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Lubricating Oils, Greases and Petroleum Products Manufacturing Handbook

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Lubricating Oils, Greases and Petroleum Products Manufacturing Handbook

Author: NIIR Board of Consultants & Engineers
Format: Paperback
ISBN: 9789381039892
Code: NI314
Pages: 376
Price: Rs. 1,475.00   US$ 150.00

Published: 2018
Publisher: NIIR PROJECT CONSULTANCY SERVICES
Usually ships within 5 days



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Lubricating oils are specially formulated oils that reduce friction between moving parts and help maintain mechanical parts. Lubricating oil is a thick fatty oil used to make the parts of a machine move smoothly.
The lubricants market is growing due to the growing automotive industry, increased consumer awareness and government regulations regarding lubricants. Lubricants are used in vehicles to reduce friction, which leads to a longer lifespan and reduced wear and tear on the vehicles. The growth of lubricants usage in the automotive industry is mainly due to an increasing demand for heavy duty vehicles and light passenger vehicles, and an increase in the average lifespan of the vehicles. As saving conventional resources and cutting emissions and energy have become central environmental matters, the lubricants are progressively attracting more consumer awareness.
Greases are made by using oil (typically mineral oil) and mixing it with thickeners (such as lithium-based soaps). They may also contain additional lubricating particles, such as graphite, molybdenum disulfide, or polytetrafluoroethylene (PTFE, aka Teflon). White grease is made from inedible hog fat and has a low content of free fatty acids. Yellow grease is made from darker parts of the hog and may include parts used to make white grease. Brown grease contains beef and mutton fats as well as hog fats. Synthetic grease may consist of synthetic oils containing standard soaps or may be a mixture of synthetic thickeners, or bases, in petroleum oils. Silicones are greases in which both the base and the oil are synthetic.
Asia-Pacific represents the largest and the fastest growing market, with volume sales projected to grow at a CAGR of 5% over the analysis period. Automotive lubricants represents the largest product market, with engine oils generating a major chunk of the revenues. The market for industrial lubricants is supported by the huge demand for industrial engine oils and growing consumption of process oils.
The major content of the book are Food and Technical Grade White Oils and Highly Refined Paraffins, Base Oils from Petroleum, Formulation of Automotive Lubricants, Lubricating Grease, Aviation Lubricants, Formulation and Structure of Lubricating Greases, Marine Lubricants, Industrial Lubricants, Refining of Petroleum, Lubricating Oils, Greases and Solid Lubricants, Refinery Products, Crude Distillation and Photographs of Machinery with Suppliers Contact Details.
This book will be a mile stone for its readers who are new to this sector, will also find useful for professionals, entrepreneurs, those studying and researching in this important area.


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Contents

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1. Food and Technical Grade White Oils and Highly Refined Paraffins

1. WHITE OILS
•Introduction
2. MANUFACTURE BY ACID TREATMENT
3. HYDROTREATMENT PROCESSES
•Introduction
•Second-Stage Operation
•Products
•Product Specifications for Polynuclear Aromatics
4. REFINED WAXES

2. Base Oils from Petroleum
1.     INTRODUCTION
2. BASE OIL COMPOSITION
•Components of Crude Oil
•Characteristics of the Hydrocarbons for Lubricant Performance
•Crude Oil Selection for Base Oil Manufacture
3. PRODUCTS AND SPECIFICATIONS
•Introduction
•Physical Properties - Viscosity •Chemical Properties - Oxidation •Base Oil Categories: Paraffinics •Safety of Petroleum Base Oils
4. CONVENTIONAL BASE OIL MANUFACTURING METHODS
•Historic Methods
•Base Oil Manufacture in a Modern Refinery
•Base Oil Production Economics
•Distillation
•De-asphalting
•Solvent Extraction
•Solvent De-waxing •Finishing
5. MODERN CATALYTIC PROCESSES
•Severe Hydrotreatment
•Special Base Oils from Hydrocracking
•Special Base Oils by Wax Isomerisation
•Catalytic De-waxing
•Iso-De-waxing
6. CATEGORISATION OF BASE OILS

3. Formulation of Automotive Lubricants          
1.   INTRODUCTION
2. PASSENGER CAR ENGINE OILS
•Passenger Car Engine Types
•Passenger Car Trends and Emission Legislation
•Formulation and Functions of a Passenger Car Engine
Oil (PCEO)
•Lubricant Formulation Trends
•Passenger Car Lubricant Specifications and Evaluating Lubricant Performance
3. Heavy-Duty Diesel Engine Oils
•Heavy-Duty Trends and Emission Legislation •Heavy-Duty Engine Strategies Applied to Reduce Exhaust Emissions
4. MOTORCYCLES AND SMALL ENGINES
•Introduction
•Overview of Two-Stroke Lubricants
•Two-Stroke Specifications
•Four-Stroke Motorcycle Lubricants-Overview
•Four-Stroke Motorcycle Specifications
•Lubricant Composition and Impact on Clutch Performance
•Emissions and the Future

4. Lubricating Grease                              
1.   INTRODUCTION TO LUBRICATING GREASE
2. STRUCTURE AND RHEOLOGICAL PROPERTIES
•Structure of Grease •The Rheology of Grease
3. THE CHEMISTRY OF GREASE
•Introduction •Base Fluids in Grease •Grease Thickeners •Grease Manufacturing
4. APPLICATIONS •Introduction •Grease as a Lubricant •Grease as a Sealant •Grease as a Matrix •Grease as a Corrosion Inhibitor •Benefits of Grease

5. Aviation Lubricants                              
1.   INTRODUCTION
2. PISTON ENGINE LUBRICANTS
•Lubrication of Rotary Engines
•Lubrication of Conventional Aircraft Piston Engines
3. AVIATION GAS TURBINE LUBRICANTS
•Base Oil Technology
•Anti-oxidant Additives
•Anti-wear and Load-Carrying Additives
•Corrosion Inhibitor Additives
•Anti-foam Additives
• Specifications
4. AIRCRAFT HYDRAULIC FLUIDS
•Introduction
•Hydrocarbon-Based Hydraulic Fluids
•Phosphate Ester-Based Hydraulic Fluids
5. AIRCRAFT GREASES
6. HELICOPTER TRANSMISSION LUBRICANTS

