TOPIC:
USED WASTE OIL
BY
ZAINAB LABARAN
QUEENALINE ANOH MBANWI
21802895
21906414
INTRODUCTION
Oil keeps our cars, lawnmowers, and many other machines running smoothly. Used oil is any petroleumbased or synthetic oil that has become unsuitable for the use to which it was initially assigned. These
especially include used oils from combustion engines, transmission systems, turbines and hydraulic
systems, the different sectors of the car industry and industrial shipping activities. During normal use,
impurities such as dirt, metal scrapings, water, or chemicals, can get mixed in with the oil, so in time, the
oil no longer performs well. Eventually, this used oil must be replaced with virgin or re-refined oil to do
the job correctly (EPA, 2019 and RAC/CP, 2000).
Lubricating oil wastes are dumped on the ground, under a ditch, or sent to a landfill, which is eventually
absorbed into the ground or floats on the water surface (Mohammed, 2013). It is estimated that more than
30.3 billion liters of used oil are produced every year. This lubricant waste has a very high hazardous
content from ash, carbon residue, asphaltenes, materials, metals, water, and other dirty materials produced
during lubricants inside the machine. Used oils as hazardous wastes if disposed directly into the
environment, especially rivers, seas and lakes create problems, such as the problem of disposing of used oil
into water bodies not only contaminate water but also harmful to freshwater and marine life (Udonne, 2013).
The benefits of reusing and recycling used oil
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Recycling and reusing used motor oil is preferable to disposal and can provide great environmental
benefits by keeping it from polluting soil and water.
Recycled used motor oil can be re-refined into new oil, processed into fuel oils, and used as raw
materials for the petroleum industry.
Motor oil does not wear out-it just gets dirty-so recycling it saves a valuable resource
Less energy is required to produce a gallon of re-refined base stock than a base stock from crude
oil.
One gallon of used motor oil provides the same 2.5 quartz of lubricating oil as 42 gallons of crude
oil.
Used mineral oils are classified according to current European regulations as hazardous waste due to the
effects that they can have both on health and the environment. These effects include:
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Irritation of lung tissue due to the presence of gases that contain aldehydes, ketone, aromatic
compounds, etc.
The presence of chemical elements such as Cl (chlorine), NO2 (nitrogen dioxide), H2S (hydrogen
sulphide), Sb(antimony), Cr (chrome), Ni (nickel), Cd (cadmium) and Cu (copper) that affect the
upper respiratory tract and lung tissue.
They produce asphyxiating effects that prevent oxygen transportation due to their content of carbon
monoxide, halide solvents, hydrogen sulphide, etc.
Carcinogenic effects on the prostate and lungs due to the presence of metals such as lead, cadmium,
manganese, etc.
Direct effects on the environment that stand out include:
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The pollution of soils, rivers and the sea due to their low biodegradability.
On coming into contact with water, they produce a film that prevents oxygen circulation.
Uncontrolled combustion can lead to the emission of chlorine, lead and other gas elements into the
atmosphere, with the corresponding effects.
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Components in lubricating oil wastes are hydrocarbons, polymer additives, carbon particles, water and
metals (Mohammed, 2013). The content of metals in lubricating oil wastes is not derived from lubricant
base material but derives from additives added, metal, contaminants from petrol fuel containing lead, dust,
dirt from the air, refrigerant and cooling water used to cool the machine. The process of lubricating oil
wastes aims to make waste oil used to be a new oil that does not contain metal because the metal content
in used oil is not useful.
The different systems for treating oils once they have been rejected from the activity for which they were
produced.
After the oil has been used and has turned into used oil, the constituent pollutants that can be found are as
follows:
Table 1: Pollutant compounds in used oil
Pollutants
Examples
Polynuclear aromatic hydrocarbons
Mononuclear aromatic hydrocarbons
Dinuclear aromatic compounds
Chlorinated Hydrocarbons
Metals
Origin
Petroleum-Base Lubricant
Alkyl benzene
Petroleum-Base Lubricant
Napthalene
Petroleum-Base Lubricant
Trichloretane
Barium
Aluminium
Lead
Zinc, Chrome
Inorganic acids derived from chlorine, sulphur and nitrogen
Organic compounds such as aldehydes, acids, etc
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Use of contaminants
In additives
In engines
In fuel
The process by which used oil is generated appears in the diagram, together with the possible applications
for used oils.
