JP2012148215A - Regeneration method for hydrotreatment catalyst for hydrocarbon oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a regeneration method capable of sufficiently recovering desulfurization activity of a used hydrotreatment catalyst.SOLUTION: The regeneration method for the used hydrotreatment catalyst for hydrocarbon oil includes: an oil removing process of subjecting oil removing treatment to the used hydrotreatment catalyst supporting group 6 metals in the periodic table, group 8 metals in the periodic table and phosphorus, whose activity is lowered by being used in the hydrotreatment of the hydrocarbon oil; a firing process of firing the hydrotreatment catalyst after the oil removing process at 300-600°C; a supporting process for making a fired material obtained by the firing process support organic acid and phosphorus so that the molar ratio of [organic acid]/[group 8 metals in the periodic table] is 0.6-1 and the molar ratio of [phosphorus excluding the phosphorus contained in the fired material after the firing process and before the supporting process (as PO)]/[group 6 metals in the periodic table] is 0.05-0.3; and a drying process of drying the fired material after the supporting process at or below 200°C.

Description

  The present invention relates to a method for regenerating a spent hydrotreating catalyst having a reduced activity used for hydrotreating a hydrocarbon oil. More specifically, the present invention relates to a method for regenerating a spent hydroprocessing catalyst to a level equivalent to that of a non-used hydroprocessing catalyst having a desulfurization activity superior to that of a hydroprocessing catalyst regenerated by a conventional method.

  In recent years, quality control values for petroleum products tend to be stricter worldwide in order to improve the air environment. In particular, the sulfur content in light oil affects the durability of post-treatment devices such as nitrogen oxide (NOx) reduction catalysts and continuous regeneration diesel exhaust particulate removal filters that are expected as a countermeasure for exhaust gas. Reduction of sulfur compounds is required.

Under such circumstances, hydrotreating catalysts having excellent desulfurization activity have been developed that can achieve ultra-deep desulfurization of hydrocarbon oils without severe operating conditions.
When the hydrotreating catalyst is used for a certain period of time, the carbonaceous matter is deposited on the surface of the catalyst and the activity is lowered. For this reason, it is urgent to develop a method for regenerating a hydroprocessing catalyst that can be regenerated so that its excellent desulfurization activity is fully restored and used in commercial equipment multiple times. It has become a challenge.

  In recent years, many studies have been made on a method for regenerating a desulfurization catalyst. For example, as a method for regenerating an excellent used hydroprocessing catalyst, a method has been proposed in which the oil in the used catalyst is removed and calcined, and then a predetermined amount of organic matter is supported on the catalyst and dried. . (See Patent Document 1). This method can be said to be a useful method in that a predetermined performance can be easily obtained as a method for restoring the activity of the deactivated spent catalyst.

JP 2008-290071 A

  Under the current situation where environmental policies such as waste reduction are important, the activity after regeneration of the used catalyst is further improved, and the physical properties of the catalyst are almost the same as those of the new catalyst without much impact on the catalyst properties after regeneration. There is an urgent need to develop a regeneration method that can be maintained.

  In view of the above-described conventional situation, the object of the present invention is to further improve the desulfurization activity of the regenerated catalyst and to maintain substantially the same catalyst physical properties as the new catalyst after the regeneration. The present invention provides a method for regenerating a spent hydroprocessing catalyst.

As a result of intensive studies to achieve the above object, the inventors of the present invention calcined a used hydroprocessing catalyst to remove carbonaceous matter on the catalyst, and then obtained organic acid and phosphorus were added to the obtained calcined product. [Organic acid] / [Group 8 metal] (molar ratio), [P ₂ O ₅ ] / [Group 6 metal] (molar ratio) in a specific range Thus, the present invention has been completed by finding a regeneration method capable of improving the desulfurization active region to substantially the same as that of the unused catalyst while maintaining the same physical properties as those of the unused catalyst.

That is, the present invention relates to a hydrotreating catalyst carrying a spent periodic group 6 metal, a periodic table group 8 metal, and phosphorus, which has been used for hydrotreating hydrocarbon oil and has decreased activity. An oil removal step for removing oil,
A calcining step of calcining the hydrotreating catalyst after the oil removal step at 300 to 600 ° C .;
In the fired product obtained by the firing step, an organic acid and phosphorus, [organic acid] / [group 8 metal of the periodic table] molar ratio is 0.6 to 1, and [supporting step after the firing step] Supporting so that the molar ratio of phosphorus excluding phosphorus contained in the previous fired product (in terms of P ₂ O ₅ ) / [Group 6 metal of the periodic table] is 0.05 to 0.3 Process,
And a method for regenerating a used hydrocarbon oil hydrotreating catalyst, comprising a drying step of drying the calcined product after the supporting step at 200 ° C. or lower.

  According to the regeneration method of the present invention, the desulfurization activity of the spent hydrocarbon oil hydrotreating catalyst can be more fully restored, and thus the present invention provides a hydrogen of hydrocarbon oil having further excellent desulfurization activity. A chemical conversion catalyst can be provided. Moreover, if the regenerated hydrotreating catalyst is used, sulfur compounds in hydrocarbon oil can be highly desulfurized under almost the same operating conditions as the new catalyst without requiring severe operating conditions.