6. Formulation and Structure of Lubricating Greases  
1.   INTRODUCTION
2. APPLICATIONS
•Land Transportation •Industrial Applications •Aerospace Applications •Radiation 3.GELLANTS
•Simple Soaps •Complex Soaps •Synthetic Soaplike Salts •Noncarboxylic Salts •Dyes and Pigments •Polymers •Inorganic Gellants
(viii)

4. OILS
5. ADDITIVES
•Antioxidants
•Anticorrodants
•Antiwear and Extreme-Pressure Agents
•Other Additive
6. FUNDAMENTAL PROPERTIES
•Structure
•Internal Structure
•Get Network Structure
•Gross Structure
•Flow
•Plastic Flow
•Thixotropy
•Work Breakdown
•Lubrication Mechanisms
•Oxidation

7. Marine Lubricants                              
1.   INTRODUCTION
2. MARINE DIESEL ENGINES
•Classification by Engine Speed •Slow-Speed Engines •Medium-Speed Engines
3. FUEL OIL
4. BASE OILS
5. ADDITIVES
•Main Additive Types
•Alkaline Detergents
•Dispersants
•Antioxidants
•Corrosion Inhibitors
•Anti-Wear, Load-Carrying and Extreme Pressure Additives
•Pour-Point Depressants
•Anti-Foam Additives
6. PROPERTIES AND FORMULATION OF MARINE
LUBRICANTS
7. SYSTEM OILS
•Introduction
•Demulsibility
•Rust and Corrosion Protection
•Oxidation and Thermal Stability
•Load Carrying

(ix)
8. CYLINDER OILS
•Introduction •Colloidal Stability •Acid Neutralisation •Spreadability •Engine Tests •Field Tests
9. TRUNK PISTON ENGINE OILS
•Filterability
•Heavy Fuel Engine Tests 10. ANALYSIS OF IN-SERVICE OILS •Introduction •Density •Viscosity •Flash Point •Insolubles •Base Number •Water Content •Wear Metals

8. Industrial Lubricants                            
1. INTRODUCTION
•General aspects of Industrial Lubricants •Classification of Industrial Lubricants
2. BEARING LUBRICANTS
•Bearings
•Gaseous Lubricants
•Greases
•Solid Lubricants
3. COMPRESSOR LUBRICANTS
•General Description •Lubricants for Gas Compressors •Vacuum Pump Lubricants
4. INDUSTRIAL GEAR LUBRICANTS
•General Description •Lubricants
5. TURBINE LUBRICANTS
•General Description •Industrial Turbine Lubricants
6. METALWORKING LUBRICANTS
•General Description of Metalworking Processes •Lubricant types for Metal Forming Processes •General Lubricant types for Metal Cutting Processes

(*)
7. SPECIALITIES •Process Oils •Textile Oils •Slide Way Oils •Cylinder Oils •Other Lubricants and related Products

9. Refining of Petroleum                          
1.   INTRODUCTION
2.   EMULSION BREAKING
3.   DISTILLATION
4. NATURAL GAS AND NATURAL GASOLINE
5.   CRACKING
6.   POLYMERIZATION
7.   ALKYLATION
8.HYDROGENATION PROCESSES 9. AROMATIZATION
10.ISOMERIZATION
11. FINISHING PROCESSES
12. TREATMENT OF GASOLINE
13. BLENDING OF GASOLINES
14. KEROSENE
15. LUBRICATING OIL

10. Lubricating Oils                                  
1.   INTRODUCTION
2.   HYDRO DYNAMIC LUBRICATION
3.   BOUNDARY LUBRICATION
4.ZN/P CURVES
5. VISCOSITY
6. DIMENSIONS AND UNITS OF VISCOSITY
7. THEORY OF VISCOSITY
8. MEASUREMENT OF VISCOSITY
9. VISCOSITY-TEMPERATURE-PRESSURE RELATIONS
10. VISCOSITY OF BLENDS
11. VISCOSITY INDEX
12. VISCOSITY TEMPERATURE COEFFICIENT
13. SIGNIFICANCE OF VISCOSITY AND VISCOSITY INDEX
14. CLOUD AND POUR POINT
15. SIGNIFICANCE OF CLOUD AND POUR POINT
16. ADDITIVES
17. VISCOSITY INDEX IMPROVERS

(XI)
18.   POUR POINT DEPRESSANTS
19.   OIL CLASSIFICATION SYSTEMS
20. OILINESS
21. OILINESS CARRIERS
22. EXTREME PRESSURE LUBRICANTS
23. SLUDGE AND LACQUER FORMATION
24. ANTI-OXIDANTS
25. CORROSION INHIBITORS
26. DETERGENTS
27. COMMERCIAL ADDITIVES
28. BENCH TESTS FOR OXIDATION STABILITY
29. ACIDITY
30. CARBON-FORMING TENDENCIES
31. WORK FACTOR TEST
32. OIL VOLATILITY
33. SULFUR
34. CLEANLINESS
35. GRAVITY
36. COLOR
37. DIBASIC ACID ESTERS
38. ORGANO-PHOSPHATE ESTERS
39. SILICATE ESTERS
40. SILICONES
41.POLYGLYCOL ETHER COMPOUNDS
42.FLUORINATED AND CHLORINATED HYDROCARBONS
43. EFFECT OF RADIATION

11. Greases and Solid Lubricants                  
GREASES
1.     Definition
2.   Applications for Grease Lubrication
3.   Structure and Properties of Greases
4.   Materials Used in Making Greases
5.     Characteristics of Greases from Various Metallic Soaps
6.     Greases from Nonsoap Thickeners
7.     Pure Petroleum Greases
8.     Grease Additives and Fillers
LABORATORY TESTING OF GREASES
9.     Consistency
10.     Apparent Viscosity
11.     Dropping Point
12.     Oxidation Stability
13.       Water Resistance
14.       Extreme Pressure Qualities
15.       Grease Specifications
SOLID LUBRICANTS
16.       Introduction
17.       Laminar Solids
18.       Organic Compounds
RADIATION DAMAGE TO GREASES
12. Refinery Products                            
1.   LOW-BOILING PRODUCTS
2.   GASOLINE
3.   GASOLINE SPECIFICATIONS
4.   DISTILLATE FUELS
•Jet and Turbine Fuels •Automotive Diesel Fuels •Railroad Diesel Fuels •Heating Oils
5. RESIDUAL FUEL OILS

