JP5396008B2 - Method for producing alkylbenzenes - Google Patents

Description

  The present invention relates to a process for producing alkylbenzenes from heavy hydrocarbon oils, and in particular, purifies heavy hydrocarbon oils containing polycyclic aromatic hydrocarbons, reduces impurities in the gas, and then hydrogenates them. The present invention relates to a method for producing alkylbenzenes which are decomposed and efficiently converted into alkylbenzenes (single-ring aromatic hydrocarbons) represented by benzene, toluene, xylene and the like.

  The recent demand for petroleum products is becoming lighter, and in particular, the demand for petrochemical raw materials represented by BTX (benzene, toluene, xylene) is increasing. In addition to BTX, aromatic hydrocarbons have a high octane number as a whole, and are therefore often used in gasoline base materials. A fluid catalytic cracking process can be mentioned as a method for efficiently producing a naphtha fraction containing an aromatic hydrocarbon component represented by BTX. Usually, about 50% of the naphtha fraction is obtained. Hydrogen remains at about 20%, and BTX is less than 10% of naphtha. Similarly, a catalytic reforming process can be cited as a method for selectively producing aromatic hydrocarbons, but the feedstock is limited to a naphtha fraction having an equivalent boiling range. For this reason, from the viewpoint of diversification of raw material oil and a cheaper raw material oil, a method for efficiently producing the target aromatic hydrocarbon from a heavier fraction is expected.

  As a method for producing light hydrocarbon oil by decomposing heavy hydrocarbon oil, in addition to fluid catalytic cracking process, a method of hydrocracking vacuum gas oil is widely adopted. In hydrocracking of vacuum gas oil, the target fraction can be obtained by bringing the feedstock into contact with the catalyst at a high temperature in the presence of high-pressure hydrogen. Conventionally, boiling points of about 150 to It has been used to produce a 370 ° C. fraction. Therefore, until now, a method of obtaining desirable properties as light oil or jet fuel, that is, a method of reducing aromatic content as much as possible has been adopted.

  Since medium heavy oil contains a large amount of sulfur and nitrogen, a method of installing a hydrorefining step for removing these impurities prior to hydrocracking is widely adopted. In addition, for light oil products that are expected to reduce the sulfur concentration to 10 ppm by weight or less without deteriorating the hue, the hue is improved while a high degree of desulfurization is advanced by adding a temperature difference in the two-stage reaction. The method of making it take was taken.

  On the other hand, looking at the various base materials obtained from the petroleum refining process, the use of fractions with a high sulfur content or aromatics as a fuel tends to decrease from the viewpoint of environmental friendliness in Japan and overseas. It is in. For example, gas oil fractions obtained from fluidized bed catalytic cracking processes, so-called Light Cycle Oil (LCO) and gas oil fractions obtained from thermal cracking equipment contain a large amount of sulfur and polycyclic aromatics and are used as light oil. Then, since sulfur oxide and particulate matter are discharged during combustion, it is difficult to mix and use a large amount.

  Patent Documents 1 and 2 also propose a method for producing a gasoline fraction by hydrocracking an LCO fraction. However, a relatively mild reaction is performed in order to leave a light oil fraction to some extent, and a gasoline fraction is produced. The conversion rate to a lighter fraction than the light oil fraction such as is suppressed. Patent Document 3 discloses a method for producing a kerosene fraction or a naphtha fraction by hydrocracking a feedstock obtained by mixing an LCO fraction with VGO (vacuum gas oil). Is not a method for preferentially producing BTXs. Patent Document 4 discloses a method for lightening a heavy aromatic hydrocarbon having 9 or more carbon atoms, but there is no information on the number of aromatic rings, and there are two or more aromatic hydrocarbons. The difficulty of converting from 1 to aromatic hydrocarbons is not recognized. Non-Patent Document 1 also proposes a method for partially producing BTX using LCO as a raw material oil. Similarly, the purpose is to produce light oil and gasoline, and in the method for producing BTX with priority. There wasn't. Similarly, Non-Patent Document 2 discloses a method for producing high-octane gasoline by hydrocracking 1-methylnaphthalene, which is a bicyclic aromatic hydrocarbon contained in a large amount in the LCO fraction, Since this reaction produces a large amount of paraffin and isoparaffin, the octane number is still as low as about 85, and it is not a method for selectively producing monocyclic aromatic hydrocarbons.

