JP2011200797A - Method of selecting regeneration condition for hydrotreating catalyst and method of producing regenerated hydrotreating catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of selecting regeneration conditions for a hydrotreating catalyst which enables production of a regenerated hydrotreating catalyst having a stably high activity from a used hydrotreating catalyst.SOLUTION: A hydrotreating catalyst which consists of cobalt supported by an inorganic support containing an aluminum oxide and is to be used in hydrotreating is subjected to an XAFS analysis to obtain a radial distribution curve from an EXAFS spectrum of the CoK absorption edge, and an intensity Iof the peak assigned to the Co-O bond in the radial distribution curve. Then, a catalyst after use in hydrotreating is regenerated under specified regeneration conditions, and the catalyst after the regeneration is subjected to an XAFS analysis to obtain a radial distribution curve from an EXAFS spectrum of the CoK absorption edge, and an intensity I of the peak assigned to the Co-O bond in the radial distribution curve. Based on a predetermined correlation of I/Iwith the activity of the catalyst, the quality of the regeneration conditions is determined.

Description

  The present invention relates to a method for selecting a regeneration condition for a hydrotreating catalyst and a method for producing a regenerated hydrotreating catalyst.

  Crude oil contains sulfur-containing compounds, nitrogen-containing compounds, oxygen-containing compounds and the like as impurities, and these impurities are also contained in each distillate petroleum fraction obtained by fractionating crude oil. The content of the impurities in these distillate petroleum fractions is reduced by a process called hydrotreatment in which the impurities are brought into contact with a catalyst having hydrogenation activity in the presence of hydrogen. In particular, desulfurization for reducing the content of sulfur-containing compounds is well known. Recently, from the viewpoint of reducing environmental impact, regulations on the content of impurities, including sulfur-containing compounds in petroleum products, and demands for reduction have become more stringent, and there are many so-called “sulfur-free” petroleum products. Has been produced.

  The hydrotreating catalyst used for the hydrotreating of the distillate petroleum fraction is exchanged because its activity decreases due to the deposition of coke and sulfur when used for a certain period of time. In particular, the above-mentioned “sulfur-free” has been demanded, and high hydrotreating capacity is demanded in hydrotreating equipment for fractions such as kerosene, light oil and vacuum gas oil. As a result, the frequency of catalyst replacement increases, resulting in an increase in catalyst cost and an increase in the amount of catalyst discarded.

  As a countermeasure, a part of the regenerated catalyst (regenerated hydrotreating catalyst) obtained by regenerating a spent hydrotreating catalyst is used in these facilities (for example, see Patent Documents 1 and 2). .)

JP 52-68890 A JP-A-5-123586

  In using the regenerated hydrotreating catalyst, if the activity of the hydrotreating catalyst can be maintained even if the hydrotreating and regenerating treatment are repeated a plurality of times, the regenerated hydrotreating catalyst (hereinafter referred to as “ The advantage of using “regenerated hydrotreating catalyst” or simply “regenerated catalyst”) is even greater.

  Here, in the conventional regeneration treatment, the main cause of the decrease in activity that occurs during the use of the catalyst for hydrotreating is the deposition of coke or sulfur. Therefore, the regeneration treatment condition is whether or not these deposits can be removed. In general, the regeneration processing conditions are selected from the viewpoint. For example, in conventional regeneration processing, it has been considered that the processing temperature should be as high as possible.

  However, according to the study of the present inventor, apart from the problem of removing the deposited coke or sulfur, the regeneration process itself has a structure of active metal supported on the catalyst (coordination form of active metal and oxygen atoms, etc.). It has been found that the catalytic activity may be reduced by, for example, changing.

  For this reason, the catalyst activity after regeneration differs depending on the use history before regeneration of the catalyst, the regeneration treatment method, etc., and the regeneration catalyst, particularly the regeneration catalyst after regeneration a plurality of times, does not always have a stable and sufficient activity. Further, it may be necessary to select different regeneration treatment conditions depending on the history of the used catalyst. Then, when the regenerated catalyst is filled in the hydrotreating facility and the hydrotreating operation is started and it is found that its activity is low, it is necessary to reduce the processing speed of the raw oil, which is a big problem. Become.

  For the reasons described above, the actual situation is that the regenerated catalyst is not sufficiently employed in the hydrotreating equipment. Therefore, there is a strong demand to supply a regenerated catalyst that stably suppresses the decrease in activity during the regeneration of the hydrotreating catalyst and has a high activity.

