JP2007269902A - Method for hydrocracking wax - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for hydrocracking wax, with which both the yield of middle distillate and the yield of lubricating oil base are achieved at a high level and a gas oil fraction having an excellent low-temperature fluidity is produced. <P>SOLUTION: The method for hydrocracking wax comprises circulating wax from a first catalytic layer of a catalytic reaction part to a third catalytic layer in the presence of hydrogen in a fixed bed reactor equipped with a catalytic reaction part in which the first catalytic layer containing a first amorphous solid acid, a second catalytic layer containing zeolite and the third catalytic layer containing a second amorphous solid acid are arranged in this order. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for hydrocracking wax.

  In recent years, environmentally friendly clean liquid fuels, that is, fuels with a low content of sulfur and aromatic hydrocarbons have been demanded. Therefore, various studies have been conducted on a method for producing clean fuel, and one of them is the Fischer-Tropsch (FT) synthesis method. Since the FT synthesis method uses carbon monoxide and hydrogen as raw materials and can produce a liquid fuel base material having a high paraffin content and no sulfur content, it is expected in the future.

  In the FT synthesis method, a wax can be generated, but it is also possible to hydrocrack the wax and use the decomposition product as a clean fuel substrate. In this case, a middle distillate that can be used as a liquid fuel base material for gasoline or light oil is generally a target product. Therefore, a method for producing a liquid fuel base material that emphasizes middle distillate selectivity has been studied. For example, Patent Document 1 describes a method for producing a middle distillate from wax using a catalyst in which platinum is supported on amorphous silica alumina.

Further, it has been studied to convert normal paraffin contained in wax into isoparaffin by hydroisomerization and to use a product rich in isoparaffin as a lubricant base material. As a method for producing a lubricating oil base material from wax, Patent Document 2 discloses a method using a catalyst in which cobalt, molybdenum, nickel or the like is supported on amorphous silica alumina, and Patent Document 3 discloses a method using a zeolite catalyst. Is described.
JP-A-6-41549 International Publication No. 00/14183 Pamphlet International Publication No. 04/081157 Pamphlet

  By the way, in general, decomposition means a chemical reaction accompanied by a decrease in molecular weight, and isomerization means conversion to another compound while maintaining the molecular weight. Hydrocracking produces hydrocarbons with lower boiling points than the hydrocarbons being treated. On the other hand, in the hydroisomerization, the degree of branching is increased while maintaining the carbon number of the hydrocarbon to be treated. When wax is treated as a hydrocarbon to be treated and hydrocracked in the presence of a catalyst, the hydrocracking reaction and the hydroisomerization reaction proceed in a complicated manner.

  As an elemental technology for producing a liquid fuel base material and a lubricating oil base material from wax, conventionally, technical development of a catalyst used for this has been vigorously performed. However, hydrocracking involves reactions such as hydrogen transfer and carbon deposition in addition to hydroisomerization, and the reaction mechanism is complicated. For this reason, despite many years of research and development focused on catalysts, it was not always possible to obtain decomposition products having the desired characteristics.

  Specifically, the yield of the middle distillate, which is the target product in the hydrocracking of wax, could not be made sufficiently high. Also, problems such as insufficient low temperature fluidity of middle distillate, especially light oil distillate due to insufficient isomerization rate, and low yield of lubricant base material. Has occurred.

  The present invention has been made in view of such circumstances, and is capable of achieving both high yields of middle distillate and lubricating oil base material at a high level, and a light oil distillate excellent in low-temperature fluidity. It is an object of the present invention to provide a method for hydrocracking a wax that can be used to produce a wax.

  The method for hydrocracking wax according to the present invention comprises a first catalyst layer containing a first amorphous solid acid, a second catalyst layer containing zeolite, and a second amorphous solid acid. In the fixed bed reaction apparatus including the catalyst reaction section in which the third catalyst layers are arranged in this order, the wax is directed from the first catalyst layer of the catalyst reaction section to the third catalyst layer in the presence of hydrogen. It is characterized by being distributed.

