Re-refining of UsedLubricatingOil

By

School of Chemical and Materials Engineering (SCME)

National University of Sciences and Technology (NUST)

June, 2013

refining of UsedLubricatingOil

Syed Waqas Haider

M. Aqib Shahzad

Muhammad Usman

School of Chemical and Materials Engineering (SCME)

National University of Sciences and Technology (NUST)

refining of UsedLubricatingOil

School of Chemical and Materials Engineering (SCME)

National University of Sciences and Technology (NUST)

1

Group members:

1. Syed Waqas Haider 2009-NUST-BE-Chem-27

2. M. Aqib Shahzad 2009-NUST-BE-Chem-12

3. Muhammad Usman 2009-NUST-BE-Chem-18

Supervisor:

Lecturer Umair Sikander

This work is submitted as a FYP report in partial fulfillment of the

requirement for the degree of

(BE in Chemical Engineering)

School of Chemical and Materials Engineering (SCME)

National University of Sciences and Technology (NUST), H-12

Islamabad, Pakistan

June, 2013

Certificate

This is to certify that work in this dissertation/report has been carried out by

Syed Waqas Haider, M. Aqib Shahzad and Muhammad Usman completed

under my supervision in school of chemical and materials engineering (SCME),

National University of Sciences and Technology (NUST), H-12, Islamabad,

Pakistan.

Supervisor: ______________

Lecture Umair Sikander

Chemical Engineering Department

School of Chemical and Material Engineering (SCME)

National University of Sciences and Technology (NUST), Islamabad

Submitted through:

HoD _______________________

Chemical Engineering

Principal/Dean ___________________

SCME

Dedication

We dedicate our project to our beloved Parents. Without their support we could

surely not be at this stage.

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Acknowledgments

We are greatly thankful to Almighty Allah WHO helped us at every

stage of the project. With the grace of Almighty Allah, we are able to

reach the completion of our project successfully. We would also like

to thank our beloved parents who also helped us at every time, we

wanted their help.

We would specially like to thank our project supervisor Mr. Umair

Sikander whose constant motivation, cooperation, guidance and help

resulted in the accomplishment of this project.

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Abstract

Lubricating oils keep machinery cleaner and allow the machinery to work

under severe operating conditions. However once used, they need special

attention as if they are disposed off without treatment, they cause serious

pollution problems.

The motivation of our project was to develop a method which is energy

economical i.e. uses less energy owing to increasing energy issues of Pakistan.

In this project we studied different existing processes and then formulated a

process which is more energy efficient. The processes before were mostly using

distillation in which temperatures up to 600 Co were required.

We found re-refining of waste lubricating oil by solvent extraction as one

of the potential techniques. Different solvents were tested with oil samples. In

solvent extraction, there were 3 components: the basic component, polar

addition and oil sample. Resulting mixtures were tested analytically using

Fourier Transform Infrared Spectroscopy (FTIR) as analytical technique. By

comparing the used and treated samples, we found the best solvent, one which

is most efficient. All this research was followed by initial material balance and

cost analysis.

The main tasks which we have done in our project include:

Experimental

Work

Process

Development

Block Flow

Diagram

Material Balance Designing of

Extractor

Cost Estimation

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Table of Contents

1 Introduction 13

1.1 Characteristics of a Lubricant 14

1.2 Lubricating oil Purpose 15

1.2.1 Keep moving parts apart 15

1.2.2 Reduce friction 15

1.2.3 Transfer heat 17

1.2.4 Carry away contaminants and debris 17

1.2.5 Transmit power 17

1.2.6 Protect against wear 17

1.2.7 Prevent corrosion 17

1.2.8 Seal for gases 17

1.3 Properties of Lubricants 17

1.3.1 Viscosity 18

1.3.2 Viscosity Index 18

1.3.3 Cloud Point and Pour Point 18

1.3.4 Flash Point and Fire Point 19

1.3.5 Neutralization Number 19

1.3.6 Water Content 19

1.3.7 Demulsibility 20

1.3.8 Load Carrying Ability 20

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1.3.9 Air-Handling Ability 20

1.3.10 Corrosion Control 20

1.3.11 Acid Number 20

1.4 Additives in lubricating oils 20

1.4.1 Friction modifiers 21

1.4.2 Anti-wear additives 21

1.4.3 Extreme pressure (EP) additives 22

1.4.4 Rust and corrosion inhibitors 22

1.4.5 Anti-oxidants 23

1.4.6 Detergents 23

1.4.7 Dispersants 23

1.4.8 Pour point depressants 24

1.4.9 Viscosity index improvers 24

1.4.10 Anti-foaming agents 24

1.5 Used Oil and Its Composition 24

1.5.1 Water 25

1.5.2 Soot and carbon 25

1.5.3 Lead 25

1.5.4 Fuel 25

1.5.5 Road dust 25

1.5.6 Wear metals 25

1.5.7 Oxidation products 26

1.6 AIMS & GOALS of PROJECT 26

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2 Background 27

2.1 Pakistan needs Clean Oil Technology 27

2.2 General Treatment Methods 29

2.3 Drawbacks of Existing Processes 31

2.3.1 Acid/Clay Treatment 31

2.3.2 Vacuum Distillation 31

3 ExperimentalWorks 32

3.1 Techniques Used 32

3.1.1 Liquid-Liquid Extraction 32

3.1.1.1 Advantages of LLE 33

3.1.2 Fourier Transform Infrared (FT-IR) spectrometry 34

3.2 The Sample Analysis Process 35

3.3 SPECTROSCOPY - Study of spectral information 36

3.3.1 Parameters associated with electromagnetic radiation 37

3.4 IR Spectra 41

3.5 Experimental Scheme 42

3.7 Experiments Performed 45

3.6 Experimental Results 47

3.7.1 Spectrogram of fresh un-used motor oil 47

3.7.2 Spectrogram of used motor oil from Bike 48

3.7.3 Spectrogram of used motor oil 48

3.7.4 Spectrogram of treated oil with CCl4 in 1:1 49

3.7.5 Treated oil with benzene in 1:1 50

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3.7.6 Treated oil with benzene in 2:1 50