13. Crude Distillation

1.   DESALTING CRUDE OILS
2.   ATMOSPHERIC TOPPING UNIT
3.   VACUUM DISTILLATION
4.   AUXILIARY EQUIPMENT
5.   CRUDE DISTILLATION UNIT PRODUCTS

14. Photographs of Machinery with Suppliers    



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Sample Chapters


(Following is an extract of the content from the book)
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 Food and Technical Grade White Oils and Highly Refined Paraffins

WHITE OILS

Introduction

The term “while oil” refers lo highly refined distillate fractions

in the lubes boiling range whose water white color (and

therefore the “while” descriptor) is due to the almost complete

absence of aromatics as well as sulfur- and nitrogen-containing

compounds. While mineral oils, also known as “paraffin oil,”

“liquid paraffin,” and “while mineral oil,” are liquids at room temperature

and are predominantly mixtures of isoparaffins and

naphthenes with lesser amounts of n-paraffins. White oils are

manufactured for use in agriculture and the chemicals and

plastics, textiles, food, Pharmaceuticals, personal care and

cosmetics industries, and their purity is regulated in most

countries. The manufacturing objective is to produce oils of high

purity and low toxicity with the composition, being almost entirely

saturated hydrocarbons. Toxicity specifications require

polynuclear aromatic hydrocarbons (PAHs) to be at very low levels.

White mineral oils were first developed by a Russian

chemist, J.Markownikoff, and the first plant for their manufacture

was set up in Riga, Latvia, around 1885. When European supplies

to the United States were cut off during World War I, the L.

Sonneborn Company was the first US company to begin to

manufacture them and used Pennsylvanian crude. This was later

followed by the Pennsylvania Refining Company (Penreco) and

many others. The major North American manufacturers now are

Sonneborn, Lyondell-Citgo, Penreco and Petro-Canada.

White oils are of either “technical” or “food/medicinal”

grade, with the food/medicinal grade having tighter specifications

and therefore requiring more stringent processing. Technical grade

white oils are employed as components of nonfood articles

intended for use in contact with food (e.g., in food machinery

lubricants) and in the United States are governed by Food and

Drug Administration (FDA) regulations (21 CFR 178.3620(b)). For

technical grade white oils, color must be better than 20 on the

Saybolt scale (ASTM D156), however, most technical grade

material made today is +30, the same as food grade.

Food/medicinal grade specifications (21 CFR 172.878) are

designed such that products meeting these specifications can

be safely used in food and pharmaceuticals. The specifications

control PNA levels by the UV absorption limits given in Table 2

and by the carbonizable substances lest (ASTM D565).

Food/medicinal oils are frequently referred to as meeting

United Slates Pharmacopeia (USP) or National Formulary (NF)

specifications, usually written as “meets USP/NF specifications.

USP and NF specifications differ only in specific gravity and

viscosity. USP oils must have specific gravities between 0.845

and 0.905 at 25°C and have viscosities greater than 34.5c St at

40°C. NF oils must have viscosities less than 33.5 c St at 40°C

and must have densities between 0.818 and 0.80 at 25°C. Further

details on specifications are provided later. In addition, food grade

while oils must satisfy the following:

Second-Stage Operation

The second stage is said to operate “cold” (i.e., greater than

150°C but less than 340°C) and universally employs a very active

hydrogenating catalyst (e.g., a noble metal such as platinum or

lead or a Raney nickel-type catalyst) whose purpose is to

hydrogenate remaining aromatics, particularly polyaromatics. The

“cold” operation is to keep the aromatic saturation temperature

in the region of kinetic control, particularly for polyaromatics.

At higher temperatures, thermodynamic control can take over

and cause reversible formation of polyaromatics from three-ring

and higher naphthenes. This eventuality would cause the product

to fail specifications for polynuclear aromatics levels. If the

reactor temperature is too low, the product may also fail

specifications due to kinetic failure (i.e., insufficient removal of

PNAs).

Process operating conditions for the BASF second-stage unit

are given as a 120°C to 300°C reactor temperature, 10 to 20 MPa

hydrogen partial pressure and 0.1 weight hourly space velocity.

In the case of both stages, increased hydrogen partial pressures

will obviously assist in meeting product specifications more

easily.

Products

To address any concerns that there might be chemical

differences between white oils produced by the acid process and

hydrotreatment, the mass spectra of Lyon-dell Duotreat products

were compared with those from acid treatment. The authors

concluded that there was indeed little difference at the same

viscosity level. White oils made by acid treating can have higher

sulfur levels than those that are produced by hydrotreating.

Table 4, a comparison of the mass spectra of white oils

produced from lube hydrocracking and SK’s fuels hydrocracking

process for lubes, which entails severe hydrocracking followed

by hydroisomerization and hydrofinishing, shows higher paraffin

(presumably essentially all isoparaffins) in the SK product compared

with the hydrocracked material and lower polycyclic naphthene

content. The SK product will also obviously have higher

VIs (which is not among the white oil specifications).

REFINED WAXES

Solvent dewaxing produces an initial wax, known as slack wax,

that contains substantial quantities of oil up to 20% by volume. A

second treatment of the wax, essentially another “dewaxing” step

called deoiling, produces essentially oil-free wax and as a by-product,

“footes oil” consisting of low melting point paraffins and naphthenes.

Deoiled wax from hydrocrackates will contain only parts per million

quantities of nitrogen and sulfur compounds. From solvent refined

oils, the level of these impurities in deoiled wax will necessarily be

higher. In both deoiled wax cases, further treatment is necessary to

meet food grade standards.

