摘要

新《火電廠(chang)大氣污染物排放標準》執行(xing)對電力行(xing)業氮氧化物排放提出了嚴(yan)格的限制(zhi)(zhi)(zhi)，SCR煙(yan)氣脫(tuo)硝(xiao)(xiao)技術成為火電廠(chang)控(kong)制(zhi)(zhi)(zhi)氮氧化合物的必然(ran)選擇，還原劑氨是影(ying)響SCR煙(yan)氣脫(tuo)硝(xiao)(xiao)系統脫(tuo)硝(xiao)(xiao)效率的關鍵因素，國內(nei)許多SCR脫(tuo)硝(xiao)(xiao)裝(zhuang)置為電廠(chang)后期改造項目，對SCR系統噴(pen)氨混(hun)(hun)合裝(zhuang)置進行(xing)優化研究(jiu)具有重(zhong)要意義，本文提出了新型噴(pen)氨混(hun)(hun)合單元設(she)計思想。設(she)計控(kong)制(zhi)(zhi)(zhi)氨逃逸的優化調整(zheng)方(fang)法，根據(ju)脫(tuo)硝(xiao)(xiao)系統出口NO分布情況調整(zheng)噴(pen)氨系統，其優化調整(zheng)后效果有差異，分區控(kong)制(zhi)(zhi)(zhi)噴(pen)氨格柵技術效果最顯著。

火(huo)電(dian)廠生產(chan)排放的(de)NOx總量(liang)不斷(duan)上升(sheng)，NOx在煙氣中主要以不穩定的(de)NO形式存在，NOx危害很(hen)多，會引發(fa)空氣細粒子污(wu)染，與(yu)大氣中的(de)氧(yang)氣發(fa)生反(fan)應生成對(dui)人體有(you)害的(de)臭氧(yang)。國內已安(an)裝脫(tuo)(tuo)硝系統(tong)(tong)燃煤(mei)機組有(you)548臺，采用(yong)選(xuan)擇性催化還原(yuan)脫(tuo)(tuo)硝系統(tong)(tong)的(de)機組有(you)433臺，SCR煙氣脫(tuo)(tuo)硝技術以其(qi)實用(yong)性等方面展示(shi)出(chu)強大優勢，在我國火(huo)電(dian)廠脫(tuo)(tuo)硝工(gong)程(cheng)中得到了廣泛的(de)應用(yong)。SCR脫(tuo)(tuo)硝系統(tong)(tong)運(yun)行狀況(kuang)重(zhong)要依據是(shi)脫(tuo)(tuo)硝效率，SCR脫(tuo)(tuo)硝系統(tong)(tong)出(chu)口的(de)NOx濃度是(shi)指標(biao)決定性的(de)影響因素(su)。

