Re-refining of used Lube oils

A Seminar Report

Submitted by-

Mr. Shyambahadur Yadav, B.E. (Chem.)

In partial fulfillment for the award of the degree

Of

BACHELOR OF ENGINEERING

IN

CHEMICAL ENGINEERING

Under the guidance of

Prof. Ananya Dey

DEPARTMENT OF CHEMICAL ENGINEERING

 SHIVAJIRAO.S.JONDHALE COLLEGE OF ENGINEERING,

DOMBIVLI (EAST) – 421203

UNIVERSITY OF MUMBAI

2012-2013

SHIVAJIRAO.S.JONDHALE COLLEGE OF ENGINEERING,

DEPARTMENT OF CHEMICAL ENGINEERING

DOMBIVLI (EAST) – 421203

CERTIFICATE

This is to certify that the Seminar report entitled “Re-refining of used Lube

oils” carried out by Mr.Shyambahadur Yadav of B.E. Chemical Engineering, during the

academic year 2012 – 2013, is a bonafide work submitted to the Department of Chemical

Engineering of Shri. Shivajirao.S.Jondhale College of Engineering.

Seminar Guide Internal Examiner External Examiner

Head of Department Dr. J. W. Bakal

Chemical Engg. Dept. Principal

INDEX

CHAPTER CONTENT

1 INTRODUCTION

2 HISTORY

3 LITERATURE REVIEW

3.1 PROPERTIES

3.2 TYPES

3.3 ADDITIVES

3.4 CONTAMINANTS IN USED LUBE OIL

3.5 ENVIRONMENTAL IMPACT

3.6 VACUUM DISTILLATION PROCESS OF REFINING

3.7 ADVANTAGE OF RE-REFINING

3.8 APPLICATION

4 CONCLUSION

REFERENCES

CHAPTER 1

INTRODUCTION

Lubricating oil is the type of petroleum product which is employed to reduce wear of

one or both surfaces in close proximity, and moving relative to each another in an engine

or machine. It is also called as engine oil. Its viscosity is comparatively higher than the

other petroleum products. It is manufactured by refining the petroleum by atmospheric or

vacuum distillation process. Typically lubricants contain 90% base oil (most often

petroleum fractions, called minerals oil) and less than 10% additives.

If one thinks of lubricants today, the first type to come to mind are mineral oilbased.

Mineral oil components continue to form the quantitatively most important foundation of

lubricants. Petrochemical components and increasingly derivatives of natural, harvestable

raw materials from the oleo-chemical industry are finding increasing acceptance because

of their environmental compatibility and some technical advantages.

On average, lubricating oils, which quantitatively account for about 90% of lubricant

consumption, consist of about 93% base oils and 7% chemical additives and other

components (between 0.5 and 40 %). The development of lubricants is closely linked to

the specific applications and application methods. As a simple description of materials in

this field makes little sense, the following sections will consider both lubricants and their

application.

CHAPTER 2

HISTORY

The oil re-refining industry has existed for many years and has evolved over time, being

subject to pressures from both industry and society. In the early years, used oil was

sometimes filtered and re-used, but most often it was dumped on the ground and in water,

and occasionally burned as a fuel. Over time, efforts were made to recover spent oil, and

by the mid-1960’s, there were more than 100 small companies reprocessing over one

hundred million gallons of used oil annually in the United States. These companies

generally employed the “acid/clay” re-refining process, wherein a large amount of

sulfuric acid and clay was used to treat the used oil. Although the technology produced an

acceptable, but sub-standard base oil, it also created substantial hazardous waste by-

products, including acid-tar and oil saturated clay.   Many of these original acid/clay

facilities became “super-fund” clean-up sites.

Starting in the 1970s, the use of acid clay re-refining was discouraged by environmental

regulators and is currently outlawed in most countries around the world. In the late

1970’s, alternative processes were developed to treat the used oil in a more

environmentally friendly manner. By and large these efforts were spearheaded by used

oil gatherers who needed a means of “disposing” of the oil they gathered. Their primary

revenue stream was generated through the charges levied in collecting the oil. Once

collected, they needed an economic means of turning it into an environmentally

acceptable, salable product. Their focus was not on creating high quality products but

rather in treating a waste stream to market it for higher value.

