1 系統組成及功能

1.1 系統組成

CEMS 是煙氣(qi)在線連(lian)續監測(ce)系(xi)(xi)(xi)統(tong)的(de)簡稱，是一種大型的(de)在線分析(xi)成套系(xi)(xi)(xi)統(tong)。CEMS 系(xi)(xi)(xi)統(tong)主要由(you)顆粒物(wu)監測(ce)子(zi)(zi)系(xi)(xi)(xi)統(tong)、氣(qi)態污染物(wu)監測(ce)子(zi)(zi)系(xi)(xi)(xi)統(tong)、煙氣(qi)排(pai)放參數(shu)監測(ce)子(zi)(zi)系(xi)(xi)(xi)統(tong)、系(xi)(xi)(xi)統(tong)控制及(ji)數(shu)據(ju)采集(ji)處理(li)子(zi)(zi)系(xi)(xi)(xi)統(tong)、氣(qi)源電源通訊等(deng)(deng)輔助設施(shi)子(zi)(zi)系(xi)(xi)(xi)統(tong)等(deng)(deng)組成。

1.2 主要功能

顆粒物監測子(zi)系統(tong)主(zhu)要對(dui)煙(yan)(yan)(yan)氣(qi)(qi)中的(de)(de)煙(yan)(yan)(yan)塵濁度(du)(du)(du)進(jin)行(xing)(xing)監測，并通(tong)(tong)過(guo)(guo)試(shi)驗標定轉(zhuan)(zhuan)換為煙(yan)(yan)(yan)氣(qi)(qi)濃(nong)(nong)度(du)(du)(du)參數(shu)(shu)(shu)。氣(qi)(qi)態(tai)污染物監測子(zi)系統(tong)主(zhu)要對(dui)煙(yan)(yan)(yan)氣(qi)(qi)中SO2、NOx、CO、CO2的(de)(de)濃(nong)(nong)度(du)(du)(du)進(jin)行(xing)(xing)監測，常見(jian)的(de)(de)分析原(yuan)理(li)為紅外吸收法(fa)（或紫外吸收法(fa)）。煙(yan)(yan)(yan)氣(qi)(qi)排放參數(shu)(shu)(shu)監測子(zi)系統(tong)主(zhu)要測試(shi)煙(yan)(yan)(yan)氣(qi)(qi)溫(wen)度(du)(du)(du)、流(liu)速、壓力、濕度(du)(du)(du)、氧(yang)量(liang)等(deng)(deng)參數(shu)(shu)(shu)，通(tong)(tong)過(guo)(guo)流(liu)速可(ke)以得出煙(yan)(yan)(yan)氣(qi)(qi)流(liu)量(liang)，同時(shi)根據煙(yan)(yan)(yan)氣(qi)(qi)溫(wen)度(du)(du)(du)、壓力、濕度(du)(du)(du)得出標準干煙(yan)(yan)(yan)氣(qi)(qi)量(liang)，通(tong)(tong)過(guo)(guo)氧(yang)量(liang)將濃(nong)(nong)度(du)(du)(du)換算(suan)為規定過(guo)(guo)剩空氣(qi)(qi)系數(shu)(shu)(shu)下的(de)(de)濃(nong)(nong)度(du)(du)(du)。系統(tong)控(kong)制子(zi)系統(tong)主(zhu)要對(dui)反(fan)吹、采(cai)樣進(jin)行(xing)(xing)控(kong)制，數(shu)(shu)(shu)據采(cai)集處理(li)子(zi)系統(tong)對(dui)信(xin)號采(cai)集、進(jin)行(xing)(xing)數(shu)(shu)(shu)據處理(li)并生成報表等(deng)(deng)。氣(qi)(qi)源為系統(tong)提供反(fan)吹氣(qi)(qi)體，電(dian)源為系統(tong)提供相(xiang)應電(dian)壓等(deng)(deng)級的(de)(de)電(dian)能，通(tong)(tong)訊系統(tong)進(jin)行(xing)(xing)模/數(shu)(shu)(shu)轉(zhuan)(zhuan)換及(ji)數(shu)(shu)(shu)據通(tong)(tong)信(xin)等(deng)(deng)。

