Instrument Design
電石爐煙氣凈化及余熱利用技術的開發與應用內(nei)燃(ran)式密(mi)(mi)閉(bi)電石(shi)爐(lu)煙(yan)(yan)氣(qi)特性(xing)(xing)內(nei)燃(ran)式密(mi)(mi)閉(bi)電石(shi)爐(lu)煙(yan)(yan)氣(qi)特性(xing)(xing)內(nei)燃(ran)式密(mi)(mi)閉(bi)電石(shi)爐(lu)煙(yan)(yan)氣(qi)特性(xing)(xing)內(nei)燃(ran)式密(mi)(mi)閉(bi)電石(shi)爐(lu)煙(yan)(yan)氣(qi)特性(xing)(xing) 內(nei)燃(ran)式密(mi)(mi)閉(bi)電石(shi)爐(lu)是(shi)在引(yin)進國外(wai)電石(shi)爐(lu)的基礎上(shang)根據我(wo)國的實際情況自行研(yan)制出來的爐(lu)型,其煙(yan)(yan)溫(wen)及(ji)煙(yan)(yan)氣(qi)量波動較大、粒徑細小(xiao)而且還有一定的粘(zhan)性(xing)(xing),煙(yan)(yan)溫(wen)較高,一般(ban)達到400℃以(yi)上(shang)。 1、國內(nei)內(nei)燃(ran)式密閉電石爐煙氣凈化狀(zhuang)況及(ji)存在的問題 從電(dian)(dian)(dian)石(shi)的(de)(de)粉塵(chen)(chen)(chen)(chen)(chen)(chen)性(xing)(xing)質可(ke)以看(kan)出,電(dian)(dian)(dian)石(shi)爐(lu)(lu)煙氣溫度高,粉塵(chen)(chen)(chen)(chen)(chen)(chen)性(xing)(xing)質復雜,煙氣量大(da),比(bi)電(dian)(dian)(dian)阻高,治理難度是(shi)(shi)(shi)較大(da)的(de)(de)。爐(lu)(lu)氣由于在(zai)爐(lu)(lu)面燃燒(shao),產(chan)生(sheng)的(de)(de)爐(lu)(lu)氣主要成(cheng)(cheng)(cheng)分是(shi)(shi)(shi)CO2和粉塵(chen)(chen)(chen)(chen)(chen)(chen),目(mu)前國內(nei)(nei)用(yong)于內(nei)(nei)燃式密(mi)閉電(dian)(dian)(dian)石(shi)爐(lu)(lu)的(de)(de)凈(jing)化處理方法(fa)中(zhong)有(you)兩種,分別是(shi)(shi)(shi)濕法(fa)除(chu)(chu)(chu)塵(chen)(chen)(chen)(chen)(chen)(chen)和干法(fa)除(chu)(chu)(chu)塵(chen)(chen)(chen)(chen)(chen)(chen),濕法(fa)除(chu)(chu)(chu)塵(chen)(chen)(chen)(chen)(chen)(chen)在(zai)實際使用(yong)過程(cheng)中(zhong)存在(zai)很大(da)的(de)(de)問(wen)題,主要原因(yin)是(shi)(shi)(shi)粉塵(chen)(chen)(chen)(chen)(chen)(chen)中(zhong)含有(you)CaO,遇水生(sheng)成(cheng)(cheng)(cheng)Ca(OH)2,堿性(xing)(xing)、粘(zhan)性(xing)(xing)大(da),在(zai)高溫下形成(cheng)(cheng)(cheng)酸(suan)液嚴重(zhong)腐蝕設(she)備并造(zao)成(cheng)(cheng)(cheng)二次污(wu)染。