The first of the “next-generation” technologies was the Phillips Re-Refined Oil Process

(PROP). This technology was developed during the energy crunch of the 1970s as a

potential solution for recovering the base oil from used oil. This technology involved “de-

metalizing” the oil (effectively removing the metals) with diammonium phosphate, which

created a metal phosphate precipitate. The oil was then filtered, distilled and hydro-

treated. The PROP technology was successful in producing low quality base oils;

however, there were several environmental concerns that arose due to the need to dispose

of large quantities of oil soaked, heavy metal laden, precipitate and filter media. One of

the purchasers of the technology was Mohawk Oil in Canada. Once Mohawk understood

the shortcomings of the PROP technology, they decided to modify it (by removing the

de-metallization section and adding a wiped film evaporator and a different chemical

treatment regimen), thereby creating a novel process. Mohawk’s innovations where

further adapted by Evergreen Oil (California) and Safety-Kleen Systems Inc.. (Illinois) in

the United States and formed the basis for the technology that is currently being used by

these companies.  

Although there are many types of lube oils to choose from, mineral oils are the most

commonly used because the supply of crude oil has rendered them inexpensive;

moreover, a large body of data on their properties and use already exists. Another

advantage of mineral-based lube oils is that they can be produced in a wide range of

viscosities—viscosity refers to the substance's resistance to flow—for diverse

applications. They range from low-viscosity oils, which consist of hydrogen-carbon

chains with molecular weights of around 200 atomic mass units (amu), to highly viscous

lubricants with molecular weights as high as 1000 amu. Mineral-based oils with different

viscosities can even be blended together to improve their performance in a given

application. The common 1OW-30 motor oil, for example, is a blend of low viscous oil

(for easy starting at low temperatures) and highly viscous oil (for better motor protection

at normal running temperatures).

First used in the aerospace industry, synthetic lubricants are usually formulated for a

specific application to which mineral oils are ill-suited. For example, synthetics are used

where extremely high operating temperatures are encountered or where the lube oil must

be fire resist.

Waste / Used oil is generally referred to Petroleum oil, which has lost its required

properties and therefore cannot be used as such for any application in its present form.

Every year large quantities of waste s, Fuel and metallic particles that create the need for

oil replacement. It is also very hazardous for environment.

CHAPTER 3

3.1 PROPERTIES OF LUBRICATING OIL

Lubricating oils are fluids such as engine oils, gear, hydraulic oils, turbine oils, etc. The

properties of lubricating oil are, keeping moving parts apart, reduce friction, transfer heat

carry away contaminants & debris, transmit power, protect against wear, prevent

corrosion, seal for gases, stop the risk of smoke and fire of objects, prevent rust.

Keep moving parts apart

Lubricants are typically used to separate moving parts in a system. This has the benefit of

reducing friction and surface fatigue, together with reduced heat generation, operating

noise and vibrations. Lubricants achieve this by several ways. The most common is by

forming a physical barrier i.e., a thin layer of lubricant separates the moving parts. This is

analogous to hydroplaning; the loss of friction observed when a car tire is separated from

the road surface by moving through standing water. This is termed hydrodynamic

lubrication. In cases of high surface pressures or temperatures, the fluid film is much

thinner and some of the forces are transmitted between the surfaces through the lubricant.

Reduce friction

Typically the lubricant-to-surface friction is much less than surface-to-surface friction in

a system without any lubrication. Thus use of a lubricant reduces the overall system

friction. Reduced friction has the benefit of reducing heat generation and reduced

formation of wear particles as well as improved efficiency. Lubricants may contain

additives known as friction modifiers that chemically bind to metal surfaces to reduce

surface friction even when there is insufficient bulk lubricant present for hydrodynamic

lubrication, e.g. protecting the valve train in a car engine at startup.