3.7.7 Treated oil using brine as a polar addition and CCl4 in 2:1 (oil to

solvent) ratio 51

3.7.8 Two spectrograms comparison 51

3.7.9 Experimental Objective 52

4 Process Development

4.1 Process Description 53

4.1.1 Dehydration 53

4.1.2 Solvent Extraction 54

4.1.3 Solvent Stripping 54

4.1.4 Ammonium Sulphate Treatment 55

4.2 Block Flow Diagram 56

5 Material Balance 59

5.1 McCabe Thiele Diagram 57

5.2 Theoretical Plates 60

5.3 Extractor Sizing 61

5.3.1 The column diameter 63

5.3.2 Column Height 63

6 Costing& Sizing

6.1 THE FACTORIAL METHOD OF COST ESTIMATION 65

6.1.1 Procedure 65

6.2 Sizing of Major Equipments 69

6.2.1 Dehydration Tank 69

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6.2.2 Stripper 69

6.2.3 Condenser 69

6.2.4 Ammonium Sulfate tank 70

6.3 Equipment Cost 70

6.3.1 Dehydration tank 71

6.3.2 Extractor 71

6.3.3 Stripper 71

6.3.4 Condenser 71

6.3.5 Ammonium Sulfate tank 71

6.3.6 Total purchase equipment cost 72

6.4 Operating Cost 72

7 Industrial Application 74

References 75

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List of Figures

Figure 1: Sample analysis process

Figure 2: Spectroscopy

Figure 3: Bond vibration

Figure 4: Spectrogram: absorption mode

Figure 5: Spectrogram: transmission mode

Figure 6: Bond’s peak on spectrogram

Figure 7: IR absorption range

Figure 8: Extraction in lab

Figure 9: FTIR of fresh motor oil

Figure 10: FTIR of used bike oil

Figure 11: FTIR of used motor oil from market

Figure 12: FTIR of treated oil with CCl4 in 1:1

Figure 13: FTIR of treated oil with benzenein 1:1

Figure 14: FTIR of treated oil with benzene 2:1

Figure 15: Treated oil using Brine as a polar addition

Figure 16: Two spectrogram comparison

Figure 17: Extraction using benzene in lab

Figure 18: Block Flow Diagram

Figure 19: McCabe Thiele Diagram

Figure 20: heat transfer area vs. exchanger’s cost

Figure 21: Vessel height vs. equipment cost

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List of Tables

Table 1 Experimental Scheme 1

Table 2 Experimental Scheme 2

Table 3Experimental Scheme 3

Table4 Experimental Scheme 4

Table5 Experiments Performed

Table 6 Operating Line Data

Table 7 Equilibrium Line Data

Table 8 Column Sizing Data

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Chapter # 1

Introduction

Used automotive oil is generated from the transport sector when oil loses its

effectiveness during operation because contamination from the combustion chamber, metallic

particles together with water, varnish and gums result in the wear and tear of the engine parts.

Asphaltic compounds additives, light hydrocarbons, resinous material, mono and

polyaromatic compounds, carbon black and used base oil made it toxic chemicals mix urban

areas at filling stations and motor repair shops.

Used oil creates environmental pollution if not disposed properly; there is a possibility that

substances that it may contain enter natural cycles through the food chain via water, soil and

air. In this way, used oil pose risk to human health and impedes the growth of plants and their

ability to take up water as sometimes used oil contained hydrocarbons, heavy metals,

polyclorinatedbiphnyls (PCBs) and other halogenated compounds (El-Fadel and Khouy

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(2001), detergents and lubrication additives. Used lubricating oil must be disposed of

properly, if burnt as a low grade fuel, harmful metals and other pollutants may be released

into air (Blundell, 1998). In 1995 it was estimated that less than 45% of used oil was

collected worldwide and the remaining 55% was either misused (Environmental Oil Ltd.

2000) or improperly disposed by the end user severely increasing the problem of waste

discharged into the environment.

In Pakistan, until now, no used oil management systems are available and the level of public

awareness is very low in respect of environmental impacts. According to recent studies about

274,000 tons of used oil generated each year from vehicles, is being improperly disposed in

Pakistan.

In this modern age, the purification of used oil into parent base oil is a suitable way for

energy conservation and to avoid pollution. Used oil re-refining takes 50-85% less energy to

produce the same volume than by refining virgin crude (API,1997). Automotive lubricants

are generally considered to be of higher quality than industrial oils for recycling to base lube

oil. It is an important resource and a valuable petroleum base product. The high price of crude

oil and the objective of saving valuable foreign exchange have resulted in efforts to

regenerate used lube oil into clean lubricants.

1.1Characteristics of a Lubricant

A good lubricant possesses the following characteristics:

High boiling point

Low freezing point

High viscosity index

Thermal stability

Hydraulic Stability

Demulsibility

Corrosion prevention

High resistance to oxidation

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1.2Lubricating oil Purpose

Lubricants perform the following key functions.

Keep 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

1.2.1Keep 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.

1.2.2 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

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insufficient bulk lubricant present for hydrodynamic lubrication, e.g. protecting the valve

train in a car engine at start-up.

1.2.3 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 bearings. 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.

1.2.4 Carry away contaminants and debris

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

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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.

1.2.5 Transmit power

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.

1.2.6 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.

1.2.7 Prevent corrosion

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

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

1.2.8 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.

1.3 Properties of Lubricants:

There are some properties of lubricants/lubricating oil

Viscosity

Viscosity index

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Cloud point and pour point

Flash and fire point

Neutralisation number

Water content

Load carrying ability

Air handling ability

Corrosion control

Acid number

1.3.1 VISCOSITY

The most important physical property of a lubricant is its viscosity. Viscosity, which may be

defined as a fluid’s resistance to flow, is the characteristic most frequently stipulated by

equipment manufacturers. When making lubricant recommendations. The selection of proper

lubricant viscosity is often a compromise between selecting one high enough to prevent metal

to metal (wear) contact, and one low enough to allow Sufficient heat dissipation.

1.3.2 Viscosity Index

The Viscosity Index, commonly designated VI, is an arbitrary numbering scale that indicates

the changes in oil viscosity with changes in temperature. Viscosity index can be classified as

follows:

Low VI - below 35

Medium VI - 35 to 80

High VI - 80 to 110

Very High VI - 110 to125

Super VI - 125 to 160

Super High VI - above 160 to 200

1.3.3 CLOUD POINT AND POUR POINT

Since petroleum stock consists of a mixture of molecular components, lubricants do not

exhibit sharp freezing points. Rather, as a lubricant is cooled, certain components such as

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waxes will begin to precipitate out and become evident in the liquid as a cloud. The

temperature at which this occurs is called the cloud point of the lubricant. If the product is

further cooled, a point will be reached at which the lubricant will no longer flow or be

efficiently pumped. The temperature at which this occurs is termed the pour point of the

lubricant.

1.3.4 FLASH POINT AND FIRE POINT

As a lubricant is heated, lighter components begin to vaporize.The temperature at which

sufficient vapor concentration exists above the surface of the lubricant so that ignitionwith a

test flame is possible is called the flash point of the product. Flash point is useful for both

product storagerequirements and for the detection of contamination of one product with

another. The fire point of a lubricantis that temperature at which sufficient vapors are present

above the surface of the lubricant to sustain combustionupon ignition. This parameter is

useful for storage and safety considerations.

1.3.5 NEUTRALIZATION NUMBER.

As petroleum products are subjected to elevated temperatures, theprocess of oxidation

occurs. Oxidation leads to the formation of organic acids in the lubricant. This increase

inacidity reduces the water-separating ability of certain oils, and may also prove corrosive to

certain alloys. Theneutralization number measures the amount of acidity present in the

lubricant. It is quantitatively defined as theamount of potassium hydroxide (KOH) required

neutralizing the acid present in one gram of sample. This quantityis also referred to as the

Total Acid Number (TAN).

1.3.6 WATER CONTENT

Common sources of water include lube oil cooler leaks, condensation, steam turbine gland

seal leaks, and diesel engine piston blow-by and jacket water leaks. The acceleration of

system corrosion by water contamination cannot beoveremphasized. In addition, excessive

water contamination increases the viscosity and decreases the fluid film strength of an oil

.

