Used Oil Re-Refining Techniques in Nigeria-Economic · PDF fileUsed Oil Re-Refining Techniques in Nigeria-Economic Benefits ... used oil to new oil by removing water, dirt, heavy metals

VOL. 6, NO. 2, February 2016 ISSN 2225-7217

ARPN Journal of Science and Technology ©2011-2016. All rights reserved.

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Used Oil Re-Refining Techniques in Nigeria-Economic Benefits *1 Lukman Animashaun, 2 Adekunle Yekinni, 3 Bethan Warren

1,2 Department of Mechanical Engineering, Lagos State Polytechnic, Ikorodu, Lagos 3 School of Mechanical Engineering, Institute of Functional Surfaces, University of Leeds, UK.

* Corresponding Author:

ABSTRACT The basic functions of lubricating oil in machines are to minimize friction and wear in order to enhance their life-span of

machines. When lubricating oils have been used beyond their recommended life span, improper disposal can be harmful to

the environment. In this paper, used oil sources and different collection techniques were identified with the objective to

show that enhanced collection rate could stimulate used oil re-refining. Based on various used oil re-refining techniques, a

program was formulated that will not place the burden of disposal only at the door step of the facilities generating the

waste oil alone, but also as the collective responsibility of the government and the waste oil processing program

managements. An empirical relationship was obtained for the economic benefit in terms of, the amount of waste oil

drained per car per year and the collection rate of waste oil for any given year above 2009.

Keywords: Lubricant additives, Recycling, Re-refining, Feed stock, Do-it-yourselfers, Do-it-for-me’s

1. INTRODUCTION Lubricating oils are viscous liquids used to

lubricate moving parts of machines and engines. These

oils are mainly composed of complex mixtures of

hydrocarbon molecules and inorganic additives in order to

protect rubbing surfaces from friction, wear and excessive

heating. In addition, further desirable properties of

lubricating oils are sealing of spaces and engine

cleanliness. Lubricating oils can be categorized into;

semi-solid lubricating greases, automotive oils and

industrial lubricating oils.

Lubricating oils are produced during crude oil

refining to give base oil or base stock which is blended

with additives. The lubricant base oil could be either

mineral oil or synthetic base oil (Poly alpha Olefin etc.).

In order to meet the desired functions of these

lubricants under high loads, chemical agents called

additives are added to the base oil at low concentration in

order to reinforce or impact their function by either

interacting chemically or physically with engine metallic

surfaces. These additives can be; antiwear/EP, friction

modifier, oxidation inhibitor, corrosion and rust inhibitor,

dispersant, detergent, viscosity index improver, pour point

depressant, storage inhibitor and foam inhibitor to give

what is known as fully formulated oil.

When fully formulated oil is put into an internal

combustion engine for use, it is essentially degraded by

heating and oxidation to breakdown the additives for

optimum lubrication performance. However, after about

5,000 kilometers of engine use, these additives can no

longer provide desired functions expected of it. Hence, it

is drained off the engine to become what is known as used

oil. Used motor oil is a hazardous waste that is known to

contain heavy metals, contaminants and dirt discarded by

the engine during use. A study of fresh fully formulated

oil with low concentration of heavy metals such as;

Vanadium (V), Lead (Pb), Aluminum (Al), Nickel (Ni)

and Iron (Fe) gave higher concentration in the spent oil

(Adebiyi, Oluyemi, & Peter, 2011; Anoliefo, Ikhajiagbe,

Okonofhua, & Diafe, 2006). Used oil is only dirty but not

worn out, hence the need for re-refining

The main sources of used oils in Nigeria was

categorized as; transportation, industry and private

electricity generation (Anoliefo et al., 2006; Bamiro &

Osibanjo, 2004). Worldwide demand for lubricating oils

for industrial processes, passenger and heavy goods

vehicles was estimated to be about 51.3 billion

liters(Anoliefo et al., 2006; Szramka, 1994). Annual

volume of used oil in Nigeria was estimated as 150

million liters with only about 90 million liters available

for processing based on 30 % collectible (Bamiro &

Osibanjo, 2004).

A convenient way of disposing used oil by auto-

technician and allied artesian is disposal into gutters, open

vacant plots and waterways. This practice can lead to

environmental problems, risk to human health and plants

including microbial activity and fertility in soil (Anoliefo

et al., 2006; McGrath, Chaudri, & Giller, 1995). Another

means of disposing used oil is by burning in furnaces to

generate heat or in power plants to generate electricity. A

blend of used oil can be used; as marine fuel, asphalts

mixture for road paving or used for industrial plant

boilers, space heaters and other industrial heating

applications such as cement kilns and blast furnace whose

product of combustion can exacerbate air pollution

problems. Used oil re-refining is a process of restoring

used oil to new oil by removing water, dirt, heavy metals

and chemical impurities.

