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Energy & Fuels 2003, 17, 444-449
The Relationship between the Base Extractable Species Found in Middle Distillate Fuel and Lubricity Janet M. Hughes,*,†,‡ George W. Mushrush,§,| and Dennis R. Hardy⊥ Geo-Centers, Inc., Lanham, Maryland 20706, Science Department, West Springfield High School, Springfield, Virginia 22152, Material Chemistry Branch, Code 6123, Naval Research Laboratory, Washington, D.C. 20375-5342, Chemistry Department, George Mason University, Fairfax, Virginia 22030-4444, and Navy Technology Center for Safety and Survivability, Code 6180, Naval Research Laboratory, Washington, D.C. 20375-5342 Received December 4, 2001
The compositional changes a diesel fuel undergoes during hydrotreating were investigated, specifically in relation to the changes in natural lubricity components. A unique set of six diesel fuels from the United States, England, Israel, and Spain were hydrotreated to four different levels of sulfur and aromatic content. Three different ASTM methods were used to determine the lubricity of these samples. These tests showed that the lubricity of the fuels was severely impacted by the hydrotreating process. A chemical test was developed that employed a base extraction followed by GC analysis that positively correlated with the ASTM tests. Additionally, GC/MS was employed to determine the major classes of compounds that are responsible for a fuel’s inherent lubricity. The samples were aged at ambient conditions for two years as well as undergoing accelerated aging experiments. There appears to be a fuel dependent relationship between aging and compositional changes that affords a fuel its lubricity.
Introduction The present research concentrated on the study of U. S. Naval diesel fuel (MIL-F-16884J), also referred to as NATO F-76, Table 1.1 This military grade fuel differs somewhat from the American Society for Testing and Materials (ASTM) specification for diesel fuel oils. Table 1 shows some properties defined by both military and ASTM specifications for the various types of diesel fuels.2 The fuel samples were from four different countries, the United States, Israel, Great Britain, and Spain. Five of the fuels were NATO F-76 and the other a U.S. reference no. 2 diesel fuel. The other two U.S. fuels were from a West Coast and a Gulf Coast refinery and will be referred to as USA West Coast and USA Gulf Coast, respectively. The effect of refining severity on the lubricity of fuels was investigated. All hydrotreating and ASTM lubricity testing was carried out at SwRI.3 This * Corresponding author. West Springfield High School, Science Department, 6100 Rolling Road, Springfield, VA 22152. E-mail:
[email protected]. Phone: 703-913-3800. Fax: 703-913-3897. † Geo-Centers, Inc.. ‡ Science Department. § Material Chemistry Branch. | Chemistry Department. ⊥ Navy Technology Center for Safety and Survivability. (1) MIL Spec, Military Specifications, Fuel, Naval Distillate. MILF-16884J, 1995. (2) ASTM Standard Specification for Diesel Fuel Oils Annual Book of ASTM Standards; ASTM: Philadelphia, 1999; Part 0.05.01, ASTM D 975-98a. (3) Lacey, P. I.; Erwin, J. Effect of Refining Severity on the Lubricity of NATO F-76 Fuel. Letter Report TFLRF No. 99-009, Contract No. DAAK 70-92-C0059; U.S. Army TARDEC Fuels and Lubricants Research Facility (TFLRF), Southwest Research Institute (SwRI): San Antonio, TX, July 2000.
