JP5654720B2 - Hydrodesulfurization catalyst and hydrodesulfurization method for kerosene fraction - Google Patents

Description

  The present invention relates to a hydrodesulfurization catalyst for a kerosene fraction and a hydrodesulfurization method using the hydrodesulfurization catalyst.

Regarding the desulfurization of kerosene fraction, since there are few substances that inhibit the hydrodesulfurization reaction, desulfurization is relatively easy. Until now, there has been no hydrodesulfurization catalyst specially developed for kerosene fractions. The desulfurization catalyst is used as it is (see Patent Document 1), or the regenerated catalyst is used for hydrodesulfurization of kerosene fractions and diesel oil fractions, and the catalyst extracted from the reaction tower is subjected to regeneration treatment such as decoking. It has been. These catalysts do not require replacement for a long time and have a track record of being used successfully.
However, in recent years, in relation to stricter environmental regulations for gasoline and diesel oil, and from the viewpoint of producing low sulfur kerosene used by mixing with diesel oil, the sulfur content in kerosene is also required to be 10 ppm by mass or less. It has been.
In order to reduce the sulfur content of the kerosene fraction to 10 ppm by mass or less using a conventional catalyst, it is necessary to increase the reaction temperature and the kerosene may be colored. Depending on the conditions, the Saebold color may be less than +30, and the value as a product is reduced.

In addition, attempts have been made to obtain highly active catalysts by controlling the pore structure, and those that exhibit a high desulfurization rate in hydrodesulfurization reactions such as vacuum gas oil, straight-run gas oil, kerosene have been proposed (for example, (See Patent Document 2, Claims and Examples). However, the catalyst disclosed here has an average pore diameter of 6 to 9 nm, and there are almost no pores having a pore diameter of 10 nm or more (the proportion of pore volume occupied by pores having a pore diameter of 10 nm or more is extremely high). Although it is a small catalyst, it has become clear that its activity as a desulfurization catalyst for kerosene is insufficient to reduce the sulfur content to 10 mass ppm or less as will be described later.
In addition, a hydrotreating catalyst in which the support is a refractory inorganic oxide and / or activated carbon containing titanium and a basic oxide and the support has a pore diameter in the range of 8 to 25 nm has been proposed. It is disclosed that it is used for deep desulfurization (sulfur content of 10 mass ppm or less) (see Patent Document 3). Although the catalyst disclosed here has a high desulfurization rate, a catalyst and a hydrotreating method having further superior performance as a catalyst for desulfurization of kerosene have been desired.

Japanese Patent No. 2854484 JP 2002-28491 A JP 2004-74148 A

  The present invention has been made under such circumstances, and provides a hydrodesulfurization catalyst for a kerosene fraction that has a high desulfurization rate and is not colored, and a hydrodesulfurization method for a kerosene fraction using the catalyst. For the purpose.

As a result of intensive studies to achieve the above object, the present inventors have found that a hydrodesulfurization catalyst having a specific pore distribution can solve the above problems. The present invention has been completed based on such findings.
That is, the present invention
(1) Molybdenum as an active metal on an alumina carrier is supported by 15% by mass or more on an oxide basis, 1-10% by mass of nickel on an oxide basis, and 1-10% by mass of phosphorus as an active component on an oxide basis , A catalyst containing no cobalt, the volume of pores having a diameter of 10 nm or more is 60% or more of the total pore volume, and has one or more pore distribution peaks in the range of pore diameters of 11 to 20 nm, And a hydrodesulfurization catalyst for a kerosene fraction having a specific surface area of 100 to 200 m ² / g,
(2) A hydrodesulfurization method for a kerosene fraction, wherein the catalyst described in 1 is filled in an area of 50% downstream of the reactor in an amount of 20% by volume or more of the total amount of catalyst,
(3) A hydrodesulfurization method for a kerosene fraction, wherein the catalyst described in 1 above is charged in the downstream of the reactor at 20% by volume or more of the total catalyst amount,
(4) A hydrodesulfurization method for a kerosene fraction in which the 4-6 ring aromatic compound of kerosene is 15 mass μg / kg or less using the catalyst described in 1 above,
(5) A hydrodesulfurization method for a kerosene fraction in which the sulfur content of kerosene is 10 mass ppm or less using the catalyst described in 1 above,
(6) A hydrodesulfurization method for a kerosene fraction in which the sulfur content of kerosene is 1 mass ppm or less using the catalyst according to 1 above,
(7) The hydrodesulfurization method for a kerosene fraction according to 2 or 3 above, wherein the sulfur content of kerosene is 10 mass ppm or less,
(8) The hydrodesulfurization method for a kerosene fraction as described in 2 or 3 above, wherein the kerosene sulfur content is 1 mass ppm or less,
Is to provide.

