JP2003517090A - Fuel composition - Google Patents

Abstract

(57) Abstract: The present invention relates to a diesel fuel composition having improved lubricity, wherein the composition has a sulfur content of less than 25 ppm and an aromatic content of about 12% or more, and the fuel composition has a sulfur content of 40% or less. It is characterized in that the measured kinematic viscosity (KV ₄₀ ) is greater than 3.0 cSt. Such compositions do not require the use of conventional lubricity improvers or exhibit the desired lubricity with very small amounts used.

Description

Detailed Description of the Invention

The present invention relates to a fuel composition having a low sulfur content and a high viscosity, which has improved lubricity and thus less dependence on a lubricity enhancing additive. Fuels such as diesel fuel are widely used for motor vehicle transportation due to their low cost. However, the relatively high concentration of sulfur compounds is one of the problems with this type of fuel. Excessive sulfur is a particulate exhaust material and reduces the effectiveness of the exhaust gas aftertreatment technology that is being introduced in response to exhaust gas regulations. Therefore, the allowable levels of sulfur in diesel fuel have been gradually reduced over the years, and further reductions are planned in the future.
Sulfur content can be easily reduced by using known methods such as hydrodesulfurization, which is usually performed in the presence of a catalyst, but such treatment can also adversely affect the lubricity of the desulfurized product. . This hydrotreatment also reduces the content of aromatic compounds in the fuel composition. Reducing the content of aromatic compounds is also thought to be effective for exhaust gas, and although the California Air Resources Board limited aromatics to 10%,
Higher aromatics content of the fuel will prove to be comparable to emissions, and will allow for such a dispensation. Nikan
jam, Henderson (SAE 920825) showed that a reduction in aromatic content adversely affected lubricity. The researchers have shown that low aromatic content fuels can be remedied by back-blending with conventional aromatic content commercial blends.

Therefore, in order to minimize wear and friction when used in automobile engines and to minimize damage to the injection system in diesel engines, the sulfur content is low but the desired lubricity is obtained. The composition must be prescribed. Heretofore, anti-wear agents including fatty acids, fatty acid esters, lactones, polyoxyalkylene ethers, amino compounds and the like have been added to formulations for the above purposes. However, compositions containing compounds such as esters are expensive in terms of both their material costs and the cost of additive storage equipment. In the presentation of “The lubricity of diesel fuels” by Wei and Spikes on “Wear” 111 (1986) p. 217, heterocyclic nitrogen compounds such as quinoline and indole also have excellent effects on the wear resistance of base fuels. There is a disclosure. These compounds have been studied because they fall into the category of compounds having the same general structure as natural compounds which are decomposed during hydrotreating. Further, “Lubrication Science” 1989, 2 (1), pages 63 to 67, D.M. “The Influence of Chemical Structure of Certain Nitro” by Wei et al.
gen-Containing Organic Compounds on Their Antiwear Effectiveness: The Cr
A paper entitled "Itical Role of Hydroxy Group" discloses the discovery that certain nitrogen-containing compounds have significantly improved their wear resistance due to the hydroxyl groups contained therein, and that hydroxy-substituted benzothiazole compounds reduce wear. It is described that it is most effective in terms of abrasion resistance. To this end, the authors have tested the film formed on the rubbed surface with and without benzo derivatives of pyridine and thiazole, with or without hydroxyl groups on the ring, and describe the results. ing. This paper concludes that the protective film formed by the above heterocyclic compound containing a hydroxyl group on the rubbed surface is very different from the protective film formed by a similar compound having similar chemical composition and physical properties. Is issued. JP-A-110001692 uses a specific mixture of fatty acid esters having 8 to 30 carbon atoms and has a low sulfur content of 40% by weight or less of aromatic content suitable for diesel fuel (
(Less than 0.2% by weight) The lubricity of middle distillate fuel oil is improved. Nothing is said about the viscosity of this final fuel oil.

In any of these cases, the lubricity-improving component usually has to be separately synthesized and introduced into the fuel through an external additive. This not only wastes resources, but also spreads chemicals in this area. In addition, extensive testing is required to confirm that these externally supplied additives do not have unwanted side effects. RU-A-2079542, which has already been published, relates to a high-viscosity fuel for a marine diesel engine, which fuel is a narrow fraction (boiling range 350-500 ° C) obtained by atmospheric distillation of petroleum, and suppresses it. It contains a depressor additive in the form of a residue (density 1040 to 1095 kg / m ³ ) due to thermal decomposition. No mention is made here of the sulfur content or the viscosity of the final product. It has been found that increasing the viscosity of the fuel has an excellent effect on the lubricity of the fuel composition of ultra-low sulfur content. Fuels formulated to high viscosities have improved lubricity without excessive reliance on additives from external sources.