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1.3.7 DEMULSIBILITY

Demulsibility refers to a lubricant’s ability to readily separate from water. Oils

used in force-feed lubrication systems should possess good water separatability to prevent

emulsification.

1.3.8 LOAD CARRYING ABILITY

The ability of a lubricant to maintain an effective lubricating film under high loads or

pressures is a measure of its load carrying or extreme pressure (EP) characteristics.

1.3.9 AIR-HANDLING ABILITY

The quality of a lubricant’s basestock and the use of certain additives can define its air-

handling abilities. We want a lubricant to release entrained air rapidly and to suppress the

formation of foam. Air handling is nearly impossible to interpret from ordinary oil analysis.

1.3.10 CORROSION CONTROL

Corrosion control is a fundamental lubricant formulation objective. There are many additives

used to neutralize corrosive agents or form protective barriers on sensitive machine surfaces.

These are sacrificial additives that lose their effectiveness over time. Nonetheless, no

conventional used oil analysis test, other than the base number, reports the residual

effectiveness of the corrosion-protecting qualities of an in-service lubricant.

1.3.11 ACID NUMBER

The acid number for an oil sample is indicative of the age of the oil and can be used to

determine when the oil must be changed.

1.4 Additives in lubricating oils

Additives are substances formulated for improvement of the anti-friction, chemical and physical

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properties of base oils (mineral, synthetic, vegetable or animal), which results in enhancing the

lubricant performance and extending the equipment life.

Combination of different additives and their quantities are determined by the lubricant type (Engine

oils, Gear oils, Hydraulic oils, cutting fluids, Way lubricants, compressor oils etc.) and the specific

operating conditions (temperature, loads, machine parts materials, environment).

Amount of additives may reach 30%.

I. Friction modifiers

II. Anti-wear additives

III. Extreme pressure (EP) additives

IV. Rust and corrosion inhibitors

V. Anti-oxidants

VI. Detergents

VII. Dispersants

VIII. Pour point depressants

IX. Viscosity index improvers

X. Anti-foaming agents

1.4.1 Friction modifiers

Friction modifiers reduce coefficient of friction, resulting in less fuel consumption.

Crystal structure of most of friction modifiers consists of molecular platelets (layers), which

may easily slide over each other.The following Solid lubricants are used as friction

modifiers:

Graphite

Molybdenum disulfide

Boron nitride (BN)

Tungsten disulfide (WS2)

Polytetrafluoroethylene (PTFE)

1.4.2 Anti-wear additives

Anti-wear additives prevent direct metal-to-metal contact between the machine parts when

the oil film is broken down. Use of anti-wear additives results in longer machine life due to

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higher wear and score resistance of the components. The mechanism of anti-wear additives:

the additive reacts with the metal on the part surface and forms a film, which may slide over

the friction surface.

The following materials are used as anti-wear additives:

Zinc dithiophosphate (ZDP)

Zinc dialkyldithiophosphate (ZDDP)

Tricresylphosphate (TCP)

1.4.3 Extreme pressure (EP) additives

Extreme pressure (EP) additives prevent seizure conditions caused by direct metal-to-metal

contact between the parts under high loads. The mechanism of EP additives is similar to that

of anti-wear additive: the additive substance form a coating on the part surface. This coating

protects the part surface from a direct contact with other part, decreasing wear and scoring.

The following materials are used as extra pressure (EP) additives:

Chlorinated paraffins

Sulphurized fats

Esters

Zinc dialkyl dithiophosphate (ZDDP)

Molybdenum disulfide

1.4.4 Rust and corrosion inhibitors

Rust and Corrosion inhibitors, which form a barrier film on the substrate surface reducing

the corrosion rate. The inhibitors also absorb on the metal surface forming a film protecting

the part from the attack of oxygen, water and other chemically active substances.

The following materials are used as rust and corrosion inhibitors:

Alkaline compounds;

Organic acids;

Esters;

Amino-acid derivatives

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1.4.5 Anti-oxidants

Mineral oils react with oxygen of air forming organic acids. The oxidation reaction products

cause increase of the oil viscosity, formation of sludge and varnish, corrosion of metallic

parts and foaming. Anti-oxidants inhibit the oxidation process of oils.

Most of lubricants contain anti-oxidants.

The following materials are used as anti-oxidants

Zinc dithiophosphate (ZDP)

Alkyl sulfides;

Aromatic sulfides

Aromatic amines

Hindered phenols

1.4.6 Detergents

Detergents neutralize strong acids present in the lubricant (for example sulfuric and nitric

acid produced in internal combustion engines as a result of combustion process) and remove

the neutralization products from the metal surface. Detergents also form a film on the part

surface preventing high temperature deposition of sludge and varnish.

Detergents are commonly added to Engine oils.

Phenolates, sulphonates and phosphonates of alkaline and alkaline-earth elements, such as

calcium (Ca), magnesium (Mg), sodium (Na) or Ba (barium), are used as detergents in

lubricants.

1.4.7 Dispersants

Dispersants keep the foreign particles present in a lubricant in a dispersed form (finely

divided and uniformly dispersed throughout the oil)The foreign particles are sludge and

varnish, dirt, products of oxidation, water etc.Long chain hydrocarbons succinimides, such as

polyisobutylenesuccinimides are used as dispersants in lubricants.

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1.4.8 Pour point depressants

Pour point is the lowest temperature, at which the oil may flow.Wax crystals formed in

mineral oils at low temperatures reduce their fluidity.Pour point depressant inhibit formation

and agglomeration of wax particles keeping the lubricant fluid at low temperatures.Co-

polymers of polyalkylmethacrylates are used as pour point depressant in lubricants.

1.4.9 Viscosity index improvers

Viscosity of oils sharply decreases at high temperatures. Low viscosity causes decrease of the

oil lubrication ability. Viscosity index improvers keep the viscosity at acceptable levels,

which provide stable oil film even at increased temperatures. Viscosity improvers are widely

used in multigrade oils, viscosity of which is specified at both high and low

temperature.Acrylate polymers are used as viscosity index improvers in lubricants.

1.4.10 Anti-foaming agents

Agitation and aeration of a lubricating oil occurring at certain applications (Engine oils, Gear

oils, Compressor oils) may result in formation of air bubbles in the oil - foaming. Foaming

not only enhances oil oxidation but also decreases lubrication effect causing oil starvation.

Dimethylsilicones (dimethylsiloxanes) is commonly used as anti-foaming agent in lubricants.

1.5 USED OIL AND ITS COMPOSITION

Lubricating oil becomes unfit for further use for two main reasons: accumulation of

contaminants in the oil and chemical changes in the oil. The main contaminants are listed

below.

Combustion products

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1.5.1 Water

Fuel burns to CO2 and H2O. For every litre of fuel burnt, a litre ofwater is created. This

normally passes out through the exhaust whenthe engine is hot, but when cold it can run

down and collect in the oil.This leads to sludge formation and rust.

1.5.2 Soot and carbon.

These make the oil go black. They form as the result of incompletecombustion, especially

during warm-up with a rich mixture.