2 CEMS系統運行方法(fa)

CEMS系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)的(de)(de)(de)(de)(de)(de)(de)運行(xing)可分為(wei)三個部分，系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)的(de)(de)(de)(de)(de)(de)(de)啟動、運行(xing)和停(ting)(ting)機(ji)。在(zai)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)啟動之前，應(ying)(ying)(ying)該(gai)對(dui)(dui)采(cai)(cai)樣探頭和伴(ban)熱(re)采(cai)(cai)樣線(xian)進(jin)行(xing)加(jia)熱(re)處理，當(dang)(dang)達(da)到(dao)溫(wen)(wen)度要求后(hou)(hou)，在(zai)開啟電(dian)源(yuan)啟動系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)。對(dui)(dui)伴(ban)熱(re)采(cai)(cai)樣線(xian)先行(xing)加(jia)熱(re)，是為(wei)了防(fang)止在(zai)低溫(wen)(wen)狀態下，濕氣(qi)引(yin)起的(de)(de)(de)(de)(de)(de)(de)腐蝕對(dui)(dui)機(ji)器造成損(sun)壞(huai)或(huo)者是因為(wei)樣氣(qi)含濕而影響到(dao)監(jian)測(ce)數據的(de)(de)(de)(de)(de)(de)(de)精度，如(ru)果煙(yan)氣(qi)的(de)(de)(de)(de)(de)(de)(de)含濕量太多的(de)(de)(de)(de)(de)(de)(de)話，其進(jin)入(ru)到(dao)監(jian)測(ce)儀器中(zhong)，將(jiang)會對(dui)(dui)儀器造成損(sun)壞(huai)。在(zai)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)正常(chang)運行(xing)后(hou)(hou)，應(ying)(ying)(ying)該(gai)根(gen)據實(shi)(shi)際情(qing)況對(dui)(dui)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)進(jin)行(xing)適(shi)當(dang)(dang)的(de)(de)(de)(de)(de)(de)(de)調(diao)整。在(zai)向鍋爐中(zhong)投料(liao)的(de)(de)(de)(de)(de)(de)(de)時候會產生大量的(de)(de)(de)(de)(de)(de)(de)煙(yan)塵(chen)，所以這時應(ying)(ying)(ying)該(gai)將(jiang)采(cai)(cai)樣裝(zhuang)置切換到(dao)反吹狀態防(fang)止煙(yan)塵(chen)的(de)(de)(de)(de)(de)(de)(de)進(jin)入(ru)。在(zai)不(bu)(bu)同(tong)的(de)(de)(de)(de)(de)(de)(de)季節，溫(wen)(wen)度也不(bu)(bu)同(tong)，所以應(ying)(ying)(ying)該(gai)根(gen)據溫(wen)(wen)度的(de)(de)(de)(de)(de)(de)(de)變化(hua)來(lai)對(dui)(dui)伴(ban)熱(re)線(xian)的(de)(de)(de)(de)(de)(de)(de)溫(wen)(wen)控系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)進(jin)行(xing)調(diao)整。在(zai)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)停(ting)(ting)機(ji)階(jie)段，不(bu)(bu)應(ying)(ying)(ying)該(gai)直(zhi)接將(jiang)電(dian)源(yuan)關(guan)閉(bi)，而是應(ying)(ying)(ying)該(gai)按照(zhao)正常(chang)的(de)(de)(de)(de)(de)(de)(de)關(guan)機(ji)程序(xu)來(lai)執行(xing)。首(shou)先要將(jiang)采(cai)(cai)樣系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)中(zhong)的(de)(de)(de)(de)(de)(de)(de)氣(qi)路排空，用(yong)壓縮空氣(qi)將(jiang)管線(xian)內的(de)(de)(de)(de)(de)(de)(de)殘余(yu)氣(qi)體清(qing)除干(gan)凈，然后(hou)(hou)將(jiang)氣(qi)路的(de)(de)(de)(de)(de)(de)(de)入(ru)口關(guan)閉(bi)，最后(hou)(hou)在(zai)關(guan)閉(bi)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)的(de)(de)(de)(de)(de)(de)(de)電(dian)源(yuan)。對(dui)(dui)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)中(zhong)的(de)(de)(de)(de)(de)(de)(de)反吹系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)，應(ying)(ying)(ying)該(gai)根(gen)據實(shi)(shi)際的(de)(de)(de)(de)(de)(de)(de)運行(xing)情(qing)況對(dui)(dui)鏡片(pian)進(jin)行(xing)清(qing)洗或(huo)者是停(ting)(ting)運。