  According to the hydrodesulfurization catalyst of the present invention, uncolored kerosene having a high desulfurization rate, a sulfur content of 10 mass ppm or less, and a Saybolt color +30 or more can be efficiently produced.

The hydrodesulfurization catalyst of the present invention is a catalyst in which an active metal is supported on a support, and the volume of pores having a diameter of 10 nm or more is 60% or more of the total pore volume.
In hydrodesulfurization of light oil, since there are many substances in the reaction system that inhibit the hydrodesulfurization reaction such as nitrogen, aroma, hydrogen sulfide, and ammonia, compared to the diffusion rate of sulfur compounds in the catalyst. The hydrodesulfurization rate of sulfur compounds is relatively slow. Accordingly, the hydrodesulfurization reaction of sulfur compounds is generally the rate-limiting step. In a reaction system having such a rate-determining step, in order to improve the activity of the catalyst, the specific surface area is increased by reducing the pore diameter to, for example, 10 nm or less, and the active metal is in a more highly dispersed state ( Increasing the number of active points) is widely performed. In other words, in the hydrodesulfurization reaction of light oil, even if the pore size is reduced and the diffusion rate is somewhat slowed, diffusion control will not be achieved. This leads to dispersion, that is, improvement in catalyst activity.

However, when such a catalyst is applied to hydrodesulfurization of a kerosene fraction, in the hydrodesulfurization of kerosene, substances that inhibit the above-mentioned hydrodesulfurization reaction do not exist in the reaction system. The reaction rate is considered to be faster than the hydrodesulfurization reaction of light oil. As a result, in the desulfurization reaction of the kerosene fraction, a situation occurs in which the diffusion rate of the sulfur compound into the catalyst cannot be said to be faster than the hydrodesulfurization reaction. In conventional hydrodesulfurization of kerosene fractions, the sulfur content of the product has remained at a desulfurization level of several tens to 100 ppm by mass, so it is not noticeable that the diffusion rate of sulfur compounds is slower than the hydrodesulfurization rate. However, when desulfurization up to 10 mass ppm or less is required even in the kerosene fraction, it always occurs that the diffusion rate of the sulfur compound is significantly slower than the hydrodesulfurization rate.
In particular, hydrodesulfurization of kerosene is easier than hydrodesulfurization of light oil, and is operated under severe conditions such as high liquid space velocity (LHSV) and low reaction pressure. Therefore, in order to lower the sulfur content in kerosene to 10 ppm by mass or less, it is necessary to increase the reaction temperature by 10 ° C. or more, for example, compared to the conventional case of several tens to 100 ppm by mass.
At this time, since the diffusion rate of the sulfur compound is slower than the hydrodesulfurization rate, a phenomenon occurs in which the sulfur content does not decrease much with increasing the temperature. In this case, 10 to several hundred mass μg / kg of a small amount of coloring substances derived from polycyclic aromatics, particularly 4 to 6 ring aromatic compounds not contained in the raw material oil are produced, and the hue of the product is saved. Bolt color will be worse than +30. This is the core of the problem that occurs when the sulfur content of the kerosene fraction is reduced to 10 ppm by mass or less using a conventional catalyst.
Since these compounds tend to increase when the reaction temperature is raised, the technique of the present invention that can keep the reaction temperature low is effective in avoiding deterioration in hue. In addition, the problem of a hue does not arise if the density | concentration of the specific 4-6 ring aromatic mentioned later is 30 mass microgram / kg or less, More preferably, it is 15 mass microgram / kg or less.
From the above knowledge, in the hydrodesulfurization catalyst of the present invention, the volume of pores having a diameter of 10 nm or more is set to 60% or more of the total pore volume in order to increase the diffusion rate of sulfur compounds. The pore distribution was measured from the desorption side by the BJH method (nitrogen). In addition, evacuation was performed at 200 ° C. for 3 hours as a pretreatment of the sample. As a measuring instrument, Cantachrome autosorb was used.