1SCR技(ji)術

1.1SCR系(xi)統(tong)布置方式

高(gao)(gao)(gao)灰(hui)塵(chen)布(bu)(bu)置(zhi)(zhi)的(de)(de)反(fan)應(ying)(ying)器(qi)(qi)位于(yu)鍋爐省煤器(qi)(qi)與空氣(qi)預熱(re)器(qi)(qi)之(zhi)間，投資(zi)運(yun)行費(fei)用低。催(cui)(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)耐高(gao)(gao)(gao)溫能力有限，煙氣(qi)溫度過高(gao)(gao)(gao)會縮短催(cui)(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)使(shi)用壽命，未經處(chu)理的(de)(de)煙氣(qi)中含有大量(liang)灰(hui)塵(chen)，催(cui)(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)長期運(yun)行于(yu)高(gao)(gao)(gao)塵(chen)環(huan)境(jing)會出現中毒現象，灰(hui)塵(chen)顆粒造(zao)成(cheng)(cheng)催(cui)(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)的(de)(de)堵塞等問(wen)題。為減少(shao)催(cui)(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)的(de)(de)磨損(sun)，SCR系統(tong)催(cui)(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)采用豎直布(bu)(bu)置(zhi)(zhi)，使(shi)用蜂窩狀催(cui)(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)開(kai)孔較大，其幾何表(biao)面積(ji)比低飛(fei)灰(hui)段布(bu)(bu)置(zhi)(zhi)所用催(cui)(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)小。高(gao)(gao)(gao)灰(hui)布(bu)(bu)置(zhi)(zhi)是(shi)經濟有效的(de)(de)布(bu)(bu)置(zhi)(zhi)方(fang)式。低灰(hui)布(bu)(bu)置(zhi)(zhi)反(fan)應(ying)(ying)器(qi)(qi)位于(yu)高(gao)(gao)(gao)溫靜電除(chu)塵(chen)器(qi)(qi)后(hou)，次(ci)方(fang)法的(de)(de)優(you)點是(shi)煙氣(qi)中飛(fei)灰(hui)含量(liang)大幅(fu)減少(shao)，不易發生催(cui)(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)磨損(sun)。缺點是(shi)需要使(shi)用耐高(gao)(gao)(gao)溫除(chu)塵(chen)器(qi)(qi)，我國(guo)電廠(chang)沒有高(gao)(gao)(gao)溫除(chu)塵(chen)布(bu)(bu)置(zhi)(zhi)形式。低溫低灰(hui)布(bu)(bu)置(zhi)(zhi)反(fan)應(ying)(ying)器(qi)(qi)位于(yu)除(chu)塵(chen)器(qi)(qi)與脫硫系統(tong)后(hou)，不會造(zao)成(cheng)(cheng)催(cui)(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)堵塞。脫硫系統(tong)可大幅(fu)降低煙氣(qi)中的(de)(de)SO2濃度，可以使(shi)用高(gao)(gao)(gao)活性催(cui)(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)減少(shao)催(cui)(cui)(cui)(cui)化(hua)(hua)(hua)(hua)劑(ji)(ji)的(de)(de)消耗量(liang)。

