Research Journal of Environmental and Earth Sciences 4(10): 912-916, 2012
ISSN: 2041-0492
© Maxwell Scientific Organization, 2012
Submitted: September 15, 2012
Accepted: October 15, 2012
Published: October 20, 2012
Recycling of Automotive Lubricating Waste Oil and Its Quality Assessment for
Environment-Friendly Use
1
Naveed Anwar, 1Syed Shahid Ali, 2Zubair Anwar, 2Jabar Zaman Khan Khattak, 3Abdul Jabbar,
3
Tariq M. Ansari and 4Syed Sibtain Raza Naqvi
1
Department of Environmental Sciences,
2
Department of Biotechnology and Bioinformatics, International Islamic University, Islamabad, Pakistan
3
Department of Chemistry, G.C. University, Faisalabad, Pakistan
4
HDIP Petroleum Testing Centre, Multan, Pakistan
Abstract: Lubricating oils, which are formulated with a number of chemicals blended base oils provide products
that last longer, keep machinery cleaner and allow the machinery to work better under severe operating conditions.
However, the used oil-waste generated by the automobiles and other allied industries poses an environmental
hazard. The motivation of the present research study was to study the merits and demerits of commonly applicable
technique acid/clay for reclamation of waste oil. This process has been employed for many years as the premier type
of re-refining in which concentrated sulfuric acid is introduced to dehydrate waste lubricating oil. An acidic sludge
is produced which is treated with clay. In this study, the conventional process of reclamation of waste oil, which is
acid/clay, has been reviewed in the light of recovered product quality and hazardous effects on the environment and
human health. Forty samples, in which, waste oil (10), reclaimed oil (30) were collected from different blending and
reclamation plants located in different areas of the Punjab Province and were compared with two stroke blended oil
(10 samples). The samples were tested for kinematic viscosity at 40 and 100ºC, Viscosity Index, Flash point,
Sulfated Ash content, Copper Corrosion, Water content, Sediments and Color by following the standard ASTM
Methods D-445, D-2270, D-92, D-482, D-130, D-95, D-473 and D-1500 (ASTM, 2002), respectively. According to
the results, blended reclaimed (two stroke) oil samples were found up to the recommended standard test limits. On
the other hand, waste oil and reclaimed oil samples were found above the maximum test limits of acid number and
copper corrosion and were found below in flash point test limit. Waste oil samples were highly contaminated and
adulterated with mud and water. Although no such standard criteria or parameters are available for comparison but
analysis results showed a bad reflection and due to which only few tests like copper strip corrosion, water content,
sediments and flash point were performed to understand the characteristics of the market available waste oil product.
These results showed that product is not environment friendly and the processing method needs to be improved.
More research is needed to find out atmospheric pollution due to burning or use of reclaimed and waste oil on
human health especially from occupation health and safety perspective.
Keywords: Environmental pollution, health hazard, occupational safety, reclaimed oil, waste oil
different viscosity-based oils with suitable proportion of
additives. Base oils are either derived from crude oil or
are synthetic material manufactured by chemical
processes (Jha, 2005).
Lubricants possess a combination of intrinsic
properties, such as viscosity, volatilities, thermal and
oxidative stability, load carrying ability, solubility and
other physical, mechanical and chemical properties; and
additive properties which are imparted to the lubricants
by the incorporation of special additives such as rust
preventives, corrosion inhibitors, detergents and
dispersants, extreme pressure agents, oxidation
inhibitors and most of other additives. The selection of
a lubricant is not solely based upon its stability to
INTRODUCTION
Lubricating oils from petroleum consists of
complex mixtures of hydrocarbon molecules, mostly
composed of isoalkanes having slightly longer branches
and the monocycloalkanes and monoaromatics having
several short branches on the ring (Cotton, 1982).
Lubricating oils are fluids such as engine oils, gear,
hydraulic oils, turbine oils, etc., used to reduce friction
between moving surfaces. They also serve to remove
heat from working parts in machinery, remove wear
debris, created by moving surfaces and provide a
protective layer on the metal surfaces to avoid
corrosion. Lubricating oils are prepared by blending
Corresponding Author: Syed Shahid Ali, Department of Environmental Sciences, International Islamic University, Islamabad,
Pakistan
912
Res. J. Environ. Earth Sci., 4(10): 912-916, 2012
reduce wear and friction but on possessing an optimum
combination of intrinsic and additive properties which
best meet the overall requirements, important in the
application (Kinghorn, 1983).