On the other hand, in Patent Document 5, a gas-liquid separation device is installed between the two-column reactions as a method for reducing the sulfur content of light oil, and the hydrogen sulfide produced in the first column is separated to reduce the load on the subsequent catalyst. A method for producing desulfurized gas oil has been proposed. However, in this case as well, this is a method for producing light oil, particularly a low temperature reaction for the purpose of improving the hue, and there is no description about the influence of the nitrogen content. Patent Documents 6 and 7 describe a method for producing a desulfurized gas oil by reducing it to a specific target sulfur concentration, but this is also a method for producing a gas oil, which is a harsh condition that can be converted to alkylbenzenes. It was not a good reaction.
A method of producing naphthene by nuclear hydrogenation of polycyclic aromatic hydrocarbons, a method of partial nuclear hydrogenation of polycyclic aromatic hydrocarbons, and reducing hydrogen sulfide produced in the first column in a two-column reaction. Although various methods for reducing the catalyst load in the second column have been proposed, a method for selectively producing alkylbenzenes represented by BTX using heavy hydrocarbons as a raw material has not been established so far.
Japanese Patent No. 3001963 Japanese Patent Publication No. 3-170598 International Publication No. 2006/062712 Pamphlet Japanese Patent No. 3302553 JP 2000-212578 A International Publication No. 2001/074973 Pamphlet International Publication No. 2002/010314 Pamphlet Thakkar et al. , National Petrochemical & Refiners Association, Annual Meeting, AM-05-53 (2005). Demirel et al. , Fuel, Vol. 77, no. 4, p301-311 (1998)

  Under such circumstances, the present invention provides a method for producing alkylbenzenes that purify heavy hydrocarbon oils containing polycyclic aromatic hydrocarbons, reduce impurities in the gas, and then hydrocrack, In particular, hydrocracking and converting to light hydrocarbon fractions without causing problems such as coking, and providing a method for efficiently and selectively producing monocyclic aromatic hydrocarbons, which are high-value-added alkylbenzenes It is intended to do.

As a result of intensive studies, the present inventor has selected a hydrocracking method using a catalyst in which the balance between hydrogenation activity and cracking activity is highly controlled, so that a monocyclic aromatic hydrocarbon typified by alkylbenzene is used. In addition, the inventors have found that various light hydrocarbon fractions can be efficiently produced, and have arrived at the method for producing alkylbenzenes of the present invention.
That is, the present invention is as follows.
(1) A first step for refining a heavy hydrocarbon oil containing polycyclic aromatic hydrocarbons, a second step for reducing impurities in the gas produced in the first step, and a refined oil obtained in the second step A process for producing alkylbenzenes (single-ring aromatic hydrocarbons) comprising a third step of hydrocracking, wherein the heavy hydrocarbon oil has a content of one-ring aromatic hydrocarbon of less than 10% by volume, The ratio of carbon constituting the aromatic ring to the total carbon (aromatic ring constituting carbon ratio) is 35 mol% or more, and in the third step, the refined oil is brought into contact with the hydrocracking catalyst in the presence of hydrogen. A hydrocracked product oil containing at least 10 vol% of a fraction having a boiling point of 215 ° C or higher contained in a heavy hydrocarbon oil and converting it to a fraction below 215 ° C by containing 10 vol% or more of a monocyclic aromatic hydrocarbon A process for producing alkylbenzenes to obtain
(2) In the above (1), the ratio of the aromatic ring constituent carbon ratio of the hydrocracked product oil to the aromatic ring constituent carbon ratio of the heavy hydrocarbon oil (aromatic ring carbon residual ratio) is 0.5 or more. A method for producing the alkylbenzenes described.