  According to the present invention, both the yield of middle distillate and the isomerization rate from normal paraffin to isoparaffin are obtained by advancing hydrocracking reaction and hydroisomerization reaction in a catalytic reaction section having three catalyst layers. Can be achieved at a high level. Since the yield of middle distillate is sufficiently high, a liquid fuel substrate can be efficiently produced from wax. Moreover, since an isomerization rate can be made high enough, the low temperature fluidity | liquidity of the light oil fraction obtained and a lubricating oil fraction becomes high enough.

  In the present invention, the middle fraction means a fraction containing 90% by mass or more of hydrocarbon having a boiling point of 150 ° C. or higher and 360 ° C. or lower, and the lubricating oil fraction means 90% of hydrocarbon having a boiling point of higher than 360 ° C. This means a fraction containing at least mass%. The light oil fraction means a fraction that is a part of the middle fraction and contains 90% by mass or more of hydrocarbons having a boiling point of 260 ° C. or higher and 360 ° C. or lower.

  Moreover, according to this invention, it becomes possible to manufacture a lubricating oil base material with a sufficiently high yield. Lubricating oil base materials are generally manufactured by performing a dewaxing treatment that reduces the content of the wax mainly composed of normal paraffin contained in the lubricating oil fraction of decomposition products. Since the lubricating oil fraction contained in the decomposition product obtained by the method of the present invention has a high isoparaffin content by hydroisomerization, there is little normal paraffin removed by the dewaxing treatment, and the lubricating oil base material High yields are achieved.

  In the present invention, the second catalyst layer preferably contains USY zeolite (ultra-stabilized Y-type zeolite) as zeolite. This is because when the second catalyst layer contains USY zeolite, hydrocracking can be performed more efficiently than in the case of containing other types of zeolite.

  Moreover, it is preferable that the 1st and 3rd catalyst layer contains 1 or more types chosen from a silica alumina, a silica zirconia, and a silicoaluminophosphate as a 1st or 2nd non-crystalline solid acid, respectively. When the first or second non-crystalline solid acid contains the non-crystalline solid acid, the isomerization rate can be further improved as compared with the case where the non-crystalline solid acid other than the above is contained. is there.

  Each of the first and third catalyst layers contains one or more metals selected from platinum and palladium supported on the first or second amorphous solid acid, and the second catalyst layer is made of zeolite. It is preferable to contain one or more metals selected from supported platinum and palladium. If a catalyst in which platinum and / or palladium is supported on an amorphous solid acid or zeolite is used in the first and third catalyst layers and the second catalyst layer, a catalyst in which these metals are not supported is used. This is because hydrocracking can be performed more efficiently than when it is used.

  The wax used in the present invention is preferably obtained by Fischer-Tropsch synthesis. The wax obtained by the FT synthesis method is substantially free from environmentally hazardous substances such as sulfur and aromatic hydrocarbons. For this reason, when the raw material wax is obtained by the FT synthesis method, it becomes possible to produce a middle distillate and a lubricant base material in which the content of environmentally hazardous substances is sufficiently reduced.

  According to the present invention, there is provided a method for hydrocracking wax capable of producing a light oil fraction excellent in low-temperature fluidity while achieving both high yield of middle distillate and yield of lubricating oil base material. Provided.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view showing a preferred example of a fixed bed reactor according to an embodiment of the present invention. The fixed bed reactor shown in FIG. 1 performs hydrocracking and hydroisomerization in a reaction tower 10, and a catalytic reaction section 1 is arranged in the reaction tower 10.

  A line L1 for supplying hydrogen into the reaction tower 10 is connected to the top of the reaction tower 10, and a line L2 for supplying wax to the upstream side of the connection portion of the line L1 with the reaction tower 10 is connected. Are connected. As a result, it is possible to introduce wax into the reaction tower 10 together with hydrogen and pass the catalyst reaction unit 1 to hydrocrack and hydroisomerize the wax. A line L3 for extracting a decomposition product is connected to the bottom of the reaction tower 10.

  Although FIG. 1 shows an example of a reactor in which the hydrogen supply line L1 and the wax supply line L2 are joined, the hydrogen supply line L1 and the wax supply line L2 are separately connected to the reaction tower 10 respectively. May be. Further, the flow direction of the wax is preferably the direction from the top side to the bottom side of the reaction tower 10 as shown in FIG.