Accordingly, the present invention is a diesel fuel composition having improved lubricity, having a sulfur content of less than 25 ppm and an aromatic content of about 12% or more, and having a kinematic viscosity of the fuel composition measured at 40 ° C. Provided is a diesel fuel composition characterized by a KV ₄₀ ) of greater than 3.0 cSt. Such fuel compositions are prepared by blending at least two components, one having a relatively higher viscosity than the final fuel composition and the other a lower viscosity than the final fuel composition. . When blended in this way, the relative volume ratio of the relatively high viscosity component to the relatively low viscosity component can be very wide depending on the respective viscosities and the amounts blended, for example 10:90. To 80:
Twenty. A suitable volume ratio is 70:30 to 80:20. Conventional hydrotreated fuels can be used as the relatively high viscosity component, but this is the secondary treatment of refined product streams such as pipestills (eg heavy gas oil) or hydrocracking of refinery processes ( That is, it can be obtained from any of the hydrocracked oils). Strict hydrotreatment of such components may reduce the sulfur content, but the aromatic content still remains. This aromatic content is usually 12 to
Will be 35%. In one embodiment, the fuel composition of the present invention comprises a relatively viscous refinery stream from a hydrocracker (which may itself be a blend) and an automotive diesel oil (ADO) of normal viscosity. Alternatively, it can be prepared by blending with a low viscosity component such as kerosene. A fuel composition having a viscosity KV ₄₀ of greater than 3.0 cSt can be formulated by blending these components in appropriate proportions. For example, a component KV ₄₀ is hydrocracked in 6.7CSt, can KV ₄₀ is blended at a volume ratio of 74:26 and a low viscosity component of 1.1CSt, resulting, KV ₄₀ 3. A 6 cSt blend is obtained. Alternatively, ultra low sulfur automobile diesel oil with a sulfur content of 10 ppm and a KV ₄₀ of 2.6 cSt (
If "ULSADO") and the above hydrocracked components were blended in a ratio of 80:20, the resulting blend would have a viscosity of 3.0 cSt.

The fuel composition of the present invention provides lubricity that is durable to use when used in a diesel fuel injection device that is not easily affected by wear. Rotary distribution devices such as pumps are much more susceptible to wear and the fuel itself is the lubricant, but even in such devices the fuel composition of the invention has improved lubricity. Thus, the concentration of conventional additives required to bring lubricity to acceptable levels can be reduced. These pumps consist of precisely designed parts,
It is intended to maintain the fuel injection volume consistently and accurately to ensure a long useful life. Worn parts of the pump can lead to irregular fuel injection, poor driveability, increased emissions and eventually the pump not working. The diesel fuel composition has a sulfur content of less than 25 ppm, suitably less than 10 ppm, and a fuel of zero sulfur content is preferred. There are various ways to achieve this low sulfur content. For example, a known method such as a hydrogenation-type catalytic desulfurization method may be used. In addition, the KV _{40 of the} fuel composition is greater than 3.0 cSt and 3.5 cS
A KV ₄₀ greater than t is preferred.

The base fuel of the present invention may contain a mixture of saturated hydrocarbon compounds, olefins, aromatic hydrocarbon compounds. These hydrocarbon compounds may be straight run streams, pyrolyzed or catalytically cracked hydrocarbon feedstocks, hydrocracked petroleum fractions,
It can be derived from catalytically reformed hydrocarbons or synthetically produced hydrocarbon mixtures. The invention is particularly suitable for fuels having a sulfur content of less than 25 ppm, in which the naturally lubricating polar compounds are reduced to ineffective levels during processing. The fuel composition of the present invention will contain more than normal high viscosity components from pipestill or from secondary treatments such as hydrocracking. Methods of processing crude oil to obtain various process streams are well known in the art, for example, “Auto
motive Fuels Reference Book ”Keith Owen, Trevor Colley, 2nd edition, the Societ
Details are described in y of Automotive Engineers, Inc, Warrendale, PA, USA (1995). To be specific, Chapter 3 pages 29 to 49, Chapter 15 3 of this book
See Diesel Fuel Characteristic Influencing Combustion on pages 85-418.
”, Chapter 5 on Lubricating Additives for Diesel Fuels, pages 519-522, and Appendix 12“ Glossary ”on pages 865-890, which provides the information needed to create and characterize streams. Will provide everything.