  According to the method for producing alkylbenzenes of the present invention, when a heavy hydrocarbon oil containing a large amount of polycyclic aromatic hydrocarbons is used as a raw material and brought into contact with an optimal hydrocracking catalyst in the presence of hydrogen, As a treatment method, the sulfur and nitrogen components that cause poisoning of the hydrocracking catalyst are hydrorefined and the gas content such as generated hydrogen sulfide is reduced to avoid the effects of catalyst poisoning. A high-boiling hydrocarbon fraction is converted into a low-boiling hydrocarbon fraction, and high-value-added alkylbenzenes (single-ring aromatic hydrocarbons) represented by BTX are efficiently produced. In addition, since a hydrocracking catalyst having a specific composition and physical properties that are optimally balanced for hydrocracking and having a suitable balance between cracking activity and hydrogenating activity is used, gas generation due to overcracking is suppressed, In addition, a decrease in activity due to coking due to insufficient hydrogenation ability is suppressed.

  In the present invention, the polycyclic aromatic hydrocarbon refers to a hydrocarbon having two or more aromatic rings, and the one-ring aromatic hydrocarbon is obtained by substituting hydrogen of benzene with 0 to 6 chain hydrocarbon groups. It is also called alkylbenzenes. The 1.5-ring aromatic hydrocarbon is one saturated aromatic ring such as tetralin (1,2,3,4-tetrahydronaphthalene) or indane (2,3-dihydroindene). The compound which has the naphthene ring of 1 in 1 molecule.

  Hereinafter, regarding the method for producing alkylbenzenes of the present invention, a raw material oil, a pretreatment method for purifying the raw material oil prior to hydrocracking (first step) and reducing impurities in the gas (second step), hydrogenation The cracking (third step), hydrocracking catalyst, hydrocracking catalyst manufacturing method, hydrocracking product oil refining method, and product hydrocarbon will be described in order.

[Raw oil]
In the present invention, the heavy hydrocarbon oil used as a raw material contains a polycyclic aromatic hydrocarbon, and the ratio of the carbon constituting the aromatic ring to the total carbon in the hydrocarbon oil (ratio of aromatic ring constituting carbon) ) Is 35 mol% or more, preferably 40 mol% or more, particularly preferably 45 mol% or more. Here, when the ratio of the aromatic ring constituting carbon in all the carbons is less than 35 mol%, the desired monocyclic aromatic hydrocarbon (alkylbenzenes) cannot be obtained in a high yield, which is not preferable. The aromatic ring constituting carbon ratio can be calculated by measuring ¹³ C-NMR using a nuclear magnetic resonance apparatus (NMR).

  In addition, the larger the number of aromatic rings, the better, but from the viewpoint of preferentially producing a single aromatic ring, the polycyclic aromatic compound in the raw material is preferably a bicyclic one. Among them, the polycyclic aromatics in the raw material are preferably those having 3 or more rings, and those having 1.5 or 2 rings are more preferable. The content of aromatic hydrocarbons of 3 or more rings is preferably 5.0% by volume or less, more preferably 3.0% by volume or less, and particularly preferably 1.0% by volume or less. Hydrogen is preferably 10% by volume or more, more preferably 20% by volume or more, and particularly preferably 30% by volume or more. It preferably contains 50% by volume or more of aromatic hydrocarbons (total of 1 ring, 1.5 ring and 2 ring aromatic hydrocarbons) of less than 3 rings, more preferably 60% by volume or more, particularly preferably 70 volumes. % Or more can be suitably used.

  A preferable distillation property can be set based on the aromatic composition. That is, in consideration of the boiling point (218 ° C.) of the bicyclic aromatic hydrocarbon naphthalene, the fraction of at least 215 to 280 ° C. is 10% by volume or more, and the fraction of 215 ° C. or more is 30% by volume or more. Preferably it is 40 volume% or more. Therefore, as a preferable distillation property of the raw material oil, the 10% distillation temperature is 100 to 230 ° C, more preferably 140 to 230 ° C, still more preferably 150 to 220 ° C, and the 90% distillation temperature is 230 to 600 ° C. More preferably, it is 230-400 degreeC, Furthermore, 230-310 degreeC, Especially 265-300 degreeC.

