Guard catalyst layer, hydrogen treatment device for hydrocarbon oil, and hydrogen treatment method for hydrocarbon oil

Abstract

To provide a guard catalyst layer which has high ability of suppressing accumulation of scale and generation of a drift in hydrogen treatment of hydrocarbon oil.SOLUTION: There is provided a guard catalyst layer formed by laminating at least a first layer including a first layer catalyst, and a second layer including a second layer catalyst, a cross section of each of the first layer catalyst and the second layer catalyst comprises: a region which is closed and formed by alternately coupling, a plurality of recessed edges which is formed of a curve becoming a hollow toward a center side of a catalyst cross section or a straight line which is refracted to a center side of a catalyst cross section, and salient edges whose number is equal to that of the recessed edges and which are formed of a curve protruded to an opposite side of the center of the catalyst cross section, or a straight line which is refracted to an opposite side of the center of the catalyst cross section. A hollow part exists in the center of the cross section of the first layer catalyst, and the second layer catalyst has a bimodal pore distribution and has pore volume of 0.8 to 1.4 ml / g.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a guard catalyst for efficiently removing impurities (hereinafter also referred to as "scale") from hydrocarbon oils, particularly heavy hydrocarbon oils (hereinafter also referred to as "heavy oils"), in the presence of hydrogen, as well as a hydrotreating apparatus for hydrocarbon oils and a hydrotreating method for hydrocarbon oils using the same. [Background technology]

[0002] In the hydrotreating process of hydrocarbon oils, impurities (scale) such as iron rust particles contained in the feedstock oil accumulate on the catalyst bed, causing drift and pressure differences, which can deactivate the catalyst or hinder operation at the desired pressure, so it is necessary to remove the impurities contained in the feedstock oil. The upstream part of the hydrotreating unit is filled with a guard catalyst whose main purpose is to remove impurities and suppress drift while maintaining hydrogenation activity, but in order to cope with the recent trend toward heavier feedstock oils and the increase in the amount of heavy oil processed in hydrotreating units, guard catalyst systems with higher descaling and drift suppression capabilities than ever before are required.

[0003] Various attempts have been made to suppress the deposition of scale and the occurrence of drift in the catalyst layer. Patent Document 1 describes a catalyst in which an active component is supported on a carrier, with the aim of providing a guard catalyst for hydrodesulfurization to remove impurities deposited in the upper catalyst bed of a reaction tower, eliminate the pressure difference, maintain the catalytic activity in the catalyst bed, and ultimately maintain stable operation, and in which the dispersibility of the active metal, a metal of Group 7b of the periodic table, is 2 to 30% in terms of CO adsorption rate.

[0004] Patent Document 2 describes a catalyst carrier, for example, a sintered catalyst having a specific surface area of ​​5 m2, which is made of 3 to 10% by weight of boria, 4 to 19% by weight of silica, and the remainder Al2O3, and is calcined at a temperature range of 1000 to 1500°C. 2The present invention discloses a hydrotreating catalyst for descaling, which is characterized in that the catalyst comprises a porous inorganic oxide support having an apparent porosity of 20 to 70%, a pore volume of 0.1 ml / g or more for pores with diameters of 40 angstroms or more, and an apparent porosity of 20 to 70%, and which supports, in an amount of preferably 0.1 to 4% by weight, an oxide or sulfide of at least one metal selected from the group consisting of metals of groups V, VI, and VIII of the periodic table.

[0005] In the following Patent Document 3, a descaling agent and catalyst with a surface area of ​​1 m is packed upstream of a conventional desulfurization or demetalization catalyst. 2 The catalyst has a pore volume of 0.1 ml / g or more and a pore diameter of 10 μm or more. The shape may be spherical or hollow macaroni-shaped, wheel-shaped, petal-shaped, etc., and the particle size is preferably 1 mm to 5 cm in the longest direction. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 08-173808 [Patent Document 2] Japanese Patent Application Publication No. 05-184941 [Patent Document 3] Japanese Patent Application Publication No. 02-305891 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the combination of existing guard catalysts and demetalization catalyst grading alone does not provide sufficient descaling and drift suppression capabilities, and operational problems may occur due to the accumulation of impurities (a type of scale) in the catalyst layer. For example, the accumulation of impurities in the catalyst layer may cause drift in the catalyst layer, which may lead to blockage of the catalyst layer or catalyst deterioration due to increased coke generation associated with the appearance of hot spots caused by the drift. One type of impurity (scale) is, for example, iron rust particles, and the iron sulfide generated by the sulfurization of these particles promotes coke generation and also accelerates coke accumulation. Therefore, it is important to suppress the accumulation of impurities in the catalyst layer in order to extend the operation period of the device and the catalyst life.

[0008] An object of the present invention is to provide a guard catalyst layer which is highly capable of suppressing the deposition of scale and the generation of drift flow, and a method for hydrotreating heavy hydrocarbon oil using the same. [Means for solving the problem]

[0009] As a result of intensive research conducted by the inventors to solve the above problems, they discovered that a guard catalyst stacking system, in which a catalyst having a specific shape is packed upstream and a catalyst having a specific pore volume is packed downstream of the catalyst having a specific shape, exhibits particularly excellent descaling and drift suppression capabilities.

