JP2016075571A - Method for evaluating hydrocarbon oil used in desulfurization reaction, method for desulfurizing hydrocarbon oil, and method for producing desulfurized oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide method for evaluating hydrocarbon oil that is capable of evaluating whether the hydrocarbon oil is suitable for desulfurization reaction.SOLUTION: A method for evaluating hydrocarbon oil used in desulfurization reaction comprises: a catalyzing step of causing a hydrotreating catalyst to catalyze part of hydrocarbon oil; a heat treatment step of performing heat treatment on the hydrotreating catalyst subjected to the catalyzing step; and an observation step of observing the hydrotreating catalyst subjected to the heat treatment under a transmission electron microscope so as to observe the presence/absence of a graphite lattice image.SELECTED DRAWING: None

Description

  The present invention relates to a method for evaluating a hydrocarbon oil to be subjected to a desulfurization reaction, a method for desulfurizing a hydrocarbon oil, and a method for producing a desulfurized oil.

  In recent years, demand for petroleum products has become lighter, and demand for heavy oil has been sluggish. For this reason, when producing light oil from crude oil, it has been studied to use the fraction used as a base material for heavy oil for light oil.

  In addition, examples of the base material for heavy oil include atmospheric distillation residue, vacuum distillation residue, vacuum gas oil, catalytic cracking gas oil, etc., and their use is also being studied. For example, Patent Literature 1 discloses a diesel light oil composition in which a small amount of cracked light oil is blended with a deep desulfurized light oil base material obtained by mixing and passing straight run light oil and cracked light oil in a deep desulfurization apparatus. Yes.

JP-A-8-259966

  As described above, it is desired that the heavy oil base material be effectively used as light oil. However, when the heavy oil base material is subjected to a hydrorefining treatment, there are cases in which problems such as an increase in the rate of deterioration of the hydrorefining catalyst and a shortened catalyst life may occur. In addition, while there is a large difference in the degradation rate of the hydrorefining catalyst depending on the type of hydrocarbon oil to be subjected to hydrorefining treatment, the degree of degradation of the hydrorefining catalyst by the hydrocarbon oil is appropriately evaluated in advance. The method has not been known so far.

  One of the objects of the present invention is to provide a hydrocarbon oil evaluation method for evaluating whether it can be suitably applied to a conventional desulfurization reaction. Another object of the present invention is to sufficiently suppress deterioration of the hydrorefining catalyst while using as a feedstock a hydrocarbon oil that has been evaluated to be unsuitable for conventional desulfurization reactions by the above evaluation method. An object of the present invention is to provide a method for desulfurizing hydrocarbon oil. Furthermore, the other object of this invention is to provide the manufacturing method of desulfurization oil which can obtain desulfurization oil efficiently using the hydrocarbon oil evaluated by the said evaluation method as raw material oil.

  The present inventors have found that the degradation of the hydrorefining catalyst is due to the deposition of high-density coke formed from aromatic components, and hydrogenated hydrocarbon oils containing basic nitrogen components in advance. It discovered that the catalyst deterioration by the said high-density coke can be suppressed by using for a refinement | purification catalyst. Furthermore, the present inventors heat-treat the hydrorefining catalyst after being brought into contact with the hydrocarbon oil, and observe it with a transmission electron microscope (TEM), whereby the hydrocarbon oil tends to cause high-density coke deposition. It has been found that it can be evaluated whether or not, and the present invention has been completed.

  One aspect of the present invention relates to a method for evaluating a hydrocarbon oil subjected to a desulfurization reaction. The evaluation method includes a contacting step in which a part of a hydrocarbon oil is brought into contact with a hydrorefining catalyst, a heat treatment step in which the hydrotreating catalyst that has undergone the contacting step is heat-treated, and the heat-treated hydrotreating catalyst is permeated. An observation step of observing the presence or absence of a graphite lattice image by observing with a scanning electron microscope.

  In the above evaluation method, the hydrocarbon oil in which the graphite lattice image is observed easily forms high-density coke on the hydrorefining catalyst in the desulfurization reaction, and easily deteriorates the hydrorefining catalyst. On the other hand, a hydrocarbon oil in which no graphite lattice image is observed hardly forms high-density coke in the desulfurization reaction, and the degree of deterioration of the hydrotreating catalyst is small. That is, according to the evaluation method, it is possible to easily evaluate whether or not the hydrocarbon is likely to cause deterioration of the hydrorefining catalyst in the desulfurization reaction.

  Another aspect of the present invention relates to a hydrocarbon oil desulfurization method. The desulfurization method includes a first step of bringing the first hydrocarbon oil into contact with the hydrorefining catalyst, and a second step of bringing the second hydrocarbon oil into contact with the hydrorefining catalyst having undergone the first step. The process is provided. In the desulfurization method, the second hydrocarbon oil includes the other part of the hydrocarbon oil in which a graphite lattice image is observed by the evaluation method. In the desulfurization method, the first hydrocarbon oil contains a basic nitrogen content, and the content ratio of the basic nitrogen content is higher than the content ratio of the basic nitrogen content in the second hydrocarbon oil. . Further, in the desulfurization method, the aromatic content in the first hydrocarbon oil is lower than the aromatic content in the second hydrocarbon oil.

  According to the desulfurization method, by using the hydrorefining catalyst that has passed through the first step, the desulfurization treatment (hydrorefining treatment) of the second hydrocarbon oil in which the graphite lattice image is observed by the evaluation method, This can be carried out while sufficiently suppressing deterioration of the hydrotreating catalyst. That is, according to the above-mentioned desulfurization method, the hydrorefining catalyst is sufficiently deteriorated while using the hydrocarbon oil (second hydrocarbon oil), which was difficult to be applied to the conventional desulfurization reaction from the viewpoint of catalyst deterioration, as a raw material oil. The hydrorefining treatment can be carried out while suppressing the above.

  In one embodiment, the basic nitrogen content may include anilines.

  In one embodiment, the aromatic component may include at least one bicyclic aromatic component selected from the group consisting of naphthalenes and biphenyls.

  In one embodiment, the first hydrocarbon oil may include a direct desulfurized gas oil.

  In one aspect, in the desulfurization method, the first step and the second step can be alternately performed a plurality of times.

  Still another aspect of the present invention relates to a method for producing a desulfurized oil. In the production method, the desulfurized oil can be obtained by desulfurizing the raw material oil by the desulfurization method.

  According to the said manufacturing method, desulfurized oil can be obtained efficiently, using the 2nd hydrocarbon oil by which the graphite lattice image was observed by the said evaluation method as raw material oil.

  Still another aspect of the present invention relates to a method for producing a further desulfurized oil. The production method includes a step of bringing the other part of the hydrocarbon oil in which no graphite lattice image is observed in the evaluation method described above into contact with a hydrorefining catalyst.

  According to the above production method, desulfurized oil can be efficiently removed while sufficiently suppressing deterioration of the hydrorefining catalyst by bringing the hydrocarbon oil, which has been evaluated as having a low deterioration rate, into contact with the hydrotreating catalyst. Can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the evaluation method of hydrocarbon oil which can evaluate whether it can apply suitably for the conventional desulfurization reaction can be provided. Further, according to the present invention, the carbonization that can sufficiently suppress the deterioration of the hydrorefining catalyst while using the hydrocarbon oil evaluated as unsuitable for the conventional desulfurization reaction by the above evaluation method as the raw material oil. A method for desulfurizing hydrogen oil can be provided. Furthermore, according to this invention, the manufacturing method of desulfurization oil which can obtain desulfurization oil efficiently can be provided using the hydrocarbon oil evaluated by the said evaluation method as raw material oil.