1.2SCR脫硝系統流程

SCR脫(tuo)(tuo)(tuo)(tuo)(tuo)硝(xiao)(xiao)系(xi)(xi)統(tong)(tong)(tong)(tong)是(shi)火(huo)電(dian)廠發(fa)(fa)電(dian)新增的(de)煙(yan)氣(qi)處理環節，老電(dian)廠最(zui)初(chu)不具備脫(tuo)(tuo)(tuo)(tuo)(tuo)硝(xiao)(xiao)系(xi)(xi)統(tong)(tong)(tong)(tong)，改造脫(tuo)(tuo)(tuo)(tuo)(tuo)硝(xiao)(xiao)系(xi)(xi)統(tong)(tong)(tong)(tong)首先(xian)要解(jie)決脫(tuo)(tuo)(tuo)(tuo)(tuo)硝(xiao)(xiao)系(xi)(xi)統(tong)(tong)(tong)(tong)布(bu)置(zhi)(zhi)問(wen)題，燃氣(qi)輪機(ji)的(de)SCR脫(tuo)(tuo)(tuo)(tuo)(tuo)硝(xiao)(xiao)系(xi)(xi)統(tong)(tong)(tong)(tong)布(bu)置(zhi)(zhi)不同，某電(dian)廠SCR脫(tuo)(tuo)(tuo)(tuo)(tuo)硝(xiao)(xiao)系(xi)(xi)統(tong)(tong)(tong)(tong)按(an)照高溫(wen)飛灰方(fang)式(shi)(shi)布(bu)置(zhi)(zhi)。高溫(wen)飛灰布(bu)置(zhi)(zhi)是(shi)目前火(huo)電(dian)廠最(zui)常見(jian)的(de)SCR脫(tuo)(tuo)(tuo)(tuo)(tuo)硝(xiao)(xiao)系(xi)(xi)統(tong)(tong)(tong)(tong)布(bu)置(zhi)(zhi)工(gong)藝(yi)，SCR脫(tuo)(tuo)(tuo)(tuo)(tuo)硝(xiao)(xiao)反(fan)(fan)應器處于(yu)(yu)(yu)省(sheng)煤(mei)器與(yu)空氣(qi)預熱器中間(jian)位置(zhi)(zhi)，在噴氨(an)(an)(an)柵格(ge)部位與(yu)經稀釋(shi)后的(de)氨(an)(an)(an)氣(qi)相(xiang)遇，煙(yan)氣(qi)經空氣(qi)預熱器與(yu)引風機(ji)進(jin)入到(dao)脫(tuo)(tuo)(tuo)(tuo)(tuo)硫系(xi)(xi)統(tong)(tong)(tong)(tong)。液氨(an)(an)(an)是(shi)物(wu)色的(de)液體，易溶于(yu)(yu)(yu)水，具有一定的(de)腐蝕性，液氨(an)(an)(an)儲存系(xi)(xi)統(tong)(tong)(tong)(tong)必須具備極高的(de)可靠性。其(qi)構成(cheng)包括(kuo)兩(liang)個液氨(an)(an)(an)臥式(shi)(shi)儲存罐，氨(an)(an)(an)氣(qi)吹掃系(xi)(xi)統(tong)(tong)(tong)(tong)等。工(gong)業生產中氨(an)(an)(an)氣(qi)制備方(fang)法(fa)主要有液氨(an)(an)(an)法(fa)、尿(niao)素(su)法(fa)。尿(niao)素(su)法(fa)安全性高于(yu)(yu)(yu)液氨(an)(an)(an)法(fa)，液氨(an)(an)(an)法(fa)經濟性優于(yu)(yu)(yu)氨(an)(an)(an)水法(fa)。電(dian)廠采用(yong)也(ye)案發(fa)(fa)氨(an)(an)(an)氣(qi)制備系(xi)(xi)統(tong)(tong)(tong)(tong)，構成(cheng)主要包括(kuo)三臺蒸氣(qi)加熱水浴式(shi)(shi)液氨(an)(an)(an)蒸發(fa)(fa)罐及相(xiang)應管道(dao)。SCR脫(tuo)(tuo)(tuo)(tuo)(tuo)硝(xiao)(xiao)反(fan)(fan)應系(xi)(xi)統(tong)(tong)(tong)(tong)是(shi)脫(tuo)(tuo)(tuo)(tuo)(tuo)硝(xiao)(xiao)系(xi)(xi)統(tong)(tong)(tong)(tong)中的(de)關(guan)鍵(jian)系(xi)(xi)統(tong)(tong)(tong)(tong)，主要包括(kuo)稀釋(shi)風機(ji)、兩(liang)套噴氨(an)(an)(an)格(ge)柵、一套吹灰系(xi)(xi)統(tong)(tong)(tong)(tong)。SCR脫(tuo)(tuo)(tuo)(tuo)(tuo)硝(xiao)(xiao)工(gong)藝(yi)中發(fa)(fa)生的(de)反(fan)(fan)應是(shi)催(cui)化(hua)還原反(fan)(fan)應，煙(yan)氣(qi)中的(de)NOx與(yu)NH3催(cui)化(hua)劑(ji)作(zuo)用(yong)下反(fan)(fan)應生成(cheng)無害的(de)N2與(yu)H2O。降(jiang)低煙(yan)氣(qi)中NOx濃度。