This paper will assess the economic benefits of

enhanced management of used oil from increasing motor

vehicle growth.

The objectives of this paper are to;

Literature review on the existing

techniques/procedure/schemes

[email protected]




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Proposed techniques for used lubrication oil

recycling

Project motor vehicle growth rate

Establish an economic relationship between

increased used oil processing, number of

vehicles and number of liters of used oil from

cars per service per year.

2. LITERATURE REVIEW OF THE

EXISTING TECHNIQUES /

PROCEDURE / SCHEMES

Used lubricating oil management involves;

1. Collection

2. Re-refining in lubricating oil recovery

3. Re-refining in dedicated grass-root unit

4. Reprocessing in primary refinery

5. Reprocessing to fuel

6. Burning untreated used oil

7. Disposal

In order to conserve the original properties of the

oil for possible re-use, the most feasible first option of re-

refining lubricating oil is recovery. This can be

accomplished through re-refining, recycling and/ or

destruction. Re-refined used engine oil implies using

additional treatment processes to remove soluble and

insoluble impurities, while recycled or reconditioned used

engine oils implies using commercial filtration processes

to remove insoluble impurities

Figure 1 (a) and (b) shows the schematic diagram

of different types of basic used oil refining plants with

Figure 2 indicating typical re-refined used oil is as shown

in compares to used oil.

2.1 Reprocessing

The aim is to produce an end product that is low

in basic sediment and water content with the primary

purpose of not clogging sediment build-up in customer

tanks or system during use. Hence, this is a physical

treatment process that involves settling, filtration or a

combination of these operations. However, these

processes are not sufficient to remove all chemical

contaminants; hence the inclusion of other processes such

as clay contacting and distillation could produce better

results

2.2 Re-refining

This type of used oil recycling involves among

many other options; pre-treatment by filtration, vacuum

distillation with clay contacting. The other option involves

solvent extraction with clay and chemical treatment by

hydro-heating. A typical used oil processing steps is

summarized in Figure 2.

(a)

(b)

Figure 1:Schematic diagram of (a) solvent extraction/clay re-refining used oil processing and (b) acid treatment/clay-

percolation used oil re-refining process(Emam & Shoaib, 2012)




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A typical used oil processing steps is summarized in Figure 2.

Figure 2:Used oil processing steps (Harrison, 1994)

2.3 Incineration

When the waste oil is tested to be highly

contaminated with polychlorinated biphenyls (PCB) and

polychlorinated terphenyls (PCT), this method of waste

management offers the best choice. Hazardous waste

incinerators or controlled high-temperature at cement

factories can be used to eliminate organics and

neutralize acids at temperatures in excess of 2400 oC with

continuous monitoring of gas emissions (Arnaout, 1997).

In this way, the amount of heavy metal is expected to be

greatly reduced. A comparison of used oil to re-refined

used oil is as shown in Figure 3,

Figure 3:A typical used oil is contained in the right bottle and left bottle contain re-refined oil (Merai Yash)




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2.4 Used Oil Processing in Nigeria

An extensive study of used oil processing in

Nigeria was conducted by (Bamiro & Osibanjo, 2004)

where the various waste management options considered

is as shown in Figure 4.

Two companies and one government agency

were identified to have attempted to process used oil.

However, these attempts had not yielded desired results

due to financial and technological factors. In addition, a

major constraint towards achieving desired goals by

different companies is the availability of sufficient

quantity and quality of used oil as feedstock. In view of

problems regarding feedstock supply at the right quality

and quantity, poor waste lubricating oil collection

management appears to be a major challenge that needs to

be addressed in order to encourage used oil re-refining in

Nigeria.

Figure 4:Used oil management options for Nigeria(Bamiro & Osibanjo, 2004)

2.5 Type of Products and By-Products

This phase involves targeting customers in order

to make economic decisions. The two primary options are

to recycle used oil to virgin quality base oil market or

distillate fuel requirement (marine diesel oil used to power

medium speed engines). The by-products of used oil

processing plant is as summarized in Figure 5.




