Marine engines fuels and lubricants

MARINE ENGINES FUELS AND LUBRICANTS by Claude OUVRIER-BUFFET HEAD OF THE MARINE LUBRICANT TECHNICAL DEPARTMENT SOCIETE DES LUBRIFIANTS ELF AQUITAINE THE AUTHOR: Claude OUVRIER-BUFFET qualified as a chemical engineer at Lille Chemistry Academy (1969) and graduated from the Ecole Nationale Superieure du Petrole et des Moteurs, Institut Fran9ais du Petrole (1970) He joined the ELF AQUITAINE GROUP in 1972 as Research and Development engineer engaged in the formulation of automotive and industrial lubricants In 1978, he took over ELF LUB MARINE's Research and Development at the ELF Research Center In 1988, he was appointed Head of the Marine Lubricant Technical Department at the Societe des Lubrifiants Elf Aquitaine in Paris He is the author of numerous papers on lubricants and lubrication of marine engines published in specialized reviews and in international conferences He gives a course of lectures on lubrication of marine engines at the Ecole Nationale Superieure du Petrole et des Moteurs, France ACKNOWLEDGEMENTS: The Author gratefully acknowledges the help and advice given by engine and equipment manufacturers in providing materials and illustrations and checking of the subject matter Also to shipowners' technical departments for their helpful suggestions The Author would also like to express thanks to his colleagues and friends from ELF and from LUB MARINE partners all over the world Special thanks must be given to the Marine department team from the ELF Research Center in LYON (FRANCE) CONTENTS INTRODUCTION MAIN TRENDS IN INTERNATIONAL SEABORNE TRADE 11 MERCHANT VESSELS 21 THE REFINING INDUSTRY AROUND THE WORLD 61 FUELS 69 FUEL TREATMENT AND PREPARATION ON BOARD SHIPS 87 EFFECT OF FUEL OIL QUALITY ON ENGINE PERFORMANCE 99 PROPULSION 107 MARINE DIESEL ENGINES 113 MARINE ENGINE LUBRICANTS 147 LABORATORY DEVELOPMENT OF MARINE ENGINE LUBRICANTS 177 BENCH TESTS AND FIELD SERVICE TESTS 199 LUBRICANT STORAGE AND TREATMENT - APPLICATION PROBLEMS 213 TURBINE OILS 225 OTHER LUBRICANTS 229 IN - SERVICE LUBRICANT ANALYSIS 237 APPENDICES SHIP TONNAGES 245 SAE J300 VISCOSITY GRADES 246 BASE STOCK OILS 247 ADDITIVES 251 MARINE LUBRICANTS 253 ELF LUBRICANTS 254 INTRODUCTION Lubricant associated problems encountered on board merchant ships cannot be discussed without first considering other subjects in the field that not at first glance seem to have any direct connection to the subject The technology of marine engines and on board equipment is constantly evolving The ships on which they are installed are dependent on technological advances, and are subject to the changing economic requirements of profitability and safety and environmental protection which are more and more restraining The properties and performance of lubricants are determined by the in-service conditions that must not be allowed to affect it Then lubricants must continually evolve in order to adapt to new constraints Good engine operation is essential not only for the ship to complete its task on schedule and under the best possible economic conditions, but also for the safety of crew and equipment In this context, lubricants and fuels play an essential role Good engine operation depends on six main parameters: Engine operating conditions economic considerations; linked to trade activity,type of ship and Engine and auxiliary machinery maintenance; Fuel quality linked to the world refining industry activities and petroleum product consumption; Fuel preparation and treatement; Lubricant quality linked to the type of engine, its operating and the fuel used; conditions Lubricant purification treatment Lubrication of all other important equipment on ships has also to be studied and selected on a case by case basis with the same care as for the main engines It also seems interesting to describe the economical context in which the men who design, develop and sell "marine" lubricants operate This will give an overall picture and better understanding of certain requirements of this particular economic sector that is not always appreciated,but is indispensable to international trade MAIN TRENDS IN INTERNATIONAL SEABORNE TRADE GENERAL CRUDE OIL AND PETROLEUM PRODUCTS DRY BULK SEABORNE TRADE 111.1 111.2 111.3 IliA 111.5 111.6 IRON ORE COAL GRAIN BAUXITE/ ALU M INA PHOSPHATE OTHER GENERAL CARGO PASSENGER TRANSPORT FISHING CONCLUSIONS GENERAL Seaborne trade is of course directly linked to trade between different countries and reflects the