  The catalyst reaction unit 1 includes a catalyst layer 1a (first catalyst layer) containing a first amorphous solid acid, a catalyst layer 1b (second catalyst layer) containing zeolite, and a second amorphous crystal. And a catalyst layer 1c (third catalyst layer) containing a basic solid acid. In the catalyst reaction part 1, these catalyst layers are arrange | positioned from the upstream to the downstream in order of the catalyst layer 1a, the catalyst layer 1b, and the catalyst layer 1c. The first and second amorphous solid acids may be the same or different.

  The catalyst containing the non-crystalline solid acid constituting the catalyst layer 1a and the catalyst layer 1c (hereinafter referred to as “non-crystalline solid acid catalyst”) may be any catalyst having hydrogenation resolution and hydroisomerization ability. Although not particularly limited, the carrier contains at least one amorphous solid acid selected from silica alumina, silica zirconia, alumina boria, silica titania, silica magnesia, kaolinite, aluminophosphate and silicoaluminophosphate. A catalyst is preferably used, and a catalyst containing at least one amorphous solid acid selected from silica alumina, silica zirconia and silicoaluminophosphate is more preferably used.

  Further, as the non-crystalline solid acid catalyst, a catalyst in which a metal of group VI of the periodic table and / or a metal of group VIII is supported on the above support is preferable. Specific examples of the Group VI A metal include chromium, molybdenum, and tungsten. Specific examples of the Group VIII metal include cobalt, nickel, rhodium, palladium, iridium, and platinum. Among these, palladium and / or platinum are preferable, and platinum is more preferable. The amount of metal supported on the support is not particularly limited, but is preferably 0.01 to 2% by mass with respect to the support. When the metal supported on the support is palladium and / or platinum, preferably 0.05 It is -2 mass%. The metals contained in the non-crystalline solid acid catalyst constituting the catalyst layer 1a and the catalyst layer 1c may be the same or different.

  The amorphous solid acid catalyst may further contain a binder for carrier molding. The binder is not particularly limited, but preferred binders include alumina or silica. The shape of the carrier is not particularly limited, and may be a granular shape, a cylindrical shape (pellet), or the like. In addition, the binder which the amorphous solid acid catalyst which comprises the catalyst layer 1a and the catalyst layer 1c contains may be the same, or may differ.

  The catalyst containing the zeolite constituting the catalyst layer 1b (hereinafter referred to as “zeolite-based catalyst”) is not particularly limited as long as it has hydrogenation resolution and hydroisomerization ability. It is preferable to use a catalyst containing one or more types of zeolite selected from HY zeolite, mordenite, β zeolite and Ω zeolite, and among these, it is particularly preferable to use a catalyst containing USY zeolite. When the support of the zeolitic catalyst includes USY zeolite, the proportion of USY zeolite in the support is not particularly limited, but from the viewpoint of suppressing the lightening of the decomposition products, the proportion of USY zeolite is the total amount of the support. As a standard, 15 mass% or less is preferable, and 5 mass% or less is more preferable.

  The molar ratio of silica / alumina in USY zeolite is not particularly limited, but is preferably 20 to 200, more preferably 25 to 100, and most preferably 30 to 60. The average particle size of USY zeolite is preferably 1.0 μm or less, more preferably 0.5 μm or less. In addition, when the average particle diameter of USY zeolite is larger than 1.0 μm, the obtained decomposition product tends to be lightened.

  Further, the zeolite-based catalyst is preferably a catalyst in which a metal of group VI of the periodic table and / or a metal of group VIII is supported on the above support. Specific examples of the Group VI A metal include chromium, molybdenum, and tungsten. Specific examples of the Group VIII metal include cobalt, nickel, rhodium, palladium, iridium, and platinum. Among these, palladium and / or platinum are preferable, and platinum is more preferable. The amount of metal supported on the support is not particularly limited, but is preferably 0.01 to 2% by mass with respect to the support. When the metal supported on the support is palladium and / or platinum, preferably 0.05 It is -2 mass%.

  The zeolitic catalyst may further contain a binder for carrier molding. The binder is not particularly limited, but preferred binders include alumina or silica. The shape of the carrier is not particularly limited, and may be a granular shape, a cylindrical shape (pellet), or the like.