It is the schematic for demonstrating a comprehensive two-dimensional GC system. It is a flowchart which shows an example of the procedure when calculating | requiring the content rate of the basic nitrogen content of hydrocarbon oil, and the content rate of anilines. It is a figure which shows an example of the two-dimensional chart obtained by a comprehensive two-dimensional GC system (detector: NCD). 6 is a diagram showing a TEM observation result in Example 1. FIG. 10 is a diagram showing a TEM observation result in Example 3. FIG. FIG. 6 is an enlarged view of FIG. 5. It is a figure which shows the intensity | strength profile of the lattice image observed in FIG.

  According to the present embodiment, a method for evaluating a hydrocarbon oil to be subjected to a desulfurization reaction includes a contacting step in which a part of the hydrocarbon oil is brought into contact with a hydrorefining catalyst, and a heat treatment step in which the hydrorefining catalyst that has undergone the contacting step is heat-treated. And an observation step of observing the presence or absence of a graphite lattice image by observing the heat-treated hydrorefining catalyst with a transmission electron microscope (TEM).

  According to the evaluation method, the degree of deterioration of the hydrorefining catalyst due to the hydrocarbon oil subjected to the desulfurization reaction can be evaluated.

  In the above evaluation method, the hydrocarbon oil in which the graphite lattice image is observed easily forms high-density coke on the hydrorefining catalyst in the desulfurization reaction, and the degree of deterioration of the hydrorefining catalyst is large. On the other hand, a hydrocarbon oil in which no graphite lattice image is observed hardly forms high-density coke in the desulfurization reaction, and the degree of deterioration of the hydrorefining catalyst is small. That is, according to the above evaluation method, it can be easily evaluated whether or not the hydrocarbon is likely to cause deterioration of the hydrorefining catalyst in the desulfurization reaction. The reason why the hydrocarbon oil can be evaluated in this way is that the degradation of the hydrorefining catalyst is due to the deposition of high-density coke formed from aromatic components. It is thought that the ease of depositing high-density coke can be evaluated by TEM observation.

  More specifically, the present inventors infer the following effects as follows.

  First, it is believed that degradation of a hydrorefining catalyst due to desulfurization of hydrocarbon oil occurs because the desulfurization reaction is inhibited by coke (carbonaceous matter) deposited on the catalyst during the reaction process. It is considered that coke is deposited at acid sites on the support surface of the desulfurization catalyst, and as the coke is deposited, the sulfur content in the hydrocarbon oil is hindered from approaching the active species, so that the reactivity is lowered.

  Here, when the coke deposition behavior on the catalyst is considered separately for the coke formation process and the growth process, aromatics and basic nitrogen in the feedstock are deposited (adsorbed) in the coke formation process. ) The adsorption behavior to the Lewis acid sites present on the surface of the catalyst carrier (for example, alumina) is End-on (η1 coordination) for basic nitrogen content, Side-on (η6 coordination) for aromatic content. ). The growth of coke adsorbed on the end-on is considered to grow in a direction perpendicular to the support surface, whereas the growth of coke adsorbed on the side-on is considered to be stacked in parallel with the support surface. In addition, since the coke species adsorbed and grown by End-on are directed in various directions on the surface of the carrier, the coke density on the surface is estimated to be low. On the other hand, since the coke species adsorbed and grown by Side-on are laminated on the surface of the carrier, it is estimated that the coke density is increased. It is considered that such a difference, that is, a difference in adsorption behavior in the coke generation process, affects the amount of coke deposited in the subsequent coke growth process, and as a result, a difference occurs in the deterioration behavior of the catalyst.

  Moreover, it is thought that the high density coke derived from the aromatic component is markedly hindered from approaching the active species of the sulfur content by being stacked and deposited near the active species of the catalyst. In contrast, coke derived from basic nitrogen is formed as low-density coke that accumulates on the surface of the carrier and does not deposit, so even if it is deposited near the active species, it may cause a decrease in reactivity. It seems difficult.

  The above evaluation method pays attention to the difference in the coke deposition behavior as described above, and finds the relationship between the high density coke deposition that causes the decrease in the activity of the hydrotreating catalyst and the graphite lattice image in the TEM observation. This is applied to the evaluation of hydrocarbon oil to be subjected to hydrorefining treatment.

  Hereafter, each process of the said evaluation method is demonstrated in detail.

(Contact process)
The contacting step is a step of bringing a part of the hydrocarbon oil into contact with the hydrorefining catalyst.

  In the present specification, the hydrocarbon oil has a hydrocarbon as a main component (at least 75% by mass, preferably 90% by mass or more, more preferably 98% by mass or more) and is liquid at a temperature of 15 ° C. and 1 atm. Indicates.

The hydrocarbon oil may have a density of 0.83 to 0.89 g / cm ³ at 15 ° C., for example. Further, the density of the hydrocarbon oil at 15 ° C. is preferably 0.83 to 0.88 g / cm ³ , more preferably 0.84 to 0.87 g / cm ³ , and still more preferably 0.86 to 0.86. 0.87 g / cm ³ . When the density of the hydrocarbon oil is within the above range, an effect of improving the fuel efficiency of the product light oil is exhibited. In this specification, the density at 15 ° C. conforms to “Oscillating Density Test Method” of “Crude Oil and Petroleum Products—Density Test Method and Density / Mass / Capacity Conversion Table (Excerpt)” prescribed in JIS K 2249. The measured density is shown.

  The hydrocarbon oil may have a 90% by volume distillation temperature of 320 to 370 ° C, for example. The 90 vol% distillation temperature of the hydrocarbon oil is preferably 320 to 360 ° C, more preferably 330 to 355 ° C. When the 90% by volume distillation temperature of the hydrocarbon oil is within the above range, an effect of suppressing particulate matter (PM) of the product gas oil is exhibited.

  The hydrocarbon oil may have a 10% by volume distillation temperature of 200 to 280 ° C, for example. The 10 vol% distillation temperature of the hydrocarbon oil is preferably 210 to 275 ° C, more preferably 220 to 270 ° C. When the 10 vol% distillation temperature of the hydrocarbon oil is within the above range, an effect that the oxidation stability of the product gas oil is high is exhibited.

  In this specification, the distillation properties of hydrocarbon oil, such as 90% by volume distillation temperature and 10% by volume distillation temperature, are measured in accordance with “Petroleum product-distillation test method” prescribed in JIS K 2254. The

In the contacting step, the conditions for bringing a part of the hydrocarbon oil into contact with the hydrorefining catalyst are not particularly limited. For example, the temperature condition at the time of contact is preferably 250 to 420 ° C, and more preferably 270 to 400 ° C. In addition, LHSV (liquid space velocity, ratio of hydrocarbon oil supply rate to catalyst filling volume) in the contacting step can be, for example, 0.1 to 5 h ⁻¹ , preferably 0.5 to 3 h ⁻¹ . is there.

  In the contact step, hydrogen may be circulated together with the hydrocarbon oil. The hydrogen partial pressure in the contacting step can be, for example, 1 to 10 MPa, and preferably 3 to 8 MPa. Moreover, hydrogen oil ratio (hydrogen / oil ratio) can be 30-500 NL / L, for example, Preferably it is 60-300 NL / L.

Moreover, when desulfurizing the hydrocarbon oil in the contacting step, for example, the hydrogen partial pressure is 1 to 10 MPa, more preferably 3 to 8 MPa, LHSV 0.1 to 5 h ⁻¹ , the hydrogen oil ratio 30 to 500 NL / L, more preferably It is preferable that the hydrocarbon oil is brought into contact with the hydrotreating catalyst under the conditions of 60 to 300 NL / L and a reaction temperature of 250 to 420 ° C, more preferably 270 to 400 ° C.

  The hydrocarbon oil may include, for example, a hydrocarbon oil derived from crude oil. For example, straight-run gas oil (LGO), catalytic cracked gas oil (LCO) obtained from crude oil, and hydrorefined products such as atmospheric distillation residual oil, vacuum distillation residual oil, vacuum gas oil, and solvent debris oil can be used. .

