Hydrotreating catalyst for heavy hydrocarbon oil, method for producing the same, and method for hydrotreating heavy hydrocarbon oil

Abstract

Provided is a hydrotreating catalyst for a heavy hydrocarbon oil, the catalyst including an inorganic oxide carrier including alumina as a main component and a metal component supported on the inorganic oxide carrier, the catalyst having a specific surface area within a predetermined range, a reduction peak temperature that is lower than 450° C. in temperature-programmed reduction measurement of the catalyst and that is higher than or equal to a predetermined temperature, and an amount of nitrogen monoxide adsorbed on the sulfided catalyst within a predetermined range.

Claims

1. A hydrotreating catalyst for a heavy hydrocarbon oil, comprising: an inorganic oxide carrier comprising alumina as a main component and an additive oxide component; and a metal component supported on the inorganic oxide carrier, the metal component containing molybdenum and containing nickel and/or cobalt, the catalyst having: a molybdenum content of 5% to 16% by mass on an oxide basis, and a total nickel and cobalt content of 1% to 6% by mass on an oxide basis, a specific surface area measured by a nitrogen adsorption method of 150 to 320 m.sup.2/g, a value of a reduction peak temperature (° C.) that is lower than 450° C. in temperature-programmed reduction measurement of the catalyst and that is higher than or equal to a value A (° C.) given by an equation below: the value A (° C.)=1.0×(the molybdenum content (% by mass) of the catalyst in terms of MoO.sub.3)+25×(the ratio of the cobalt content (% by mass) of the catalyst in terms of CoO to the sum (% by mass) of the nickel content of the catalyst in terms of NiO and the cobalt content of the catalyst in terms of CoO)+339, and after sulfurization treatment of the catalyst, an amount of nitrogen monoxide adsorbed of 4.0 mL/g or more when a mole ratio (Ni/(Ni+Co)) of the amount of nickel to the total amount of nickel and cobalt in the catalyst is 0.5 or more, and the amount of nitrogen monoxide adsorbed of 5.0 mL/g or more when the mole ratio is less than 0.5, wherein the inorganic oxide carrier contains 1% to 30% by mass of the additive oxide component, and the additive oxide component contains at least an oxide of any one of additive element(s) (a) to (c) below: (a) magnesium or boron, (b) a combination of silicon and at least one element(s) M selected from the group consisting of titanium, zirconium, boron, magnesium, and phosphorus, the ratio of silicon to the element(s) M being 0.4 to 3.5 in terms of (mass of silica)/(mass of the oxide of the element(s) M), and (c) a combination of titanium and phosphorus or a combination of zirconium and phosphorus.

2. The hydrotreating catalyst for a heavy hydrocarbon oil according to claim 1, wherein the inorganic oxide carrier satisfies that: the average pore diameter (PD) measured by a mercury intrusion method is 9.0 to 15.0 nm, the sum of pore volumes of pores having a pore diameter in a range of ±2 nm of the average pore diameter is 50% or more of the total pore volume, the sum of pore volumes of pores having a pore diameter in a range of 20 nm or more is 10% or less of the total pore volume, and the pore volume (PV) measured by a pore-filling method with water is 0.5 to 1.1 mL/g.

3. A method for producing the hydrotreating catalyst for a heavy hydrocarbon oil according to claim 1, the method comprising the steps of: (1) preparing a slurry containing a precursor of the inorganic oxide carrier and having a pH of 7 to 10 and then shaping the precursor; (2) calcining the shaped precursor at 400° C. to 800° C. to provide the inorganic oxide carrier; (3) preparing an impregnating solution comprising a raw material for the metal component, an acid, and water, and impregnating the inorganic oxide carrier with the impregnating solution to support the raw material for the metal component on the inorganic oxide carrier; and (4) calcining the inorganic oxide carrier supporting the raw material for the metal component at 400° C. to 800° C. to provide the hydrotreating catalyst, wherein the step (1) includes: an operation (1-1) of adding an aqueous solution (b) containing a basic aluminum salt to an aqueous solution (a) containing an acidic aluminum salt and having a pH of 2 to 5 to prepare a slurry of the precursor containing alumina hydrate; and an operation (1-2) of mixing the alumina hydrate and/or a raw material for the alumina hydrate with a raw material for the additive oxide component.

4. The method for producing the hydrotreating catalyst for a heavy hydrocarbon oil according to claim 3, wherein in the operation (1-2), (i) an aqueous solution of the acidic aluminum salt is mixed with the raw material for the additive oxide component to prepare the aqueous solution (a), (ii) an aqueous solution of the basic aluminum salt is mixed with the raw material for the additive oxide component to prepare the aqueous solution (b), (iii) the aqueous solution (a), the aqueous solution (b), and the raw material for the additive oxide component are mixed together to prepare the slurry containing the precursor, or (iv) the slurry containing the alumina hydrate is mixed with the raw material for the additive oxide component to prepare the slurry containing the precursor.

5. A method for hydrotreating a heavy hydrocarbon oil, comprising a step of: hydrotreating the heavy hydrocarbon oil in the presence of the hydrotreating catalyst according to claim 1.

6. The method for hydrotreating a heavy hydrocarbon oil according to claim 5, wherein the heavy hydrocarbon oil has a density of 0.90 to 1.05 g/cm.sup.3 and a sulfur content of 1% to 6% by mass and contains 80% or more by mass of a component having a boiling point of 360° C. or higher.

7. The method for hydrotreating a heavy hydrocarbon oil according to claim 5, wherein the step of hydrotreating the heavy hydrocarbon oil is performed at a hydrogen partial pressure of 5.0 to 20 MPa, a reaction temperature of 350° C. to 420° C., and a liquid hourly space velocity of 0.1 to 0.5 hr.sup.−1.

8. The method for hydrotreating a heavy hydrocarbon oil according to claim 5, wherein the method is performed as pretreatment of fluidized-bed catalytic cracking of the heavy hydrocarbon oil.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIGURE illustrates the measurement results of the reduction temperature of the metal component of catalyst (7) in Example 1 by a temperature-programmed reduction method.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(2) Embodiments of the present invention will be described below.

(3) Embodiments of the present invention provide a hydrotreating catalyst for a heavy oil, a method for producing the hydrotreating catalyst, and a method for hydrotreating a heavy oil. The catalyst produced in accordance with an embodiment of the present invention (hereinafter, also referred to as a “present catalyst”) can be placed and used in any area of a demetallization section, a desulfurization section, and a transition section provided therebetween in a hydrotreater for a heavy oil. The catalyst can be suitably used particularly in the desulfurization section.

(4) In the demetallization section of the hydrotreater for a heavy oil, demetallization with a demetallization catalyst is mainly performed in the presence of hydrogen gas to remove metal components in a feedstock oil. In the desulfurization section, a hydrogenation reaction is mainly performed with a desulfurization catalyst in the presence of hydrogen gas to remove sulfur components, nitrogen components, and residual carbon components.

(5) [Hydrotreating Catalyst]

(6) The hydrotreating catalyst according to an embodiment of the present invention is a catalyst used for the hydrotreatment of a heavy hydrocarbon oil, includes an inorganic oxide carrier composed of alumina as a main component and a metal component supported on the inorganic oxide carrier, has a specific surface area in a predetermined range, has a reduction peak temperature that is lower than 450° C. in a temperature-programmed reduction measurement of the catalyst and that is higher than or equal to a predetermined temperature, and has an amount of nitrogen monoxide adsorbed after the sulfurization treatment of the catalyst in a predetermined range.

(7) <Inorganic Oxide Carrier>

(8) The inorganic oxide carrier used in the catalyst according to an embodiment of the present invention is a carrier that is mainly composed of alumina and that contains an additive oxide component.

(9) The inorganic oxide carrier preferably contains 70% to 99% by mass, more preferably 75% to 98% by mass, even more preferably 80% to 97% by mass aluminum on an oxide (Al.sub.2O.sub.3) basis.

(10) The inorganic oxide carrier, which is mainly composed of alumina within the above composition range, is suitable as a carrier for the hydrotreating catalyst because the carrier has a high specific surface area, a pore diameter suitable for the treatment of a heavy oil, high crushing strength, high abrasion resistance, and high productivity, such as good suitability for extrusion molding.

