-
- 電加熱導熱油爐常見的事故隱患及處理措施
- 發布日期:2019年12月11 點擊次數:78 所屬分類:常見問題
1、導(dao)熱油品質下降的(de)隱(yin)患
因生(sheng)產工藝操作管(guan)(guan)理不(bu)(bu)善而(er)導(dao)致(zhi)的導(dao)熱(re)(re)(re)(re)油(you)(you)品質(zhi)(zhi)過早變質(zhi)(zhi),是(shi)(shi)電加熱(re)(re)(re)(re)導(dao)熱(re)(re)(re)(re)油(you)(you)爐(lu)最容易發(fa)(fa)生(sheng)的問題之一,有些(xie)導(dao)熱(re)(re)(re)(re)油(you)(you)僅(jin)僅(jin)使(shi)(shi)用一兩年,性(xing)(xing)能(neng)指(zhi)標(biao)就嚴重(zhong)劣(lie)(lie)化(hua)(hua)(hua)。而(er)長期(qi)運行(xing)劣(lie)(lie)質(zhi)(zhi)的導(dao)熱(re)(re)(re)(re)油(you)(you),受熱(re)(re)(re)(re)面管(guan)(guan)壁積(ji)碳不(bu)(bu)斷增加,管(guan)(guan)內徑縮(suo)(suo)小(xiao)使(shi)(shi)導(dao)熱(re)(re)(re)(re)油(you)(you)流量(liang)不(bu)(bu)斷降低(di)(di),循環泵阻力逐步增大(da),傳熱(re)(re)(re)(re)效率(lv)持續降低(di)(di),進(jin)而(er)導(dao)致(zhi)爐(lu)管(guan)(guan)內結焦、堵(du)塞,最終發(fa)(fa)生(sheng)過燒、變形、爆(bao)管(guan)(guan)等惡(e)性(xing)(xing)事(shi)故。 造成(cheng)導(dao)熱(re)(re)(re)(re)油(you)(you)品質(zhi)(zhi)下降的原因之一是(shi)(shi)局部(bu)過熱(re)(re)(re)(re)發(fa)(fa)生(sheng)熱(re)(re)(re)(re)裂解,二是(shi)(shi)導(dao)熱(re)(re)(re)(re)油(you)(you)氧(yang)化(hua)(hua)(hua)。導(dao)熱(re)(re)(re)(re)油(you)(you)超過其規定的最高(gao)使(shi)(shi)用溫度(du)便會局部(bu)過熱(re)(re)(re)(re),產生(sheng)熱(re)(re)(re)(re)分解和縮(suo)(suo)聚,析出殘(can)碳,閃(shan)(shan)點下降,顏(yan)色(se)變深,黏度(du)增大(da),傳熱(re)(re)(re)(re)效率(lv)下降,結焦老化(hua)(hua)(hua)。導(dao)熱(re)(re)(re)(re)油(you)(you)與(yu)空氣中的氧(yang)氣接(jie)觸發(fa)(fa)生(sheng)氧(yang)化(hua)(hua)(hua)反應,生(sheng)成(cheng)有機(ji)酸并縮(suo)(suo)聚成(cheng)膠(jiao)泥,使(shi)(shi)黏度(du)增加,不(bu)(bu)僅(jin)降低(di)(di)介(jie)質(zhi)(zhi)的使(shi)(shi)用壽(shou)命,而(er)且造成(cheng)系統酸性(xing)(xing)腐蝕。 目前國(guo)內各(ge)導(dao)熱(re)(re)(re)(re)油(you)(you)廠制定的質(zhi)(zhi)量(liang)標(biao)準(zhun)各(ge)自不(bu)(bu)同,生(sheng)產的導(dao)熱(re)(re)(re)(re)油(you)(you)質(zhi)(zhi)量(liang)也(ye)差異較大(da),對于使(shi)(shi)用中的導(dao)熱(re)(re)(re)(re)油(you)(you),《有機(ji)熱(re)(re)(re)(re)載體爐(lu)安全技(ji)術監察(cha)規程(cheng)》規定每年對運動粘度(du)、閃(shan)(shan)點、殘(can)碳、酸值(zhi)至少檢測一次。
2、自動控制系統失效的(de)隱(yin)患