It
became
serious
concerns
for
to
environmentalists, governments, industries and research
scientists how to handle and what to do with the used
lubricating oils. These wastes are difficult and costly to
dispose of in an environmentally acceptable manner.
The common disposal technique of used lubricating oils
is burning for generation of energy. Burning and all
other routes of disposal of used lubricating oils are
uneconomical and result in wastage of resources.
Extensive research study is underway worldwide on
degradation of fuels, lubricants, their analysis and
recycling. The recycling of waste lubricating oils may
be a suitable and economical alternative to burning and
incineration. Used lubricating oil disposal techniques of
the past such as land filling, road oiling, indiscriminate
dumping, burning for energy generation etc., have
created serious environmental hazards. Many of these
disposal techniques were severely restricted by current
state and federal environmental regulations (Pyziak and
Brinkman, 1993). Hence, recycling of waste lubricating
oils can be an appropriate and economical substitute to
burning and incineration (Bhaskar et al., 2004). The
classical acid-clay treatment process uses concentrated
sulfuric acid to eliminate asphaltenic compounds,
yielding highly poisonous acid materials. In the
reclamation process using acid-free clays, waste oils are
initially treated with natural polymers to remove
carbonic materials and, afterward, are subjected to
vacuum distillation and clay treatment in the
appropriate amount to obtain the right end product
coloration. Besides the high costs due to the required
quantity of clay, reclaimed oils obtained by this method
still have relatively high metal percentages (Hamad
et al., 2005).
In Pakistan, there are 5 million vehicles are on the
roads and require lubricating oil change every other
month or after a certain mileage, however, disposal of
waste or its reuse has not been evaluated (Shakirullah
et al., 2006). The objectives of current research study
were: to study the merits and demerits of commonly
applicable technique i.e., acid/clay for reclamation of
waste oil & to evaluate the waste oil for its physical and
chemical properties viz-a-viz, its persistence, possible
recycling or re-use.
MATERIALS AND METHODS
Material: Fifty samples, in which, 10 waste oil, 30
reclaimed oil and 10 samples of 2-stroke oil were
collected from different blending and reclamation
Table 1: Samples of lubricating oils and their source (manufacturers)
Sample no
Sample code
1
Waste oil (manufacturer-A)
2
Waste oil (manufacturer-B)
3
Waste oil (manufacturer-C)
4
Reclaimed oil (manufacturer-A)
5
Reclaimed oil (manufacturer-B)
6
Reclaimed oil (manufacturer-C)
7
Blended oil (manufacturer-A)
8
Blended oil (manufacturer-B
9
Blended oil (manufacturer-C)
Table 2: Typical analysis specifications of waste lube oil (Pakistan
Standard Institution, 1990; Ministry of Petroleum & Natural
Resources, Government of Pakistan, No. PL-L (870)/99
(Spec))
Standard test
Test description
method
Range
Water contents (% in
ASTM D-95
5 to 10%
emulsion w/w)
Flash point (ºC)
ASTM D-92
100 to 190ºC
Viscosity at 40ºC (cSt)
ASTM D-445
70 to 110
Sulphated Ash (% w/w)
ASTM D-482
1.5 to 3.0%
Total acid no. (mg KOH/gm) ASTM D-664
1
Pentane insoluble (% w/w)
ASTM D-893
1%
Specific gravity
ASTM D-1298 0.850 to 0.900
Table 3: Pakistani standard test limits for lubricating oils (Pakistan Standard
Institution, 1990; Ministry of Petroleum & Natural Resources,
Government of Pakistan, No. PL-L (870)/99 (Spec))
Test description
Grade-I
Grade-II
Grade-III
Test method
ASTM color
3.5
6.5
8.0
ASTM D-1500
(Max.)
Flash point °C
218
218
204
ASTM D-92
(Min.)
Viscosity index
95
75
65
ASTM D-2270
(Min.)
Pour point °C
10
15
20
ASTM D-97
(Max.)
Copper strip Corr.
1
1
1
ASTM D-130
Ash wt % (Max.)
0.05
0.05
0.1
ASTM D-462
Conradson Carbon
nr
nr
nr
ASTM D-189
wt %
Specific gravity at
nr
nr
nr
ASTM D-1298
60/60°F
Total acid No. (mg
0.05
0.05
0.05
ASTM D-664
of KOH/gm)
Pentane insoluble
0.01
0.05
0.10
ASTM D-893
(Max.)