干法(fa)除(chu)(chu)(chu)塵(chen)(chen)(chen)(chen)(chen)(chen)有(you)旋風(feng)除(chu)(chu)(chu)塵(chen)(chen)(chen)(chen)(chen)(chen)、袋(dai)式除(chu)(chu)(chu)塵(chen)(chen)(chen)(chen)(chen)(chen)和靜電(dian)(dian)(dian)除(chu)(chu)(chu)塵(chen)(chen)(chen)(chen)(chen)(chen),旋風(feng)除(chu)(chu)(chu)塵(chen)(chen)(chen)(chen)(chen)(chen)由于除(chu)(chu)(chu)塵(chen)(chen)(chen)(chen)(chen)(chen)效率低一(yi)般(ban)都(dou)不能達(da)(da)標;靜電(dian)(dian)(dian)除(chu)(chu)(chu)塵(chen)(chen)(chen)(chen)(chen)(chen)要降低粉塵(chen)(chen)(chen)(chen)(chen)(chen)比(bi)電(dian)(dian)(dian)阻,才能夠實現(xian)(xian)(xian)粉塵(chen)(chen)(chen)(chen)(chen)(chen)的(de)(de)達(da)(da)標排放,國內(nei)(nei)目(mu)前能夠實現(xian)(xian)(xian)達(da)(da)標排放的(de)(de)幾乎沒(mei)有(you);布(bu)袋(dai)除(chu)(chu)(chu)塵(chen)(chen)(chen)(chen)(chen)(chen)使用(yong)的(de)(de)比(bi)較普(pu)遍,但在(zai)選用(yong)時要考慮降溫、濾(lv)料和清灰方式的(de)(de)選擇才能實現(xian)(xian)(xian)粉塵(chen)(chen)(chen)(chen)(chen)(chen)的(de)(de)達(da)(da)標排放;相(xiang)比(bi)來說,布(bu)袋(dai)除(chu)(chu)(chu)塵(chen)(chen)(chen)(chen)(chen)(chen)的(de)(de)除(chu)(chu)(chu)塵(chen)(chen)(chen)(chen)(chen)(chen)效率是(shi)(shi)(shi)最高的(de)(de),可(ke)以達(da)(da)到(dao)99%。 多(duo)年來國內(nei)(nei)電(dian)(dian)(dian)石(shi)企(qi)業(ye)和環保科技(ji)(ji)人員(yuan)做(zuo)了(le)大(da)量工作,嘗(chang)試采(cai)用(yong)了(le)各(ge)種除(chu)(chu)(chu)塵(chen)(chen)(chen)(chen)(chen)(chen)技(ji)(ji)術(shu),成(cheng)(cheng)(cheng)功的(de)(de)先例較少。主要存在(zai)的(de)(de)問(wen)題為 ①除塵方式的選(xuan)用不當。 ②整個系統的(de)運行可(ke)靠(kao)性較差,而且影(ying)響電(dian)爐的(de)正(zheng)常生產。 ③采用干法除塵時設備采用的(de)清(qing)灰方式選(xuan)用不當,建議采用新型的(de)高壓噴(pen)管脈(mo)沖清(qing)灰技(ji)術。電石爐的(de)煙(yan)氣特點主(zhu)要(yao)為煙(yan)氣量大(da)、含塵多、粉塵顆(ke)粒(li)細小(xiao)比(bi)重輕且具有一(yi)定的(de)粘(zhan)度(du)、煙(yan)氣溫度(du)較(jiao)高并存在一(yi)定程度(du)的(de)波動。 ④采用(yong)(yong)干法(fa)除(chu)塵(chen)時的(de)濾(lv)料選(xuan)用(yong)(yong)不(bu)(bu)當(dang),由于電(dian)(dian)(dian)石(shi)(shi)爐煙(yan)氣(qi)(qi)(qi)溫(wen)度(du)變化較大,不(bu)(bu)同(tong)的(de)爐型及不(bu)(bu)同(tong)的(de)工(gong)藝狀況其(qi)溫(wen)度(du)不(bu)(bu)同(tong),即使是(shi)同(tong)種爐型在不(bu)(bu)同(tong)的(de)煅燒階段其(qi)溫(wen)度(du)也會有變化,選(xuan)用(yong)(yong)濾(lv)料應(ying)以(yi)煙(yan)氣(qi)(qi)(qi)波(bo)動過程中所達到的(de)最高溫(wen)度(du)來(lai)考(kao)慮,綜(zong)合考(kao)慮是(shi)選(xuan)用(yong)(yong)冷卻系統(tong)+常(chang)溫(wen)濾(lv)料(高溫(wen)濾(lv)料)+除(chu)塵(chen)器或是(shi)無(wu)冷卻系統(tong)直接為(wei)高溫(wen)濾(lv)料+除(chu)塵(chen)器的(de)方式,對電(dian)(dian)(dian)石(shi)(shi)爐的(de)煙(yan)氣(qi)(qi)(qi)溫(wen)度(du)估計不(bu)(bu)足而導致濾(lv)袋燒壞的(de)現象時有發生(sheng)。