1.5.3 Lead

Tetraethyl lead, which used to be used as an anti-knock agent in petrol, passes into the oil. A

typical used engine oil may have contained up to2% lead, but today any lead comes from

bearing wear and is likely tobe in the 2 - 12 ppm range.

1.5.4 Fuel

Unburnt gasoline or diesel can pass into the lubricant, again especiallyduring start-up.

Abrasives

1.5.5 Road dust

This passes into the engine through the air-cleaner. Composed ofsmall particles of silicates.

1.5.6 Wear metals

Iron, copper and aluminium released due to normal engine wear.

Chemical products

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1.5.7 Oxidation products

Some of the oil molecules, at elevated temperatures, will oxidise to form complex and

corrosive organic acids

1.6 AIMS & GOALS of PROJECT

To formulate a new method for re-refining of used lubricating oil which :

More energy efficient

Less expensive

Less complicated

Eliminating environmental pollution hazards

Previously the methods being used were mostly using distillation as separation technique

which is more energy consuming while we try to exclude it.

27

Chapter # 2

Background

2.1 Pakistan needs clean oil technology:

The lubricants base oil so produced by the refineries cannot be used unless their physical and

chemical properties suiting a particular type of machine are compounded. The light and

heavy base oils are mixed in suitable proportions to adjust their thickness to engine

requirements. Further, during use to control lubricants foaming, rust prevention, to act as

detergent, non-freezing in cold climate, anti-oxidant and thermally stable product is needed

for which some organic metallic additives have to be added so that the lubricant can reduce

friction and heat in the engine, act as a coolant and sealant liquid. These additives are called

poly-chloro-bi-phenyls (PCBs) and poly-chloro-ter-phenyls (PTBs) etc.

These additives have been found to be environmentally hazardous and can cause cancer of

lever, kidney and suffocation, deformities in newly born children and other ailments if

consumed in high dosages. The regular contact of used lubricants on human skin or entry of

its additives in the food chain through the burning of used lubricants sludge in brick kilns as a

source of heat, whereby the ashes are washed down to the underground water table in rainy

season can cause recycling of PCBs in agricultural products.

These additives are therefore to be either thermally destroyed or safely recycled so that they

do not enter the air, water or ground to find their ultimate way into food chain or water. These

additives are very stable and only high incinerator temperatures might destroy them. Their

safe disposal is necessary in compliance with the “National Environmental Quality Standards

(NEQS). Though the Pakistan Environmental Protection Law has been enacted over two

decades ago, specific attention has not been paid to spread of this deadly poison. An

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awareness campaign is necessary to inform the public about the harmful effects of such

compounds.

The main bulk of lubricants base oil growth of uncertain consumption manufactured by

National Oil Refinery Ltd and the other four refineries of Pakistan and more unfortunately

waste oil; collected is catered to oil reclamation industry, which has hefty growth in Pakistan

in the form of both legal and illegal plants and smuggling throughout western border belts.

The illegal growth of the make shift plants in various congested areas of Karachi and other

parts of Pakistan is menacingly spreading inside houses, hidden factories, and god owns,

walled and green bushy areas. The same is the case of collectors of waste used lubricating

oils and suppliers of waste oil who concentrate in streets by-lines and motor oil depots on

main roads. The products of various legal/illegal plants are sub-standard, stink and are of dark

colour and the road side sale depots sell these duly packed and/or loose in popular brand

containers; usually purchased by illiterate transporters and even by ordinary consumers who

need cheaper oils and are in total darkness of the hazardous and devastating effects on the

environment and machinery. The environmental disaster created by these domesticated

industries can be well imagined as our masses are oblivious of toxic generated and users

machine wear.

The dangerous sources attributable to global warming and adverse effects on life is sub-

standard supply of petroleum products viz. petrol, diesel and kerosene containing sulphur

contents ranging from 1000-1800 ppm of sulphur and other greenhouse gases in enormous

quantities . When these petroleum products are used their exhaust gases contain these

greenhouse gases in huge quantities causing global warming-climate change and subsequent

disasters caused by global warming-climate change. Most parts of the world including India

have adopted EUROIV standards but so far GOP has totally neglected this heinous crime of

not adapting to upgrade its petroleum products.

The other dangerous sources attributable to global warming and adverse effects on life in the

lubricant sector alone in Pakistan include “Lubricants Sludge and Residues’, “Spurious oils”,

“Carbon oil”, “Sludge oil”, “Rubber Oil”, “Polymer Oils”, and “Wax Oils”. The havocs

caused by the use of above mentioned oils are immense and it is high time for the GOP to

29

take care of these genuine hazardous issues.

It is alarming to note that in Pakistan all the “Reclamation/recycling plants for lubricating oils

are based on “Dirty Oil Technology”.

In Pakistan, the used/waste lubricating oil is collected from the workshops and places where

oil is changed and is sold to the legal/illegal recycling plants, where “Dirty Oil Technology-

Acid Clay Technology” is used for recycling of dirty/waste lubricating oil.

2.2 General Treatment Methods:

Commonly used oil treatments include primarily re-processing, reclamation and regeneration.

The insoluble contaminants and oxidation products can be removed by heating, settling,

filtering, dehydrating or centrifuging to separate solids and water from the used oils which is

then used as fuel. Where the re-generation is a process to produce base oil, pre-distillation,

treatment with acid, solvent extraction, contact with activated clay and hydro-treating is

required (known as re-generation). It results in the recovery of base oil with maximum

commercial value. Waste-oil management thus provides a suitable way of promoting energy

conservation and environmental sustainability by treatment and reuse of oils. Production of

re-refined base lube also uses a combination of physical, chemical, thermal and distillation

processes, with the addition of hydro treating, to separate water and suspended solids and

other contaminants from the used oil so that the product can be used interchangeably with

virgin lube oil in lube oil applications. Re-refined base lube is considered to be closed-loop

recycled. So far the following major regeneration methods have been in common use:

• Acid /clay treatment

• Vacuum distillation / clay treatment

• Vacuum distillation / catalytic hydro treatment

• Solvent extraction and clay treatment

Wrong Treatment Technology means Pollution:

Worldwide, where the governments care for avoidance of air pollution, water pollution and

pollution of their food chain; The waste/ used lubricating oil from the vehicles and machinery

30

is collected in cans and is sent to the recycling plants where this used/waste lubricating oil is

recycled to obtain clean lubricating oil for further use by the use of “Clean Oil Technology”.

In Pakistan, the used/waste lubricating oil is collected from the workshops and places where

oil is changed and is sold to the legal/illegal recycling plants, where “Dirty Oil Technology-

Acid Clay Technology” is used for recycling of dirty/waste lubricating oil.

The used/waste oil collected in these plants are filled into a large crucibles 98% concentrated

sulphuric acid nine percent by volume of the waste/dirty oil quantity by volume is added;

sodium carbonate (washing soda) is added into the crucible and 7-8% of bleaching earth is

added and then heated to 130-135 degrees centigrade.