Feedstocks to dewaxing units are generally waxy distillates

intended for lube base stock production but dewaxing to produce

wax may be performed on crude distillates if the wax content is

high enough.

Formulation of Automotive Lubricants

INTRODUCTION

This chapter discusses the main influences on current and

future light-duty (passenger) and heavy-duty (truck) vehicle

engine oils and also small engines for motor-cycles/light appliances

in terms of engine design, emissions and fuel economy. This

is followed by a detailed discussion of lubricant composition and

performance assessment.

2. PASSENGER CAR ENGINE OILS

Passenger Car Engine Types

Internal combustion engines, ICE, for light vehicles can be

divided into two main types, gasoline and diesel although other

types of engine are emerging. The gasoline engine still dominates

most light-vehicle markets today although diesel popularity in

Europe now accounts for more than 50% of new light-vehicle

sales.

Diesel and gasoline engines share many similarities in their

mode of operation and in their component parts. However, there

are some important differences that ultimately impact on their

lubricant requirements, namely the fuel used, mode of ignition,

temperature of combustion, exhaust gas composition and the

resulting combustion products. The soot produced during diesel

combustion is at the heart of the differences in the lubrication

requirements between gasoline and diesel vehicles and this soot

also affects exhaust emission handling.

Passenger Car Trends and Emission Legislation

The engine segment has classically been driven by targets

set by the Original Equipment Manufacturers, OEMs including

such targets as fuel economy, longer lubricant drain intervals,

engine durability and cost of ownership. These targets attempt

to simultaneously meet the needs of vehicle manufacturers,

vehicle owners and government legislators.

In recent decades, the OEM requirements have been

supplemented by the need to meet government vehicle emission

legislation. Future legislation will penalise the sale of vehicles

that do not meet the fuel economy and emission standards of

the time. As a general principle, this requirement applies globally

but there are regional variations in these aspirational targets.

Air quality has historically been the main driver in both North

America and Europe and all engine manufacturers are required

by legislation to meet targets for emissions of CO, NOx particulates

and hydrocarbons. Additionally in America, OEMs are

required to meet Corporate Average Fuel Economy (CAFE), targets

or face stiff financial penalties.

Legislative trends - air quality and carbon emissions: Existing

exhaust after-treatment technology has already enabled more

than a 90% reduction in emissions related to local air quality.

The future challenge is to improve fuel economy and reduce

carbon dioxide emission levels. The developed world has fuel

economy/C02 targets for the end of the decade and beyond and

OEMs will have to meet these targets as an average across their

fleets. However, when combined these improvements will require

further drivetrain friction reductions, aero-dynamic improvements,

reduction in tyre rolling resistance, etc. Engine hardware

will also evolve, for example engine downsizing, increased exhaust

gas recirculation, more turbo/supercharging and advanced

fuel injection systems. However, even when combined, these

improvements are not expected to achieve the new emissions

targets and consequently OEMs will have to develop new powerplant

technologies. Increasing emphasis on vehicles with significantly

reduced emissions will lead to a variety of new competing

technologies. Examples being considered include electric

vehicles, hydrogen internal combustion, homogenous charge

compression ignition (HCCI) and carbon-neutral biofuels.

Lubricant Formulation Trends

Before 2001, the components used for specific lubricant

functions had remained relatively consistent since the introduction

of ashless dispersant technology in the 1960s. However,

recently introduced emissions legislation mandates the use of

exhaust after-treatment for both gasoline and diesel light

vehicles in many parts of the developed world, and this requirement

affects component selection for modern formulations.

Three-way catalysts are used in gasoline cars to control the

emissions of hydro-carbons, carbon monoxide and nitrogen

oxides. Oxidation catalysts and diesel particulate filters. DPFs,

are used in diesel vehicles to control the emissions of soot

particles, hydrocarbons, carbon monoxide and nitrogen oxides.

All of these after-treatment devices are sensitive to additive

components of the lubricant.

‘Low SAPS’ engine oil technologies: Low SAPS technologies

are being intro-duced primarily in markets with both a highdiesel

population and high-quality diesel fuel. Legislators in

markets with high-diesel populations have driven diesel fuel

quality to higher levels. That same legislation is now driving

reduced tailpipe emissions via after-treatment devices such as

diesel particulate filters. These filters can be blocked by metallic

ash formed from oil burned during the combustion process. As

a consequence of the introduction of DPFs, modem formulations

are now using less of traditional ash-containing components.

Ash for oils is measured by a standard method known as

‘Sulphated Ash’ via the ASTM D874 procedure.

Passenger Car Lubricant Specifications and Evaluating

Lubricant Performance

Lubricant specifications: The required performance of a lubricant

in a specific application is defined by a specification. For

passenger car oils, the specifications are normally set by a

regional industry body such as API, ACEA, JASO or by a vehicle

manufacturer such as Ford, VW, Mercedes Benz. In some other

applications such as heavy-duty lubricants and transmissions,

specifications may also be set by a military organisation or by a

Tier l supplier to the vehicle manufacturer. Irrespective of the

organisation defining the specification there are common areas

against which the passenger car lubricant will be measured.

Passenger car lubricant performance evaluation: Specifications

usually contain a mixture of physical/chemical requirements and

performance properties. Physical/chemical limits include viscosity

at multiple temperatures, volatility, pour point and limits

on chemical components such as phosphorus and chlorine.

Heavy-Duty Trends and Emission Legislation

In general, emission legislation continues to drive hardware

development in the automotive industry. In future, global legislation

will mandate progressively tighter limits for NO2, particulates

and COx. This is forcing OEMs to make significant

advances in engine and exhaust after-treatment technology to

meet the legislated exhaust emission requirements. This is

further complicated since there is no harmonisation of current

global emissions standards: Figure 3 shows the state of the

heavy-duty legislated emissions requirements around the world.

Many countries in emerging markets are using the Euro

legislation to set their emissions limits, phasing them in a few

years after they are implemented in Europe. 'Off-highway' limits

are also being tightened and again these tend to lag behind the

'on-highway' limits.