3 CEMS系統(tong)維護

3.1 NOX測量原理

進(jin)(jin)行(xing)煙(yan)(yan)(yan)氣監測(ce)(ce)首先需要進(jin)(jin)行(xing)煙(yan)(yan)(yan)氣的(de)(de)(de)采(cai)集(ji)，利用取(qu)樣泵(beng)從煙(yan)(yan)(yan)道內(nei)取(qu)氣，然后通(tong)過(guo)(guo)(guo)伴熱(re)(re)(re)管(guan)(guan)線(xian)樣氣輸(shu)送到(dao)(dao)(dao)冷(leng)凝(ning)(ning)器(qi)(qi)中(zhong)(zhong)(zhong)。之所以(yi)(yi)會(hui)用到(dao)(dao)(dao)伴熱(re)(re)(re)管(guan)(guan)線(xian)，是因為(wei)煙(yan)(yan)(yan)氣的(de)(de)(de)溫度比較(jiao)高，而(er)輸(shu)送的(de)(de)(de)線(xian)路(lu)較(jiao)長，如(ru)果不(bu)進(jin)(jin)行(xing)加熱(re)(re)(re)處理的(de)(de)(de)話(hua)，那么煙(yan)(yan)(yan)氣在(zai)運輸(shu)的(de)(de)(de)過(guo)(guo)(guo)程(cheng)中(zhong)(zhong)(zhong)就會(hui)因為(wei)溫度降低而(er)使水(shui)分(fen)(fen)從煙(yan)(yan)(yan)氣中(zhong)(zhong)(zhong)分(fen)(fen)離出來，水(shui)分(fen)(fen)與煙(yan)(yan)(yan)氣中(zhong)(zhong)(zhong)的(de)(de)(de)NOX相互結合(he)產生化學(xue)反應，從而(er)形成硝酸，酸的(de)(de)(de)產生會(hui)對(dui)系統(tong)造成腐(fu)蝕造成系統(tong)的(de)(de)(de)損害，并且還(huan)會(hui)影響到(dao)(dao)(dao)測(ce)(ce)量的(de)(de)(de)準確性。在(zai)傳輸(shu)到(dao)(dao)(dao)冷(leng)凝(ning)(ning)器(qi)(qi)后，冷(leng)凝(ning)(ning)器(qi)(qi)中(zhong)(zhong)(zhong)的(de)(de)(de)蠕動(dong)泵(beng)會(hui)將煙(yan)(yan)(yan)氣中(zhong)(zhong)(zhong)水(shui)分(fen)(fen)排(pai)走，使其不(bu)與NOX接觸。在(zai)冷(leng)凝(ning)(ning)器(qi)(qi)上(shang)有管(guan)(guan)線(xian)與外界相通(tong)，可以(yi)(yi)使空氣進(jin)(jin)入到(dao)(dao)(dao)冷(leng)凝(ning)(ning)器(qi)(qi)中(zhong)(zhong)(zhong)，然后除去水(shui)分(fen)(fen)的(de)(de)(de)煙(yan)(yan)(yan)氣在(zai)經(jing)過(guo)(guo)(guo)氣體(ti)過(guo)(guo)(guo)濾(lv)器(qi)(qi)后傳送到(dao)(dao)(dao)氣體(ti)分(fen)(fen)析儀中(zhong)(zhong)(zhong)，從而(er)對(dui)煙(yan)(yan)(yan)氣進(jin)(jin)行(xing)檢測(ce)(ce)。在(zai)對(dui)煙(yan)(yan)(yan)氣進(jin)(jin)行(xing)取(qu)樣的(de)(de)(de)過(guo)(guo)(guo)程(cheng)中(zhong)(zhong)(zhong)，為(wei)了不(bu)使粉(fen)塵堵(du)塞到(dao)(dao)(dao)管(guan)(guan)路(lu)，在(zai)系統(tong)中(zhong)(zhong)(zhong)設定(ding)了定(ding)期清除功(gong)能，通(tong)過(guo)(guo)(guo)空氣壓(ya)縮(suo)機對(dui)伴熱(re)(re)(re)管(guan)(guan)線(xian)進(jin)(jin)行(xing)吹掃。

