| Highly paraffinic, moderately aromatic distillate fuel blend stocks prepared by low pressure hydroprocessing of fischer-tropsch products -> Monitor Keywords |
|
|
 
Highly paraffinic, moderately aromatic distillate fuel blend stocks prepared by low pressure hydroprocessing of fischer-tropsch productsRelated Patent Categories: Mineral Oils: Processes And Products, Products And Compositions, FuelsHighly paraffinic, moderately aromatic distillate fuel blend stocks prepared by low pressure hydroprocessing of fischer-tropsch products description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070187291, Highly paraffinic, moderately aromatic distillate fuel blend stocks prepared by low pressure hydroprocessing of fischer-tropsch products. Brief Patent Description - Full Patent Description - Patent Application Claims
RELATED APPLICATIONS [0001] The present application is a continuation-in-part of U.S. application Ser. No. 09/999,667, "Distillate Fuel Blends from Fischer Tropsch Products with Improved Seal Swell Properties," filed Oct. 19, 2001, the contents of which are hereby incorporated by reference. The present application is also related to U.S. Patent Application No. ______ (Docket No. 005950-830) entitled "Stable, Moderately Unsaturated Distillate Fuel Blend Stock Prepared by Low Pressure Hydroprocessing of Fischer Tropsch Products," filed herewith. FIELD OF THE INVENTION [0002] The invention is directed to distillate fuels comprising a Fischer Tropsch distillate fuel blend stock, which have improved seal swell properties. BACKGROUND OF THE INVENTION [0003] Distillate fuel derived from the Fischer-Tropsch process is highly paraffinic and has excellent burning properties and very low sulfur. This makes Fischer-Tropsch products ideally suited for fuel use where environmental concerns are important. However, due to their highly paraffinic nature, Fischer-Tropsch distillate fuels have problems with poor seal swell properties. [0004] The impact of lowering the aromatic content of distillate fuels used as diesel fuel or jet fuel on seal swell in diesel and jet engines is known, and became important when California switched from conventional diesel fuel to Low Aromatics Diesel Fuel (LAD). LAD does not contain zero aromatics, but must contain less than 10%. Literature references related to the problems encountered with lowering the aromatic content of distillate fuels include: Transport Topics, National Newspaper of the Trucking Industry, Alexandria, Va., "Fuel Pump Leaks Tied to Low Sulfur," Oct. 11, 1993; Oil Express, "EPA's diesel rules leading to shortages, fleet problems, price hikes," Oct. 11, 1993, p 4; Marin Independent Journal, "Motorists in Marin angry over fuel change," Nov. 11, 1993, p A1; San Jose Mercury News, "Mechanics finger new diesel fuel," Dec. 3, 1993; and San Francisco Chronicle, "Problems With New Diesel Fuel, Clean Air, Angry California Drivers," Dec. 23, 1993. [0005] The problem of poor seal swell may be monitored by measuring the swelling of gaskets. The swelling of gaskets can be monitored by the use of known tests. For example, a description of test methodology is presented in SAE Paper No. 942018, "Effect of Automotive Gas Oil Composition on Elastomer Behavior," October 1994, which describes seal swell and hardness changes which were measured in test procedures, based as closely as possible, on a British Standard (BS) method BS 903 Part A 16 [British Standard Institute, `Methods for testing vulcanized rubber,` Part A 16:1987--Determination of the effect of liquids], which is broadly similar to American Society for Testing and Materials (ASTM) procedures D471 [Test Method for Rubber Property--Effect of Liquids] and D2240 [Test Method for Rubber Property--Durometer Hardness]." (See FIG. 12). The paper examines volume swelling of five types of elastomers: hydrogenated nitrile, low nitrile, medium nitrile and low nitrile rubbers, and fluorocarbon elastomer. [0006] A summary of work carried out to assess problems associated with California low sulfur/low aromatics fuels is presented in the California Governor's "Diesel Fuel Task Force Final Report," dated Mar. 29, 1996. The report notes results of measurements carried out on O-rings before and after immersion in fuels: volume and weight change by ASTM D471 [Test Method for Rubber Property--Effect of Liquids], hardness by ASTM D1415 [Test Method