JP2003027070A - Method for desulfurizing cracked gasoline fraction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to perform the desulfurization of a cracked gasoline while controlling the hydrogenation of an olefin of a high octane value to thereby obtain a gasoline having a high octane value and a low sulfur content. SOLUTION: This method for desulfurizing a cracked gasoline fraction is characterized in that the desulfurization is performed by using a desulfurization catalyst prepared by accumulating coke on the surface of a catalyst which comprises an inorganic oxide carrying a desulfurization activating metal and has a mean pore diameter of 85 Å or larger, with the amount of the coke accumulated being 30-50 wt.% based on the weight of the catalyst.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for desulfurizing cracked gasoline, and more particularly to a method for desulfurizing cracked gasoline using a waste catalyst having accumulated coke.

[0002]

Generally, fluid catalytic cracking (FCC) equipment,
Catalytic cracking gasoline manufactured by a heavy oil fluid catalytic cracking (RFCC) unit or cracked gasoline manufactured by a thermal cracking unit such as a coker contains a sulfur compound which is an air pollutant. Therefore, it is urgent for oil refining companies to remove sulfur from these cracked gasolines to produce eco-friendly gasolines. In addition, cracked gasoline usually contains a large amount of olefin, which is a high-octane substance that increases the efficiency of gasoline automobile engines. Therefore, when removing sulfur from cracked gasoline,
It is necessary to maintain the octane number as high as possible by keeping the olefin content as small as possible. As the above-mentioned technique, a method of hydrodesulfurizing a cracked gasoline fraction containing an olefin component having a high octane number component (Japanese Patent Laid-Open No. 7-15774).
Issue gazette).

[0003]

However, the catalyst used here is a waste catalyst to which coke adheres in the vacuum gas oil desulfurization apparatus or the gas oil desulfurization apparatus. Since these catalysts are originally relatively light vacuum gas oils or catalysts for gas oil treatment, even a used waste catalyst has a very high hydrogenation activity. Therefore,
Even when a used spent catalyst with accumulated coke and reduced activity is used, there is a drawback that not only the desulfurization reaction of cracked gasoline occurs but also the hydrogenation reaction of olefins with a high octane number proceeds. It was The present invention has been made under such circumstances, and in particular, desulfurization of a cracked gasoline fraction is performed while suppressing hydrogenation of an olefin having a high octane number, and as a result, a gasoline having a high octane number and a low sulfur content is obtained. The purpose is to provide a possible method.

[0004]

As a result of intensive studies in view of the above problems, the present inventors have found that a desulfurization catalyst having a specific average pore diameter and accumulating a specific amount of coke. It has been found that the above-mentioned objects of the present invention can be achieved by using them. That is, the present invention provides a desulfurization catalyst obtained by accumulating 30 to 50% by weight of the catalyst weight of coke on the surface of a catalyst having an average pore diameter of 85 Å or more, which is obtained by supporting a desulfurization active metal on an inorganic oxide carrier. The present invention relates to a method for desulfurizing a cracked gasoline fraction, which comprises desulfurizing a cracked gasoline fraction using the same.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. The desulfurization catalyst used in the desulfurization method of the present invention has an average pore diameter of 85Å formed by supporting a desulfurization active metal on an inorganic oxide carrier.
On the surface of the above catalyst, 30 to 50% by weight of coke of the total desulfurization catalyst is accumulated. As the inorganic oxide carrier, usually, a porous inorganic oxide carrier is used, and specifically, for example, alumina, silica, silica-alumina, titania, alumina-titania and the like,
These can be used alone or in combination.
In the present invention, alumina, silica-alumina or alumina-titania is preferably used.