MOTORCYCLES AND SMALL ENGINES

Introduction

The lubricant requirements for motorcycles and small engines

can be broadly split by their engine types: i.e. two-stroke or

four-stroke. Small engines cover lightweight portable equipment

such as chainsaws through to applications such as personal

watercraft or snowmobiles.

Overview of Two-Stroke Lubricants

Historically, the two-stroke engine has been a dominant

force in the world of motor-cycling and portable equipment due

to its high power-to-weight ratio, simplicity of construction and

low cost compared to equivalent sized four-stroke engines.

Aviation Lubricants

INTRODUCTION

Three factors dominate all aspects of aircraft design. First,

the need for the highest possible reliability due to the inherent

higher risk and potentially catastrophic consequences of in-flight

failure. Second, the need to minimise weight and volume of all

components, resulting in high specific loading in all mechanisms.

Therefore, there is high specific power dissipation so that operating

temperatures are high. Third, the extreme range of environmental

conditions encountered from –60°C on the ground, or –

80°C in the stratosphere, to over 200°C skin temperatures in

supersonic aircraft. Pressures can range from over 1 bar down

to less than 10 mbar. An example is aircraft wheel hearing

grease which can be subjected to a cold soak during long-haul

flights but then rapidly subjected to high temperatures generated

by the brakes on landing.

Because of these factors, the lubrication requirements of

aircraft are generally very critical. Only in a few cases can

lubricants developed for non-aircraft applications be used

satisfactorily in aircraft. This has not always been the case; the

mineral oil or castor oil lubricants used in the earliest aircraft

were all standard automotive or marine products.

World War I led to the recognition of the need for special

lubricants in aircraft engines. Previously, aircraft rarely climbed

to higher than a few thousand feet and engine mechanical reliability

was so poor that lubricant reliability was not a limiting

factor. But by 1918 aircraft were flying regularly as high as 18,000

feet and flights often lasted up to 5 h.

Castor oil lubricants in rotary engines gave no problems,

for reasons explained later but long-range bombers and flying

boats did not use rotary engines and their needs led to a steady

improvement in engine lubricant quality.

The divergence between ordinary automotive engine

lubricants and aircraft engine lubricants widened during the

1930s when there was a steady increase in the use of additives

in automotive lubricants. Additives were considered undesirable

for aircraft use and aircraft engine lubricants remained largely

additive free.

The introduction and development of gas turbine engines

led to the development of new lubricants. While the early gas

turbine engines ran successfully on mineral oil lubricants, and

in fact many Russian aircraft engines still operate on such lubricants,

the demand for higher specific thrust, with the concomitant

high operating temperatures, needed lubricants with better

thermal stability. Carboxylic esters were developed which, with

yet further improvements, are still used today. These lubricants

are also used in aeroderived industrial and marine gas turbines,

meaning that for the first time lubricants developed for aircraft

were used in other applications.

PISTON ENGINE LUBRICANTS

Lubrication of Rotary Engines

In the aviation context, the term ‘rotary engine’ refers to the

class of reciprocating piston engines where an assembly of radially

mounted cylinders rotates around a stationary crank-shaft.

Strictly, such engines should be referred to as ‘rotating-radial

engines’, but ‘rotary engines’ have become the accepted term, an

example is shown in Figure 1. Rotary engines were a major factor

in aircraft propulsion for only 10 years but during that short period

they made a vital contribution to World War I military aviation.

The first aircraft rotary engine was a seven-cylinder Gnome used

by Louis Paulhan in a Voisin in June 1909. By 1917 they were

used in thousands of many of the best British and French scout

(fighter) aircraft. By 1925 production had virtually ceased, although

some remained in service until about 1930.

Because of the difficulty in providing a controlled lubricant

supply to the rotating cylinder assembly, lubricant was supplied

in the fuel feed. High centrifugal forces caused rapid lubricant

loss from the piston/cylinder interface so that the technique of

dissolving a mineral oil in the fuel, as in modem small twostroke

engines would leave an inadequate oil film on the cylinder

walls.

Lubrication of Conventional Aircraft Piston Engines

Apart from the rotary engines described above, piston engines

can all be classified as radial or in-line. In-line engines may have

either one bank of cylinders, horizontal or vertical, or they may

have two or more banks in various arrangements, Figure 2.

Radial engines may have one, two or four rings of cylinders,

each containing between three to nine cylinders mounted radially

about an axis parallel to the direction of flight. Figure 3, with

always an odd number of cylinders in each ring.

Ashless additive development has reduced the risk of solid

deposit formation and ashless dispersants, anti-oxidants and

anti-foam agents are now permitted in most engines. Nondispersant

mineral oils are now used primarily for older aircraft

and as a running-in oil for new engines or after overhaul.

The viscosity characteristics of the oil are important High

viscosity is needed at high operating temperatures because of

high specific power and consequential high bearing loads. Good

low-temperature performance is also required because aircraft

are often stored outdoors und must be capable of stalling after

a long overnight soak at low ambient temperatures. The lubricant

must have a low pour point as well as good temperature-viscosity

characteristics, that is a high viscosity index. Good viscositytemperature

characteristics are obtained by using highly refined

paraffinic basestocks and ashless dispersants can give some

viscosity index improvement. In spite of this, oil viscosity at low

temperatures is usually too high to allow the engine to respond

satisfactorily when increased power is required. It may even be

too high for the engine to be started at all and leads to several

constraints on engine operation:

These problems can now be alleviated to some extent by

the use of a multi-grade engine lubricant. The use of multi-grade

oils, 15W/50 and 20W/50 has continued to grow since their

introduction in 1979 but single-grade products still have a strong

following in the industry. Single versus multi-grade discussions

are still hot topics among pilots and mechanics alike and are

frequently the subject of trade publication articles. Some multigrades

are marketed as ‘semi-synthetic’ and some are not - the

desirability of synthetic oils in aircraft piston engine oils is also

often debated. A separate ‘class’ of products has come to the

market that contain a pre-blended supplemental anti-wear

additive that meets the requirements of (Airworthiness Directive)

AD 80 04 03 R2, paragraph b.l. The AD applies to certain (mostly

0-360 family) Lycoming engines that require additional cam and

lifter wear protection provided by Lycoming additive part no. LW-

16702 (TCP). Anti-corrosion additives are also now included in

some formulations to help protect against corrosion during

extended idle periods.