[0010] The present invention relates to, for example, the following [1] to

[10] . [1] The guard catalyst layer of the present invention is A guard catalyst layer including at least a first layer including a first layer catalyst and a second layer including a second layer catalyst, the first layer catalyst and the second layer catalyst each independently include an inorganic oxide support and a metal component supported on the inorganic oxide support; the first catalyst is cylindrical, and a cross section of the first catalyst perpendicular to the long axis direction has a closed region formed by alternatingly connecting a plurality of first concave edges each consisting of a curve concave toward the center of the cross section of the first catalyst or a straight line bent toward the center of the cross section of the first catalyst, and a first convex edge of the same number as the first concave edges each consisting of a curve protruding on the side opposite to the center of the cross section of the first catalyst or a straight line bent on the side opposite to the center of the cross section of the first catalyst, A hollow portion is present at the center of the cross section of the first catalyst, the second layer catalyst is columnar, and a cross section of the second layer catalyst perpendicular to the long axis direction is formed by alternately connecting a plurality of second concave edges each consisting of a curve recessed toward the center of the cross section of the second layer catalyst or a straight line bent toward the center of the cross section of the second layer catalyst, and a second convex edge of the same number as the second concave edges each consisting of a curve protruding on the side opposite to the center of the cross section of the second layer catalyst or a straight line bent on the side opposite to the center of the cross section of the second layer catalyst, the second layer catalyst has a bimodal pore distribution; The second layer catalyst has a pore volume of 0.8 to 1.4 ml / g as measured by a water pore filling method. A guard catalyst layer.

[0011] In this way, the first layer catalyst has a characteristic shape in cross section, the second layer catalyst has a characteristic shape in cross section, and the second layer catalyst has a characteristic pore distribution and a large pore volume, making it possible to provide a guard catalyst layer that is highly capable of suppressing scale deposition and the generation of drift.

[0012] [2] The guard catalyst layer according to [1], wherein a cross section of the first catalyst layer has 3 to 14 of the first concave edges and the first convex edges. That is, in order to exert the ability to suppress the deposition of scale and the generation of drift current, it is preferable that the number of concave and convex edges is 3 to 14.

[0013] [3] The cross section of the first catalyst is Four of the first concave edges with a radius of curvature of R1 and an arc length of L1 and four of the first convex edges with a radius of curvature of R2 and an arc length of L2 are alternately connected to form a closed region. The guard catalyst layer according to [2], characterized in that it satisfies the conditions of 1.5 < R1 / R2 < 10 and 0.5 < L1 / L2 < 3.0.

[0014] In this way, by imposing predetermined conditions on the radius of curvature and arc length of the first concave edge and the first convex edge that make up the cross-section of the first layer catalyst, when the guard catalyst is filled in the hydrogenation treatment apparatus, when the hydrocarbon oil is flowed in the long axis direction, the descaling ability to moderately capture scale in the grooves (concave surfaces) on the surface of the outer edge of the first layer catalyst can be enhanced, and the fluidity (liquid diffusibility) of the hydrocarbon oil can be improved.

[0015] [4] In the cross-section of the first layer catalyst, when the radius of the circumscribed circle circumscribing the hollow portion is defined as R3 and the radius of the circumscribed circle circumscribing the first layer catalyst is defined as R4, The guard catalyst layer according to any one of [1] to [3], characterized in that it satisfies the condition of 0.2 < R3 / R4 < 0.8.

[0016] In this way, by imposing predetermined conditions on the relationship between the hollow portion and the radius of the circumscribed circle of the cross-section of the first layer catalyst, the fluidity and scale capture ability of the hydrocarbon oil can be increased while maintaining the mechanical strength.

[0017] [5] The first layer catalyst has a diameter of the circumscribed circle circumscribing the first layer catalyst in the cross-section of 2 to 15 mm, a length in the long axis direction of 7 to 30 mm, and a pore volume (PV) measured by the water pore filling method of 0.5 to 1.4 ml / g. The guard catalyst layer according to any one of [1] to [4].

[0018] [6] The second layer catalyst is a guard catalyst layer according to any one of the above [1] to [5], characterized in that the diameter of a circumscribing circle circumscribing the second layer catalyst in the cross section is 1.5 to 10 mm, and the length in the major axis direction is 3 to 15 mm.

[0019] [7] A hydrotreating treatment apparatus for hydrocarbon oil, comprising a guard catalyst layer according to any one of [1] to [6] above.

[0020] [8] A method for hydrotreating a hydrocarbon oil, comprising a hydrotreating step of contacting the hydrocarbon oil with any one of the guard catalyst layers described above in [1] to [6].

[0021] [9] The hydrocarbon oil is a heavy hydrocarbon oil having a density of 0.90 to 1.05 g / cm 3 The method for hydrotreating a hydrocarbon oil according to [8] above, wherein the sulfur content is 1 to 6 mass% and the hydrocarbon oil contains 80 mass% or more of components having a boiling point of 360°C or higher.

[0022]

[10] The hydrotreating step is carried out under a hydrogen partial pressure of 5.0 to 20 MPa, a reaction temperature of 350 to 420°C, and a liquid hourly space velocity of 0.1 to 0.5 h -1 The method for hydrotreating a hydrocarbon oil according to [8] or [9] above, wherein the hydrotreating process is carried out under the conditions of Effect of the Invention

[0023] According to the present invention, it is possible to realize high descaling ability and flow drift suppression ability in the hydrotreating of hydrocarbon oils, particularly heavy oils. By suppressing the generation of hot spots and catalyst deterioration due to flow drift and suppressing the generation of pressure differences, it is possible to stabilize the catalyst life and to deal with the heavier feedstock oil.

[0024] The guard catalyst layer of the present invention can be widely used in hydrotreating and hydrocracking treatment devices for not only heavy oil feed but also kerosene, diesel, and vacuum gas oil (VGO). In addition, the catalysts (first layer catalyst, second layer catalyst) used in the present invention have a large pore volume themselves, and therefore are characterized in that they can not only capture scale on the outer surface of the catalyst, but also capture metal components such as Ni and V dissolved in the feed oil inside the catalyst. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a diagram showing a cross section of a first layer catalyst included in a guard catalyst layer according to the present embodiment. [Diagram 2] FIG. 2 is a diagram showing a cross section of a first layer catalyst included in a guard catalyst layer according to this embodiment. [Diagram 3] FIG. 3 is a diagram showing a cross section of a first layer catalyst included in a guard catalyst layer according to this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these descriptions in any way. In this specification, the numerical range expressed as "x to y" means "not less than x and not more than y."