電(dian)(dian)(dian)石(shi)(shi)爐煙(yan)氣(qi)(qi)(qi)的(de)治理如(ru)此困難(nan),多(duo)年來(lai)電(dian)(dian)(dian)石(shi)(shi)爐煙(yan)氣(qi)(qi)(qi)除(chu)塵(chen)一直是(shi)電(dian)(dian)(dian)石(shi)(shi)行業的(de)一大難(nan)題(ti)。 2內燃(ran)式(shi)密閉電(dian)石爐高(gao)溫煙氣凈化技術(shu)介(jie)紹(shao) 2.1工藝流程 內燃(ran)式密(mi)閉(bi)電石爐(lu)爐(lu)氣(qi)凈(jing)化系統(tong)一般由一個主系統(tong)和四(si)個附屬系統(tong)來組成的. 2.2主(zhu)(zhu)要工(gong)(gong)藝(yi)過程(cheng)說明(ming) 上述(shu)整(zheng)個(ge)工(gong)(gong)藝(yi)流(liu)程(cheng)是采用(yong)余熱利(li)用(yong)或降(jiang)(jiang)溫(wen)(wen)裝(zhuang)置加袋式除塵(chen)(chen)(chen)器(qi)系(xi)統的(de)(de)(de)負(fu)壓(ya)工(gong)(gong)藝(yi)流(liu)程(cheng),具體(ti)為(wei)電石(shi)爐(lu)高(gao)溫(wen)(wen)爐(lu)氣進入專門設(she)計(ji)(ji)的(de)(de)(de)余熱鍋爐(lu)或冷(leng)卻設(she)備(bei)降(jiang)(jiang)溫(wen)(wen),降(jiang)(jiang)至(zhi)200℃左右,然后(hou)經袋除塵(chen)(chen)(chen)器(qi)凈(jing)化(hua)(hua)后(hou)由(you)(you)高(gao)壓(ya)風機排出。整(zheng)個(ge)爐(lu)氣的(de)(de)(de)混合、流(liu)動(dong)均由(you)(you)引風機作(zuo)為(wei)動(dong)力(li)(li)源,整(zheng)個(ge)系(xi)統處于負(fu)壓(ya)狀(zhuang)(zhuang)態(tai)。袋除塵(chen)(chen)(chen)器(qi)采用(yong)高(gao)壓(ya)脈沖噴(pen)吹(chui)進行清(qing)灰(hui)(hui)(hui),當(dang)積聚(ju)在(zai)濾袋外表面(mian)的(de)(de)(de)粉塵(chen)(chen)(chen)達到一定的(de)(de)(de)厚度,清(qing)灰(hui)(hui)(hui)系(xi)統發出清(qing)灰(hui)(hui)(hui)信號,脈沖系(xi)統進行高(gao)壓(ya)清(qing)灰(hui)(hui)(hui),清(qing)灰(hui)(hui)(hui)結束后(hou)又進入正常的(de)(de)(de)過濾狀(zhuang)(zhuang)態(tai)。電石(shi)爐(lu)廢(fei)氣保留旁通(tong)煙道,主(zhu)(zhu)煙道和旁通(tong)煙道用(yong)水(shui)冷(leng)蝶閥進行切換(huan)。整(zheng)個(ge)系(xi)統采用(yong)計(ji)(ji)算機控(kong)制系(xi)統集(ji)(ji)中控(kong)制。除塵(chen)(chen)(chen)器(qi)收(shou)集(ji)(ji)下的(de)(de)(de)粉塵(chen)(chen)(chen)由(you)(you)灰(hui)(hui)(hui)斗和儲灰(hui)(hui)(hui)倉儲存,定時由(you)(you)小車或輸(shu)送設(she)備(bei)輸(shu)送作(zuo)為(wei)建材原料。 