Transfer heat

Both gas and liquid lubricants can transfer heat. However, liquid lubricants are much

more effective on account of their high specific heat capacity. Typically the liquid

lubricant is constantly circulated to and from a cooler part of the system, although

lubricants may be used to warm as well as to cool when a regulated temperature is

required. This circulating flow also determines the amount of heat that is carried away in

any given unit of time. High flow systems can carry away a lot of heat and have the

additional benefit of reducing the thermal stress on the lubricant. Thus lower cost liquid

lubricants may be used. The primary drawback is that high flows typically require larger

sumps and bigger cooling units. A secondary drawback is that a high flow system that

relies on the flow rate to protect the lubricant from thermal stress is susceptible to

catastrophic failure during sudden system shut downs. An automotive oil-cooled

turbocharger is a typical example. Turbochargers get red hot during operation and the oil

that is cooling them only survives as its residence time in the system is very short i.e.

high flow rate. If the system is shut down suddenly (pulling into a service area after a

high speed drive and stopping the engine) the oil that is in the turbo charger immediately

oxidizes and will clog the oil ways with deposits. Over time these deposits can

completely block the oil ways, reducing the cooling with the result that the turbo charger

experiences total failure typically with seized bearing. Non-flowing lubricants such as

greases & pastes are not effective at heat transfer although they do contribute by reducing

the generation of heat in the first place.

Carry away contamination

Lubricant circulation systems have the benefit of carrying away internally generated

debris and external contaminants that get introduced into the system to a filter where they

can be removed. Lubricants for machines that regularly generate debris or contaminants

such as automotive engines typically contain detergent and dispersant additives to assist

in debris and contaminant transport to the filter and removal. Over time the filter will get

clogged and require cleaning or replacement, hence the recommendation to change a car's

oil filter at the same time as changing the oil. In closed systems such as gear boxes the

filter may be supplemented by a magnet to attract any iron fines that get created.

It is apparent that in a circulatory system the oil will only be as clean as the filter can

make it, thus it is unfortunate that there are no industry standards by which consumers

can readily assess the filtering ability of various automotive filters. Poor filtration

significantly reduces the life of the machine (engine) as well as making the system

inefficient.

Transmit heat

Lubricants known as hydraulic fluid are used as the working fluid in hydrostatic power

transmission. Hydraulic fluids comprise a large portion of all lubricants produced in the

world. The automatic transmission's torque converter is another important application for

power transmission with lubricants.

Protect against wear

Lubricants prevent wear by keeping the moving parts apart. Lubricants may also contain

anti-wear or extreme pressure additives to boost their performance against wear and

fatigue.

Prevent corrosion

Good quality lubricants are typically formulated with additives that form chemical bonds

with surfaces, or exclude moisture, to prevent corrosion and rust.

Seal for gases

Lubricants will occupy the clearance between moving parts through the capillary force,

thus sealing the clearance. This effect can be used to seal pistons and shafts

Some other properties of lubricating oil are given below:

UNIT VISCOSITY

(CST)

FLASH

POINT

(°C)

FIRE

POINT

(°C)

POUR

POINT

(°C)

VISCOSITY

INDEX

DENSITY

(Kg/m^3)

ENGINE

OIL

40 150 170 -46 85 880

VISCOSITY

The viscosity of oil is its tendency to resist flow. A liquid of high viscosity flows very

slowly. In variable climates, for example, automobile owners change oil according to

prevailing seasons. Oil changes are necessary because heavy oil becomes too thick or

sluggish in cold weather, and light oil becomes too thin in hot weather. The higher the

temperature of an oil, the lower its viscosity becomes; lowering the temperature increases

the viscosity. On a cold morning, it is the high viscosity or stiffness of the lube oil that

makes an automobile engine difficult to start. The viscosity must always be high enough

to keep a good oil film between the moving parts. Otherwise, friction will increase,

resulting in power loss and rapid wear on

the parts.

FLASH POINT

The flash point of an oil is the temperature at which enough vapor is given off to flash

when a flame or spark is present. The minimum flash points allowed for Navy lube oils

are all above 300°F. However, the temperatures of the oils are always far below 300°F

under normal operating conditions.

FIRE POINT

. The fire point of a fuel is the temperature at which it will continue to burn for at least 5

seconds after ignition by an open flame. At the flash point, a lower temperature, a

substance will ignite briefly, but vapor might not be produced at a rate to sustain the fire.

Most tables of material properties will only list material flash points, but in general the

fire points can be assumed to be about 10 °C higher than the flash points. However, this

is no substitute for testing if the fire point is safety critical.