The catalyst regeneration method of the present invention is a use in which a metal of Group 6 of the periodic table, a metal of Group 8 of the periodic table, and phosphorus are supported, and used for hydrotreating hydrocarbon oil. A method for regenerating a spent hydrotreating catalyst, comprising the following steps.
Oil removal treatment is performed on a hydrotreating catalyst loaded with a periodic group 6 metal, a periodic group 8 metal, and phosphorus, which has been used for hydrotreating a hydrocarbon oil, and which has been used. Oil removal process,
A calcining step of calcining the hydrotreating catalyst after the oil removal step at 300 to 600 ° C .;
In the fired product obtained by the firing step, an organic acid and phosphorus, [organic acid] / [group 8 metal of the periodic table] molar ratio is 0.6 to 1, and [supporting step after the firing step] Supporting so that the molar ratio of phosphorus excluding phosphorus contained in the previous fired product (in terms of P ₂ O ₅ ) / [Group 6 metal of the periodic table] is 0.05 to 0.3 Process,
And a drying step of drying the fired product after the supporting step at 200 ° C. or lower.

  In the present invention, any hydrotreating catalyst used in the hydrotreating of hydrocarbon oil in which the support is loaded with a group 6 metal of the periodic table, a group 8 metal of the periodic table, and phosphorus. It is possible to regenerate various used hydroprocessing catalysts that are manufactured by various manufacturing methods and used for hydroprocessing various hydrocarbon oils, regardless of their origin or use. it can.

  In the present invention, “Group 6 metal of the periodic table” means a Group 6A metal in the long periodic table, and “Group 8 metal of the periodic table” means in the long periodic table. It means a Group 8 metal ("Chemical Dictionary", 1st edition, 3rd edition, Tokyo Chemical Co., Ltd., April 1, 1994, p. 1079-1081).

The hydrotreating catalyst to be regenerated in the present invention is preferably a catalyst in which a group 6 metal of the periodic table, a group 8 metal of the periodic table, and phosphorus are supported on an inorganic oxide support.
Various inorganic oxides can be used as the inorganic oxide support in the hydrotreating catalyst, but an inorganic oxide whose main component is alumina is preferable.

As the alumina used for the carrier, various aluminas such as α-alumina, γ-alumina, δ-alumina, and alumina hydrate can be used, and porous and high specific surface area alumina is preferable. Alumina is suitable. The purity of alumina is about 98% by mass or more, preferably about 99% by mass or more. Examples of the impurities in alumina include SO ₄ ²⁻ , Cl ⁻ , Fe ₂ O ₃ , Na ₂ O and the like. These impurities are desirably as small as possible, and the total amount of impurities is 2% by mass or less, preferably 1 It is preferable that SO ₄ ^{2 −} <1.5% by mass, Cl ⁻ , Fe ₂ O ₃ , and Na ₂ O <0.1% by mass for each component.

  It is preferable to add another oxide component to the alumina used for the carrier, and the other oxide component is preferably one or more selected from zeolite, boria, silica and zirconia. By compounding these, it is advantageous to laminate molybdenum disulfide that forms desulfurization active sites. Among these, the zeolite preferably has an average particle diameter of 2.5 to 6 μm, more preferably 3 to 4 μm, as measured by a coal counter method (1 mass% NaCl aqueous solution, aperture 30 μm, ultrasonic treatment 3 minutes). It is. In addition, it is desirable that the zeolite has a particle size of 6 μm or less with respect to all the zeolite particles, about 70 to 98%, preferably about 75 to 98%, more preferably about 80 to 98%.

  Further, the inorganic oxide carrier in the hydrotreating catalyst may contain a phosphorus oxide. The method of incorporating the phosphorus oxide into the inorganic oxide support is not particularly limited and can be performed by an equilibrium adsorption method, a coprecipitation method, a kneading method, or the like, but a catalyst having a high desulfurization activity can be obtained. It is preferable to use a kneading method in which a raw material of phosphorous oxide is kneaded in alumina hydrate as a raw material of the carrier.

  In the hydrotreating catalyst, the Group 6 metal supported on the carrier is preferably molybdenum or tungsten, and more preferably molybdenum. The supported amount of Group 6 metal is preferably 10 to 40% by mass, more preferably 10 to 30% by mass in terms of catalyst and oxide. If it is 10 mass% or more, it is sufficient for expressing the effects attributable to the Group 6 metal, and it is preferable. Moreover, if it is 40 mass% or less, the group 6 metal compound does not aggregate in the impregnation (support) step of the group 6 metal, the dispersibility of the group 6 metal is improved, and the group 6 metal that is dispersed efficiently The catalyst activity is improved because it does not exceed the supported amount limit and the surface area of the catalyst is not significantly reduced.