Sponification No.
0.2
0.2
0.5
ASTM D-94
(Max.)
plants located in different areas of Punjab Province. A
list of samples is given in the Table 1.
Chemicals and equipments: Analytical Grade
Reagents supplied by Merck were used throughout this
study. Measurements were made using Viscometer
Bath (VHC-220-DIOV, GALLENKAMP and England),
Viscometer (POULTEN SELF and LEE, LTD.
WICKFORD, England), Copper Corrosion Tester
(KOEHLER, USA) and Cleveland Open Cup (C.O.C)
Flash Point Tester (Semi-Automotive Cleveland DIN51376, LAUDA and Germany). DEAN AND STARK
Apparatus (KOEHLER, USA), Sediments Unit (SETA,
913 Res. J. Environ. Earth Sci., 4(10): 912-916, 2012
Table 4: Guidelines for international quality standards of re-refined base oil
(Pakistan Standard Institution, 1990)
Grade
--------------------------------------------------------------Test description
(Max.)
150
G-1
G-2
G-3
500
Viscosity at 100ºC
5.0±0.2
11.0±0.4
(cSt)
Viscosity index
90-110
95
75
65
90-110
Flash point PMC (ºC)
210
218
218
204
230
Pour point (ºC)
-9
10
15
20
-9
ASTM color (Max.)
3
3.5
6.5
8.0
4.5
Copper corrosion
1
1
1
1
1
Chlorine (ppm) Max.
10
10
Water (ppm) Max.
50
50
PAHs (%) Max. “IP3
3
246”
PAHs (ppm) Max.
250
250
Individual metals
10
10
(ppm) Max.
Sulphated ash (%)
0.01
0.05
0.05
0.1
0. 01
Max.
Noack volatility (%
18.0
6.0
loss) Max.
Ring analysis CA
0.1
0. 1
(%) Max.
Dialysis residue (%)
0.1
0. 1
Max.
Total acid number
0.01
0.05
0.05
0.10
0.01
(TAN) mg (KOH/g)
Max.
Table 5: Pakistani standard test limits for two stroke oils (Ministry of
Petroleum & Natural Resources, Government of Pakistan,
No. PL-L (870)/99 (Spec))
Two stroke oil
--------------I
II
Test description
Test method
Flash point ºC (Min.)
177
140
ASTM D-92
Kinematic viscosity @ 100ºC
9.0
8.5
cSt (Min.) (Max.)
12.5
12.5
ASTM D-445
Viscosity index (Min.)
85
85
ASTM D-2270
Sulfated Ash wt % (Min.)
ASTM D-874
Copper strip corrosion 3 h. @
1
1
ASTM D-130
100ºC (Max.)
Pour point ºC (Max.)
ASTM D-97
England), Muffle Furnace (FSE-621 Series,
GALLENKAMP, England), Electrical Balance (S2000, BUSCH COMPANY, England) Color meter
(SETA, England), Potentiometer (960-Autochemistry,
ORION, Japan) etc.
Methods
Physical parameters: Physical properties of oil, i.e.,
kinematic viscosity at 40 and 100°C, Viscosity Index,
Flash point, Sulfated Ash content, Copper Corrosion,
Water content, Sediments and ASTM Color, were
determined by following ASTM Standard Methods D445, D-2270, D-92, D-482, D-130, D-95, D-473, D1500, respectively (ASTM standards, 1999),
respectively (Table 2 to 4). Pakistani standard test
limits for two stroke oils are given in Table 5.
RESULTS AND DISCUSSION
Physical parameters: Results have been presented in
for waste oils (Table 6), reclaimed oils and blended oils
(Table 7). The results were compared with Pakistan
Standard (Pakistan Standard Institution, 1990) and the
International Standards (Table 2 to 5), respectively.
Three samples of reclaimed oil each with three
replications were compared with standard individual
physical parameters. Results have been presented in for
waste oils (Table 6), reclaimed oils and blended oils
(Table 7).
Kinematic viscosity: The Kinematic Viscosity at 100
and 40ºC parameter in Pakistan Standard (PSI) for all
three grades of reclaimed oil was not available, where
as International Standard were categorized reclaimed
oil into two grades and assigned number 150 and 500
(Table 4). For these grades the minimum kinematic
viscosity is reported 5.0 and 11.0 cSt respectively.
