碱性氮化物对润滑油催化降凝的影响

EFFECT OF BASIC NITROGEN COMPOUNDS (BNC) ON CATALYTIC DEWAXING OF LUBE OIL FRACTIONS

本文比较了润滑油馏分脱除碱性氮化物前后的催化降凝效果(采用择形分子筛崔化剂)。考察了碱性氮化物——吡啶、2,4-二甲基喹啉(DMQ)对已脱除碱性氮化物的润滑油馏分催化降凝的影响。结果表明:吡啶可使催化剂的降凝活性完全丧失,因而认为吡啶分子可进入分子筛孔道内部;DMQ对轻质润滑油馏分(其中的蜡主要由直链烷烃组成)降凝效果的影响不明显,因而认为它只能使催化剂外表面的活性中心失活,而不能进入分子筛孔道内部:润滑油馏分中的碱性氮化物对催化降凝效果的影响近似于DMQ。

The catalytic dewaxing (CDW) of lube oil fractions with shape selective zeolite catalyst before and after the removal of basic nitrogen was compared. The effect of pyridine and 2, 4-dimethylquinoline (DMQ) as BNC on catalytic dewaxing of BNC free lube oil fractions was also investigated. It ha s been found that:(1) The dewaxing activity of the zeolite catalyst is completely inhibited by the presence of pyridine, suggesting that the pyridine molecules are able to enter readily into the channels of the zeolite.(2) The effect of 2,4-dimethylquinoline (DMQ)on CDW of light lube oil fractions with waxes mainly composed of straight chain paraffins is not significant, suggesting that DMQ can not enter the interior of the zeolie's channels.Therefore, only the active sites on the external surface of the zeolite catalyst are poisoned by DMQ.(3) The BNC originally contained in the lube oil fractions has a similar effect as DMQ.