AUTOIGNITION POINT

The auto-ignition point of an oil is the temperature at which the flammable vapors given

off from the oil will burn. This kind of burning will occur without the application of a

spark or flame. For most lubricating oils, this temperature is in the range of 465° to

815°F.

POUR POINT

The pour point of a liquid is the lowest temperature at which it becomes semi solid and

loses its flow characteristics. In crude oil a high pour point is generally associated with

high paraffin content, typically found in crude deriving from a larger proportion of plant

material. That type of crude oil is mainly derived from a kerogen Type II.

3.2 TYPES OF LUBRICATING OIL

In 1999, an estimated 37,300,000 tons of lubricants were consumed worldwide.

Automotive applications dominate, but other industrial, marine, and metal working

applications are also big consumers of lubricants. Although air and other gas-based

lubricants are known, e.g., in fluid bearings), liquid and solid lubricants dominate the

market, especially the former.

Lubricants are generally composed of a majority of base oil plus a variety of additives to

impart desirable characteristics. Although generally lubricants are based on one type of

base oil, mixtures of the base oils also are used to meet performance requirements.

Base oil group

Mineral oil term is used to encompass lubricating base oil derived from crude oil. The

American Petroleum Institute (API) designates several types of lubricant base oil:

a) Group I – Saturates <90% and/or sulfur >0.03%, and Society of Automotive

Engineers (SAE) viscosity index (VI) of 80 to 120. Manufactured by solvent

extraction, solvent or catalytic dewaxing, and hydro-finishing processes. Common

Group I base oil are 150SN (solvent neutral), 500SN, and 150BS (brightstock)

b) Group II – Saturates over 90% and sulfur under 0.03%, and SAE viscosity index

of 80 to 120. Manufactured by hydrocracking and solvent or catalytic dewaxing

processes. Group II base oil has superior anti-oxidation properties since virtually

all hydrocarbon molecules are saturated. It has water-white color.

c) Group III – Saturates > 90%, sulfur <0.03%, and SAE viscosity index over 120.

Manufactured by special processes such as isohydromerization. Can be

manufactured from base oil or sax wax from dewaxing process.

d) Group IV – Polyalphaolefins (PAO)

e) Group V – All others not included above such as naphthenics, PAG, esters.

In North America, Groups III, IV and V are now described as synthetic lubricants,

with group III frequently described as synthesised hydrocarbons, or SHCs. In

Europe, only Groups IV and V may be classed as synthetics.

The lubricant industry commonly extends this group terminology to include:

a) Group I+ with a Viscosity Index of 103–108

b) Group II+ with a Viscosity Index of 113–119

c) Group III+ with a Viscosity Index of at least 140

Can also be classified into three categories depending on the prevailing compositions:

a) Paraffinic

b) Naphthenic

c) Aromatic

Lubricants for internal combustion engines contain additives to reduce oxidation

and improve lubrication. The main constituent of such lubricant product is called

the base oil, base stock. While it is advantageous to have a high-grade base oil in

a lubricant, proper selection of the lubricant additives is equally as important.

Thus some poorly selected formulation of PAO lubricant may not last as long as

more expensive formulation of Group III+ lubricant.

3.3 ADDITIVES

A large number of additives are used to impart performance characteristics to the

lubricants. The main families of additives are:

a) Antioxidants

b) Detergents

c) Anti-wear

d) Metal deactivators

e) Corrosion inhibitors, Rust inhibitors

f) Friction modifiers

g) Extreme Pressure

h) Anti-foaming agents

i) Viscosity index improvers

j) Demulsifying/Emulsifying

k) Stickiness improver, provide adhesive property towards tool surface (in

metalworking)

l) Complexing agent (in case of greases)

Note that many of the basic chemical compounds used as detergents (example: calcium

sulfonate) serve the purpose of the first seven items in the list as well. Usually it is not

economically or technically feasible to use a single do-it-all additive compound. Oils for

hypoid gear lubrication will contain high content of EP additives. Grease lubricants may

contain large amount of solid particle friction modifiers, such as graphite, molybdenum

sulfide.