When compared the samples analysis results in respect
of kinematic viscosity at 100oC with international
standard, two samples met the minimum limit in grade
500 that is 11.0 (minimum) of reclaimed oil. Kinematic
viscosity at 40°C was not reported in the literature and
neither in the standard tests limits, this is because
mostly in oil industry, lubricating base oil grades are
based on viscosity index parameter (Table 7).
Viscosity index: Viscosity Index is used in practice as
a single number indicating temperature dependence of
kinematic viscosity. This parameter in PSI for
reclaimed oil is limited for G-1, G-2 and G-3 in the
minimum range of 95, 75 and 65 respectively. Whereas
International standard limits are 90 to 110 for both
grades. This behavior purport that all samples of
reclaimed oil met the PSI limit of grade-1 and grade-2.
One sample showed above 100 while other two showed
index of 89.
Flash point: None of the reclaimed oil sample met the
minimum requirement of flash point in both categories
of PSI as well as international standard limit. PSI
restricted the minimum requirement 218°C for G-1, G-
Table 6: Physical parameters of waste oil samples determined by ASTM procedures
Water contents dean and
Sediments (Wt %)
Sample No.
stark (mL %) ASTM D-95
ASTM D-473
1.
3.4
1.28
2.
3.9
1.29
3.
6.8
5.18
914 Flash points (COC) (°C)
ASTM D-92
216
207
225
Copper strip corrosion at
100°C for 3 h ASTM D-130
4a
3b
3b
Res. J. Environ. Earth Sci., 4(10): 912-916, 2012
Table 7: Physical parameters of reclaimed & blended oil determined by ASTM procedures
Kinemat.
Kinemat.
viscosity
Viscosity @
Viscosity
Flash point
ASTM
Sample Code
@100°C (cSt)
40°C (cSt)
index
(COC) (°C) color
Rec. oil
11.92
117.25
89
180
L 4.5
(Man-A)
Rec. oil
11.75
114.48
89
162
L 4.5
(Man-B)
Rec. oil
10.52
85.770
106
189
L 3.0
(Man-C)
Blnd oil
11.27
78.950
133
240
L 2.5
(Man-A)
Blnd oil
11.00
93.120
103
222
L 3.5
(Man-B)
Blnd oil
10.88
81.740
119
222
L 2.0
(Man-C)
2 and 204°C for G-3, whereas 210 and 230°C for 150
and 500 grade in international standard. This trend
the vacuum was increased from 12 to 26 kPa (kilo
Pascal) /mmHg (millimeters of mercury) in deodorizer,
where the maximum lighter ends were extracted. Due to
this, the quality of the finished reclaimed oil would
increase but quantity of the product decrease. To avoid
this product quantity decrease, the blender knowing
avoid this technique (Table 7).
Neutralization number is a measure of the acidity
or alkalinity of oil. The number is mass in milligrams of
the amount of acid (HCl) or base (KOH) required
neutralizing one gram of oil. PSI restricted the
maximum limit of 0.05 mg for G-1, G-2 and 0.1 mg
(KOH)/g for G-3 grade and the international standard
restricted 0.01 mg (KOH)/g for both grades; 150 & 500.
Two analyzed reclaimed oil samples were above the
minimum range of 0.05 and one met the international
standard limit 0.01. Statistically we can say that
samples are not environment friendly products as they
are exceeding the maximum limit 0.05 (Table 7).
Copper strip corrosion test method: Copper
Corrosion test method covers the detection of the
corrosiveness of copper of aviation gasoline, aviation
turbine fuel, automotive gasoline, natural gasoline or
other hydrocarbons having a Reid vapor pressure no
longer than 18 psi (124 kPa), cleaners (Stoddard)
solvent, kerosene, diesel fuel, distillate fuel oil,
lubricating oil and certain other petroleum products. In
the case of reclaimed oil samples, two samples were in
the range of slight tarnish and fall in category of 1b and
one sample was up to standard limit and met the
category of 1a. It is noted that the samples having
viscosity index above than 100 met the standard test
limit and the sample having viscosity index below 90
were in the category of slight tarnish (Table 7).
Therefore, slight tarnish category is harmful if the
product is used without any blending with virgin base
oil. Here it is a common practice that the blender can
sell the reclaimed oil in the market without blending or
any treatment to neutralize the acidity.
Ash Cont.
(Wt %)
0.036
Copper strip
corrosion @
100oC
1b
Acid No.