  The straight-run gas oil refers to a gas oil fraction obtained by subjecting crude oil to atmospheric distillation.

  Examples of the catalytic cracking gas oil include a gas oil fraction obtained by catalytic cracking of atmospheric distillation residual oil, vacuum gas oil, solvent-depleted oil, or hydrorefined oil thereof using a fluid catalytic cracking apparatus.

  Examples of the hydrorefined product include a direct desulfurized gas oil (RDS-GO) obtained by hydrorefining atmospheric distillation residue, an indirect desulfurized gas oil obtained by hydrotreating a vacuum distillation residue, and a vacuum gas oil. And hydrorefined oil of reduced pressure gas oil obtained by hydrorefining, and hydrorefined oil of solvent devolatilized oil obtained by hydrotreating solvent devolatilized oil (DAO).

  As the hydrorefining catalyst, any hydrotreating catalyst used for hydrocarbon oil desulfurization can be used without particular limitation.

  From the standpoint that the effect of suppressing the deterioration of the catalyst due to the formation of the above-mentioned low density coke is remarkably exhibited, the hydrorefining catalyst is a catalyst containing an inorganic oxide carrier, that is, a catalyst in which an active metal is supported on an inorganic oxide carrier. Preferably there is. In addition, the inorganic oxide support is preferably a porous body from the viewpoint of increasing the contact area and exhibiting the above effects more remarkably.

  Examples of inorganic oxide carriers include oxides such as alumina, silica, titania, magnesia, zirconia, and boria; two or more composite oxides selected from alumina, silica, titania, magnesia, zirconia, boria, and the like, specific examples As composite oxides such as silica-alumina, silica-titania, silica-zirconia, silica-magnesia, silica-alumina-titania, silica-alumina-zirconia; Y-type zeolite, stabilized Y-type zeolite, β-type zeolite, Examples thereof include supports containing inorganic oxides such as mordenite-type zeolite and zeolite such as MCM-22. Furthermore, the inorganic oxide support may contain phosphorus as an oxide from the viewpoint of improving the catalytic activity.

  Examples of the active metal include molybdenum (Mo), tungsten (W), cobalt (Co), nickel (Ni), and the like.

(Heat treatment process)
The heat treatment step is a step of heat-treating the hydrorefining catalyst that has undergone the contact step.

  By heat-treating the hydrotreating catalyst, the high-density coke deposited on the hydrotreating catalyst develops a laminated structure, and in the TEM observation in the observation process described later, a lattice image of graphite that was not recognized before the heat treatment was observed. The

  In the heat treatment step, the conditions for heat treating the hydrorefining catalyst are not particularly limited. For example, from the viewpoint of effectively observing the graphite lattice image in the TEM observation in the observation step described later, the temperature condition during the heat treatment is preferably 450 to 700 ° C, and more preferably 480 to 600 ° C. . From the same viewpoint, the time required for the heat treatment is preferably 0.5 to 12 hours, and more preferably 1 to 6 hours. The heat treatment is preferably performed in a nitrogen atmosphere.

  More specifically, the heat treatment condition is that the temperature is raised from room temperature to 500 ° C. over 1 hour in a nitrogen atmosphere, then held at 500 ° C. for 1 hour, and then cooled from 500 ° C. to room temperature over 8 hours. The method is preferred.

(Observation process)
The observation step is a step of observing the presence or absence of a graphite lattice image by TEM observation of the hydrorefining catalyst heat-treated in the heat treatment step. By observing the presence or absence of the graphite lattice image, it is possible to evaluate the degree of deterioration of the hydrocarbon oil subjected to the hydrorefining catalyst with respect to the hydrorefining catalyst.

  A sample for TEM observation of the heat-treated hydrorefining catalyst is produced by a method such as a focused ion beam (FIB) processing described below. The FIB processing is performed by a procedure in which a pellet-like catalyst obtained by removing a part of the heat-treated hydrorefining catalyst is protected by Pt coating or the like, excavated by Ga ion irradiation or the like, and thinned to about 100 nm.

TEM observation can be performed by the following procedure.
(TEM observation)
A TEM photograph of the hydrotreating catalyst is taken under the following conditions using TEM.
Electron gun: LaB6
Accelerating voltage: 200kV
Imaging magnification: 1.5 million times When a lattice image is observed in the obtained TEM photograph, the surface interval of the lattice image is read to check whether it corresponds to the surface interval of the graphite (002) surface.

  In the present specification, the graphite lattice image refers to a lattice image corresponding to a surface interval of about 0.35 nm of the (002) plane. Whether or not the laminated structure based on the lattice image is observed is observed by TEM observation according to the method described above.

  Although the evaluation method according to this embodiment has been described above, the present invention is not limited to the above embodiment.

  Next, the hydrocarbon oil desulfurization method according to the present invention will be described. The hydrocarbon oil desulfurization method according to the present invention includes a case of desulfurizing a hydrocarbon oil in which a graphite lattice image is observed by the above-described evaluation method, and a case of hydrocarbon oil in which a graphite lattice image is not observed by the above-described evaluation method. The desulfurization method differs depending on the case of desulfurization. Hereinafter, each case will be described.

  The hydrocarbon oil desulfurization method according to the first embodiment includes a first step of bringing the first hydrocarbon oil into contact with the hydrorefining catalyst, and a second carbonization in the hydrorefining catalyst that has passed through the first step. A second step of contacting the hydrogen oil.

  Here, the second hydrocarbon oil includes the other part of the hydrocarbon oil in which the graphite lattice image is observed by the above-described evaluation method. That is, the hydrocarbon oil is a hydrocarbon oil that tends to deteriorate the hydrorefining catalyst.

  The first hydrocarbon oil contains a basic nitrogen content, and the content ratio of the basic nitrogen content in the first hydrocarbon oil is higher than the content ratio of the basic nitrogen content in the second hydrocarbon oil. The content ratio of the aromatic component in the first hydrocarbon oil is lower than the content ratio of the aromatic component in the second hydrocarbon oil.

  In the above desulfurization method, low-density coke is deposited near the active species of the catalyst through the first step of bringing the first hydrocarbon oil containing a large amount of basic nitrogen into contact with the hydrorefining catalyst in advance. Thereafter, it is considered that the deposition of high-density coke when the second hydrocarbon oil containing a large amount of aromatics is brought into contact is suppressed, and as a result, deterioration of the catalyst is suppressed.

  Hereinafter, each process of the said desulfurization method is demonstrated in detail.

(First step)
The first step is a step of bringing the first hydrocarbon oil containing basic nitrogen content into contact with the hydrorefining catalyst. By bringing the first hydrocarbon oil into contact with the hydrorefining catalyst in the first step, low-density coke is formed in the vicinity of the active species of the hydrorefining catalyst. Is done.

  In the present specification, the basic nitrogen content is UOP test method no. The compound detected by the measurement based on 269-90 is shown.

  The basic nitrogen component is a component having basic nitrogen (that is, a nitrogen atom that functions as a Lewis base), and such basic nitrogen component has an unshared electron pair of nitrogen atom at the Lewis acid point on the catalyst support surface. To form the low density coke described above.

  The first hydrocarbon oil preferably contains at least anilines as a basic nitrogen component. According to anilines, the above-mentioned low density coke is more suitably formed, and the catalyst deterioration in the second step is further remarkably suppressed.

  In this specification, aniline refers to aniline or a compound having a structure in which one or more hydrogen atoms of aniline are substituted with a substituent. Anilines have an aniline skeleton composed of a benzene ring and a nitrogen atom bonded thereto, and the above-described low density coke is preferably formed by the aniline skeleton.

  Anilines may have, for example, a hydrocarbon group having 1 to 8 carbon atoms as the substituent. Moreover, when aniline has a 2 or more hydrocarbon group as a substituent, it is preferable that the carbon number of the hydrocarbon group is 10 or less.

