油品的閃點(dian)、燃點(dian)與(yu)自燃點(dian)與(yu)油品的組成關系:

1.與化學組成有(you)關(guan):通常情況下，烷(wan)(wan)烴(jing)(jing)(jing)(jing)(jing)(jing)比(bi)芳(fang)烴(jing)(jing)(jing)(jing)(jing)(jing)容易氧化，故含烷(wan)(wan)烴(jing)(jing)(jing)(jing)(jing)(jing)多的(de)油品(pin)自燃點比(bi)較(jiao)低，但其閃(shan)點卻比(bi)粘(zhan)度相(xiang)同(tong)而(er)(er)含環烷(wan)(wan)烴(jing)(jing)(jing)(jing)(jing)(jing)和芳(fang)烴(jing)(jing)(jing)(jing)(jing)(jing)較(jiao)多的(de)油品(pin)高。在同(tong)類烴(jing)(jing)(jing)(jing)(jing)(jing)中，隨相(xiang)對(dui)分子(zi)質量增(zeng)大，自燃點降低，而(er)(er)閃(shan)點和燃點增(zeng)高。對(dui)碳原子(zi)數相(xiang)同(tong)的(de)烴(jing)(jing)(jing)(jing)(jing)(jing)類，自燃點的(de)順序為烷(wan)(wan)烴(jing)(jing)(jing)(jing)(jing)(jing)<環烷(wan)(wan)烴(jing)(jing)(jing)(jing)(jing)(jing)，烯(xi)烴(jing)(jing)(jing)(jing)(jing)(jing)<芳(fang)烴(jing)(jing)(jing)(jing)(jing)(jing);嫩(nen)點的(de)順序正(zheng)好相(xiang)反:烷(wan)(wan)烴(jing)(jing)(jing)(jing)(jing)(jing)>環烷(wan)(wan)烴(jing)(jing)(jing)(jing)(jing)(jing)，烯(xi)烴(jing)(jing)(jing)(jing)(jing)(jing)>芳(fang)烴(jing)(jing)(jing)(jing)(jing)(jing)。

2.與餾(liu)(liu)分組成(cheng)有關:油品的(de)閃點與其(qi)蒸氣壓有關，亦與其(qi)餾(liu)(liu)分組成(cheng)有關，油品的(de)沸(fei)點越(yue)(yue)(yue)(yue)高(gao)、餾(liu)(liu)分越(yue)(yue)(yue)(yue)重、相(xiang)對分子質(zhi)(zhi)量越(yue)(yue)(yue)(yue)大，其(qi)閃點越(yue)(yue)(yue)(yue)高(gao)。反之,油品的(de)沸(fei)點越(yue)(yue)(yue)(yue)低(di)，餾(liu)(liu)分越(yue)(yue)(yue)(yue)輕，相(xiang)對分子質(zhi)(zhi)量越(yue)(yue)(yue)(yue)小(xiao)，越(yue)(yue)(yue)(yue)易揮(hui)發,其(qi)閃點和(he)燃點越(yue)(yue)(yue)(yue)低(di)。油品閃點和(he)燃

點(dian)(dian)(dian)的(de)(de)高(gao)低取決(jue)于(yu)(yu)低沸點(dian)(dian)(dian)烴(jing)類含量(liang)，烷烴(jing)的(de)(de)閃點(dian)(dian)(dian)比(bi)對應的(de)(de)烯烴(jing)要(yao)高(gao)。油(you)(you)(you)(you)(you)(you)品(pin)閃點(dian)(dian)(dian)的(de)(de)高(gao)低取決(jue)于(yu)(yu)油(you)(you)(you)(you)(you)(you)品(pin)中(zhong)沸點(dian)(dian)(dian)zui低的(de)(de)那(nei)部分烴(jing)類的(de)(de)含量(liang)。當有極少(shao)量(liang)輕(qing)油(you)(you)(you)(you)(you)(you)混人到(dao)高(gao)沸點(dian)(dian)(dian)油(you)(you)(you)(you)(you)(you)品(pin)中(zhong)時(shi)，就能引(yin)起(qi)閃點(dian)(dian)(dian)顯著降低。例如，某潤滑油(you)(you)(you)(you)(you)(you)中(zhong)摻人1%的(de)(de)汽(qi)油(you)(you)(you)(you)(you)(you)，閃點(dian)(dian)(dian)可從200°C降至170°C。正是由于(yu)(yu)這一原因，原油(you)(you)(you)(you)(you)(you)的(de)(de)閃點(dian)(dian)(dian)是很低的(de)(de)，它和低閃點(dian)(dian)(dian)油(you)(you)(you)(you)(you)(you)品(pin)一起(qi)被列人易(yi)燃(ran)物(wu)品(pin)之(zhi)中(zhong)。與燃(ran)點(dian)(dian)(dian)相反，油(you)(you)(you)(you)(you)(you)品(pin)的(de)(de)沸點(dian)(dian)(dian)越(yue)低，越(yue)不易(yi)自(zi)燃(ran)，其(qi)自(zi)燃(ran)點(dian)(dian)(dian)就越(yue)高(gao);反之(zhi)，自(zi)燃(ran)點(dian)(dian)(dian)越(yue)低。對同-烴(jing)類沸點(dian)(dian)(dian)越(yue)高(gao)其(qi)燃(ran)點(dian)(dian)(dian)越(yue)高(gao)沸點(dian)(dian)(dian)越(yue)高(gao)其(qi)自(zi)燃(ran)點(dian)(dian)(dian)反而較低。