氧(yang)(yang)(yang)是自然(ran)界(jie)分布最廣泛的(de)元(yuan)素之(zhi)一。它以游(you)(you)離狀(zhuang)態和化(hua)(hua)合(he)狀(zhuang)態存(cun)在(zai)(zai)于自然(ran)界(jie)中(zhong)(zhong),空(kong)氣(qi)(qi)(qi)中(zhong)(zhong)游(you)(you)離狀(zhuang)態的(de)氧(yang)(yang)(yang)達20.93%。化(hua)(hua)合(he)狀(zhuang)態的(de)氧(yang)(yang)(yang)存(cun)在(zai)(zai)于水、礦物、植物和動物等物體中(zhong)(zhong)。在(zai)(zai)常(chang)溫及(ji)大(da)氣(qi)(qi)(qi)壓力下(xia),氧(yang)(yang)(yang)為無(wu)色(se)、無(wu)味、無(wu)臭的(de)透明(ming)氣(qi)(qi)(qi)體,比空(kong)氣(qi)(qi)(qi)略(lve)重(zhong)。氧(yang)(yang)(yang)的(de)化(hua)(hua)學性質(zhi)非常(chang)活潑,是強烈的(de)氧(yang)(yang)(yang)化(hua)(hua)劑(ji)和阻(zu)燃(ran)劑(ji)。在(zai)(zai)一般(ban)情(qing)況下(xia),他除了與(yu)(yu)(yu)(yu)(yu)金、銀、鉑(bo)及(ji)惰性氣(qi)(qi)(qi)體不(bu)發(fa)生(sheng)化(hua)(hua)合(he)外,與(yu)(yu)(yu)(yu)(yu)其(qi)他物質(zhi)都能(neng)化(hua)(hua)合(he)生(sheng)成(cheng)氧(yang)(yang)(yang)化(hua)(hua)物,氧(yang)(yang)(yang)與(yu)(yu)(yu)(yu)(yu)其(qi)他物質(zhi)化(hua)(hua)合(he)的(de)過程(cheng)即(ji)為氧(yang)(yang)(yang)化(hua)(hua)反應。氧(yang)(yang)(yang)與(yu)(yu)(yu)(yu)(yu)可燃(ran)氣(qi)(qi)(qi)體如(ru)氫(qing)、乙(yi)炔、甲烷等按(an)一定(ding)比例混(hun)(hun)合(he)后(hou)很容易爆炸。氧(yang)(yang)(yang)經壓縮后(hou)在(zai)(zai)輸送(song)過程(cheng)中(zhong)(zhong)如(ru)有油(you)脂、氧(yang)(yang)(yang)化(hua)(hua)鐵銷及(ji)其(qi)他易燃(ran)物質(zhi)存(cun)在(zai)(zai)時,隨著氣(qi)(qi)(qi)流與(yu)(yu)(yu)(yu)(yu)管(guan)(guan)(guan)壁的(de)摩擦撞(zhuang)擊產生(sheng)大(da)量(liang)摩擦熱,可能(neng)會(hui)導致管(guan)(guan)(guan)道和設備的(de)介質(zhi)燃(ran)燒或爆炸。壓縮氧(yang)(yang)(yang)氣(qi)(qi)(qi)混(hun)(hun)雜有水分,會(hui)使氧(yang)(yang)(yang)氣(qi)(qi)(qi)管(guan)(guan)(guan)道產生(sheng)凝結水,純度越高的(de)氧(yang)(yang)(yang)氣(qi)(qi)(qi)對鋼管(guan)(guan)(guan)的(de)腐蝕越嚴重(zhong)。針(zhen)對氧(yang)(yang)(yang)氣(qi)(qi)(qi)管(guan)(guan)(guan)道的(de)這(zhe)些特點,在(zai)(zai)管(guan)(guan)(guan)道安裝及(ji)維修中(zhong)(zhong)要合(he)理選材,并有相(xiang)應的(de)技術措(cuo)施。


 工(gong)業(ye)生產中使用的氧(yang)氣(qi),一種是由制(zhi)氧(yang)直接用管道(dao)送(song)往(wang)(wang)用戶,一種是在制(zhi)氧(yang)車間以15MPa的高壓充瓶,將瓶裝氧(yang)氣(qi)運往(wang)(wang)用戶。