for Rubber Property--International Hardness], and modulus of elasticity, ultimate tensile strength and elongation by ASTM D1414 [Test Methods for Rubber O-Rings]. [0007] Since the transition from conventional distillate fuels to low aromatic fuels created problems with seal swell, greater seal swell problems associated with the transition to a highly paraffinic distillate fuel component made from a Fischer-Tropsch process are expected. The greater seal swell problems associated with Fischer-Tropsch distillate fuel components may limit the use of Fischer-Tropsch distillate fuel. [0008] One additional problem associated with highly paraffinic distillate fuels is that hydroprocessing of these fuels consumes hydrogen. Hydrogen can be expensive to produce and store if necessary. Therefore, it would be desirable to reduce or eliminate the need for this hydrogen. [0009] Accordingly, there is a need in the art for distillate fuels and distillate fuel blend stocks with acceptable seal swell properties. Finally, there is a need in the art for distillate fuels and distillate fuel blend stocks with satisfactory properties, which can be obtained from Fischer-Tropsch process products. This invention provides such distillate fuels and blend stocks and the processes for their manufacture. SUMMARY OF THE INVENTION [0010] The present invention relates to a distillate fuel comprising a Fischer Tropsch distillate fuel blend stock. The Fischer Tropsch distillate fuel blend stock comprises aromatics in an amount between 2 and 20 weight % and paraffins in an amount 80 weight % or greater. The Fischer Tropsch distillate fuel blend stock has a cetane index of greater than 60 and exhibits a volume change as measured by ASTM D471 of at least 0.25% using a Buta N nitrite O-Ring at 23+/-2.degree. C. for 70 hours. [0011] In another embodiment, the present invention relates to a Fischer-Tropsch diesel fuel blend stock. The Fischer-Tropsch diesel fuel blend stock comprises aromatics in an amount between 5 and 10 weight %, paraffins in an amount 90 weight % or greater, and sulfur in an amount less than 1 ppm. The aromatics comprise less than 20 weight % polynuclear aromatics and preferably less than 10 weight % polynuclear aromatics. Characteristics of the Fischer Tropsch diesel fuel blend stock include a cetane index greater than 60, a percent reflectance according to ASTM D6468 at 150.degree. C. in excess of 65% when measured at 90 minutes, and a volume change as measured by ASTM D471 of at least 0.5% using a Buta N nitrite O-Ring at 23+/-2.degree. C. for 70 hours. [0012] In yet another embodiment, the present invention relates to a Fischer Tropsch jet fuel blend stock. The Fischer Tropsch jet fuel blend stock comprises aromatics in an amount between 5 and 10 weight %, paraffins in an amount 90 weight % or greater, and sulfur in an amount less than 1 ppm. The aromatics comprise less than 20 weight % polynuclear aromatics and preferably less than 10 weight % polynuclear aromatics. Characteristics of the Fischer Tropsch jet fuel blend stock include a smoke point of 30 mm or greater, a passing rating in ASTM D324 1 (JFTOT Procedure) at 260.degree. C. for 2.5 hours, and a volume change as measured by ASTM D471 of at least 0.5% using a Buta N nitrile O-Ring at 23+/-2.degree. C. for 70 hours. [0013] In a further embodiment, the present invention relates to a process for preparing a highly paraffinic, moderately aromatic distillate fuel blend stock. The process comprises converting syngas to a Fischer Tropsch derived feedstock by a Fischer Tropsch process, and hydroprocessing the Fischer-Tropsch derived feedstock. A highly paraffinic, moderately aromatic distillate fuel blend stock that contains between 2 and 20 weight % aromatics and 80 weight % or greater paraffins is recovered. Hydroprocessing conditions include a temperature of 525-775.degree. F., a pressure of less than 1000 psig, and a liquid hourly space velocity of greater than 0.25 hr.sup.