3.2 氣體分(fen)析儀啟用前的準備

3.2.1 啟動(dong)(dong)前的(de)準備。由于(yu)該儀器是(shi)氣(qi)體分析儀所以在啟動(dong)(dong)前首先要(yao)檢查(cha)氣(qi)體是(shi)否存在泄漏(lou)(lou)，檢查(cha)氣(qi)體是(shi)否泄漏(lou)(lou)通常(chang)用(yong)一個U型管壓(ya)(ya)力(li)(li)計(ji)便(bian)可以用(yong)最簡(jian)便(bian)的(de)方法測(ce)量(liang)出(chu)壓(ya)(ya)力(li)(li)。

3.2.2 分(fen)析儀(yi)(yi)的(de)標(biao)(biao)定(ding)。在(zai)分(fen)析儀(yi)(yi)安裝(zhuang)好之(zhi)后(hou)，可以用標(biao)(biao)定(ding)氣來對(dui)分(fen)析儀(yi)(yi)進(jin)行標(biao)(biao)定(ding)。標(biao)(biao)定(ding)應該(gai)使(shi)用一種含(han)有足夠濃度(du)被測組分(fen)氣體來進(jin)行。進(jin)行標(biao)(biao)定(ding)時應確保氣體流量在(zai)1.2-2.0L/min之(zhi)間。

3.3 氣(qi)路系(xi)統的維護

3.3.1 取樣(yang)(yang)探(tan)頭(tou)的(de)維護。針(zhen)對(dui)脫硝(xiao)煙(yan)道內高溫(wen)、高粉塵以及(ji)容(rong)易形成銨(an)鹽的(de)特(te)點，M6200型(xing)取樣(yang)(yang)探(tan)頭(tou)為(wei)高溫(wen)型(xing)探(tan)頭(tou)，材質為(wei)316L不銹鋼，樣(yang)(yang)氣首先經過裝(zhuang)有過濾(lv)精度(du)為(wei)2μ的(de)合金(jin)燒結前置(zhi)過濾(lv)器的(de)采樣(yang)(yang)探(tan)桿，通過外表面過濾(lv)的(de)方式，將大部分的(de)顆粒(li)物(wu)過濾(lv)掉(diao)，其中探(tan)桿插(cha)入煙(yan)道深(shen)度(du)為(wei)1.5 米。