1.3SCR系(xi)統運行特性參數

影響SCR系(xi)(xi)統(tong)運行特(te)性的(de)(de)參(can)數主要有溫(wen)度(du)、還原劑(ji)與(yu)煙氣(qi)混(hun)(hun)合情況(kuang)、NOx濃度(du)等。NOx還原反(fan)(fan)(fan)(fan)(fan)(fan)應(ying)(ying)只(zhi)有在其催(cui)(cui)化(hua)劑(ji)有最佳(jia)(jia)活(huo)性溫(wen)度(du)范圍才(cai)能維持很高的(de)(de)脫硝率，過(guo)高溫(wen)度(du)會降低(di)催(cui)(cui)化(hua)劑(ji)壽(shou)命。大多(duo)數燃煤電(dian)站使用(yong)商(shang)業催(cui)(cui)化(hua)劑(ji)，SCR反(fan)(fan)(fan)(fan)(fan)(fan)應(ying)(ying)最佳(jia)(jia)溫(wen)度(du)范圍為250～450℃。停(ting)(ting)留(liu)(liu)時間是反(fan)(fan)(fan)(fan)(fan)(fan)應(ying)(ying)物在反(fan)(fan)(fan)(fan)(fan)(fan)應(ying)(ying)器中的(de)(de)時間，溫(wen)度(du)會影響停(ting)(ting)留(liu)(liu)時間，停(ting)(ting)留(liu)(liu)時間通(tong)(tong)常按其導數值空(kong)速表達(da)，可用(yong)反(fan)(fan)(fan)(fan)(fan)(fan)應(ying)(ying)器體積與(yu)煙氣(qi)流速比值估算空(kong)速。還原劑(ji)必須與(yu)煙氣(qi)充分(fen)均勻(yun)混(hun)(hun)合才(cai)能確保與(yu)反(fan)(fan)(fan)(fan)(fan)(fan)應(ying)(ying)物充分(fen)結(jie)合，氨(an)噴(pen)射系(xi)(xi)統(tong)將氨(an)氣(qi)與(yu)空(kong)氣(qi)混(hun)(hun)合物均勻(yun)混(hun)(hun)入煙氣(qi)，許多(duo)SCR系(xi)(xi)統(tong)將NH3一起噴(pen)入煙氣(qi)防止事故出現。通(tong)(tong)過(guo)對(dui)反(fan)(fan)(fan)(fan)(fan)(fan)應(ying)(ying)器內(nei)部流場(chang)數值模擬可達(da)到優化(hua)氨(an)噴(pen)射工況(kuang)的(de)(de)目的(de)(de)。未(wei)完(wan)全反(fan)(fan)(fan)(fan)(fan)(fan)應(ying)(ying)NH3通(tong)(tong)過(guo)反(fan)(fan)(fan)(fan)(fan)(fan)應(ying)(ying)器進(jin)入下(xia)(xia)(xia)游設備使其發生銨鹽腐蝕(shi)，可采用(yong)調節氨(an)的(de)(de)噴(pen)入量為SCR系(xi)(xi)統(tong)設計輔(fu)助設備方(fang)法降低(di)NH3逃(tao)逸(yi)。NH3逃(tao)逸(yi)率并非(fei)穩定(ding)不變，催(cui)(cui)化(hua)劑(ji)活(huo)性下(xia)(xia)(xia)降時，還原反(fan)(fan)(fan)(fan)(fan)(fan)應(ying)(ying)特(te)性下(xia)(xia)(xia)降，量化(hua)氨(an)逃(tao)逸(yi)的(de)(de)方(fang)法是測量飛灰(hui)上的(de)(de)氨(an)濃度(du)。

1.4SCR反應器設計(ji)

優(you)化(hua)SCR系統(tong)設(she)(she)計(ji)中(zhong)，反(fan)(fan)應(ying)(ying)器(qi)(qi)設(she)(she)計(ji)直(zhi)接影響SCR系統(tong)運(yun)行(xing)特(te)性(xing)，反(fan)(fan)應(ying)(ying)器(qi)(qi)設(she)(she)計(ji)不(bu)佳(jia)時，SCR工藝系統(tong)運(yun)行(xing)特(te)性(xing)也(ye)不(bu)理(li)想(xiang)。反(fan)(fan)應(ying)(ying)器(qi)(qi)設(she)(she)計(ji)中(zhong)主要解決速(su)度(du)(du)分(fen)布(bu)、飛灰顆粒(li)分(fen)布(bu)問(wen)題(ti)。在(zai)SCR技術商(shang)業化(hua)后模(mo)擬(ni)實驗技術被系統(tong)工藝商(shang)用(yong)來(lai)模(mo)擬(ni)SCR反(fan)(fan)應(ying)(ying)器(qi)(qi)內(nei)部流場(chang)特(te)性(xing)，一般將實驗臺按實際反(fan)(fan)應(ying)(ying)器(qi)(qi)的(de)1/20-1/10縮小，通過對(dui)(dui)流場(chang)優(you)化(hua)可(ke)(ke)以在(zai)AIG入(ru)口(kou)速(su)度(du)(du)分(fen)布(bu)，最小系統(tong)降壓，最下化(hua)飛灰顆粒(li)在(zai)反(fan)(fan)應(ying)(ying)器(qi)(qi)內(nei)沉積。所有涉及流體(ti)流通、分(fen)子運(yun)輸等現象問(wen)題(ti)，可(ke)(ke)借助(zhu)CFD得(de)(de)到(dao)解決。采用(yong)計(ji)算機數(shu)值(zhi)(zhi)模(mo)擬(ni)計(ji)算是國內(nei)研究者普遍(bian)采用(yong)的(de)手段(duan)，國外很多SCR系統(tong)工藝商(shang)運(yun)用(yong)CFD技術對(dui)(dui)反(fan)(fan)應(ying)(ying)器(qi)(qi)進(jin)行(xing)數(shu)值(zhi)(zhi)模(mo)擬(ni)。對(dui)(dui)SCR反(fan)(fan)應(ying)(ying)器(qi)(qi)進(jin)行(xing)數(shu)值(zhi)(zhi)模(mo)擬(ni)可(ke)(ke)以得(de)(de)到(dao)與冷態(tai)實驗相同標(biao)準的(de)流動特(te)性(xing)、經濟的(de)預(yu)測煙氣溫(wen)度(du)(du)分(fen)布(bu)及飛灰顆粒(li)濃度(du)(du)分(fen)布(bu)等。數(shu)值(zhi)(zhi)模(mo)擬(ni)的(de)靈活性(xing)較好，其(qi)(qi)結果的(de)保存引用(yong)較容易，數(shu)值(zhi)(zhi)模(mo)擬(ni)的(de)入(ru)口(kou)邊界條件可(ke)(ke)靈活地改變，隨著SCR裝(zhuang)置(zhi)需求量增大(da)，其(qi)(qi)安(an)裝(zhuang)時間日益減少(shao)，大(da)多數(shu)系統(tong)工藝商(shang)結合(he)使用(yong)兩種手段(duan)設(she)(she)計(ji)改進(jin)SCR反(fan)(fan)應(ying)(ying)器(qi)(qi)。