(11) The additive oxide component is an oxide of an additive element(s) other than aluminum. A preferred example thereof is an oxide of one of the following additive element(s) (a), (b), and (c):

(12) (a) magnesium or boron,

(13) (b) a combination of silicon and at least one element(s) M selected from the group consisting of titanium, zirconium, boron, magnesium, and phosphorus, the ratio of silicon to the element(s) M being 0.4 to 3.5 in terms of (mass of silica)/(mass of the oxide of the element(s) M), and
(c) a combination of titanium and phosphorus or a combination of zirconium and phosphorus.

(14) The inorganic oxide carrier preferably contains 1% to 30% by mass, more preferably 2% to 25% by mass, even more preferably 3% to 20% by mass of the above-mentioned additive element(s) on an oxide basis.

(15) The description that the inorganic oxide carrier contains alumina and the additive oxide component usually indicates that the inorganic oxide contains a composite oxide of aluminum and the additive element(s).

(16) The inorganic oxide carrier preferably satisfies requirements (i) and (ii) below. More preferably, the inorganic oxide carrier further satisfies requirement (iii) below.

(17) Requirement (i): The average pore diameter (PD) measured by a mercury intrusion method is in the range of 9.0 to 15.0 nm, preferably 9.0 to 14.0 nm.

(18) Requirement (ii): The sum of pore volumes of pores having a pore diameter in a range of ±2 nm of the average pore diameter is 50% or more, preferably 55% or more of the total pore volume. Requirement (iii): The sum of pore volumes of pores having a pore diameter in a range of 20 nm or more is 10% or less of the total pore volume.

(19) In addition, the inorganic oxide carrier preferably satisfies requirement (iv) below.

(20) Requirement (iv): The pore volume (PV) measured by a pore-filling method with water is 0.5 to 1.1 mL/g, preferably 0.6 to 1.0 mL/g.

(21) The details of measurement methods for the physical properties are described in the EXAMPLES section below.

(22) The catalyst containing the inorganic oxide carrier having the components and the composition is considered to have superior catalytic performance because it has both high diffusibility of a heavy oil having a relatively large molecular size and a high specific surface area, which is important to maintain the dispersion of a metal component in a solid catalyst.

(23) <Metal Component>

(24) A catalyst according to an embodiment of the present invention includes a metal component supported on the inorganic oxide carrier. The metal component contains molybdenum and contains nickel and/or cobalt.

(25) The catalyst according to an embodiment of the present invention has a molybdenum content of 5% to 16% by mass, preferably 6% to 15% by mass in terms of oxide (MoO.sub.3).

(26) The catalyst according to an embodiment of the present invention has a total nickel and cobalt content of 1.0% to 6.0% by mass, preferably 1.5% to 5.0% by mass in terms of oxides (NiO and CoO).

(27) <Specific Surface Area>

(28) The catalyst according to an embodiment of the present invention has a specific surface area of 150 to 320 m.sup.2/g as measured by a nitrogen adsorption method (details of the measurement method are described in the Examples section below).

(29) A specific surface area of less than 150 m.sup.2/g may result in insufficient dispersion of the metal component on the inorganic oxide carrier and the formation of aggregates of the metal component, which is not preferred. A specific surface area of the catalyst of more than 320 m.sup.2/g results in a smaller pore diameter, which is not preferred in a reaction using a heavy oil having a large molecular size as a feedstock oil because the diffusibility of molecules of the heavy oil is deteriorated.

(30) <Reduction Peak Temperature>

(31) The present inventors have attempted to develop a novel hydrotreating catalyst for a heavy oil on the basis of temperature-programmed reduction measurement of the catalyst and have found that a catalyst that exhibits a high reduction peak temperature higher than or equal to a certain level has high performance for the hydrotreatment of a heavy oil, compared with catalysts prepared using alumina carriers that have been used by those skilled in the art. The present inventors have further found that the reduction peak temperature correlates with the amount of molybdenum and the ratio of the amount of cobalt to the total amount of nickel and cobalt in the catalyst. These findings have led them to propose the following conditions.

(32) A catalyst in which the value (° C.) of the reduction peak temperature lower than 450° C. in the temperature-programmed reduction measurement of the catalyst according to an embodiment of the present invention is greater than or equal to a value A calculated from equation (1) below, preferably greater than or equal to a value A′ calculated from equation (1′) below, more preferably greater than or equal to a value A″ calculated from equation (1″) below, exhibits high catalytic activity in the hydrotreatment of a heavy oil.
Value A(° C.)=1.0×B+25×C+339  (1)
Value A′(° C.)=1.0×B+25×C+340  (1′)
Value A″(° C.)=1.0×B+25×C+342  (1″)

(33) In equations (1), (1′), and (1″), each B denotes the molybdenum content (% by mass) of the catalyst in terms of MoO.sub.3, and each C denotes the ratio of the cobalt content (% by mass) of the catalyst in terms of CoO to the sum (% by mass) of the nickel content of the catalyst in terms of NiO and the cobalt content of the catalyst in terms of CoO.

(34) The details of the temperature-programmed reduction measurement and the reduction peak temperature are described in the EXAMPLES section below.

(35) The value of the reduction peak temperature of the catalyst greater than or equal to the value A, preferably greater than or equal to the value A′, more preferably greater than or equal to the value A″ indicates that the metal component on the catalyst is less likely to be reduced than catalysts prepared using carriers containing alumina and additive oxide components in the related art. The catalyst according to an embodiment of the present invention with such a reduction peak temperature is suitable as a catalyst for use in the desulfurization of a heavy oil because the structure and the function of the active sites are easily maintained to result in high hydrotreating activity.

(36) Equations (1), (1′), and (1″) were obtained from the findings that a larger amount of MoO.sub.3 in the catalyst results in a higher reduction peak temperature and a higher ratio of the amount of CoO to the total amount of NiO and CoO in the catalyst results in a higher reduction peak temperature, and from the comparative evaluation of the reduction peak temperature and hydrotreating performance of the catalyst according to an embodiment of the present invention and catalysts produced in comparative examples.

(37) An example of a method for producing a catalyst having such a reduction peak temperature is, but not limited to, a method for producing a hydrotreating catalyst described below.

(38) The upper limit of the reduction peak temperature may be, for example, about (value A+10°) C.

(39) <Amount of Nitrogen Monoxide Adsorbed>

(40) The dispersibility of the metal component of the hydrotreating catalyst can be evaluated by measuring the amount of nitrogen monoxide adsorbed on the catalyst that has been subjected to sulfurization treatment. The details of the sulfurization treatment and the measurement method are described in the EXAMPLES section below. The structure of the supported metal component varies in accordance with the mole ratio of nickel to nickel and cobalt. Typically, a higher mole ratio of nickel is considered to lead to a smaller amount of nitrogen monoxide adsorbed.

(41) The amount of nitrogen monoxide adsorbed by the catalyst according to an embodiment of the present invention after sulfurization treatment is 4.0 mL/g or more when the mole ratio (Ni/(Ni+Co)) of the amount of nickel to the total amount of nickel and cobalt in the catalyst is 0.5 or more, and is 5.0 mL/g or more when the aforementioned mole ratio is in the range of less than 0.5. A smaller amount of nitrogen monoxide adsorbed than the above range indicates low dispersibility of the metal component on the catalyst, which is not preferred because the number of active sites is small.

(42) The upper limit of the amount of nitrogen monoxide adsorbed may be, for example, about 9.0 mL/g.

(43) The amount of nitrogen monoxide adsorbed can be increased or decreased, for example, by changing the calcination temperature of the carrier or catalyst, or by adding an optional chelating agent to an impregnating solution containing an active metal in a method for producing a hydrotreating catalyst described below.

(44) The properties and shape of the inorganic oxide carrier are appropriately selected in accordance with various conditions, such as the type and composition of the metal component supported and the application of the catalyst.

(45) To effectively support the above metal component on the carrier in a highly dispersed state and to ensure sufficient catalytic activity, a porous carrier having predetermined pores is usually suitable for use. To control the physical properties, such as mechanical strength and heat resistance, of the carrier or catalyst, an appropriate binder component or additive may be incorporated during the formation of the carrier or catalyst.

(46) The carrier may further contain additives other than the above-mentioned additive oxide components. Examples thereof include minerals, such as aluminosilicates, for example, zeolite, talc, kaolinite, and montmorillonite.

(47) Although a method for preparing a carrier is not limited, a catalyst having, for example, improved hydrocracking activity and crushing strength can be produced by adding the above additives to a carrier precursor obtained by a preparation method described below.