health of the world economy This means of trading experienced intense activity and tremendous growth after World War II, as trade between countries continued to grow with the increasing industrialization of wealthier nations This expansion continued until 1974, when 3250 million tonnes of various products were transported by sea Growth between 1964 and 1974 averaged 9% per year A sharp fall caused by the oil crisis was followed by almost as sharp an upswing The greatest amount of products ever transported was 3700 million tonnes in 1979 There was another recession lasting until 1983, which was in turn followed by a slight recovery and stabilization Real signs of expansion have only been visible since 1988 and it was only in 1989 that the largest figure ever met of more than 3900 million tonnes of products transported by sea was reached (Fig 1) After this rapid growth for such a long period of time (1964-1974), adaptation to a sudden crisis could not be other than difficult As in all sectors, supply and demand have to be adjusted The tonnage of ships available for the merchant marine industry is no exception Movement of crude oil and petroleum products, raw materials, and manufactured goods depends on the economic health of the countries involved and are thus influenced by political and economic factors at any given moment The conditions for growth of imports and exports between countries may be extremely different and variable from one year to the next But a ship cannot be designed or built in a few months A 550,000-tonne oil tanker which was ordered in 1971 and tested at sea in 1975 when the economic crisis was already well underway is a prime example of this To build the appropriate ships, shipowners must not only be able to forecast future markets, but also be able to finance these ships CRUDE OIL AND PETROLEUM PRODUCTS As a raw material necessary to the growth of modern economies and usually transported over large distances, oil has always occupied a predominant position in international seaborne trade Growth was continuous until 1973, when 1841 million tonnes of oil were transported by sea After a sharp drop followed by just as sharp a recovery, another fall occurred until 1983, followed in turn by stabilization at close to 1250 million tonnes A new tendancy to expansion is really visible since 1988 In 1989,1470 million tonnes of crude oil and petroleum products were transported by sea (Fig 1) In 1973, oil accounted for as much as 60% of seaborne trade; Although today its share is only around 37%, it is still the leading product transported The tonnage of petroleum products (excluding crude oil) transported has varied lIittle in quantity, but its percentage has increased considerably It rose from 15.6% in 1975 to 23.1 % in 1989.Because of the startup of refineries in producing countries,this tonnage is becoming more and more important since these last years (Fig 2) For political, logistical and geographical reasons, the share of different suppliers from a given country may vary from one year to the next Price and exchange rate considerations may also influence this choice There are no simple solutions, and changes in trade patterns are accompanied by constant changes in maritime transport The most significant example in this area is the size of oil tankers which will be discussed later The average distance crude oil is shipped has decreased from 7200 miles in the mid-70s to some 4700 miles currently With regard France, this distance has dropped from 9,000 miles in 1976 to less than 3,000 miles in 1989 In 1989, the United States was still the world's largest importer of crude oil and petroleum products (397 Mt), followed by Japan (245 Mt) Western Europe imported 477 Mt, much less than the 1979 figure (675 Mt) The Soviet Union is one of the few industrialized countries that is independent in terms of oil supply In 1989, it exported 20% of its crude oil production and 10% of its refined product production The U.S.S.R is the world's second-ranked oil exporter, after Saudi Arabia DRY BULK SEABORNE TRADE 111.1IRON ORE Iron ore is the predominant dry bulk commodity in world seaborne trade Trade in this raw material is directly linked to the economic health of industrialized countries This explains the abrupt variations experienced in the past, which may occur again In 1989, iron ore accounted for 16% of dry bulk seaborne trade with 357 Mt in excess of 38 Mt compared to 1987 and the largest figure ever met (Fig 3) Six