The wear resistance and lubricity of the fuel composition of the present invention are measured by a so-called light oil lubricity test (hereinafter referred to as “
"HFRR"). This HFRR test shows a loaded diameter of 6
A mm ball is used to make a reciprocating motion with respect to the resting plate underneath. Through this test both frictional resistance and contact resistance are examined. This test is C
According to standard procedures published as EC F-06-A-96,
A load of 2 N (200 g) was applied, the stroke length was 1 mm, the reciprocating frequency was 50 Hz, and the sample temperature was 60 ° C. The ambient temperature and humidity were adjusted within the specified range, the diameter of the wear scar was calculated, and the calculated value was corrected to a value corresponding to the standardized water vapor pressure of 1.4 kPa. The ball of the test piece is grade 28 (ANSI B3.12), AISI E-
The hardness number (HRC) of Rockwell C of 52100 is 58 to 66 (ISO6508).
), The steel ball has a surface roughness _Ra (centerline average roughness) of less than 0.05 μm. The lower plate is AISI cut from an annealed rod
E-52000 steel plate, Vickers hardness HV30 scale 190-210
(ISO6507 / 1). After turning, this steel sheet is lapped and polished with a surface finish _Ra of 0.02 μm.

[0008]

[Table 1] Overview of HFRR test conditions A series of test samples were prepared by blending refined components from the hydrocracker with low viscosity kerosene with a sulfur content of 11 ppm. Details of these blending components are shown in Table 2 below. Table 3 details the blending ratio KV ₄₀ (ASTM D445-9
7 / 446-97) and the aromatic composition according to IP391-95.

[0009]

[Table 2] Composition of components for blending RA-aromatic ring

[0010]

[Table 3] Details of basic fuel blend products RA-Aromatic Rings According to this data, the blends prepared have a KV _{40 range} of 2.0 to 4.0.
Although there is cSt, it can be seen that the content of aromatics is the same as that of ordinary diesel fuel. Blends 1 to 3 (Invention) are compared to Blends 4 and 5 with KV ₄₀ less than 3.0 cSt (Comparative Tests not according to the invention). Table 4 below shows the results of HFRR testing of the base fuel blend without any additives and the low and high viscosity blends with ester lubricants.

[0011]

[Table 4] Lubricating performance by HFRR of test blend

From the results in the column of the basic fuel blended product, it is understood that, as the viscosity of the blended products 1 to 5 decreases, the lubricity also has an adverse result corresponding thereto. The HFRR test results for blends 1 and 5 with ester lubricants show that the effect of this addition varies along the addition concentration curve, which results in the claimed performance specification (460 μm) at low additive concentrations. It provides the means to meet.

─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Barlowitz Paul Jay             New Jersey, United States             08826 Glenn Gunder Nicole             Terrace 4 (72) Inventor Rickard David John             British Sally Katie 22 8 E             Qusui Leatherhead Armin We             Yes ess house mail point 12               Patents and Licensees (72) Inventor Shirowitz Alan Mark             British Sally Katie 22 8 E             Qusui Leatherhead Armin We             Yes ess house mail point 12               Patents and Licensees

Claims (8)

[Claims] 1. A diesel fuel composition having an improved lubricity having a sulfur content of less than 25 ppm and an aromatic content of about 12% or more, the kinematic viscosity (KV ₄₀ ) of the fuel composition measured at 40 ° C. Diesel fuel composition characterized by being greater than 3.0 cSt. 2. The composition of claim 1, wherein the composition has a KV ₄₀ of greater than 3.5 cSt. 3. The fuel composition is prepared by blending a component having a relatively higher viscosity than the final fuel composition with a component having a relatively lower viscosity than the final fuel composition. The composition according to 1 or 2. 4. The weight ratio of the relatively high viscosity component to the relatively low viscosity component is
The composition according to any one of claims 1 to 3, which is in the range of 10:90 to 80:20. 5. The weight ratio of the relatively high viscosity component to the relatively low viscosity component is
A composition according to claim 3 or 4 in the range of 70:30 to 80:20. 6. The relatively high viscosity component is a hydrocracked oil that may be a blend itself, obtained from a refinery process stream, and the relatively low viscosity component is selected from ADO or kerosene. The composition according to any one of claims 2 to 5. 7. The aromatic content of the composition is about 12-35%.
The composition according to any one of 6 above. 8. The composition according to claim 1, wherein the sulfur content in the composition is less than 10 ppm.