(48) [Method for Producing Hydrotreating Catalyst]

(49) A method for producing a hydrotreating catalyst according to an embodiment of the present invention includes the steps of:

(50) (1) shaping a carrier precursor,

(51) (2) calcining the carrier precursor to provide an inorganic oxide carrier,

(52) (3) supporting a raw material for a metal component on the inorganic oxide carrier, and

(53) (4) calcining the inorganic oxide carrier supporting the raw material for the metal component to provide a hydrotreating catalyst.

(54) (Step (1))

(55) The step (1) is a step of preparing a slurry containing a precursor of the inorganic oxide carrier (hereinafter, also referred to as a “carrier precursor”) and having a pH of 7 to and then shaping the carrier precursor, and includes an operation (1-1) of adding an aqueous solution (b) containing a basic aluminum salt to an aqueous solution (a) containing an acidic aluminum salt to prepare the carrier precursor containing alumina hydrate, and an operation (1-2) of mixing the alumina hydrate and/or its raw materials with raw materials for the additive oxide component (hereinafter, also referred to as “additive oxide component raw materials”).

(56) The operation (1-2) is performed together with or separately from the operation (1-1) in accordance with a specific embodiment.

(57) The carrier precursor includes the alumina hydrate and the additive oxide component raw materials.

(58) <<Operation (1-1)»

(59) In the operation (1-1), the aqueous solution (b) containing the basic aluminum salt is added to the aqueous solution (a) containing the acidic aluminum salt to prepare a slurry of the carrier precursor containing the alumina hydrate.

(60) The aqueous solution (a) containing the acidic aluminum salt is prepared, for example, by adding the acidic aluminum salt to water.

(61) The aqueous solution (a) is prepared in such a manner that the aluminum content is, for example, 0.1% to 2.0% by mass in terms of Al.sub.2O.sub.3 and the pH is 2.0 to 5.0. The aqueous solution is heated to a solution temperature of, for example, 50° C. to 80° C. under stirring.

(62) The acidic aluminum salt is a water-soluble salt. Examples thereof include aluminum sulfate, aluminum chloride, aluminum acetate, and aluminum nitrate.

(63) When the acidic aluminum salt is added to water to prepare the aqueous solution (a), the acidic aluminum salt is preferably added in the form of an aqueous solution containing 0.5% to 20% by mass aluminum in terms of Al.sub.2O.sub.3.

(64) Then, the aqueous solution (b) containing the basic aluminum salt is added to the aqueous solution (a) containing the acidic aluminum salt over a period of, for example, 30 to 200 minutes under stirring in such a manner that the pH is 7 to 10, thereby preparing a slurry of a carrier precursor containing alumina hydrate.

(65) The alumina hydrate is washed with deionized water having a temperature of, for example, 40° C. to 70° C. to remove by-product salts, which are impurities containing, for example, sodium or sulfate radicals, thereby yielding a cake-like alumina hydrate.

(66) Examples of the basic aluminum salt include sodium aluminate and potassium aluminate. The aqueous solution of the basic aluminum salt preferably contains 2% to 30% by mass of aluminum in terms of Al.sub.2O.sub.3.

(67) <<Operation (1-2)»

(68) In the operation (1-2), the alumina hydrate and/or its raw materials are mixed with the additive oxide component raw materials.

(69) Examples of the embodiment of mixing the raw materials for the alumina hydrate and the raw materials for the additive oxide component include:

(70) (i) mixing an aqueous solution of the acidic aluminum salt with the raw materials for the additive oxide component to prepare the aqueous solution (a);

(71) (ii) mixing an aqueous solution of the basic aluminum salt with the raw materials of the additive oxide component to prepare the aqueous solution (b);

(72) (iii) mixing the aqueous solution (a), the aqueous solution (b), and the raw materials for the additive oxide component together to prepare a slurry containing the precursor; and

(73) (iv) mixing the slurry containing the alumina hydrate with the raw materials for the additive oxide component to prepare the slurry containing the precursor.

(74) Examples of the embodiment (i) include adding the above-mentioned additive oxide component raw materials to water when alumina hydrate is prepared; and adding the above-mentioned additive oxide component raw materials to the aqueous solution of the acidic aluminum salt.

(75) Examples of the embodiment (ii) include adding the above-mentioned additive oxide component raw materials to the aqueous solution of the basic aluminum salt.

(76) Examples of the embodiment (iv) include adding the additive oxide component raw materials to the slurry after the preparation of the alumina hydrate; adding the additive oxide component raw materials to the alumina hydrate after washing and desalting; adding the additive oxide component raw materials to the alumina hydrate after high-temperature aging; and adding the additive oxide component raw materials to the alumina hydrate during kneading in a kneader.

(77) The specific embodiment of the operation (1-2) is not limited thereto, and is selected in accordance with various conditions, such as the type and composition of the component added, and the application of the catalyst.

(78) Examples of the additive oxide component raw materials include water-soluble salts, oxide powders, oxide or hydroxide sols, and oxide or hydroxide gels.

(79) Examples of phosphorus-containing additive oxide component raw materials include phosphate compounds, such as ammonium phosphate, potassium phosphate, sodium phosphate, phosphoric acid, and phosphorous acid, which produce phosphate or phosphite ions in water.

(80) Examples of silicon-containing additive oxide component raw materials include sodium silicate, silicon tetrachloride, silica powders, silica sols, and silica gels. Sodium silicate is particularly preferred because it is inexpensive.

(81) Examples of titanium-containing additive oxide component raw materials include titanium tetrachloride, titanium trichloride, titanium sulfate, titanyl sulfate, titanium nitrate, titanium hydroxide gels, metatitanic acid, and titania powders. Titanium sulfate and titanyl sulfate are particularly preferred because they are inexpensive.

(82) Examples of zirconium-containing additive oxide component raw materials include zirconium sulfate, zirconium acetate, zirconium nitrate, zirconium oxychloride, zirconium carbonate, and zirconia powders.

(83) Examples of boron-containing additive oxide component raw materials include boric acid, ammonium borate, sodium borate, and aluminum borate.

(84) Examples of magnesium-containing additive oxide component raw materials include magnesium oxide, magnesium hydroxide, and magnesium sulfate.

(85) <Additives>

(86) If necessary, at least one organic additive selected from organic acids and sugars may be added to the resulting slurry of the carrier precursor, and then the carrier precursor may be aged. Examples of organic acids include citric acid, malic acid, tartaric acid, gluconic acid, acetic acid, ethylenediaminetetraacetic acid (EDTA), and diethylenetriamine pentaacetic acid (DTPA). Examples of sugars include monosaccharides, disaccharides, and polysaccharides.

(87) <<Shaping of Carrier Precursor>>

(88) The carrier precursor containing alumina hydrate and the additive oxide component raw materials are placed in, for example, a steam-jacketed double-arm kneader, heated, and kneaded to prepare a formable kneaded material. Then the kneaded material is formed into a desired shape, such as a cylindrical, trilobal, or quadrilobal shape, by extrusion molding, for example.

(89) (Step (2))

(90) In the step (2), the formed article of the carrier precursor produced in the step (1) is calcined to produce an inorganic oxide carrier. The formed article may be dried by heating at, for example, 70° C. to 150° C., preferably 90° C. to 130° C., before the calcination. The calcination temperature is, for example, 400° C. to 800° C., preferably 400° C. to 600° C. The calcination time is, for example, 0.5 to 10 hours, preferably 2 to 5 hours. An insufficient calcination temperature causes the organic additives to remain or causes the average pore diameter to decrease, which is not preferred. An excessively high calcination temperature results in a decrease in specific surface area, which is not preferred.

(91) (Step (3))

(92) In the step (3), an impregnating solution including the raw material for the metal component, an acid, and water is prepared, and then the inorganic oxide carrier is impregnated with the impregnating solution to support the raw material for the metal component on the inorganic oxide carrier.

(93) <Raw Material for Metal Component>

(94) The resulting carrier is brought into contact with the impregnating solution containing the raw material for the metal component. Examples of the raw material for the metal component include molybdenum trioxide, ammonium molybdate, cobalt nitrate, cobalt carbonate, nickel nitrate, and nickel carbonate.

(95) The amount of raw material for the metal component is set in such a manner that the amount of molybdenum and the amount of nickel and/or cobalt in the hydrotreating catalyst to be produced are within the ranges described above. The amount or composition of the raw material for the metal component is appropriately selected in accordance with the type of feedstock oil to be subjected to hydrotreatment or the application of the product oil.

(96) When the raw material for the metal component is supported on the inorganic oxide carrier, the impregnating solution in which the raw material for the metal component is dissolved is prepared, and then the raw material is supported on the carrier.