2煙氣脫硝系(xi)統氨逃逸問(wen)題

隨著我國(guo)電力工業的發(fa)(fa)展，NOx產(chan)生(sheng)的污染問題引起了(le)人們的關注，新建發(fa)(fa)電機組(zu)要求安(an)裝選擇性催(cui)(cui)化(hua)(hua)還原(yuan)(yuan)煙(yan)氣(qi)(qi)脫(tuo)硝(xiao)(xiao)裝置(zhi)，未安(an)裝SCR煙(yan)氣(qi)(qi)脫(tuo)硝(xiao)(xiao)裝置(zhi)的投產(chan)機組(zu)逐步改造安(an)裝SCR煙(yan)氣(qi)(qi)脫(tuo)硝(xiao)(xiao)裝置(zhi)。SCR煙(yan)氣(qi)(qi)脫(tuo)硝(xiao)(xiao)原(yuan)(yuan)理是(shi)煙(yan)氣(qi)(qi)噴入氨(an)將(jiang)NOx催(cui)(cui)化(hua)(hua)還原(yuan)(yuan)成(cheng)Nx與(yu)(yu)H2O，噴入的氨(an)氣(qi)(qi)與(yu)(yu)煙(yan)氣(qi)(qi)不(bu)能完全均勻(yun)混合，煙(yan)氣(qi)(qi)中的水蒸氣(qi)(qi)與(yu)(yu)逃逸氨(an)在一(yi)(yi)定(ding)條件下反應生(sheng)成(cheng)硫(liu)(liu)酸(suan)氫(qing)銨，在液態下是(shi)腐蝕性物質，硫(liu)(liu)酸(suan)氫(qing)銨初(chu)(chu)始生(sheng)成(cheng)溫度(du)是(shi)SO3與(yu)(yu)氨(an)濃度(du)的函數，對(dui)典型的低碳煤(mei)硫(liu)(liu)酸(suan)氫(qing)氨(an)初(chu)(chu)始生(sheng)成(cheng)溫度(du)為200～220℃。大型燃(ran)煤(mei)發(fa)(fa)電機組(zu)多采用容(rong)克式空(kong)氣(qi)(qi)預熱(re)(re)器(qi)進行(xing)(xing)加熱(re)(re)，低溫段(duan)傳熱(re)(re)元件表面粘結，導(dao)(dao)致(zhi)空(kong)預器(qi)出現壓(ya)降上(shang)升等現象。空(kong)預器(qi)壓(ya)損(sun)(sun)率是(shi)運行(xing)(xing)一(yi)(yi)段(duan)時間后的壓(ya)損(sun)(sun)與(yu)(yu)開(kai)始投運壓(ya)損(sun)(sun)比。由(you)于硫(liu)(liu)酸(suan)氫(qing)銨導(dao)(dao)致(zhi)空(kong)預器(qi)堵塞，空(kong)預器(qi)壓(ya)損(sun)(sun)上(shang)升慢，同噴氨(an)優(you)化(hua)(hua)實驗可調整脫(tuo)硝(xiao)(xiao)系統氨(an)分布(bu)，對(dui)其(qi)機組(zu)的節能運行(xing)(xing)具有(you)重要意義。