The hydrodesulfurization catalyst of the present invention preferably has one or more pore distribution peaks in the pore diameter range of 11 to 20 nm. It is preferable that the peak of the pore distribution is at a pore diameter of 11 nm or more, in the hydrodesulfurization reaction, which is not diffusion-controlled, and that the pore diameter is 20 nm or less, because there is no lack of activity due to a decrease in specific surface area. .
A higher specific surface area of the catalyst increases the dispersibility of the active metal and increases the number of active sites. From the above points, the specific surface area of the catalyst is preferably 50 m ² / g or more, more preferably 80 m ² / g or more, and particularly preferably 100 m ² / g or more. On the other hand, the higher the specific surface area, the smaller the pore diameter, which may not satisfy the above requirements regarding the pore diameter. From the above viewpoint, the specific surface area is preferably 200 m ² / g or less.

The hydrodesulfurization catalyst of the present invention is a catalyst having an active metal supported on a carrier.
Here, as the carrier, a refractory inorganic oxide is usually used and is not particularly limited as long as it has the above-described pore characteristics. Specific examples include alumina, silica, silica / alumina, magnesia, zirconia, zinc oxide, crystalline aluminosilicate, and clay mineral. These refractory inorganic oxides can be used alone or in admixture of two or more.
Of these refractory inorganic oxides, it is preferable to contain alumina in the support. As the alumina, γ-alumina, δ-alumina, η-alumina, θ-alumina, χ-alumina, etc. are preferably used. it can.

The method for producing alumina, which is a preferred embodiment as the carrier, is not particularly limited as long as it can produce a material having the pore structure. An example of the manufacturing method is shown below.
First, a specific alumina gel is prepared. This alumina gel is prepared by adding a base to an aqueous solution of the water-soluble acidic alumina salt, adding an acid to the aqueous solution of the water-soluble basic alumina salt, an aqueous solution of the water-soluble acidic alumina salt and the water-soluble basic alumina salt. The method of mixing the aqueous solution of this is mentioned. A commercially available alumina gel is added to this as needed, and an alumina support | carrier can be obtained by ageing | curing | ripening, drying, and baking. The shape of the carrier is not particularly limited, and examples thereof include a columnar shape, a trilobal shape, and a tetralobal shape.

Examples of the water-soluble acidic alumina salt include aluminum sulfate and aluminum nitrate. Examples of the water-soluble basic alumina salt include sodium aluminate.
In order to prepare the alumina so as to have a pore structure which is a feature of the present invention, the number of swings and the aging time are important factors in the aging. In addition, drying conditions of alumina gel, further extrusion conditions, particularly control of water content are important.
Specifically, the production of alumina gel is performed at a temperature of about 50 to 90 ° C. Moreover, about the aging method of the produced | generated gel, generally the operation (swing) which adds an acidic and alkaline solution alternately at the same temperature as the time of mixing is performed 3 times or more between pH 3.3-9.3, Preferably it is performed 5 times or more, more preferably 8 times or more. Further, a method of stirring at a temperature of 125 ° C. or higher at a pH of 10 or higher, preferably 130 ° C. or higher at a pH of 11 or higher (high temperature aging method) can be used. The stirring time here is preferably about 0.1 to 48 hours, and more preferably 0.2 to 24 hours. Furthermore, a high temperature aging method and a swing method may be used in combination.
In this step, the size of the primary particles of the alumina gel can be controlled by appropriately selecting the setting of the pH region, the temperature, and the number of times, and the pores composed of voids between the primary particles are made 11 nm or more. be able to.

Next, the temperature for drying the aged precipitate is preferably in the range of 80 to 200 ° C, more preferably in the range of 100 to 160 ° C. The firing temperature is preferably in the range of 400 to 700 ° C, more preferably in the range of 450 to 600 ° C.
As extrusion molding conditions, a good carrier free from cracks and cracks can be produced by appropriately controlling the amount of water and the temperature as appropriate.

  Moreover, the preparation method of the support | carrier which added the silica to the alumina can be manufactured by adjusting conditions suitably based on the method disclosed by Unexamined-Japanese-Patent No. 2001-162168.

