閃點實驗原理

1、閃點的定義

在(zai)規定條(tiao)件下，石油產(chan)品(pin)(pin)受熱后，所產(chan)生(sheng)的(de)油蒸(zheng)氣(qi)(qi)與周圍空氣(qi)(qi)形成(cheng)的(de)混合氣(qi)(qi)體，在(zai)遇到明火時，發生(sheng)瞬間(jian)著火(閃(shan)火現(xian)象(xiang))時的(de)zui低溫度，稱為該石油產(chan)品(pin)(pin)的(de)閃(shan)點(dian)或閃(shan)火點(dian)。

2、閃點的測定原理

由于(yu)(yu)(yu)使(shi)(shi)(shi)用(yong)(yong)(yong)(yong)(yong)石油(you)(you)產品(pin)(pin)(pin)(pin)是有(you)封閉狀態(tai)和(he)暴露狀態(tai)的區別,測定閃(shan)點的方法(fa)(fa)有(you)閉口(kou)杯法(fa)(fa)和(he)開(kai)口(kou)杯法(fa)(fa)兩(liang)種。閉口(kou)杯法(fa)(fa)多用(yong)(yong)(yong)(yong)(yong)于(yu)(yu)(yu)輕質油(you)(you)品(pin)(pin)(pin)(pin)，開(kai)口(kou)杯法(fa)(fa)多用(yong)(yong)(yong)(yong)(yong)于(yu)(yu)(yu)潤滑(hua)(hua)(hua)及(ji)(ji)重質油(you)(you)品(pin)(pin)(pin)(pin)。具體(ti)如何選用(yong)(yong)(yong)(yong)(yong)則取(qu)決于(yu)(yu)(yu)油(you)(you)樣的性質和(he)使(shi)(shi)(shi)用(yong)(yong)(yong)(yong)(yong)條件(jian)。輕質油(you)(you)品(pin)(pin)(pin)(pin)選用(yong)(yong)(yong)(yong)(yong)閉口(kou)杯閃(shan)點是由于(yu)(yu)(yu)它與(yu)輕質油(you)(you)品(pin)(pin)(pin)(pin)的實際儲存(cun)和(he)使(shi)(shi)(shi)用(yong)(yong)(yong)(yong)(yong)條件(jian)相似，可以作為(wei)安全防火控(kong)(kong)制指(zhi)標的依據。重質油(you)(you)品(pin)(pin)(pin)(pin)及(ji)(ji)多數潤滑(hua)(hua)(hua)油(you)(you)，一般在非密閉機件(jian)或溫度不(bu)高的條件(jian)下(xia)使(shi)(shi)(shi)用(yong)(yong)(yong)(yong)(yong)，他們含輕質組分較少，因此采用(yong)(yong)(yong)(yong)(yong)開(kai)口(kou)杯法(fa)(fa)測定。對于(yu)(yu)(yu)在密閉，高溫條件(jian)下(xia)使(shi)(shi)(shi)用(yong)(yong)(yong)(yong)(yong)的內燃機潤滑(hua)(hua)(hua)油(you)(you)、特種潤滑(hua)(hua)(hua)油(you)(you)、電器用(yong)(yong)(yong)(yong)(yong)油(you)(you)則要(yao)求(qiu)控(kong)(kong)制閉口(kou)杯焊點。

測(ce)定閃(shan)(shan)點(dian)(dian)時，將試(shi)(shi)油裝入油杯(bei)，在(zai)規定條件下加熱(re)(re)蒸發，控制升溫速度(du)，在(zai)達到預期閃(shan)(shan)點(dian)(dian)溫度(du)qian 10℃時，每(mei)間隔(ge)一定的(de)(de)溫度(du)，按(an)規定的(de)(de)方式，進(jin)行點(dian)(dian)火(huo)試(shi)(shi)驗(yan)，直至出現閃(shan)(shan)火(huo)現象，即發生閃(shan)(shan)火(huo)現象的(de)(de)zui低(di)溫度(du)為試(shi)(shi)油的(de)(de)閃(shan)(shan)點(dian)(dian)。閉口杯(bei)法(fa)和開(kai)口杯(bei)法(fa)的(de)(de)區別(bie)是儀(yi)器不同(tong)、加熱(re)(re)和引火(huo)條件不同(tong)。閉口杯(bei)法(fa)中(zhong)試(shi)(shi)油在(zai)密閉油杯(bei)中(zhong)加熱(re)(re)，只(zhi)在(zai)點(dian)(dian)火(huo)的(de)(de)瞬間才(cai)打開(kai)杯(bei)蓋;開(kai)口杯(bei)法(fa)中(zhong)試(shi)(shi)油是在(zai)敞開(kai)杯(bei)中(zhong)加熱(re)(re)，蒸發的(de)(de)油氣可以白由(you)向空(kong)氣中(zhong)擴散，測(ce)得的(de)(de)閃(shan)(shan)點(dian)(dian)較閉口杯(bei)高。一般相差10~30℃，油品越(yue)重(zhong)，閃(shan)(shan)點(dian)(dian)越(yue)高，差別(bie)也(ye)越(yue)大(da)。重(zhong)質(zhi)油品中(zhong)加入少量低(di)沸點(dian)(dian)油品，會(hui)使閃(shan)(shan)點(dian)(dian)大(da)為降(jiang)低(di)，而且(qie)兩種(zhong)閃(shan)(shan)點(dian)(dian)的(de)(de)差值也(ye)明顯增大(da)。由(you)于(yu)石油產品閃(shan)(shan)點(dian)(dian)的(de)(de)測(ce)定時條件試(shi)(shi)驗(yan),所用儀(yi)器規定及操作方法(fa)必(bi)須按(an)國(guo)家標準進(jin)行。