系(xi)統中應設(she)置緊(jin)急降(jiang)(jiang)溫(wen)(wen)裝(zhuang)置和旁通(tong)煙道,以自動(dong)或手動(dong)閥門切換(huan)。還可(ke)以考慮將出爐(lu)口煙氣一并考慮由(you)(you)上述(shu)凈(jing)化(hua)(hua)系(xi)統集(ji)(ji)中處理。 上述(shu)整(zheng)個(ge)工(gong)(gong)藝(yi)流(liu)程(cheng)的(de)(de)(de)完成均由(you)(you)一Micropro控(kong)制系(xi)統完成自控(kong)及過程(cheng)中溫(wen)(wen)度壓(ya)力(li)(li)的(de)(de)(de)監測,清(qing)卸(xie)灰(hui)(hui)(hui)的(de)(de)(de)實現,并實行報警功能。 a.每臺電石爐(lu)單獨設向天排(pai)空(kong)的旁通(tong)煙道,并設蝶閥控制; b.每(mei)臺電石爐(lu)單引主煙道用(yong)蝶閥控制; c.當余(yu)熱鍋爐或(huo)冷卻設備降溫至200度左右后進入長袋脈沖除塵器過濾凈化。 d.除塵系統用一臺引(yin)風(feng)機進行抽(chou)引(yin),變(bian)頻控(kong)制,由一根鋼煙囪(cong)排出; 上述主要工藝過(guo)程就是(shi)煙氣(qi)冷卻,凈化設備、清灰裝置、自動控(kong)制系統、旁路系統和報(bao)警裝置組(zu) 2.3關鍵技術(shu) 2.3.1降(jiang)溫技(ji)術 目前國內布袋承(cheng)受的(de)煙氣(qi)(qi)溫度一般(ban)在220℃以下(xia),因此首先(xian)將煙氣(qi)(qi)溫度降(jiang)到220℃以下(xia),然后進行(xing)(xing)布袋除塵,冷(leng)卻(que)方(fang)式常用(yong)空(kong)冷(leng)、水(shui)冷(leng)或加冷(leng)風等(deng)方(fang)法來降(jiang)溫,但這(zhe)些方(fang)法是(shi)不經(jing)濟的(de),最科學的(de)方(fang)法是(shi)對煙氣(qi)(qi)進行(xing)(xing)余(yu)(yu)熱(re)(re)利用(yong)的(de)同時也降(jiang)低(di)煙溫。余(yu)(yu)熱(re)(re)利用(yong)可獲得一定(ding)的(de)經(jing)濟效益,從而(er)改變環保(bao)只投入無產出的(de)情況(kuang)。選擇冷(leng)卻(que)器或者(zhe)余(yu)(yu)熱(re)(re)鍋爐的(de)形式要根據各廠的(de)實(shi)際情況(kuang)來定(ding)。 2.3.2漏風技術問題(ti) 系統中嚴重的(de)漏風,加(jia)快除(chu)塵器的(de)過濾速度,降低除(chu)塵效率,增(zeng)(zeng)加(jia)引(yin)風機(ji)的(de)負(fu)擔,使整個(ge)系統無法正常使用(yong)。降低煙氣溫度,減(jian)少余熱利用(yong)量(liang),增(zeng)(zeng)加(jia)排煙量(liang)。 2.3.3阻(zu)力技術(shu)問題 系統(tong)阻(zu)力過大,會造成(cheng)引風機壓頭(tou)不足,無(wu)法將(jiang)電爐煙氣(qi)全部抽入系統(tong)運行。 2.3.4受熱(re)面(mian)清灰技術(shu)問(wen)題 電石(shi)爐(lu)煙(yan)氣(qi)中含塵量(liang)大而粉塵細(xi)小,很(hen)(hen)容易在管壁、爐(lu)墻上(shang)產生很(hen)(hen)厚(hou)的積塵層(ceng),因此(ci)能(neng)否有效地清除(chu)受熱(re)面(mian)上(shang)的積灰層(ceng),是余熱(re)鍋爐(lu)能(neng)否有效地進(jin)行工(gong)作,回收利用(yong) 煙(yan)氣(qi)余熱(re)產生過熱(re)蒸汽,同時保(bao)證(zheng)(zheng)煙(yan)溫降至200℃左(zuo)右,保(bao)證(zheng)(zheng)布(bu)袋除(chu)塵器安(an)全工(gong)作的關鍵。 