當前,國內導熱(re)(re)(re)油(you)電加(jia)熱(re)(re)(re)器(qi)(qi)(qi)工藝的(de)現狀是(shi)導熱(re)(re)(re)油(you)控制系(xi)統以可編程序控制器(qi)(qi)(qi)控制PLC為控制核心,對一定溫(wen)度(du)的(de)導熱(re)(re)(re)油(you),在循環泵(beng)的(de)工作壓力下從(cong)(cong)加(jia)熱(re)(re)(re)器(qi)(qi)(qi)的(de)進口(kou)進入,導熱(re)(re)(re)油(you)通(tong)過加(jia)熱(re)(re)(re)器(qi)(qi)(qi)發熱(re)(re)(re)腔使溫(wen)度(du)逐步(bu)升高,然后從(cong)(cong)出口(kou)流出,從(cong)(cong)而(er)導熱(re)(re)(re)油(you)達到所需(xu)的(de)工藝溫(wen)度(du),使得(de)設(she)備的(de)自動化程度(du)得(de)到進一步(bu)提高。
在控(kong)制系統(tong)中導熱(re)油(you)經過(guo)齒輪泵送入(ru)整(zheng)個系統(tong)中,當設(she)定(ding)好的磁性(xing)翻(fan)柱式液(ye)位(wei)控(kong)制器到達指(zhi)定(ding)液(ye)位(wei)時,齒輪泵自動關(guan)閉,這時啟動循環泵和電加(jia)熱(re)器開始加(jia)熱(re),當出口油(you)溫達到設(she)定(ding)值時,進入(ru)用(yong)戶(hu)系統(tong)循環,經設(she)備(bei)使用(yong)后的油(you)再次進入(ru)裝置加(jia)熱(re),周(zhou)而復始,循環運轉,即為導熱(re)油(you)的工作狀態。
這些自動控制系統是保證電(dian)加熱導熱油爐安全(quan)運行的(de)(de)有效關卡,而往往就(jiu)是這些關卡,在實際運行中常由于安全(quan)意識的(de)(de)薄(bo)弱或經濟(ji)方面的(de)(de)原因而失效。
3、空(kong)氣和水分進入的(de)隱患
在(zai)電加(jia)熱(re)(re)(re)導(dao)(dao)熱(re)(re)(re)油爐新加(jia)油、換(huan)油和維修(xiu)過程(cheng)中(zhong)易進入空氣和水(shui)(shui)(shui)(shui)分(fen)(fen)(fen),在(zai)加(jia)溫(wen)過程(cheng)中(zhong)這些空氣膨脹(zhang)、水(shui)(shui)(shui)(shui)分(fen)(fen)(fen)蒸發,其體(ti)積的(de)(de)變(bian)化(hua)遠(yuan)遠(yuan)超過了(le)導(dao)(dao)熱(re)(re)(re)油自身(shen)熱(re)(re)(re)膨脹(zhang)量,相對壓力為零時,水(shui)(shui)(shui)(shui)蒸發時體(ti)積膨脹(zhang)約(yue)是其原來的(de)(de)1600多倍,空氣在(zai)升(sheng)溫(wen)270℃的(de)(de)情(qing)況下約(yue)膨脹(zhang)5倍。這些空氣和水(shui)(shui)(shui)(shui)分(fen)(fen)(fen)如(ru)果不能及時得到排(pai)放,必將引起(qi)運行(xing)壓力提(ti)高(gao),嚴重威脅系統(tong)安全(quan)。因此(ci),應嚴格(ge)控(kong)(kong)制(zhi)導(dao)(dao)熱(re)(re)(re)油中(zhong)的(de)(de)水(shui)(shui)(shui)(shui)分(fen)(fen)(fen)及其他組分(fen)(fen)(fen)。在(zai)加(jia)熱(re)(re)(re)啟動過程(cheng)中(zhong)要反復打開排(pai)氣閥,以排(pai)凈系統(tong)中(zhong)的(de)(de)空氣、水(shui)(shui)(shui)(shui)與導(dao)(dao)熱(re)(re)(re)油混(hun)合蒸汽,并注意控(kong)(kong)制(zhi)導(dao)(dao)熱(re)(re)(re)油升(sheng)溫(wen)速(su)度。
4、 管(guan)道(dao)法蘭(lan)或閥門(men)間的(de)泄漏隱患