  Molybdenum is suitable as the active metal in the hydrodesulfurization catalyst of the present invention. Molybdenum is preferably contained in the entire catalyst in an amount of 15% by mass or more based on the oxide. When the content is 15% by mass or more, sufficient desulfurization activity is obtained. From the above points, the content of molybdenum is more preferably 20% by mass or more based on oxides in the entire catalyst. As for the upper limit, from the viewpoint of balance with the content of the support and other metals described later, and in the case of a catalyst having a large pore diameter such as the catalyst of the present invention, the specific surface area of the support is relatively small, In view of the fact that the activity improving effect commensurate with the content of the active metal is not observed, the molybdenum content in the catalyst of the present invention is preferably 35% by mass or less, more preferably 30% by mass or less based on the oxide. Preferably there is.

In addition to molybdenum, it is preferable to contain a metal of Groups 8 to 10 of the periodic table. In particular, cobalt and / or nickel are preferred, and a three-component system of molybdenum, cobalt and nickel is also a preferred embodiment.
The content of the metals in groups 8 to 10 of the periodic table is preferably in the range of 1 to 10% by mass, more preferably in the range of 2 to 8% by mass, based on oxides, in the total catalyst. A suitable desulfurization activity is shown in this range.
In addition, it is preferable to add phosphorus as an active component of the catalyst. Phosphorus is preferably in the range of 1 to 10% by mass, more preferably in the range of 2 to 8% by mass, based on oxides (P ₂ O ₅ ) in the total catalyst. A suitable desulfurization activity is shown in this range.

As a method for loading these active metals, an impregnation method is preferred. That is, an impregnating solution in which the above active metal is dissolved is prepared and supported on a carrier. As the molybdenum compound used for the preparation of the impregnation liquid, molybdenum trioxide, ammonium paramolybdate and the like are suitable, and as the cobalt and / or nickel compound, nitrates, carbonates, basic carbonates, acetates of these metals, Organic acid salts and the like are preferable. As the phosphorus compound, various phosphoric acids such as orthophosphoric acid (orthophosphoric acid), metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, tetraphosphoric acid, polyphosphoric acid, phosphorus pentoxide, and the like are preferably used.
These compounds are dissolved to prepare a metal impregnating solution, and the amount of the impregnating solution is adjusted to be equal to the water absorption amount of the carrier. The impregnation liquid may be prepared for each metal or may be a mixture of a plurality of metals. However, from the viewpoint of efficient catalyst preparation, these metals are combined into one impregnation liquid. It is preferable to carry the mixed and dissolved material simultaneously.

  In addition, it is preferable to add a water-soluble organic compound to the metal impregnation liquid from the viewpoint of enhancing the activity. Specifically, it is preferable to add a water-soluble organic compound such as polyethylene glycol having a molecular weight of 90 to 10,000. The addition amount of the water-soluble organic compound is in the range of 1 to 20 parts by mass, more preferably 2 to 10 parts by mass with respect to 100 parts by mass of the carrier.

  It is preferable to dry at 80 to 200 ° C. after supporting the metal impregnation liquid on the carrier. If necessary, it can be fired at 200 to 700 ° C. thereafter. Drying and calcination are usually performed in air, and each is performed for 0.1 to 48 hours while circulating air as necessary, and more preferably in the range of 0.5 to 24 hours.

In the desulfurization reaction of kerosene, the desulfurization catalyst of the present invention may be charged 100% in the reactor, or may be a partial charge mixed with other catalysts. In the case of partial filling, the content is preferably 20% by mass or more of the total catalyst amount.
Further, the catalyst according to the present invention is preferably disposed on the rear stage side of the reactor. Specifically, the catalyst of the present invention is disposed in an area of 50% downstream of the reactor in an amount of 20% by mass or more of the total catalyst amount. It is preferred that Furthermore, it is preferable that 20% by mass or more of the total catalyst amount is disposed in the most downstream of the catalyst reactor of the present invention. The downstream side of the reactor is the most important part for desulfurizing the sulfur content to a target sulfur concentration (for example, 10 ppm by mass), and the catalyst of the present invention having no diffusion problem is disposed in this part. Is the most effective.