major exporting countries provided 90% of this tonnage: Brazil (100 Mt), Australia (100 Mt), Canada (25 Mt), India, Sweden and Liberia The leading importer is Japan with 115 Mt This traffic is characterized by long transportation distances (5400 miles approximately) The trend toward ever larger ships is continuing 70% of the tonnage was transported by ships over 100,000 dwt; a third of the bulk carrier fleet was used for this purpose Short-haul trades in Europe and Asia were served by ships in the 40,000 to 80,000 dwt range In the years ahead, very large ore carriers (over 300,000 dwt) should account for an increasingly larger share of long-haul trade (Brazil, Europe, Japan) The determination of several characteristics by either standard or non-standard methods gives a realistic picture of the situation and enables correct conclusions to be drawn The analyses to be performed on a sample of oil in service depend on the type of lubricant in use Generally speaking, for an engine oil, the following characteristics are determined: - viscosity, - water content, - alkalinity reserve, - insoluble product content, - wear metal content, - flash point, - spot test The methods used for these examinations are usually standardized ASTM, Ip, DIN, etc methods unless non-standard methods are shorter and easier To be able to draw the maximum information from an analysis, two requirements must be met: - the sample must be representative of the system oil; - speed with which the conclusions of an analysis reach the ship The latter is extremely important but is not always easy to carry out: a) It is very difficult to overcome various delays in forwarding samples to laboratory Nevertheless, the reduction in the last few years of the amount of samples needed for analyses has considerably improved the ease of mailing (100 ml is adequate where in the past 500 ml or litre was required) b) Laboratories have invested significantly in automation, which has enabled analysis time to be considerably reduced along with the printing and transmission of results These installations can work 24 hours a day and are generally equipped with a plasma torch that can give a standard readout of the wear-metal content of the lubricant such as copper, lead, iron, zinc) tin, aluminum, silicium All these analyses are stored in computer databanks and are of considerable assistance to researchers who can much easier follow the evolution of a given lubricant in different applications The system developed by Elf has been given the name DIAGOMAR It guarantees analysis results 48 hours after reception of the lubricant sample at the laboratory This result is transmitted to the engineering department of the shipowner or if the owner agrees directly to the ship by telex The use of test kit methods is increasing They enable simplified, fast analyses to be performed onboard ships by engineers Extremely rapid monitoring of some lubricant characteristics and immediate diagnosis in the event of serious operating problems are also possible These analyses not replace laboratory analyses, which are more accurate Elf first developed a portable lubricant test kit 15 years ago With this kit, which enables the engineer to quickly determine the basic characteristics of the lubricant, very rapid diagnosis can be established onboard the ship itself This minilab enables the following to be measured: - water content (and nature); - insoluble content by photometry, - viscosity, -TBN, and to perform a spot test Any obvious abnormality is detected immediately In the event of doubt, lubricant sample must be sent to an onshore lab as soon as possible a A final very important point concerns the interpretation of results and acceptable limit values To be able to correctly interpret the results of in-service analyses, it must be possible to monitor the values of the main characteristics chronologically in order to plot the curves from which the evolution can be extrapolated Any significant deviation from these curves indicates an abnormality The need for such monitoring over time must be emphasized performed outside this context is very difficult to interpret Any analysis However, attempts must be made to define maximum and minimum alarm values for the various characteristics that have been cited This is undoubtedly the most difficult task A survey of the main marine engine manufacturer opinions performed in the scope of CEC working group CL 30 was presented at CIMAC in June 1983 (Interactions between