  The present invention has been made in view of such circumstances, and an object thereof is to make it possible to produce a regenerated hydrotreating catalyst having high activity stably from a used hydrotreating catalyst. Another object of the present invention is to provide a method for selecting a regeneration treatment condition for a hydrotreating catalyst and a method for producing a regeneration hydrotreating catalyst.

In order to solve the above-described problems, the present invention provides a method for selecting a regeneration condition for a hydrotreating catalyst described in (1) below, and a regenerated hydrotreating catalyst described in (2) and (3) below. A manufacturing method is provided.
(1) When regenerating a hydrotreating catalyst for treating a distillate petroleum fraction, a method for selecting regeneration treatment conditions,
An inorganic carrier containing aluminum oxide and a catalyst for hydrotreating containing cobalt supported on the inorganic carrier and before being used for hydrotreating are subjected to X-ray absorption fine structure analysis to obtain Co K absorption. A first step of obtaining a radial distribution curve from the broad X-ray absorption fine structure spectrum at the end, and obtaining an intensity I _{0 of} a peak attributed to a Co—O bond in the radial distribution curve;
The hydrotreating catalyst after the hydrotreating is regenerated under predetermined conditions, the regenerated catalyst is subjected to X-ray absorption fine structure analysis, and from the wide X-ray absorption fine structure spectrum of the Co K absorption edge. A second step of obtaining a radial distribution curve and obtaining an intensity I of a peak attributed to a Co-O bond in the radial distribution curve;
The ratio I / I ₀ of I obtained in the second step with respect to I ₀ obtained in the first step is obtained, and based on the correlation between the peak intensity ratio I / I ₀ obtained in advance and the catalyst activity A third step of determining whether or not the conditions of the regeneration process in the second step are good,
A method for selecting a regeneration treatment condition for a hydrotreating catalyst.
(2) An inorganic carrier containing an aluminum oxide and a catalyst for hydrotreatment containing cobalt supported on the inorganic carrier, and the catalyst after being used for hydrotreatment for treating a distillate petroleum fraction A method for producing a regenerated hydrotreating catalyst, comprising a step of regenerating the catalyst under the conditions selected by the method according to (1).
(3) The method according to (2), wherein the selected condition satisfies the condition represented by the following formula (1).
1.22 ≦ I / I ₀ ≦ 1.35 (1)
[In the formula (1), I ₀ represents the intensity of a peak attributed to a Co—O bond in the radial distribution curve of the hydrotreating catalyst before being used for hydrotreating, and I represents hydrogen The intensity | strength of the peak which belongs to the Co-O bond in the radial distribution curve of the said catalyst for hydrogenation treatment after passing through a hydrogenation process and a regeneration process is shown. ]

  ADVANTAGE OF THE INVENTION According to this invention, the selection method of the regeneration conditions of the hydrotreating catalyst which makes it possible to manufacture the regenerated hydrotreating catalyst which has a stable high activity from the used hydrotreating catalyst, and A method for producing a regenerated hydrotreating catalyst is provided.

It is a graph which shows an example of the EXAFS (X-ray Absorption Fine Structure) spectrum of a CoK absorption edge. It is a graph which shows an example of a radial distribution curve. Obtained in Examples 1 to 5 and Comparative Examples 2 and 3, is a graph showing the correlation between the peak intensity ratio I / I ₀ and specific activity. Obtained in Example 6-8 and Comparative Example 4 is a graph showing the correlation between the peak intensity ratio I / I ₀ and specific activity.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

(Hydroprocessing catalyst)
The hydrotreating catalyst in the present embodiment contains an inorganic carrier containing aluminum oxide and cobalt supported on the inorganic carrier.

  Preferred examples of the inorganic carrier containing aluminum oxide include alumina, alumina-silica, alumina-boria, alumina-titania, alumina-zirconia, alumina-magnesia, alumina-silica-zirconia, alumina-silica-titania, or various zeolites. And a carrier obtained by adding a porous inorganic compound such as various clay minerals such as ceviolite and montmorillonite to alumina, among which alumina is particularly preferable.

  In the hydrotreating catalyst according to the present embodiment, the supported amount of cobalt is preferably 0.5 to 10% by mass, more preferably 1 to 7% by mass as cobalt oxide.

