Mineral oils: processes and products – Products and compositions – Fuels
Reexamination Certificate
1998-09-01
2002-10-08
Preisch, Nadine (Department: 1764)
Mineral oils: processes and products
Products and compositions
Fuels
C585S001000, C585S014000, C044S300000
Reexamination Certificate
active
06461497
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a reformulated diesel fuel meeting the requirements of ASTM D975-96a and providing significantly reduced emissions by comparison to a certified diesel fuel, certified under Section 2282, Title 13, California Code of Regulations.
2. Description of the Related Art
Federal and state legislative bodies and agencies have issued a number of rules applicable to the production of clean diesel fuel in attempts to reduce emissions from heavy-duty vehicles of NO
x
, carbon monoxide, unburned hydrocarbons, and particulate matter. Diesel fuel properties given the most attention are cetane number, aromatics content, and sulfur content. Federal regulations, for instance, require vehicular diesel fuel sold beginning Oct. 1, 1993 to have a maximum sulfur content of 0.05 percent and a minimum cetane index of 40 or a maximum aromatics content of 35 percent.
Some states have issued more demanding requirements. For example, the California Air Resources Board (“CARB”) has adopted Section 2282, Title 13, California Code of Regulations (“Section 2282”) which limits the aromatic hydrocarbon content of diesel fuel sold or intended for sale as a motor vehicle fuel in California starting Oct. 1, 1993.
Section 2282 establishes a basic California statewide aromatic hydrocarbon limit for vehicular diesel fuel of 10 percent by volume with a less stringent 20 percent standard for small refiners and a temporary 20 percent standard for independent refiners.
Sections 2282(a)(1)(C) and 2282(g) allow diesel fuel producers and importers to comply with the regulation with a set of diesel fuel specifications of their choosing if they can demonstrate that the alternative specifications result in emission benefits at least equivalent to the emission benefits resulting from a 10 volume percent aromatic hydrocarbon standard (or, in the case of small refiners, the 20 percent aromatic hydrocarbon standard) reference fuel.
Section 2282(g) identifies a test procedure for comparative testing of a candidate fuel and a reference fuel representative of a diesel fuel with 10 percent aromatic hydrocarbons (or 20 percent by volume for small refiners) as specified in Section 2282(g) involving back-to-back tests using a specified heavy-duty diesel engine and identifies the statistical methodology to be used in comparing the emissions of NO
x
, particulate matter, and the soluble organic fraction of the particulate matter resulting from the two fuels, and establishes a process for certifying diesel fuel formulations that satisfy the regulatory criteria.
The reference fuel is defined as shown in Table I.
TABLE 1
Reference Fuel Specifications
General
Small Refiner
ASTM
Reference Fuel
Reference Fuel
Property
Test Method*
Specifications
Specifications
Sulfur Content
D2622-82
500 ppm max.
500 ppm max.
Aromatic Hydrocarbon
D1319-84
10% max.
20% max.
Content, Vol. %
Polycyclic Aromatic
D2425-83
1.4% max.
4% max.
Hydrocarbon Content,
Wt. %
Nitrogen Content
D4629-86
10 ppm max.
90 ppm max.
Natural Cetane
D613-84
48 minimum
47 minimum
Number
Gravity, API
D287-82
33-39
33-39
Viscosity at 40°, cSt
D445-83
2.0-4.1
2.0-4.1
Flash point, ° F.,
D93-80
130
130
(min.)
Distillation, ° F.
D86-82
IBP
340-420
340-420
10% REC.
400-490
400-490
50% REC.
470-560
470-560
90% REC.
550-610
550-610
EP
580-660
580-660
*The listed ASTM methods are incorporated herein by reference.