3優化(hua)調整試驗

3.1試驗(yan)方法

目前應用于(yu)燃(ran)煤電(dian)站鍋爐SCR煙(yan)(yan)氣(qi)脫硝(xiao)(xiao)系統的(de)氨(an)噴(pen)(pen)(pen)(pen)(pen)(pen)射(she)(she)技術(shu)(shu)主(zhu)要有分(fen)(fen)區(qu)控(kong)制(zhi)(zhi)式(shi)(shi)噴(pen)(pen)(pen)(pen)(pen)(pen)射(she)(she)格柵(zha)噴(pen)(pen)(pen)(pen)(pen)(pen)氨(an)技術(shu)(shu)，線性控(kong)制(zhi)(zhi)式(shi)(shi)噴(pen)(pen)(pen)(pen)(pen)(pen)射(she)(she)格柵(zha)噴(pen)(pen)(pen)(pen)(pen)(pen)氨(an)技術(shu)(shu)。渦流(liu)式(shi)(shi)靜態混(hun)(hun)合(he)噴(pen)(pen)(pen)(pen)(pen)(pen)射(she)(she)技術(shu)(shu)特點是噴(pen)(pen)(pen)(pen)(pen)(pen)氨(an)嘴個稅(shui)與(yu)靜態混(hun)(hun)合(he)器(qi)片數一樣，利用煙(yan)(yan)氣(qi)流(liu)過的(de)混(hun)(hun)合(he)器(qi)片產生渦流(liu)使煙(yan)(yan)氣(qi)與(yu)所噴(pen)(pen)(pen)(pen)(pen)(pen)入(ru)氨(an)氣(qi)混(hun)(hun)合(he)。線性控(kong)制(zhi)(zhi)式(shi)(shi)噴(pen)(pen)(pen)(pen)(pen)(pen)射(she)(she)格柵(zha)噴(pen)(pen)(pen)(pen)(pen)(pen)氨(an)技術(shu)(shu)特點是引(yin)入(ru)若干根(gen)管，每根(gen)管流(liu)量(liang)可(ke)單獨調(diao)(diao)節，分(fen)(fen)布(bu)控(kong)制(zhi)(zhi)式(shi)(shi)噴(pen)(pen)(pen)(pen)(pen)(pen)射(she)(she)格柵(zha)噴(pen)(pen)(pen)(pen)(pen)(pen)氨(an)技術(shu)(shu)是將煙(yan)(yan)氣(qi)截面分(fen)(fen)成20～50個相同(tong)區(qu)域。降(jiang)低SCR脫硝(xiao)(xiao)系統氨(an)逃逸量(liang)，需使噴(pen)(pen)(pen)(pen)(pen)(pen)入(ru)脫硝(xiao)(xiao)系統氨(an)氣(qi)與(yu)煙(yan)(yan)氣(qi)NO呈對應分(fen)(fen)布(bu)，獲得可(ke)用于(yu)不同(tong)噴(pen)(pen)(pen)(pen)(pen)(pen)氨(an)技術(shu)(shu)的(de)噴(pen)(pen)(pen)(pen)(pen)(pen)氨(an)優化(hua)調(diao)(diao)整方法。