[0027] The present invention provides a guard catalyst layer for use in a hydrotreating treatment device for a hydrocarbon oil and a method for hydrotreating a hydrocarbon oil. The guard catalyst layer is usually used in the most upstream part of the hydrotreating treatment device, but a filter part may be appropriately installed further upstream of the guard catalyst layer as necessary.

[0028] The guard catalyst layer packed according to the present invention can be used for the hydrotreating of general hydrocarbon oils, but is particularly suitable for the hydrotreating of heavy oil, which contains a large amount of impurities and is prone to operational problems such as scale generation and uneven flow. A catalyst system for hydrotreating heavy oil is usually composed of a guard catalyst section, a demetalization section, a transition section, and a desulfurization section stacked from the upstream section.

[0029] The guard catalyst layer according to the present invention is formed by laminating at least a first layer containing a first layer catalyst and a second layer containing a second layer catalyst. The guard catalyst layer according to the present invention is mainly used for hydrotreating hydrocarbon oils. The first layer catalyst can be the same as a conventional hydrotreating catalyst used for hydrotreating hydrocarbon oils, especially heavy oils, except that it has a specific cross-sectional shape. The second layer catalyst can be the same as a conventional hydrotreating catalyst used for hydrotreating hydrocarbon oils, especially heavy oils, except that it has a specific cross-sectional shape, a pore volume within a specific range, and a specific pore distribution. Therefore, the first layer catalyst and the second layer catalyst each usually contain an inorganic oxide support mainly composed of alumina, and a metal component supported on the inorganic oxide support.

[0030] <Inorganic oxide carrier> The inorganic oxide support is a support containing alumina (more specifically, γ-alumina) as a main component, and may optionally contain a support additive component. The inorganic oxide support contains aluminum in an amount of preferably 60 to 100 mass %, more preferably 65 to 100 mass %, based on the oxide (Al2O3).

[0031] Such inorganic oxide supports are mainly composed of alumina within the above composition range, and therefore have a high specific surface area, a large pore volume, high pressure resistance and abrasion resistance, as well as high productivity, such as suitability for extrusion molding, and are therefore suitable as supports for hydrotreating catalysts.

[0032] Examples of the carrier additive component include at least one oxide selected from the group consisting of phosphorus oxide, silica, titania, zirconia, boria, and magnesia, which usually form a composite oxide with alumina (e.g., alumina-silica, alumina-titania). The inorganic oxide support may further contain minerals such as zeolite, talc, kaolinite, and montmorillonite.

[0033] (Method of producing inorganic oxide support) The inorganic oxide support mainly composed of alumina can be prepared by various methods, but it is common to obtain the support mainly composed of alumina by calcining aluminum hydroxide. For example, the inorganic oxide support mainly composed of alumina may be obtained by preparing a support precursor mainly composed of alumina hydrate from an acidic aluminum salt and a basic aluminum salt by a neutralization method, and calcining the carrier, or by calcining a commercially available aluminum hydroxide powder.

[0034] Acidic aluminum salts are water-soluble salts, examples of which include aluminum sulfate, aluminum chloride, aluminum acetate, and aluminum nitrate. Basic aluminum salts are also water-soluble salts, examples of which include sodium aluminate and potassium aluminate. Commercially available aluminum hydroxide powders include CATAPAL and PURAL from SASOL and VERSAL from UOP.

[0035] The raw material of the carrier additive component can be added in various steps in the production of the inorganic oxide carrier. For example, the carrier additive component raw material can be added by making the carrier additive component raw material coexist during neutralization of the acidic aluminum salt and the basic aluminum salt, adding the carrier additive component raw material to the carrier precursor containing aluminum hydroxide as the main component in the aging process, adding the carrier additive component raw material to the alumina hydrate in the kneading process of the alumina hydrate, or impregnating the obtained alumina carrier with the carrier additive component raw material by a pore filling method.

[0036] Examples of phosphorus-containing carrier additive raw materials include phosphate compounds that generate phosphate ions or phosphite ions in water, such as ammonium phosphate, potassium phosphate, sodium phosphate, phosphoric acid, and phosphorous acid.

[0037] Examples of the carrier additive raw material containing silicon include sodium silicate, silicon tetrachloride, silica powder, silica sol, and silica gel. Sodium silicate is particularly preferred because it is inexpensive.

[0038] Examples of titanium-containing carrier additive raw materials include titanium tetrachloride, titanium trichloride, titanium sulfate, titanyl sulfate, titanium nitrate, titanium hydroxide gel, metatitanic acid, and titania powder. Titanium sulfate and titanyl sulfate are particularly preferred because they are inexpensive.

[0039] Examples of the carrier additive raw material containing zirconium include zirconium sulfate, zirconium acetate, zirconium nitrate, zirconium oxychloride, zirconium carbonate, and zirconia powder.

[0040] Examples of carrier additive raw materials containing boron include boric acid, ammonium borate, sodium borate, and aluminum borate. Examples of magnesium-containing carrier additive component raw materials include magnesium oxide, magnesium hydroxide, and magnesium sulfate.

[0041] In addition, water and at least one organic additive selected from organic acids and sugars may be added to the obtained alumina hydrate slurry or powder, if necessary, and then the alumina hydrate may be aged. Examples of organic acids include citric acid, malic acid, tartaric acid, gluconic acid, acetic acid, ethylenediaminetetraacetic acid (EDTA), and diethylenetriaminepentaacetic acid (DTPA). Examples of sugars include monosaccharides, disaccharides, and polysaccharides.

[0042] The carrier precursor containing the alumina hydrate and, if necessary, any optional components, is heated and kneaded, for example, in a steam-jacketed twin-arm kneader, to form a moldable kneaded product, which is then molded by extrusion or other methods to have a predetermined cross-sectional shape, as described below.