In the hydrotreating catalyst, the group 8 metal supported on the carrier is preferably cobalt or nickel. The supported amount of the group 8 metal is preferably 1 to 15% by mass, more preferably 3 to 8% by mass in terms of catalyst and oxide. If it is 1 mass% or more, the active point which belongs to a group 8 metal is fully obtained, and it is preferable. Further, if it is 15% by mass or less, the group 8 metal compound is not aggregated in the step of containing (supporting) the group 8 metal, the dispersibility of the group 8 metal is improved, and inactive cobalt and nickel species Co ₈ S species such as Co ₉ S, which is a group 8 metal species such as Ni ₃ S ₂ species, CoO species, NiO species, etc., Co spinel species incorporated into the support lattice, Ni spinel species, etc. are generated. Therefore, it is preferable that the catalytic ability is improved. When cobalt and nickel are used as the group 8 metal, the molar ratio of [Co] / [Ni + Co] is in the range of 0.6 to 1, more preferably in the range of 0.7 to 1. It is desirable to do. When this ratio is 0.6 or more, a coke precursor is not formed on Ni, and the catalytic active sites are not covered with coke, and as a result, the activity does not decrease.

In the above-described contents of the Group 8 metal and the Group 6 metal, the optimum mass ratio of the Group 8 metal to the Group 6 metal is preferably [group 8 metal] / [group 8 metal + group 6 metal] in terms of oxide. The value is 0.1 to 0.25. If this value is 0.1 or more, the generation of CoMoS structure, NiMoS structure and the like, which are considered to be desulfurization active points, is not suppressed, and the degree of desulfurization activity improvement is increased, which is preferable. If it is 0.25 or less, the production of the above-described inert cobalt, nickel species (Co ₉ S ₈ species, Ni ₃ S ₂ species, etc.) is suppressed, and the catalytic activity is improved, which is preferable.

  In addition, the carrying | support of the carrying | support component of a 6th group metal, a 8th group metal, and phosphorus to an inorganic oxide support | carrier generally prepares the impregnation solution containing the raw material compound containing these carrying | support components, and is obtained. It is carried out by an impregnation method in which the support is impregnated so that the supported amount of the catalyst support component falls within a desired range.

  For example, examples of the raw material compound containing a Group 6 metal used for supporting a Group 6 metal include molybdenum trioxide, molybdophosphoric acid, ammonium molybdate, and molybdic acid. Examples of the raw material compound containing a group 8 metal used for supporting a group 8 metal include cobalt carbonate, nickel carbonate, cobalt nitrate hexahydrate, nickel nitrate hexahydrate, and the like. Furthermore, examples of the raw material compound containing phosphorus used for supporting phosphorus include phosphoric acid compounds such as orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, and tetraphosphoric acid.

  In addition, the hydrotreating catalyst to be regenerated in the present invention carries a component other than the Group 6 metal of the periodic table, the Group 8 metal of the periodic table, and phosphorus, such as organic acid or carbon derived from organic substances, on the support. It may be a catalyst. As the hydrotreating catalyst, for example, a catalyst in which an organic acid or carbon derived from an organic substance is supported in addition to a group 6 metal of a periodic table, a group 8 metal of a periodic table, and phosphorus on an inorganic oxide support containing zeolite. Etc. More specifically, there is a catalyst in which citric acid or citric acid-derived carbon is supported in addition to a periodic table group 6 metal, a periodic table group 8 metal, and phosphorus on an inorganic oxide support containing zeolite. It is done.

In the present invention, it is possible to suitably perform regeneration of the used catalyst after using the above-described hydrotreating catalyst for hydrotreating hydrocarbon oil such as light oil.
Hereafter, each process of the regeneration method of the catalyst of this invention is demonstrated in detail.

  In the present invention, first, a used catalyst is subjected to oil removal treatment (oil removal step). In general, nitrogen, water vapor, carbon dioxide, air, or the like can be used for this oil removal treatment. For example, when volatile components such as oil on the surface of the used catalyst are removed by contacting the used catalyst with heated air at 300 to 400 ° C., the oxygen concentration in the heated air is optimal depending on many processing conditions. Although the concentration is different, it is generally 21% by volume or less, preferably 20% by volume or less.

  In the present invention, the spent catalyst subjected to the oil removal treatment as described above is calcined at 300 to 600 ° C., preferably 400 to 500 ° C. (calcining step). Although the firing time depends on the firing temperature, it is generally 15 minutes to 10 hours, preferably 30 minutes to 9 hours. If the calcination temperature is less than 300 ° C., the carbon content cannot be sufficiently removed by depositing on the catalyst, so that the activity cannot be sufficiently recovered. On the other hand, at a temperature higher than 600 ° C., the group 6 metal of the periodic table and the group 8 metal of the periodic table are sintered, so that the activity cannot be sufficiently recovered. Although depending on the calcination temperature, in general, if the calcination time is 15 minutes or more, it is possible to remove carbon deposited on the catalyst, and if it is 10 hours or less, the scale of equipment is expanded. Therefore, the necessary amount of catalyst regeneration can be performed.

  In the present invention, an organic acid and phosphorus are supported on a calcined product obtained by calcining a used catalyst that has been subjected to oil removal treatment as described above (that is, a calcined product obtained after the calcining step) (supporting step). ), And then dried at 200 ° C. or lower, preferably 80 to 200 ° C. (drying step).

  The organic catalyst is supported on the baked product of the spent catalyst by the molar ratio of the supported amount of the organic acid to the supported amount of the group 8 metal in the periodic table ([organic Acid] / [molar ratio of Group 8 metal of periodic table)] is 0.6 to 1, preferably 0.6 to 0.8.