Exhaust emission tests using the candidate fuel and the reference fuel shall be conducted in accordance with the “California Exhaust Emission Standards and Test Procedures for 1985 and Subsequent Model Heavy-Duty Diesel-Powered Engines and Vehicles,” as incorporated by reference in Title 13, California Code of Regulations, Section 1956.8(b). The tests shall be performed using a Detroit Diesel Corporation. Series-60 engine, or, if the executive officer determines that the Series-60 is no longer representative of the post-1990 model year heavy-duty diesel engine fleet, another engine found by the executive officer to be representative of such engines.
Section 2282(g)(1) requires that an applicant for certification submit to the Executive Officer of CARB for approval a proposed test protocol which includes detailed information on the entity proposed to conduct the tests, the test procedures, analytical test data on the candidate and reference fuels, the quality control and quality assurance procedures, and identification of any statistical outlier tests to be used. The same section also provides procedures for applicants to submit a certification application which includes the approved test protocol, all of the test data, a copy of the complete test log, and a demonstration that the candidate fuel meets the requirements for certification.
If the Executive Officer of CARB finds that the candidate fuel has been properly tested and meets the performance criteria, an Executive Order certifying the diesel fuel formulation will be issued which assigns an identification name to the specific certified diesel fuel. The Order must specify that the certified diesel fuel formulation has the following specifications: (1) a sulfur content, a total aromatic hydrocarbon content, a polycyclic aromatic hydrocarbon content, and a nitrogen content not exceeding that of the candidate fuel; (2) a cetane number not less than that of the candidate fuel; and (3) presence of all additives that were contained in the candidate fuel in a concentration not less than in the candidate fuel, except for an additive demonstrated by the applicant to have the sole effect of increasing cetane number.
Prior to Oct. 1, 1993, many refiners in California were marketing diesel fuels which contained 35% or more aromatics. The aromatics were considered to cause a problem in the diesel fuel emissions and CARB indicated that the lower aromatics content of 10% or less was an attempt to reduce diesel fuel particulates and NO
x
emissions. While CARB imposed a limit of 10 volume percent, it has developed that many refiners marketed and continue to market diesel fuels which contain in excess of 20 volume percent aromatics as a result of the alternative fuel certification process. In other words, diesel fuels having an aromatics content much higher than 10 volume percent have been prepared, tested as required by CARB against the 10% aromatics reference fuel, and certified with a much higher aromatics content.
S.I.R. H1553 “Clean Diesel Fuel and Methods of Producing Clean Diesel Fuel”, published Jul. 2, 1996 by Michael J. Pedersen, is hereby incorporated in its entirety by reference. This publication discloses a method for producing a clean diesel fuel and discloses in Example 3 the preparation of two test diesel fuels D-25 and D-26 which were prepared as described in the application, and which were subsequently certified by CARB. The certification numbers for these fuels are Executive Order G-714-007 and Executive Order G-714-008. The properties of these fuels are disclosed at column 15, at lines 6-22. The test results of the standardized combustion tests for certification are shown in Tables 3 and 4 in column 17. It will be noted that these fuels have aromatic contents of 21.7 volume percent and 24.7 volume percent, respectively.
U.S. Pat. No. 5,792,339 “Diesel Fuel”, issued Aug. 11, 1998 to Robert L. Russell and assigned on its face to Tosco Corporation, is hereby incorporated in its entirety by reference. This reference discloses, in Table 3 in column 4, the properties of two diesel fuels which are the subject of the claimed invention, two ARCO fuels shown as ARCO D-25 and D-26, three Chevron fuels shown as Chevron D-4781, F-2 and G-2, and one Texaco fuel. Upon observation of these fuels, it is noted that these fuels have aromatic contents varying from 15 weight percent up to 24.7 weight percent. These fuels also contain sulfur in amounts from less than 5 parts per million by weight (ppmw) up to 496 ppmw. The fuels also include polycyclic aromatics in an amount equal to from about 1.9 to about 8.6 weight percent. The nitrog
Atlantic Richfield Company
McDonald Scott P.
Preisch Nadine
Scott F. Lindsey
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