[0043] Next, the molded kneaded product is heat-treated to produce an inorganic oxide support. The heat treatment temperature is, for example, 400 to 1200°C, preferably 450 to 1100°C, and the heat treatment time is, for example, 0.5 to 10 hours, preferably 2 to 5 hours. It is preferable that the heat treatment temperature is equal to or higher than the lower limit from the viewpoint of preventing organic additives from remaining in the inorganic oxide support and from the viewpoint of preventing a decrease in the average pore diameter of the inorganic oxide support. It is preferable that the heat treatment temperature is equal to or lower than the upper limit from the viewpoint of preventing a decrease in the specific surface area of ​​the support. Prior to the heat treatment, the shaped kneaded product may be dried by heating at, for example, 70 to 150°C, preferably 90 to 130°C.

[0044] (active metal component) The inorganic oxide support carries an active metal component. The inorganic oxide carrier is impregnated with an impregnation solution containing a raw material of an active metal component, an acid, and water, to support the raw material of the metal component on the inorganic oxide carrier. The metal component usually contains molybdenum, and also contains nickel and / or cobalt.

[0045] The molybdenum content in the first layer catalyst is preferably 1 to 6 mass%, more preferably 1 to 5 mass%, calculated as oxide (MoO3), and the molybdenum content in the second layer catalyst is preferably 1 to 9 mass%, more preferably 2 to 8 mass%. The total contents of nickel and cobalt in both the first layer catalyst and the second layer catalyst are preferably 0.1 to 5.0 mass%, more preferably 0.2 to 4.0 mass%, calculated as oxide (NiO, CoO).

[0046] Examples of raw materials for the active metal component include molybdenum trioxide, ammonium molybdate, cobalt nitrate, cobalt carbonate, nickel nitrate, and nickel carbonate. The amount of each metal component in the raw material is set so that the amount of molybdenum and the amount of nickel and / or cobalt in the produced hydrogenation catalyst are within the above-mentioned ranges. The amount or composition of the raw material metal components is appropriately selected depending on the type of feedstock oil to be hydrotreated or the use of the product oil.

[0047] When preparing the impregnation liquid, it is preferable to use an inorganic or organic acid to adjust the pH of the impregnation liquid to 4 or less and dissolve the raw material of the metal component. Examples of inorganic acids include phosphoric acids and nitric acid, and examples of phosphoric acids that can be used include phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, trimetaphosphoric acid, pyrophosphoric acid, and tripolyphosphoric acid. Examples of organic acids that can be used include citric acid, malic acid, tartaric acid, acetic acid, ethylenediaminetetraacetic acid (EDTA), and diethylenetriaminepentaacetic acid (DTPA), with citric acid and malic acid being particularly suitable.

[0048] The first layer catalyst and the second layer catalyst are produced by calcining the inorganic oxide catalyst carrying the raw materials of the metal components. The calcination temperature is, for example, 400 to 800° C., preferably 400 to 750° C., and more preferably 450 to 700° C., and the calcination time is, for example, 0.5 to 10 hours, and preferably 1 to 8 hours.

[0049] (Cross-sectional shape of first layer catalyst) 1 is a diagram showing one embodiment of a cross section perpendicular to the axial direction of a cylindrical first-layer catalyst. The first-layer catalyst has a predetermined length with the major axis being perpendicular to the plane of the paper in FIG.

[0050] 1, the cross section of the first layer catalyst 2 has four first concave edges 4 and four first convex edges 6 alternately connected to form a closed region, with a hollow portion 8 at the center of the cross section. Therefore, when viewed from the outside, the first layer catalyst 2 has a hollow structure in which the hollow portion 8 penetrates in the major axis direction and has a gear-shaped outer circumferential surface with alternating convex and concave portions.

[0051] The first concave edge 4 and the first convex edge 6 may be directly connected, or may be connected via a first connecting edge (not shown) that connects them. The total length of the first connecting edge may be, for example, 20% or less, 10% or less, or 5% or less of the perimeter of the cross-section.

[0052] The first layer catalyst 2 has grooves (the first concave edge 4 in the cross-section) on its surface. Since the first layer catalyst 2 mainly has its major axis direction horizontal during filling, the grooves also face the horizontal direction, enhancing the liquid diffusivity of the feedstock oil in the horizontal direction. Furthermore, due to the grooves and hollow structure of the catalyst, the porosity of the first layer is increased, and it is considered that the descaling ability and liquid redispersion ability are enhanced, that is, the ability to suppress the deposition of scale and the generation of uneven flow is enhanced.

[0053] Here, when the cross-section of the first layer catalyst 2 is defined such that the radius of curvature of the first concave edge 4 is R1 and its arc length is L1, and the radius of curvature of the first convex edge 6 is R2 and its arc length is L2, it preferably satisfies the conditions of 1.5 < R1 / R2 < 10 and 0.5 < L1 / L2 < 3.0. Note that Fig. 1 illustrates the case where R1 / R2 = 5 and L1 / L2 = 1.

[0054] More preferably, 2 < R1 / R2 < 10, and even more preferably, 3 < R1 / R2 < 8. Also, more preferably, 0.6 < L1 / L2 < 2.5, and even more preferably, 0.7 < L1 / L2 < 2.0.

[0055] As described above, by imposing predetermined conditions on the radius of curvature and arc length of the first concave edge 4 and the first convex edge 6 that constitute the cross-section of the first layer catalyst 2, when a guard catalyst layer is provided in a hydrotreating apparatus and hydrocarbon oil is flowed through the guard catalyst layer, the descaling ability to moderately capture scale at the grooves (concave surfaces) on the surface of the outer edge portion of the first layer catalyst 2 can be enhanced, and the fluidity (liquid diffusivity) of the hydrocarbon oil can be improved. That is, the ability to suppress the deposition of scale and the generation of uneven flow can be enhanced.