3.4 IMPACT OF USED LUBE OIL ON HEALTH AND ENVIRONMENT

A release of used oil to the environment, whether by accident or otherwise, threatens

ground and surface waters with oil contamination there by endangering drinking water

supply and aquatic organisms.

Used oil can damage the environment in several different ways:

a) Spilled oil tends to accumulate in the environment, causing soil and water

pollution. Oil decomposes very slowly. It reduces the oxygen supply to the micro-

organisms that break the oil down into non-hazardous compounds.

b) Toxic gases and harmful metallic dust particles are produced by the ordinary

combustion of used oil. The high concentration of metal ions, lead, zinc,

chromium and copper in used oil can be toxic to ecological systems and to human

health if they are emitted from the exhaust stack of uncontrolled burners and

furnaces.

c) Some of the additives used in lubricants can contaminate the environment. E.g.

zinc dialkyl dithiophosphates, molybdenum disulphide, and other organo-metallic

compounds.

d) Certain compounds in used oil - eg poly-aromatic hydrocarbons (PAH) - can be

very dangerous to one's health. Some are carcinogenic and mutagenic. The PAH

content of engine oil increases with operating time, because the PAH formed

during combustion in petrol engines accumulates in the oil.

e) Lubricating oil is transformed by the high temperatures and stress of an engine's

operation. This results in oxidation, nitration, cracking of polymers and

decomposition of organ- metallic compounds

f) Other contaminants also accumulate in oil during use - fuel, antifreeze/coolant,

water, wear metals, metal oxides and combustion products.

g) It reduces or prevents air and light to reach at the life of bodies which are covered

by oil.

h) One litre of Used / Waste oil can ruin 1 million litre of fresh water and has the

ability to destroy both the pure and waste water drainage system

i) It affects the photosynthesis of plant.

j) It causes the oil toxic.

3.5 CONTAMINANT OF USED OIL

a) Some contaminants, such as chlorinated solvents, are picked up by the waste

oil during use

b) or during storage waiting for collection. However, not all chlorine found in

waste oil is

c) necessarily the result of contamination; small amounts (up to hundreds of

ppm) may have

d) come from additives in the original product. There are some other

contaminants which get

e) added to Waste Oils due to the operational conditions. They are:

Water

a) Fuel burns to CO2 and H2O. When an engine is cold, such generated water can

pass

b) through to the lube oil.

Fuel

Unburnt petrol / diesel passes through to the lube oil during engine start-ups.

Carbon

a) Forms as a result of incomplete combustion when an engine is warming up and it

passes

b) through to the lube oil.

Dust

Small particles pass into the engine through the air breather.

Metals

Due to normal component wear and tear.

Oxidation Products

a) Additive chemicals at elevated temperatures in the presence of oxygen can

oxidize forming

b) corrosive acids

3.6 RE-REFINING OF USED LUBRICATING OIL BY

VACUUM DISTILLATION

Dewatering of waste oil

The oil is de-watered in large settling tanks, wherein the heavier water settles to the

bottom of the tank and the light oil floats on top. The water at the bottom is drained off

and should normally be treated before disposal. However this does not remove the water

completely and small quantity still remains. Then this dewatering oil is subjected to

vacuum distillation to remove all contaminants present in it.

Vacuum Distillation

This is the core process for lubricating oil re-refining. In India, the general practice is to

refine waste oil in a vacuum process. The de-watered oil is heated in vacuum distillation

tower under vacuum. As the temperature in the distillation tower rise, the temperature of

various components waste oil increases. Temperature in the tower maintained in

descending order from top to bottom. The various components after reaching at their

respective boiling point, they tends to vaporize and start to liberated and rise as vapour to

be condensed in a condenser. The tower is filled with de-watered waste lubricating oil.

The capacity of the tower may be 6600litres. It takes about one hour to charge the tower

completely and for oil to pick up the sensible heat from the tower. As the temperature of

the dewatered oil rises, the ware present in the oil is removed first and at around 170°C-

180°C, gasoline and diesel is vapourised and released from the oil and from the tower. At

this time vacuum inside the tower ranges from 15 torr (.0197 atm) to 20 torr (.0263 atm).