  If the molar ratio of [organic acid] / [group 8 metal of the periodic table] is 0.6 or more, the group 8 metal sufficiently forms an organic acid and a complex compound on the catalyst surface. This is preferable because a desulfurization active site belonging to the Group 8 metal can be sufficiently obtained. Moreover, if the said molar ratio is 1 or less, a group 8 metal can fully form a complex compound with an organic acid on the catalyst surface, On the other hand, it suppresses that an excess organic acid forms a complex compound with a group 6 metal. It is preferable because it is considered that the

  Various organic substances such as polyhydric alcohols are generally used as the organic compound supported on the burned product of the used catalyst. In the present invention, an organic acid is particularly used. Organic acids are preferred in that they form water soluble complexes with Group 8 metals of the Periodic Table.

Examples of organic acids that can be used in the present invention include aliphatic polycarboxylic acids such as citric acid, malic acid, tartaric acid, oxalic acid, succinic acid, glutamic acid, gluconic acid, adipic acid, benzoic acid, phthalic acid, and isophthalic acid. Examples thereof include acid, salicylic acid, malonic acid and the like, and citric acid is particularly preferable in that it forms a very stable water-soluble complex with a group 8 metal ion of the periodic table.
These organic acids are preferably compounds that do not substantially contain sulfur. These organic acids can be used alone or in admixture of two or more as required.

In this invention, it is necessary to carry | support new phosphorus with the organic acid to the baked product of a used catalyst. Phosphorus loading is the molar ratio of the amount of phosphorus newly supported in terms of P ₂ O ₅ to the amount of Group 6 metal in the periodic table in the calcined product after the phosphorus is supported (the above-mentioned The molar ratio of phosphorus (in terms of P ₂ O ₅ ) / [group 6 metal of the periodic table) excluding phosphorus contained in the fired product before and after the firing process is 0.05 to 0.3. The amount is preferably in the range of 0.07 to 0.2, more preferably 0.1 to 0.2.

The molar ratio of the amount of phosphorus newly supported in the supporting step in terms of P ₂ O ₅ (hereinafter sometimes simply referred to as “P ₂ O ₅ converted amount”) to the Group 6 metal of the periodic table is as follows. If it is 0.05 or more, phosphorous that forms heteropolyacid on the catalyst surface and that does not form heteropolyacid is dispersed on the alumina surface, so highly dispersed and multilayer molybdenum disulfide crystals are formed in the preliminary sulfidation step. Therefore, it is presumed that desulfurization active sites can be sufficiently arranged. Further, if the molar ratio is 0.3 or less, the group 6 metal sufficiently forms a heteropolyacid on the catalyst surface, and phosphorus that does not form the heteropolyacid is dispersed on the alumina surface. It is presumed that no active desulfurization active sites are covered, and therefore, it is preferable because it does not cause a decrease in activity.

Further, phosphorus is supported on the calcined product of the spent catalyst so that the molar ratio of [P ₂ O ₅ equivalent] / [Group 6 metal of the periodic table] is in the range of 0.05 to 0.3. Thus, it is possible to suppress the deterioration of the side mechanical strength (SCS) of the catalyst after regeneration.

  When an excessive amount of phosphorus is present in the regenerated catalyst, the desulfurization active sites are covered with phosphorus in the preliminary sulfidation step, and the desulfurization activity may be reduced. For this reason, the amount of phosphorus contained in the regenerated catalyst is preferably about 10% by mass or less.

  In order to carry phosphorus on the fired product, a phosphoric acid compound is used as a raw material compound containing phosphorus. Examples of the phosphoric acid compound include orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, and tetraphosphoric acid. Among them, orthophosphoric acid is preferable. These phosphoric acid compounds can be used singly or in combination of two or more as required.

  The method for supporting the organic acid and phosphorus on the burned product of the used catalyst is not particularly limited, and any method known in the art may be used. For example, the loading of the organic acid and phosphorus on the burned product of the used catalyst can be performed using a solution containing the organic acid and the phosphoric acid compound. Specifically, it is carried out by impregnating the calcined product of the used catalyst with a solution containing an organic acid and a phosphoric acid compound. The impregnation solution containing the organic acid and the phosphoric acid compound can be prepared by a conventional method. The solvent used for dissolving the organic acid and the phosphorus compound is generally water.

Moreover, impregnation of the impregnated solution of the organic acid and the phosphoric acid compound into the calcined product of the used catalyst can be performed by a conventional method. Various conditions can be adopted as the impregnation conditions. Usually, the impregnation temperature is preferably more than 0 ° C. and less than 100 ° C., and the impregnation time is suitably from 15 minutes to 3 hours.
If the impregnation temperature is within the above range, drying occurs during the impregnation, and the dispersibility of the organic acid and the phosphoric acid compound does not decrease. If the impregnation time is within the above range, the organic acid and phosphorus are uniform in the fired product.