[0056] In contrast, Fig. 2(a) is a diagram showing a cross-section of the first layer catalyst 2 when the value of R1 / R2 is 0.2. When R1 / R2 > 1.5, the first concave edge 4, which is the constricted portion of the first layer catalyst 2, does not become too deep, and the first convex edge 6, which is the lobe portion, is excellent in resistance to mechanical shock.

[0057] Further, Fig. 2(b) is a diagram showing a cross-section of the first layer catalyst 2 when the value of L1 / L2 is kept at 5 as shown in Fig. 1 and the value of L1 / L2 is 0.5 or less. When L1 / L2 > 0.5, the first concave edge 4 of the first layer catalyst 2 becomes long and deep, so that the fluidity of the hydrocarbon oil and the scale capturing ability are improved.

[0058] Further, Fig. 2(c) is a diagram showing a cross-section of the first layer catalyst 2 when the value of R1 / R2 is 2 and the value of L1 / L2 is 3.0 or more. When L1 / L2 < 3.0, the first concave edge 4, which is the constricted portion of the guard catalyst, does not become too large and deep, and the first convex edge 6, which is the lobe portion, is excellent in resistance to mechanical shock.

[0059] Further, the hollow portion 8 has a circular shape. When the radius of the hollow portion 8 is defined as R3 and the radius of the circumscribed circle 12 circumscribing the first layer catalyst is defined as R4, preferably the condition 0.2 < R3 / R4 < 0.8 is satisfied.

[0060] The hollow portion 8 may have a polygonal shape as shown in Fig. 3. In this case, when the radius of the circumscribed circle 10 of the polygon of the hollow portion 8' is defined as the radius R3 of the hollow portion 8' and the radius of the circumscribed circle 12 circumscribing the first layer catalyst 2 is defined as R4, preferably the condition 0.2 < R3 / R4 < 0.8, more preferably 0.3 < R3 / R4 < 0.7 is satisfied. When R3 / R4 > 0.2, the diameters of the hollow portions 8 and 8' are thick, and the fluidity of the hydrocarbon oil and the scale capturing ability can be increased. Also, when R3 / R4 < 0.8, the first layer catalyst is thick in the radial direction of the cross-section and excellent in mechanical strength. When the polygonal hollow portion 8' is adopted, the number of corners of the hollow portion 8' is preferably four or more.

[0061] In addition, the first-layer catalysts 2 and 2' shown in FIGS. 1 and 3 satisfy the condition of 0.2 < R3 / R4 < 0.8. Thereby, while maintaining the mechanical strength of the guard catalyst, the fluidity of the hydrocarbon oil and the scale capture ability can be increased.

[0062] In the cross-section, the diameter of the circumscribed circle 12 circumscribing the first-layer catalyst 2 is preferably 2 to 15 mm, and the length of the first-layer catalyst 2 in the major axis direction is preferably 7 to 30 mm. Also, the first-layer catalyst 2 does not necessarily have to form a region with a predetermined quantitative condition in which four first concave edges 4 and four first convex edges 6 are alternately connected and closed as described above.

[0063] For example, the number of the first concave edges 4 and the first convex edges 6 is not necessarily limited to four, and three to fourteen first concave edges 4 and first convex edges 6 may be alternately connected and closed. In addition, it is more preferable that the number of the first concave edges 4 and the first convex edges 6 is three to eight.

[0064] And the first concave edge 4 and the first convex edge 6 do not necessarily have to have a predetermined radius of curvature. The concave edge 4 has a curve concave toward the center side of the cross-section of the first-layer catalyst 2, and the first convex edge 6 may be composed of a curve protruding to the side opposite to the center of the cross-section of the first-layer catalyst 2.

[0065] Also, the first concave edge 4 and the first convex edge 6 do not necessarily have to be composed of curves. The first concave edge 4 may have a "<"-shaped straight line refracted toward the center side of the cross-section of the first-layer catalyst 2, and the first convex edge 6 may be composed of a "<"-shaped straight line refracted to the side opposite to the center of the cross-section of the first-layer catalyst 2.

[0066] (Cross-sectional shape of the second-layer catalyst) In the cross-section perpendicular to the major axis direction of the columnar second-layer catalyst (not shown), a plurality of second concave edges composed of a curve concave toward the center side of the cross-section of the second-layer catalyst or a straight line refracted toward the center side of the cross-section of the second-layer catalyst, and the same number of second convex edges composed of a curve protruding to the side opposite to the center of the cross-section of the second-layer catalyst or a straight line refracted to the side opposite to the center of the cross-section of the second-layer catalyst are alternately connected and closed to form a region.

[0067] The second concave edge and the second convex edge may be directly connected to each other, or may be connected to each other via a second connecting edge (not shown) that connects them. The total length of the second connecting edge may be, for example, 20% or less, 10% or less, or 5% or less of the perimeter of the cross section. Specific examples of the cross-sectional shape include a trilobe type and a quadrlobe type, and these may be conventional and common.

[0068] The second layer catalyst has a groove (a second concave edge in cross section) on its surface. Since the major axis of the second layer catalyst 2 is mainly oriented horizontally when packed, the groove also faces horizontally, which increases the horizontal liquid diffusion of the feed oil, thereby enhancing the drift suppression ability.

[0069] The center of the cross section of the second layer catalyst preferably does not have a hollow portion 8. A second layer catalyst that does not have a hollow portion 8 has excellent mechanical strength. The diameter of the circumscribing circle circumscribing the second layer catalyst in the cross section is preferably 1.5 to 10 mm, and the length of the second layer catalyst in the major axis direction is preferably 3 to 15 mm. The diameter of the circumscribing circle of the second layer catalyst is preferably smaller than the diameter of the circumscribing circle of the first layer catalyst.