-1. [0014] In yet a further embodiment, the present invention relates to a process for preparing a highly paraffinic, moderately aromatic distillate fuel blend stock comprising converting syngas to a Fischer Tropsch derived feedstock by a Fischer Tropsch process, and hydroprocessing the Fischer-Tropsch derived feedstock to produce a distillate fuel blend stock. To the distillate fuel blend stock is added an aromatic blend stock to produce a highly paraffinic, moderately aromatic distillate fuel blend stock containing between 2 and 20 weight % aromatics and 80 weight % or greater paraffins. [0015] In another embodiment, the present invention relates to a distillate fuel comprising a Fischer Tropsch distillate fuel blend stock. The Fischer Tropsch distillate fuel blend stock is made by a process comprising converting syngas to a Fischer Tropsch derived feedstock by a Fischer Tropsch process; hydroprocessing the Fischer-Tropsch derived feedstock at a temperature of 525-775.degree. F., a pressure of less than 1000 psig, and a liquid hourly space velocity of greater than 0.25 hr.sup.-1; and recovering a Fischer Tropsch distillate fuel blend stock. The Fischer Tropsch distillate fuel blend stock, which is recovered, comprises between 2 and 20 weight % aromatics and 80 weight % or greater paraffins. [0016] In a further embodiment, the present invention relates to a method of operating a diesel engine comprising using a Fischer Tropsch diesel fuel blend stock as a diesel fuel wherein the Fischer Tropsch diesel fuel blend stock comprises aromatics in an amount between 5 and 10 weight %, paraffins in an amount 90 weight % or greater, and sulfur in an amount less than 1 ppm. The aromatics comprise less than 20 weight % polynuclear aromatics and preferably less than 10 weight % polynuclear aromatics. Characteristics of the Fischer Tropsch diesel fuel blend stock include a cetane index greater than 60, a percent reflectance according to ASTM D6468 at 150.degree. C. in excess of 65% when measured at 90 minutes, and a volume change as measured by ASTM D471 of at least 0.5% using a Buta N nitrile O-Ring at 23+/-2.degree. C. for 70 hours. [0017] In yet another embodiment, the present invention relates to a method of operating a jet engine comprising using a Fischer Tropsch jet fuel blend stock as a jet fuel wherein the Fischer Tropsch jet fuel blend stock comprises aromatics in an amount between 5 and 10 weight %, paraffins in an amount 90 weight % or greater, and sulfur in an amount less than 1 ppm. The aromatics comprise less than 20 weight % polynuclear aromatics and preferably less than 10 weight % polynuclear aromatics. Characteristics of the Fischer Tropsch jet fuel blend stock include a smoke point of 30 mm or greater, a passing rating in ASTM D3241 (JFTOT Procedure) at 260.degree. C. for 2.5 hours, and a volume change as measured by ASTM D471 of at least 0.5% using a Buta N nitrile O-Ring at 23+/-2.degree. C. for 70 hours. BRIEF DESCRIPTION OF THE DRAWINGS [0018] FIG. 1 is a schematic flow diagram of one embodiment of the invention. [0019] FIG. 2 is a graphical representation of the relationship between volume change and cetane index of blends of highly paraffinic distillate fuel blend stock and alkylaromatics or alkylcycloparaffins as described in the examples. Continue reading about Highly paraffinic, moderately aromatic distillate fuel blend stocks prepared by low pressure hydroprocessing of fischer-tropsch products... Full patent description for Highly paraffinic, moderately aromatic distillate fuel blend stocks prepared by low pressure hydroprocessing of fischer-tropsch products Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Highly paraffinic, moderately aromatic distillate fuel blend stocks prepared by low pressure hydroprocessing of fischer-tropsch products patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Highly paraffinic, moderately aromatic distillate fuel blend stocks prepared by low pressure hydroprocessing of fischer-tropsch products or other areas of interest. ### Previous Patent Application: A diesel fuel and a method of operating a diesel engine Next Patent Application: Stable, moderately unsaturated distillate fuel blend stocks prepared by low pressure hydroprocessing of fischer-tropsch products Industry Class: Mineral oils: processes and products ### FreshPatents.com Support Thank you for viewing the Highly paraffinic, moderately aromatic distillate fuel blend stocks prepared by low pressure hydroprocessing of fischer-tropsch products patent info. IP-related news and info Results in 0.1654 seconds Other interesting Feshpatents.com categories: Computers: Graphics , I/O , Processors , Dyn. Storage , Static Storage , Printers 174 |
 * Protect your Inventions * US Patent Office filing 
PATENT INFO |
|