  Moreover, on the said inorganic support | carrier, 1 type, or 2 or more types of active metals selected from the periodic table group 8-10 metal and molybdenum other than cobalt may further be carry | supported. As Group 8-10 metals of the periodic table other than cobalt, iron and nickel are preferable, and nickel is more preferable. Specifically, cobalt-molybdenum, cobalt-molybdenum-nickel, or the like is preferably used as the active metal combination in the present embodiment. Here, the periodic table is a long-period type periodic table defined by the International Union of Pure and Applied Chemistry (IUPAC). The supported amount of the active metal other than cobalt is preferably 0.5 to 40% by mass, more preferably 1 to 30% by mass as an oxide of the active metal.

  As a preferred embodiment of the above-mentioned hydrotreating catalyst which is unused (unused catalyst), an inorganic carrier containing aluminum oxide is used in an amount of 1 to 7 with cobalt as an oxide based on the total mass of the catalyst. Examples thereof include catalysts obtained by supporting 10% by mass and 10% by mass of molybdenum as an oxide.

  The precursor of the active metal species used when cobalt and other active metals used as necessary are supported on the inorganic carrier is not limited, but inorganic salts of each metal, organometallic compounds, etc. are used, and water-soluble Inorganic salts are preferably used. In the supporting step, it is preferable to support using a solution of these active metal precursors, preferably an aqueous solution. As the supporting operation, for example, a known method such as an immersion method, an impregnation method, a coprecipitation method, or the like is preferably employed.

  The carrier on which the active metal precursor is supported is preferably dried and then calcined in the presence of oxygen, and the active metal species is once converted to an oxide. Further, before the hydrotreating of the distillate petroleum fraction, the active metal is preferably converted into a sulfide by a sulfiding treatment called presulfiding.

(Hydrogenation process)
In the hydrotreating process of the distillate petroleum fraction, before the hydrotreating reaction, the catalyst charged in the facility is converted into a metal sulfide by treating the catalyst with a sulfur compound called presulfurization. It is preferable.

Although it does not specifically limit as conditions for preliminary sulfidation, a sulfur compound is added to the feedstock used for the hydrogenation process of the distillate petroleum fraction, this is temperature 200-380 degreeC, LHSV 1-2h- ¹ , Pressure is hydrogen. It is preferable to continuously contact the regenerated hydrotreating catalyst under the same conditions as in the hydrotreating operation and for a treating time of 48 hours or longer. Although it does not limit as a sulfur compound added to the said raw material oil, Dimethyl disulfide (DMDS), hydrogen sulfide, etc. are preferable, and it is preferable to add these about 1 mass% with respect to the mass of a raw material oil with respect to raw material oil.

  The operating conditions in the hydrotreating process of the distillate petroleum fraction are not particularly limited, and a small amount of a sulfur compound such as DMDS may be added to the feedstock for the purpose of maintaining a state where the active metal species of the catalyst is sulfide. Although it is good, it is usually preferable not to add a sulfur compound because it is possible to maintain a sulfide state by the sulfur compound already contained in the feedstock.

  The hydrogen partial pressure at the reactor inlet in the hydrotreating step is preferably 3 to 13 MPa, more preferably 3.5 to 12 MPa, and particularly preferably 4 to 11 MPa. When the hydrogen partial pressure is less than 3 MPa, coke formation on the catalyst becomes intense and the catalyst life tends to be shortened. On the other hand, when the hydrogen partial pressure exceeds 13 MPa, there is a concern that the construction cost of the reactor, peripheral equipment, and the like will increase and the economy will be lost.

LHSV in the hydrogenation process is preferably 0.05～5H ^-1, more preferably 0.1～4.5H ^-1, particularly preferably may be in the range of 0.2~4h ^-1. When LHSV is less than 0.05 h ⁻¹ , there is a concern that the construction cost of the reactor becomes excessive and the economic efficiency is lost. On the other hand, when LHSV exceeds 5h- ¹ , there is a concern that the hydrogenation treatment of the raw material oil is not sufficiently achieved.

  The hydrogenation reaction temperature in the hydrotreating step is preferably 200 ° C to 410 ° C, more preferably 220 ° C to 400 ° C, and particularly preferably 250 ° C to 395 ° C. When the reaction temperature is lower than 200 ° C., the hydrogenation treatment of the raw material oil tends not to be sufficiently achieved. On the other hand, when the reaction temperature exceeds 410 ° C., the generation of a gas component as a by-product increases, which is not desirable because the yield of the target refined oil decreases.