[0070] (Catalyst properties) The first layer catalyst 2 preferably has a pore volume (PV) of 0.5 to 1.4 ml / g as measured by a water pore filling method. If the pore distribution of the first layer catalyst is 0.5 ml / g or more, the first layer catalyst itself can also have the ability to capture metals to be removed, such as Ni and V, contained in the feed oil. If the pore volume is 1.4 ml / g or less, the first layer catalyst has good crushing strength.

[0071] The second layer catalyst has a pore volume (PV) of 0.8 to 1.4 ml / g as measured by a water pore filling method. The second layer catalyst has a bimodal pore distribution. Specifically, the second layer catalyst has two maxima in the pore size range of 5 to 10,000 nm in the pore size distribution measured by mercury intrusion porosimetry, preferably has one maximum in the pore size range of 5 to 100 nm and one maximum in the pore size range of more than 100 nm to 10,000 nm, more preferably has one maximum in the pore size range of 10 to 80 nm and one maximum in the pore size range of 200 to 5,000 nm.

[0072] The second layer catalyst has mesopores that allow it to capture metal components such as Ni and V dissolved in the feed oil, and it has macropores that allow the oil to diffuse efficiently. The ratio (PVma / PVme) of the pore volume (PVma) of pores with diameters in the range of 100 to 10,000 nm to the pore volume (PVme) of pores with diameters in the range of 5 to 100 nm is preferably 0.1 to 0.5. The shape of the pore distribution can be made bimodal, for example, by preparing the support according to the method described in Japanese Patent No. 5,922,372.

[0073] The second layer catalyst has a high pore volume and a bimodal pore distribution, i.e., it has macropores through which the feed oil can easily diffuse, so that the feed oil easily penetrates into the catalyst, and the oil that penetrates diffuses into the catalyst and then seeps out below the catalyst, so it has an oil diffusion ability and is therefore considered to exhibit drift suppression capabilities. In addition, the second layer catalyst has mesopores, so it is considered to capture metal components such as Ni and V dissolved in the feed oil.

[0074] (Guard catalyst layer) The guard catalyst layer according to the present invention is formed by laminating a first layer including a first layer catalyst 2 and a second layer including a second layer catalyst layer, and when used in the hydrotreating of hydrocarbon oils, particularly heavy oils, it exhibits high drift suppression capabilities and scale capture capabilities.

[0075] The proportion of the first catalyst layer in the guard catalyst layer is preferably 10 volume % to 90 volume %, more preferably 20 volume % to 80 volume %. When the proportion of the first catalyst layer is in this range, the first catalyst layer can fully exhibit its scale capturing ability.

[0076] The proportion of the second catalyst layer is preferably 10% by volume to 90% by volume, more preferably 20% by volume to 80% by volume of the guard catalyst layer, because the second catalyst layer can fully exert its ability to suppress drift, in particular.

[0077] In a hydrotreating apparatus for hydrocarbon oil, the guard catalyst layer according to the present invention is provided in the upstream part of the flow path of the feed oil (so that the first layer is on the upstream side and the second layer is on the downstream side), and preferably a hydrotreating catalyst layer filled with a hydrotreating catalyst is provided in the downstream part, so that a hydrotreating reaction can be carried out. There is no limitation on the feed oil to be treated with the catalyst according to the present invention, and kerosene, light oil, vacuum gas oil (VGO), etc. can be treated, but it is particularly suitable for treating heavy oil containing a large amount of scale. Heavy oil is mainly composed of residues from distillation, and examples of high-density petroleum fractions include atmospheric distillation residue (AR), vacuum distillation residue (VR), catalytic cracking residue, visbreaking oil, and bitumen.

[0078] These heavy oils usually contain 1% by mass or more of asphaltene, and asphaltene extracted from these heavy oils can also be used as feedstock oil. In the present invention, these may be used alone or in combination as feedstock oil. In addition, coker oil, synthetic crude oil, naphtha cut crude oil, heavy diesel oil, vacuum diesel oil, LCO, GTL (Gas To Liquid) oil, wax, etc. can be mixed with atmospheric distillation residue oil, etc. to produce heavy oil and hydrotreat.

[0079] The raw material heavy oil has a density of 0.9 to 1.05 g / cm 3Preferably, the distillation properties are such that the sulfur content is 1 to 6 mass %, the nitrogen content is more than 2000 mass ppm and not more than 10000 mass ppm, and components having a boiling point of 360° C. or higher account for 80 mass % or more.

[0080] Hydrotreatment using the guard catalyst layer of the present invention is carried out, for example, by stacking the catalyst in a fixed bed reactor so as to form, in the flow direction, a guard section, a demetalization section, a transition section and a desulfurization section, and passing heavy oil through the reactor under high temperature and high pressure conditions in a hydrogen atmosphere.

[0081] The resulting treated oil is subjected to catalytic cracking in a fluid catalytic cracker as necessary. The catalytic cracking in the fluid catalytic cracker is not particularly limited and may be performed by a known method and conditions. For example, an amorphous catalyst such as silica-alumina or silica-magnesia or a zeolite catalyst such as faujasite-type crystalline aluminosilicate may be used, and the reaction temperature may be appropriately selected from the range of about 450 to 650°C, preferably 480 to 580°C, the regeneration temperature from about 550 to 760°C, and the reaction pressure from about 0.1 to 5 MPa, preferably 0.2 to 2 MPa. The product oil subjected to catalytic cracking in the fluid catalytic cracker, which is the final step, may be used as a fuel or a raw material for petrochemical products. EXAMPLES

[0082] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0083] <Method for measuring pore size distribution> Approximately 3 g of the measurement sample was collected in a magnetic crucible, heated at 500°C for 1 hour, then cooled to room temperature in a desiccator to obtain a measurement sample. The pore distribution was then measured using a mercury intrusion method (Quantachrome Poremaster GT-60) under the following conditions: mercury contact angle: 150°, surface tension: 480 dyn / cm for the carrier, and mercury contact angle: 130°, surface tension: 470 dyn / cm for the catalyst. The average pore diameter was taken as the pore diameter equivalent to 50% of the pore volume. Pores with one maximum value in the range of 5 nm to 10,000 nm were considered to be unimodal, and those with two maximum values ​​were considered to be bimodal.

