1、-_-_- - ABS TITLE*GNHFO BY 0653302 0003301 Ob0 w Notes on Heavy Fuel Oil 1984 Notes on Heavy Fuel Oil 1984 American Bureau of Shipping Incorporated by Act of the Legislature of The State of New York 1862 Copyright 1984 American Bureau of Shipping 65 Broadway New York, New York 10006, U.S.A. 1. 2. 3.
2、 4. 5. 6. ABS TITLE*GNHFO 84 065LLO2 0003303 933 Contents Introduction 1.1 Diesel P r Plants and Fuels Marine Fuel Oil Origins and the Influence of - Refinery Processes 2.1 Crude Oil Sources 2.2 Refinery Processes 2.3 Market Influences on Marine Fuel Quality Marine - Fuel Oil Properties and Characte
3、ristics and Their Impact 3.1 Marine Fuel Oil Characteristic Properties 3.2 Fuel Oil Contaminants Fuel Sampling and Analysis 4.1 Sampling Procedures 4.2 Shoreside Analysis 4.3 Shipboard Analysis 4.4 Fuel Specifications and Standards Shipboard Fuel Handling and Treatment for Diesel Engines 5.1 Marine
4、Diesel Oil Systems 5.2 Heavy Fuel Oil Systems 5.3 Operating Guidelines and Recommendations 5.4 Recommended Procedures for the Onboard Treatment of Problem Fuels Appendix Glossary and List of Abbreviations SECTION 1 Introduction 1.1 Diesel Power Plants and Fuels Shipowners and operators, with increas
5、ing frequency, are seeing their vessels bunkered with fuels which, as a mini- mum, have significantly increased the crews fuel handling and treatment workload; and, in the extreme, have caused catastrophic diesel engine failures. These problems are not limited to specific diesel engine types nor are
6、 they restricted to a narrow range of fuel grades. It is becoming apparent that no operator is immune. It also is evident that the future holds little prospect for improved quality. The increasing use of some poorer grades of crude oil as feed stock and more intensive refining practices have produce
7、d continued degradation in the quality of residual oils and blends, as well as some contamination of previously clean marine diesel oils (MDO). Concurrent with continued fuel quality degradation, diesel engine designers have been increasing the Mean Effective Pressures (M.E.P.) of engines in a never
8、-ending search for higher power outputs (per cylinder) and lower fuel consumption rates. The higher M.E.P.s result in higher piston ringlliner loadings which can accelerate bore wear rates when poor quality heavy fuel oils are burned. Because of its very small market share, the marine industry has l
9、ittle influence on world petroleum prices and refinery practices. Consequently, the ship operator must equip his ships with the necessary tools to cope with the escalating problem of degraded fuel quality. The diesels capability to burn worldwide commercial grades of marine fuel oils is dependent up
10、on the range of signifi- cant fuel characteristics and the level of contaminants in the fuel oil. As fuel grade and quality decrease, the impact on diesel engine operating reliability and economy will be strongly influenced by the ability of shipboard fuel systems to provide properly treated fuel. T
11、o adequately assess the influence of fuel.quality on the operation of diesel engines and their support systems, such as the fuel storage, transfer, and service systems, a basic working knowledge of fuel characteristics and their impact on the performance of diesel engines and shipboard fuel handling
12、 and treatment systems is required. It is the 1 intent of this document to provide the reader with this necessary overview including: % The influence of crude oil sources and various refining procedures on the ultimate quality of marine fuels as bunkered * The impact of marine fuel characteristic pr
13、operties and contaminants on diesel engine and support system operation * Fuel sampling and analysis techniques and laboratory and onboard test procedures for various marine fuel properties * A review and functional description of storage, treatment, transfer and service systems for diesel engines o
14、perated on marine diesel and heavy marine fuels * Typical components and/or subsystems available for the onboard treatment of various fuel properties which exceed specified levels 2 I t - _ _-_- ABS TITLE*GNHFO 84 W Ob51102 0003306 642 SECTION 2 - Marine Fuel Oil Origins and the Influence of Refiner
15、y Processes 2.1 Crude Oil Sources Petroleum products, in general, whether diesel oil, lubricating oil, light fuel oil or heavy fuel oil, are essentially composed of two major elements, carbon and hydrogen. The combination of these two elements is called a hydrocarbon. Its ultimate source is crude oi
16、l as found in its natural states in various geological formations throughout the world. Crude oil consists of a very broad spectrum of hydrocarbons ranging from very light, volatile gases to heavy residues. Residual fuels are, in effect, the heavy residues resulting from the refining process. The mo
17、re desired hydrocarbons and some less desirable ones are extracted from crude oil by the refining process. Similar processes are also used to reconstruct the less desirable hydrocarbon residues into forms that can meet current market demand. The hydrocarbons mostly found in marine fuel oils fall int
18、o four (4) main classes - paraffinic, aromatic, naphthenic. and olefinic. These basic compound types are further categorized below. Paraffinic hydrocarbons (C“(N+) are lower in specific gravity than aromatic hydrocarbons of the same boiling point, while naphthenic and olefinic compounds are intermed
19、iate in density. Their resistance to chemical change or oxidation is very good. These hydrocarbons are clean burning, and thus are desirable in distillates such as gas oil or diesel oil. - Aromatic hydrocarbons (CNH(cfI-6) p ossess a much higher specific gravity than the o er three classes. Aromatic
20、s are very stable under heat and are chemically active to a moderate degree. The aromatic compounds contain a higher proportion of carbon than the other hydrocarbon types. Due to this characteristic, they have a tendency to smoke, which somewhat limits their use in diesel engines. Naphthenic hydroca
21、rbons (CNH2N-ring type) are extremely stable, cyclo-ring compounds and in many cases have more stability than the paraffins. These hydrocarbons are more commonly found in heavy marine fuel oils rather than distillate oils. 3 r ABS TITLE*GNHFO 84 Ob5L102 O003307 589 H Olefinic hydrocarbons (C Hs-stra
22、ight chain) are more chemically active than t ! e other three classes of hydrocarbns. Olefins are subject to oxidation or polymerization, forming gums. Olefins are not present in large amounts in straight-run distillates, but are found in large quantities in cracked marine fuel oils. While crude oil
23、 is the source of the various hydrocarbon compounds in marine fuels from which thermal energy is produced during combustion in a diesel engine, it also is the source of many undesirable properties and characteristics which are carried over in the refining process to the resultant petroleum product.
