Mineral oils: processes and products – Products and compositions – Fuels
Reexamination Certificate
1999-11-10
2001-10-09
McAvoy, Ellen M. (Department: 1764)
Mineral oils: processes and products
Products and compositions
Fuels
C208S057000, C208S143000, C208S144000
Reexamination Certificate
active
06299758
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to low sulfur gas oils derived from petroleum distillation fractions, and more particularly to low sulfur gas oils suitable for use as a diesel oil.
2. Description of the Prior Art
Currently, diesel gas oils have been produced by mixing a desulfurized gas oil base obtained by treating a straight gas oil using a conventional desulfurization reaction apparatus, with base materials or gas oil fractions. Such base materials are those produced by hydrocracking a heavy oil. Such gas oil fractions are those produced by thermal cracking or catalytic cracking a heavy oil. On the circumstances, the base material are those obtained by hydro-refining such gas oil fractions. In this connection, there are two choices to reduce the sulfur concentration of a final gas oil. One is to reduce the sulfur concentration of each base materials. The other is to produce a base material of an extremely low sulfur concentration and then to mix it with another base material to an extent of allowable sulfur concentration.
However, recent issues concerning with the environment have required reducing the amounts of NOx and particulates contained in the exhaust gas of diesel engine automobiles. In many foreign countries, there are some movements regarding a regulation emphasizing to decrease the sulfur concentration of diesel gas oils. Specifically, the regulation requires gradually bringing down the sulfur concentration of a diesel oil from 500 ppm which is currently accepted, to 350 ppm and to 50 ppm in the feature. However, conventional methods are limited to produce a diesel gas oil having a sulfur concentration of 500 ppm.
An object of the present invention is to provide a low sulfur diesel gas oil of less than 350 ppm or below, furthermore 50 ppm or below in sulfur concentration causing the formation of particulates in the exhaust gas of a diesel engine automobile.
It has now been found after an extensive research and study that the expected low sulfur gas oil can be produced by using one or more gas oil bases obtained by hydrogenating some specific fractions of petroleum distillations under the certain conditions or alternatively by mixing one or more of these gas oil bases with a small amount of straight kerosene or gas oil.
According to one aspect of the present invention, there is provided with a low sulfur gas oil at least 90% of total volume which consists of one or more gas oil bases (a) to (d) below and the sulfur concentration of which is no greater than 350 ppm:
(a) a gas oil base produced by hydrodesulfurizating a fraction obtained from an atmospheric pressure distillation column and having a 5% recovered temperature in the range of 140 to 310° C. and a 90% recovered temperature of lower than 340° C., under reaction conditions with a hydrogen partial pressure of 20 to 70 kg/cm
2
, an LHSV (liquid hourly space velocity) of 1.0 to 20.0 and a reaction temperature of 280 to 450° C.;
(b) a gas oil base produced by hydrodesulfurizating a fraction obtained from an atmospheric pressure distillation column and having a 5% recovered temperature in the range of 140 to 340° C. and a 90% recovered temperature of lower than 340 to 380° C., under reaction conditions with a hydrogen partial pressure of 20 to 150 kg/cm
2
, an LHSV of 0.1 to 10.0 and a reaction temperature of 330 to 450° C.;
(c) a gas oil base having an initial boiling point of 260° C. or higher and a 90% recovered temperature of 345° C. or below and obtained from fractions produced by hydrocracking a fraction obtained from an atmospheric distillation column and having an initial boiling point of 260° C. or higher and/or a vacuum gas oil obtained from a vacuum distillation column, under reaction conditions with a hydrogen partial pressure of 30 to 100 kg/cm
2
, an LHSV of 0.1 to 10.0 and a reaction temperature of 330 to 450° C.; and
(d) a gas oil base having an initial boiling point of 260° C. or higher and a 90% recovered temperature of 365° C. or below and obtained from fractions produced by hydrocracking a fraction obtained from an atmospheric distillation column and having an initial boiling point of 260° C. or higher in and/or a vacuum gas oil obtained from a vacuum distillation column, under reaction conditions with a hydrogen partial pressure of 100 to 250 kg/cm
2
, an LHSV of 0.1 to 10.0 and a reaction temperature of 350 to 450° C.