  The ratio of the amount (volume) of the first and second amorphous solid acid catalysts and the zeolite-based catalyst in the catalyst reaction unit 1 is not particularly limited, but the amount of the zeolite-based catalyst constituting the catalyst layer 1b is not limited. If it is 1 volume part, it is preferable that the filling amount of the 1st non-crystalline solid acid catalyst which comprises the catalyst layer 1a is 0.5-3 volume part. When the filling amount of the first amorphous solid acid catalyst is out of the range of 0.5 to 3 parts by volume, the yield of the middle distillate tends to be lower than that in the range.

  On the other hand, when the filling amount of the zeolitic catalyst constituting the catalyst layer 1b is 1 part by volume, the filling amount of the third amorphous solid acid catalyst constituting the catalyst layer 1c is 0.5 to 2.0 parts by volume. It is preferable that When the filling amount of the third non-crystalline solid acid catalyst is less than 0.5, the yield of the middle distillate tends to be high, but the low-temperature fluidity tends to be insufficient. If it exceeds, the low-temperature fluidity of the middle distillate is improved, but the yield tends to be low.

  The wax introduced into the reaction tower 10 via the hydrogen supply line L1 is, for example, a petroleum or synthetic wax containing 30% by mass or more of normal paraffin having 15 to 100 carbon atoms, preferably 20 to 60 carbon atoms. Is mentioned. Examples of petroleum wax include slack wax and micro wax, and examples of synthetic wax include so-called FT wax produced by FT synthesis. From the viewpoint of reducing environmental burden, FT wax is particularly suitable as the wax.

  Although the hydrocracking treatment conditions in the reaction tower 10 are not particularly limited, the reaction temperature is preferably 250 to 370 ° C, more preferably 280 to 330 ° C. If the reaction temperature is less than 250 ° C., hydrocracking tends not to proceed sufficiently. On the other hand, when the reaction temperature exceeds 370 ° C., the yield of the middle distillate of hydrocracking decreases, and the cracked product tends to be colored.

The liquid space velocity in the reaction tower 10 is preferably 0.1 to 10.0 h ⁻¹ , more preferably 0.2 to 3.0 h ⁻¹ . If the liquid space velocity is less than 0.1 h ⁻¹ , the yield of middle distillate tends to decrease. On the other hand, when the liquid space velocity exceeds 10.0 h ⁻¹ , hydrogenolysis tends not to proceed sufficiently.

  The reaction pressure in the reaction tower 10 is not particularly limited, but the hydrogen partial pressure is preferably 0.5 to 10.0 MPa, more preferably 2.0 to 7.0 MPa. Furthermore, the hydrogen / oil ratio in the reaction tower 10 is preferably 150 to 1200 NL / L, more preferably 200 to 700 NL / L.

  The cracked products transferred in line L3 are usually naphtha (fractions with a boiling point of less than 145 ° C.), middle fractions (fractions with a boiling point of 145 to 360 ° C.) and lubricating oil fractions (fractions having a boiling point of more than 360 ° C. The base material according to various uses can be obtained by fractionating these fractions.

  From the viewpoint of low temperature startability or low temperature drivability, the pour point of the middle distillate used as the liquid fuel substrate is preferably low. In particular, the pour point of the light oil fraction (fraction having a boiling point of 260 to 360 ° C.) is preferably −10 ° C. or less, more preferably −15 ° C. or less, still more preferably −20 ° C. or less, and even more preferably −25. It is below ℃. The pour point here means a pour point measured in accordance with JIS K 2269-1987 “Pour point of crude oil and petroleum products and cloud point test method of petroleum products”.