In the method for desulfurizing kerosene using the desulfurization catalyst of the present invention, the catalyst is preferably presulfurized in advance as a stabilization treatment. The sulfurizing agent used for presulfurization is not particularly limited, and in addition to hydrogen sulfide and carbon disulfide, organic sulfur compounds such as thiophene, dimethyl sulfide, dimethyl disulfide, dioctyl polysulfide, dialkylpentasulfide, dibutyl polysulfide, and mixtures thereof. Is mentioned. These organic sulfur compounds and mixtures thereof preferably have a decomposition temperature of 300 ° C. or lower, more preferably 250 ° C. or lower, particularly 220 ° C. or lower, and most preferably 200 ° C. or lower. When the decomposition temperature is 300 ° C. or less, there is an advantage that the sulfidation of the hydrogenation active metal component proceeds and the reduction does not easily proceed. Specifically, polysulfides such as dimethyl disulfide, dibutyl polysulfide, dioctyl polysulfide, and dialkyl pentasulfide are preferably used. In addition, the preliminary sulfidation using the preliminary sulfiding agent is usually performed by mixing the preliminary sulfiding agent with straight-run kerosene or light oil, which is the raw material oil, and passing it through the catalyst. Are preferably mixed and passed through the catalyst.
In addition, a method in which preliminary sulfidation is performed by passing raw material oil without using a preliminary sulfidizing agent is also suitable. In this case, since kerosene has a low sulfur content and a long sulfurization time, straight-run diesel oil may be used. The sulfur content in the raw oil used for preliminary sulfidation is preferably 0.2% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 1.0% by mass or more. Although there is no restriction | limiting in particular about the upper limit of sulfur content, If it is 2.0 mass% or more, a heavier fraction than light oil may be mixed, and it is not preferable. As the light oil fraction used here, a 90% distillation temperature based on ASTM D86 (JIS K2254) is preferably 380 ° C. or less, more preferably 370 ° C. or less, particularly 350 ° C. or less. preferable.

  As pre-sulfiding conditions, it is preferable to perform sulfiding treatment in the range of 120 to 230 ° C. until the degree of sulfidation reaches 50% or more. If the presulfiding temperature is 120 ° C. or higher and the hydrogenation active metal component is sufficiently sulfided, and if it is 230 ° C. or lower, hydrogen reduction of the hydrogenation active metal component does not occur. From the above viewpoint, the temperature range of preliminary sulfidation is more preferably in the range of 140 ° C to 220 ° C. Furthermore, it is preferable to complete the preliminary sulfidation in the range of 300 ± 50 ° C.

The degree of sulfidation is preferably 70% or more, more preferably 80% or more, and particularly preferably 90% or more.
Here, the degree of sulfidation refers to the mass of sulfur necessary for the hydrogenation active metal to be sulfided to a stable sulfide, A is the total sulfur supply amount, and B is the form of hydrogen sulfide (H ₂ S) in the off-gas. When the cumulative mass of sulfur distilled in step C is C and the cumulative mass of sulfur distilled in the liquid is D, it is defined as 100 × (B−C−D) / A. It should be noted that the hydrogenation active metal is sulfided into a stable sulfide when the metal element is M, and in the periodic table group 6 metal up to the MS ₂ state, the periodic table group 8 to 10 metal In, it means that it was sulfided to the MS state.

About the conditions of hydrodesulfurization of kerosene in this invention, it is preferable that reaction temperature is the range of 200-360 degreeC, Furthermore, 250-340 degreeC, Especially the range of 260-325 degreeC is preferable. When the reaction temperature is 200 ° C. or higher, the desulfurization reaction proceeds sufficiently. On the other hand, when the reaction temperature is 360 ° C. or lower, the amount of color-causing substances produced is small and the product is not colored.
The hydrogen partial pressure is preferably in the range of 2 to 15 MPa. When the hydrogen partial pressure is within this range, the generation of the color-causing substance is sufficiently suppressed. From the above points, a range of 3 to 12 MPa, particularly 3.5 to 10 MPa is preferable. The liquid hourly space velocity (LHSV), preferably in the range of 2~15h ^-1, more range 3~12h ^-1, particularly preferably in the range of 5~10h ^-1. When the liquid hourly space velocity (LHSV) is 2 or more, the production time of the colored substance due to the residence time (1 / LHSV) being too long is not increased, and the liquid hourly space velocity (LHSV) is 15 or less. A sufficient desulfurization rate can be obtained.
About hydrogen / oil ratio, the range of 50-500 Nm < ³ > / kL is preferable, Furthermore, the range of 70-300 Nm < ³ > / kL, especially 70-200 Nm < ³ > / kL is preferable.