管(guan)道法(fa)蘭(lan)或閥(fa)(fa)門連接(jie)處(chu)是導(dao)熱油(you)系統最易(yi)(yi)(yi)(yi)發生泄漏(lou)的部(bu)位,由(you)于導(dao)熱油(you)具有易(yi)(yi)(yi)(yi)滲透、易(yi)(yi)(yi)(yi)燃(ran)燒的特性(xing),尤(you)其是對多(duo)孔材料制成(cheng)的保溫(wen)(wen)(wen)層(ceng)浸附性(xing)更強(qiang)。如(ru)果導(dao)熱油(you)一旦發生泄漏(lou)而(er)沒能及時(shi)發現(xian),很(hen)容(rong)易(yi)(yi)(yi)(yi)引發火災(zai)。因此(ci),必須定期檢查法(fa)蘭(lan)和(he)(he)閥(fa)(fa)門連接(jie)處(chu)的完好情況,如(ru)有損壞應及時(shi)更換。從導(dao)熱油(you)爐停(ting)用(yong)到(dao)運行過程,由(you)于溫(wen)(wen)(wen)度變(bian)化大(da),法(fa)蘭(lan)間易(yi)(yi)(yi)(yi)松動,常有滲漏(lou)現(xian)象,這時(shi)應引起重視。管(guan)道系統中所有密(mi)封件(jian)應選用(yong)具有良好密(mi)封性(xing)和(he)(he)阻燃(ran)性(xing)的柔性(xing)和(he)(he)金屬(shu)纏(chan)繞制品,切忌用(yong)含有橡膠成(cheng)分(fen)的密(mi)封件(jian)。保溫(wen)(wen)(wen)材料應采(cai)用(yong)空隙度小(xiao)且不易(yi)(yi)(yi)(yi)受有機熱載(zai)體浸漬(zi)的材料,以防有機熱載(zai)體泄漏(lou)后造成(cheng)保溫(wen)(wen)(wen)層(ceng)著火。
5、電加(jia)熱棒結焦炭化的(de)隱患
用(yong)電(dian)(dian)(dian)熱(re)(re)(re)棒(bang)(bang)(bang)加熱(re)(re)(re)導(dao)熱(re)(re)(re)油(you)(you)時,電(dian)(dian)(dian)熱(re)(re)(re)棒(bang)(bang)(bang)表(biao)(biao)(biao)面(mian)會很快(kuai)結(jie)焦炭(tan)化,最終使電(dian)(dian)(dian)熱(re)(re)(re)捧(peng)燒毀,導(dao)熱(re)(re)(re)油(you)(you)報廢。造成嚴重(zhong)(zhong)積炭(tan)的(de)(de)原因可(ke)通(tong)過(guo)傳(chuan)熱(re)(re)(re)計算來分析:從市(shi)場上購來的(de)(de)220V4kW電(dian)(dian)(dian)熱(re)(re)(re)棒(bang)(bang)(bang)表(biao)(biao)(biao)面(mian)積為(wei)0.125m2,在自然(ran)對流(liu)狀(zhuang)態下傳(chuan)熱(re)(re)(re)系(xi)數K=67~114W/℃·m2,取大(da)(da)值K=114W/℃·m2。根(gen)據Q=KF△t計算可(ke)知(zhi),電(dian)(dian)(dian)熱(re)(re)(re)棒(bang)(bang)(bang)要傳(chuan)給(gei)導(dao)熱(re)(re)(re)油(you)(you)4 kW熱(re)(re)(re)量,棒(bang)(bang)(bang)表(biao)(biao)(biao)面(mian)與導(dao)熱(re)(re)(re)油(you)(you)的(de)(de)溫(wen)(wen)(wen)差(cha)必須大(da)(da)于(yu)(yu)275℃。當導(dao)熱(re)(re)(re)油(you)(you)平均(jun)溫(wen)(wen)(wen)度(du)為(wei)300℃時,棒(bang)(bang)(bang)表(biao)(biao)(biao)面(mian)溫(wen)(wen)(wen)度(du)必須達(da)575℃。而最高(gao)允許(xu)(xu)使用(yong)溫(wen)(wen)(wen)度(du)為(wei)340℃的(de)(de)導(dao)熱(re)(re)(re)油(you)(you)在加熱(re)(re)(re)爐管中的(de)(de)允許(xu)(xu)膜(mo)溫(wen)(wen)(wen)(相當于(yu)(yu)這里的(de)(de)棒(bang)(bang)(bang)表(biao)(biao)(biao)面(mian)溫(wen)(wen)(wen)度(du))不得超過(guo)370℃。