Virgin Lubricating Oils
Handling and storage
Use of lubricating oils
Oil consumed during
use (<50%)
Oils that do not fulfil
specifications or are polluted
during handling and storage
Used oil that is potentially
recoverable (>50%)
Used oil indiscriminately
disposed of
Unused oil
Collected used oil
Incineration as special waste
Recycling/recovery
Figure 1. Process of generation of used oils
The percentage of used oil collected in relation to the total amount of oil that is potentially recoverable
varies a lot and depends on the countries and how well the collection logistics are organized. The values
are around 90 % in the best of cases, although on average, and for countries with efficient collection
logistics, these values can reach around 80%.
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Collection logistics
Systems for collecting oils are conditioned according to the types of production center. There are normally
a large number of collection points, and the quantities being collected are usually small. On the other hand,
the number of industries specializing in oil recovery and treatment is small so that each one has to cover an
extensive geographical area.
For the purposes of collection logistics, a distinction must be made between:
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The collection and initial storage of waste oil, which must be carried out at the points where it is
generated, i.e. industry, garages, etc.
Collection and transportation from the points where waste oil is generated to the treatment centers
or industries.
Used or waste oil is normally stored in containers prepared especially for this purpose. The principle upheld
is that it is the generator of the waste oil who is responsible for collecting and storing it in acceptable
environmental conditions.
An important criterion that needs to be underlined when organizing the systems of collection is that the
separation at source of different types of waste oils makes subsequent treatment processes easier and thus
increases the value of the waste oil oil because the levels of polluting substances in the end products are
also reduced at the same time. Unstructured collection systems (where different types of used oils are
collected) lead to more difficulties and involve a higher economic cost in later treatment and recovery
processes.
Collection systems therefore need to be organized according to the different sources where waste oil is
produced, with separation being carried out at source to make subsequent treatment processes easier and to
reduce their cost .(Enric Elias 2008)
The different types of waste oils have different applications and therefore different commercial values. The
higher the level of segregation at source, the higher the value of the waste oils, and the volume of oils that
are collected will therefore increase.
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Treatment and disposal of waste oil
The treatment and disposal of waste oil is very important because it reduces the toxicity of the waste. This
oil if not treated or carefully disposed of, has severe impacts on the environment because it contains
contaminants which if not carefully handled might cause soil and aquatic pollution which seriously affects
the ecosystem.
Many countries around the world have put in place regulations and sanctions for the handling of hazardous
waste, to be more specific, used waste oil.
Treatment processes
There are many treatment processes for used waste oil. These include;
A. Regeneration process: This allows for the production of premium quality waste oils. The waste oils
suitable for regeneration are those not heavily polluted and with a high viscosity index (HVI) such as engine
oil and hydraulic oils with or without Chlorine. (European Commission 2001). There are several processes
under the regeneration process
1) De-watering and de-fueling: This is the removal of water, light ends and fuel traces (naphtha10)
2) De-asphalting: this is the removal of asphaltic residues, heavy metals, polymers, additives and other
degradable compounds
3) Fractionation: (in two or 3 cuts)
4) Finishing: (hydro treatment), subjection to high pressure and temperatures which aims at reducing or
removing metals, metalloids, organic acids, compounds containing chlorine, sulphur and nitrogen
There are many regeneration techniques, some of which are listed below
i.Acid/Clay: De-watering with atmospheric vacuum stripping, de-asphalting with contact with sulphuric
acid and contact with absorption clay and fractionating with distillation unit then neutralization and
filtration
ii. Distillation/Clay: De-watering with atmospheric vacuum stripping and de-asphalting using content with
absorption clay.
iii. Distillation/Chemical treatment or solvent extraction technology: De-watering with vacuum distillation
(2nd stage) and de-asphalting with vacuum distillation (3rd stage), finishing with chemical treatment or
solvent extraction/
iv. Propane de-asphalting: De-watering using atmospheric vacuum stripping and de-asphalting with liquid
propane and fractionation with vacuum distillation, finishing with clay or hydro-treatment
v. Thermal de-asphalting (TDA): De-watering using atmospheric vacuum stripping + chemical treatment,
de-asphalting and fractionation with settling TDA, finishing with clay or hydro-treatment.
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B. Thermal Cracking: Thermal cracking is a refinery process well proven. (Taylor Nelson 2001) Thermal
cracking, visbreaking, catalytic cracking, fluid catalytic cracking, hydrocracking and coking are all
variations on the basis of the basic principle of breaking or cracking the large hydrocarbon molecules (CxHy
with 30 carbons) into smaller ones (CxHy with 10 to 18 carbons) by the application of sufficient heat in a
pressurized vessel. In this fashion, larger molecules of more viscous and less valuable hydrocarbons are
converted to less viscous and more valuable liquid fuels. The strategy of thermal cracking is to produce
high quality products ranging from demetallised heavy fuel oil to re-refined light industrial lube oil,
including gasoil products. Thermal cracking can accept various types of hydrocarbon feedstock: WO, waste
marine fuels, deep frying oils and, possibly with design considerations, waste plastics. Using thermal
cracking will produce a gasoil which
• is not odorous (no foul smelling),
• meets regulatory and consumer colour criteria,
• minimizes the formation of gums and tars during storage,
• is not highly acidic.