煙(yan)氣(qi)(qi)進(jin)入溫(wen)(wen)度(du)(du)達(da)到320℃的(de)(de)探(tan)頭過(guo)(guo)濾(lv)裝置(zhi)，這個溫(wen)(wen)度(du)(du)與(yu)煙(yan)道溫(wen)(wen)度(du)(du)相仿，避(bi)免(mian)(mian)了取樣過(guo)(guo)濾(lv)過(guo)(guo)程中(zhong)煙(yan)氣(qi)(qi)溫(wen)(wen)度(du)(du)的(de)(de)巨大(da)變化帶來煙(yan)氣(qi)(qi)體積的(de)(de)巨大(da)變化形成冷凝，從而有效避(bi)免(mian)(mian)在探(tan)頭過(guo)(guo)濾(lv)器的(de)(de)地方(fang)(fang)出(chu)現硫酸氫銨鹽(yan)結晶體，形成堵塞(sai)；探(tan)頭內部配備了過(guo)(guo)濾(lv)精度(du)(du)為(wei)1.0-2.0μ的(de)(de)特殊合(he)金(jin)燒。結過(guo)(guo)濾(lv)器，通過(guo)(guo)外(wai)表面(mian)過(guo)(guo)濾(lv)的(de)(de)方(fang)(fang)式對(dui)煙(yan)氣(qi)(qi)中(zhong)的(de)(de)顆粒物(wu)進(jin)行有效過(guo)(guo)濾(lv)，將干(gan)凈的(de)(de)煙(yan)氣(qi)(qi)傳輸(shu)到儀表間。應每6個月檢查(cha)一次探(tan)頭過(guo)(guo)濾(lv)器，可以采用壓縮空氣(qi)(qi)對(dui)其進(jin)行吹掃清(qing)洗(xi)。如果濾(lv)芯嚴重(zhong)堵塞(sai)或者裂縫應及時更換。

3.3.2 采樣(yang)(yang)(yang)(yang)管(guan)(guan)線(xian)(xian)(xian)的(de)(de)維護(hu)。伴熱(re)管(guan)(guan)線(xian)(xian)(xian)加熱(re)功率(lv)為每(mei)米60W，讓取(qu)(qu)樣(yang)(yang)(yang)(yang)出(chu)(chu)來(lai)的(de)(de)煙氣(qi)在整個(ge)傳(chuan)輸過程中都保持180℃的(de)(de)高溫，保證(zheng)了樣(yang)(yang)(yang)(yang)氣(qi)在取(qu)(qu)樣(yang)(yang)(yang)(yang)管(guan)(guan)中不會產生(sheng)冷凝水(shui)，并出(chu)(chu)現(xian)硫酸氫銨(an)鹽的(de)(de)結晶體析出(chu)(chu)（根據有關研究文獻(xian)，硫酸氫銨(an)鹽的(de)(de)析出(chu)(chu)溫度為147℃）。采樣(yang)(yang)(yang)(yang)管(guan)(guan)線(xian)(xian)(xian)在平(ping)時是不需(xu)要(yao)進(jin)行(xing)維護(hu)的(de)(de)，但在平(ping)時要(yao)注(zhu)意管(guan)(guan)線(xian)(xian)(xian)上不能放置重物，如果有重物壓在管(guan)(guan)線(xian)(xian)(xian)上，管(guan)(guan)線(xian)(xian)(xian)在承力的(de)(de)作用下(xia)會使內部的(de)(de)取(qu)(qu)樣(yang)(yang)(yang)(yang)管(guan)(guan)與加熱(re)帶發生(sheng)接(jie)觸，從而導致(zhi)管(guan)(guan)線(xian)(xian)(xian)的(de)(de)損壞，一旦取(qu)(qu)樣(yang)(yang)(yang)(yang)管(guan)(guan)破損，則需(xu)要(yao)進(jin)行(xing)更換，沒有辦法進(jin)行(xing)修復(fu)。

3.3.3 冷凝器的維護。氣體冷凝器發(fa)生故(gu)障的機率較小，其維護工作也是半年更抽(chou)象一(yi)次蠕(ru)動泵(beng)(beng)泵(beng)(beng)管(guan)即可(ke)，這個泵(beng)(beng)管(guan)是安裝在(zai)冷凝器下端的，同(tong)時，如果(guo)發(fa)現冷凝器內(nei)有粉(fen)塵時，可(ke)以用人(ren)工用水進行清洗的辦法來進行處理。