  The hydrogen / oil ratio in the hydrotreating step is preferably 100 to 8000 SCF / BBL, more preferably 120 to 7000 SCF / BBL, and particularly preferably 150 to 6000 SCF / BBL. When the hydrogen / oil ratio is less than 100 SCF / BBL, coke formation on the catalyst proceeds at the reactor outlet, and the catalyst life tends to be shortened. On the other hand, when the hydrogen / oil ratio exceeds 8000 SCF / BBL, there is a concern that the construction cost of the recycle compressor becomes excessive and the economic efficiency is lost.

  The reaction type in the hydrotreating step is not particularly limited, but usually, it can be selected from various processes such as a fixed bed and a moving bed, but a fixed bed is preferable. The reactor is preferably tower-shaped.

As the feedstock to be subjected to the hydrotreating of the distillate petroleum fraction, the distillation temperature by distillation test is preferably 130 to 700 ° C, more preferably 140 to 680 ° C, particularly preferably 150 to 660 ° C. Things are used. When a feed oil having a distillation temperature lower than 130 ° C. is used, the hydrotreating reaction becomes a reaction in the gas phase, and the above-mentioned catalyst tends not to exhibit sufficient performance. On the other hand, when a feedstock having a distillation temperature exceeding 700 ° C. is used, the content of poisonous substances with respect to the catalyst such as heavy metals contained in the feedstock is increased, and the life of the catalyst is greatly reduced. Other properties of the distillate petroleum fraction used as the feedstock are not particularly limited, but typical properties include a density at 15 ° C. of 0.8200 to 0.9700 g / cm ³ and a sulfur content of 1.0 to It is 4.0 mass%.

  The sulfur content means a sulfur content measured in accordance with “Radiation Excitation Method” of “Crude Oil and Petroleum Products—Sulfur Content Test Method” defined in JIS K2541-1992. Further, the distillation test means a test conducted in accordance with “Petroleum product-distillation test method” “depressurization method distillation test method” or “gas chromatographic method distillation test method” defined in JIS K 2254. It means what is performed in accordance with the density at 15 ° C. and “vibration density test method” of “crude oil and petroleum products—density test method and density / mass / capacity conversion table” defined in JIS K2249.

(Selection method of regeneration processing conditions)
The selection method of the regeneration processing conditions according to this embodiment includes the following steps.
Step (1): X-ray absorption fine structure analysis of an inorganic carrier containing aluminum oxide and a catalyst for hydrotreatment containing cobalt supported on the inorganic carrier before being used for hydrotreatment Then, a radial distribution curve is obtained from the wide-area X-ray absorption fine structure spectrum at the Co K absorption edge, and the peak intensity I ₀ attributed to the Co—O bond in the radial distribution curve is obtained.
Step (2): The hydrotreating catalyst after the hydrotreating is regenerated under predetermined conditions, the regenerated catalyst is subjected to X-ray absorption fine structure analysis, and the broad X-ray at the Co K absorption edge. A radial distribution curve is obtained from the absorption fine structure spectrum, and a peak intensity I attributed to the Co—O bond in the radial distribution curve is obtained.
Step (3): The ratio I / I ₀ of I obtained in Step (2) to I ₀ obtained in Step (1) is determined, and the ratio I / I _{0 of the} peak intensity obtained in advance and the catalytic activity are obtained. Whether or not the conditions of the reproduction process in the second step are good is determined based on the correlation with the above.

  The X-AFS (X-ray Absorption Fine Structure) analysis in the steps (1) and (2) is performed by changing the energy of the X-rays included in the emitted light generated by the electron accelerator or the X-rays corresponding thereto. This is a method of irradiating a substance and analyzing the structure of the substance by an absorption spectrum (XAFS spectrum) in which the X-ray absorption rate of the substance is plotted against the X-ray energy. The EXAFS spectrum is a spectrum in a region on the higher energy side than the region (absorption edge, CoK absorption edge in the present embodiment) in which the X-ray absorption rate rapidly changes with respect to the irradiation X-ray energy. is there. A radial distribution curve shown in FIG. 2 can be obtained by Fourier transforming the EXAFS spectrum.

Information on the structure around the measurement target atom can be obtained from the radial distribution curve obtained in this way. In the present embodiment, focusing on a peak (usually a peak having an interatomic distance of 0.16 nm ± 0.02 nm) attributed to the Co—O bond in the radial distribution function, the steps (1), (2 ), Peak intensities I ₀ and I are obtained.