  The basic nitrogen content in the first hydrocarbon oil may be higher than the basic nitrogen content in the second hydrocarbon oil described below. By bringing the first hydrocarbon oil containing more basic nitrogen than the second hydrocarbon oil into contact with the hydrorefining catalyst in advance, it is possible to obtain the effect of suppressing the above-described catalyst deterioration. In the present specification, the content ratio of basic nitrogen content is UOP test method no. It is measured by the measuring method based on 269-90.

  From the viewpoint of depositing the low density coke more efficiently, the content ratio of the basic nitrogen content of the first hydrocarbon oil may be 50 mass ppm or more with respect to the total amount of the first hydrocarbon oil. Preferably, it is 60 mass ppm or more.

  As described later, the first hydrocarbon oil may contain a sulfur content, and desulfurized oil may be obtained from the first hydrocarbon oil in the first step. In this case, the basic nitrogen content in the first hydrocarbon oil is preferably 150 ppm by mass or less and 100 ppm by mass or less based on the total amount of the first hydrocarbon oil. More preferred. When there is too much basic nitrogen content, the desulfurization reaction of the first hydrocarbon oil may not sufficiently proceed. That is, the catalyst in the second step is carried out while the desulfurization reaction of the first hydrocarbon oil is effectively carried out by setting the content ratio of the basic nitrogen content in the first hydrocarbon oil to the upper limit value or less. A sufficient effect of suppressing deterioration can be obtained.

  As described above, the first hydrocarbon oil preferably contains anilines as a basic nitrogen component. The content ratio of anilines in the first hydrocarbon oil is preferably 30 mass ppm or more, and more preferably 40 mass ppm or more, based on the total amount of the first hydrocarbon oil. In the first hydrocarbon oil, the content ratio of anilines to the total amount of basic nitrogen is preferably 60% by mass or more, and more preferably 70% by mass or more.

  In addition, the method to obtain | require the content rate of the aniline with respect to the whole quantity of a 1st hydrocarbon oil and the content rate of the aniline with respect to the whole quantity of basic nitrogen content is demonstrated.

  FIG. 1 is a schematic diagram for explaining a comprehensive two-dimensional GC system used in the method according to the present embodiment. A comprehensive two-dimensional GC system 100 shown in FIG. 1 includes a sample introduction unit 10, a first column 12, a modulation column 14, and a second column 18 for separating a sample introduced from the sample introduction unit 10, and a separation. A splitter 20 for sending the processed sample to a detector, and a flame ionization detector (FID) 22, a chemiluminescent nitrogen detector (NCD) 24, and a mass spectrometer (MS) 30 as detectors. . The comprehensive two-dimensional GC system 100 also includes a modulator unit 50 having a heating unit 15 for heating the modulation column 14 with a heating gas and a cooling unit 16 for cooling with the liquid nitrogen.

  In the comprehensive two-dimensional GC system 100, the sample introduced from the sample introduction unit 10 is separated for each boiling point by the first column 12. The separated components are cooled by liquid nitrogen in the modulator unit 50 and temporarily trapped in the modulation column 14. Next, the trapped component moves to the second column 18 each time by spraying a heating gas on the modulation column 14 trapping the separation component at a constant time interval. The components that have moved to the second column 18 are separated for each polarity, and sent to three types of detectors by the splitter 20.

  Next, measurement and analysis using a comprehensive two-dimensional GC system will be described.

  FIG. 2 is a flowchart showing an example of a procedure for obtaining the content ratio of basic nitrogen and the content ratio of anilines in hydrocarbon oil. In step S21, NCD data and MS data of the sample are obtained using the two-dimensional GC. In step S22, the obtained NCD data and MS data are two-dimensionally processed. In step S23, the peak of anilines is identified based on the MS data, and the volume ratio of the corresponding NCD peak is obtained. In step S24, volume values of all detected peaks are obtained. In step S25, the ratio of the volume value of the NCD peak of anilines to the volume ratio of all NCD peaks is calculated. In step S26, the total nitrogen concentration in the sample is determined by the JIS-K 2609 raw material and petroleum product-nitrogen content test method. In step S27, the concentration (mass ppm) of anilines in the sample is calculated using the determined total nitrogen concentration and the ratio of anilines. In step S28, the UOP test method No. The concentration of basic nitrogen in the sample is determined according to 269-90. In step S29, the ratio of anilines to the total content of total basic nitrogen is calculated based on the concentration of basic nitrogen and the concentration of anilines. In this example, each step is performed in the order shown in FIG. 2, but some steps may be performed simultaneously or the order may be changed.

  In step S21, for example, measurement can be performed under the analysis conditions shown in Table 1.

  The sample can be subjected to a predetermined pretreatment. For example, when analyzing anilines, a methanol extract of a sample can be used as a sample for measurement. Methanol extraction can be performed by the following procedure. First, an equal amount of methanol and sample are collected in a container and shaken vigorously for 5 minutes. Then, it is left still for 1 hour or more, and a methanol layer is collected, and this is used as a sample for measurement.

  In step S22, two-dimensional processing can be performed using the analysis software GC Image. Thereby, for example, the two-dimensional chart shown in FIG. 3 is obtained.

  FIG. 3 is a diagram showing an example of a two-dimensional chart obtained by a comprehensive two-dimensional GC system (detector: NCD). In the chart of FIG. 3, peaks of basic nitrogen components decomposed in order of boiling point and polarity are shown. Based on MS data, a peak corresponding to anilines can be identified, and the volume value of the peak can be obtained. In this way, step S23 can be performed.

  In step S24, the volume values of all the peaks are obtained. At this time, it is preferable to set a threshold value similar to that for obtaining the volume value in step S23.

  The first hydrocarbon oil may contain a nitrogen content other than the basic nitrogen content. The content ratio of nitrogen in the first hydrocarbon oil (content ratio of nitrogen content including basic nitrogen content) may be, for example, 50 mass ppm or more based on the total amount of the first hydrocarbon oil. It may be at least ppm by mass. Moreover, the content rate of the nitrogen content in a 1st hydrocarbon oil may be 300 mass ppm or less with respect to the whole quantity of a 1st hydrocarbon oil, for example, and may be 200 mass ppm or less. If the nitrogen content is high, the initial activity of the catalyst tends to be low. Moreover, since the influence of the catalyst poisoning by nitrogen is small when the content rate of nitrogen content is low, the initial catalytic activity tends to be high. In the present specification, the nitrogen content is measured in accordance with JIS K 2609 “Crude oil and petroleum products—nitrogen content test method”.

  The first hydrocarbon oil may contain an aromatic content, but the content of aromatic content in the first hydrocarbon oil is the content of aromatic content in the second hydrocarbon oil. Fewer. The aromatic content in the first hydrocarbon oil is, for example, preferably 33% by volume or less, more preferably 30% by volume or less, based on the total amount of the first hydrocarbon oil. . In addition, the content of the aromatic component in the first hydrocarbon oil may be 10% by volume or more, or 20% by volume or more with respect to the total amount of the first hydrocarbon oil. Within such a range, even if the first hydrocarbon oil contains an aromatic component, low-density coke due to the basic nitrogen component is sufficiently formed in the vicinity of the catalytically active species, and the above-described effects are remarkably obtained. be able to.

  The first hydrocarbon oil may contain a sulfur content. When a hydrocarbon oil containing a sulfur content is used as the first hydrocarbon oil, the desulfurization reaction of the hydrocarbon oil can also be performed in the first step. Thus, the low-density coke is formed while the desulfurization reaction of the first hydrocarbon oil is performed in the first step, and the desulfurization reaction of the second hydrocarbon oil is performed in the second step. A highly efficient desulfurized oil production process can be realized.