24、Table 2.1 lists the principal contaminants which are related to the source of the crude oil. These contaminants will be concentrated in heavy fuel oils which have been subjected to intensive refining. TABLE 2.1 Crude Source Related Properties and Characteristics * Sulfur * Pour point * Ash content V
25、anadium, Nickel, etc. In addition to the contaminants, pour point (a property) is directly related to the source of the crude oil. Normally, the level of a particular property can be utilized totrace the geographical source of a crude oil from which a given product is refined. As an example, Venezue
26、lan crude is noted for its high (oil soluble) ash (vanadium, nickel, silica, etc.) content, whereas crude oils from the Middle East Region are generally noted as being low in sulfur content. Table 2.2 presents a breakdown of some typical sources of crude oil by geographical location while identifyin
27、g product yield levels and various other properties. The influence of these source related characteristics as they appear in refined products on marine diesel engine operation will be discussed in detail in Section 3.0. 2.2 Refinery Processes Ultimately marine fuel oil quality is influenced by the w
28、orldwide refinery mix, the variation in crude oil quality available, and the demand patterns for middle distillate and residual fuels. Table 2.3 a number of the properties and 4 _ ABS TITLE*GNHFO 84 Ob53302 0003308 415 TABLE 2.2 Effect of Crude Source on Various Product Yields and Characteristics Hi
29、gh Gravity Low Gravity Medium Sulfur Crude Oil Sweet Crude Sweet Crude Light (North Sea Light) (North Sea Medium) Murban Crude Oil Gravity (DI) Sulfur (WtA) Pour Point (*FI Sulfur Range(Wt%) C4 and Lighter Yield Light NaphthaC5-2000F) Yield(VoU) Gravity( OXPI) Sulfur(Wt%) Naphchenes (VolX) Aromatics
30、 (Vol%) Paraffins(Vo1X) Octane Xo.(RON Clear) Heavy Naphtha(200-400F) Yield (VolX) Gravity( OXPI) Sulfur (WtX) Naphthenes(Vo1X) Aromatics (Vou) Paraffins(VoL2) Kerosene 400-5-OF 1 Yield (Vol%) Gravity( .MI) Sulfur(WtX) Pour Point (OF) Distillate(500-650F) Yield (Vol%) Gravity( OXPI) Sulfur (Wt4) Cet
31、ane No. ?our ?oint (OF) Viscosity ( 100F) Heavy Gas Oil Yield(Vo1A) Gravity( DI) Sulfur(Wt4) Pour Point (OF) Viscosity (e210.F) Residual Oil Yield (VolX) Gravity (OXPI) Sulfur(WtX) Pour Point (OF) Viscosity(210F) Total (X) 37.6 0.13 5 0-0.5 2.2 6.4 79.9 o. 0002 21.5 1.5 77.0 78 22.0 53.6 55 11 34 O.
