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170
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
47
5.2.3 Acid/Clay processes
As discussed earlier, an acid (generally sulfuric acid) is used to extract oxygen
compounds, asphalt, resin derivatives, other nitrogen and sulphur-based compounds
and metal contaminants from the used oil. The active clay removes the color and odor.
The acid/clay based processes are obsolete and are no longer in use. Some existing
plants have been converted to operate under new technologies such as RTI.
5.3
Which technology to use?
There is no single “right technology” for re-refining. Each technology has both merits
and shortcomings. The method employed to re-refine waste oil depends on many
factors such as the nature of the base stock, the nature and amount of contaminants, and
many other economic factors. Suffice to say that today modern technologies seem to be
converging towards a two-step procedure: vacuum distillation of dehydrated used
lubricating oil and subsequent hydrotreatment of distilled stocks.
Among these technologies, we can list: Mohawk, Safety Kleen and Revivoil.
Table 3 summarizes the advantages and disadvantages of the various re-refining
methods.