(97) <Impregnating Solution>

(98) When the impregnating solution is prepared, preferably, an inorganic acid or organic acid is used to set the pH of the impregnating solution to 4 or less, thereby dissolving the raw material for the metal component. Examples of inorganic acids include phosphoric acid and nitric acid. 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 diethylenetriamine pentaacetic acid (DTPA). In particular, citric acid or malic acid are suitably used.

(99) (Step (4))

(100) In the step (4), the inorganic oxide carrier on which the raw material for the metal component is supported is calcined to produce the hydrotreating catalyst according to an embodiment of the present invention.

(101) The calcination temperature is, for example, 400° C. to 800° C., preferably 400° C. to 700° C., more preferably 450° C. to 650° C. The calcination time is, for example, 0.5 to 10 hours, preferably to 8 hours. An excessively high calcination temperature results in a deterioration in catalytic activity due to the aggregation of the metal component, which is not preferred.

(102) The hydrotreating catalyst according to an embodiment of the present invention described above can be produced by a method for producing a hydrotreating catalyst according to an embodiment of the present invention.

(103) [Hydrotreating Method]

(104) A method for hydrotreating a heavy hydrocarbon oil (heavy oil) according to an embodiment of the present invention includes a step of hydrotreating a heavy hydrocarbon oil (heavy oil) in the presence of a hydrotreating catalyst according to an embodiment of the present invention.

(105) The heavy oil to be treated with the catalyst according to an embodiment of the present invention is mainly composed of a distillation residue of crude oil. The heavy oil has a wider molecular weight distribution than kerosene and gas oil fractions, and the characteristics of the heavy oil vary greatly, depending on the origin of the crude oil. Typical heavy oils from the Middle East and Central and South America have a high sulfur content or a high asphaltene content. Such heavy oils having a high asphaltene content contain high levels of residual carbon and impurity metals, such as vanadium and nickel. Heavy oils are subjected to a hydrorefining process with a hydrotreater for heavy oils and can be used as feedstocks for low-sulfur heavy oils or feedstocks for residue fluid catalytic crackers (RFCCs).

(106) Examples of the above heavy oils include, but are not limited to, high-density petroleum fractions, such as atmospheric residue (AR) and vacuum residue (VR) of crude oil, catalytic cracking residue, visbreaking oil, and bitumen. These heavy oils usually contain more than 1% by mass asphaltene. Asphaltene extracted from these heavy oils can also be used as feedstock oil. In an embodiment of the present invention, these may be used alone or in combination, as feedstock oil. For example, coker oil, synthetic crude oil, naphtha-cut crude oil, heavy gas oil, vacuum gas oil, LCO, gas-to-liquid (GTL) oil, or wax can be mixed with, for example, atmospheric residue, and the resulting mixture can be used as heavy oil for hydrotreatment.

(107) Regarding the distillation characteristics of a feedstock heavy oil, a heavy oil having a density of 0.90 to 1.05 g/cm.sup.3 and a sulfur content (sulfur concentration) of 1% to 6% by mass and containing 80% by mass of a component having a boiling point of 360° C. or higher is preferably used. The nitrogen content (nitrogen concentration) of the feedstock heavy oil is preferably more than 2,000 ppm by mass and 10,000 ppm or less by mass.

(108) The hydrotreatment with the catalyst according to an embodiment of the present invention is performed, for example, by filling a fixed-bed reactor with the catalyst in such a manner that the catalyst is stacked to form a demetallization section, a transition section, and a desulfurization section in the distribution direction, and passing heavy oil through the reactor in a hydrogen atmosphere under high-temperature and high-pressure conditions.

(109) The resulting processed oil is subjected to a catalytic cracking process with a fluid catalytic cracker, as needed. The catalytic cracking process with the fluid catalytic cracker may be performed using any known method and conditions with no particular limitations. For example, an amorphous catalyst, such as silica-alumina or silica-magnesia, or a zeolite catalyst, such as faujasite-type crystalline aluminosilicate, is used. A reaction temperature of about 450° C. to about 650° C., preferably 480° C. to 580° C., a regeneration temperature of about 550° C. to about 760° C., and a reaction pressure of about 0.1 MPa to about MPa, preferably 0.2 MPa to 2 MPa, may be selected, as appropriate. The product oil subjected to the catalytic cracking process with the fluid catalytic cracker, which is the final step, can be used as a feedstock for fuels and petrochemicals.

EXAMPLES

(110) Although the present invention will be described in more detail by means of examples, the present invention is not limited to these examples.

(111) <Method for Measuring Carrier Component Contents, Such as Aluminum, Phosphorus, Titanium, Zirconium, Boron, Silicon, and Magnesium Contents) and Metal Component Contents, Such as Molybdenum, Cobalt, and Nickel Contents>

(112) About 10 g of a catalyst for measurement was ground in a mortar. About 0.5 g of the ground sample was collected, heat-treated (200° C., 20 min), and calcined (700° C., 5 min). Then 2 g of Na.sub.2O.sub.2 and 1 g of NaOH were added thereto. The mixture was melted for 15 minutes. After dissolving the mixture by adding 25 mL of H.sub.2SO.sub.4 and 200 mL of water, the resulting solution was diluted to 500 mL with deionized water to prepare a sample. For the resulting sample, the component contents, excluding aluminum, were each measured on an oxide basis using an inductively coupled plasma (ICP) emission spectrometer (ICPS-8100, available from Shimadzu Corporation, analysis software: ICPS-8000). The aluminum content (in terms of Al.sub.2O.sub.3) was determined by subtracting the other component contents from the amount of the measured sample.

(113) <Method for Measuring Surface Area (Specific Surface Area N.sub.2) Determined by BET Single-Point Method for Measuring Nitrogen Adsorption/Desorption>

(114) About 30 mL of a catalyst for measurement was collected in a ceramic crucible (B-2 type), heat-treated at 500° C. for 1 hour, placed in a desiccator, and cooled to room temperature to provide a measurement sample. Subsequently, 1 g of this sample was collected, and then the specific surface area (m.sup.2/g) of the sample was measured by the BET method using a fully automated surface area measurement device (Model: MultiSorb 12, available from Yuasa Ionics Co., Ltd).

(115) <Method for Measuring Average Pore Diameter of Carrier>

(116) About 3 g of a carrier for measurement was collected in a ceramic crucible, heat-treated at 500° C. for 1 hour, placed in a desiccator, and cooled to room temperature to provide a measurement sample. Measurement was performed by a mercury intrusion method with Poremaster GT-60 available from Quantachrome Instruments (mercury contact angle: 150°, and surface tension: 480 dyn/cm). The average pore diameter was defined as a pore diameter corresponding to 50% of the pore volume.

(117) <Method for Measuring Pore Volume of Carrier>

(118) About 30 g of a carrier for measurement was collected in a ceramic crucible, heat-treated at 500° C. for 1 hour, placed in a desiccator, and cooled to room temperature to provide a measurement sample. The pore volume was measured by a pore-filling method with water.

(119) <Method for Measuring Amount of Nitrogen Monoxide Adsorbed on sulfided Catalyst>

(120) The amount of nitrogen monoxide adsorbed was measured using a fully automated catalyst gas adsorption measurement system (available from Okura Riken Co., Ltd). A mixed gas of helium gas and nitrogen monoxide gas (nitrogen monoxide concentration: 10% by volume) was introduced in pulses to a sulfided hydrotreating catalyst to measure the amount of nitrogen monoxide molecules adsorbed per gram of the hydrotreating catalyst. Specifically, about 0.2 g of the catalyst ground to 60 mesh or less was weighed and filled into a quartz cell. The catalyst was heated to 360° C. and subjected to sulfurization treatment for 1 hour by allowing a mixture containing 5% hydrogen sulfide by volume and 95% hydrogen by volume to flow therethrough at a flow rate of 0.2 L/min. The catalyst was then held at 340° C. for 1 hour to discharge physisorbed hydrogen sulfide from the system. Then nitrogen monoxide molecules were adsorbed with a mixed gas of helium gas and nitrogen monoxide gas at 50° C. The amount of nitrogen monoxide molecules adsorbed was measured with a thermal conductivity detector (TCD).