the medium-speed engine and its fuel and lubricants, G C Fleischack) Opinions can differ on some points as shown below: a) TBN: generally, marine engine manufacturers set a lower limit close to 50% of the new oil value (0.5 times or 0.4 times) or refer to the fuel sulphur content (for example, TBN greater than times the sulphur content) b) Pentane insolubles: some manufacturers accept up to 5% insolubles, accept no more than 0.5 or % while others c) Water content: the acceptable content varies from 0.5 to 2% depending upon the manufacturer d) Viscosity: generally, a change equivalent to one SAE grade is tolerated While again emphasizing that the rate of change of characteristics is more important than the value itself, we recommend the use of values in Table 38 in the event that an engine manufacturer has no specific recommendations These values must be interpreted as an alarm signal requiring the engineer to pay particular attention and monitor events It is recommended that a complete analysis of the lubricant in service be carried out in the weeks that follow It should also be emphasized that the interpretation of results of an analysis calls for accurate knowledge of all operating incidents affecting the engine For example: a % water content in a lubricant for a few hours is less dangerous than 0.5% for thousands of hours TABLE 38 : ELF WARNING LIMITS FOR USED MARINE DIESEL ENGINE OILS THESE VALUES SHOULD ONLY BE TAKEN AS AN " ALARM SIGNAL" IF ANY ONE OF THESE LIMITS ARE REACHED, EXTREME CAUTION SHOULD BE EXERCISED BY SHIP STAFF ADDITIONAL REPRESENTATIVE SAMPLE SHOULD BE ANALYSED OVER THE FOLLOWING WEEKS SHIP TONNAGES The tonnage of a ship is the expression either of a volume or of a weight allocated for transporting cargo or passengers VOLUME GROSS TONNAGE - NET TONNAGE The gross tonnage is broadly the capacity in cubic feet of the spaces within the hull and of the enclosed spaces above the deck available for cargo, stores, fuel, passengers and crew divided by 100 (i.e gross registrated ton = 100 Cuft = 2.83 m3) The net tonnage is derived by taking the gross tonnage and deducting spaces used for the accomodation of the master, officers, crew, navigation and propelling machinery These two units indicate the overall size of a ship and is used for shipbuilding, regulations and statistics WEIGHT The DEADWEIGHT is the weight in tons of cargo, stores, fuel, passengers and crew carried by the ship when loaded at her maximum summer loadline or weight of water displaced loaded minus weight of water displaced light The unit used is usually the imperial ton of 1,015 kg SAE J300 VISCOSITY GRADES (1987) BASE STOCK OILS Refining is the process whereby the various components of crude oil are separated to manufacture products suitable for the application chosen Base stock oils, commonly known as base stocks, have always had a special place among these products, since they are highly refined products requiring sophisticated and therefore expensive treatment Their production products is accompanied by the generation of a large amount of by- The tonnage of base stock is very low in relation to other petroleum products; it is estimated at 1% of the crude oil consumed Base stocks are cuts of narrow distillation ranges, usually defined by the following main characteristics: - viscosity, - viscosity index that enables viscosity temperature to be characterized; variations in accordance with - pour point, - flash point, - Conradson residue, - acid number Base stocks are traditionally defined by: - a number indicating viscosity in SSU at 100°F, with the exception of heavy base oils called Bright Stock; - a term indicating the viscosity index value; the terms generally used are "neutral" if it is high, whatever the viscosity, "pale" if it is very low with a low or high viscosity, and "red" if it is low with a high viscosity; - a term indicating the treatment applied, usually "solvent", indicating that the oil has undergone aromatic extraction using a solvent Other older terms are still commonly used such as Spindle Oil, Machine Oil, Cylinder Oil, Engine Oil, etc or specific terms to certain companies such as HVI, MVI, etc The main base stocks and their characteristics are given in Table 39 A technically and economically suitable crude is required for the manufacture of base stocks The crude is selected in accordance with its quality and stock oil yield Some crudes, for example those with too high an aromatic content (Nigeria, Indonesia), are