The XAFS analysis in the present invention is performed by the following method (the same applies to the examples described later).
X-ray source: Continuous X-ray spectroscopic crystal: Si (111)
Beam size: 1mm x 2mm
Detector: Ionization chamber Measurement atmosphere: Air Dwell time: 1 sec
Measurement range: Co K absorption edge (7200-8800 eV)
Data analysis (Fourier transform) program: REX2000 (manufactured by Rigaku)

  For details on data analysis, such as taking a baseline when extracting EXAFS spectra, see "X-ray absorption spectroscopy-XAFS and its applications-Toshiaki Ota, published by IPC (2002), pages 57-61. Can be performed using the XAFS analysis integration software REX2000 (Rigaku). This technique was also adopted in the examples described later.

In step (3), the ratio I / I ₀ of I obtained in step (2) to I ₀ obtained in step (1) is determined, and the peak intensity ratio I / I ₀ obtained in advance and the catalyst are obtained. Based on the correlation with the activity, the quality of the condition of the regeneration process in the second step is determined.

In this embodiment, the correlation between the peak intensity ratio I / I ₀ used in the step (3) and the catalyst activity is the same as that in the step (2) for a plurality of regenerated hydrotreating catalysts regenerated under different regeneration conditions. On the other hand, the catalytic activity of these regenerated hydrotreating catalysts can be evaluated in advance. Examples of the regeneration processing conditions include processing temperature, processing time, processing atmosphere, and the like. Moreover, desulfurization activity etc. are mentioned as catalyst activity to evaluate.

For example, the above step (1) is performed on the unused catalyst. In addition, a plurality of regenerated hydrotreating catalysts are obtained by changing the treatment temperature of the used hydrotreating catalyst and performing a regenerating process in which other regeneration conditions are fixed. The above step (2) is performed for each catalyst. On the other hand, the desulfurization activity is evaluated for each of the unused catalyst and the regenerated hydrotreating catalyst, and the correlation between the obtained I / I ₀ and the desulfurization activity is obtained in advance. Since the activity of the unused catalyst (new catalyst) differs depending on the manufacturer, production unit, etc., the activity of the regenerated hydrotreating catalyst obtained by regenerating after using the hydrotreating catalyst is considerable. It is considered appropriate to evaluate the relative activity based on the activity standard of the unused catalyst. Therefore, the activity of the regenerated hydrotreating catalyst is evaluated based on the specific activity defined by the following equation.
Specific activity = desulfurization rate constant of regenerated hydrotreating catalyst / desulfurization rate constant of unused hydrotreating catalyst

Based on the correlation between the peak intensity ratio I / I ₀ thus obtained and the catalyst activity, by determining whether the conditions of the regeneration treatment in the second step are good or not, from the used hydrotreating catalyst, Regeneration conditions for producing a regenerated hydrotreating catalyst having high activity stably can be accurately selected.

(Method for producing regenerated hydrotreating catalyst)
The method for producing a regenerated hydrogenation catalyst according to the present embodiment includes an inorganic carrier containing aluminum oxide and a cobalt hydrotreating catalyst containing cobalt supported on the inorganic carrier under the regeneration treatment conditions selected by the above method. The method comprises a step of regenerating the catalyst after it has been used for hydroprocessing to treat a distillate petroleum fraction.

  Although the equipment used for the regeneration treatment process is not particularly limited, it is preferably carried out in equipment different from the hydrotreating equipment for the distillate petroleum fraction. That is, instead of performing the regeneration process with the catalyst in the reactor of the hydrotreating equipment of the distillate petroleum fraction, the catalyst is extracted from the reactor, and the extracted catalyst is used for the regeneration process. It is preferable to move to an equipment and perform a regeneration process using the equipment.

  The form for regenerating the used catalyst is not limited, but the process of removing the finely divided catalyst from the used catalyst, and in some cases, the filler other than the catalyst by sieving, removing the oil adhering to the used catalyst It is preferable that the step is constituted in this order from the step of performing (deoiling step), the step of removing coke deposited on the used catalyst, the sulfur content, etc. (regeneration step).

  Among these, in the deoiling step, a method of volatilizing the oil by heating the used catalyst to a temperature of about 200 to 400 ° C. in an atmosphere where oxygen is not substantially present, for example, a nitrogen atmosphere is preferably employed. The The deoiling step may be performed by a method of washing oil with light hydrocarbons or a method of removing oil by steaming.