According to the other aspect of the present invention, there is provided a low sulfur gas oil the total volume of which consists of one or more of the above-described gas oil basses (a) to (d) and the sulfur content of which is no greater than 50 ppm.
DETAILED DESCRIPTION OF THE INVENTION
Preparation of Gas Oil Base (a)
The starting material used is a petroleum fraction (A) having a 5% recovered temperature of 140 to 310° C. and a 90% recovered temperature of lower than 340° C. The sulfur concentration of this petroleum fraction is preferably in the range of 0.5 to 2.0 weight percent. The petroleum fraction (A) is subjected to hydrodesulfurization under reaction conditions with a hydrogen partial pressure of 20 to 70 kg/cm
2
, an LHSV of 0.1 to 20.0 and a reaction temperature of 280 to 450° C.
The hydrogen partial pressure may be selected from the range from 20 to 70 kg/cm
2
, but is preferably selected within the range from 25 to 65 kg/cm
2
, and more preferably 30 to 60 kg/cm
2
.
The LHSV may be selected within the range of 0.1 to 20.0, but is preferably selected within the range of 1.0 to 15.0, and more preferably 2.0 to 10.0.
The reaction temperature may be selected within the range of 280 to 450° C., but is preferably selected within the range of 290 to 410° C., and more preferably 300 to 380° C.
The catalyst used may be those commonly employed to hydrorefining a petroleum distillation fraction. Specific examples of such catalysts are those composed of active metals supported on porous inorganic oxides such as alumina, silica, titania, boria, zirconia, silica-alumina, silica-magnesia, alumina-magnesia, alumina-titania, silica-titania, alumina-boria and alumina-zirconia. The active metals may be one or more types of metals selected from the group consisting of chromium, molybdenum, tungsten, cobalt and nickel. These active metals may be supported on the carrier in the form of metals, oxides, sulfides or mixtures thereof. The amount of active metal to be supported on the carrier is preferably in the range of 1 to 20 weight percent in the form of its oxide. The catalyst may be in the form of granules, tablets or columns.
In the present invention, it is preferred to use the catalyst having a combination of two or three different types of active metals, such as cobalt-molybdenum, nickel-molybdenum or cobalt-nickel-molybdenum, support on the alumina carrier.
The catalyst is preferably preliminary sulfurized by a known method prior to its use in the hydrogenation treatment.
The hydrogenation treatment reactor may be in the form of a fixed bed, fluidized bed or expansion bed, but a fixed bed is particularly preferred.
Contact between hydrogen, the petroleum fraction (A) and the catalyst may be conducted using a parallel upward current flow, parallel downward current flow or counter-current flow system.
Preparation of Gas Oil Base (b)
The starting material used is a petroleum fraction (B) having a 5% recovered temperature of 140 to 340° C. and a 90% recovered temperature of 340 to 380° C. The sulfur concentration of this petroleum fraction is preferably in the range of 0.5 to 2.0 weight percent. The petroleum fraction (B) is subjected to hydrodesulfurization under reaction conditions with a hydrogen partial pressure of 20 to 150 kg/cm
2
, an LHSV of 0.1 to 10.0 and a reaction temperature of 330 to 450° C.
The hydrogen partial pressure may be selected from the range of 20 to 150 kg/cm
2
, but is preferably selected within the range of 30 to 140 kg/cm
2
, and more preferably 40 to 120 kg/cm
2
.
The LHSV may be selected within the range of 0.1 to 10.0, but is preferably selected within the range of 0.7 to 7.0, and more preferably 0.5 to
Adachi Michiaki
Ishikawa Katsuhiko
Okazaki Hajime
Waku Toshio
Akin Gump Strauss Hauer & Feld L.L.P.
McAvoy Ellen M.
Nippon Mitsubishi Oil Corporation
LandOfFree
Low sulfur gas oil does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Low sulfur gas oil, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low sulfur gas oil will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2612368