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Figure 5:Used oil processing steps (Harrison, 1994)

3. FORMULATING USED OIL RE-

REFINING PROGRAM There are two types of people that used oil can

be obtained from. These are do-it-yourselfers and do-it-

for-me’s. Those that change their own oil themselves in

order to save money or take pride in the quality of their

own workmanship are do-it-yourselfers, while do-it-for-

me’s have their oil changed at service stations and other

mechanic places or quick lubes. About 30% of motorists

are known to change their own oil based on a survey,

hence it is important that do-it-yourselfers are encouraged

to re-refining their used oils. In order to encourage this

category of used oil sources, oil waste lubricating oil re-

refining programs need to be located throughout every

locality. Urban areas are particularly in need of this type

of program as more motor oil is used in these areas due to

the large number of vehicles in these areas.

Used oil sources will have to collect used oils in

leak-proof container with secure screw-on top lids. For

do-it-yourselfers, they may choose to reuse the oil’s

original container or utilize another household container

that can prevent leakage or spillage, while for do-it-for-

me’s, large containers like drums are necessary due to

higher volume of generation. The various sources of used

oil are summarized in Figure 6. The challenge is how used

oils can be collected from various sources.

Three approaches could be necessary in order to

meet this challenge; use of curbside collection program

where regular garbage trucks are adapted with metal

storage tanks (this collection program is most suitable for

metropolitan areas), use of service stations, garages and

automotive service centres, and drum collection program

where 55 liters drums are place for collection (most

suitable for rural areas with few service stations or

garages or premises of businesses and government

agencies.

In formulating successful used oil processing

programs, positive economics and reliable technology are

necessary since it involves environmentally unfriendly

waste to a valuable product with motivating factors that

include concern for environmental and legislative

restrictions. In this program, consideration must be given

to the charge stock availability, type of products and by-

products that will be produced from different processes.




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Figure 6:Used oil sources (Andrews, 2008)

3.1 Feed Stock Characteristics

The quality of used oil is certainly variable

which unlike most refineries has reasonably consistent

feed quality. Used oil quality is a function of the materials

dumped into it which can be contaminants, collection

system, and type of sample monitoring and testing.

Contaminates can range from gasoline and diesel

from internal combustion engines, synthetic motor oils,

water, wear metals, tank bottoms, soot and so on. A

method of minimizing the variable quality of used oil is

by collection in larger lots in big tanks in order to

homogenize the final quality.

3.2 Engineering Challenge in Process Facility Design

Used oil by its nature is very corrosive under

certain operating conditions as it contains organic and

naphthenic acids which could be as a result of the

followings; by-products of internal combustion engines,

naturally acids inherent in the oil or acid introduced from

external sources. The resulting effect of these acids on

processing tanks often cause rapid and catastrophic

corrosion failures and /or gradual metal corrosion, hence

the use of some corrosion resistance material without

sacrificing other engineering requirements. In addition,

energy is required to be provided for the heaters and the

entire plant.

3.3 Used Oil Collection Program

This program is essential for any used oil re-

refining processing plans. Figure 7 indicated a generalized

model for used oil collection schemes in order to ensure

adequate supply. A study of collection methods from

different countries around the world revealed that the

Japanese approach will be most suitable for Nigeria. This

approach requires the public to turn in their used oil in

order to buy a new one. In addition, the local government

cooperates with local residence’ association, gas stations

and companies to form small scale generators of waste

oils who forwards the collected used oil to a central

collection centre; State Governments Waste Management

Authorities in Nigeria lubricating oil collection program.

However, a key element in the collection chain is

the carrier or transporter who undertakes used oil

transportation between the small scale generator and

regional collection centre or between the regional

collection centre and the central collection station




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Figure 7:Multi-layered used lubricating oil collection scheme (Andrews, 2008)

3.4 Public Awareness

Used oil collection programs could be enhanced

with increasing publicity through the print and electronic

media to educate and inform the public on how and where

to dispose of their waste lubricating oils and filters. In

addition to these, visual displays could be made on how

used oil should be handled and transferred to collection

sites by automobile parts stores and auto-repair shops.

The public need to be aware of the consequences of

improperly disposed used oil.

3.5 Legislative Support

A cursory view of the legislative instruments for

used oil management in Nigeria as reviewed by (Bamiro

& Osibanjo, 2004)indicated a generalized approach that

gives loopholes to would be offenders. Section (1) of

Regulation 5.1.9 of 1991 regulating pollution abatement

in industries and facilities in Nigeria stipulates that ‘No

oil in any form shall be discharged into public drain,

rivers, lakes, sea or underground injection without a

permit issued by an agency or organization designated by

the Government. Section 11 subsection (1) further stated

that collection, treatment, transportation and final disposal

of waste shall be the responsibility of the industry or

facility generating the waste(Bamiro & Osibanjo, 2004).

