氧(yang)(yang)(yang)分(fen)析(xi)儀(yi)(yi)是一(yi)種(zhong)工(gong)業過程(cheng)(cheng)分(fen)析(xi)儀(yi)(yi)表(biao),主要用于各種(zhong)工(gong)業過程(cheng)(cheng)混合(he)氣體(ti)(ti)中氧(yang)(yang)(yang)含量檢(jian)測。多應用于石油、空分(fen)、化工(gong)流程(cheng)(cheng)、磁性材(cai)料、高溫燒結爐保(bao)護氣體(ti)(ti)、電子行(xing)(xing)業保(bao)護性氣體(ti)(ti)以(yi)及玻璃、建材(cai)行(xing)(xing)業等行(xing)(xing)業。根據(ju)不(bu)同(tong)的(de)工(gong)況工(gong)藝,有不(bu)同(tong)原(yuan)理的(de)氧(yang)(yang)(yang)分(fen)析(xi)儀(yi)(yi),具體(ti)(ti)分(fen)為電化學式氧(yang)(yang)(yang)分(fen)析(xi)儀(yi)(yi)(又名燃料電池法氧(yang)(yang)(yang)分(fen)析(xi)儀(yi)(yi))、氧(yang)(yang)(yang)化鋯氧(yang)(yang)(yang)分(fen)析(xi)儀(yi)(yi)、磁氧(yang)(yang)(yang)分(fen)析(xi)儀(yi)(yi)(又名順磁氧(yang)(yang)(yang)分(fen)析(xi)儀(yi)(yi))、激光式氧(yang)(yang)(yang)分(fen)析(xi)儀(yi)(yi),不(bu)同(tong)原(yuan)理的(de)氧(yang)(yang)(yang)分(fen)析(xi)儀(yi)(yi),各自(zi)有著不(bu)同(tong)的(de)優缺點。
一、電化學氧分析儀
電(dian)(dian)(dian)化學氧(yang)(yang)氣(qi)分析儀的(de)(de)(de)的(de)(de)(de)核(he)心元件是一(yi)個(ge)(ge)(ge)電(dian)(dian)(dian)化學氧(yang)(yang)氣(qi)傳(chuan)感(gan)(gan)器(qi)。常見(jian)的(de)(de)(de)電(dian)(dian)(dian)化學氧(yang)(yang)氣(qi)傳(chuan)感(gan)(gan)器(qi)由一(yi)個(ge)(ge)(ge)傳(chuan)感(gan)(gan)電(dian)(dian)(dian)極(ji)(ji)(或工作電(dian)(dian)(dian)極(ji)(ji))和一(yi)個(ge)(ge)(ge)對電(dian)(dian)(dian)極(ji)(ji)組(zu)成(cheng),兩(liang)個(ge)(ge)(ge)電(dian)(dian)(dian)極(ji)(ji)間(jian)(jian)有(you)一(yi)層薄(bo)薄(bo)的(de)(de)(de)電(dian)(dian)(dian)解液(ye)。要檢測(ce)(ce)的(de)(de)(de)氣(qi)體先(xian)通(tong)過(guo)一(yi)個(ge)(ge)(ge)小(xiao)的(de)(de)(de)毛細口傳(chuan)感(gan)(gan)器(qi),然后通(tong)過(guo)一(yi)個(ge)(ge)(ge)疏(shu)水膜(mo)(mo)擴散進入(ru)(ru),終到達(da)電(dian)(dian)(dian)極(ji)(ji)表面。傳(chuan)感(gan)(gan)器(qi)的(de)(de)(de)結(jie)構設(she)計保(bao)證會(hui)有(you)適量的(de)(de)(de)氣(qi)體進入(ru)(ru)與感(gan)(gan)應(ying)(ying)電(dian)(dian)(dian)極(ji)(ji)反應(ying)(ying)產生(sheng)(sheng)足夠(gou)的(de)(de)(de)電(dian)(dian)(dian)信號,并同時(shi)防止(zhi)電(dian)(dian)(dian)解液(ye)泄(xie)漏(lou)出(chu)傳(chuan)感(gan)(gan)器(qi)。通(tong)過(guo)疏(shu)水膜(mo)(mo)擴散進入(ru)(ru)傳(chuan)感(gan)(gan)器(qi)里的(de)(de)(de)氣(qi)體在感(gan)(gan)應(ying)(ying)電(dian)(dian)(dian)極(ji)(ji)發生(sheng)(sheng)氧(yang)(yang)化/還(huan)原反應(ying)(ying),電(dian)(dian)(dian)極(ji)(ji)間(jian)(jian)連(lian)接一(yi)個(ge)(ge)(ge)電(dian)(dian)(dian)阻,這樣,陰極(ji)(ji)和陽(yang)極(ji)(ji)間(jian)(jian)會(hui)產生(sheng)(sheng)一(yi)個(ge)(ge)(ge)與氧(yang)(yang)濃(nong)(nong)度(du)成(cheng)正比的(de)(de)(de)電(dian)(dian)(dian)流(liu)。通(tong)過(guo)檢測(ce)(ce)這個(ge)(ge)(ge)電(dian)(dian)(dian)流(liu),就反應(ying)(ying)出(chu)氣(qi)體中的(de)(de)(de)氧(yang)(yang)濃(nong)(nong)度(du)。
電化學氧分析儀優點:
· 相對來說通用性好
· 價格適中
· 測量精度(du)、準(zhun)確的(de)都不錯
電化學氧分析儀缺點:
· 傳感器(qi)壽命短(化(hua)學原理(li)有(you)消耗性)
· 傳感(gan)器容易受其他氣體影響(如腐蝕性氣體)
二、氧化鋯氧分析儀