Then polychlorobiphenyles (PCBs) and/ or Polychloroterphenyles (PTBs) is added to obtain

lubricating oil. The so obtained lubricating oil contains PCB/PTB that is imperative to be

removed. There is no provision for the removal of these hazardous Compounds from the

lubricating oil obtained by such a process. Furthermore, the so Obtained residue/sludge which

contains entire concentrated acid PCBs/PTBs without any neutralization process is sold to

brick kilns. An approximate of 2.1 million tons/per year of such hazardous residue/sludge

obtained during the process of obtaining lubricating oil from lub.oil base oils and dirty/waste

oil.

These residues are mixed with saw dust/husk and are used in the brick kilns as fuel.

The maximum temperature of brick kilns is between 600-800 degrees centigrade which is not

sufficient enough to destroy the hazardous effect of the ashes so obtained; as a matter of fact

the harmful effects can only be removed/destroyed in incinerators where the temperatures are

in the range of 1500-1600 degrees centigrade.

The most deadly ashes obtained from the brick kilns pave their way through rain water and

water ways into the ground; polluting almost all fresh water and subsequently enter into the

food chain and entire agricultural products. Almost the entire fresh water is polluted and is

unsuitable for living beings consumption; it pollutes air and is responsible for spread of

diseases like cancer of liver, lungs, stomach, and several diseases of stomach, diarrhea,

vomiting, difficulties of breathing, allergy, skin diseases etc.

A senior steward (Secretary), holder of a doctorate degree of the Ministry of Petroleum and

31

Natural Resources issued a S.R.O-1291 (1)/99 dated November 11, 1999 while taking

cognizance of this deadly spread of the diseases, pollution of air and water chain by issuance

of directives for “Setting up of vacuum distillation units in all the plants approved or

registered with the Ministry of Petroleum and Natural Resources.

In 1999 there were some seventy plants registered/approved by the Ministry whereas today

there is a mushroom growth of such deadly plants.

It is regretful to note that the able steward of the Ministry is ignorant “Non-Acid High

Vacuum Distillation plant” which is the only way to eliminate PCBs and PTBs and the

language of the S,R.O. is so misleading and wrongly drafted that the plants procured a toy

like worthless unit, totally unsuitable for elimination of PCBs and PTBs; but the ignorant

steward to the GOP are happy to claim that they have taken corrective steps but the fact

remains that there is no stoppage to the spread of deadly diseases, air pollution and severe

pollution of fresh water.

2.3 Drawbacks of Existing Processes:

Most existing processes have some drawbacks associated to them which include

environmental unfriendliness, economically unfeasible, energy consumption.

2.3.1 Acid /clay treatment

Most existing reclaiming plants for re-refining of oil use sulphuric acid to coagulate

as an acid sludge the ash and polar components in used oil. \this followed by treatment with

alkaline solutions to neutralize the acid, water washing, active clay decolorizing, stripping,

and filtration yields a lube stock suited to reuse as a low grade motor oil or as a grease base.

The poor yield of re-refined oil and the environmental problems of disposal of acid sludge

and clay make this reclaiming process a marginal operation at best.

2.3.2 Vacuum Distillation:

Work has been done on hydro treating of the distilled oil to lube oil stock. This

process leaves a high ash residue, and serious problems in fouling of heat exchanger/

condenser and fractionation equipment have been encountered. The heavy oil containing the

ash remains to be disposed of by a satisfactory manner, not disclosed.

32

Chapter # 3

Experimental Work

Re-refining of used lubricating oil is one of the potential techniques. The advantages of

solvent extraction are high lightened because of economics and environmental pint of view.

We wanted to devise a process that should be environmentally safe keeping the process

within economic constraints.

Through literature review, we selected some solvents that could be used for solvent

extraction with used oil samples. We tried different solvents throughout our project and

results of all such experiments will be discussed later in this thesis.

3.1 Techniques Used:

3.1.1 Liquid–liquid extraction:

Liquid–liquid extraction, also known as solvent extraction and partitioning, is a

method to separate compounds based on their relative solubilities in two

different immiscible liquids, usually water and an organic solvent. It is an extraction of a

substance from one liquid into another liquid phase. Liquid–liquid extraction is a basic

technique in chemical laboratories, where it is performed using a separating funnel.

It is a separation technology that is based on the distribution of one more components

between two immiscible or almost immiscible liquids. Generally, one of the liquid phases is

water and the other an organic solvent .however, there are other well-known systems where

both phases are organic or organic mixtures.

Liquid extraction also known as solvent extraction is especially

processing of large capacities for this reason this operation is frequently used in the oil

industry.

Throughout from 100,000 m

reasonable size .although energy consumption

negligible the attached steps for the recovery of solvent require more or less energy

depending on the nature of the components and the difficulty of separation.

Often not only the extract phase but also ra

washing distillation or another follow up treatment.

The complete extraction process with solvent regenerat

needs a quite complex plant with the corresponding investment cost.

For the selection of suitable so

selectivity but also the ease of handling and regeneration the solubility in the raffinate the

product cost etc.

3.1.1.1 Advantages of liquid liquid extraction

Very large capacities

Are possible with minimum of energy consumption(for example separation of paraffins are

aromatics in the oil industry)

Liquid extraction also known as solvent extraction is especially suitable for the

processing of large capacities for this reason this operation is frequently used in the oil

Throughout from 100,000 m3/h or an even higher can be treated with extractors of

although energy consumption for the normal extraction process itself is most

negligible the attached steps for the recovery of solvent require more or less energy

depending on the nature of the components and the difficulty of separation.

Often not only the extract phase but also raffinate phase has to be processed by

r follow up treatment.

The complete extraction process with solvent regeneration and raffinate treatment

ds a quite complex plant with the corresponding investment cost.

n of suitable solvent one has to consider not only the extraction

selectivity but also the ease of handling and regeneration the solubility in the raffinate the

Advantages of liquid liquid extraction

possible with minimum of energy consumption(for example separation of paraffins are

33

suitable for the

processing of large capacities for this reason this operation is frequently used in the oil

/h or an even higher can be treated with extractors of

for the normal extraction process itself is most

negligible the attached steps for the recovery of solvent require more or less energy

ffinate phase has to be processed by

ion and raffinate treatment

vent one has to consider not only the extraction

selectivity but also the ease of handling and regeneration the solubility in the raffinate the

possible with minimum of energy consumption(for example separation of paraffins are

34

Selectivity when other standard separation methods(such as rectification)fail or require

expensive equipments or energy cost(example production of water free pyridine)

Heat sensitive products are processed at amibient or moderate temperature(example vitamin

production)

Separation of small contents of high boiling impurities,mostly is aqueous solution .in the

normal thermalseparation techniques,the complete water content has to be withdrawn by a

very energy intensive evaporation processs (example elimination of phenol from aqueous

waste)

3.1.2 Fourier Transform Infrared (FT-IR) spectrometry:

FTIRwas developed in order to overcome the limitations encountered with dispersive

instruments. The main difficulty was the slow scanning process. A method for measuring all

of the infrared frequencies simultaneously, rather than individually, was needed. A solution

was developed which employed a very simple optical device called an interferometer. The

interferometer produces a unique type of signal which has all of the infrared frequencies

“encoded” into it. The signal can be measured very quickly, usually on the order of one

second or so. Thus, the time element per sample is reduced to a matter of a few seconds

rather than several minutes.