not suitable for the manufacture of base stocks The choice of crude is thus very important Three crudes are mainly used: Arabian Light, Kuwait and Kirkuk Other crudes can also be used :North Sea, Algerian, etc The investment in an oil production chain is very high The following are needed to obtain quality products: - narrow cut fractions (vacuum distillation), removal of the heaviest products (deasphalting), aromatic product removal (solvent extraction); paraffin removal (dewaxing), stabilization of unsaturated compounds (hydrogenation) Each of these goals is obtained using a specific treatment Production of base stock oils is very difficult; each characteristic obtained must be preserved during the next treatment, since it is very difficult to rectify an unsatisfactory characteristic at the final stage VACUUM DISTilLATION Vacuum distillation of topping residues enables a heavy gas oil, three or four distillates and a residue to be separated The latter products are suitable for lubricant base stocks For example, three base stocks such as 150 N, 250 Nand 500 N from three distillates and one or two bright stocks from the residue PROPANE DEASPHAlTING Once the asphalt it contains has been removed, the residue obtained under vacuum can be used to manufacture a base stock oil with a high viscosity (bright stock) This removal is performed under pressure (35 bar) by a liquid/liquid extraction process using propane as a solvent The product obtained is called deasphalted oil The main characteristics sought are viscosity and colour These units have a yield of 25 to 45% depending upon the type of crude and the quality of the bright stock sought (higher or lower Conradson residue value) TABLE 39 : BASE STOCK OILS ( FRENCH SPECIFICATIONS) AROMATIC HYDROCARBON EXTRACTION Aromatic hydrocarbons have a low viscosity index, are relatively volatile and tend to high oxidation They must be removed as much as is possible from lubricant base stocks This is performed in a liquid/liquid extraction unit using usually furfural The unit processes distillates from vacuum distillation and deasphalted oil The yield is 45 to 80% depending upon the crude processed and the value of the desired viscosity index (Before World War II, aromatics were removed using sulphuric acid.) SOLVENT DEWAXING Long chain paraffins whose freezing point is too high for use as a lubricant must be eliminated This takes place by means of low temperature filtering (- 20°C) using a solvent The solvent most commonly used is a mixture of methyl ethylketone and toluene The yield is 45 to 80% depending upon the type of crude and the pour point of the final product sought This is far and away the most expensive unit in the oil production chain FINISHING TREATMENT Unsaturated products must be eliminated to obtain the best possible oxidation stability and to stabilize the product so that it does not change over time This is the role of the finishing treatment Until around 1970, the standard finishing treatment was acid processing followed by bleaching earth treatment Modern processes use a slight catalytic hydrogenation permitting continuous operation with a yield of close to 100% Cobalt/molybdenum catalysts are used at pressures of 30 to 40 bar MODERN BASE OIL PRODUCTION PROCEDURES Hydrogenation under strictly controlled conditions permits total hydrogenation of aromatic products while removing sulphur products This technique is used in modern oil production processes and eliminates the need for solvent extraction of aromatics Depending upon the stringency of the hydrogenation conditions, the final products obtained are either base stocks with viscosity indices close to 100 or oils with a much higher viscosity index that can be used for multigrade oils The general diagram of the oil production chain is modified, since this hydrogenation treatment is performed directly on the vacuum distillate or deasphalted residue before the other treatments The final treatment is distillation enabling the various grades sought to be obtained ADDITIVES Many families of additives are available on the market, each with a very specific function By combining these additives, it is possible to obtain the final formulation of the lubricant with properties that base oils not have or that need to be improved for final application This combination is called a "package" Additives are very sophisticated chemical products that are usually very reactive Many interactions exist The skill of the lubricant