The desulfurization catalyst of the present invention is particularly excellent as a desulfurization catalyst for kerosene. The kerosene referred to in the present invention is a distillation based on ASTM D86 having a 5% distillation temperature of 100 ° C. or higher and a 95% distillation temperature of 300%. The one with a 95% distillation temperature is 275 ° C or less, more preferably the one with a 95% distillation temperature is 265 ° C or less. Here, the kerosene includes not only a direct distillation system but also a cracked kerosene fraction. Note that cracking kerosene means, for example, fluid catalytic cracking equipment, heavy gas oil hydrodesulfurization equipment, vacuum gas oil hydrodesulfurization equipment, vacuum gas oil hydrocracking equipment, atmospheric pressure residual oil hydrodesulfurization equipment, atmospheric pressure residue. Kerosene obtained from oil hydrocracking equipment, vacuum residue hydrodesulfurization equipment, vacuum residue hydrocracking equipment, various coker equipment, and the like.
In addition, the kerosene desulfurized using the desulfurization catalyst of the present invention can easily reduce the sulfur content to 10 ppm by mass or less, and further to 1 ppm by mass or less. The kerosene desulfurized using the desulfurization catalyst of the present invention has good properties as kerosene, that is, Saebold color +30 or more.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Evaluation Method (1) Physical Properties of Catalyst (1-1) Pore Volume, Pore Diameter, Pore Distribution, Specific Surface Area Measured by a nitrogen adsorption method using a pore distribution measuring device (“Autosorb” manufactured by Cantachrome) did.
(1-2) Metal content The reagent is baked in an electric furnace at 500 ° C. for 4 hours to form a metal oxide (NiO, CoO, MoO ₃ , WO ₃ etc.), and the content as a metal oxide Asked. From the obtained metal oxide content, it is assumed that the metal oxide contained in the metal impregnating solution is 100% supported on the refractory inorganic oxide carrier, and the amount of each reagent so that the target metal content is obtained. It was determined. The supported amount of the metal oxide was confirmed by using a commercially available analytical instrument such as XRF (fluorescent X-ray method) and ICP (plasma emission method) for the catalyst body. These analytical instruments were calibrated with calibration curves obtained using standard reagents of known concentrations.
(2) Properties of desulfurized kerosene (2-1) Sulfur content in kerosene; measured in accordance with JIS K2541-2 and K2541-6.
(2-2) Saebold color: Based on the stimulus value conversion method of JIS K2580, it was measured to one decimal place. Moreover, +30 or more was calculated | required by extrapolation.
(2-3) Density (15 ° C.): Measured according to JIS K2249.
(2-4) Kinematic viscosity (30 ° C.): Measured according to JIS K2283.
(2-5) Smoke point; measured in accordance with JIS K2537.
(2-6) Flash point: Measured according to JIS K2265.
(2-7) Copper plate corrosion; measured according to JIS K2513.
(2-8) Nitrogen content: measured in accordance with JIS K2609.
(2-9) Peroxide value: measured in accordance with JIS K2276-20.
(2-10) Doctor test: Measured according to JIS K2276-11.
(3) Composition in kerosene; in accordance with JPI-5S-49-97, saturated hydrocarbons, unsaturated hydrocarbons, monocyclic aromatic compounds, bicyclic aromatic compounds in raw kerosene and desulfurized kerosene, and 3 The content of aromatic compounds above the ring was measured.
The 4- to 6-ring aromatic compound was quantified by the following method consisting of two steps.
First, kerosene was concentrated according to ASTM column chromatography (D-2549-02) so that the colored component was only the resin component (polar component). Next, the resin was analyzed with a high-resolution mass spectrometer equipped with a gas chromatograph (“JMS-700” manufactured by JEOL Ltd.).
In the quantification method, a calibration curve was prepared for each reagent of a commercially available 4- to 6-ring aromatic compound that was colored, and the concentration of each colored compound in the resin component, that is, in the kerosene sample was determined. The observed ion was an ion (parent ion) of the molecular weight of the aromatic compound of interest. An Agilent 6890 apparatus was used as the gas chromatograph, DB-5MS (5% phenylmethylsilicon) was used as the column, and an inner diameter of 0.25 mm and a length of 30 m were used. The oven temperature was raised from 80 ° C. to 325 ° C. at 5 ° C./min and held at that temperature for 10 minutes. The inlet temperature was 300 ° C. Helium was used as the carrier gas, and the flow rate was 1.0 mL / min. As a sample injection method, splitless injection was used, and the injection amount was 1.0 μL. The measurement conditions for mass spectrometry were an ion voltage for electron impact ionization of 42 eV and an ionization current of 400 μA. The resolution was 10,000 (10% trough), and the measurement was performed by the rock mass method.
The measured 4- to 6-ring aromatic compounds are pyrene, benzo (a) anthracene, chrysene as tetracyclic aromatic compounds, benzo (b) fluoranthene, benzo (k) fluoranthene, benzo (a ) Pyrene, dibenzo (a, h) anthracene, 6-ring aromatic compounds, indeno (1,2,3-cd) pyrene, benzo (ghi) perylene, and 4-6 ring aromatic compounds are those of these compounds Expressed as the total concentration.
(4) Reaction evaluation: 100 cm ³ of the catalyst obtained in each Example and Comparative Example was charged into a continuous fixed bed reactor, treated under the following presulfurization conditions, and then switched to the following raw kerosene for reaction. Evaluation was performed.
Presulfurization conditions: DMDS (dimethyl disulfide) was added to straight-run kerosene having a sulfur content of 1100 mass ppm, which will be described later, to prepare a presulfurized oil having a sulfur content of 2.0 mass%. Using this preliminary sulfurized oil, oil passage was started under the conditions of a hydrogen partial pressure of 3.92 MPa · G, a hydrogen / oil ratio of 100 Nm ³ / kL, a temperature of 100 ° C., and an LHSV (liquid space velocity) of 6.0 h ^−1. The temperature was raised to 170 ° C. at a temperature rate of 20 ° C./h, held at this temperature for 3 hours, heated to 220 ° C. at the same temperature rise rate, held at this temperature for 4 hours, and further 290 at the same temperature rise rate. Pre-sulfurization was performed by raising the temperature to 0 ° C. and holding at that temperature for 9 hours.
As the raw material oil, straight-run kerosene having the following properties was used and reacted under the following reaction conditions. When the reaction temperature was changed, the sulfur content (mass ppm), kerosene color, etc. of the kerosene obtained were evaluated by the above methods. The evaluation results are shown in Table 1.
Raw material oil properties: sulfur content; 1100 mass ppm, Saebold color; +33.6, density; 0.7955 g / cm ³ , kinematic viscosity (30 ° C.); 1.414 mm ² / s, saturated hydrocarbon; 80.1% by volume 0% by volume, 1 ring aromatic; 17.6% by volume, 2 ring aromatics; 2.3% by volume, 3 or more aromatics; 0% by volume (4-6 ring aromatics; 10 mass ppb or less), smoke point: 24 mm, flash point: 42 ° C., and nitrogen content: 2 mass ppm
Reaction conditions: LHSV; 6.0 h ⁻¹ , hydrogen partial pressure; 3.92 MPa · G (40 kg / cm ² G), hydrogen / oil ratio; 100 Nm ³ / kL