Because the analyst requires a frequency spectrum (a plot of the intensity at each

individual frequency) in order to make identification, the measured interferogram signal

cannot be interpreted directly. A means of “decoding” the individual frequencies is required.

This can be accomplished via a well-known mathematical technique called the Fourier

transformation. This transformation is performed by the computer which then presents the

user with the desired spectral information for analysis.

Infrared spectroscopy

Ithas been a workhorse technique for materials analysis in the laboratory for over

seventy years. An infrared spectrum represents a fingerprint of a sample with absorption

peaks which correspond to the frequencies of vibrations between the bonds of the atoms

making up the material.

35

Because each different material is a unique combination of atoms, no two compounds

produce the exact same infrared spectrum. Therefore, infrared spectroscopy can result in a

positive identification (qualitative analysis) of every different kind of material. In addition,

the size of the peaks in the spectrum is a direct indication of the amount of material present.

With modern software algorithms, infrared is an excellent tool for quantitative analysis.

Figure 1: Sample analysis process

3.2 The Sample Analysis Process:

The normal instrumental process is as follows:

1. The Source: Infrared energy is emitted from a glowing black-body source. This beam

passes through an aperture which controls the amount of energy presented to the sample (and,

ultimately, to the detector).

2. The Interferometer: The beam enters the interferometer where the “spectral encoding”

takes place. The resulting interferogram signal then exits the interferometer.

36

3. The Sample: The beam enters the sample compartment where it is transmitted through or

reflected off of the surface of the sample, depending on the type of analysis being

accomplished. This is where specific frequencies of energy, which are uniquely characteristic

of the sample, are absorbed.

4. The Detector: The beam finally passes to the detector for final measurement. The detectors

used are specially designed to measure the special interferogram signal.

5. The Computer: The measured signal is digitized and sent to the computer where the

Fourier transformation takes place. The final infrared spectrum is then presented to the user

for interpretation and any further manipulation.

Because there needs to be a relative scale for the absorption intensity, a background

spectrum must also be measured. This is normally a measurement with no sample in the

beam. This can be compared to the measurement with the sample in the beam to determine

the “per cent transmittance.”

This technique results in a spectrum which has all of the instrumental characteristics

removed.

Thus, all spectral features which are present are strictly due to the sample. A single

background measurement can be used for many sample measurements because this spectrum

is characteristic of the instrument itself.

3.3 SPECTROSCOPY - Study of Spectral Information:

37

Figure 2: Spectroscopy

Upon irradiation with infrared light, certain bonds respond by vibrating faster. This response

can be detected and translated into a visual representation called a spectrum.

Once a spectrum is obtained, the main challenge is to the information it contains in

abstract, or hidden form This requires the recognition of certain patterns, the association of

these patterns with physical parameters, and the interpretation of these patterns in terms of

meaningful and logical explanations.

Most organic spectroscopy uses electromagnetic energy, or radiation, as the physical

stimulus.

Electromagnetic energy (such as visible light) has no detectable mass component. In

other words, it can be referred to as “pure energy.”

Other types of radiation such as alpha rays, which consist of helium nuclei, have a

detectable mass component and therefore cannot be categorized as electromagnetic energy.

3.3.1 Parameters Associated With Electromagnetic Radiation:

The important parameters associated with electromagnetic radiation are:

Energy (E): Energy is directly proportional to frequency, and inversely proportional to

wavelength, as indicated by the equation below.

• Frequency (μ)

• Wavelength (λ)

E = hμ

38

Infrared radiation is largely thermal energy. It induces stronger molecular vibrations in

covalent bonds, which can be viewed as springs holding together two masses, or atoms.

Figure 3: Bond vibration

The IR spectrum is basically a plot of transmitted (or absorbed) frequencies vs. intensity of

the transmission (or absorption). Frequencies appear in the x-axis in units of inverse

centimetres (wave numbers), and intensities are plotted on the y-axis in percentage units.

39

Figure 4: Spectrogram: absorption mode

Figure 5: Spectrogram: transmission mode

40

IR bands can be classified as strong (s), medium (m), or weak (w), depending on their

relative intensities in the infrared spectrum. A strong band covers most of the y-axis. A

medium band falls to about half of the y-axis, and a weak band falls to about one third or less

of the y-axis.

Figure 6: Bond’s peak on spectrogram

Not all covalent bonds display bands in the IR spectrum. Only polar bonds do so. These are

referred to as IR active. The intensity of the bands depends on the magnitude of the dipole

moment associated with the bond in question:

• Strongly polar bonds such as carbonyl groups (C=O) produce strong bands.

• Medium polarity bonds and asymmetric bonds produce medium bands.

• Weakly polar bond and symmetric bonds produce weak or non-observable bands.

41

3.4 IR Spectra:

• IR is most useful in providing information about the presence or absence of specific

functional groups.

• IR can provide a molecular fingerprint that can be used when comparing samples. If two

pure samples display the same IR spectrum it can be argued that they are the same

compound.

• IR does not provide detailed information or proof of molecular formula or structure. It

provides information on molecular fragments, specifically functional groups.

• Therefore it is very limited in scope, and must be used in conjunction with other techniques

to provide a more complete picture of the molecular structure.

IR Absorption Range

The typical IR absorption range for covalent bonds is 600 - 4000 cm-1. The graph shows the

regions of the spectrum where the following types of bonds normally absorb. For example a

sharp band around 2200-2400 cm-1 would indicate the possible presence of a C-N or a C-C

triple bond.

Figure 7: IR absorption range

42

THE FINGERPRINT REGION

Although the entire IR spectrum can be used as a fingerprint for the purposes of comparing

molecules, the 600 - 1400 cm-1 range is called the fingerprint region.

This is normally a complex area showing many bands, frequently overlapping each other.

This complexity limits its use to that of a fingerprint, and should be ignored by beginners

when analyzing the spectrum. As a student, you should focus your analysis on the rest of the

spectrum that is the region to the left of 1400 cm-1.

3.5 Experimental Scheme:

In solvent extraction, there were 3 components: the basic component, polar addition and

Solvent.

Experiment # Basic Component Solvent Addition Polar Addition

1 Used Oil Benzene Water

2 Used Oil CCL4 Water

Then we mixed different solvents in different ratios with used lubricating oil.

43

Experiment # Basic

Component

Solvent Addition Polar Addition Solvent to Oil

Ratio

1 Used Oil Benzene Water 1:1

2 Used Oil Benzene Water 1:2

Re-refining of waste lubricating oil by solvent extraction

Experiment # Basic

Component

Solvent

Addition

Polar

Addition

Solvent to Oil

Ratio

Action after

Mixing

1 Used Oil Benzene Water 1:1 LLE

2 Used Oil Benzene Water 1:2 LLE

44

Resulting mixtures were tested analytically using Fourier Transform Infrared Spectroscopy

(FTIR) as analytical technique.