[0084] <Method for measuring the pore volume of the carrier> Approximately 30 g of the measurement sample was placed in a porcelain crucible and heat-treated at 500°C for 1 hour. The sample was then placed in a desiccator and cooled to room temperature to obtain a measurement sample. The pore volume was then measured by the water pore filling method.

[0085] <Preparation of Carrier> [Carrier Preparation Example 1] (Preparation of Support (1-A)) 35.2 kg of pure water was charged into a tank equipped with a circulation line having two chemical addition ports, and 13.0 kg of an aqueous aluminum sulfate solution (concentration of 7% by mass as Al2O3), which is an acidic aluminum salt solution, was added while stirring, and the solution was heated to 60°C and circulated. The pH of the obtained diluted aluminum sulfate aqueous solution was 2.3. Next, 9.5 kg of an aqueous sodium aluminate solution (concentration of 22% by mass as Al2O3), which is an aqueous basic aluminum salt solution, was added to the above-mentioned diluted aluminum sulfate aqueous solution over 180 minutes while stirring, circulating, and maintaining at 60°C, to obtain alumina hydrate. The pH of the aqueous solution after addition was 9.5. The alumina hydrate was washed with pure water at 60°C to remove impurities such as sodium and sulfate. Pure water was added to the washed cake to adjust the Al2O3 concentration to 8% by mass, and then the mixture was aged at 95°C for 3 hours in an aging tank equipped with a reflux condenser, and further dehydrated to obtain a cake-like alumina hydrate.

[0086] The cake-like alumina hydrate thus obtained was concentrated and kneaded in a twin-arm kneader equipped with a steam jacket. The kneaded product obtained was extruded into a columnar shape using a hollow four-lobe die with a hole shape of R1 / R2=5, R3 / R4=0.5, L1 / L2=1 and a diameter (diameter of the circumscribed circle, the same applies below)=6.5 mm in an extrusion molding machine, and cut to a predetermined length (10 mm) to obtain an alumina molded product. The obtained alumina molded product was dried at 110°C for 12 hours and then calcined at 500°C for 3 hours to obtain a carrier (1-A).

[0087] [Carrier Preparation Example 2] (Preparation of Support (1-B)) Carrier (1-B) was obtained in the same manner as in Carrier Preparation Example 1, except that the die was changed to a hollow four-lobe die with hole shapes of R1 / R2=5, R3 / R4=0.1, L1 / L2=1 and diameter=6.5 mm.

[0088] [Carrier Preparation Example 3] (Preparation of Support (1-C)) Carrier (1-C) was obtained in the same manner as in Carrier Preparation Example 1, except that the die was changed to a hollow four-lobe die with hole shapes of R1 / R2=5, R3 / R4=0.5, L1 / L2=0.2 and diameter=6.5 mm.

[0089] [Carrier Preparation Example 4] (Preparation of Support (1-D)) A carrier (1-D) was obtained in the same manner as in Carrier Preparation Example 1, except that the die was changed to a solid four-lobe die with a hole shape of R1 / R2=5, L1 / L2=1 and a diameter of 6.5 mm.

[0090] [Carrier Preparation Example 5] (Preparation of Support (1-E)) A carrier (1-E) was obtained in the same manner as in Carrier Preparation Example 1, except that the die was changed to a solid circular die having a hole with a diameter of 6.5 mm.

[0091] [Carrier Preparation Example 6] (Preparation of Support (2-A)) A carrier (2-A) was obtained in the same manner as in Carrier Preparation Example 1, except that the die was changed to a general solid four-lobe die having a hole shape of 1.7 mm in diameter.

[0092] [Carrier Preparation Example 7] (Preparation of Support (2-B)) A carrier (2-B) was obtained in the same manner as in Carrier Preparation Example 6, except that the die was changed to a general solid circular die having a hole shape of 1.7 mm in diameter.

[0093] [Carrier Preparation Example 8] (Preparation of Support (2-C)) A carrier (2-C) was obtained in the same manner as in Carrier Preparation Example 6, except that 200 g of 60% nitric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to the alumina hydrate when kneading the alumina hydrate with a twin-arm kneader.

[0094] <Preparation of impregnation solution> [Impregnation liquid preparation example 1] (Preparation of impregnation solution (a)) 21.2 g of molybdenum trioxide and 7.7 g of nickel carbonate were suspended in 400 ml of ion-exchanged water, and this suspension was heated at 90°C for 5 hours using an appropriate reflux device so as not to reduce the volume of the liquid. Then, 8.6 g of phosphoric acid and 6.4 g of citric acid were added and dissolved to prepare an impregnation solution (a).

[0095] [Impregnation liquid preparation example 2] (Preparation of impregnation solution (b)) 38.6 g of molybdenum trioxide and 14.1 g of nickel carbonate were suspended in 350 ml of ion-exchanged water, and this suspension was heated at 90°C for 5 hours using an appropriate reflux device so as not to reduce the volume of the liquid. Then, 9.0 g of phosphoric acid and 11.6 g of citric acid were added and dissolved to prepare an impregnation solution (b).

[0096] [Catalyst Preparation Example 1] <Preparation of first layer catalyst (1-a)> 500 g of the carrier (1-A) obtained in Carrier Preparation Example 1 was diluted with pure water to be equal to the pore volume of 500 g of the carrier (1-A) and the impregnation liquid (a) obtained in Impregnation Liquid Preparation Example 1 was sprayed and impregnated therein. The carrier thus obtained was dried at 250°C and further calcined in an electric furnace at 550°C for 1 hour to obtain a first layer catalyst (1-a).