  If the lubricating oil fraction fractionated from the cracked product is not sufficiently low, it is dewaxed to obtain a lubricating base oil having the desired pour point. Dewaxing can be performed by a conventional method such as a solvent dewaxing method or a catalytic dewaxing method. Among these, the solvent dewaxing method generally uses a mixed solvent of MEK and toluene, but may use a solvent such as benzene, acetone, MIBK or the like. Dewaxing using a solvent is preferably performed under conditions of a solvent / oil ratio of 1 to 6 times and a filtration temperature of -5 to -45 ° C, preferably -10 to -40 ° C. The wax removed here can be reintroduced into the reaction tower 10 as slack wax.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

<Preparation of non-crystalline solid acid catalyst>
(Catalyst A-1)
40 parts by mass of boehmite (alumina) was added as a binder to 60 parts by mass of amorphous silica alumina having an alumina content of 14% by mass, a pore volume of 0.68 ml / g, and an average particle diameter of 5 μm. By thoroughly kneading a mixture of amorphous silica alumina and boehmite, forming a cylindrical carrier having a diameter of 1.6 mm and a length of about 2 mm, and firing it (firing temperature: 500 ° C., holding time: 3 hours) An amorphous solid acid was obtained. This amorphous solid acid was impregnated with an aqueous solution of dichlorotetraammineplatinum (II), and 0.5 mass% of platinum was supported on the amorphous solid acid. The catalyst A-1 was obtained by drying and baking this (calcination temperature: 500 degreeC, holding time: 1 hour).

(Catalyst A-2)
Boehmite (50 parts by mass) was added as a binder to 50 parts by mass of aluminophosphate (SAPO-11) composed of 41% by mass of alumina, 56% by mass of phosphorus pentoxide and 3% by mass of silica. A mixture of aluminophosphate and boehmite is kneaded well, then molded into a cylindrical shape with a diameter of 1.6 mm and a length of about 2 mm, and then fired (firing temperature: 500 ° C., holding time: 3 hours) to be amorphous. Acid solid acid was obtained. This amorphous solid acid was impregnated with an aqueous solution of dichlorotetraammineplatinum (II), and 0.5 mass% of platinum was supported on the amorphous solid acid. The catalyst A-2 was obtained by drying and baking this (calcination temperature: 500 degreeC, holding time: 1 hour).

<Preparation of zeolite catalyst>
(Catalyst Z-1)
97 parts by mass of boehmite was added as a binder to 3 parts by mass of USY zeolite having a silica / alumina molar ratio of 38 and an average particle diameter of 0.8 μm. A mixture consisting of USY zeolite and boehmite is well kneaded, then molded into a cylindrical shape with a diameter of 1.6 mm and a length of about 2 mm, and this is calcined (calcination temperature: 500 ° C., holding time: 3 hours). The carrier to be obtained was obtained. The carrier was impregnated with an aqueous solution of dichlorotetraammine platinum (II), and 0.6% by mass of platinum was supported on the carrier. This was dried and calcined (calcining temperature: 500 ° C., holding time: 1 hour) to obtain catalyst Z-1.

Example 1
<Hydrogen hydrocracking>
Next, 100 ml of catalyst A-1 is filled as catalyst layer 1a of the fixed bed reactor shown in FIG. 1, 100 ml of catalyst Z-1 is filled as catalyst layer 1b, and 100 ml of catalyst A-1 is filled as catalyst layer 1c. Was hydrocracked. Prior to the hydrocracking of the wax, each catalyst was reduced by holding the inside of the catalyst reaction section 1 in the presence of hydrogen at a temperature of 340 ° C. for 2 hours.

The raw material wax was an FT wax having a boiling point exceeding 360 ° C., and this raw material wax was supplied from the top of the reaction tower 10 at a rate of 200 ml / h. Moreover, hydrogen was supplied from the top of the raw material wax at a hydrogen / oil ratio of 590 NL / L. The pressure in the reaction tower 10 was adjusted with a back pressure valve so as to be constant at an inlet pressure of 4 MPa. The hydrocracking temperature in the reaction tower 10 was 312 ° C. when adjusted so that the cracking rate of the wax was 80% by mass. Here, the decomposition rate of wax means a decomposition rate defined by the following formula (1). In the following formula (1), “the total mass of the cracked product” is the total mass of the product oil and product gas obtained by hydrocracking, and “the mass of the fraction having a boiling point of less than 360 ° C.” Is the mass of a fraction having a boiling point of less than 360 ° C. contained in the decomposition product.