Base Oil Technology

Lubricants for the early gas turbine engines were essentially

highly refined mineral oils, a natural extension from the piston

engine lubricant technology available in the early 1940s. Such

an oil is still specified today in Defence Standard 91-99, UK MoD

Grade OM-11 and consists of ‘pure refined mineral oils with

0.05-0.10% stearic acid’ to enhance load-carrying/anti-wear and

anti-corrosion properties. It can also contain an anti-oxidant

which, in common with many mineral-based fluids, is the

‘hindered phenol’ type. Although not in widespread general use

as a gas turbine lubricant for many years it was still used by

the RAF in the Rolls-Royce Avon engines of the Canberra aircraft

until 2006.

However, rapid development of the gas turbine engine and

the quest for greater power resulted in higher operating

temperatures of the lubricated components and the mineral

based lubricants of the day could not withstand such temperatures

for sufficient lengths of time. The UK and the USA made

no real effort to develop mineral-based lubricants further. The

Soviet Block has continued development of mineral-based

lubricants, some of which are still in use today in Russian    

aircraft. However, this chapter concentrates on those lubricants

developed and used in western aircraft engines.

In the UK and the USA the focus for lubricant development

turned to ester-based synthetic lubricants. In the 1930s and

1940s German scientists, led by Professor Zorn had conducted

research into using di-esters and polyol esters as lubricants

Compared with mineral lubricants, ester-based lubricants had

better thermal and oxidative stability in addition to good lowtemperature

properties without the need for pour-point depressant

additives. In the 1950s both the UK and the US militaries

produced specifications for turbine lubricants based on di-esters.

The UK initially concentrated development on lubricants for

turbo-props where the load-carrying requirements of the

reduction gears used in these turbo-props required a higher

viscosity lubricant. This led to the development of a polyglycol

ether-thickened 7.5 cSt at 100°C lubricant. The USA focused on

turbo-jets to develop a 3 cSt lubricant. Despite the differences

in viscosity both lubricants were based on di-ester technology.

 

Formulation and Structure of Lubricating Greases

INTRODUCTION

Lubricating greases attract little attention from their beneficiaries

because they are usually hidden away in inner joints,

gears and bearings and are expected to do their job for a long

time without fail. But their job is critical and when they do fail

even the most expensive and elaborate machinery fails with

them. When machines are designed to run colder, hotter, longer,

faster or farther away than before, they require lubricating

greases equal to the new stresses. The development of such new

lubricants requires a continued application of advanced tools of

organic chemistry, physical chemistry and engineering, sometimes

far out of proportion to the market potential for the

finished product.

2. APPLICATIONS

Some applications of lubricating greases are common to

several end uses and can be considered for their general

requirements.

Rolling (“antifriction”) bearings reduce starting friction

compared with sliding bearings but the rolling elements still slide

to some extent against retainers and raceways. As a result, they

need lubrication. The increasing demands made on rolling

bearings by higher speeds, miniaturization and extreme temperatures

in turn increase demands on their lubricants. These

lubricants are often greases. They must have enough solidity

despite working, heating and oxidation not to leak out but enough

fluidity when sheared by the rotating bearing to lubricate its contacting surfaces without fail.

The consistency of a grease is its most important property

in bearings, especially if we think of it broadly as the constancy

of the consistency over a wide range of time, speed and temperature.

A consistency or yield stress equivalent to the National

Lubricating Grease Institute (NLGI) No. 2 Grade (ASTM cone

penetration 265—295) is most generally useful in hand-packed

rolling bearings. NLGI No.1 Grade. greases (penetration 295–

325) are more often used in centrally lubricated bearings. Softer

greases churn and liquefy during bearing rotation; stiffer ones

are difficult to charge into bearings and to rotate in them.

Stiffened consistency achieved by milling of greases during

manufacture does not lengthen their life in ball bearings; high

concentration of gellant is more important. The most important

causes of loss of consistency in bearings are churning promoted

by heat softening of the grease or over-filling of bearing

housings, water contamination and mixing of incompatible

greases. Large losses in consistency and melting temperature

result from contamination by even small portions of foreign

greases. Figure 1 shows graphically the effect of mixing on the

melting temperature of soap-gelled greases.

Industrial Applications

The industrial grease market is feeling some antigrease

pressure like that in the automotive market. Here it takes the

form of increasing centralized lubrication, mist lubrication, plastic

bushings and bulk handling. But the concurrent increase in

industrialization and automation helps to keep net consumption

nearly constant at about 300 million pounds of grease per year.

Centralized grease lubrication systems are in all large,

modern factories that have many bearings to lubricate. For big

consumers, such as steel mills, the grease is now delivered in

4000-6000-lb. kettles and charged directly to the lubricant lines.

Two problems have arisen in centralized systems. One, the

difficulty of predicting pressure drops for greases in long lines,

is being aided with laboratory flow measurements and nomographs.

The second, separation of grease grease at small orifices

under high pressure, makes mandatory the use of smooth, lowbleeding

greases; filled greases and complex calcium greases

with excess calcium acetate are beneficial for their antiwear and

extreme-pressure qualities but may separate and plug up

distribution systems under some conditions.

Food canneries present a special challenge to industrial

grease formulators. The strong American desire for safety and

sanitation may lead to the requirement for edible greases in

food-processing machinery. Fortunately, some soaps used in

greases are normal products of fat digestion in the body and

some purified petroleum and vegetable oils are non toxic as well

as being good lubricants. Selection of additives will require care

but there should be enough nontoxic ones to round out good

safe lubricating greases.

Dyes and Pigments

Merker and Singleterry stimulated investigation in this

colorful field with their 1952 patent on phthalocyanines as

gellants. Most such pigments when ground or milled into oils

form microcrystalline pastes rather than fine gels; they must

be present at 20–30% instead of the 5-15% concentration of good

soap gels. Their principal application is in polysiloxane oils for

greases to be used at maximum temperatures of 300-500 °F.