氧(yang)化鋯(gao)(ZrO2)是一種陶瓷,一種具有(you)離子(zi)導電性質的固(gu)體。在常溫(wen)(wen)下為(wei)單斜 晶體,當溫(wen)(wen)度(du)升高到一定溫(wen)(wen)度(du)時,晶型轉變(bian)為(wei)立方(fang)晶體,同時約有(you) 7%的體積(ji)收(shou) 縮;當溫(wen)(wen)度(du)降低時,又變(bian)為(wei)單斜晶體。若反復加熱與冷卻,ZrO2 就(jiu)會破裂。
因 此,純凈(jing)的(de)(de)(de) ZrO2 不能用作(zuo)測量(liang)元件。如果(guo)在 ZrO2 中加入一定量(liang)的(de)(de)(de)氧化鈣(gai)(CaO) 或氧化釔(Y2O3)作(zuo)穩定劑,再經過(guo)高溫焙燒,則變為穩定的(de)(de)(de)氧化鋯(gao)材(cai)料,這(zhe) 時,四價的(de)(de)(de)鋯(gao)被二價的(de)(de)(de)鈣(gai)或三價的(de)(de)(de)釔置(zhi)換,同時產生氧離子空穴(xue),所以 ZrO2 屬(shu)于陰離子固體(ti)電解質(zhi)。ZrO2 主要通過(guo)空穴(xue)的(de)(de)(de)運動(dong)而導電,當(dang)溫度達(da)到 600℃ 以上時,ZrO2 就變為良好的(de)(de)(de)氧離子導體(ti)。
在氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化鋯(gao)電(dian)(dian)解質的(de)(de)兩面各燒結(jie)一個鉑(bo)電(dian)(dian)極(ji)(ji),當氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化鋯(gao)兩側的(de)(de)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)分壓不同時(shi), 氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)分壓高(gao)的(de)(de)一側的(de)(de)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)以離子(zi)形(xing)式向氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)分壓低的(de)(de)一側遷移,結(jie)果使(shi)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)分壓高(gao)的(de)(de)一 側鉑(bo)電(dian)(dian)極(ji)(ji)失去電(dian)(dian)子(zi)顯正電(dian)(dian),而(er)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)分壓低的(de)(de)一側鉑(bo)電(dian)(dian)極(ji)(ji)得到電(dian)(dian)子(zi)顯負電(dian)(dian),因而(er)在 兩鉑(bo)電(dian)(dian)極(ji)(ji)之間產生(sheng)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)濃(nong)(nong)差(cha)電(dian)(dian)勢(shi)。此(ci)電(dian)(dian)勢(shi)在溫度一定時(shi)只與(yu)兩側氣(qi)體中(zhong)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)含量(liang) 的(de)(de)差(cha)(氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)濃(nong)(nong)差(cha))有(you)關。若(ruo)一側氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)含量(liang)已(yi)知(zhi)(zhi)(如(ru)空氣(qi)中(zhong)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)含量(liang)為(wei)常數),則另 一側氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)含量(liang)(如(ru)煙(yan)氣(qi)中(zhong)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)含量(liang))就可用氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)濃(nong)(nong)差(cha)電(dian)(dian)勢(shi)表示,測出氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)濃(nong)(nong)差(cha)電(dian)(dian)勢(shi), 便可知(zhi)(zhi)道煙(yan)氣(qi)中(zhong)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)含量(liang)。
因為(wei)氧(yang)化鋯的(de)耐高溫特性,多應用于溫度條件相對較高的(de)工況(窯爐(lu)、鍋爐(lu))
氧化鋯氧分析儀優點:
· 不受檢(jian)測氣體溫度的影響(氧化鋯氧量分析儀耐(nai)高(gao)溫)
· 通(tong)過(guo)不同導(dao)流管(guan)可檢測各種(zhong)溫(wen)度氣體中的氧(yang)含量
· 適用于溫度(du)較高的工況
氧化鋯氧分析儀缺點:
· 采樣(yang)氣體雜質(zhi)較多時(shi),有可能(neng)堵(du)塞采樣(yang)管
· 多孔鉑電極易受到被測氣(qi)體(ti)中的腐蝕性氣(qi)體(ti)腐蝕而失效
· 加熱器一般用電爐(lu)絲加熱,壽命(ming)不長
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