu)颗粒物以及酸性(xing)物质，直(zhi)接排放会造(zao)成二次污染和水(shui)资源的浪费(fei)，因此需要解决灰水(shui)循环(huan)和水(shui)耗问(wen)题(ti)建议对冲(chong)(chong)(chong)洗水(shui)采用(yong)闭式(shi)(shi)循环(huan)。

3.3 湿式电除尘器的优缺点

  湿式电(dian)除尘(chen)(chen)器的(de)优点(dian):对粉(fen)尘(chen)(chen)的(de)适(shi)应(ying)能(neng)力强，能(neng)达到(dao)很高(gao)(gao)(gao)的(de)除尘(chen)(chen)效(xiao)率，同时也适(shi)用(yong)于处理高(gao)(gao)(gao)温(wen)、高(gao)(gao)(gao)湿的(de)烟(yan)气(qi);没有(you)二(er)次扬尘(chen)(chen);没有(you)锤击设备(bei)等(deng)易损部(bu)件，可靠(kao)性高(gao)(gao)(gao);能(neng)有(you)效(xiao)去除亚微米级颗粒(li)、SO3气(qi)溶胶和(he)石膏(gao)微液滴，对控制PM2.5、蓝烟(yan)和(he)石膏(gao)雨效(xiao)果(guo)良好(hao);由于在(zai)电(dian)除尘(chen)(chen)器内电(dian)场(chang)气(qi)流(liu)速度(du)较(jiao)高(gao)(gao)(gao)，灰斗的(de)倾斜(xie)角减小，设备(bei)的(de)布置紧(jin)凑;降低烟(yan)气(qi)中总的(de)携带水(shui)(shui)量，减小石膏(gao)雨形(xing)成的(de)几(ji)率存(cun)在(zai)的(de)问题(ti):排烟(yan)温(wen)度(du)需低于冲刷液的(de)绝热(re)饱和(he)温(wen)度(du);在(zai)高(gao)(gao)(gao)粉(fen)尘(chen)(chen)浓(nong)度(du)和(he)高(gao)(gao)(gao)SO2浓(nong)度(du)时难以采用(yong)湿式电(dian)除尘(chen)(chen)器;必(bi)须要(yao)有(you)良好(hao)的(de)防腐蚀(shi)措施;湿式电(dian)除尘(chen)(chen)器冲洗(xi)水(shui)(shui)虽采用(yong)闭(bi)式循环(huan)，但要(yao)与(yu)脱硫(liu)水(shui)(shui)系统保(bao)持平(ping)衡(heng);多处部(bu)件需要(yao)用(yong)耐腐蚀(shi)材料，且未大规模生产(chan)，单个产(chan)品投入(ru)成本较(jiao)高(gao)(gao)(gao);新机组需单独(du)占(zhan)用(yong)炉后场(chang)地，对老机组改(gai)造将(jiang)会(hui)有(you)场(chang)地布置问题(ti)。

4 新技术发展状况

   (1)湿式(shi)膜电(dian)除尘(chen)(chen)(chen)技术(shu)。该技术(shu)最早在1979年，由美国俄亥(hai)俄大学Pasic提出并(bing)研(yan)究(jiu)成功[11]。湿式(shi)膜电(dian)除尘(chen)(chen)(chen)器采用(yong)(yong)碳纤维(wei)或(huo)硅纤维(wei)编织膜作(zuo)为(wei)集尘(chen)(chen)(chen)极(ji)(ji)，代替(ti)传统电(dian)除尘(chen)(chen)(chen)器中的金属(shu)集尘(chen)(chen)(chen)极(ji)(ji)，利(li)用(yong)(yong)毛(mao)细作(zuo)用(yong)(yong)，使水均匀的分布在膜表(biao)面，消除了传统湿式(shi)电(dian)除尘(chen)(chen)(chen)器集尘(chen)(chen)(chen)板上容易出现的局部干燥区，避免反(fan)电(dian)晕的产生，也保证了电(dian)场的稳定，提高了除尘(chen)(chen)(chen)效率(lv)。

    (2)干湿复合(he)电(dian)(dian)除(chu)(chu)尘技(ji)术。集合(he)了干式和湿式电(dian)(dian)的优点，采(cai)用前级电(dian)(dian)场(chang)干式电(dian)(dian)除(chu)(chu)尘+末极电(dian)(dian)场(chang)湿式电(dian)(dian)除(chu)(chu)尘的配套方案，最早由美国电(dian)(dian)研所于20世纪90年代开始研究。

5 湿式电除(chu)尘(chen)器与现有除(chu)尘(chen)设备比较

   以100MW机组为例，达(da)到国家(jia)排放标准，对(dui)采用(yong)5电场干(gan)式(shi)电除(chu)尘器(qi)、袋(dai)式(shi)除(chu)尘器(qi)、电袋(dai)复合(he)式(shi)除(chu)尘器(qi)(包含2电场)、4干(gan)式(shi)+1湿式(shi)电除(chu)尘器(qi)，进行技术性(xing)、经(jing)济(ji)性(xing)比较。