(121) <Measurement by Temperature-Programmed Reduction Method>

(122) In a temperature-programmed reduction method, a fully automated catalyst gas adsorption measurement system (available from Okura Riken Co., Ltd.) was used. First, 0.05 g of a catalyst that had been granulated to 250 to 710 μm was pretreated at 400° C. for 1 hour under a stream of argon gas and cooled to 50° C. The argon gas was switched to a hydrogen/argon mixed gas having a hydrogen concentration of 65%. The mixed gas was allowed to flow at a feed rate of 24 mL/min. The temperature was increased from 50° C. to 600° C. at 3° C./min. The flowing gas during the temperature increase was analyzed with a thermal conductivity detector (TCD) to obtain the hydrogen gas consumption spectrum. From the hydrogen gas consumption spectrum, the reduction peak temperature of a metal component was read.

(123) FIGURE is a graph of an example of the results of the analysis using the temperature-programmed reduction method. The horizontal axis represents the catalyst sample temperature. The vertical axis represents the relative value of the hydrogen gas consumption. In an embodiment of the present invention, the “reduction peak temperature” refers to the catalyst sample temperature at the point of the highest hydrogen consumption in the temperature range of lower than 450° C., as can be read in the example illustrated in FIGURE.

(124) <Method for Analyzing Hydrocarbon Oil>

(125) The sulfur concentration was measured in accordance with JIS K 2541-7. The nitrogen concentration was measured in accordance with JIS K 2609. The concentrations of metals (nickel and vanadium) were measured in accordance with JPI-5S-62 of the Japan Petroleum Institute. The residual carbon content was measured in accordance with JIS K 2270-2:2009. The density was measured in accordance with JIS K 2249-1. The distillation characteristics were measured in accordance with ASTM D2892.

Production Example 1: Preparation of Carrier D

(126) First, 60.4 kg of deionized water was placed in a tank equipped with a circulation line with two chemical inlets. Then 19.2 kg of an aqueous solution of aluminum sulfate (concentration: 7% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of an acidic aluminum salt, was added thereto under stirring. The resulting diluted aqueous solution was heated to 60° C. and circulated. The aqueous solution had a pH of 2.3. While stirring the diluted aqueous solution, 5.00 kg of an aqueous solution of titanyl sulfate (concentration: 5% by mass in terms of TiO.sub.2) and 1.04 kg of an aqueous solution of sodium silicate (water glass, concentration: 24% by mass in terms of SiO.sub.2) were sequentially added to the diluted aqueous solution to prepare an aqueous acidic aluminum salt solution (D1).

(127) Next, 14.3 kg of an aqueous solution of sodium aluminate (concentration: 22% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of a basic aluminum salt, was added to the aqueous acidic aluminum salt solution (D1) over a period of 60 minutes while the aqueous solution being stirred, circulated, and maintained at 60° C., thereby preparing a slurry. The pH of the slurry was adjusted to 9.5. The pH was adjusted by the addition of a 15% by mass aqueous ammonia solution or a 10% by mass aqueous solution of sulfuric acid, unless otherwise specified, including other production examples and comparative production examples. The resulting alumina-based composite oxide hydrate was washed with deionized water having a temperature of 60° C. to remove impurities, such as sodium and sulfate radicals, thereby providing a washed cake. The washed cake was adjusted to have an Al.sub.2O.sub.3 concentration of 8% by mass by the addition of deionized water. The cake was aged at 95° C. for 3 hours in an aging tank equipped with a reflux condenser and dehydrated to provide a cake-like alumina-based composite oxide hydrate (D).

(128) The cake-like alumina-based composite oxide hydrate (D) was kneaded in a steam-jacketed double-arm kneader and concentrated and kneaded until a predetermined moisture content (about 40% to 70%, also in other production examples and comparative production examples) was achieved. The resulting kneaded material was extruded into a quadrilobal columnar shape with a diameter of 1.7 mm using an extruder. The resulting molded articles were dried at 110° C. for 12 hours and then calcined at 500° C. for 3 hours to yield a carrier D. Table 1 presents the chemical composition of the carrier D.

Production Example 2: Preparation of Carrier E

(129) First, 64.1 kg of deionized water was placed in a tank equipped with a circulation line with two chemical inlets. Then 19.2 kg of an aqueous solution of aluminum sulfate (concentration: 7% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of an acidic aluminum salt, was added thereto under stirring. The resulting diluted aqueous solution was heated to 60° C. and circulated. The diluted aqueous solution had a pH of 2.3. While stirring the diluted aqueous solution, 1.65 kg of an aqueous solution of zirconium sulfate (concentration: 18.2% by mass in terms of ZrO.sub.2) and 0.83 kg of an aqueous solution of sodium silicate (concentration: 24% by mass in terms of SiO.sub.2) were sequentially added to the diluted aqueous solution to prepare an aqueous acidic aluminum salt solution (E1).

(130) Next, 14.3 kg of an aqueous solution of sodium aluminate (concentration: 22% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of a basic aluminum salt, was added to the aqueous acidic aluminum salt solution (E1) over a period of 60 minutes while the aqueous solution being stirred, circulated, and maintained at 60° C., thereby preparing a slurry. The pH of the slurry was adjusted to 9.5. The resulting alumina-based composite oxide hydrate was washed with deionized water having a temperature of 60° C. to remove impurities, such as sodium and sulfate radicals, thereby providing a washed cake. The washed cake was adjusted to have an Al.sub.2O.sub.3 concentration of 8% by mass by the addition of deionized water. The cake was aged at 95° C. for 3 hours in an aging tank equipped with a reflux condenser and dehydrated to provide a cake-like alumina-based composite oxide hydrate (E).

(131) A carrier E was produced as in Production example 1, except that the alumina-based composite oxide hydrate (D) was changed to the alumina-based composite oxide hydrate (E). Table 1 presents the chemical composition of the carrier E.

Production Example 3: Preparation of Carrier F

(132) First, 63.8 kg of deionized water was placed in a tank equipped with a circulation line with two chemical inlets. Then 20.5 kg of an aqueous solution of aluminum sulfate (concentration: 7% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of an acidic aluminum salt, was added thereto under stirring. The resulting diluted aqueous solution was heated to 60° C. and circulated. The diluted aqueous solution had a pH of 2.3. While stirring the diluted aqueous solution, 0.08 kg of phosphoric acid (concentration: 61.6% by mass in terms of P.sub.2O.sub.5) and 0.63 kg of an aqueous solution of sodium silicate (concentration: 24% by mass in terms of SiO.sub.2) were sequentially added to the diluted aqueous solution to prepare an aqueous acidic aluminum salt solution (F1).

(133) Next, 15.3 kg of an aqueous solution of sodium aluminate (concentration: 22% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of a basic aluminum salt, was added to the aqueous acidic aluminum salt solution (F1) over a period of 60 minutes while the aqueous solution being stirred, circulated, and maintained at 60° C., thereby preparing a slurry. The pH of the slurry was adjusted to 9.5. The resulting alumina-based composite oxide hydrate was washed with deionized water having a temperature of 60° C. to remove impurities, such as sodium and sulfate radicals, thereby providing a washed cake. The washed cake was adjusted to have an Al.sub.2O.sub.3 concentration of 10% by mass by the addition of deionized water. The cake was aged at 95° C. for 3 hours in an aging tank equipped with a reflux condenser and dehydrated to provide a cake-like alumina-based composite oxide hydrate (F).

(134) A carrier F was produced as in Production example 1, except that the alumina-based composite oxide hydrate (D) was changed to the alumina-based composite oxide hydrate (F). Table 1 presents the chemical composition of the carrier F.

Production Example 4: Preparation of Carrier G

(135) First, 59.6 kg of deionized water was placed in a tank equipped with a circulation line with two chemical inlets. Then 20.3 kg of an aqueous solution of aluminum sulfate (concentration: 7% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of an acidic aluminum salt, was added thereto under stirring. The resulting diluted aqueous solution was heated to 60° C. and circulated. The diluted aqueous solution had a pH of 2.3. While stirring the diluted aqueous solution, 5.0 kg of aqueous solution of magnesium sulfate (concentration: 5% by mass in terms of MgO) was added to the diluted aqueous solution to prepare an aqueous acidic aluminum salt solution (G1).

(136) Next, 15.2 kg of an aqueous solution of sodium aluminate (concentration: 22% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of a basic aluminum salt, was added to the aqueous acidic aluminum salt solution (G1) over a period of 60 minutes while the aqueous solution being stirred, circulated, and maintained at 60° C., thereby preparing a slurry. The pH of the slurry was adjusted to 9.5. The resulting alumina-based composite oxide hydrate was washed with deionized water having a temperature of 60° C. to remove impurities, such as sodium and sulfate radicals, thereby providing a washed cake. The washed cake was adjusted to have an Al.sub.2O.sub.3 concentration of 7% by mass by the addition of deionized water. The cake was aged at 95° C. for 3 hours in an aging tank equipped with a reflux condenser and dehydrated to provide a cake-like alumina-based composite oxide hydrate (G).