  Examples of the hydrocracking reaction inhibitor include nitrogen and sulfur. The raw material usually contains about 0.1 to 3,000 ppm by weight of nitrogen and about 0.1 to 3% by weight of sulfur. The main sulfur compounds are benzothiophenes, dibenzothiophenes, and sulfides, but there are many benzothiophenes and dibenzothiophenes in the boiling range of the raw material oil used in the present invention. Since dibenzothiophene is electronically delocalized and is stable and difficult to react, it is preferable that dibenzothiophene is not contained in the feedstock oil used in the present invention. Prior to supply to the hydrocracking step (third step), the feedstock oil is refined in the first step and second step as described below, so that the nitrogen and sulfur contents are reduced so as not to inhibit the hydrocracking reaction. The

In the present invention, as a heavy hydrocarbon oil containing a polycyclic aromatic hydrocarbon used as a raw material, the ratio of carbon constituting the aromatic ring to the total carbon in the hydrocarbon oil (aromatic ring constituting carbon ratio) is 35. Any hydrocarbon oil containing at least 30% by volume of a fraction having a boiling point of 215 ° C. or higher and having a boiling point of 215 ° C. or higher can be used.
Specifically, distillate obtained by atmospheric distillation of crude oil, vacuum gas oil obtained by vacuum distillation of atmospheric residue, lightening process of various heavy oils (catalytic cracking equipment, thermal cracking equipment, etc.) Distillates obtained from, for example, catalytic cracking oil (particularly LCO) obtained from catalytic cracking equipment, thermal cracking oil obtained from thermal cracking equipment (coker, visbreaking, etc.), ethylene cracker heavy obtained from ethylene cracker Residue, catalytic reformed oil obtained from catalytic reformer, and aromatic rich catalytic reformed oil obtained by extraction, distillation, or membrane separation of catalytic reformed oil (here, aromatic rich catalytic reforming) Oil refers to a product having a carbon number of 10 or more obtained from a catalytic reformer and an aromatic ring-containing compound content exceeding 50% by volume), and a fraction obtained from an aromatic extractor for producing a lubricating oil base oil. Min And aromatic-rich fraction obtained from the medium dewaxing apparatus. In addition, desulfurization method or hydroconversion method to purify atmospheric distillation residue, vacuum distillation residue, dewaxed oil, oil sand, oil shale, coal, biomass, etc. (for example, heavy oil decomposition such as H-Oil process, OCR process, etc.) A distillate produced from a process or a cracking process of heavy oil with a supercritical fluid) can also be preferably used.

[Purification step (first step)]
In the present invention, polycyclic aromatic hydrocarbons are selectively converted into monocyclic aromatic hydrocarbons by hydrocracking treatment, but by performing pretreatment prior to the hydrocracking treatment (third step), The catalytic performance of the hydrocracking step can be fully exhibited. There are various raw materials as described above, and the contents of sulfur compounds and nitrogen compounds contained therein are also various. Therefore, particularly when the concentration is too high, the function of the hydrocracking catalyst may not be fully exhibited. Therefore, before the hydrocracking step, a first step is performed in which a known purification method is applied in advance to reduce sulfur and nitrogen. Examples of the pretreatment method include hydrorefining, adsorption separation, sorption separation, oxidation treatment and the like, and hydrorefining is particularly preferable. In the case of coping with hydrorefining, the raw material before purification and the hydrotreating catalyst are subjected to pressure in the presence of hydrogen at a temperature of 150 to 400 ° C, more preferably 200 to 380 ° C, and even more preferably 250 to 360 ° C. 1 to 10 MPa, more preferably 2 to 8 MPa, liquid space velocity (LHSV) 0.1 to 10.0 h ⁻¹ , more preferably 0.1 to 8.0 h ⁻¹ , still more preferably 0.2 to 5.0 h. ^-1 , hydrogen / hydrocarbon ratio (volume ratio) of 100 to 5,000 NL / L, preferably 150 to 3,000 NL / L.

  By the treatment in the first step, the sulfur content is preferably 500 ppm by weight or less, more preferably 100 ppm by weight or less, particularly preferably 50 ppm by weight or less, and the nitrogen content is preferably 100 ppm by weight or less, more preferably 20 ppm by weight or less. Particularly preferably, it is reduced to 10 ppm by weight or less. Along with the desulfurization and denitrogenation reactions by this hydrorefining treatment, the hydrogenation of aromatics also proceeds partially. In the present invention, there is no problem in reducing the amount of polycyclic aromatic hydrocarbons, but it is not desirable to reduce the amount of monocyclic aromatic hydrocarbons. Accordingly, it is preferable to treat the reaction conditions so that the polycyclic aromatic component can be hydrogenated to a single ring or 1.5 ring aromatic hydrocarbon. For this purpose, the reaction is performed on a volume basis. It is preferable to control the total aromatic hydrocarbon amount so that 0.50 or more before the reaction remains, and a more preferable residual ratio is 0.60 or more, and further preferably 0.70 or more.