5.1 经济性比较

(1)设备费用(yong)。袋(dai)式(shi)除(chu)尘器(qi)(qi)<5电场干式(shi)除(chu)尘器(qi)(qi)<电袋(dai)复合式(shi)除(chu)尘器(qi)(qi)<4干式(shi)+1湿式(shi)电除(chu)尘器(qi)(qi);

(2)土建及(ji)施工费用。袋式除(chu)尘(chen)(chen)(chen)器<电袋复合式除(chu)尘(chen)(chen)(chen)器<5电场(chang)干式除(chu)尘(chen)(chen)(chen)器<4干式+1湿式电除(chu)尘(chen)(chen)(chen)器;

(3)年运行、维护费用。5电场干(gan)式(shi)(shi)(shi)除(chu)(chu)尘(chen)器(qi)(qi)<电袋复合式(shi)(shi)(shi)除(chu)(chu)尘(chen)器(qi)(qi)<4干(gan)式(shi)(shi)(shi)+1湿式(shi)(shi)(shi)电除(chu)(chu)尘(chen)器(qi)(qi)<袋式(shi)(shi)(shi)除(chu)(chu)尘(chen)器(qi)(qi);

(4)总费用(yong)。5电(dian)场干式(shi)(shi)除尘器(qi)<袋(dai)式(shi)(shi)除尘器(qi)<电(dian)袋(dai)式(shi)(shi)复合除尘器(qi)<4干式(shi)(shi)+1湿(shi)(shi)式(shi)(shi)电(dian)除尘器(qi)。 由(you)此可见，湿(shi)(shi)式(shi)(shi)电(dian)除器(qi)的总费用(yong)最高(gao)，但其所带来(lai)的社会效益和(he)环境效益是无法估量的。

5.2 技术性比较

   现(xian)在广(guang)泛采用(yong)的(de)干(gan)式(shi)电除(chu)(chu)(chu)(chu)尘(chen)、袋(dai)式(shi)除(chu)(chu)(chu)(chu)尘(chen)、电袋(dai)复(fu)合式(shi)除(chu)(chu)(chu)(chu)尘(chen)技术，仅能控制(zhi)脱(tuo)硫(liu)塔前的(de)粉尘(chen)排放(fang)浓(nong)度(du)，对(dui)(dui)于SCR以及WFGD后所(suo)产生的(de)SO3气溶(rong)胶和石膏微液滴没有去除(chu)(chu)(chu)(chu)效(xiao)果，对(dui)(dui)于PM2.5细微颗粒物(wu)(wu)(wu)(wu)和重金(jin)属污(wu)染(ran)物(wu)(wu)(wu)(wu)的(de)去除(chu)(chu)(chu)(chu)效(xiao)果也很有限(xian)。干(gan)式(shi)电除(chu)(chu)(chu)(chu)尘(chen)器(qi)(qi)除(chu)(chu)(chu)(chu)尘(chen)性能受(shou)(shou)(shou)煤(mei)质(zhi)(zhi)、飞灰(hui)成分、物(wu)(wu)(wu)(wu)相组(zu)成影响;袋(dai)式(shi)除(chu)(chu)(chu)(chu)尘(chen)器(qi)(qi)不受(shou)(shou)(shou)煤(mei)质(zhi)(zhi)、飞灰(hui)特性影响，但(dan)对(dui)(dui)烟(yan)气温度(du)、湿(shi)(shi)度(du)、成分敏;感(gan)电袋(dai)复(fu)合式(shi)除(chu)(chu)(chu)(chu)尘(chen)器(qi)(qi)不受(shou)(shou)(shou)煤(mei)质(zhi)(zhi)、飞灰(hui)特性影响，同样对(dui)(dui)烟(yan)气温度(du)、湿(shi)(shi)度(du)等敏感(gan)，但(dan)要好于袋(dai)式(shi)除(chu)(chu)(chu)(chu)尘(chen)器(qi)(qi);湿(shi)(shi)式(shi)电除(chu)(chu)(chu)(chu)尘(chen)器(qi)(qi)不受(shou)(shou)(shou)煤(mei)质(zhi)(zhi)、烟(yan)气工况影响，适用(yong)范(fan)围较广(guang)。湿(shi)(shi)式(shi)电除(chu)(chu)(chu)(chu)尘(chen)器(qi)(qi)作(zuo)为大(da)气复(fu)合污(wu)染(ran)物(wu)(wu)(wu)(wu)的(de)终端控制(zhi)设(she)备(bei)，在控制(zhi)上述(shu)污(wu)染(ran)物(wu)(wu)(wu)(wu)满足新标准烟(yan)尘(chen)排放(fang)要求上都有出色(se)的(de)表现(xian)。表1列出了上述(shu)几种(zhong)除(chu)(chu)(chu)(chu)尘(chen)技术比较。

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