Examples with typical bearing lives are in Table II. Versilube

F-50 is a poly (methylchlorophenylsiloxane) and DC 550 is a poly

(methylphenylsiloxane) oil; F-50 lubricates steel on steel better

but DC 550 resists heat better. The profroxidative effect of metal

ions seems evident even in this elaborate setting–the calcium

sulfonate pigment gave lower bearing life than the nonmetallic

pigments.

Polymers

Polymers should be a natural as oil gellants. But some of

them–polybutenes, polyacrylates used as viscosity index

improvers –are too soluble. Others –nylon polyamides, textile

polyesters –are not soluble enough. Attempts to find the balance

point of the seesaw often yield greases that are too rubbery to

feed well into bearings. As a group, linear hydrocarbon polymers

have been most successful. Melting temperatures of greases

made from them increase with increasing isotacticity and other

structural changes as shown in Table III. On aging, they tend

to separate oil more than soap greases do, especially when the

oil is highly paraffinic. Partial saponification raises the melting

temperature and sometimes the gelling power of saponifiable

polymers such as olefinmaleic anhydride copolymers, alkyl

acrylate-acrylamide copolymers and alkylphenol-fatty acidformaldehyde

condensates. ethyl hydroxyethyl cellulose, may act as gellants. Some polymeric

synthetic oils can be partly cannibalized to gel themselves: poly

(methylsiloxanes) cross-linked at 400-550°F. and milled into fresh

polysiloxanes do this; chlorofluorocarbons can also be selfgelled.

Even highly cross-linked or otherwise undispersible

 

Inorganic Gellants

Even the most oleophobic material can gel oil if it can be

divided finely enough and if it can be distributed as a loosely

coherent network. Hard particles lose their abrasiveness when

they are less than about 1 ì wide; they are then smaller

than normal irregularities in metal bearing surfaces. The

melting temperature of inorganics is higher than the decomposition

temperature of the oil and far above the 300°F. ceiling of

90% of the applications. But, as Peterson, Accinelli and Bondi

put it. “In a plant, the part most difficult to lubricate determines

the minimum quality expected of a multipurpose lubricant”. The

most used inorganics, silica and clay, also cost little as chemical

entities (but it’s sometimes expensive to make them behave

properly in lubricants) and promote oxidation less than most soaps

OILS

Lubricating greases generally make use of oils already

available as lubricants or plasticizers. But since greases are used

in small amounts and often under severe or neglectful conditions

they intensify weaknesses of oils.

Naturally, petroleum oils are used for the great majority of

lubricating greases. Their useful temperature range is about 0-

300°F. Naphthenic oils are cheapest and easiest to gel but are

vulnerable to evaporation and oxidation. Paraffinic oils require

more gellant but last longer at high temperatures.

Industrial Lubricants

INTRODUCTION

General aspects of Industrial Lubricants

Industrial lubricants comprise a wide variety of products

which, depending on their application, differ widely in their

chemical and physical properties. With respect to the properties,

one can say that industrial lubricants involve all classes of

lubricants applied in practice. They include gases (mostly air),

various kinds of liquid products (mineral oils, animal and

vegetable oils, synthetic oils, water based fluids, etc.), greases

(simple soap greases, complex soap greases, greases with

pigments, minerals, polymers and other materials) and solid

lubricants. The latter comprise (i) inorganic compounds, e.g.

molybdenum disulphidc, boron nitride, tungsten disulphide and

many other chemicals and materials, (ii) solid organic compounds

and materials, e.g. phthalocyanine and tetrafluoroethylene, (iii)

chemical conversion coatings, and (iv) soft metals.

Furthermore, industrial lubricants make use of many additives

which comprise practically all the known additive classes

used in other types of lubricants and, additionally numerous

additives that have been developed specifically for industrial

lubricants, particularly for water based fluids. Thus, the importance

of additives in the formulation of industrial lubricants is

difficult to overestimate.

High speed and lightly loaded plain bearings need a low

viscosity plain mineral oil. The viscosity of the oil is essential

for ensuring hydrodynamic lubrication. Higher loadings and lower

speeds require higher viscosity oils. From the point of view of

the chemistry of lubricants, these oils are the simplest, being

composed of crude oil components. They mostly include isoparaffinic,

naphthenic, naphthenic-aromatic and to some extent,

aromatic hydrocarbons. All the ring structures are substituted

by alkyl chains. The viscosities of these hydro-carbons depend

on their molecular weights.

Apart from this simple lubrication of plain bearings, the

lubrication of tribological elements being rubbed under mixed

and/or boundary friction requires lubricants in the form of very

complex mixtures of appropriate mineral base oils and a number

of possible additives.

The selection of additives to formulaic industrial lubricants

involves consideration of the requirement of the equipment to

be lubricated or the metal process type of a metalworking operation.

Although hundreds of products have been used as industrial

lubricants and some other lubricants (e.g. engine oils) may be

applied in lubricating some industrial equipment, equipment

and lubricant manufacturers usually recommend lubricants for

particular applications.

In terms of quantities, industrial lubricants represent the

largest group (over 50%) among the lubricants. Lubricating oils

are the most important type of industrial lubricant.

BEARING LUBRICANTS

Bearings

Bearings are the most important machine elements used

in all branches of industrial machinery. They permit smooth, lowfriction

linear or rotary motion between two surfaces. Bearings

function by applying a sliding or roiling action. Bearings based

on sliding action are called plain bearings whereas those involving

rolling action are referred to as rolling-element bearings or

antifriction bearings.

Bearings can be lubricated by gases, liquid lubricants, greases,

or solid lubricants. The main function of the lubricant is to keep

the surfaces apart so that no interaction can occur thus reducing

friction and wear. Bearings lubricated by gases include aerodynamic

and aerostatic bearings (externally pressurised feed). Generally,

in externally pressurised bearings the solids are separated by a

fluid film supplied under pressure to the interface. The fluid may

be a liquid in which case the mode of lubrication is called

hydrostatic.