  A regenerated hydrotreating catalyst is obtained by impregnating an impregnating solution of an organic acid and a phosphoric acid compound and drying the used catalyst fired on the organic acid and phosphorus at 200 ° C. or lower. . The drying of the fired product of the used catalyst carrying the organic acid and phosphorus is not particularly limited as long as it is performed at 200 ° C. or lower. For example, in general, water is removed to a certain extent (so that the LOI is 50% or less) in a nitrogen stream, an air stream, or a vacuum in a room temperature to about 80 ° C., and then in an air stream, a nitrogen stream, Alternatively, drying is performed in vacuum at 200 ° C. or lower, preferably 80 to 200 ° C. for 5 to 20 hours. Here, when drying in a vacuum, it is preferable to perform the drying so as to be within the above temperature range in terms of pressure of 760 mmHg.

In the fired product of the above-mentioned used catalyst carrying an organic substance, the supported organic acid is complexed with the eighth metal of the periodic table supported on the used catalyst, and the supported phosphorus compound is converted into the used catalyst. It is thought that it is heteropolyized with the supported Group 6 metal of the periodic table.
Further, when drying is performed at a temperature of 200 ° C. or less, the organic acid complexed with the group 8 metal of the periodic table and the metal of the periodic table 6 which are supported on the used catalyst are heteropolyized. It is presumed that phosphorus is not desorbed from the metal, and as a result, precise control of formation of the CoMoS structure and NiMoS structure, which are considered to be active sites, is facilitated when the resulting catalyst is subjected to sulfurization treatment.

The hydrotreating catalyst regenerated as described above according to the present invention has sufficiently recovered its desulfurization activity and should be suitably used for hydrotreating hydrocarbon oils in the same manner as the hydrotreating catalyst before use. Can do. That is, the hydrotreating catalyst regenerated by the regeneration method of the present invention can ultra-desulfurize sulfur compounds in hydrocarbon oil without requiring severe operating conditions.
In addition, as a side mechanical strength (Side Crash Strength: SCS) of a catalyst, 2 lbs / mm or more is normally requested | required.

  Examples of the hydrotreating catalyst regenerated by the present invention include straight-run naphtha, catalytic reforming naphtha, catalytic cracking naphtha, catalytic cracking gasoline, straight-run kerosene, straight-run light oil, catalytic cracking light oil, pyrolysis light oil, hydrotreating. It can be suitably used for hydrotreating fractions such as light oil, desulfurized light oil, and vacuum distilled light oil (VGO). Typical examples of the properties of hydrocarbon oils that can be suitably hydrotreated by the hydrotreating catalyst regenerated by the present invention include those having a boiling range of 30 to 560 ° C. and a sulfur compound concentration of 5% by mass or less. It is done.

Further, the hydrotreatment of hydrocarbon oil as described above with the hydrotreating catalyst regenerated according to the present invention is generally performed with a hydrogen partial pressure of 0.7 to 20 MPa, a temperature of 220 to 420 ° C., and a liquid space velocity of 0.3 to It can be suitably carried out under the conditions of 10 hr ⁻¹ and a hydrogen / oil ratio of 20 to 1000 m ³ (normal) / kl.

  Hereinafter, although an example and a comparative example are given and the present invention is explained, the present invention is not limited to the following examples at all.

[Example 1]
<Manufacture of hydrotreating catalyst>
According to the method described in Example 1 in the pamphlet of International Publication No. 2004/054712, Catalyst A was produced as follows.
That is, after kneading and extruding SHY zeolite powder having an SiO ₂ / Al ₂ O ₃ molar ratio of 6 (average particle size of 3.5 μm, particle size of 6 μm or less is 87% of all zeolite particles) and alumina hydrate And a zeolite-alumina composite support in a columnar shaped product having a diameter of 1.5 mm after calcination at 600 ° C. for 2 hours (zeolite / alumina mass ratio: 5/95, pore volume: 0.79 ml / g, specific surface area: 311 m ² / g, average pore diameter: 93 mm).

10.23 g of cobaltous citrate and 2.24 g of phosphoric acid (85% aqueous solution) were added to 22.3 g of ion-exchanged water, heated to 80 ° C. and stirred for 10 minutes. Next, 17.61 g of molybdophosphoric acid was added and dissolved, and stirred at the same temperature for 15 minutes to prepare a solution for impregnation.
Into an eggplant-shaped flask, 30.0 g of the inorganic oxide carrier of the above zeolite-alumina composite was put, and the whole amount of the above impregnating solution was added thereto with a pipette and immersed at about 25 ° C. for 3 hours. Thereafter, it was air-dried in a nitrogen stream, and dried in a muffle furnace, in an air stream, at atmospheric pressure, and 120 ° C. for about 16 hours to obtain catalyst i.

<Use of hydrotreating catalyst>
This catalyst (i) was used as a raw material gas oil (sulfur content: 1.61% by mass, density (15/4 ° C.): 0.8570 g / cm ³ ), pressure (hydrogen partial pressure): 4.9 MPa, liquid space velocity : Hydrogenation treatment was performed so that the sulfur content of the produced oil was 10 ppm or less under the condition of 1.5 hr ⁻¹ , and it was used until its activity was lowered to an unacceptable level.