Experiment

#

Basic

Component

Solvent

Addition

Polar

Addition

Solvent to

Oil Ratio

Action

after

Mixing

Analysis

1 Used Oil Benzene Water 1:1 LLE FTIR

2 Used Oil Benzene Water 1:2 LLE FTIR

45

3.6 Experiments Performed:

Experiment # Oil

(ml)

Solvent Water

(ml)

Oil :

Solvent

1 100 50 ml CCL4 50 2 : 1

2 50 50 ml CCL4 50 1 : 1

3 100 50 ml Benzene 50 2 : 1

4 50 50 ml Benzene 50 1 : 1

5 40 20 ml CCl4 20 2 : 1

6 70 40 ml CCl4 50 1.75 : 1

7 20 10 ml CCl4 Brine

20 ml

2 : 1

46

Solvent Extraction With CCL4:

Figure 8: Extraction in lab

3.7 Experimental Results:

47

Figure 9: FTIR of fresh un-used motor oil

This is the FTIR spectrogram of un-used fresh motor oil.

48

Figure 10:FTIR of used motor oil from bike

Above graph is indicating IR spectra of used motor oil taken from bike. As this oil

was used to a very small extent and also conditions were not very severe due to less use of

bike, so this spectra is showing that there is not much difference between used and fresh

motor oil. So we decided to use a different source to obtain motor oil. SO we went ot market

and checked samples of used oil from different workshops and then obtained samples form

these workshops.

49

Figure 11:FTIR of used motor oil from market

Thisis the FTIR spectrogram of used motor oil. It is showing great amount of disorder as

compared to original un-used fresh motor oil.

A large number of peaks in the middle portion show unsaturated carbon chains that are

produced due to deterioration of saturated carbon chains due to severe conditions like high

temperature and abrasion in engine.

Figure 12: FTIR of treated oil with CCl4 in 1:1

50

Figure 13: Treated oil with benzene in 1:1

Figure 14: Treated oil with benzene in 2:1

51

Figure 15: Treated oil using brine as a polar addition and CCl4 in 2:1 (oil to solvent)

ratio

Figure 16: Two spectrograms comparison

52

In the graph, upper curve is showing used oil FTIR while lower curve is showing treated

motor oil.

Experimental Objective:

Our experimental objective is to eliminate peaks in the middle portion of graph as these are

peak showing unsaturated carbon cahins which were created due to use of oil in motros or

engines.

From figure 11 shown previously,

SO any experiment with its FTIR showing elimination of this middle portion will be the best

result.

BEST RESULT:

53

Figure 16: Two spectrogram comparison

This is the best result we got as the lower curve is showing diminishing of peaks in the

middle region which was our objective as described above. This result was obtained with

CCl4 sample.

Process Development Chapter 4

4.1 Process Description:

In this chapter, a process is explained for complete re-refining of plant developed

from literature review and experimental work. Process is developed keeping in mind

environmental factor and economics as top priorities.

4.1.1 Dehydration:

54

Firstly oil is dehydrated and sent to Liquid-Liquid Extraction column where

extraction is done with a solvent. Water becomes part of used oil due to poor collection

system in workshops even sometimes this used oil is kept in open drums in which rain water

could also be mixed. For dehydration, water is heated up to 105 oC so that water is

evaporated.

4.1.2 Solvent Extraction:

After dehydration, used oil goes to extractor where recycled solvent, fresh solvent and

polar addition i.e. water is also added. Here solvent extraction takes place. Detail designing of

extractor is provided in Designing chapter. Separation time is about 1 hour. Here two layers

appear, one is extract phase which Is mixture of solvent and oil while other is raffinate phase

which is mostly water along with some undesirable material of oil.

4.1.3 Solvent Stripping:

After extraction, Extract from extractor goes to stripping section where about 80%

solvent is stripped and recycled back. Stripping section is somehow similar to distillation

where the extract coming from extractor is heated just above the boiling point of solvent so

that solvent evaporates. After evaporation of solvent, it is passed through condenser where

solvent is again condensed.

55

Figure 17: Extraction using benzene in Lab

4.1.4 Ammonium sulphate Treatment:

The treated oil is then sent to next section where it is treated with Ammonium

sulphate for metal treatment. Ammonium Sulfate reacts with metals present in the oil and

forms solid compounds which are precipitated out. And we gets treated oil. It is a process for

reducing the ash and metal content in used motor oils by contacting the used motor oil with

an aqueous solution of ammonium bisulfate under conditions to react with the metal

compounds present to form separable solids.

Figure 18: Block Flow Diagram

56

57

Chapter # 5

Material Balance

Treatment of 10,000 L/day used-Motor oil

Basis of calculation 1 hr

Feed: used oil = 417 L/hr

Water = 297 L/hr

Solvent: CCl4 = 5714 L/day = 238 L/hr

In used oil saturates fraction is almost 90%

Therefore, saturates in used oil = 0.9 * 417L/hr = 375.3 L/hr

Extract: 535.826 L/hr

714 L/hr

58

CCl4 178.6 L/hr

Saturates 354.24 L/hr

Impurities 2.090 L/hr

Raffinate: 416 L/hr

Water 297 L/hr

Saturates 21 L/hr

Impurities 98 L/hr

Balance Around Liquid-Liquid Extractor

YA, a = 354/535 = 0.66

XA, a = 21/416 = 0.05

Two end points of operating line

(0.05 , 0) (0.525 , 0.661)

Oil Feed solvent feed = Raffinate Extract

L Xa + VbYb= LbXb + VYa

(714.58)(Xa) + (238) (0) = (178.754)(0.05) +

(535.826)(0.66)

59

Xa = 0.5074

Pick an intermediate point; ya = 0.2

Xa = 0.1624

Intermediate point (0.1624 , 0.2)

5.1 McCabe Thiele Diagram:

Operating Line

Table 8 Operating Line Data

XA YA

0.05 0

0.18 0.2

0.525 0.66

Equilibrium line

Table 9 Equilibrium Line Data

60

x y

0 0

0.05 0.19

0.1 0.33

0.15 0.43

0.2 0.52

0.25 0.59

0.3 0.65

0.35 0.7

0.4 0.74

0.45 0.78

0.5 0.81

0.55 0.84

0.6 0.87

0.65 0.89

0.7 0.91

0.75 0.93

0.8 0.95

0.85 0.96

0.9 0.98

0.95 0.99

1 1

2.2 Theoretical Plates:

61

Figure19: McCabe Thiele Theoretical Plates

5.3 Extractor Sizing:

Using model described in

Liquid-Liquid Extraction With andWithout a Chemical Reaction

byClaudia Irina KoncsagandAlinaBarbulescu

6.3.1The column diameter:

The diameter of the column is correlated with the processing capacity of the

column (theflow of the phases) and the flooding capacity. The synthetic form of

this correlation wasexpressed by Zhu and Luo (1996):

62

Qcis the continuous phase volumetric flow, [m3/s]

Qd- the dispersed phase volumetric flow, [m3/s]

Bmax is the flooding capacity, [m3/ m2.s]; considering the flow in the free

cross-sectional area of the column. The flooding capacity Bmax is in fact the

sum of the flooding velocities of phases; it depends on the physical properties of

the system: the density (ρcandρd), the viscosity (μc and μd) and the interfacial

tension σ.

k- the flooding coefficient, with values from 0.4 (dispersion column) to 0.8

(column equipped with structured packing); this coefficient would be kept as

high as possible, in order to increase the mass transfer rate and the processing

capacity of the column.