As the lubrication of plain bearings is more variable compared

to that of roiling-element bearings, the former are also

referred to by the lubricating principle involved. For example, a

specific class of plain bearings is the so-called full fluid-film

bearings, which include hydrodynamic (self-acting) and hydrostatic

(pressurised feed) bearings. In full fluid-film bearings the

load is supported by pressures within the separating fluid film

and there is no contact between the solids. In the hydro-dynamic

lubrication the pressure is developed by the relative motion and

the geometry of the system. The friction coefficient, f, in a plain

bearing is related to the lubricant dynamic viscosity, ç, the

bearing load, W and the sliding velocity, V, by the following

equation:

Refining of Petroleum

INTRODUCTION

Crude oil is the raw material for the manufacture of fuels

and lubricants. The combination of treatments performed on the

crude oil to obtain the desired products is called refining; the

treatments can be classified into separation operations, conversion

processes and chemical treating processes. The most

common separation operations employed are distillation, absorption,

adsorption, filtration and solvent extraction. Conversion

processes are those such as cracking, polymerization and

alkylation which change the chemical nature of the molecules

entering the process. Chemical treating processes either remove

undesirable constituents that are present in relatively small

amounts or convert them to other compounds whose presence

is not deleterious. How these methods are combined in a

particular refinery depends upon the characteristics and

composition of the crude oil and the relative amounts and specifications

of the desired products. Each refinery is individually

designed, with no two refineries exactly alike.

More than 7 million barrels of gasoline, fuel oil, lubricants

and other major products are manufactured every day in the

nation’s operating refineries.

Oil field emulsions are generally of the water-in-oil type.

Refinery emulsions are generally of the oil-in-water type.

Chemical treatment is more commonly applied to the oil field

emulsions and electrical treatment to the refinery emulsions.

Oil field emulsions are generally broken in the field.

POLYMERIZATION

The unsaturated refinery gases can be combined to form

larger molecules and increase further the yield of gasoline from

the crude oil. Commercially, the process is carried out catalytically

or thermally by a selective or nonselective process. In the

selective process the feed is a mixture of butenes (iso and

normal) and the product is a mixture of iso-octenes. In the nonselective

process the feed is a mixture of 2 to 4 carbon atom

olefins and the product is a mixture of isomeric 4 to 8 carbon

atom olefins.

Lubricating Oils

INTRODUCTION

A lubricant is used to reduce the coefficient of friction

between the rubbing surfaces in machinery, thereby reducing frictional

energy losses. The lubricant also prevents direct contact

of the rubbing surfaces since under proper conditions of lubrication

a film of the lubricant is maintained between these surfaces.

This prevents failure due to seizure and also reduces wear. The

frictional heat generated by the rubbing surfaces is removed by

the lubricant acting as a coolant or heat transfer medium. In

internal combustion engines the lubricant also seals the piston

and cylinder wall at the compression rings so that the high

pressure gases in the combustion chamber will not leak past

the rings and cause power losses. Briefly, the lubricant reduces

energy losses from friction, reduces wear, serves as a coolant

and may also seal. Most lubricating oils are derived from petroleum;

however, some synthetic lubricants are in use.

Essential properties of a lubricating oil are viscosity, viscosity-

temperature-pressure relations and oiliness. The changes

in these properties are minimized when the oil does not undergo

chemical change during use. Therefore, characteristics such as

the following are important: stability toward oxidation and other

chemical change, resistance to decomposition when exposed to

elevated temperatures and ability to resist emulsification. For

various applications special properties are important such as

detergency for severe operating conditions in internal combustion

engines or extreme pressure load-carrying properties for hypoid

gear lubrication.

SIGNIFICANCE OF VISCOSITY AND VISCOSITY INDEX

The most important property in selecting a lubricant for a

particular application is the viscosity. For a bearing operating

in the hydrodynamic region at given conditions of load and speed,

the viscosity of the oil at the film conditions determines the

point of operation on the ZN/P curve and the coefficient of friction.

This, in turn, determines the frictional power loss and heat

generation in the bearing and the oil flow rate through the

bearing. The viscosity of the oil at the film temperature should

be sufficient to maintain a fluid film, but not so high that frictional

losses and heat generation are excessive. A margin of safety

is desirable to insure that the fluid film is not squeezed out.

For oils exposed to oxidizing conditions and to high temperatures,

degradation of the oil is normally accompanied by an

increase in viscosity. Changes occurring in the oil under these

conditions can be followed by viscosity measurements.

 

Greases and Solid Lubricants

GREASES

1. Definition

For many years the ASTM defined grease as a “combination

of a petroleum product and a soap or mixture of soaps with or

without fillers, suitable for certain lubrication applications.”

Although this definition was generally accurate a few years ago,

it does not include many important products now being marketed

as greases. Among these are greases made from synthetic

lubricating oils and those made without soap by utilizing bentones

or silica gels as thickening agents. Recently the ASTM

revised its definition to include nonsoap thickeners. The current

definition is as follows: “Lubricating grease is a solid to semisolid

dispersion of a thickening agent in liquid lubricant. Other

ingredients imparting special properties may be included.”

2. Applications for Grease Lubrication

Greases are normally used under conditions of lubrication

for which oil is not as suitable or convenient. Greases perform

better than oils under conditions requiring:

Characteristics of Greases from Various Metallic Soaps

Metallic soaps are by far the most common thickening agents

used in manufacturing greases. The most widely used of these

are sodium, calcium, aluminum, barium and lithium soaps. These

metallic constituents have the greatest single influence upon the

properties of greases and characteristics of each are discussed

in the following paragraphs and summarized in Table 1.

Calcium soap greases. The waterproof nature of calcium

soap grease is its primary advantage. Because most of these

greases are stabilized with water, they cannot be used for any

length, of time above 160o F without separation of soap and oil.

The calcium soap fibers are very short and give the grease a

buttery texture. Calcium greases are widely used as cup and

pressure-gun greases for lubrication of plain bearings which

operate at normal temperatures and average loads, but they are

not suitable for use at very high pressures.


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