(137) A carrier G was produced as in Production example 1, except that the alumina-based composite oxide hydrate (D) was changed to the alumina-based composite oxide hydrate (G). Table 1 presents the chemical composition of the carrier G.

Production Example 5: Preparation of Carrier H

(138) First, 60.9 kg of deionized water was placed in a tank equipped with a circulation line with two chemical inlets. Then 20.7 kg of an aqueous solution of aluminum sulfate (concentration: 7% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of an acidic aluminum salt, was added thereto under stirring. The resulting diluted aqueous solution was heated to 60° C. and circulated. The diluted aqueous solution had a pH of 2.3. While stirring the diluted aqueous solution, 266 g of boric acid was added to the diluted aqueous solution to prepare an aqueous acidic aluminum salt solution (H1).

(139) Next, 15.5 kg of an aqueous solution of sodium aluminate (concentration: 22% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of a basic aluminum salt, was added to the aqueous acidic aluminum salt solution (H1) over a period of 60 minutes while the aqueous solution being stirred, circulated, and maintained at 60° C., thereby preparing a slurry. The pH of the slurry was adjusted to 9.5. The resulting alumina-based composite oxide hydrate was washed with deionized water having a temperature of 60° C. to remove impurities, such as sodium and sulfate radicals, thereby providing a washed cake. The washed cake was adjusted to have an Al.sub.2O.sub.3 concentration of 10% by mass by the addition of deionized water. The cake was aged at 95° C. for 3 hours in an aging tank equipped with a reflux condenser and dehydrated to provide a cake-like alumina-based composite oxide hydrate (H).

(140) A carrier H was produced as in Production example 1, except that the alumina-based composite oxide hydrate (D) was changed to the alumina-based composite oxide hydrate (H). Table 1 presents the chemical composition of the carrier H.

Production Example 6: Preparation of Carrier I

(141) First, 60.2 kg of deionized water was placed in a tank equipped with a circulation line with two chemical inlets. Then 19.8 kg of an aqueous solution of aluminum sulfate (concentration: 7% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of an acidic aluminum salt, was added thereto under stirring. The resulting diluted aqueous solution was heated to 60° C. and circulated. The diluted aqueous solution had a pH of 2.3. While stirring the diluted aqueous solution, 5.00 kg of an aqueous solution of titanyl sulfate (concentration: 5% by mass in terms of TiO.sub.2) and 162 g of phosphoric acid (concentration: 61.6% by mass in terms of P.sub.2O.sub.5) were sequentially added to the diluted aqueous solution to prepare an aqueous acidic aluminum salt solution (I1).

(142) Next, 14.8 kg of an aqueous solution of sodium aluminate (concentration: 22% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of a basic aluminum salt, was added to the aqueous acidic aluminum salt solution (I1) over a period of 60 minutes while the aqueous solution being stirred, circulated, and maintained at 60° C., thereby preparing a slurry. The pH of the slurry was adjusted to 9.5. The resulting alumina-based composite oxide hydrate was washed with deionized water having a temperature of 60° C. to remove impurities, such as sodium and sulfate radicals, thereby providing a washed cake. The washed cake was adjusted to have an Al.sub.2O.sub.3 concentration of 8% by mass by the addition of deionized water. The cake was aged at 95° C. for 3 hours in an aging tank equipped with a reflux condenser and dehydrated to provide a cake-like alumina-based composite oxide hydrate (I).

(143) A carrier I was produced as in Production example 1, except that the alumina-based composite oxide hydrate (D) was changed to the alumina-based composite oxide hydrate (I). Table 1 presents the chemical composition of the carrier I.

Production Example 7: Preparation of Carrier J

(144) First, 63.4 kg of deionized water was placed in a tank equipped with a circulation line with two chemical inlets. Then 20.5 kg of an aqueous solution of aluminum sulfate (concentration: 7% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of an acidic aluminum salt, was added thereto under stirring. The resulting diluted aqueous solution was heated to 60° C. and circulated. The diluted aqueous solution had a pH of 2.3. While stirring the diluted aqueous solution, 0.08 kg of phosphoric acid (concentration: 61.6% by mass in terms of P.sub.2O.sub.5) was added to the diluted aqueous solution to prepare an aqueous acidic aluminum salt solution (J1).

(145) Next, 15.3 kg of an aqueous solution of sodium aluminate (concentration: 22% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of a basic aluminum salt, was added to the aqueous acidic aluminum salt solution (J1) over a period of 60 minutes while the aqueous solution being stirred, circulated, and maintained at 60° C., and then 0.75 kg of a silica sol (Cataloid SN, available from JGC Catalysts and Chemicals Ltd., concentration: 20% by mass in terms of SiO.sub.2) was added thereto, thereby preparing a slurry. The pH of the slurry was adjusted to 9.5. The resulting alumina-based composite oxide hydrate was washed with deionized water having a temperature of 60° C. to remove impurities, such as sodium and sulfate radicals, thereby providing a washed cake. The washed cake was adjusted to have an Al.sub.2O.sub.3 concentration of 10% by mass by the addition of deionized water. The cake was aged at 95° C. for 3 hours in an aging tank equipped with a reflux condenser and dehydrated to provide a cake-like alumina-based composite oxide hydrate (J).

(146) A carrier J was produced as in Production example 1, except that the alumina-based composite oxide hydrate (D) was changed to the alumina-based composite oxide hydrate (J). Table 1 presents the chemical composition of the carrier J.

Comparative Production Example 1: Preparation of Carrier A

(147) First, 31 kg of deionized water was placed in a tank equipped with a steam jacket. Then 9.1 kg of an aqueous solution of sodium aluminate (concentration: 22% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of a basic aluminum salt, was added thereto under stirring. The resulting aqueous basic aluminum salt solution (A1) was heated to 60° C. The aqueous basic aluminum salt solution (A1) had a pH of 13.

(148) Next, 40 kg of an aqueous solution of aluminum sulfate (concentration: 2.5% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of an acidic aluminum salt, was added to the aqueous basic aluminum salt solution (A1) with a roller pump at a constant feed rate (addition time: 10 minutes) until the pH of the resulting aqueous solution was 7.2. The resulting alumina hydrate was washed with deionized water having a temperature of 60° C. to remove impurities, such as sodium and sulfate radicals, thereby providing a washed cake. The washed cake-like slurry was diluted with deionized water so as to have an aluminum concentration of 10% by mass in terms of Al.sub.2O.sub.3. The pH was adjusted to 10.5 with a 15% by mass aqueous ammonia solution. The resulting mixture was aged at 95° C. for 10 hours in an aging tank equipped with a reflux condenser and dehydrated to provide a cake-like alumina hydrate (A).

(149) A carrier A was produced as in Production example 1, except that the alumina-based composite oxide hydrate (D) was changed to the alumina hydrate (A). Table 1 presents the chemical composition of the carrier A.

Comparative Production Example 2: Preparation of Carrier B

(150) First, 62.7 kg of deionized water was placed in a tank equipped with a circulation line with two chemical inlets. Then 21.3 kg of an aqueous solution of aluminum sulfate (concentration: 7% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of an acidic aluminum salt, was added thereto under stirring. The resulting aqueous acidic aluminum salt solution (B1) was heated to 60° C. and circulated. The aqueous acidic aluminum salt solution (B1) had a pH of 2.3.

(151) Next, 15.9 kg of an aqueous solution of sodium aluminate (concentration: 22% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of a basic aluminum salt, was added to the aqueous acidic aluminum salt solution (B1) over a period of 60 minutes while the aqueous solution being stirred, circulated, and maintained at 60° C., thereby preparing an alumina hydrate (B). After the addition of the aqueous solution of sodium aluminate, the pH of the slurry was adjusted to 9.5. The resulting alumina hydrate was washed with deionized water having a temperature of 60° C. to remove impurities, such as sodium and sulfate radicals, thereby providing a washed cake. The washed cake was adjusted to have an Al.sub.2O.sub.3 concentration of 10% by mass by the addition of deionized water. The cake was aged at 95° C. for 3 hours in an aging tank equipped with a reflux condenser and dehydrated to provide a cake-like alumina hydrate (B).

(152) A carrier B was produced as in Comparative production example 1, except that the alumina hydrate (A) was changed to the alumina hydrate (B). Table 1 presents the chemical composition of the carrier B.