現在導(dao)熱(re)(re)(re)油(you)(you)與575℃的(de)(de)棒(bang)(bang)(bang)表(biao)(biao)(biao)面(mian)接觸,結(jie)焦炭(tan)化肯定是(shi)嚴重(zhong)(zhong)的(de)(de),導(dao)熱(re)(re)(re)油(you)(you)的(de)(de)壽命也很短。 防止在電(dian)(dian)(dian)熱(re)(re)(re)棒(bang)(bang)(bang)表(biao)(biao)(biao)面(mian)嚴重(zhong)(zhong)積炭(tan)的(de)(de)途徑是(shi)增(zeng)加電(dian)(dian)(dian)熱(re)(re)(re)棒(bang)(bang)(bang)的(de)(de)表(biao)(biao)(biao)面(mian)積,使棒(bang)(bang)(bang)表(biao)(biao)(biao)面(mian)熱(re)(re)(re)負荷限定在適當范圍(wei)內。通(tong)過(guo)計算將4kW 電(dian)(dian)(dian)熱(re)(re)(re)棒(bang)(bang)(bang)中并聯的(de)(de)兩根(gen)2kW 電(dian)(dian)(dian)阻絲(si)改接成串聯,端電(dian)(dian)(dian)壓為(wei)220V 時,電(dian)(dian)(dian)阻絲(si)的(de)(de)總功率為(wei)1 kW。電(dian)(dian)(dian)熱(re)(re)(re)捧(peng)表(biao)(biao)(biao)面(mian)積仍為(wei)0.125m2,傳(chuan)熱(re)(re)(re)所需溫(wen)(wen)(wen)差(cha)為(wei)69℃。同(tong)樣,平均(jun)油(you)(you)溫(wen)(wen)(wen)為(wei)300℃時, 電(dian)(dian)(dian)熱(re)(re)(re)棒(bang)(bang)(bang)表(biao)(biao)(biao)面(mian)溫(wen)(wen)(wen)度(du)為(wei)369℃即可(ke),將1 kW 熱(re)(re)(re)量傳(chuan)給(gei)導(dao)熱(re)(re)(re)油(you)(you)。369℃已接近導(dao)熱(re)(re)(re)油(you)(you)允許(xu)(xu)的(de)(de)膜(mo)溫(wen)(wen)(wen)370℃,有(you)可(ke)能使結(jie)焦問題得到緩(huan)解。最好(hao)的(de)(de)解決方法是(shi)專(zhuan)門設計制造專(zhuan)用(yong)的(de)(de)電(dian)(dian)(dian)熱(re)(re)(re)棒(bang)(bang)(bang),增(zeng)大(da)(da)表(biao)(biao)(biao)面(mian)積,使捧(peng)表(biao)(biao)(biao)面(mian)溫(wen)(wen)(wen)度(du)低于(yu)(yu)導(dao)熱(re)(re)(re)油(you)(you)的(de)(de)允許(xu)(xu)液(ye)膜(mo)溫(wen)(wen)(wen)度(du)。
6、結語(yu)
總之,由于電加(jia)熱(re)導熱(re)油爐(lu)所使用的導熱(re)油介質具有(you)易(yi)(yi)滲漏、易(yi)(yi)燃燒的特性(xing),若對(dui)其介質特殊性(xing)和(he)操(cao)作安全性(xing)認識不夠(gou),在運行(xing)中極易(yi)(yi)發生(sheng)泄漏和(he)火(huo)災、爆炸(zha)等事故(gu),而識別了其常見的事故(gu)隱患并(bing)有(you)針對(dui)性(xing)地采取(qu)預防措施即可大大降低電加(jia)熱(re)導熱(re)油爐(lu)發生(sheng)火(huo)災事故(gu)的風險(xian)。
- 相關標簽:常見問題
-
上一篇:法蘭電熱管遇到發黑問題應當如何
下一篇:防爆管道加熱器的機械應用和維護