As the regeneration process conditions in the regeneration process, those determined as “good” in the above-described regeneration process condition selection method are adopted. For example, it is preferable that the selected conditions satisfy the condition represented by the following formula (1) because sufficient catalyst activity can be imparted to the hydrotreating catalyst after the regeneration treatment.
1.22 ≦ I / I ₀ ≦ 1.35 (1)
[In the formula (1), I ₀ represents the intensity of a peak attributed to a Co—O bond in the radial distribution curve of the hydrotreating catalyst before being used for hydrotreating, and I represents hydrogen The intensity | strength of the peak which belongs to the Co-O bond in the radial distribution curve of the said catalyst for hydrogenation treatment after passing through a hydrogenation process and a regeneration process is shown. ]

  In addition, the processing atmosphere, processing temperature, and processing time of the regeneration processing in the present embodiment can be as follows. However, the following description does not mean that sufficient catalytic activity can be imparted to the regenerated hydrotreating catalyst as long as the processing atmosphere, the processing temperature, and the processing time satisfy the respective requirements. It goes without saying that the processing atmosphere, the processing temperature, and the processing time are appropriately selected so as to be determined as “good” in the step (3) of the regeneration processing condition selection method.

  The treatment atmosphere in the regeneration step is preferably an atmosphere in which molecular oxygen exists, for example, in the air, particularly in an air stream.

  The treatment temperature in the regeneration step varies depending on the history of the regenerative hydrotreating catalyst, but is preferably 250 to 380 ° C, more preferably 260 to 350 ° C, and even more preferably 280 to 320 ° C. Is done. A method of oxidizing and removing deposited coke and sulfur is preferably employed. When the heating temperature is lower than the lower limit temperature, there is a tendency that the removal of substances having reduced catalytic activity such as coke and sulfur content does not proceed efficiently. On the other hand, when the heating temperature exceeds the upper limit temperature, the active metal in the catalyst tends to decrease the activity of the resulting regenerated hydrotreating catalyst by forming a composite metal oxide or causing aggregation. is there.

  The regeneration treatment time is preferably 0.5 hours or more, more preferably 2 hours or more, further preferably 2.5 hours or more, and particularly preferably 3 hours or more. When the treatment time is less than 0.5 hours, the removal of substances having reduced catalytic activity such as coke and sulfur content tends not to proceed efficiently.

(Regenerative hydrogenation catalyst)
The regenerated hydrotreating catalyst obtained by the above production method preferably has a peak intensity ratio I / I ₀ in step (3) within the range of 1.22-1.35, more preferably It is 1.25 to 1.34, more preferably 1.27 to 1.33. When the peak intensity ratio I / I ₀ is within the above range, it is possible to sufficiently suppress the decrease in the catalytic activity due to the structural change of the cobalt oxide.

  The amount of residual carbon contained in the regenerated hydrotreating catalyst is preferably 0.15% by mass or more, more preferably 0.4% by mass or more, particularly preferably 0, based on the mass of the regenerated hydrotreating catalyst. 0.5 mass% or more, preferably 3.0 mass% or less, more preferably 2.5 mass% or less, and particularly preferably 2.0 mass% or less. When the amount is less than 0.15% by mass, active metal aggregation occurs due to the thermal history in the regeneration step, and the activity of the regenerated hydrotreating catalyst tends to decrease. On the other hand, when it exceeds 3.0% by mass, the activity of the regenerated hydrotreating catalyst tends to decrease due to the carbon blocking the active sites of the catalyst. In the present invention, “residual carbon” refers to carbon (coke) remaining in the regenerated hydrotreating catalyst after regenerating the used hydrotreating catalyst, and in the regenerated hydrotreating catalyst. The amount of residual carbon is measured in accordance with “Coal and cokes—elemental analysis method using equipment analyzer” defined in JIS M 8819.

(Usage of regenerated hydrogenation catalyst)
The regenerated hydrotreating catalyst according to this embodiment may be used alone as a catalyst for the hydrotreating process of the above-mentioned distillate petroleum fraction, or may be used in a layered manner with an unused catalyst. In the case of stacking with an unused catalyst, the ratio of the regenerated hydrotreating catalyst is not particularly limited, but it is not used from the viewpoint of reducing the amount of catalyst waste and ease of separating the catalyst when replacing the catalyst. 80 or more (mass ratio) is preferable with respect to the catalyst 100 used, and 120 or more (mass ratio) is more preferable.

  EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these examples.

[Examples 1 to 4, Comparative Examples 1 and 2]
(Unused catalyst and regenerated catalyst)
First, a catalyst in which cobalt and molybdenum as active metals were supported on an alumina carrier (unused catalyst, cobalt supported amount: 2.5 mass%, molybdenum supported amount: 22.9 mass%) was prepared. Next, a part of the catalyst was used in a kerosene hydrotreating facility for 2 years to obtain a used catalyst.

(Reproduction processing)
Next, the spent catalyst was subjected to a regeneration treatment for 5 hours at a treatment temperature shown in Table 1 in an air stream. The following XAFS analysis and evaluation of catalytic activity were performed on the regenerated catalysts of Examples 1 to 4 and Comparative Example 2 (single regenerated catalyst) thus obtained. In Comparative Example 1, the above-mentioned unused catalyst was used as it was, and XAFS analysis and catalytic activity were evaluated.

(XAFS analysis)
XAFS analysis was performed on the unused catalyst of Comparative Example 1 and each of the regenerated catalysts of Examples 1 to 4 and Comparative Example 2, and a radial distribution curve was obtained from the EXAFS spectrum of the Co K absorption edge of each catalyst. The intensity I ₀ or I of the peak attributed to the Co—O bond in (the main peak in the range of the interatomic distance of 0.16 nm ± 0.02 nm) was determined. Details of the procedure of the XAFS analysis are as described in the embodiment. Table 1 shows the peak intensity ratios I / I ₀ obtained in Examples 1 to 4 and Comparative Examples 1 and 2.

(Evaluation of catalytic activity)
For each of the unused catalyst or the plurality of regenerated catalysts, the catalytic activity was evaluated as follows.
First, the fixed bed continuous flow reactor was filled with the catalyst, and the catalyst was presulfided. Specifically, 1% by mass of DMDS was added to the kerosene fraction based on the mass of the fraction, and this was continuously supplied to the catalyst for 48 hours. Then, the above-mentioned kerosene fraction (without DMDS added) was used as a raw material oil, and a hydrogenation reaction was performed at a hydrogen partial pressure of 3 MPa, LHSV1h ⁻¹ , a hydrogen / oil ratio of 200 NL / L, and a reaction temperature of 300 ° C. The desulfurization rate constant was determined from the sulfur content in the product oil. In addition, the same reaction was performed using an unused catalyst corresponding to the regenerated catalyst 1 to obtain a desulfurization rate constant, and the specific activity of the regenerated catalyst 1 was calculated from these. The results are shown in Table 1.

From the results shown in Table 1, when the peak intensity ratio I / I ₀ is in the range of 1.24 to 1.32, it can be predicted that the specific activity of the once-regenerated catalyst with respect to the unused catalyst is 0.90 or more. .

[Example 5, Comparative Example 3]
In Example 5 and Comparative Example 3, regeneration treatment and XAFS analysis were performed in the same manner as described above except that the regeneration treatment temperature was 200 ° C. or 450 ° C., respectively. Table 2 shows the peak intensity ratios I / I ₀ obtained in Example 5 and Comparative Example 3.
Further, based on the correlation between the peak intensity ratio I / I ₀ and the catalyst activity obtained in Examples 1 to 4 and Comparative Examples 1 and 2, according to the regeneration treatment conditions of Example 5, The specific activity relative to the unused catalyst was predicted to be 0.90 or higher. On the other hand, according to the regeneration treatment conditions of Comparative Example 3, it was predicted that the specific activity of the once regenerated catalyst with respect to the unused catalyst would be less than 0.90.

Next, the catalytic activity of each regenerated catalyst of Example 5 and Comparative Example 3 was evaluated in the same manner as described above. The specific activity obtained is shown in Table 2.
As shown in Table 2, in both cases of Example 5 and Comparative Example 3, there was a good correlation between the catalytic activity predicted from the peak intensity ratio I / I ₀ and the actually evaluated catalytic activity.

Furthermore, the correlation between the peak intensity I / I ₀ and the specific activity obtained in Examples 1 to 5 and Comparative Examples 2 and 3 is shown in FIG. From the results shown in FIG. 3, when the peak intensity ratio I / I ₀ is in the range of 1.22 to 1.35, the specific activity of the once regenerated catalyst with respect to the unused catalyst can be predicted to be 0.90 or more. .