Feed:

Total feed = 1.983 * 10-4m3/s

Feed L/hr m3/s

used-oil 417 L/hr 1.157 * 10-4m3/s

Water 297 L/hr 0.826 * 10-4m3/s

63

5.3.2 Column Diameter:

Column Diameter: Dc =

= 0.65 m

5.3.3 Column Height:

Column Height = Volume / Area = 1.19 m3 /4 (0.65 m)2

= 3.586 m

Solvent CCl4 238 L/hr 0.661 * 10-4m3/s

64

Column Sizing:

Table 10 Column Sizing Data

Residence Time 1 hr

Liquid Holdup 952 L = 0.952 m3

25 % extra-space in column 0.238 m3

Extractor Volume (0.952 + 0.238) m3 = 1.19 m3

Column Height 3.586 m

65

Chapter # 6

Cost Estimation& Sizing

6.1 The Factorial Method of Cost Estimation:

Capital cost estimates for chemical process plants are often based on an estimate of the

purchase cost of the major equipment items required for the process, the other costs being

estimated as factors of the equipment cost. The accuracy of this type of estimate will depend

on what stage the design has reached at the time the estimate is made, and on the reliability of

the data available on equipment costs. In the later stages of the project design, when detailed

equipment specifications are available and firm quotations have been obtained, an accurate

estimation of the capital cost of the project can be made.

6.1.1 Procedure:-

1. Prepare material and energy balances, draw up preliminary flow-sheets, size major

equipment items and select materials of construction.

2. Estimate the purchase cost of the major equipment items. Use Figures 6.3 to 6.6 and Tables

6.2 and 6.3, or the general literature.

3. Calculate the total physical plant cost (PPC), using the factors given in Table 6.1

4. Calculate the indirect costs from the direct costs using the factors given in Table 6.1.

5. The direct plus indirect costs give the total fixed capital.

66

6. Estimate the working capital as a percentage of the fixed capital

7. Add the fixed and working capital to get the total investment required.

Table 6.1: Typical factors for estimation of project fixed capital cost

Table 6.2: Purchase cost of miscellaneous equipments

67

Figure 20: heat transfer area vs. exchanger’s cost

Table 6.3: Materials, pressure & type factors

68

Figure 21: Vessel height vs. equipment cost

Table 6.3:Materials, pressure & type factors

69

6.2 Sizing of Major Equipments:

6.2.1 Dehydration Tank:

Dehydration tank liquid holdup 417 L/hr = 0.417 m3

10% free space 0.0417 m3

Tank volume 0.4587 m3

6.2.2 Stripper:

Stripper volume 536 + (0.2 * 536) = 643.2 L=0.6 m3

Assume stripper diameter to be equals

to extractor diameter

0.65 m

Stripper height 0.6 m3 / 4 (0.65 m)2 = 1.8 m

6.2.3 Condenser:

Solvent stripped 143 L = 0.143 m3

70

Assume condenser’s length 0.25 height of stripper length

Condenser’s area = stripper’s area 4 (0.65 m)2 = 0.33 m2

6.2.4 Ammonium Sulfate tank:

Volume 355 + (0.2 * 355) = 426 L =

0.426 m3

6.3 Equipment Cost:

Using factorial method

Ce =CSn

71

6.3.1 Dehydration tank:

= 2400 * (0.4567)0.6

= 1503.58 $

6.3.2 Extractor:

Height = 3.586 m

Cost = 6000 * 1 *1 = 6000 $

6.3.3 Stripper:

Height = 1.8 m

Cost = 4200 $

6.3.4 Condenser:

Fixed tube sheet, carbon steel, Area = 0.33 m2

Cost = 2500 *1 *0.8

= 2000 $

6.3.5 Ammonium Sulfate tank:

Volume = 0.426 m3

Cost = 2400 * (0.426)0.6

= 1438.3 $

72

6.3.6 Total purchase equipment cost

PCE = 15142 $

Physical Plant cost (PPC) = PCE * 3.4

= 15142 * 3.4

= 51482.8 $

Fixed Capital = PPC * 1.45

= 51482.8 * 1.45

= 74 650 $

Working Capital = Fixed Capital + (5% of fixed capital)

= 74 650 $ + 3732.5 $

=78 382 $= Rs. 78 00 000

6.4 Operating Cost:

Raw oil cost = Rs. 30 per litre

CCl4 cost = Rs. 100 per litre

Ammonium price = Rs. 200 per Kg

Raw oil = 10 000 L/day

Solvent (CCl4) = 1142 L/day fresh solvent

73

Ammonium Sulfate = 660 kg/day

Cost

oil solvent Ammonium Sulfate

Rs. 300 000 Rs. 114200 Rs. 13200

Total Raw material cost per day = Rs. 300 000 + Rs. 114200 + Rs. 13200

= Rs. 4 27 400

Utilities cost = 4% of Raw material cost = Rs. 17 096

Labor charges =Rs. 300 per labor per day

For 10 labors charges = Rs. 3000

Plant operator salary = Rs. 450 per operator per day

For two operators = Rs. 900 per day

Engineer’s salary = Rs. 1000 per day (only one

engineer)

Overall Plant’s per Expenditure = Rs. 4 49 396

= Rs. 4 50 000 (approx.)

Treated oil price in market = Rs. 80

Revenue Generated = Rs. 6 78 560 (approx.)

Profit per day = Rs. 2 28 560

74

Chapter 7

Industrial Application

1. The used motor oil after reaction with ammonium sulfate can be further treated with an

adsorbent and then optionally hydrotreated to procedure an oil product suitable as a fuel

as a feedstock for lubrication oil compositions

2. Further treatment of oil under hydrogenation conditions to remove additional

contaminants and produce a marketable low ash oil product

3. The metals precipitated with ammonium sulfate can be recovered. Oil can be heated and

intermixed in a reaction zone with a heated aqueous solution pf ammonium sulfate to

precipitate metal compounds

75

References:

I. Liquid-Liquid Extraction With and Without a Chemical Reaction by

Claudia Irina Koncsag and AlinaBarbulescu

II. Waste automotive lubricating oil reuse as a fuelvol 1by Steven Chansky

III. Waste engine oils: Refining and Energy Recovery by Francois Audibert

IV. Design Aspects of Used Lubricating Oil Re-refining by FirasAwaja

V. Reclaiming Used Motor Oil by Marvin M. Johson

VI. Fourier Transform Infrared Spectrometry by Peter R. Griffiths

VII. Introduction to Fourier Transform Infrared Spectrometry thermo nocolet

corporation (2001)

VIII. Re-Refining of Waste Lubricating Oil by Solvent Extraction by HASSAN

ALI DURRANI, MUHAMMED IBRAHIM PANHWAR, AND

RAFIQUE AKTHAR KAZI

IX. Chemical Engineering Design 4th Ed by SINNOTT

X. FT-IR Analysis of Used Lubricating Oils – General Considerations by

Michael C. Garry, John Bowman, Thermo Fisher Scientific, Madison

XI. Virgin and Recycled engine oil differentiation: A spectroscopic study by

Mohammad A. Al-Ghouti, Lina Al-Atoum

XII. Lubricants and Lubricationby Theo Mang, WilfriedDresel