  The content ratio of the sulfur content in the first hydrocarbon oil may be, for example, 0.5% by mass or more and 0.8% by mass or more with respect to the total amount of the first hydrocarbon oil. . Moreover, the content ratio of the sulfur content in the first hydrocarbon oil is preferably 2.0% by mass or less, more preferably 1.5% by mass or less, with respect to the total amount of the first hydrocarbon oil. is there. If the sulfur content is high, the catalyst life tends to be short. In addition, if the sulfur content is low, it is necessary to use an expensive hydrocarbon oil having a low sulfur content, which is not economical. In addition, in this specification, the content rate of a sulfur content is measured based on the "radiation type excitation method" of "Crude oil and petroleum products-sulfur content test method" prescribed | regulated to JISK2541-1992.

For example, the first hydrocarbon oil may have a density at 15 ° C. of 0.83 to 0.89 g / cm ³ . The density of the first hydrocarbon oil at 15 ° C. is preferably 0.83 to 0.88 g / cm ³ , more preferably 0.84 to 0.87 g / cm ³ , and still more preferably 0. .84 to 0.86 g / cm ³ . When the density of the first hydrocarbon oil is within the above range, an effect of improving the fuel efficiency of the product light oil is exhibited. In this specification, the density at 15 ° C. conforms to “Oscillating Density Test Method” of “Crude Oil and Petroleum Products—Density Test Method and Density / Mass / Capacity Conversion Table (Excerpt)” prescribed in JIS K 2249. The measured density is shown.

  For example, the first hydrocarbon oil may have a 90% by volume distillation temperature of 320 to 370 ° C. The 90 volume% distillation temperature of the first hydrocarbon oil is preferably 320 to 360 ° C, more preferably 330 to 355 ° C. When the 90% by volume distillation temperature of the first hydrocarbon oil is within the above range, an effect of suppressing particulate matter (PM) of the product gas oil is exhibited.

  The first hydrocarbon oil may have a 10% by volume distillation temperature of 200 to 280 ° C, for example. The 10 vol% distillation temperature of the first hydrocarbon oil is preferably 210 to 275 ° C, more preferably 220 to 270 ° C. When the 10% by volume distillation temperature of the first hydrocarbon oil is within the above range, the effect that the oxidation stability of the product gas oil is high is exhibited.

In the first step, the conditions for bringing the first hydrocarbon oil into contact with the hydrorefining catalyst are not particularly limited. For example, from the viewpoint of forming the low-density coke more efficiently, the temperature condition at the time of contact is preferably 250 to 420 ° C, and more preferably 270 to 400 ° C. Moreover, LHSV (liquid space velocity, ratio of hydrocarbon oil supply rate to catalyst filling volume) in the first step can be set to, for example, 0.1 to 5 h ⁻¹ , preferably 0.5 to 3 h ^{−. 1} . Depending on the catalyst, in order to facilitate adsorption of anilines on the catalyst, the reaction temperature in the first step is preferably 10 to 30 ° C. higher than the reaction temperature in the second step.

  In the first step, hydrogen may be circulated together with the first hydrocarbon oil. The hydrogen partial pressure in the first step can be set to, for example, 1 to 10 MPa, and preferably 3 to 8 MPa. Moreover, hydrogen oil ratio (hydrogen / oil ratio) can be 30-500 NL / L, for example, Preferably it is 60-300 NL / L.

  In addition, when the first hydrocarbon oil is desulfurized in the first step, the first carbonization after contacting the hydrorefining catalyst in the first step in order to satisfy the sulfur content regulation in the product gas oil. You may drive | operate so that the content rate of the sulfur content of hydrogen oil (1st production | generation oil) may be 7-15 mass ppm. At this time, it is preferable to operate | move so that it may become 7-10 mass ppm. By operating in this way, the first product oil can be suitably used as product light oil. In addition, the operation period of the first step is preferably 10 days or longer, and more preferably 20 days or longer. By extending this period, the period which processes low quality raw material oil becomes long, and economical efficiency improves.

  The hydrocarbon oil may include, for example, a hydrocarbon oil derived from crude oil. For example, straight-run gas oil (LGO), catalytic cracked gas oil (LCO) obtained from crude oil, and hydrorefined products such as atmospheric distillation residual oil, vacuum distillation residual oil, vacuum gas oil, and solvent debris oil can be used. .

  The straight-run gas oil refers to a gas oil fraction obtained by subjecting crude oil to atmospheric distillation.

  Examples of the catalytic cracking gas oil include a gas oil fraction obtained by catalytic cracking of atmospheric distillation residual oil, vacuum gas oil, solvent-depleted oil, or hydrorefined oil thereof using a fluid catalytic cracking apparatus.

  Examples of the hydrorefined product include a direct desulfurized gas oil (RDS-GO) obtained by hydrorefining atmospheric distillation residue, an indirect desulfurized gas oil obtained by hydrotreating a vacuum distillation residue, and a vacuum gas oil. And hydrorefined oil of reduced pressure gas oil obtained by hydrorefining, and hydrorefined oil of solvent devolatilized oil obtained by hydrotreating solvent devolatilized oil (DAO).

  The first hydrocarbon oil may be prepared, for example, by adding a basic nitrogen content to a hydrocarbon oil that does not contain a basic nitrogen content or has a low basic nitrogen content. The first hydrocarbon oil is prepared, for example, by adding a hydrocarbon oil containing a large amount of basic nitrogen to a hydrocarbon oil containing no basic nitrogen content or low basic nitrogen content. It may be.

  In one embodiment, as the first hydrocarbon oil, a hydrocarbon oil obtained by adding a desulfurized gas oil directly to a straight-run gas oil can be suitably used. Direct desulfurized diesel oil is a hydrocarbon oil that contains a large amount of basic nitrogen (especially anilines). By adding desulfurized diesel oil directly to straight run diesel oil, it is easy to make hydrocarbon oil suitable as the first hydrocarbon oil. Can be prepared.

  In the said aspect, the desulfurization oil which can be applied suitably as a light oil can be manufactured in a 1st process by using the hydrocarbon oil which added the desulfurization light oil directly to the straight run light oil. That is, in the said aspect, while suppressing catalyst deterioration in a 2nd process, the direct desulfurization light oil conventionally used as a heavy oil base material can be used as a raw material of light oil. For this reason, according to the said aspect, the manufacturing process of light oil can be implemented with high efficiency.

  In addition, the first step according to the above aspect is easily performed by, for example, adding desulfurized gas oil directly to the raw material oil in a production process for obtaining light oil by desulfurizing a conventional raw material oil (straight-run gas oil). be able to. According to this, the efficiency improvement of the manufacturing process of the existing light oil can be achieved.

  When the hydrocarbon oil obtained by adding desulfurized gas oil directly to straight-run gas oil is used as the first hydrocarbon oil, the amount of direct desulfurized gas oil added is appropriately determined so as to satisfy the above-mentioned preferred basic nitrogen content ratio range. Can be adjusted. The addition amount of the direct desulfurized gas oil can be, for example, 5 to 50 parts by mass, preferably 10 to 30 parts by mass, and more preferably 15 to 20 parts by mass with respect to 100 parts by mass of the straight-run gas oil. Part.

(Second step)
The second step is a step of bringing the second hydrocarbon oil into contact with the hydrorefining catalyst that has passed through the first step. In the second step, low density coke is formed in the vicinity of the active species of the hydrotreating catalyst in the first step. Is sufficiently suppressed.

  The second hydrocarbon oil is not particularly limited as long as it includes the other part of the hydrocarbon oil in which the graphite lattice image is observed by the evaluation method described above. For example, the second hydrocarbon oil is It may have the following properties.

  The second hydrocarbon oil may contain, for example, a sulfur content and an aromatic content. The content ratio of the aromatic component in the second hydrocarbon oil may be, for example, 30% by volume or more with respect to the total amount of the second hydrocarbon oil. Is preferably 33% by volume or more.