C. Re-use: There 2 methods to reclaim industrial lubricants before returning them to the users (Thomas,
2016);
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Laundering: This is a close-loop system especially for hydraulic and cutting waste oil. Solid
removal (filtration), de-watering and fresh additives allow to return the oil to its original form
again fit for use.
Reclamation: This is a recycling process especially from hydraulic waste oil. These oils are
simply centrifuged and/or filtered and then used, for instance, as mould release oil or base oil for
the production of chain saw oil.
D. Gasification: It consist in converting the carbon containing materials to synthetic gas (H2 and CO). It
presents the advantage of accepting mixed waste (waste oil and plastics). This process is not widely used
because large scale plants are necessary to reach the break-even point
E. Burning after severe re-processing: This process aims at separating the combustible waste oil portion
from the less desirable bottom fractions which contains the metals, the non-combustible ash, grit and dirt.
Some chemical treatment like acid/clay and solvent extraction can be used. The heavy distillate produced
can be burnt as marine diesel oil (MDO), fuel for heating plants.
F. Burning after mild re-processing: A simple cleaning process, to remove water and sediments is
required before further use of waste oil as replacement fuel oil (RFO) which can be used in
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Road stone plants: Reprocessed waste oil is burned to dry limestone and hard stone for the
manufacture of road surfacing materials in Belgium and the UK.
Fuel blending
Power stations: used as furnace start up fuel (Thomas, 2016)
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G. Burning in cement kilns: Cement kilns are very energy intensive. Because of cost, waste oil is
advantageous for use. Not all national regulations accept the burning of waste oil in cement kiln but its
accepted in Germany, France, Italy and the UK. Cement kilns have integrated collectors to secure their
supplies (Taylor, 2001).
H. Other direct burning: Burning waste oil without any pre- treatment is one disposal option with several
different methods of energy recovery:
-burning waste oil in cement kilns
-burning waste oil in municipal waste incinerators and chemical waste incinerators. Some municipal
waste incinerators recover energy for power generation or district heating. Most of chemical waste
incinerators recover energy to be fed back into the operational energy required for the incinerator itself
(replacement of gas or gasoil)
Table 2: types of waste oil and the type of treatment methods used and the products generated from the
treatment process;
Waste oil
Clean waste oil
Type of treatment
Re-use
Products
Hydraulic or cutting oil
-electricity companies
-Shipping industry
Engine waste oil and clean waste Regeneration or re-refining
oil
All types of waste oil including Thermal cracking
synthetic oils
-Major engineering companies
mould oil or base oil for the
production of chain saw oil
Lubricant base oil
Distillation gas oil products
-Gas oil
-De-metalized fuel oil
-Marine gas oil
-Re-refined light base oil
Mixed waste
Gasification
Synthetic gas
-hydrogen
All types of waste oil especially Severe re-reprocessing
heavy polluted ones
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-methanol
De-metalized fuel oil
-marine diesel fuel
-fuel for heating fuel
Mild reprocessing then burning
Replacement fuel oil
-road stone plants, cement kilns,
large marine engines, pulverized
power stations
Direct
burning
(waste
incinerators,
cement
kilns,
greenhouses, workshops)
Storage
Waste oil storage is an important aspect in the management of waste oil. In many countries, there are
regulations put in place for the storage of waste oil. Storage facilities are built and some company do storage
as a job. The regulations specify the various types of waste and their storage site and the type of
containment. Storage of waste oil is either done onsite (where it is produced) or offsite (transferred to
another facility) for storage to avoid spillage which is the major problem of waste oil.
Waste oil is either stored in above ground storage or underground storage in strong containers or tanks that
will not leak or burst in ordinary use. The storage facilities are monitored to avoid spillage and must have
a secondary containment either with the primary tank enclosed in a second outer tank (integrally bounded)
or in the form of an impermeable bund surrounding the tank auxiliary pipework and safety devices.
CONCLUSION
Although waste oil is considered hazardous, and the fact oil is in high demand and it’s not a renewable
resource, many technologies have been developed to reprocess waste oil and recycle it for many other
different uses, if not for its same purpose. This technologies reduce the quantity of waste oil and in some
ways protect the environment from waste oil pollution.
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