  氧(yang)氣(qi)管(guan)道修(xiu)理(li)前應(ying)(ying)(ying)將(jiang)修(xiu)理(li)斷與管(guan)網斷開,并(bing)用(yong)(yong)(yong)空氣(qi)、氮氣(qi)或(huo)(huo)(huo)蒸汽將(jiang)氧(yang)氣(qi)全部(bu)趕走置(zhi)(zhi)換,不留死角。修(xiu)理(li)完后(hou)應(ying)(ying)(ying)按照要求進行強度和氣(qi)密性(xing)試驗。試驗合(he)格(ge)(ge)(ge)后(hou),正(zheng)式送(song)氧(yang)前應(ying)(ying)(ying)選用(yong)(yong)(yong)氧(yang)氣(qi)對管(guan)道進行吹(chui)洗(xi),吹(chui)洗(xi)管(guan)道也可應(ying)(ying)(ying)用(yong)(yong)(yong)不含(han)油的壓縮(suo)空氣(qi)或(huo)(huo)(huo)氮氣(qi),氣(qi)流速度不小于20m/s,所(suo)有(you)管(guan)道都應(ying)(ying)(ying)吹(chui)洗(xi)到。在氣(qi)流出口處(chu)用(yong)(yong)(yong)白(bai)紙檢驗,沒有(you)塵粒和水分痕(hen)跡為合(he)格(ge)(ge)(ge)。吹(chui)洗(xi)合(he)格(ge)(ge)(ge)后(hou)再用(yong)(yong)(yong)容(rong)積不少于吹(chui)洗(xi)管(guan)的3倍氧(yang)氣(qi)換管(guan)內的吹(chui)洗(xi)氣(qi)體,且各(ge)個死角都應(ying)(ying)(ying)該(gai)設法(fa)置(zhi)(zhi)換到。只管(guan)管(guan)道的氧(yang)氣(qi)應(ying)(ying)(ying)排至室外,排除(chu)口離(li)地面不少于2.5米,并(bing)應(ying)(ying)(ying)遠離(li)火(huo)(huo)源。輸送(song)含(han)濕氧(yang)的管(guan)道凍(dong)結(jie)時只能(neng)用(yong)(yong)(yong)熱水或(huo)(huo)(huo)蒸汽融(rong)凍(dong),嚴禁(jin)用(yong)(yong)(yong)明火(huo)(huo)融(rong)凍(dong)。


 廠區架(jia)空氧氣管道支(zhi)架(jia),應(ying)采(cai)用非(fei)燃燒(shao)材料制作(zuo),在閥門、排水器及其(qi)他需要檢查維護的地方應(ying)安裝(zhuang)梯子(zi)和平(ping)臺。


 含(han)濕氧(yang)氣管(guan)道,在寒冷地區應(ying)采(cai)取防凍措(cuo)施,防凍措(cuo)施可采(cai)用(yong)敷設保溫(wen)層(ceng)或加伴熱(re)管(guan)。當(dang)采(cai)用(yong)伴熱(re)管(guan)時,伴熱(re)管(guan)的介質應(ying)采(cai)用(yong)不超過90℃熱(re)水。


 地下(xia)鋪設的管子一般(ban)均采(cai)用直(zhi)接埋地鋪設,也可以敷設在填滿(man)沙子的不通(tong)行(xing)(xing)的地溝(gou)內,但禁止氧氣(qi)管道敷設在通(tong)行(xing)(xing)的地溝(gou)內。不通(tong)行(xing)(xing)地溝(gou)應以非燃燒體蓋板,并嚴禁與其他溝(gou)道相通(tong)。直(zhi)接埋地的氧氣(qi)管道應符合下(xia)列要求。


  1. 嚴(yan)禁(jin)氧(yang)氣管道(dao)(dao)通(tong)過煙道(dao)(dao)、通(tong)行地溝和直(zhi)接靠近50℃的熱體表(biao)面。


  2. 嚴禁(jin)氧氣管道與電(dian)(dian)力電(dian)(dian)信電(dian)(dian)纜(lan)、燃氣管(用于同(tong)一(yi)目的的乙炔(gui)管除(chu)外(wai))、燃油管敷設在一(yi)起。