[0097] [Catalyst Preparation Examples 2-5] <Preparation of first layer catalysts (1-a) to (1-e)> First layer catalysts (1-a) to (1-e) were prepared in the same manner as in Catalyst Preparation Example 1, except that the types of carrier and impregnation solution were changed as shown in Table 1.

[0098] [Catalyst Preparation Example 6] <Preparation of second layer catalyst (2-a)> 500 g of the carrier (2-A) obtained in Carrier Preparation Example 6 was diluted with pure water to be equal to the pore volume of 500 g of the carrier (2-A), and the impregnation liquid (b) obtained in Impregnation Liquid Preparation Example 2 was sprayed and impregnated therein. The carrier thus obtained was dried at 250°C and further calcined in an electric furnace at 550°C for 1 hour to obtain a second layer catalyst (2-a).

[0099] [Catalyst Preparation Examples 7-8] <Preparation of second layer catalysts (2-a) to (2-b)> Second layer catalysts (2-i) to (2-iii) were prepared in the same manner as in Catalyst Preparation Example 6, except that the types of carrier and impregnation solution were changed as shown in Table 1.

[0100] [Example 1] <Formation of guard catalyst layer> An acrylic cylinder with a diameter of 30 cm and a length of 0.8 m was fixed so that the long axis direction was vertical. A liquid receiving part with a stainless steel wire mesh on the top surface was attached directly below the acrylic cylinder so that there was no gap between the acrylic cylinder and the liquid receiving part. The liquid receiving part was divided with acrylic plates so that the cross section perpendicular to the length direction of the acrylic cylinder was divided into 13 equal sectors.

[0101] The acrylic cylinder was filled with the second layer catalyst (2-A) on top of the liquid receiver until it reached a height of 30 cm, and the surface was smoothed flat. The first layer catalyst (1-A) was then filled on top of the layer of the second layer catalyst (2-A) in the acrylic cylinder until it reached a height of 30 cm, and the surface was smoothed flat to form a guard catalyst layer. The total height of the first layer catalyst (1-A) layer and the second layer catalyst (2-A) layer was 60 cm, and 20 cm was left empty from the top of the first layer catalyst (1-A) to the top of the acrylic cylinder. An acrylic porous plate with a diameter of 30 cm and 75 uniformly sized holes with a diameter of 0.5 cm was placed on the upper end of the acrylic cylinder.

[0102] [Examples 2 to 3, Comparative Examples 1 to 4] A guard layer was formed inside the acrylic cylinder and an acrylic perforated plate was placed on the upper end of the acrylic cylinder in the same manner as in Example 1, except that the combination of the first layer catalyst and the second layer catalyst was changed as shown in Table 1.

[0103] <Evaluation of guard catalyst layer> (Evaluation of the scale capture ability of catalysts) 100 g of powdered iron oxide (III) (Merck, <5 μm grade) that had been dried at 400 °C for 1 hour in advance was suspended in 9 L of commercially available kerosene, which was then passed through an acrylic cylinder from above a porous acrylic plate at a rate of 5 L / min for 2 minutes. The kerosene that had passed through the guard catalyst layer was collected in the liquid receiver, and kerosene was collected from each of the 13 divided liquid receivers, and the iron oxide powder and kerosene were separated by vacuum filtration. The amount of scale that was not captured by the guard catalyst layer was quantified by measuring the weight of the collected iron oxide powder after drying at 400 °C for 1 hour. The scale capture ability of the guard catalyst layer was calculated using the following formula. Scale capture index = (100 - total weight of iron oxide recovered from the liquid receiver (g)) / 100 That is, a larger scale trapping ability index indicates a larger amount of scale trapped in the guard catalyst layer.

[0104] (Evaluation of catalyst drift suppression ability) Commercially available kerosene was allowed to flow through the acrylic cylinder from above the acrylic perforated plate at a rate of 5 L / min for 2 minutes. The kerosene that had passed through the guard catalyst layer was collected in the liquid receiver, and the weight of the kerosene collected in each of the 13 divided liquid receivers was measured, and the standard deviation was calculated. The standard deviation in Example 1 was taken as 100, and the relative value was calculated and compared to determine the drift suppression ability of the guard catalyst layer. In other words, the smaller the value, the less drift occurred.

[0105] [Table 1] [Explanation of symbols]

[0106] 2, 2´ First layer catalyst 4 First concave edge 6 First convex edge 8, 8´ Hollow part 10 Polygon circumcircle 12 Circumscribed Circle

Claims

1. A porous carbon nanotube composite material comprising a first layer including a first-layer catalyst that is columnar and has a hollow portion penetrating in the longitudinal direction, and a second layer including a second-layer catalyst that is columnar and has a bimodal pore distribution, wherein the first layer is laminated with the second layer. the first catalyst comprises an inorganic oxide support on which a metal component is supported, a periphery of a cross section of the first catalyst perpendicular to the longitudinal direction includes a first concave edge recessed toward the center of the cross section and a first convex edge protruding to the side opposite to the center of the cross section, the second layer catalyst includes an inorganic oxide support on which a metal component is supported, the periphery of a cross section of the second layer catalyst perpendicular to the longitudinal direction includes a second concave edge recessed toward the center of the cross section and a second convex edge protruding to the side opposite to the center of the cross section, The second layer catalyst has a pore volume of 0.8 to 1.4 ml / g as measured by a water pore filling method.

2. A guard catalyst layer as described in claim 1, characterized in that the second layer catalyst is solid.

3. The first concave edge is a curve concave toward the center of the cross section, 2. The guard catalyst according to claim 1, wherein the first convex edge is a curved line projecting in a direction opposite to the center of the cross section.

4. A hydrocarbon oil hydrotreating treatment apparatus comprising the guard catalyst layer according to claim 1.

5. A method for hydrotreating a hydrocarbon oil, comprising a hydrotreating step of contacting the hydrocarbon oil with the guard catalyst layer according to claim 1.

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