  Although it does not specifically limit as a hydrorefining catalyst used for the hydrotreating of a 1st process, At least 1 type of metal chosen from the 6th group and the 8th group of a periodic table is added to a refractory oxide support | carrier. A supported catalyst can be preferably used. As such a catalyst, specifically, a support containing at least one selected from alumina, silica, boria and zeolite, molybdenum, tungsten, nickel as metals of Group 6 and Group 8 of the periodic table, Examples thereof include a catalyst on which at least one metal selected from cobalt, platinum, palladium, iron, ruthenium, osmium, rhodium and iridium is supported. If necessary, the hydrorefining catalyst is used after drying, reduction, sulfidation, or the like before the hydrogenation reaction. Moreover, it is preferable to use the quantity of the catalyst used for a pretreatment process in 10-200 volume% with respect to a hydrocracking catalyst. Here, if it is 10% by volume or less, the removal of the sulfur content is insufficient, while if it is 200% by volume or more, the apparatus becomes large and inefficient.

[Gas impurity reduction process (second process)]
In the present invention, between the hydrorefining step that is the first step and the hydrocracking step that is the third step to be described later, as a second step, the gas-liquid of the effluent fluid from the hydrorefining reactor is separated, Part or all of the reaction exhaust gas used in the hydrorefining reaction is withdrawn out of the system, and the liquid (refined oil) from the hydrorefining reactor and the remainder of the reaction exhaust gas are hydrocracked (third step) ) In the hydrocracking process, hydrogen gas necessary for the reaction is supplemented by supplying fresh hydrogen gas to promote the reaction.
Hydrogen sulfide and ammonia produced in the hydrorefining process poison the 3rd process hydrocracking catalyst described later and reduce the activity. Therefore, these concentrations introduced into the 3rd process hydrocracking process. Is preferably less. The hydrogen sulfide in the hydrogen-containing gas introduced into the third step is preferably 0.1 mol% or less, more preferably 0.08 mol% or less, particularly preferably 0.06 mol% or less, and ammonia is 0.1 mol% or less. % Or less is preferable, 0.05 mol% or less is more preferable, and 0.03 mol% or less is particularly preferable.
Here, the second step is related to hydrogen sulfide and ammonia produced in the first step, and is intended to reduce the concentration in the gas introduced into the third step. A tower or an absorption tower may be used, or a part of the mixed gas generated in the first step may be extracted or diluted with a large amount of high-purity hydrogen.
Also, hydrogen sulfide and ammonia may be dissolved and contained in refined oil separated from gas and liquid, so hydrogen sulfide and ammonia can be added as much as possible by methods such as nitrogen gas bubbling, hydrogen gas bubbling, water washing and steam stripping. It is also effective to remove it. Thus, if it sends to a hydrocracking process (3rd process), catalyst poisoning is reduced and hydrocracking can be continued, without reducing activity for a long period of time.

[Hydrocracking step (third step)]
In the hydrocracking step, which is the third step in the present invention, the purified hydrocracking reaction raw material is explained in detail later in the presence of hydrogen with reduced gas content such as hydrogen sulfide and ammonia. Contacting with a cracking catalyst, 10% or more of the fraction having a boiling point of 215 ° C. or more is converted into a fraction having a boiling point of less than 215 ° C. to convert it into a hydrocracked product oil containing 10% by volume or more of a monocyclic aromatic hydrocarbon. That is, the hydrocarbon hydrocarbon of the fraction having a boiling point higher than a specific temperature contained in the hydrocarbon oil is converted from the raw material hydrocarbon oil, in other words, the number of aromatic rings of the polycyclic aromatic hydrocarbon is changed. It is reduced and converted to monocyclic aromatic hydrocarbons (alkylbenzenes) to produce hydrocracked product oil containing 10 vol% or more of monocyclic aromatic hydrocarbons.