After removal of diesel the pressure inside the tower is brought to less than one torr. This

can be done by using a vacuum pump. The lube oil is the main product and its distillation

starts around 270°C and continues upto 300°C- 320°C. Most of the lubricating oil distils

out during this process. Metals, dust, rust, soot are the bottom product which are drained

out for disposal. Total time taken for the process is about 7-8 hours.

DIAGRAM OF VACUUM DISTILLATION TOWER FOR REREFINING OF

USED LUBE OIL

3.7 ADVANTAGES OF RE-REFINING OF USED OIL

Economic Reasons

The most important advantage of Re-Refining is economic. Industries are using more and

more lubricants and this means more and more expenditure on lubricants. If the option of

Re-Refining is adopted by these industries a lot of expenditure on lubricants can be saved

and the saving can be as high as up to 50%.

Conservation of precious petroleum product

In India all lube oil is imported. If Used Oils generated in the country is processed and

lube base oil is recovered import bill can be substantially reduced. Therefore Re-Refining

is an import substitute. If the demand of imports of Lube Oil is reduced because of Re-

Refining the advantage of Re-Refining is saving of foreign exchange for the Country.

Like other advanced Countries in India Re-Refining of Used Oil should be made

mandatory.

Protection of Environment

Re-Refining of Used Oil can play a big role in reducing pollution. Reckless dumping of

Used Oil can cause damage to land and water and burning of Used Oil as fuel can pollute

air. Re-refining of used oil while saving the environment also creates wealth for the

generator of used oil.

Utilization of hazardous waste

Used oil is termed as hazardous. Lube oil does not wear out with use it only gets

contaminated with water, carbon and fuel etc. that means used oil when it is ready for

rejection can be re-used. Re-refining of used oil is the best mode of disposal of used oil.

Re-refining of the used oil is the most rational and lucrative solution for the problem of

disposal of hazardous waste. This is an outstanding example of converting waste into

wealth.

Lubricating oil market in India

As per an IIP study, 10,00,000 tonnes of lube oil was consumed by the Indian market in 2001. 

6,50,000 tonnes per year is engine crankcase oil.

Around 380 million dollars i.e. around Rs.17,290 million are spent in procuring base oil. 

Around 5,00,000 tonnes of used oil can be recycled producing 3,50,000 tonnes of refined base

oil. 

This results in a saving of 140 million dollars i.e. about Rs.6,370 millions in foreign exchange. 

The above observations are based on the assumption that base oil costs US$400 for every MT.

3.8 APPLICATION

a) Automotive

a. Engine oils

i. Petrol (Gasoline) engine oils

ii. Diesel engine oils

b. Automatic transmission fluid

c. Gearbox fluids

d. Brake fluids

e. Hydraulic fluids

b) Tractor (one lubricant for all systems)

a. Universal Tractor Transmission Oil – UTTO

b. Super Tractor Oil Universal – STOU – includes engine

c) Other motors

a. 2-stroke engine oils

d) Industrial

a. Hydraulic oils

b. Air compressor oils

c. Gas Compressor oils

d. Gear oils

e. Bearing and circulating system oils

f. Refrigerator compressor oils

g. Steam and gas turbine oils

e) Aviation

a. Gas turbine engine oils

b. Piston engine oils

f) Marine

a. Crosshead cylinder oils

b. Crosshead Crankcase oils

c. Trunk piston engine oils

d. Stern tube lubricant.

e.

CHAPTER 4

CONCLUSION

Thus this process of re-refining of used lubricating oil, using vacuum distillation process

can be adopted. This will reduce environment pollution and save our petroleum resources

and also would be well worth of it.

REFERENCE

1. M. Fuchs, The World Lubricants Market, 8th International Conference on

Industrial Tribology, Calcutta, 1997

2. IARC, Classification of Mineral oils According to their Carcinogenicity, Vol. 33,

1984.

3. T. Sullivan, “Forecast: New Price Leaders in Town,” Lube Report 5(27) (2005).

4. Chevron press release, April 8, 2005.

5. H. E. Henderson, “Gas-to-Liquids,” Canadian Chemical News September: 17–19

(2003).

6. www.lubereport.com/e_article000194571.cfm

7. T. Sullivan, “ExMo Rules the Base Oil Roost,” Lube Report 5(25) (2005).