A loophole in this legislation is the non-

prohibition of waste disposal on landfill site. An

understandable point here is that most of the present solid

waste management in the country is based on disposal on

landfill sites which pose a health and safety risk to the

public. In addition, placing the responsibility of disposal

solely on the door-step of the facilities generating this

waste leaves room for disposal by burning that can result

in air pollution and threat to public safety. Hence any used

oil collection program will likely fail based on this one-

sided responsibility.

4. SIMULATION STUDIES FOR

EVALUATING THE PERFORMANCE

OF ENHANCED COLLECTION RATE

4.1 Methodology

In this simulation study, oil generation rate from

vehicle based on historical data from the works of

Appendix 1(Chukwu, Isa, Ojosu, & Olayande, 2015) and

Appendix 2 (Badmus, Osunleke, Fagbenle, & Oyewola,

2012). An average of six possibilities is used to predicting

vehicle growth rate, by considering a three year growth

rate (3.3 1% due to economic factors) against two year

decline rate (12.5 1.7 %) in every ten year cycle. In




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addition, we assume that used engine oil from every car

serviced after covering 5000 km journey yields two used

oil scenarios; 0.5 liters yield (scenario 1) and1 liter yield

(scenario 2). However, annual distance covered by an

average car in Nigeria had been estimated as 18,300 km

(Oke, 2012). Hence every car is expected to be serviced

about 4 times in a year with two likely scenarios defined

as;

Scenario 1; 0.5 liter of used oil per service to

give 2 liters of used oil per year.

Scenario 2;1 liter of used oil per service to give 4

liters of used oil per year

Collection rates of 30% had initially been

obtained by (Bamiro & Osibanjo, 2004). In this study,

simulation studies of the economic effect of improving the

collection rate to 40, 50, 60, 70, 80 and 90% will be

considered. This will be achieved by determining

quantities of re-refined oil in liters and obtaining the

equivalent amount of crude oil that will be required to

refine the same quantities of re-refined oil using the fact

that 42 gallons of crude oil is required to produce 2.37

liters of lubricating oil that one gallon of re-refined oil

will make (April & Powell, 1994).The economic benefit

has been shown by the number of barrels of crude oil that

would need to be purchased if the waste oil was not re-

refined.

4.2 Results and Discussions

The result of the estimated economic benefits as

shown in Table 1 and Table 2 was plotted against time. A

typical plotis shown in Figure 8 for scenario 1; an

identical plot was obtained for scenario 2, but is not

shown here.




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Table 1: Economic benefit from used oil re-refining from 30 to 50% collection rates




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Table 2: Economic benefits from used oil re-refining from 60 to 90% collection rates

A typical plot is shown in Figure 8 for scenario

1; an identical plot was obtained for scenario 2, but is not

shown here. An empirical relationship was obtained for

the economic benefit in terms of the amount of waste oil

drained per car per year (L), the collection rate of waste

oil as a decimal (i.e. 30% is 0.3) and the year (y), where y

≥ 2009.As seen in equation 1.

Equation 1




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Figure 8:A typical economic benefit curves for scenario 1 up to year 2050

Figure 9:Assessment of economic cost comparison for the two scenarios

Figure 9 indicates the economic benefit of

scenario 1 and scenario 2, between 30% and 90%

collection rate in both cases. The overlapping region

indicates at which percentage collections would be

equivalent for the different drain amounts suggested by

each scenario.

Hence, scenario 2 appeared to be the most

economically feasible options where 1 liter of used oil per

vehicle serviced is collected for processing. A limitation

to this study is technological advancement in engine oil

formulation that provides for longer engine oil drain

intervals in vehicles. Although the equation presented is

unable to link the number of barrels of oil required to a

specific year, it holds true for any number of vehicles,

therefore if a different model for the vehicle growth were

used the equation would still provide a value for the

economic benefit.




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5. CONCLUSIONS A successful used oil re-refining program is

imperative in view of the increasing demands of

petroleum products to power industrial machines and

internal combustion engines. Towards this end,

government assistance will be needed in making positive

societal impact for used oil re-refining program. The

result of this study elucidate economic benefits from used

oil re-refining in terms of reduction of imported

lubricating oil, conservation of oil resource, employment

generation, provide eco-friendly disposal of hazardous

waste and revenue generation. The result of this study

indicated the need to improve the present used oil

collection rates as a way of stimulating investment in used

oil re-refining in the country.

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APPENDIX 1

APPENDIX 2

Documents

Used Oil Re-Refining Techniques in Nigeria-Economic · PDF fileUsed Oil Re-Refining Techniques in Nigeria-Economic Benefits ... used oil to new oil by removing water, dirt, heavy metals