3.3.4 保護(hu)過(guo)濾(lv)(lv)(lv)(lv)器(qi)(qi)(qi)的(de)(de)(de)維護(hu)。保護(hu)過(guo)濾(lv)(lv)(lv)(lv)器(qi)(qi)(qi)可(ke)以(yi)有效的(de)(de)(de)過(guo)濾(lv)(lv)(lv)(lv)煙氣(qi)中的(de)(de)(de)水(shui)汽和粉塵物(wu)，這(zhe)些(xie)東西附著(zhu)在保護(hu)過(guo)濾(lv)(lv)(lv)(lv)器(qi)(qi)(qi)上，濾(lv)(lv)(lv)(lv)紙則(ze)會慢慢的(de)(de)(de)變(bian)色，因此(ci)，發(fa)現濾(lv)(lv)(lv)(lv)紙變(bian)色后即及時進(jin)(jin)行更換，當前級氣(qi)路的(de)(de)(de)過(guo)濾(lv)(lv)(lv)(lv)器(qi)(qi)(qi)的(de)(de)(de)探頭失(shi)去效用時，保護(hu)過(guo)濾(lv)(lv)(lv)(lv)器(qi)(qi)(qi)的(de)(de)(de)濾(lv)(lv)(lv)(lv)芯變(bian)色則(ze)會較快，這(zhe)時就(jiu)應(ying)該(gai)對前級過(guo)濾(lv)(lv)(lv)(lv)器(qi)(qi)(qi)進(jin)(jin)行檢(jian)查，應(ying)該(gai)是冷凝器(qi)(qi)(qi)工作失(shi)常所(suo)致。

3.3.5 測(ce)(ce)塵(chen)儀的(de)維護(hu)。對(dui)于測(ce)(ce)塵(chen)儀的(de)維護(hu)，一般時(shi)候是(shi)每(mei)三(san)個月檢(jian)查一次，但對(dui)于檢(jian)查時(shi)發現測(ce)(ce)塵(chen)儀所(suo)運行(xing)的(de)環境較為惡劣時(shi)，則(ze)應該經常更換空氣過濾器。正(zheng)常情況下(xia)，測(ce)(ce)塵(chen)儀只要光(guang)學窗(chuang)口保持清(qing)(qing)潔即可(ke)，因其對(dui)于測(ce)(ce)量結果(guo)的(de)準確(que)性有(you)著直接(jie)的(de)影(ying)響。所(suo)以在(zai)平時(shi)維護(hu)時(shi)，需要用(yong)百(bai)分之(zhi)五十的(de)酒精(jing)(jing)和蒸(zheng)餾(liu)水的(de)溶液做為清(qing)(qing)潔液來(lai)對(dui)測(ce)(ce)塵(chen)儀的(de)光(guang)學窗(chuang)口進行(xing)清(qing)(qing)潔，但這里(li)對(dui)酒精(jing)(jing)有(you)要求，需要化學純級(ji)的(de)酒精(jing)(jing)，保證酒精(jing)(jing)里(li)不(bu)能(neng)含有(you)油質，因為含有(you)油質的(de)酒精(jing)(jing)在(zai)酒精(jing)(jing)揮發后(hou)則(ze)會有(you)油質留下(xia)，影(ying)響光(guang)學窗(chuang)口的(de)清(qing)(qing)潔度，因此就會導(dao)致測(ce)(ce)量結果(guo)的(de)不(bu)準確(que)。

4 結束語

CEMS 煙氣連續(xu)監測系統已(yi)得到廣泛應用，在線(xian)監測了(le)電力(li)生產過程中產生 污染氣體的固定排放(fang)(fang)源(yuan)以及(ji)(ji)煙氣脫(tuo)硫(liu)、脫(tuo)硝系統的控制和監測，有(you)(you)利(li)于運行(xing)人員及(ji)(ji)時調(diao)整與監控脫(tuo)硫(liu)、脫(tuo)硝、除塵等環保設施的運行(xing)狀態，加強(qiang)達標排放(fang)(fang)管(guan)理，為(wei)環保部門(men)的監督提供 了(le)科學先進的檢測手段，這對于排放(fang)(fang)點(dian)的有(you)(you)效監測與管(guan)理有(you)(you)著(zhu)積(ji)極而重(zhong)要的意義(yi)。