  In addition, the aromatic content in the second hydrocarbon oil is preferably 70% by volume or less, and more preferably 50% by volume or less. When the content ratio of the aromatic component in the second hydrocarbon oil is too high, there is a tendency that a problem of catalyst deterioration due to generation of coke occurs. That is, the effect that excessive coke production | generation can be suppressed is show | played by making the content rate of the aromatic component in a 2nd hydrocarbon oil below into the said upper limit.

  The second hydrocarbon oil may contain at least one bicyclic aromatic component selected from the group consisting of naphthalenes and biphenyls as the aromatic component. These bicyclic aromatic components are likely to form the above-mentioned high-density coke, and when a hydrocarbon oil containing such bicyclic aromatic components is applied to a conventional production process, the rate of catalyst deterioration is significantly improved. There was a problem. On the other hand, in the desulfurization method according to the present embodiment, as described above, low-density coke is formed in the vicinity of the catalytically active species in the first step in advance. Even if it contains a group, catalyst deterioration is sufficiently suppressed.

  In the present specification, naphthalene refers to naphthalene or a compound having a structure in which one or more hydrogen atoms of naphthalene are substituted with a substituent. Biphenyls refer to biphenyl or a compound having a structure in which one or more hydrogen atoms of biphenyl are substituted with substituents. As said substituent in naphthalenes and biphenyls, a C1-C8 alkyl group is mentioned, for example. Specific examples include 1-methylnaphthalene, 1-ethylnaphthalene, 2,3-dimethylnaphthalene, 1,4-dimethylnaphthalene, 2,6-dimethylnaphthalene, 1-propylnaphthalene, 1,2,6-trimethylnaphthalene, , 4,5-trimethylnaphthalene, 1-butylnaphthalene, 1,2,3,4-tetramethylnaphthalene, 2-methylbiphenyl, 4-methylbiphenyl, 2,2'-dimethylbiphenyl, 4,4'-dimethylbiphenyl 2-ethylbiphenyl, 2-propylbiphenyl, 2,4,6-trimethylbiphenyl, 2-butylbiphenyl, 2,2′-diethylbiphenyl, and the like.

  The content ratio of the bicyclic aromatic component in the second hydrocarbon oil may be 10% by volume or more, or 12% by volume or more with respect to the total amount of the second hydrocarbon oil.

  The content ratio of the bicyclic aromatic component in the second hydrocarbon oil is preferably 20% by volume or less and more preferably 15% by volume or less with respect to the total amount of the second hydrocarbon oil. . When the content ratio of the above-mentioned bicyclic aromatic component in the second hydrocarbon oil is too high, there is a tendency that a problem of catalyst deterioration due to generation of coke occurs. That is, the effect that excessive coke production | generation can be suppressed is show | played by making the content rate of the said 2 ring aromatic content in a 2nd hydrocarbon oil below into the said upper limit.

  The second hydrocarbon oil may contain a component other than the above-mentioned bicyclic aromatic component as an aromatic component. For example, the second hydrocarbon oil may contain a monocyclic aromatic component, a tricyclic or higher polycyclic aromatic component, and the like. The monocyclic aromatic component is a compound having one benzene ring in the molecule, and examples thereof include tetralin and indane. Examples of the tricyclic or higher polycyclic aromatic component include phenanthrene, anthracene, pyrene, chrysene and the like.

  The content ratio of the sulfur content in the second hydrocarbon oil may be, for example, 0.5% by mass or more and 0.8% by mass or more with respect to the total amount of the second hydrocarbon oil. Further, the content ratio of the sulfur content in the second hydrocarbon oil is preferably 2.0% by mass or less, more preferably 1.5% by mass or less, with respect to the total amount of the second hydrocarbon oil. . If the sulfur content is high, the catalyst life tends to be short. In addition, if the sulfur content is low, it is necessary to use an expensive hydrocarbon oil having a low sulfur content, which is not economical.

  The second hydrocarbon oil may contain a nitrogen content. The content ratio of the nitrogen content in the second hydrocarbon oil may be, for example, 50 mass ppm or more with respect to the total amount of the second hydrocarbon oil, or may be 60 mass ppm or more. Moreover, the content rate of the nitrogen content in a 2nd hydrocarbon oil may be 300 mass ppm or less with respect to the whole quantity of a 2nd hydrocarbon oil, for example, and may be 200 mass ppm or less. If the nitrogen content is high, the catalyst life tends to be short. Moreover, since the influence of the catalyst poisoning by nitrogen is small when the content rate of nitrogen content is low, the initial catalytic activity tends to be high.

  The second hydrocarbon oil may contain a basic nitrogen content. The content ratio of the basic nitrogen content in the second hydrocarbon oil is preferably lower than the content ratio of the basic nitrogen content in the first hydrocarbon oil, for example, 50% relative to the total amount of the second hydrocarbon oil. It may be not more than mass ppm and may be not more than 45 mass ppm. Moreover, the content rate of the basic nitrogen content in the second hydrocarbon oil may be 10 mass ppm or more with respect to the total amount of the second hydrocarbon oil, and may be 30 mass ppm or more.

For example, the second hydrocarbon oil may have a density at 15 ° C. of 0.83 to 0.89 g / cm ³ . The density of the second hydrocarbon oil at 15 ° C. is preferably 0.83 to 0.88 g / cm ³ , more preferably 0.84 to 0.87 g / cm ³ , and still more preferably 0. .86 to 0.87 g / cm ³ . When the density of the second hydrocarbon oil is within the above range, an effect of improving the fuel efficiency of the product light oil is exhibited.

  For example, the second hydrocarbon oil may have a 90% by volume distillation temperature of 320 to 370 ° C. The 90 vol% distillation temperature of the second hydrocarbon oil is preferably 320 to 360 ° C, more preferably 330 to 355 ° C. When the 90 volume% distillation temperature of the second hydrocarbon oil is within the above range, an effect of suppressing PM of the product gas oil is exhibited.

  The second hydrocarbon oil may have a 10% by volume distillation temperature of 200 to 280 ° C, for example. The 10 vol% distillation temperature of the second hydrocarbon oil is preferably 210 to 255 ° C, more preferably 220 to 270 ° C. When the 10% by volume distillation temperature of the second hydrocarbon oil is within the above range, the effect that the oxidation stability of the product gas oil is high is exhibited.

  In the second step, the desulfurization reaction is performed by bringing the second hydrocarbon oil into contact with the hydrorefining catalyst. For this reason, in the second step, the second hydrocarbon oil is preferably brought into contact with the hydrorefining catalyst in the presence of hydrogen.

Various known conditions can be applied to the desulfurization reaction conditions. In the second step, the hydrogen partial pressure can be set to, for example, 1 to 10 MPa, and preferably 3 to 8 MPa. Moreover, LHSV can be 0.1-5 h < ^-1 >, for example, Preferably it is 0.5-3 h < ^-1 >. Moreover, hydrogen oil ratio can be 30-500 NL / L, for example, Preferably it is 60-300 NL / L. Moreover, reaction temperature can be 250-420 degreeC, for example, Preferably it is 270-400 degreeC.

  The conditions for the desulfurization reaction in the second step can be appropriately changed according to the properties of the second hydrocarbon oil, the properties of the desired desulfurized oil, and the like. In addition, when the second hydrocarbon oil is desulfurized in the second step, the second carbonization after contacting the hydrorefining catalyst in the second step in order to satisfy the sulfur content regulation in the product gas oil. It is preferable to operate so that the sulfur content of hydrogen oil (second product oil) is 7 to 15 ppm by mass. Furthermore, you may drive | operate so that the content rate of the sulfur content of the said production oil may be 7-10 mass ppm. When desulfurized at less than 7 mass pppm, the catalyst tends to deteriorate. On the other hand, when it exceeds 15 mass ppm, it may become impossible to satisfy the sulfur content regulation of the product light oil. The operation period of the second step is preferably 10 days or longer, more preferably 20 days or longer. By extending this period, the period which processes low quality raw material oil becomes long, and the economical efficiency of a light oil manufacturing process improves.