<Regeneration of spent hydrotreating catalyst>
The catalyst was extracted from the reactor and treated in an air atmosphere at 300 ° C. for 3 hours to remove hydrocarbon oil remaining in the used catalyst. Further, impurities mainly composed of carbon precipitated on the used catalyst from which the residual hydrocarbon oil was removed were removed by calcination at 430 ° C. for 4 hours.

Then, the obtained fired product was impregnated with 26.00 g of an aqueous solution containing 5.34 g of citric acid monohydrate as an organic acid and 3.09 g of orthophosphoric acid (85% aqueous solution) as a phosphoric acid compound. The molar ratio of [citric acid] / [CoO] is 0.67 with respect to cobalt contained in the fired product (catalyst), and [money equivalent to P ₂ O ₅ ] / molybdenum contained in the fired product. The fired product was supported with an organic acid and phosphorus so that the molar ratio of [MoO ₃ ] was 0.15. Further, the fired product after impregnation was dried at 120 ° C. for 16 hours in a muffle furnace to obtain Catalyst A.

[Example 2]
As the impregnating liquid to be impregnated into the fired product, an aqueous solution of 26.00 g containing 5.34 g of citric acid monohydrate and 3.86 g of orthophosphoric acid (85% aqueous solution) as a phosphoric acid compound is included in the fired product. The molar ratio of [citric acid] / [CoO] to cobalt is 0.67, and the molar ratio of [P ₂ O ₅ equivalent] / [MoO ₃ ] is 0. 0 to molybdenum contained in the catalyst. A catalyst B was obtained in the same manner as in Example 1 except that the calcined product was supported with citric acid and phosphorus so as to be 19.

[Example 3]
As an impregnation liquid to be impregnated into the baked product, an aqueous solution of 26.00 g containing 5.34 g of citric acid monohydrate as an organic acid and 1.54 g of orthophosphoric acid (85% aqueous solution) as a phosphoric acid compound was used. The molar ratio of [citric acid] / [CoO] is 0.67 with respect to cobalt contained in the fired product after impregnation, and [P ₂ O ₅ equivalent] / [ Catalyst C was obtained in the same manner as in Example 1, except that the calcined product was supported with citric acid and phosphorus so that the molar ratio of MoO ₃ ] was 0.08.

[Example 4]
As an impregnating liquid to be impregnated into the calcined product, a catalyst (using a 26.00 g aqueous solution containing 7.21 g of citric acid monohydrate as an organic acid and 3.09 g of orthophosphoric acid (85% aqueous solution) as a phosphoric acid compound was used. The molar ratio of [citric acid] / [CoO] is 0.90 with respect to cobalt contained in the fired product after impregnation, and [P ₂ O ₅ equivalent] / [ Catalyst D was obtained in the same manner as in Example 1, except that the calcined product was supported with citric acid and phosphorus so that the molar ratio of MoO ₃ ] was 0.15.

[Example 5]
As an impregnating liquid to be impregnated into the calcined product, a catalyst (using a 26.00 g aqueous solution containing 4.88 g of citric acid monohydrate as an organic acid and 3.09 g of orthophosphoric acid (85% aqueous solution) as a phosphoric acid compound ( The molar ratio of [citric acid] / [CoO] is 0.61 with respect to cobalt contained in the fired product after impregnation, and [P ₂ O ₅ equivalent] / [ Catalyst E was obtained in the same manner as in Example 1, except that the calcined product was supported with citric acid and phosphorus so that the molar ratio of MoO ₃ ] was 0.15.

[Comparative Example 1]
As an impregnation liquid to be impregnated into the calcined product, an aqueous solution of 26.00 g containing 5.34 g of citric acid / monohydrate as an organic acid was used. Catalyst a was obtained in the same manner as in Example 1 except that only the citric acid was supported on the calcined product so that the molar ratio of [acid] / [CoO] was 0.67.

[Comparative Example 2]
As an impregnation liquid to be impregnated into the baked product, an aqueous solution of 26.00 g containing 5.34 g of citric acid monohydrate as an organic acid and 6.96 g of orthophosphoric acid (85% aqueous solution) as a phosphoric acid compound was used. The molar ratio of [citric acid] / [CoO] is 0.67 with respect to cobalt contained in the fired product after impregnation, and [P ₂ O ₅ equivalent] / [ Catalyst b was obtained in the same manner as in Example 1 except that the calcined product was supported with citric acid and phosphorus so that the molar ratio of MoO ₃ ] was 0.34.

[Comparative Example 3]
As an impregnating liquid to be impregnated into the calcined product, 26.00 g of an aqueous solution containing 5.34 g of citric acid monohydrate as an organic acid and 0.77 g of orthophosphoric acid (85% aqueous solution) as a phosphoric acid compound was used. The molar ratio of [citric acid] / [CoO] is 0.67 with respect to cobalt contained in the fired product after impregnation, and [P ₂ O ₅ equivalent] / [ Catalyst c was obtained in the same manner as in Example 1, except that the calcined product was supported with citric acid and phosphorus so that the molar ratio of MoO ₃ ] was 0.04.