3.2優化調整試驗結(jie)果分(fen)析

寧海(hai)發電廠(chang)4號爐脫(tuo)硝(xiao)(xiao)系(xi)(xi)(xi)統(tong)噴(pen)氨(an)(an)(an)采用(yong)線性控制式(shi)噴(pen)射格柵，優(you)(you)(you)化(hua)(hua)調(diao)整(zheng)(zheng)前(qian)(qian)(qian)(qian)，脫(tuo)硝(xiao)(xiao)系(xi)(xi)(xi)統(tong)AB側(ce)出(chu)口NO分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)布(bu)不(bu)均(jun)度(du)(du)(du)為(wei)38%、31%，AB兩側(ce)靠近鍋(guo)爐中心區(qu)(qu)域NO含量(liang)較(jiao)低，經優(you)(you)(you)化(hua)(hua)調(diao)整(zheng)(zheng)后脫(tuo)硝(xiao)(xiao)系(xi)(xi)(xi)統(tong)AB側(ce)出(chu)口NO分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)布(bu)不(bu)均(jun)度(du)(du)(du)小于30%，測(ce)試系(xi)(xi)(xi)統(tong)優(you)(you)(you)化(hua)(hua)前(qian)(qian)(qian)(qian)后氨(an)(an)(an)逃逸(yi)情(qing)況，脫(tuo)硝(xiao)(xiao)系(xi)(xi)(xi)統(tong)氨(an)(an)(an)逃逸(yi)體積(ji)(ji)分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)數(shu)為(wei)1.8μL/L，氨(an)(an)(an)逃逸(yi)量(liang)響應降(jiang)低33%。浙江北侖發電廠(chang)6號機(ji)組脫(tuo)硝(xiao)(xiao)系(xi)(xi)(xi)統(tong)采用(yong)渦(wo)流(liu)混(hun)(hun)合技(ji)術，AB反(fan)應器(qi)設置5渦(wo)流(liu)混(hun)(hun)合器(qi)，需要(yao)較(jiao)長的混(hun)(hun)合距離(li)實(shi)現均(jun)勻混(hun)(hun)合。較(jiao)難通過優(you)(you)(you)化(hua)(hua)調(diao)整(zheng)(zheng)試驗實(shi)現煙(yan)氣與(yu)(yu)噴(pen)氨(an)(an)(an)的均(jun)勻混(hun)(hun)合。優(you)(you)(you)化(hua)(hua)調(diao)整(zheng)(zheng)前(qian)(qian)(qian)(qian)AB側(ce)分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)布(bu)不(bu)均(jun)度(du)(du)(du)為(wei)67%、51%，反(fan)應器(qi)A中部偏(pian)左(zuo)區(qu)(qu)域與(yu)(yu)B中部偏(pian)右區(qu)(qu)域存(cun)在(zai)NO測(ce)試值很(hen)低的情(qing)況，表明(ming)(ming)區(qu)(qu)域噴(pen)氨(an)(an)(an)量(liang)相對(dui)過量(liang)。優(you)(you)(you)化(hua)(hua)調(diao)整(zheng)(zheng)前(qian)(qian)(qian)(qian)AB脫(tuo)硝(xiao)(xiao)反(fan)應器(qi)出(chu)口NO分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)布(bu)測(ce)試結果，調(diao)整(zheng)(zheng)反(fan)應器(qi)渦(wo)流(liu)混(hun)(hun)合器(qi)氨(an)(an)(an)氣調(diao)節閥(fa)開度(du)(du)(du)，使氨(an)(an)(an)氣分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)布(bu)更(geng)好地參(can)與(yu)(yu)NO分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)布(bu)匹配(pei)，AB脫(tuo)硝(xiao)(xiao)反(fan)應器(qi)出(chu)口分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)布(bu)不(bu)均(jun)度(du)(du)(du)為(wei)27%、26%，由于只能(neng)在(zai)煙(yan)道一個方(fang)向進行(xing)噴(pen)氨(an)(an)(an)量(liang)調(diao)整(zheng)(zheng)，難以降(jiang)低脫(tuo)硝(xiao)(xiao)系(xi)(xi)(xi)統(tong)出(chu)口NO分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)布(bu)不(bu)均(jun)度(du)(du)(du)，測(ce)試脫(tuo)硝(xiao)(xiao)系(xi)(xi)(xi)統(tong)優(you)(you)(you)化(hua)(hua)前(qian)(qian)(qian)(qian)后氨(an)(an)(an)逃逸(yi)情(qing)況，優(you)(you)(you)化(hua)(hua)后脫(tuo)硝(xiao)(xiao)氨(an)(an)(an)逃逸(yi)體積(ji)(ji)分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)數(shu)為(wei)14μL/L，氨(an)(an)(an)逃逸(yi)量(liang)降(jiang)低17%。寧海(hai)電廠(chang)6號機(ji)組脫(tuo)硝(xiao)(xiao)系(xi)(xi)(xi)統(tong)采用(yong)分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)區(qu)(qu)控制方(fang)式(shi)布(bu)置噴(pen)氨(an)(an)(an)閥(fa)門(men)(men)，AB側(ce)噴(pen)氨(an)(an)(an)截面有48個噴(pen)氨(an)(an)(an)分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)區(qu)(qu)，噴(pen)氨(an)(an)(an)閥(fa)門(men)(men)控制噴(pen)氨(an)(an)(an)分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)區(qu)(qu)，在(zai)煙(yan)氣橫縱向進行(xing)噴(pen)氨(an)(an)(an)量(liang)調(diao)整(zheng)(zheng)。優(you)(you)(you)化(hua)(hua)調(diao)整(zheng)(zheng)前(qian)(qian)(qian)(qian)脫(tuo)硝(xiao)(xiao)反(fan)應器(qi)出(chu)口NO分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)布(bu)不(bu)均(jun)度(du)(du)(du)為(wei)22%，反(fan)應器(qi)A側(ce)爐前(qian)(qian)(qian)(qian)NO濃(nong)(nong)度(du)(du)(du)明(ming)(ming)顯平均(jun)偏(pian)高(gao)。A側(ce)爐后NO濃(nong)(nong)度(du)(du)(du)明(ming)(ming)顯較(jiao)平均(jun)值偏(pian)低。需要(yao)對(dui)區(qu)(qu)域噴(pen)氨(an)(an)(an)量(liang)進行(xing)調(diao)整(zheng)(zheng)。優(you)(you)(you)化(hua)(hua)調(diao)整(zheng)(zheng)后NO分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)布(bu)不(bu)均(jun)度(du)(du)(du)較(jiao)優(you)(you)(you)化(hua)(hua)前(qian)(qian)(qian)(qian)有所降(jiang)低。使反(fan)應器(qi)前(qian)(qian)(qian)(qian)氨(an)(an)(an)氣濃(nong)(nong)度(du)(du)(du)分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)布(bu)與(yu)(yu)NO濃(nong)(nong)度(du)(du)(du)更(geng)匹配(pei)，優(you)(you)(you)化(hua)(hua)前(qian)(qian)(qian)(qian)脫(tuo)硝(xiao)(xiao)系(xi)(xi)(xi)統(tong)氨(an)(an)(an)逃逸(yi)體積(ji)(ji)分(fen)(fen)(fen)(fen)(fen)(fen)(fen)(fen)數(shu)為(wei)1.9μL/L，優(you)(you)(you)化(hua)(hua)后氨(an)(an)(an)逃逸(yi)量(liang)響應降(jiang)低59%。