Comparative Production Example 3: Preparation of Carrier C

(153) First, 31 kg of deionized water was placed in a tank equipped with a steam jacket. Then 8.2 kg of an aqueous solution of sodium aluminate (concentration: 22% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of a basic aluminum salt, was added thereto under stirring. The resulting diluted aqueous solution was heated to 60° C. The diluted aqueous solution had a pH of 13. While stirring the diluted aqueous solution, 3.00 kg of an aqueous solution of titanyl sulfate (concentration: 5% by mass in terms of TiO.sub.2) and 0.63 kg of an aqueous solution of sodium silicate (concentration: 24% by mass in terms of SiO.sub.2) were sequentially added to the diluted aqueous solution. Then 36.0 kg of an aqueous solution of aluminum sulfate (concentration: 2.5% by mass in terms of Al.sub.2O.sub.3), which was an aqueous solution of an acidic aluminum salt, was added thereto with a roller pump at a constant feed rate (addition time: 10 minutes) until the pH of the resulting aqueous solution was 7.2.

(154) The resulting alumina-based composite oxide hydrate was washed with deionized water having a temperature of 60° C. to remove impurities, such as sodium and sulfate radicals, thereby providing a washed cake. The washed cake-like slurry was diluted with deionized water so as to have an aluminum concentration of 10% by mass in terms of Al.sub.2O.sub.3. The pH was adjusted to 10.5 with a 15% by mass aqueous ammonia solution. The resulting mixture was aged at 95° C. for 10 hours in an aging tank equipped with a reflux condenser and dehydrated to provide a cake-like alumina-based composite oxide hydrate (C).

(155) A carrier C was produced as in Comparative production example 1, except that the alumina hydrate (A) was changed to the alumina-based composite oxide hydrate (C). Table 1 presents the chemical composition of the carrier C.

(156) <Preparation of Impregnating Solution>

(157) Preparation of Impregnating Solution a

(158) First, 73.2 g of molybdenum trioxide and 33.3 g of nickel carbonate were suspended in 350 mL of ion-exchange water. The suspension was heated at 90° C. for 5 hours using a suitable reflux condenser so as not to decrease the volume of the liquid. Then 29.7 g of phosphoric acid and 27.4 g of citric acid were added thereto for dissolution, thereby preparing an impregnating solution a.

(159) Preparation of Impregnating Solution b

(160) An impregnating solution b was prepared in the same manner as the method for preparing the impregnating solution a, except that nickel carbonate was changed to 33.3 g of cobalt carbonate.

(161) Preparation of Impregnating Solution c

(162) An impregnating solution c was prepared in the same manner as the method for preparing the impregnating solution a, except that nickel carbonate was changed to 19.9 g of cobalt carbonate and 11.1 g of nickel carbonate.

(163) Preparation of Impregnating Solution d

(164) An impregnating solution d was prepared in the same manner as the method for preparing the impregnating solution a, except that nickel carbonate was changed to 10.0 g of cobalt carbonate and 22.2 g of nickel carbonate.

(165) Preparation of Impregnating Solution e

(166) First, 45.5 g of molybdenum trioxide and 20.7 g of nickel carbonate were suspended in 350 mL of ion-exchange water. The suspension was heated at 90° C. for 5 hours using a suitable reflux condenser so as not to decrease the volume of the liquid. Then 18.5 g of phosphoric acid and 17.1 g of citric acid were added thereto for dissolution, thereby preparing an impregnating solution e.

(167) Preparation of Impregnating Solution f

(168) First, 96.9 g of molybdenum trioxide and 44.6 g of nickel carbonate were suspended in 350 mL of ion-exchange water. The suspension was heated at 90° C. for 5 hours using a suitable reflux condenser so as not to decrease the volume of the liquid. Then 39.9 g of phosphoric acid and 36.8 g of citric acid were added thereto for dissolution, thereby preparing an impregnating solution f.

Comparative Example 1: Preparation of Hydrodesulfurization Catalyst (1)

(169) An appropriate amount of deionized water was added to the impregnating solution a in such a manner that the volume of the resulting impregnating solution a was equal to the total pore volume of 500 g of the carrier A. Then 500 g of the carrier A was spray-impregnated with the resulting impregnating solution a. The resulting carrier was dried at 250° C. and calcined in an electric furnace at 550° C. for 1 hour to produce a desulfurization catalyst (1) (hereinafter, also referred to simply as a “catalyst (1)”. The same applies to the following examples.

Comparative Examples 2 to 6 and Examples 1 to 12: Preparation of Hydrodesulfurization Catalysts (2) to (18)

(170) Catalysts (2) to (18) were prepared in the same manner as in Comparative Example 1, except that the carriers and the impregnating solutions prepared as described above were combined as described in Tables 1 to 3.

(171) <Evaluation of Catalyst Performance>

(172) Commercially available demetallization catalysts, transition catalysts, and desulfurization catalysts, and catalysts of Examples or Comparative Examples were loaded into a fixed-bed flow reactor (volume of catalyst loaded: 350 mL) in the following order:

(173) 35 mL of a commercially available demetallization catalyst (CDS-RS110, available from JGC Catalysts and Chemicals Ltd.),

(174) 35 mL of a commercially available demetallization catalyst (CDS-RS210, available from JGC Catalysts and Chemicals Ltd.),

(175) 70 mL of a commercially available transition catalyst (CDS-RS420, available from JGC Catalysts and Chemicals Ltd.),

(176) 105 mL of a commercially available desulfurization catalyst (CDS-R38C, available from JGC Catalysts and Chemicals Ltd.), and

(177) 105 mL of the catalyst of Example or Comparative example.

(178) The loaded catalysts were subjected to pre-sulfurization treatment in order to activate the catalysts by desorbing the oxygen atoms contained in the catalysts. This treatment was performed in the usual manner, i.e., by passing a sulfur compound-containing liquid or gas through a controlled reaction vessel at a temperature of 200° C. to 400° C. in an atmosphere having a hydrogen pressure of normal to 100 MPa.

(179) A heavy oil (density at 15° C.: 0.9741 g/cm.sup.3, sulfur content: 4.06% by mass, metal (Ni+V) content: 85.1 ppm by mass, nitrogen content: 2,075 ppm by mass, asphaltene content: 4.2% by mass, and residual carbon content: 10.7% by mass) was introduced into the fixed-bed flow reactor and subjected to hydrotreatment. The reaction conditions included a hydrogen partial pressure of 13.5 MPa, a liquid hourly space velocity of 0.3 h.sup.−1, a hydrogen-oil ratio of 800 Nm.sup.3/kl. The sulfur content, the nitrogen content, and the residual carbon content in the final product oil were analyzed at different reaction temperatures in the range of 360° C. to 380° C.

(180) In the activity test, the reaction rate constant was determined from an Arrhenius plot. The reaction rate constant obtained from the evaluation results when the catalyst (1) was loaded in the desulfurization catalyst section at a reaction temperature of 370° C. was defined as 100%. The desulfurization activity, the denitrogenation activity, and the residual carbon removal activity (relative activity) at 370° C. were calculated when other catalysts were loaded in the desulfurization catalyst section. The reaction rate constant was determined on the basis of equation (1) below.
K.sub.n=LHSV×1/(n−1)×(1/P.sup.n-1−1/F.sup.n-1)  (1)
where
Kn: Reaction rate constant,
n: The desulfurization reaction rate, the denitrogenation reaction rate, or the residual carbon removal reaction rate is proportional to the power of the concentration of sulfur, nitrogen, or residual carbon in the feedstock oil, respectively (n=2.0 for the desulfurization reaction, n=1.0 for the denitrogenation reaction, and n=1.0 for the residual carbon removal reaction),
P: The sulfur concentration (% by mass), the nitrogen concentration (% by mass), or the residual carbon concentration (% by mass) in the processed oil,
F: The sulfur concentration (% by mass), the nitrogen concentration (% by mass), or the residual carbon concentration (% by mass) in the feedstock oil, and
LHSV: Liquid hourly space velocity (hr.sup.−1).

(181) Tables 1 to 3 present the results. The catalyst (1) of Comparative example contained the carrier consisting only of alumina and exhibited a reduction peak temperature of lower than the value A. Although the catalyst (1) had the same pore characteristics as the catalyst of Example, the catalyst (1) did not have superior catalytic activity.