[Examples 6 and 7, Comparative Example 4]
A part of the regenerated catalyst of Example 4 was used in a kerosene hydrotreating facility for 2 years to obtain a used catalyst.
This spent catalyst was regenerated for 5 hours in the air stream at the treatment temperature shown in Table 3. The thus-obtained regenerated catalysts of Examples 6 and 7 and Comparative Example 4 (twice regenerated catalyst) were subjected to XAFS analysis and evaluation of catalytic activity in the same manner as described above. The obtained peak intensity ratio I / I ₀ and specific activity are shown in 3. The peak intensity I / I ₀ and specific activity shown in Table 3 are based on the unused catalyst of Comparative Example 1, respectively.

From the results shown in Table 3, if the peak intensity ratio I / I ₀ is within the range of 1.23 to 1.31, it can be predicted that the specific activity of the twice-regenerated catalyst with respect to the unused catalyst will be 0.80 or more. .

[Example 8]
In Example 8, regeneration treatment and XAFS analysis were performed in the same manner as described above except that the regeneration treatment temperature was 400 ° C. The peak intensity ratio I / I ₀ obtained in Example 8 is shown in Table 4.
Here, based on the correlation between the peak intensity ratio I / I ₀ obtained in Examples 6 and 7 and Comparative Example 4 and the catalyst activity, according to the regeneration treatment condition of Example 8, the unreacted catalyst of the twice-regenerated catalyst The specific activity relative to the catalyst used was predicted to be 0.80 or more.

Next, the catalyst activity of the regenerated catalyst of Example 8 was evaluated in the same manner as described above. The specific activity obtained is shown in Table 4.
As shown in Table 4, in Example 8, the catalyst activity predicted from the peak intensity ratio I / I ₀ and the actually evaluated catalyst activity showed a good correlation.

Furthermore, the correlation between the peak intensity I / I ₀ and the specific activity obtained in Examples 6 to 8 and Comparative Example 4 is shown in FIG. From the results shown in FIG. 4, if the peak intensity ratio I / I ₀ is in the range of 1.22-1.35, the specific activity of the twice-regenerated catalyst can be predicted to be 0.80 or more.

Claims (3)

A method of selecting a regeneration treatment condition when regenerating a hydrotreating catalyst for treating a distillate petroleum fraction,
An inorganic carrier containing aluminum oxide and a catalyst for hydrotreating containing cobalt supported on the inorganic carrier and before being used for hydrotreating are subjected to X-ray absorption fine structure analysis to obtain Co K absorption. A first step of obtaining a radial distribution curve from the broad X-ray absorption fine structure spectrum at the end, and obtaining an intensity I _{0 of} a peak attributed to a Co—O bond in the radial distribution curve;
The hydrotreating catalyst after the hydrotreating is regenerated under predetermined conditions, the regenerated catalyst is subjected to X-ray absorption fine structure analysis, and from the wide X-ray absorption fine structure spectrum of the Co K absorption edge. A second step of obtaining a radial distribution curve and obtaining an intensity I of a peak attributed to a Co-O bond in the radial distribution curve;
A ratio I / I ₀ of I obtained in the second step with respect to I ₀ obtained in the first step is determined, and a correlation between the peak intensity ratio I / I ₀ obtained in advance and the catalyst activity is obtained. A third step of determining whether the conditions of the regeneration process in the second step are good or not based on:
A method for selecting a regeneration treatment condition for a hydrotreating catalyst.   An inorganic carrier containing aluminum oxide and a hydrotreating catalyst containing cobalt supported on the inorganic carrier after being used for hydrotreating to treat a distillate petroleum fraction, A method for producing a regenerated hydrotreating catalyst, comprising a step of regenerating under the conditions selected by the method according to Item 1. The method according to claim 2, wherein the selected condition satisfies a condition represented by the following formula (1).
1.22 ≦ I / I ₀ ≦ 1.35 (1)
[In the formula (1), I ₀ represents the intensity of a peak attributed to a Co—O bond in the radial distribution curve of the hydrotreating catalyst before being used for hydrotreating, and I represents hydrogen The intensity | strength of the peak which belongs to the Co-O bond in the radial distribution curve of the said catalyst for hydrogenation treatment after passing through a hydrogenation process and a regeneration process is shown. ]

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