  3. 在腐(fu)蝕(shi)性土壤中敷設(she)的氧(yang)氣管道,外表面應包扎防腐(fu)絕緣層。


  4. 氧氣管道不應埋設在建(jian)筑物、構筑物,露天堆料場的下面(mian)。


  5. 氧氣管(guan)道(dao)(dao)的埋地敷設深(shen)度一般不小于(yu)0.7m,含濕(shi)管(guan)道(dao)(dao)應埋在冰(bing)凍(dong)(dong)線以下,如敷設在冰(bing)凍(dong)(dong)層內時,管(guan)道(dao)(dao)應有防凍(dong)(dong)措施。


  6. 氧氣(qi)管道的閥(fa)門可(ke)直(zhi)接埋(mai)地,但要(yao)設閥(fa)罩,安(an)裝在檢查井內時,井應(ying)單(dan)獨設置,嚴禁其他管道穿越。


  7. 埋地(di)氧氣管道與其他管線(xian)之(zhi)間(jian)的最小凈距離要滿足要求。


  氧(yang)(yang)氣管(guan)(guan)道的選用(yong)在(zai)一(yi)般情況下(xia)以碳(tan)素(su)鋼管(guan)(guan)為主,但由于碳(tan)素(su)鋼管(guan)(guan)在(zai)低(di)溫條件下(xia)(低(di)于-40℃)會變(bian)脆,失去(qu)韌性,也由于其在(zai)純氧(yang)(yang)中易銹蝕,特殊情況下(xia)燃燒,故在(zai)某些管(guan)(guan)路上不用(yong)碳(tan)素(su)鋼管(guan)(guan)而用(yong)不銹鋼管(guan)(guan)、銅(tong)管(guan)(guan)或鋁(lv)合金管(guan)(guan)。此外(wai),氧(yang)(yang)氣管(guan)(guan)道選材時,還應注意以下(xia)幾(ji)點。


  1.  工作壓力超(chao)過1.6MPa的氧氣(qi)管(guan)(guan)道(dao),選用(yong)碳素鋼管(guan)(guan)時,在閥門(men)、流量孔板后需裝一段(duan)長度(du)5倍于管(guan)(guan)道(dao)直徑,且不小于1.5m的等徑銅管(guan)(guan),以免氣(qi)流通過閥門(men)或孔板時產生火花(hua),引起事故。


  2.  調節閥組的管道(dao),不論管徑(jing)或壓力多大,都應采(cai)用不銹鋼管和銅管。


  3. 直接(jie)埋地的氧氣管(guan)道,不(bu)論壓(ya)力高低,均采用無縫(feng)鋼管(guan)。


 4. 溫度低(di)于-40℃的氧(yang)氣管道,無(wu)論壓力高低(di),均應(ying)選(xuan)用(yong)有色金屬(shu)管,以避免由于鋼(gang)管韌性降低(di)變脆而發生(sheng)事故。


  由(you)于氧(yang)(yang)氣(qi)具有阻(zu)燃(ran)的(de)(de)(de)特性,所以氧(yang)(yang)氣(qi)管(guan)道(dao)所用(yong)的(de)(de)(de)一切管(guan)材、管(guan)件、閥(fa)件等(deng)均應進(jin)行(xing)嚴格脫(tuo)脂。由(you)于操作不(bu)當,脫(tuo)脂劑(ji)用(yong)量不(bu)準,使管(guan)道(dao)脫(tuo)脂不(bu)徹底或管(guan)道(dao)中個別附(fu)件進(jin)行(xing)脫(tuo)脂,是(shi)非(fei)常危險。氧(yang)(yang)氣(qi)管(guan)道(dao)或設(she)備爆炸,很多脫(tuo)脂不(bu)徹底造(zao)成(cheng)(cheng)的(de)(de)(de)。管(guan)道(dao)脫(tuo)脂方法見第二章。氧(yang)(yang)氣(qi)管(guan)道(dao)法蘭用(yong)的(de)(de)(de)墊(dian)(dian)片(pian)應無(wu)油脂,并考慮(lv)墊(dian)(dian)片(pian)可能擠壓裂碎掉入管(guan)內,造(zao)成(cheng)(cheng)氧(yang)(yang)氣(qi)管(guan)道(dao)燃(ran)燒(shao),因此不(bu)能選用(yong)易是(shi)燃(ran)材料制成(cheng)(cheng)的(de)(de)(de)墊(dian)(dian)片(pian)。氧(yang)(yang)氣(qi)管(guan)道(dao)輸送的(de)(de)(de)介(jie)質無(wu)論液態或氣(qi)態氧(yang)(yang),均應可靠接地。