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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
21
4.2.1
Process features and drawbacks
The vacuum residue of this process may represent a major environmental problem if
not valorized in a commercial operation such as asphalt manufacture (can be used as
asphalt extender). Key to the process is the thin-film vacuum distillation. The yield of
finished base oil is about 82%.(UNEP, 2014, Walker R, 2013). The first re-refining plant
(20000 MTPY) to utilize the KTI Process was completed in 1982 (Fok, 1986).
4.3
The CEP/Mohawk process
The CEP process-also known as CEP-Mohawk process- was introduced in the late 1980s
by Chemical Engineering Partners (CEP).
4.3.1
Process description
The process consists of the following steps:
Feedstock analysis:
Due to process consideration the feedstock must analyzed to make sure it is suitable for
re-refining.
Chemical treatment:
In order to reduce fouling in the process equipment, the feedstock undergoes a chemical
treatment whereby water and light hydrocarbons are removed. Next the contaminants
and additives are removed to avoid catalyst poisoning.
Vacuum distillation:
After pre-treatment, the feedstock is sent to a wiped film evaporator operating under
vacuum. The vacuum allows the separation of base oil from additives below cracking
temperatures.
Hydrotreatment:
Three hydrotreating reactors are used in series to reduce sulfur and increase saturates to
produce base oils meeting specifications for API group II.
Fractionation:
The hydrotreated base oil is separated into light and heavy cut.
4.3.2
Process features and drawbacks
The hydrotreating process is claimed to reduce sulfur to less than 300 ppm and increase
saturates to over 90%, meeting the key specifications for API Group II base oil.