[Comparative Example 4]
As an impregnation liquid to be impregnated into the calcined product, 26.00 g of an aqueous solution containing 4.00 g of citric acid monohydrate as an organic acid and 3.09 g of orthophosphoric acid (85% aqueous solution) as a phosphoric acid compound was used. The molar ratio of [citric acid] / [CoO] is 0.30 with respect to cobalt contained in the fired product after impregnation) and [P ₂ O ₅ equivalent] / [ Catalyst d was obtained in the same manner as in Example 1, except that the calcined product was supported with citric acid and phosphorus so that the molar ratio of MoO ₃ ] was 0.15.

<Analysis of regenerated catalyst>
The chemical composition and physical properties of the catalysts regenerated in the above examples and comparative examples were analyzed. Table 1 shows the elemental analysis values and physical property values of each catalyst.
The method and analytical equipment used for the analysis of the catalyst are shown below.

[Measurement of specific surface area]
The specific surface area of each catalyst was measured by the BET method by nitrogen adsorption. As the nitrogen adsorption device, a surface area measuring device (Bell Soap 28) manufactured by Nippon Bell Co., Ltd. was used.

(Measurement of pore volume, average pore diameter, and pore distribution)
The pore volume, average pore diameter, and pore distribution of each catalyst were measured by mercury porosimetry.
The mercury intrusion method is based on the law of capillary action. In the case of mercury and cylindrical pores, this law is expressed as:
D = − (1 / P) 4γcos θ
In the formula, D is the pore diameter, P is the applied pressure, γ is the surface tension, and θ is the contact angle. Measure the volume of mercury entering the pores as a function of the applied pressure P. The surface tension of the pore mercury of the catalyst was 484 dyne / cm 2 and the contact angle was 130 degrees. The pore volume is the total volume of mercury per gram of catalyst that has entered the pores, and the average pore diameter is the average value of D calculated as a function of P. Further, the pore distribution is a distribution of D calculated as a function of P.

Specifically, it measured as follows. In addition, the porosimeter (MICROMERITICS AUTO-PORE9200: Shimadzu Corporation make) was used for the mercury intrusion apparatus.
(1) The vacuum heating deaerator was turned on, and it was confirmed that the temperature was 400 ° C. and the degree of vacuum was 5 × 10 ⁻² Torr or less.
(2) The sample burette was emptied and placed on a vacuum heating deaerator.
(3) When the degree of vacuum was 5 × 10 ⁻² Torr or less, the sample burette was removed from the vacuum heat deaerator with its cock closed, and after cooling, the weight was measured.
(4) A sample (catalyst) was placed in a sample bullet.
(5) The sample-containing burette was placed in a vacuum heating and degassing apparatus and held for 1 hour or more after the degree of vacuum became 5 × 10 ⁻² Torr or less.
(6) The sample burette containing the sample was removed from the vacuum heating and degassing device, and after cooling, the weight was measured to obtain the sample weight.
(7) The sample was put into the cell for AUTO-PORE9200.
(8) Measured with AUTO-PORE 9200.

[Analysis of chemical composition]
a) Analysis of metal and phosphorus composition The composition of metal and phosphorus in each workplace was analyzed in terms of oxides. The analysis apparatus was performed using inductively coupled plasma emission spectrometry (ICPS-2000: manufactured by Shimadzu Corporation).
Specifically, 0.05 g of catalyst, 1 ml of hydrochloric acid (50%), one drop of hydrofluoric acid, and 1 cc of pure water were added to Uniseal and dissolved by heating. After dissolution, it was transferred to a polypropylene volumetric flask (50 ml), pure water was added and weighed to 50 ml. The obtained solution was measured by ICPS-2000. Metals and phosphorus were quantified by the absolute calibration curve method.

b) Analysis of Carbon Composition The carbon mass in each catalyst was combusted at 950 ° C. using a CHN analyzer (MT-5) manufactured by Yanagimoto Co., Ltd. Was measured with a differential thermal conductivity meter.

From the measured values (mass%) of CoO, MoO ₃ , P ₂ O ₅ , and C, the content (moles) of cobalt, molybdenum, phosphorus (in terms of P ₂ O ₅ ), and organic acid per unit amount of each catalyst ) Was calculated.
Since catalyst a does not carry phosphorus in the loading step, the value obtained by subtracting the phosphorus content in catalyst a from the phosphorus content in each catalyst is the value of the newly loaded phosphorus in each catalyst. The amount.
From each calculated content, the molar ratio of [citric acid] / [CoO] of each catalyst and the molar ratio of [P ₂ O ₅ equivalent] / [MoO ₃ ] were determined. Both molar ratios were confirmed to be the expected values (values described in each example and comparative example).

[Hydrolysis reaction of straight-run gas oil]
Using the catalysts A, B, C, D, E, a, b, c, and d prepared in the above Examples and Comparative Examples, hydrogenation of straight-run gas oil having the following properties was performed in the following manner. .
First, the catalyst was filled into a high-pressure flow reactor to form a fixed bed catalyst layer, and pretreatment was performed under the following conditions.
Next, a mixed fluid of the raw material oil heated to the reaction temperature and the hydrogen-containing gas is introduced from the upper part of the reactor, and the hydrogenation reaction proceeds under the following conditions, and the mixed fluid of the product oil and the gas is reacted. The oil was discharged from the lower part of the apparatus, and the produced oil was separated by a gas-liquid separator.