unique set of six fuels was hydrotreated to four different sulfur and aromatic levels, the properties of which can be found in Table 2. Sulfur content was determined by ASTM D5453,4UV fluorescence, while hydrocarbon types were determined by ASTM D1319,5 fluorescent indicator adsorption. Specific gravity and density were measured following ASTM D 4052.6 The original feedstocks and hydrotreated samples were then measured for lubricity by three currently accepted ASTM methods, D50017 (BOCLE), D60788 (SLBOCLE), and D60799 (HFRR), Table 3. Using the pass criteria found at the bottom of Table 3, one observes that all the feedstocks had acceptable lubricity, by all three test methods. All the hydrotreated samples, except hydrotreat no. 1 from USA Gulf Coast, had unacceptable lubricity as measured by (4) ASTM Standard Test Method for Determination of Total Sulfur in Light Hydrocarbons, Motor Fuels and Oils by Ultraviolet Fluorescence. In Annual Book of ASTM Standards; ASTM: Philadelphia, 1999; Part 0.05.03, ASTM D5453-00. (5) ASTM Standard Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption. In Annual Book of ASTM Standards; ASTM: Philadelphia, 1999; Part 0.05.01, ASTM D1319-98. (6) ASTM Standard Test Method for Density and Relative Density of Liquids by Digital Density Meter. In Annual Book of ASTM Standards; ASTM: Philadelphia, 1999; Part 0.05.02, ASTM D405296. (7) ASTM Standard Test Method for Measurement of Lubricity of Aviation Turbine Fuels by the Ball-on-Cylinder Evaluator (BOCLE) In Annual Book of ASTM Standards; ASTM: Philadelphia, 1999; Part 0.05.03, ASTM D 5001-90a. (8) ASTM Standard Test Method for Evaluating Lubricity of Diesel Fuels by the Scuffing Load Ball-on-Cylinder Lubricity Evaluator (SLBOCLE). In Annual Book of ASTM Standards; ASTM: Philadelphia, 2000; Part 0.05.04, ASTM D 6078-99. (9) ASTM Standard Test Method for Evaluating Lubricity of Diesel Fuels by the High-Frequency Reciprocating Rig (HFRR), Annual Book of ASTM Standards; ASTM: Philadelphia, 2000, Part 0.05.04, ASTM D6079-99.
10.1021/ef010281b CCC: $25.00 © 2003 American Chemical Society Published on Web 02/13/2003
Hydrotreating Diesel Fuel
Energy & Fuels, Vol. 17, No. 2, 2003 445
Table 1. General Properties Required by Specifications for Various Diesel Fuels property
militarya
no. 1-Db
no. 2-Dc
no. 1d
no. 2e
mm2/s
1.7-4.3 1.0 60 -1 -6 12.5 43 0.20
1.3-2.4 0.05 38
1.9-4.1 0.05 52
1.3-2.4
1.9-4.1
40 0.15
40 0.35
0.15
0.35
viscosity at 40°C, sulfur, % mass, max. flash point, °C cloud point, °C, max pour point, °C hydrogen, % mass, min cetane number, min carbon residue, 10% bottoms, % mass, max a
b
c
Reference 1, also NATO F-76. High speed, high load engines. Low sulfur fuel. Low speed, high load engines. Low sulfur fuel. Special purpose burners. U. S. regulations required under 40 CFR Part 80 to contain Solvent Red 26 as dye. e General purpose heating fuel oil. U. S. regulations required under 40 CFR Part 80 to contain Solvent Red 26 as dye.
d
Table 2. Properties of Test Fuels sample
densitya (g/ml)
specific gravitya
sulfurb (ppm)
aromaticsc (vol %)
olefinsc (vol %)
saturatesc (vol %)
reference no. 2 diesel feedstock hydrotreat 1 hydrotreat 2 hydrotreat 3 hydrotreat 4 Israel feedstock hydrotreat 1 hydrotreat 2 hydrotreat 3 hydrotreat 4 Great Britain feedstock hydrotreat 1 hydrotreat 2 hydrotreat 3 hydrotreat 4 USA West Coast feedstock hydrotreat 1 hydrotreat 2 hydrotreat 3 hydrotreat 4 Spain feedstock hydrotreat 1 hydrotreat 2 hydrotreat 3 hydrotreat 4 USA Gulf Coast feedstock hydrotreat 1 hydrotreat 2 hydrotreat 3 hydrotreat 4
0.8512 0.8451 0.8389 0.8326 0.8280 0.8412 0.8347 0.8342 0.8268 0.8237 0.8657 0.8590 0.8560 0.8429 0.8276 0.8700 0.8601 0.8576 0.8467 0.8417 0.8444 0.8334 0.8329 0.8262 0.8219 0.8462 0.8427 0.8354 0.8305 0.8263
0.8517 0.8456 0.8394 0.8330 0.8285 0.8417 0.8351 0.8346 0.8272 0.8241 0.8662 0.8595 0.8564 0.8434 0.8280 0.8704 0.8606 0.8581 0.8471 0.8422 0.8745 0.8338 0.8333 0.8266 0.8223 0.8466 0.8432 0.8358 0.8309 0.8267
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