Example 1
Aluminum nitrate (500 g) was dissolved in 1 L of deionized water to obtain an aluminum solution (a). Next, 35 g of sodium hydroxide was dissolved in 1 L of deionized water, and 99 g of sodium aluminate was further added to obtain a uniform aluminum solution (b).
Next, 2.5 L of deionized water was heated to 70 ° C., and the aluminum solution (a) was added with stirring until the pH reached 3.5. Next, the aluminum solution (b) was added until the pH reached 9.0 and aged with stirring for 10 minutes. Thus, the operation of changing the pH in the range of 3.5 to 9.0 was repeated 8 times. Then, when the obtained gel was filtered and washed to recover the alumina gel, its mass was 840 g. The amount of water in the alumina gel was adjusted by stirring while heating to 80 ° C., and extruded into a cylindrical mold. Then, it was dried at 120 ° C. for 24 hours and further calcined at 500 ° C. for 4 hours to obtain an alumina carrier.

Next, 300 g of molybdenum trioxide (MoO ₃ content: 100%), 103 g of basic nickel carbonate, 65 g of normal phosphoric acid (85.2 mass% of normal phosphoric acid) are dissolved in ion-exchanged water at 80 ° C., An aqueous solution (metal impregnating solution) having a total amount of 427 mL was prepared. To the metal impregnating solution, 6 parts by mass of triethylene glycol was added to 100 parts by mass of the alumina support, and the alumina support was impregnated. After impregnation, the catalyst body was dried at 120 ° C. for 4 hours.
The volume of pores having a diameter of 10 nm or more in the catalyst body was 81% of the total pore volume, and the peak top of the pore distribution was at the position of 14 nm. The specific surface area of the catalyst is 112 m ² / g, and the molybdenum, nickel, and phosphorus contents are 27% by mass, 5.4% by mass, and oxide content (MoO ₃ , NiO, P ₂ O ₅ ), respectively. It was 3.6 mass%.
The results of the above-described reaction evaluation for the catalyst are shown in Table 1.