2.3.5控(kong)制(zhi)系(xi)統(tong)(tong)(tong) 控(kong)制(zhi)系(xi)統(tong)(tong)(tong)由計算機、PLC、顯示器、操作(zuo)箱(xiang)溫(wen)壓(ya)儀(yi)表等組成;采用定時(shi)、定阻聯合(he)清灰(hui)設計;停機自(zi)清灰(hui)系(xi)統(tong)(tong)(tong);提供(gong)煙(yan)氣(qi)超溫(wen)放風報警系(xi)統(tong)(tong)(tong)及主(zhu)旁通煙(yan)道(dao)(dao)自(zi)動(dong)切換系(xi)統(tong)(tong)(tong);提供(gong)除塵器進出口溫(wen)度和壓(ya)差顯示;獨(du)立(li)卸(xie)灰(hui)輸送控(kong)制(zhi)系(xi)統(tong)(tong)(tong)及卸(xie)灰(hui)系(xi)統(tong)(tong)(tong)連鎖(suo)開(kai)啟控(kong)制(zhi);提供(gong)穩定爐面負壓(ya)的自(zi)動(dong)控(kong)制(zhi);提供(gong)主(zhu)煙(yan)道(dao)(dao)和旁通煙(yan)道(dao)(dao)切換閥的電動(dong)操作(zuo)及開(kai)度顯示; 內(nei)燃式密閉電石爐煙(yan)氣溫度(du)變(bian)(bian)化幅(fu)度(du)很(hen)(hen)大(da)(da),平均溫度(du)500℃,高(gao)時連續在600℃以(yi)上,這對(dui)冷(leng)(leng)卻設備的(de)(de)受熱面布(bu)置和(he)排煙(yan)溫度(du)的(de)(de)控制(zhi)帶來很(hen)(hen)大(da)(da)的(de)(de)困難,也給后(hou)面的(de)(de)除塵(chen)器濾料帶來很(hen)(hen)大(da)(da)的(de)(de)沖擊,對(dui)整個系統的(de)(de)安全帶來隱患(huan),因(yin)此必(bi)須(xu)有(you)可靠的(de)(de)溫控技(ji)術(shu)和(he)經濟安全措施作(zuo)為安全運行的(de)(de)保證。所以(yi)設計(ji)的(de)(de)冷(leng)(leng)卻裝(zhuang)置和(he)余(yu)熱鍋(guo)爐必(bi)須(xu)適應比(bi)較大(da)(da)的(de)(de)溫度(du)變(bian)(bian)化范圍,同(tong)時要有(you)溫控裝(zhuang)置控制(zhi)排煙(yan)溫度(du)幅(fu)度(du)在30℃左右(you),另外還加有(you)緊急自動(dong)進冷(leng)(leng)風裝(zhuang)置。 2.3.6除(chu)灰(hui)外(wai)運(yun)系統 除(chu)灰(hui)外(wai)運(yun)系統是保(bao)證(zheng)除(chu)塵器除(chu)灰(hui)與飛灰(hui)外(wai)運(yun)中無二(er)次污染設(she)計(ji)的,飛灰(hui)比重輕,容易造成二(er)次污染,應采用密封輸送,封閉型集灰(hui)箱裝運(yun)飛灰(hui)的系統,以(yi)確保(bao)無二(er)次污染。 2.4余(yu)熱(re)綜合利用(yong) 對(dui)(dui)于密封好的(de)內燃式(shi)密閉(bi)電石(shi)爐(lu)(lu)爐(lu)(lu)氣溫度可到600℃左右,其熱(re)量(liang)還是有很大的(de)利用(yong)價值,針對(dui)(dui)不同的(de)用(yong)戶可選(xuan)擇(ze)烘干焦碳或余(yu)熱(re)鍋爐(lu)(lu)產蒸(zheng)汽的(de)方式(shi)。爐(lu)(lu)氣中熱(re)量(liang)的(de)利用(yong),可以(yi)達到更高(gao)的(de)經濟效(xiao)益、環保效(xiao)益和社會效(xiao)益,開(kai)創三豐收(shou)的(de)局面(mian).
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