(182) The catalyst (2) of Comparative example contained molybdenum and cobalt as the metal component and the carrier consisting only of alumina. The catalyst (2) was inferior in catalytic activity to the catalyst (14) of Example, which had a comparable amount of the metal component and exhibited a reduction peak temperature of higher than the value A.

(183) The catalyst (3) of Comparative example contained the carrier component consisting only of alumina and exhibited a reduction peak temperature of lower than the value A. The catalyst (3) had different pore characteristics from the catalyst of Example and did not have superior catalytic activity.

(184) The catalyst (4) of Comparison example contained the carrier composed of alumina-titania-silica composite oxide and had the same pore characteristics as in Example. However, the catalyst (4) exhibited a reduction peak temperature of lower than the value A and did not have superior catalytic activity.

(185) Although both catalysts (9) and (13) had almost the same chemical composition, the presence of the silica component was considered to be different because the catalyst (9) was prepared using sodium silicate and the catalyst (13) was prepared using the silica sol. However, both catalysts (9) and (13) exhibited reduction peak temperatures of higher than the value A. Other physical properties thereof were within the scope disclosed in the present invention. These catalysts exhibited superior catalytic activity.

(186) All other catalysts of Examples exhibited high desulfurization, denitrogenation, and residual carbon removal activities.

(187) In Tables 2 and 3, the catalytic activities at different amounts of active metals are compared.

(188) The catalyst (5) of Comparative example had a small amount of metal component, contained the carrier component consisting only of alumina, and exhibited a reduction peak temperature of lower than the value A. In contrast, the catalyst (17) of Example, which had the same amount of metal component as the catalyst (5), contained the composite oxide carrier, and exhibited a reduction peak temperature of higher than the value A, was superior in catalytic performance to the catalyst (5).

(189) Comparison of the catalysts (6) and (18) indicates that even in the case of a large amount of metal component, the catalyst exhibits superior catalytic activity when the reduction peak temperature is higher than the value A.

(190) TABLE-US-00001 TABLE 1-1 Comparative example 1 2 3 4 Catalyst Catalyst (1) Catalyst (2) Catalyst (3) Catalyst (4) Carrier A A B C Impregnating solution a b a a Carrier Al.sub.2O.sub.3 content % by mass 100 100 100 89.8 composition (balance) TiO.sub.2 content % by mass 5.1 ZrO.sub.2 content % by mass SiO.sub.2 content % by mass 5.1 P.sub.2O.sub.5 content % by mass MgO content % by mass B.sub.2O.sub.3 content % by mass Carrier Average pore nm 12.8 12.8 13.9 10.7 characteristics diameter of carrier Sum of pore % 58 58 47 61 volumes of pores with pore diameter in range of ±2 nm of average pore diameter Sum of pore % 5 6 12 4 volumes of pores with pore diameter in range of 20 nm or more Pore volume ml/g 0.86 0.86 0.88 0.83 of carrier Catalyst MoO.sub.3 content % by mass 12 12 12 12 composition CoO content % by mass 3.0 NiO content % by mass 3.0 3.0 3.0 Catalyst Specific surface m.sup.2/g 218 209 201 263 characteristics area of catalyst Amount of ml/g 5.8 6.3 5.7 5.2 NO adsorbed on catalyst Value A ° C. 351 376 351 351 Peak temperature ° C. 347 373 346 348 in temperature- programmed reduction Catalytic Relative % 100 108 98 94 activity desulfurization activity Relative % 100 92 91 106 denitrogenation activity Relative residual % 100 91 93 92 carbon removal activity

(191) TABLE-US-00002 TABLE 1-2 Example 1 2 3 4 5 6 7 8 9 10 Catalyst Catalyst Catalyst Catalyst Catalyst Catalyst Catalyst Catalyst Catalyst Catalyst Catalyst (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) Carrier D E F G H I J D D D Impregnating a a a a a a a b c d solution Carrier Al.sub.2O.sub.3 content % by mass 90.1 90 95.9 95.2 96.9 93.1 95.9 90.1 90.1 90.1 composition (balance) TiO.sub.2 content % by mass 4.8 4.9 4.8 4.8 4.8 ZrO.sub.2 content % by mass 6.1 SiO.sub.2 content % by mass 5.1 3.9 3.2 3.1 5.1 5.1 5.1 P.sub.2O.sub.5 content % by mass 0.9 2.0 1.0 MgO content % by mass 4.8 B.sub.2O.sub.3 content % by mass 3.1 Carrier Average pore nm 11.2 10.6 13.1 9.8 9.4 12.1 12.8 11.2 11.2 11.2 characteristics diameter of carrier Sum of pore % 68 64 67 63 59 56 62 68 68 68 volumes of pores with pore diameter in range of ±2 nm of average pore diameter Sum of pore % 5 6 6 4 3 8 7 5 5 5 volumes of pores with pore diameter in range of 20 nm or more Pore volume ml/g 0.78 0.72 0.83 0.71 0.71 0.82 0.85 0.78 0.78 0.78 of carrier Catalyst MoO.sub.3 content % by mass 12 12 12 12 12 12 12 12 12 12 composition CoO content % by mass 3.0 2.0 1.0 NiO content % by mass 3.0 3.0 3.0 3.0 3.0 3.0 3.0 1.1 2.1 Catalyst Specific surface m.sup.2/g 287 254 291 265 301 241 274 291 274 265 characteristics area of catalyst Amount of ml/g 5.5 5.8 5.2 5.2 5.4 6.5 5.3 6.5 6.5 5.7 NO adsorbed on catalyst Value A ° C. 351 351 351 351 351 351 351 376 367 359 Peak temperature ° C. 360 356 358 356 355 356 356 380 370 363 in temperature- programmed reduction Catalytic Relative % 114 109 113 112 110 118 112 116 116 111 activity desulfurization activity Relative % 131 127 130 126 127 114 124 117 114 127 denitrogenation activity Relative residual % 112 108 110 104 107 104 112 103 102 107 carbon removal activity

(192) TABLE-US-00003 TABLE 2 Comparative Example example 5 11 Catalyst Catalyst (5) Catalyst (17) Carrier A D Impregnating solution e e Carrier Al.sub.2O.sub.3 content (balance) % by mass 100 90.1 composition TiO.sub.2 content % by mass 4.8 ZrO.sub.2 content % by mass SiO.sub.2 content % by mass 5.1 P.sub.2O.sub.5 content % by mass MgO content % by mass B.sub.2O.sub.3 content % by mass Carrier Average pore diameter of carrier nm 12.8 11.2 characteristics Sum of pore volumes of pores with pore % 58 68 diameter in range of ±2 nm of average pore diameter Sum of pore volumes of pores with pore % 5 5 diameter in range of 20 nm or more Pore volume of carrier ml/g 0.86 0.78 Catalyst MoO.sub.3 content % by mass 8 8 composition CoO content % by mass NiO content % by mass 2.0 2.0 Catalyst Specific surface area of catalyst m.sup.2/g 229 295 characteristics Amount of NO adsorbed on catalyst ml/g 5.1 5.1 Value A ° C. 347 347 Peak temperature in temperature- ° C. 341 355 programmed reduction Catalytic Relative desulfurization activity % 81 88 activity Relative denitrogenation activity % 89 94 Relative residual carbon removal activity % 84 91

(193) TABLE-US-00004 TABLE 3 Comparative Example example 6 12 Carrier Catalyst Catalyst (6) Catalyst (18) composition Carrier A D Impregnating solution f f Carrier Al.sub.2O.sub.3 content (balance) % by mass 100 90.1 characteristics TiO.sub.2 content % by mass 4.8 ZrO.sub.2 content % by mass SiO.sub.2 content % by mass 5.1 P.sub.2O.sub.5 content % by mass MgO content % by mass B.sub.2O.sub.3 content % by mass Average pore diameter of carrier nm 12.8 11.2 Sum of pore volumes of pores with pore % 58 68 diameter in range of ±2 nm of average pore diameter Sum of pore volumes of pores with pore % 8 5 diameter in range of 20 nm or more Pore volume of carrier ml/g 0.86 0.78 Catalyst MoO.sub.3 content % by mass 15 15 composition CoO content % by mass NiO content % by mass 3.8 3.8 Catalyst Specific surface area of catalyst m.sup.2/g 199 261 characteristics Amount of NO adsorbed on catalyst ml/g 6.4 6.3 Value A ° C. 354 354 Peak temperature in temperature- ° C. 349 364 programmed reduction Catalytic Relative desulfurization activity % 107 116 activity Relative denitrogenation activity % 105 109 Relative residual carbon removal activity % 104 112