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160
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
37
4.13.2
Process features and drawbacks
The process is claimed to enable energy and capital cost savings over other solvent
extraction processes. This technology permits the treatment of used engine oils mixed
with lubricating grease, provided that the content of the latter does not exceed 5%.
Grease is made up of 85% of oil. This technology enables important energy savings to
be made, due to the recovery of the solvent in supercritical conditions. As with Interline
technology, it also allows the oil content in grease to be recovered.
4.14 Acid/Clay (Meinken) process
Although this technology is phasing out, it is described briefly below and is carried out
as follows:
4.14.1
Process description
The process consists of the following steps:
Pretreatment:
The waste oil is filtered to remove any solid impurities. The oil is dewatered in large
settling tanks wherein the heavier water settles to the bottom of the tank and the lighter
oil floats on top. The water at the bottom is drained off and should normally be treated
before disposal. However, this does not remove the water completely and a small
quantity still remains.
Figure 21 shows the flowchart of the process.
4.14.2
Process features and drawbacks
For economic reasons and because of environmental pollution inherent to the treatment
of acid clay/earth, the technology is no longer in use. The process involves problems of
internal corrosion and disposal. The main advantages of this process are the low
investment and maintenance costs, the possibility of treating low quality used oil and
ease of handling the process itself. The process cannot remove sulphur compounds,
polycyclic aromatic hydrocarbons. Final product quality is related to the quality of raw
material. There exists modified Meinken process that includes the use of thin film and
contact distillation techniques.