Comparative Example 1
32.1 g of ammonium paramolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O)], 27.1 g of cobalt nitrate [Co (NO ₃ ) ₃ ], polyethylene glycol 400 [HO— (CH ₂ CH ₂ O) ) N-H: molecular weight of about 400] 10.0 g and malic acid [HOCOCH ₂ CH (OH) COOH: molecular weight of 134] 16.0 g were dissolved in ion-exchanged water to prepare an aqueous solution (impregnation solution) having a total amount of 86 mL. .
This impregnating liquid was supported on 200 g of a cylindrical alumina carrier (particle diameter: 2 mm) having a specific surface area of 320 m ² / g by a vacuum impregnation method. The support was dried at 120 ° C. for 3 hours and then calcined at 550 ° C. for 3.0 hours in an air stream to obtain a catalyst body.
The volume of pores having a diameter of 10 nm or more in the catalyst body was 2% of the total pore volume, and the peak top of the pore distribution was at a position of 7 nm. The specific surface area of the catalyst was 246 m ² / g, and the molybdenum and cobalt contents were 18% by mass and 5% by mass, respectively, in terms of oxide (MoO ₃ , CoO).
The results of the above-described reaction evaluation for the catalyst are shown in Table 1.

Comparative Example 2
The alumina support used in Comparative Example 1 was impregnated with the metal impregnating solution prepared in Example 1 so that the same metal loading as in Example 1 was obtained. After impregnation, the catalyst body was dried at 120 ° C. for 4 hours. The volume of pores having a diameter of 10 nm or more in the catalyst body was 1% of the total pore volume, and the peak top of the pore distribution was at a position of about 6.5 nm. The specific surface area of the catalyst was 185 m ² / g.

  The catalyst prepared in Example 1 is highly active at low temperatures and can be as low as about 20 ° C. to obtain an equivalent desulfurization rate compared to the catalysts prepared in Comparative Examples 1 and 2. . In addition, when desulfurization is performed at the same temperature, it can be seen that the desulfurization rate is high and the Saybolt color is also good. In Example 1, when the reaction temperature is increased to 330 ° C., the Saebold color is remarkably deteriorated. This is because 90 mass ppb of the 4-6 ring aromatic compound, which is the color causative substance, is generated. Increasing the reaction temperature more than necessary increases the color causative substance and leads to deterioration of the Saebold color. It is shown that.

  By using the hydrodesulfurization catalyst of the present invention, a high desulfurization rate can be achieved, and kerosene having a sulfur content of 10 mass ppm or less can be produced efficiently. In addition, kerosene produced with the desulfurization catalyst is not colored and has good product properties.

Claims (2)

The catalyst is packed in an area of 50% downstream of the reactor in an area of 50% or more of the total catalyst amount, the reaction temperature is 200 to 325 ° C. , the hydrogen partial pressure is 2 to 15 MPa, and the liquid space velocity is 2 to 15 h ^−1. , A hydrodesulfurization method for obtaining kerosene having a sulfur content of 10 ppm by mass or less and a Saebold color +30 or more ,
The catalyst carries 15 mass% or more of molybdenum as an active metal on an alumina support, 1 to 10 mass% of nickel as an oxide, and 1 to 10 mass% of phosphorus as an active component based on an oxide. The catalyst does not contain cobalt, and the volume of pores having a diameter of 10 nm or more is 60% or more of the total pore volume, and has one or more pore distribution peaks in the pore diameter range of 11 to 20 nm. A kerosene fraction having a specific surface area of 100 to 200 m ² / g, a reaction temperature of 200 to 325 ° C., a sulfur content of 10 mass ppm or less, and kerosene having a Saybolt color of +30 or more. hydrodesulfurization catalyst (excluding 18 wt% molybdenum on an oxide basis, 4 wt% of nickel on an oxide basis, and phosphorus catalyst containing 6% by weight on an oxide basis as active ingredient) is this Hydrodesulfurization method of kerosene fraction, wherein. The hydrodesulfurization method for a kerosene fraction according to claim 1, wherein the 4-6 ring aromatic compound of kerosene is adjusted to 15 mass µg / kg or less.