<Pretreatment conditions for catalyst>
Catalyst sulfidation: Liquid sulfidation with raw material oil was performed.
Pressure (hydrogen partial pressure): 4.9 MPa
Atmosphere: Hydrogen and raw material oil (liquid space velocity: 1.5 hr ⁻¹ , hydrogen / oil ratio: 200 m ³ (normal) / kl)
Temperature: Hydrogen and raw material oil are introduced at a room temperature of about 22 ° C., the temperature is raised at 20 ° C./hr, maintained at 300 ° C. for 24 hours, and then the reaction temperature is raised to 350 ° C. at 20 ° C./hr.

<Hydrogenation reaction conditions>
Reaction temperature: 350 ° C
Pressure (hydrogen partial pressure): 4.9 MPa
Liquid space velocity: 1.5 hr ⁻¹
Hydrogen / oil ratio: 200 m ³ (normal) / kl

<Properties of raw oil>
Oil type: Middle East straight run diesel oil density (15/4 ° C.): 0.8570 g / cm ³
Distillation properties: initial boiling point is 212.5 ° C, 50% point is 303.5 ° C, 90% point is 354.0 ° C, end point is 372.5 ° C
Sulfur component: 1.61% by mass
Nitrogen component: 140 mass ppm
Kinematic viscosity (30 ° C.): 5.857 cSt
Pour point: -2.5 ° C
Cloudy point: 1.0 ° C
Cetane index: 54.5
Saybolt color: -6

The reaction results were analyzed by the following method.
The reaction apparatus was operated at 350 ° C., and after 6 days, the product oil was collected and analyzed for its properties. Further, the desulfurization rate, desulfurization reaction rate constant, and specific activity were calculated as follows. These results are shown in Table 2.

[Calculation of Desulfurization Rate (HDS) (%)]
By converting the sulfur content in the raw material into hydrogen sulfide by a desulfurization reaction, the ratio of the sulfur content that disappeared from the raw material oil was defined as the desulfurization rate, and was calculated from the sulfur analysis values of the raw material oil and the product oil by the following formula. In the formula, Sf is a sulfur content (mass%) in the raw material oil, and Sp is a sulfur content (mass%) in the reaction product oil.
Desulfurization rate (%) = [(Sf−Sp) / Sf] × 100

[Calculation of desulfurization reaction rate constant (Ks)]
The constant of the reaction rate equation that obtains the reaction order of 1.3 with respect to the reduction amount of the sulfur content (Sp) of the product oil was defined as the desulfurization reaction rate constant (Ks). The higher the reaction rate constant, the better the catalytic activity. In the formula, Sf is the sulfur content (mass%) in the raw material oil, Sp is the sulfur content (mass%) in the reaction product oil, and LHSV is the liquid space velocity (hr-1).
Desulfurization reaction rate constant = [1 / (Sp) ^(1.3-1) −1 / (Sf) ^(1.3-1) ] × (LHSV) × 1 / (1.3-1)

[Calculation of specific activity (%)]
Based on the activity of the catalyst a, the specific activity of each catalyst was calculated from the following equation.
Specific activity (%) = (each desulfurization reaction rate constant / desulfurization reaction rate constant of comparative catalyst a) × 100

As a result, the specific activity with respect to the catalyst a was higher than 100% in any catalyst. From this, it is clear that in the regeneration step, a catalyst having both citric acid and phosphoric acid supported thereon can obtain a hydrotreating catalyst having a higher desulfurization activity than the catalyst a supporting only citric acid. It is.
Further, in the catalyst after regeneration, the molar ratio of the molar ratio of [citric acid] / [CoO] is in the range of 0.6-1, and _[P 2 _{O 5} equivalent amount) / (MoO _3] 0 Catalysts A to E in the range of 0.05 to 0.3 had significantly higher desulfurization activity than the catalysts a to d in which at least one of the molar ratios was out of the range. From these results, in the regeneration of the hydrotreating catalyst, the molar ratio of [organic acid] / [group 8 metal of periodic table] in the catalyst and [P ₂ O ₅ equivalent] / [group 6 of periodic table] It is clear that by supporting the organic acid and phosphorus so that the molar ratio of [metal] is within a specific range, a regenerated catalyst having a desulfurization activity that has been fully restored can be obtained.

Claims (1)

Oil removal treatment is performed on a hydrotreating catalyst loaded with a periodic group 6 metal, a periodic group 8 metal, and phosphorus, which has been used for hydrotreating a hydrocarbon oil, and which has been used. Oil removal process,
A calcining step of calcining the hydrotreating catalyst after the oil removal step at 300 to 600 ° C .;
In the fired product obtained by the firing step, an organic acid and phosphorus, [organic acid] / [group 8 metal of the periodic table] molar ratio is 0.6 to 1, and [supporting step after the firing step] Supporting so that the molar ratio of phosphorus excluding phosphorus contained in the previous fired product (in terms of P ₂ O ₅ ) / [Group 6 metal of the periodic table] is 0.05 to 0.3 Process,
And a method for regenerating a spent hydrocarbon oil hydrotreating catalyst, comprising a drying step of drying the calcined product after the supporting step at 200 ° C. or lower.