  The second hydrocarbon oil may include, for example, a hydrocarbon oil derived from crude oil. For example, straight-run gas oil (LGO), catalytic cracked gas oil (LCO) obtained from crude oil, and hydrorefined products such as atmospheric distillation residual oil, vacuum distillation residual oil, vacuum gas oil, and solvent debris oil can be used. .

  The straight-run gas oil refers to a gas oil fraction obtained by subjecting crude oil to atmospheric distillation.

  Examples of the catalytic cracking gas oil include a gas oil fraction obtained by catalytic cracking of atmospheric distillation residual oil, vacuum gas oil, solvent-depleted oil, or hydrorefined oil thereof using a fluid catalytic cracking apparatus.

  Examples of the hydrorefined product include a direct desulfurized gas oil (RDS-GO) obtained by hydrorefining atmospheric distillation residue, an indirect desulfurized gas oil obtained by hydrotreating a vacuum distillation residue, and a vacuum gas oil. And hydrorefined oil of reduced pressure gas oil obtained by hydrorefining, and hydrorefined oil of solvent devolatilized oil obtained by hydrotreating solvent devolatilized oil (DAO).

  The second hydrocarbon oil may be prepared, for example, by adding an aromatic component to a hydrocarbon oil that does not contain an aromatic component or has a low aromatic content. The second hydrocarbon oil is prepared by adding a hydrocarbon oil containing a large amount of aromatic content to a hydrocarbon oil containing no aromatic content or a low content of aromatic content. Also good.

  In one aspect, as the second hydrocarbon oil, a hydrocarbon oil obtained by adding a catalytic cracked light oil to a straight-run gas oil can be suitably used. Catalytic cracking gas oil is a hydrocarbon oil that contains a large amount of aromatics (especially bicyclic aromatics), and is suitable as a second hydrocarbon oil by adding catalytic cracking gas oil to straight-run gas oil. Oil can be easily prepared.

  In the said aspect, the catalytic cracking light oil conventionally used as a heavy oil base material can be used suitably as a raw material of light oil by using the hydrocarbon oil which added the catalytic cracking light oil to the straight run light oil.

  In addition, the second step according to the above embodiment is easily performed by adding catalytic cracking gas oil to the feedstock oil in a production process for obtaining gas oil by desulfurizing a conventional feedstock oil (straight-run gas oil), for example. Can do. According to this, the efficiency improvement of the manufacturing process of the existing light oil can be achieved.

  When the hydrocarbon oil obtained by adding catalytic cracking gas oil to straight-run gas oil is used as the second hydrocarbon oil, the amount of catalytic cracking gas oil added is adjusted as appropriate so as to satisfy the above-mentioned preferred aromatic content ratio range. can do. The amount of catalytically cracked gas oil added is, for example, 5 to 50 parts by mass, preferably 10 to 30 parts by mass, and more preferably 15 to 20 parts by mass with respect to 100 parts by mass of straight-run gas oil. Part.

  In the desulfurization method according to the present embodiment, the first step may be a step that is performed only once before the second step. In the desulfurization method according to this embodiment, the first step may be performed again after the second step. Furthermore, in the desulfurization method according to the present embodiment, the first step and the second step may be alternately repeated.

  In the second step, although the catalyst deterioration is suppressed as described above, the catalyst activity gradually decreases with time. By performing the first step again after the second step, the reduced catalyst activity tends to recover. That is, by alternately performing the first step and the second step, the hydrocarbon oil can be desulfurized while maintaining good catalytic activity for a long period of time.

  The reason why the above effect is achieved is not necessarily clear, but in the second step, the low density coke was gradually peeled off, and instead the high density coke was deposited and the catalytic activity was reduced. This is probably because the high-density coke is peeled off in the first step, and low-density coke is formed again on the surface of the catalyst carrier after peeling.

  As mentioned above, although the desulfurization method concerning this embodiment was demonstrated, this invention is not limited to the said embodiment.

  For example, another aspect of the present invention may be a method for producing a desulfurized oil in which a hydrocarbon oil is desulfurized by the above desulfurization method to obtain a desulfurized oil. According to the production method, even if the hydrocarbon oil of the raw material oil contains an aromatic component, desulfurization can be efficiently obtained while suppressing catalyst deterioration.

  Still another aspect of the present invention may be a method for suppressing the decrease in the activity of the hydrotreating catalyst. One aspect of the suppression method is a method of suppressing a decrease in catalyst activity in a desulfurization step of desulfurizing the hydrocarbon oil by bringing a hydrocarbon oil containing a sulfur content and an aromatic content into contact with a hydrorefining catalyst. And before the desulfurization step, a hydrocarbon oil having a higher content ratio of basic nitrogen than the hydrocarbon oil and a lower content ratio of aromatic content is brought into contact with the hydrorefining catalyst. It is what. According to such a suppression method, it is possible to suppress degradation of the hydrorefining catalyst in the desulfurization step of desulfurizing the hydrocarbon oil containing the aromatic component.

  Moreover, the desulfurized oil desulfurized by the desulfurization method can be suitably used as a light oil base material. That is, it can be said that one aspect of the present invention relates to a light oil base material containing the desulfurized oil desulfurized by the desulfurization method, and another aspect of the present invention includes a step of obtaining desulfurized oil by the desulfurization method. It can be said that it is a method for producing a light oil base.

  The hydrocarbon oil desulfurization method according to the second embodiment includes a step of bringing the other part of the hydrocarbon oil, in which no graphite lattice image is observed, into contact with the hydrorefining catalyst in the evaluation method described above. That is, the hydrocarbon oil is a hydrocarbon oil with a slow degradation rate of the hydrotreating catalyst.

  Such a hydrocarbon oil desulfurization method is not particularly limited, and a known desulfurization method can be adopted. However, from the viewpoint of further suppressing the deterioration rate of the hydrorefining catalyst, the first embodiment described above is used. A hydrocarbon oil desulfurization method can also be employed.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples.

<Preparation of hydrotreating catalyst>
(Catalyst A)
On the alumina-silica-phosphorus oxide carrier, Co is supported so that the amount of Co is 2.4% by mass in terms of metal element and Mo is 15.0% by mass in terms of metal element, based on the total amount of catalyst. Yielded catalyst A with 210 m ² / g.

(Catalyst B)
On an alumina-silica-titania carrier, Co is supported to 2.4 mass% in terms of metal element and Mo is 15.0 mass% in terms of metal element, based on the total amount of catalyst, and the BET specific surface area is 230 m. Catalyst B which was ² / g was obtained.

<Preparation of crude oil-derived hydrocarbon oil>
Prepare straight run diesel oil A, straight run diesel oil B, catalytic cracking diesel oil A, and direct desulfurized diesel oil A obtained by processing Middle Eastern crude oil shown in Table 2, and mix each hydrocarbon oil as shown in Table 3. Mixed light oils A to E shown in Table 3 were prepared by mixing at a ratio (mass ratio).

In this example, the distillation properties, density, sulfur content, and nitrogen content are obtained as follows.
Distillation properties: those obtained by “petroleum product-distillation test method” defined in JIS K 2254.
Density: The density at 15 ° C. is measured in accordance with “Oscillating Density Test Method” of “Crude Oil and Petroleum Products—Density Test Method and Density / Mass / Capacity Conversion Table (Excerpt)” prescribed in JIS K 2249. Is.
Sulfur content: Measured according to “Radiation Excitation Method” of “Crude Oil and Petroleum Products—Sulfur Content Test Method” defined in JIS K2541-1992.
Nitrogen content: Measured according to JIS K 2609 “Crude oil and petroleum products—Test method for nitrogen content”.
Basic nitrogen content: UOP test method no. It is measured according to 269-90.
Total aromatics and bicyclic aromatics: Measured according to Petroleum Institute test method JPI-5S-49-2007 “Petroleum products—Hydrocarbon type test method—High performance liquid chromatograph method”.

