dc.description.abstract |
Automotive lubricating oils play a most vital role in our great complex civilization.
To estimate the importance of its role one need only consider that every moving part
of every machine is subjected to friction and wear. Friction consumes energy; wear
causes changes in dimensions and eventual breakdown of the machine. To overcome
this problem, lubricating oil is used to reduce friction, protect against wear, carry
away heat, protect against rust and remove contaminants from the engine. This
lubricating oil is made from crude oil after refining by introducing proper additives
and its sources and reserves are limited and are not inexhaustible throughout the
world.
The used oil loses its effectiveness during operation due to the presence of
contaminants. This oil is less subject to biodegradation and does not
evaporate but
becomes contaminated with substances that are hazardous to human health and the
nvironment, so before it can discharged to the environment this oil requires suitable
collection and treatment. Therefore to avoid adverse impacts, proper management of
waste oil is needed.
In this study, waste oil disposal practice in Pakistan has been identified as has the
adverse environmental impact associated with it and waste oil management options
are discussed in relation to proposed re-cycling options considering the prevailing
market price of the new virgin oil. 12 re-generation locations have been identified all
over Pakistan to create job opportunities for local people and also reduce transport
costs.
This study was carried out to evaluate the performance of different methods used to
upgrade the waste lube oil into a usable product. Acid/ clay treatment was conducted
at laboratory and small pilot scale using the sulfuric acid with different catalysts
(Dimethyl Sulfoxide, Dimethyl Formamide and Zeolite) and waste oil ratios. The
performance was evaluated against the properties of regenerated oil to the standard
base oil, 500N and 150N, and it was found that regenerated oil does not match to
standard base oil.
In the solvent-extraction process, the performance was evaluated using single and
composite solvents with catalysts at laboratory and pilot scale level. The two
dependent variables, namely the Percentage of oil loss (POL) and Percentage of
Sludge Removal (PSR) were examined as the key parameters in assessing the
performance of the extraction process. The solvents used were (70% of 2-propanol
and 30% of n-hexane) with addition of KOH, composite solvents (40% 2-propanol,
35% 1-butanol and 25% butanone) and (25% 2-propanol, 37% 1-butanol and 38%
butanone) at different solvent-oil ratio and operating variables.
In view of the practically and commercial aspect of the project, the used oil recycling
process was consecutively run for three or four times at each composition. The
physical properties of recovered/re-generated base oil were analyzed and compared.
The results from the experimental work shows the laboratory and pilot scale operation
revealed similar trends with a little higher performance from the pilot scale operation.
This is due to the mechanical mixing of acid-oil/ solvent-oil, coagulants, activated
earth clay and controlled heating (dehydration & distillation) extraction of light
hydrocarbons and solvents.
The properties of re-generated oil were matched to the standard base oil, 500N and
150N, the properties of solvent–oil ratio (25% 2-propanol, 37% Butanol and 38%
Butanone) at SOR 6:1 was observed to be the most appropriate solvent composition
and achieved about 68% oil recovery and the oil properties compared favorably to
graded virgin oil and can be used for similar purposes. Since the quality of
regenerated oil matched the virgin oil, it would reduce our dependency on imported
oil, save foreign exchange, reduce adverse environment impact and help to preserve
oil sources. |
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