  The reaction mode of hydrocracking of hydrocarbon oil in the present invention is not particularly limited, and conventionally used reaction modes, that is, a fixed bed, a boiling bed, a fluidized bed, a moving bed, etc. can be applied. . Among these, a fixed bed type is preferable, simple and easy to operate.

  In the hydrocracking method of hydrocarbon oil in the present invention, the hydrocracking catalyst is used after pretreatment such as drying, reduction, sulfidation, etc. after filling the reactor. These treatments are well known to those skilled in the art, and can be carried out appropriately in the reactor or outside the reactor. Activation of the catalyst by sulfurization is generally performed by treating the hydrocracking catalyst at a temperature of 150 to 500 ° C, preferably 200 to 400 ° C, under a hydrogen / hydrogen sulfide mixed stream.

In hydrocracking, for example, the operating conditions such as reaction temperature, reaction pressure, hydrogen flow rate, liquid space velocity, etc. are appropriately determined according to the properties of the raw material, the quality of the product oil, the production volume, and the capacity of the refinery / post-treatment facilities Adjust it. The raw hydrocarbon oil for hydrocracking reaction and the hydrocracking catalyst are reacted in the presence of hydrogen at a reaction temperature of 200 to 450 ° C, more preferably 250 to 430 ° C, more preferably 280 to 400 ° C, and a reaction pressure of 2 10 MPa, more preferably 2-8 MPa, liquid space velocity (LHSV) 0.1-10.0 h ⁻¹ , more preferably 0.2-5.0 h ⁻¹ , still more preferably 0.3-3.0 h. ^-1 , the hydrogen / hydrocarbon ratio (volume ratio) is 100 to 5,000 NL / L, preferably 150 to 3,000 NL / L. By the above operation, the polycyclic aromatic hydrocarbons in the raw hydrocarbon oil for the hydrocracking reaction are decomposed and converted into desired monocyclic aromatic hydrocarbons (alkylbenzenes). Outside the range of the above operating conditions, it is not preferable for reasons such as insufficient cracking activity or rapid deterioration of the catalyst.

[Hydrolysis catalyst]
The hydrocracking catalyst of the present invention carries at least one metal component selected from Group 6 and Group 8 of the periodic table on a support composed of a composite oxide and a binder binding the composite oxide, and pellets It is formed into a shape (columnar shape, irregular columnar shape), granular shape, spherical shape or the like. In addition, as the physical properties, the specific surface area is 100 to 800 m ² / g, the central pore diameter is 3 to 15 nm, and the pore volume occupied by the pores having the pore diameter of 2 to 60 nm is 0.1 to 1.0 mL / g. Preferably there is.

The specific surface area of the hydrocracking catalyst is a value of a BET specific surface area determined by nitrogen adsorption based on ASTM standard D3663-78, more preferably 150 to 700 m ² / g, and still more preferably 200 to 600 m ² / g. The central pore diameter is more preferably 4.0 to 12 nm, particularly preferably 5.0 to 10 nm. The pore volume occupied by pores having a pore diameter of 2 to 60 nm is more preferably 0.15 to 0.8 mL / g, and particularly preferably 0.2 to 0.7 mL / g.
When the BET specific surface area is smaller than the above range, the active metal dispersion is insufficient and the activity is not improved. Conversely, when the BET specific surface area is too large, there is generally a trade-off relationship between the specific surface area and the pore volume. Therefore, it is not preferable because a sufficient pore volume cannot be ensured, the reaction product is not sufficiently diffused, and the progress of the reaction is rapidly inhibited. The central pore diameter and the pore volume are not preferable if they are too large or too small because there is an appropriate range from the relationship between the size of molecules involved in the reaction and diffusion.

  The so-called mesopore pore characteristics, that is, the pore diameter and the pore volume can be measured by a nitrogen gas adsorption method, and the relationship between the pore volume and the pore diameter can be calculated by the BJH method or the like. The central pore diameter is defined as V, where V is the cumulative pore volume occupied by pores having a pore diameter of 2 to 60 nm obtained under the condition of a relative pressure of 0.9667 in the nitrogen gas adsorption method. In the cumulative pore volume curve obtained by accumulating the volume amount, it means the pore diameter at which the cumulative pore volume is V / 2.