Further, as the desulfurization active metal, cobalt.
Examples thereof include molybdenum, nickel-molybdenum, nickel-cobalt-molybdenum, and the like, which can be used alone or in combination. These desulfurization active metals can be supported on the above-mentioned inorganic oxide support in the form of metal, oxide, sulfide or a mixture thereof.
As a method of supporting the metal, any known method such as an impregnation method or a coprecipitation method can be used. The amount of the active metal supported is preferably 5 to 70% by weight, and particularly preferably 30 to 50% by weight, based on the weight of the carrier. When the supported amount is within the above range, the desulfurization rate of cracked gasoline becomes high, which is preferable.

The catalyst in which desulfurization active metal is supported on the above-mentioned inorganic oxide carrier has an average pore diameter of 85 Å or more, preferably 90 Å or more. When this value is within the above range, the desulfurization rate of cracked gasoline is high and the hydrogenation rate of olefin is low, which is preferable in the effect of the present invention. From this point, the average pore diameter is more preferably in the range of 90 to 150Å. In addition, it is more preferable that the main peak of the pore size distribution of this average pore size is in this range. The surface area of the catalyst is 240 m ² /
It is preferably g or less. The desulfurization catalyst used in the desulfurization method of the present invention comprises a catalyst surface comprising a desulfurization active metal supported on the above-mentioned inorganic oxide carrier, and further comprises 30 to 30 parts by weight of the above catalyst.
It is made by accumulating 50% by weight of coke. By doing so, it is possible to suppress hydrogenation of olefins in the cracked gasoline fraction and obtain gasoline with a low sulfur content. Especially, the amount of coke accumulated is 30 to 50
By setting it as the weight%, the above effect can be further effectively exhibited. From this point, the accumulated amount of coke is 3
It is more preferable to set it to 0 to 40% by weight.

As a method of accumulating coke on the surface of the catalyst, any of a method of forcibly accumulating in a short time and a method of gradually accumulating over a long time can be preferably used. Further, in the present invention, an extraction catalyst usually used for hydrorefining petroleum can be used. Examples of the catalyst in which coke is accumulated on the surface of such a catalyst include direct desulfurization treatment, demetalization treatment,
Preference is given to waste catalysts used for indirect desulfurization treatment and the like.

In the present invention, the cracked gasoline fraction is desulfurized by using the above desulfurization catalyst. The cracked gasoline fraction used here is a heavy petroleum fraction, for example, vacuum gas oil or atmospheric residual oil. And the like, and the light catalytic cracking gasoline fraction, the heavy catalytic cracking gasoline fraction and the total catalytic cracking gasoline fraction obtained by distilling the catalytic cracking product, or the heavy petroleum fraction, for example, Light pyrolysis gasoline fraction, heavy pyrolysis gasoline fraction and total pyrolysis gasoline fraction obtained by thermally decomposing vacuum residual oil etc. and distilling oily pyrolysis products other than gas and coke are Can be mentioned. In particular, a fraction having a relatively high boiling point range has a high sulfur compound content and is easily desulfurized and is an effective raw material for desulfurization treatment, whereas a fraction having a relatively low boiling point range contains a sulfur compound. As a raw material to be desulfurized in the present invention, a heavy catalytic cracking gasoline fraction obtained by catalytically cracking a heavier raw material oil than a vacuum gas oil or the like is preferably used because the amount thereof is small and it is difficult to desulfurize.

Examples of the cracked gasoline fraction used in the present invention include those having a sulfur content of 5 to 3000 ppm by weight, an olefin content of 2 to 50% by volume, and an aromatic content of 2 to 50% by volume. . The hydrodesulfurization treatment conditions in the desulfurization method of the present invention include, for example, a temperature of 50 to 500.
℃, preferably 150-350 ℃, hydrogen partial pressure 1-200
MPa, preferably 1 to 50 MPa, further liquid hourly space velocity (LHSV) ^{1 to} 100 hr ^-1 , preferably 2 to 20 h.
r ⁻¹ . When the desulfurization temperature is within the above range,
The desulfurization rate and the olefin component content can be within the target range of the present invention without gasifying a part of the cracked gasoline fraction. Further, if the desulfurization treatment pressure is within the above range, the desulfurization rate and the olefin component content can be achieved without adversely affecting the catalyst life.