  Next, a kerosene fraction (boiling point: 145 to 260 ° C.), a light oil fraction (boiling point: 260 to 360 ° C.) and a lubricating oil fraction (boiling point) are obtained by atmospheric distillation of the obtained decomposition product. Fractions exceeding 360 ° C.), and the yield of each fraction was determined based on the mass of the raw material wax. Table 1 shows the yield of the middle distillate (the fraction having a boiling point of 145 to 360 ° C.) obtained by summing the yields of the kerosene fraction and the light oil fraction, and the light oil fraction measured in accordance with JIS K 2269-1987. The measurement result of the pour point is shown.

  Also, a lubricating oil base was produced by solvent dewaxing of the lubricating oil fraction. A methyl ethyl ketone-toluene mixed solvent was used as a solvent, and the conditions were a solvent / oil ratio of 4 times and a filtration temperature of -20 ° C. Table 1 shows the yield of the lubricant base material based on the mass of the raw material wax.

(Example 2)
Wax hydrocracking, solvent dewaxing, and various measurements were performed in the same manner as in Example 1 except that 100 ml of catalyst A-2 was used instead of catalyst A-1 as catalyst layer 1c. The hydrocracking temperature in the reaction tower 10 was 310 ° C. when the wax cracking rate was adjusted to 80% by mass. The measurement results are shown in Table 1.

(Comparative Example 1)
The catalyst hydrocracking, solvent dewaxing and various measurements were carried out in the same manner as in Example 1 except that 100 ml of catalyst Z-1 was filled as the catalyst layer 1b and the catalyst layer 1a and catalyst layer 1c were provided. went. The hydrocracking temperature in the reaction tower 10 was 317 ° C. when the wax cracking rate was adjusted to 80 mass%. The measurement results are shown in Table 1.

(Comparative Example 2)
Hydrocracking of wax in the same manner as in Example 1 except that 100 ml of catalyst A-1 as catalyst layer 1a and 100 ml of catalyst Z-1 as catalyst layer 1b were filled and catalyst layer 1c was not provided. Solvent dewaxing and various measurements were performed. The hydrocracking temperature in the reaction tower 10 was 314 ° C. when the wax cracking rate was adjusted to 80 mass%. The measurement results are shown in Table 1.

(Comparative Example 3)
Hydrocracking of wax in the same manner as in Example 1 except that 100 ml of catalyst Z-1 as catalyst layer 1b and 100 ml of catalyst A-1 as catalyst layer 1c were filled and catalyst layer 1a was provided. Solvent dewaxing and various measurements were performed. The hydrocracking temperature in the reaction tower 10 was 315 ° C. when the wax cracking rate was adjusted to 80% by mass. The measurement results are shown in Table 1.

  As described above, by performing hydrocracking in the catalytic reaction section having a three-layer structure in which an amorphous solid acid catalyst, a zeolite-based catalyst, and an amorphous solid acid catalyst are arranged in this order, It can be seen that both the yield and the yield of the lubricant base material can be achieved at a high level, and a light oil fraction excellent in low-temperature fluidity can be obtained.

It is explanatory drawing which shows an example of the fixed bed reaction apparatus used by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Catalyst reaction part, 1a ... Catalyst layer (1st catalyst layer), 1b ... Catalyst layer (2nd catalyst layer), 1c ... Catalyst layer (3rd catalyst layer), 10 ... Reaction tower (fixed bed reaction) apparatus).

Claims (5)

  The first catalyst layer containing the first amorphous solid acid, the second catalyst layer containing the zeolite, and the third catalyst layer containing the second amorphous solid acid are arranged in this order. In the fixed bed reactor comprising the catalytic reaction section, the wax is circulated from the first catalyst layer of the catalytic reaction section toward the third catalyst layer in the presence of hydrogen. Hydrocracking method.   2. The wax hydrocracking method according to claim 1, wherein the second catalyst layer contains USY zeolite.   The method for hydrocracking wax according to claim 1 or 2, wherein the first and third catalyst layers each contain one or more selected from silica alumina, silica zirconia, and silicoaluminophosphate. .   The first and third catalyst layers each contain one or more metals selected from platinum and palladium supported on the first or second amorphous solid acid, and the second catalyst layer includes The method for hydrocracking a wax according to any one of claims 1 to 3, comprising at least one metal selected from platinum and palladium supported on zeolite. The wax hydrocracking method according to any one of claims 1 to 4, wherein the wax is obtained by Fischer-Tropsch synthesis.

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