  As the hydrocracking catalyst in the present invention, those having macropores, mesopores and micropores can be used. Usually, the mesopore pore characteristics of the composite oxide support are maintained until the catalyst is formed. Therefore, the mesopore pore characteristics of the hydrocracking catalyst are basically the fine characteristics of the composite oxide support. The pore characteristics can be adjusted by controlling the kneading conditions (time, temperature, torque) and firing conditions (time, temperature, composition and flow rate of atmospheric gas) so as to have the mesopore pore characteristics.

  The pore characteristics of the macropores can be controlled by the space between the composite oxide particles and the filling rate with the binder. The voids between the composite oxide particles can be controlled by the particle size distribution of the composite oxide particles, and the filling rate can be controlled by the blending amount of the binder.

  The pore characteristics of micropores largely depend mainly on the pores inherent in the composite oxide such as zeolite, but can also be controlled by dealumination treatment such as steaming.

  The pore characteristics of mesopores and macropores can also be influenced by the properties of the binder and the kneading conditions described below. The composite oxide is mixed with an inorganic oxide matrix (binder) to form a carrier.

[Composite oxide]
The composite oxide referred to in the present invention is a composite oxide having solid acidity. For example, in a binary composite oxide, K.I. Shibata, T .; Kiyoura, J. et al. Kitagawa, K .; Tanabé, Bull. Chem. Soc. Jpn. , 46, 2985 (1973), and many others are known. Among them, silica-alumina, silica-titania, silica-zirconia, and silica-magnesia can be preferably used as the composite oxide used in the present invention. As the ternary composite oxide, silica-alumina-titania and silica-alumina-zirconia can be preferably used. In addition, the composite oxide referred to in the present invention includes zeolite such as USY zeolite.

The composite oxide is selected from silica-alumina, silica-titania, silica-zirconia, silica-magnesia, silica-alumina-titania, silica-alumina-zirconia, tungsten oxide-zirconia, sulfated zirconia, alumina sulfate, zeolite 1 The species can be used alone, or two or more species can be used in combination. In particular, when silica-alumina is used as the composite oxide, it is preferably used so that the silica / alumina (SiO ₂ / Al ₂ O ₃ ) ratio (molar ratio) is 1 to 20.

  The zeolite is not particularly limited, but X-type, Y-type, β-type, MOR-type and MFI-type zeolites are preferable, and among them, Y-type, β-type and MFI-type zeolites can be suitably used. . Among the Y-type zeolite, an acidic type such as HY type obtained by ion-exchange of alkali metal is preferably used rather than an alkali metal type such as Na-Y type. Aluminum-treated USY-type zeolite (super stable Y-type zeolite) can also be used. This is obtained by acid treatment, high temperature treatment, steam treatment, etc., and has high resistance to crystallinity deterioration, and the content of alkali metal ions is less than 1.0% by weight, preferably 0.5%. It is characterized by a lattice constant of less than% by weight and not more than 2.46 nm and a silica / alumina ratio (molar ratio) of 5 or more.

The above-mentioned HY zeolite and USY zeolite used in the present invention can be prepared by any method as long as the molar ratio of aluminum to silicon is 1: 2.0 to 1: 10.0 and has a faujasite structure. Regardless, either can be used without any problem. In the present invention, it is preferable that the Y-type zeolite is first dealkalized, then steam-treated and / or acid-treated to obtain a crystalline aluminosilicate having a lattice constant of 2.43 to 2.46 nm. In the case where the lattice constant exceeds 2.46 nm, the crystal structure collapses when it comes into contact with an aqueous solution having a pH of less than 3 during the acid treatment described later, the decomposition activity is lowered, and the yield of the target fraction is reduced. On the other hand, when the lattice constant is less than 2.43 nm, the crystallinity is poor and the amount of acid is small, so that the decomposition activity similarly decreases and the yield of the target fraction decreases. Note that the lattice constant is calculated from the value of the interplanar distance d obtained by the X-ray diffraction method by the following equation.
Lattice constant = d × (h ² + k ² + l ² ) ^1/2
Here, h, k, and l are Miller indices.