developer and producer lies in choosing and blending them to obtain the desired result, taking maximum advantage of existing synergies and avoiding opposing synergies and secondary problems The main additive families are given below - Detergent additives: their function is to reduce deposits and prevent their formation in the engine, especially in the region of high temperature Their molecule contains a metalloid; the one most widely used in marine applications is calcium - Overbased detergent additives: the detergents are also able to neutralize acid products generated during combustion - Dispersant additives: their function is to maintain deposits in suspension to prevent their accumulation, in particular in the relatively colder areas of the engine These are organic additives and are known as "ash less" additives - Antioxidant additives: their function is to prevent and delay propagation of oxidation reactions Many types exist depending in particular on the temperature at which the lubricant can operate without immediate deterioration - Anticorrosive additives: their function is to protect ferrous metals from any external attack - Antirust additives: their function is to protect the metal parts of the engine from corrosion in the event of accidental ingress of water - Antiwear and extreme - pressure additives: their function is to strengthen the oil film, or even replace it when pressure and speed conditions are such that it is destroyed - Pour point depressant additives: their function is to lower the initial pour point of the base stock oil resulting from the refining process in order to provide a greater safety margin - Antifoam additives: their function is to prevent the formation of foam caused by the mixing of air and oil - Viscosity index improver: their function is to decrease variations depending on temperature variations viscosity Many products are available in each of these categories The main companies developing and supplying additives are Adibis, Amoco, Ethyl, Lubrizol, Oronite, Paramins, Shell Chemicals and Texaco MARINE LUBRICANTS No accurate statistics marine applications are available on the world tonnage of lubricants used for Current estimates are around 1,000,000 tons excluding lubricants for fishing fleets The breakdown of grades is the following: - cylinder lubricants crankcase system lubricants medium-speed engine lubricants other lubricants Currently, the geographic distribution - 35 % 20% 38% 7% is thought to be: Europe 45% North America 20% South America 6% Asia 28% the Middle East 1% Forecasts for coming years predict slight growth of 2% per year It should be noted that, following promotion of Asian ports for ease of bunkering and repairs, the growth should be somewhat stronger in these countries ELF LUB MARINE LUBRICANTS SYSTEM OIL TURBINE OILS ATLANTA MARINE 30 TURBINE T68 TURBINE T1 00 ALKALINE SYSTEM OIL HYDRAULIC OILS ATLANTA MARINE 03005 VISGA VISGA VISGA VISGA VISGA VISGA VISGA CYLINDER OILS TALUSIA TALUSIA TALUSIA TALUSIA XT XT XT XT 40 70 85 100 15 22 32 46 68 100 150 AURELIA 3020 AND AURELIA 4020 GEAR OILS EPONA Z 68 EPONA Z1 00 EPONA Z150 EPONA Z 220 EPONA Z 320 EPONA Z 460 EPONA SA 220 AURELIA 3030 AND AURELIA 4030 REFRIGERATING OILS AURELIA XT 3040 AND AURELIA XT 4040 FRIGA F 68 PRIMERIA SG 100 MEDIUM / HIGH SPEED ENGINE OILS COMPRESSOR DISOLA FP 30 AND DISOLA FP 40 PRIMERIA SG 100 PRIMERIA SG 150 MEDIUM SPEED ENGINE OILS DISOLA M 3015 AND DISOLA M 4015 OILS DISOLA DO 30 AND DISOLA DO 40 PRIMERIA LPG 150 DISOLA MT 30 AND DISOLA MT 40 HEAT TRANSFER OILS DISOLA W THERMELF ETA 32 THERMELF ETA 46 MISCELLANEOUS OILS GREASES SARELF ABS CYLELF 1000 POLYTELIS 460 EPEXA EPEXA M02 CARDREXA DC Conception - Realisation ARCOTEC (1) 46 71 04 44 IMPRESSION - FINITION Achcve d'imprimcr en fevrier 1992 N" d'edition 16032 / N" d'impression L 39683 Depot legal fevrier 1992 Imprime en France ... numerous papers on lubricants and lubrication of marine engines published in specialized reviews and in international conferences He gives a course of lectures on lubrication of marine engines at the... THE WORLD 61 FUELS 69 FUEL TREATMENT AND PREPARATION ON BOARD SHIPS 87 EFFECT OF FUEL OIL QUALITY ON ENGINE PERFORMANCE 99 PROPULSION 107 MARINE DIESEL ENGINES 113 MARINE ENGINE LUBRICANTS 147... formulation of automotive and industrial lubricants In 1978, he took over ELF LUB MARINE' s Research and Development at the ELF Research Center In 1988, he was appointed Head of the Marine Lubricant Technical