Issue 161-M

البحـث الثاني

139

2016

أوابك العلمية لعام

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ص لبحوث العلمية الفائزة بجائزة

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عدد خا

مجلة النفط والتعاون العربي

161

العدد

- 2017

أربعون

المجلد الثالث و ال

Re-refining of Used Lubricating Oil and its Economic and Environmental Implications

- Additives present in the lubricant will oxidize and form corrosive acids at elevated

temperatures.

3.3 Characteristics of used lubricating oil versus virgin and re-refined oils

Abro et Al (2013) carried out an experimental work to determine the effect of re-refining

on the properties of used lubricating oil. The re-refined oil’s properties such as, specific

gravity, ash content, viscosity, flash point, and metal content were analyzed and

compared to those of virgin oil. The findings are presented in Figure 6 and Figure 7.

Figure 6 shows that the specific gravity of re-refined oil (0.88) is sensibly equal to virgin

oil (0.9) and lower than the used oil (0.93). The ash content of the re-refined used

lubricating oil was significantly reduced from 2.02% to 0.09%.

As illustrated in Figure 7, viscosity, which is an important parameter for consideration

when it comes to choosing lubricating oils, has been decreased from 120 cP(used lube

oil) to 94 cP(re-refined lube oil). The flash point of the re-refined oil was significantly

improved from 120ºC (used oil) to 150ºC (re-refined oil) while iron content was reduced

from 50 ppm to 13 ppm.

From these results it can be stated that re-refining effectively removed impurities from

contaminated used oil. It can also be said that the quality of re-refined used lubricating

oil is comparable to virgin lubricating oil.

3.4

Types of used lubricating oil suitable for re-refining

Generally speaking, only used lube oils with high viscosity index and less contaminant

are suitable for re-refining (Fiedler, 2005). Based on the European waste category, the

European re-refining industry association (GEIR) considers the following used

lubricating oils suitable for re-refining:

- Engine oils without chlorine

- Hydraulic oils without chlorine

- Non-chlorinated mineral oils