(mg KOH/g)
0.09
0.046
1b
0.08
0.027
1a
0.01
0.005
1a
-
0.006
1a
-
0.004
1a
-
showed lack competency or slackness. In the study it
was observed that the flash point could be increased if
Ash contents: Ash Contents denote the metallic
deposits formed in the combustion chamber and other
parts of the engine during high temperature operation.
The ash content of oil, determined by charring the oil,
treating the residue with sulfuric acid, an evaporating to
dryness and expressed as percentage by mass. All
reclaimed oil samples met the standard test limit, which
is 0.05 according to PSI but none of the sample met the
standard test limit of 0.01 (maximum) ranges according
to International Standards (Table 7).
Similarly three blended reclaimed oil samples with
a repetition of three were analyzed following the same
test techniques and procedure for each physical
parameter (Table 7). Two-Stroke Oil category, in
developed countries is superseded fifty years back
because of ash content and carbon residue and
development in the engine design and performances.
However, in Asia and particularly in third world, this
product is used for slow machineries and other two
stroke engines. In Pakistan three grades, Ordinary Oil,
Two Stroke Oil-1 and Two Stroke Oil-2 are available
and recognized by the Ministry of Petroleum and
Natural Resources and approved the standard test limits
(Table 5). Three samples of two stroke blended
lubricating oil each with three repetitions, which were
collected from blending and reclamation plants were
analyzed (Table 7).
These samples were especially blended with the
virgin base oil and reclaimed oil, which were already
collected and tested during this research study. The
analysis results were then compared with the available
approved standard test limits of two stroke lubricating
oil as well as with the tested reclaimed oil for
comparison purposes. None of the sample met the
standard test limit of ordinary oil in major physical
parameters like viscosity and sulphated ash content. All
samples met the two stroke grade-1 category, with
slight higher viscosity and flash point with improved in
915 Res. J. Environ. Earth Sci., 4(10): 912-916, 2012
ASTM color and ash content but did not meet the
ordinary oil grade.
It was, further noted that due to the blending with
virgin base oil; all physical characteristics were
improved and stabilized formation. When compared
with the analyzed reclaimed oil characteristics. It is
very interesting to point out that blended two stroke oil
showed improvements in different important physical
parameters. ASTM Color was stabilized and
consistency in the range of 2.0 to 3.5, which is
acceptable in the market. Similarly ash content
decreases and remains in the acceptable and
environmental friendly range of 0.001 to 0.005% Wt.
Copper Corrosion was also stable and remains within
the range of standard test limit, which is 1a. This
parameter is very important especially for engine wear
and tear.
Overall quality of marketed product: Three waste oil
samples with three replications were analyzed to
understand the quality of the available market product
(Table 4). Water and sediments in all samples were on
higher side. Flash point is above 200°C and maximum
225°C. This higher flash point is initially due to
contaminants and second samples were tested after
water dryness means evaporation initially at 100°C.
This is because to protect the instrument sensitivity and
damage. Both water and sediments in the waste oil were
on higher side and a risk to tests these types of samples
before some treatment such as removal of water and
sediments. After that treatment the analysis results may
not be authentic. However, the samples were tested and
presented the results for general understanding
regarding the quality of the product. It is also necessary
to mention here that all the samples of waste oil were
heavily contaminated, which was confirmed by
following the test of copper strip corrosion test. All
samples were fall in a category of dark and high
corrosive limit. These types of waste oils, on one hand,
are very dangerous for the environment, because when
treated with sulfuric acid needed high dosage of acid
and second recovery of reclaimed oil will also decrease
(Preston and Trocki, 2000; Whisman et al., 1974).
However, the acidic sludge and oil clay disposal is a
matter of greater environmental concern.
CONCLUSION
Lubricating oils, which are formulated with a
number of chemicals named “Additives” blended with
base oils (virgin oil) to provide required products that
last longer keep machinery cleaner and allow the
machinery to work better under severe operating
conditions. Acidic material is then neutralized with
hydrated sodium silicate (fuller earth).
According to this study, Waste oil samples were
found highly contaminated and adulterated with mud
and water. Although no such standard criteria or
parameters are available for comparison but analysis
results showed a bad reflection and due to which only
few tests like copper strip corrosion, water content,
sediments and flash point were performed to understand
the characteristics of the market available waste oil
product. The reclaimed oil samples were at maximum
test limits in acid number and copper corrosion and
below in flash point test limit. This trend showed that
recovered product is not environment friendly and need
to improve the processes technique.
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