  Further, the concentration of anilines (ppm by mass) and the ratio of anilines (%) in the basic nitrogen-containing compound were determined using a two-dimensional GC system (KT2006 (GC and GC) manufactured by ZOEX) having the same configuration as that shown in FIG. The detector was obtained by the same procedure as the flow chart shown in FIG.

(Examples 1-5)
<Hydrohydrocarbon refining (contact process)>
Using the mixed light oils A to E shown in Table 3 as raw material oils, adjusting the reaction temperature within the following range with the product oil sulfur content shown in Table 4 as the target, hydrotreating with the following hydrotreating catalyst amounts and operating conditions (Desulfurization).
Hydrotreating catalyst amount: 100 mL
Reaction temperature: 340-380 ° C
LHSV: 1.0 h ⁻¹
Hydrogen partial pressure: 5.5 MPa
Hydrogen / oil ratio: 200NL / L

<Catalyst heat treatment (heat treatment step)>
The catalyst obtained by hydrotreating each of the raw oils (mixed light oils A to E) under the above conditions is withdrawn from the reactor, and from a room temperature to a predetermined heat treatment temperature (° C.) described in Table 4 under a nitrogen atmosphere. After the temperature is increased at a predetermined heat treatment temperature increase rate (° C./min), a predetermined heat treatment time (hour) is maintained at a predetermined heat treatment temperature (° C.). Each catalyst was heat-treated under the condition of cooling at a heat treatment cooling rate (° C./min).

<TEM observation of heat treatment catalyst (observation process)>
About the catalyst heat-processed on the said conditions, TEM observation was performed on the following conditions, and the presence or absence of the graphite lattice image was confirmed.
(Preprocessing)
The surface layer of the catalyst was cut out using a focused ion beam, and a thin sample for TEM observation having a thickness of about 100 nm was obtained.
Ion source: Ga
Accelerating voltage: rough machining 40kV, finishing 10kV
Deposit: Pt

(TEM observation)
About the sample obtained by the said pre-processing, the TEM photograph of the catalyst was image | photographed on condition of the following using TEM.
Electron gun: LaB6
Accelerating voltage: 200kV
Shooting magnification: 1.5 million times

The TEM observation results in Examples 1 and 3 are shown in FIGS. In addition, the part enclosed with the white circle in FIG. 5 is a part by which the graphite lattice image was recognized. An enlarged view of FIG. 5 is shown in FIG. When a lattice image is observed in the obtained photograph, the distance between the planes is measured, and when the plane distance of the (002) plane of graphite is about 0.35 nm, it is determined that the catalyst has graphite.
The intensity profile of the lattice image was measured in the direction perpendicular to the crystal plane of the observed lattice image (FIG. 7), three consecutive peaks observed in the intensity profile were extracted, and the distance between the peaks at both ends (A in FIG. 7) was measured, and the numerical value divided by 2 was defined as the surface interval. The results are shown in Table 4.

  No graphite lattice image was observed for mixed light oil A and mixed light oil B, but a graphite lattice image was observed for mixed light oil C, mixed light oil D, and mixed light oil E.

(Examples 6 to 10, Comparative Examples 1 to 3)
<Hydrorefining of hydrocarbon oil>
For the mixed light oils A to E shown in Table 3, the reaction temperature was adjusted in the following range with the product oil sulfur content shown in Tables 5 and 6 as a target, and the following hydrotreatment catalyst amounts and operating conditions were used. The hydrorefining (desulfurization) described in 6. The deterioration rates of the catalyst at that time are also shown in Tables 5 and 6.
Hydrotreating catalyst amount: 100 mL
Reaction temperature: 340-380 ° C
LHSV: 1.0 h ⁻¹
Hydrogen partial pressure: 5.5 MPa
Hydrogen / oil ratio: 200NL / L

<Calculation of degradation rate of hydrorefining catalyst>
Obtaining the relationship between the reaction time and the reaction temperature necessary to make the sulfur content in the gas oil fraction (desulfurized gas oil) after treatment 8 ppm by mass, the required reaction temperature on the first operation period and the required reaction on the last day The degradation rate (° C./day) of the hydrorefining catalyst was calculated by dividing the temperature difference by the operation period. The results are shown in Tables 5 and 6.

  As described in Examples 1 to 5 above, the mixed light oil A and the mixed light oil B are unlikely to deteriorate the hydrorefining catalyst, and the mixed light oil C, the mixed light oil D, and the mixed light oil E are likely to deteriorate the hydrorefining catalyst. It was judged. From the results of the catalyst deterioration rates (° C./day) of Examples 6 and 7 and Comparative Examples 1 to 3, it can be seen that this determination is correct.

  In addition, after contacting the hydrorefining catalyst with the mixed light oil A or B that was determined to be difficult to degrade as the first hydrocarbon oil, it was determined that the catalyst was likely to be degraded as the second hydrocarbon oil. It can be seen that in Examples 8 to 10 in which the mixed light oil C or D was brought into contact with the hydrorefining catalyst, deterioration of the hydrorefining catalyst was suppressed, and the operation period could be significantly increased.

  DESCRIPTION OF SYMBOLS 10 ... Sample introduction part, 12 ... 1st column, 14 ... Modulation column, 15 ... Heating part, 16 ... Cooling part, 18 ... 2nd column, 20 ... Splitter, 22 ... Flame ionization detector (FID), 24 ... Chemiluminescent nitrogen detector (NCD), 30 ... mass spectrometer (MS), 50 ... modulator part, 100 ... comprehensive two-dimensional GC system.

Claims (8)

A method for evaluating a hydrocarbon oil to be subjected to a desulfurization reaction,
Contacting a part of the hydrocarbon oil with a hydrorefining catalyst;
A heat treatment step of heat treating the hydrorefining catalyst that has undergone the contact step;
An observation step of observing the heat-treated hydrorefined catalyst with a transmission electron microscope to observe the presence or absence of a graphite lattice image. A first step of contacting the first hydrocarbon oil with a hydrorefining catalyst;
A second step of bringing a second hydrocarbon oil into contact with the hydrorefining catalyst that has undergone the first step,
The second hydrocarbon oil includes the other part of the hydrocarbon oil in which a graphite lattice image is observed by the evaluation method according to claim 1,
The first hydrocarbon oil contains a basic nitrogen content,
The basic nitrogen content in the first hydrocarbon oil is higher than the basic nitrogen content in the second hydrocarbon oil,
The aromatic content in the first hydrocarbon oil is lower than the aromatic content in the second hydrocarbon oil,
Desulfurization method for hydrocarbon oil.   The hydrocarbon oil desulfurization method according to claim 2, wherein the basic nitrogen content includes anilines.   The method for desulfurizing a hydrocarbon oil according to claim 2 or 3, wherein the aromatic component includes at least one bicyclic aromatic component selected from the group consisting of naphthalenes and biphenyls.   The method for desulfurizing a hydrocarbon oil according to any one of claims 2 to 4, wherein the first hydrocarbon oil includes a directly desulfurized gas oil.   The hydrocarbon oil desulfurization method according to any one of claims 2 to 5, wherein the first step and the second step are alternately performed a plurality of times.   The manufacturing method of desulfurized oil which obtains desulfurized oil with the desulfurization method of hydrocarbon oil as described in any one of Claims 2-6.   A method for producing desulfurized oil, comprising the step of bringing the other part of the hydrocarbon oil, in which no graphite lattice image is observed, into contact with a hydrorefining catalyst in the evaluation method according to claim 1.