32、 003 15.4 40.2 0.03 -70 23.2 33.2 51 20 40.3 SUS O. 13 23.1 25.4 0.21 105 48.1 SUS 7.7 11.8 0.39 - 2,030 SUS 100.00 26.0 0.23 -5 0-0.5 0.7 2.1 79.2 0.001 24 3 73 80 8.7 50.1 58.5 14.0 27.5 0.01 14.7 34 4 0.063 -70 29.7 27.5 40.0 44.6 SUS O. 18 -15 31.3 19.7 80 53.1 SUS 0.31 12.8 10.1 0.48 - 3,690 SU
33、S 100.00 39.4 +5 0.51-1 .O 1.8 0.74 6.78 0.012 82.2 - - 69 21.2 56.9 20 17 63 0.013 16.14 45.4 0.058 - 10.4 37.8 0.47 54 O 4.2 cst 9.24 1.06 33.6 41 - 34.5 22.6 1.49 a5 - 100.00 Heavy (North Slope) 26.8 1.0 -5 O. 51-1. O 1.8 5.8 68.3 0.01 30.0 48.8 65 - 12.6 49.7 56.4 43.6 0.02 12.3 37.4 0.20 I 12.1
34、 31.3 47 0.56 - I- 14.7 25.8 55 0.90 77 SUS 100.F 40.7 13.0 1.74 475 391 SUS 100.00 High Sulfur Crude Oil (Arabian)(Venezuelan) Light Heavy 33.4 1.80 1.01. -30 1.7 9.0 78.5 0.024 10.4 2.4 87.2 54.7 8.4 59.6 0.027 18.2 12.3 69.5 15.0 38.5 0.094 - 19.8 37.1 1.05 O 3.28 cSt I- * 46.1 17.6 3.08 40 21 cs
35、t 100.00 16.8 2.40 l.W 0.4 -10 2.5 65.0 51.9 4.7 43.4 - - 6.0 49.0 58.5 13.9 27.6 - 5.0 36.4 0.48 -80 15.5 - 0.99 - - - * 70.6 3.0 - 60 - 100.00 5 ABS TITLE*GNHFO BY ObLiiiIO 0003309 35l1 M characteristics associated with marine fuels which are strongly influenced by the refinery processes utilized.
36、 TABLE 2.3 Refining Process Related Characteristics and Properties Specific Gravity Viscosity Conradson Carbon Residue-(CCR)/Asphaltenes Sediment Water Flash point Compatibility Sodium The four (4) most common types of refining methods currently utilized, a brief description of the resultant product
37、 characteristics, and a discussion of the influence of fuel quality on refinery-based blending of heavier and lighter products to produce various grades of intermediate fuel oils are presented in the following paragraphs. - Atmospheric Distillation: This is the oldest and most common refining proces
38、s and consists of boiling crude oil at atmospheric pressure in a fractionating tower up to temperatures not exceeding 371 degrees Centigrade. Beyond this temperature, heavy hydrocarbons begin to crack and materials form which are not desired at this point in the process. As the various constituents
39、of the crude oil vaporize at different rates, the lighter, more volatile gases rise high in the tower before condensing and being collected. The heavier less volatile gases condense and are collected lower in the fractionating tower. Figure 2.1 presents a simplified schematic of the atmospheric dist
40、illation process. Straight-run residual fuels obtained from atmospheric distillation were the primary heavy fuels used in marine diesels in the 19501s, 60s and early 70s. They provided clean combustion, ease of fuel handling and treatment, storage stability and compatability. Also, since specific gr
41、avities were usually well below 0.980, the separation of water and sediment was well within the capability of installed shipboard fuel oil purification systems. Vacuum Distillation: This process is essentially a modified version of the straight-run method of distillation. Very simply, when the press
42、ure in the distillation/condensation tower is reduced below atmospheric (partial vacuum), the residual fuel from an atmospheric process will yield 6 - _ - _ ABS TITLE*GNHFO 84 Ob53302 0003310 073 additional heavy distillates and will further concentrate impurities and carbon in its residual oil or v
43、acuum bottoms. Vacuum distillers produce residual oils that are feed stocks for other refinery processes. They are not generally available in the marine fuel marketplace due to their very high viscosity. As shown in Figure 2.2, vacuum distillation bottoms can be further refined by the use of a secon
44、dary process such as viscosity breaking. In this procedure, the feed stock, vacuum bottoms, is heated to a higher temperature and pressure for cracking, although not as high as in the thermal cracking process (described later). Simplistically, the high viscosity feed stock is broken down to a residu
45、um which is considerably lower in viscosity than the original feed stock. While this product can be utilized as a heavy marine fuel with little or no blending back with a lighter distillate, it has increased specific gravity, and less desirable characteristics, such as high Conradson carbon and high
46、 asphaltenes. It is usually less stable and less compatible with other residuals than the original feed stock. These characteristics can present problems for marine diesel power plant and fuel treatment system operation. - Thermal Cracking: This procedure is shown in Figure 2.3. In this process the
47、feed stock, straight-run residual, is heated to high pressure and temperature in the reaction chamber. The heavy, large, long chain oil molecules of the residual fuel are cracked or broken, producing both short chain and additional long chain molecules. These cracked products are then vaporized in t
48、he flash chamber and flow to the fractionating tower where they are condensed at different levels to the products shown in Figure 2.3. Thermal cracking increases the yield of high quality distillate fuels from crude oil, and reduces the yield of residual fuel. Like vis-breaking, this process also yi
49、elds residual fuels with a high specific gravity and a high sulfur, vanadium, Conradson carbon/asphaltenes content together with poorer stability and compatibility. The impact ofthis process is to produce a cracked residual fuel which is more difficult to burn, and has alower calorific value (on weight basis), and a higher sludge and impurities content, all of which can result in increased engine downtime, maintenance, and repair costs. Catalytic Cracking: This process is a variation of thermal cracking. It is shown diagram