4結語

將SCR脫(tuo)(tuo)硝系(xi)(xi)統(tong)出口(kou)NO分(fen)(fen)(fen)布不(bu)(bu)均(jun)度30%作(zuo)為優化調(diao)整指標，調(diao)整氨的(de)(de)分(fen)(fen)(fen)布，可實現脫(tuo)(tuo)硝系(xi)(xi)統(tong)優化。采用(yong)不(bu)(bu)同噴(pen)氨技(ji)術(shu)(shu)的(de)(de)脫(tuo)(tuo)硝系(xi)(xi)統(tong)，優化調(diao)整結(jie)果有差別，分(fen)(fen)(fen)區控制噴(pen)氨格柵技(ji)術(shu)(shu)效(xiao)果最顯著，效(xiao)果一般的(de)(de)為渦流混合(he)技(ji)術(shu)(shu)。SCR脫(tuo)(tuo)硝系(xi)(xi)統(tong)出口(kou)NO的(de)(de)均(jun)勻(yun)性對(dui)SCR脫(tuo)(tuo)硝系(xi)(xi)統(tong)運行起(qi)到重(zhong)要作(zuo)用(yong)。經過噴(pen)氨優化調(diao)整試驗(yan)，氨氣(qi)量(liang)能與煙道內(nei)煙氣(qi)中NO濃(nong)度充分(fen)(fen)(fen)反(fan)應，減(jian)少硫酸(suan)氫(qing)氨的(de)(de)生成，使(shi)空預器清洗周(zhou)期延長(chang)。