[0011]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The composition of the sulfur content, olefin content and other components in the feed oil and gasoline fraction was determined according to the following method. Sulfur content in feed oil and gasoline fractions, boiling point 180 ° C by AED gas chromatography analysis
The following sulfur content was identified and it calculated | required by integrating the sulfur content. Olefin content in feed oil and gasoline fraction All hydrocarbons having a boiling point of 180 ° C. or less were identified, and the olefin content was calculated by integrating the olefins, and the ratio of the total hydrocarbons was calculated.

Example 1 As a feedstock for catalytically cracked gasoline, a cracked gasoline fraction obtained by catalytically cracking a feedstock consisting of 100% desulfurized heavy oil was used. The properties are shown below. Sulfur content 52 ppm Composition olefin content 38.8 (vol%) Aromatic content 23.3 (vol%) Saturation content 37.9 (vol%) Further, as a desulfurization treatment catalyst, 8 wt% on an alumina carrier.
Of CoO and 30% by weight of MoO ₃ having an average pore size of 100 Å and a surface area of 200 m ² / g were used in a direct desulfurization unit under normal hydrodesulfurization conditions of atmospheric residue for about 1 year. Of spent catalyst was used. The amount of coke of the waste catalyst was 36.1% by weight based on the weight of the catalyst before being used in the above direct desulfurization device. Using the above catalyst, a hydrodesulfurization treatment of a cracked gasoline fraction was carried out under the following conditions. Reaction temperature 320 ° C. Reaction pressure 30 kg / cm ² G LHSV 8 hr ⁻¹ Hydrogen / oil ratio 80 Nm ³ / m ³ The sulfur content and olefin content of the obtained gasoline fraction were measured. It was 84% and the reduction rate of the olefin component was 8%.

Comparative Example 1 The hydrogenation treatment was carried out in the same manner as in Example 1 except that the spent catalyst used in Example 1 was reduced to 18% by weight by regeneration by coke combustion. It was As a result, the desulfurization rate of catalytically cracked gasoline feedstock is 100%,
The reduction rate of the olefin component was 40%. Comparative Example 2 Hydrogenation was carried out in the same manner as in Example 1 except that the catalyst used in Example 1 was further passed through atmospheric residual oil for 1 month to increase the coke amount to 60% by weight. Processed. As a result, the desulfurization rate of the catalytically cracked gasoline feedstock was 32%, and the reduction rate of the olefin component was 2%.

[0014]

As described in detail above, according to the desulfurization method of the present invention, it is possible to desulfurize cracked gasoline while suppressing the hydrogenation of olefins having a high octane number, and as a result, the octane number is high and the sulfur content is high. You can get less gasoline.

Claims (5)

[Claims] 1. A desulfurization catalyst obtained by accumulating 30 to 50% by weight of the catalyst weight of coke on the surface of a catalyst having an average pore diameter of 85 Å or more, which is obtained by supporting a desulfurization active metal on an inorganic oxide carrier. A method for desulfurizing a cracked gasoline distillate, which comprises desulfurizing a cracked gasoline distillate. 2. A surface area of a catalyst having an average pore diameter of 85Å or more, which is obtained by supporting a desulfurization active metal on an inorganic oxide carrier, has a surface area of 240.
The desulfurization method according to claim 1, which is at most m ² / g. 3. The desulfurization method according to claim 1, wherein the cracked gasoline fraction contains a sulfur compound and an olefin component. 4. The inorganic oxide carrier is alumina, silica,
Alumina or alumina titania.
The desulfurization method according to any one of 1. 5. The desulfurization active metal is cobalt molybdenum, nickel molybdenum or nickel cobalt.
The desulfurization method according to claim 1, which is molybdenum.