The above dealkalization treatment is performed by immersing the Y-type zeolite in an ammonia-containing solution or the like, exchanging alkali metal ions such as Na ⁺ with ammonium ions or the like, and firing the same. First, H-Y type zeolite is obtained, and further, this series of treatments is repeated several times to prepare USY (Ultra Stable Y) type zeolite having a further reduced alkali metal content through SY (Stable Y) type zeolite. be able to. The alkali metal content of the dealuminated USY zeolite is preferably less than 1.0% by weight, and more preferably less than 0.5% by weight.

Further, the steam treatment may be performed by a method in which the dealkalized zeolite is brought into contact with steam at 500 to 800 ° C., preferably 550 to 750 ° C. Further, the acid treatment may be performed by immersing in an aqueous nitric acid solution having a pH of 3 or less. Either steam treatment or acid treatment may be used, but partial dealumination treatment is performed by using both treatments together, and a crystalline aluminosilicate having the above lattice constant is easily prepared by drying and firing. can do.
In addition to Y-type zeolite, β-type, MOR type typified by mordenite, and MFI type zeolite typified by ZSM-5 can also be used. In this case, since these zeolites have a high silica / alumina ratio, they can be used without any special dealumination treatment.

  Crystalline aluminosilicates with adjusted silica / alumina ratios in this way are used for transition metal salts such as iron, cobalt, nickel, molybdenum, tungsten, copper, zinc, chromium, titanium, vanadium, zirconia, cadmium, tin, and lead. In addition, these metal ions are introduced by dipping in a solution containing a rare earth salt such as lanthanum, cerium, ytterbium, europium, dysprosium, etc. Good. When the hydrocracking reaction described later is used, the crystalline aluminosilicate, the transition metal-containing crystalline aluminosilicate, or the rare earth-containing crystalline aluminosilicate may be used alone or in combination. May be.

[binder]
As the binder, porous and amorphous ones such as alumina, silica-alumina, titania-alumina, zirconia-alumina, and boria-alumina can be suitably used. Of these, alumina, silica-alumina, and boria-alumina are preferred because they have a strong ability to bind complex oxides and a high specific surface area. These inorganic oxides function as a substance that supports an active metal and also serve as a binder that binds the composite oxide, thereby improving the strength of the catalyst. The specific surface area of the binder is desirably 30 m ² / g or more.

  The binder which is one of the constituent components of the carrier is a powder made of aluminum hydroxide and / or hydrated oxide (hereinafter also simply referred to as alumina powder), in particular, an oxide having a boehmite structure such as pseudoboehmite. Aluminum monohydrate (hereinafter also simply referred to as alumina) is preferably used because it can improve hydrocracking activity and selectivity. Further, powders made of aluminum hydroxide and / or hydrated oxide containing boria (boron oxide), particularly aluminum oxide monohydrate having boehmite structure such as pseudoboehmite containing boria, are also hydrocracking activity. And can be preferably used because the selectivity can be improved.

  As aluminum oxide monohydrate, commercially available alumina sources (for example, PURAL (registered trademark), CATAPAL (registered trademark), DISPERAL (registered trademark), DISPAL (registered trademark), commercially available from SASOL, from UOP Commercially available VERSAL (registered trademark) or HIQ (registered trademark) commercially available from ALCOA, etc.) can be used. Alternatively, it can be prepared by a known method of partially dehydrating aluminum oxide trihydrate. When the aluminum oxide monohydrate is in the form of a gel, the gel is dissolved with water or acidic water. When alumina is synthesized by a precipitation method, the acidic aluminum source can be selected from aluminum chloride, aluminum sulfate, aluminum nitrate, and the like, and the basic aluminum source can be selected from sodium aluminate, potassium aluminate, and the like.

  The blending ratio of the binder is preferably 5 to 70% by weight, particularly 10 to 60% by weight, based on the total weight of the composite oxide and the binder constituting the catalyst. If it is less than 5% by weight, the mechanical strength of the catalyst tends to be lowered, and if it exceeds 70% by weight, the hydrocracking activity and selectivity are relatively lowered. When USY zeolite is used as the composite oxide, the weight of USY zeolite relative to the total weight of the composite oxide part and the binder part constituting the catalyst is preferably 1 to 80% by weight, particularly 10 to 70% by weight. If it is less than 1% by weight, the effect of improving the cracking activity due to the use of USY zeolite is hardly exhibited, and if it exceeds 80% by weight, the middle distillate selectivity is relatively lowered.

[Metal component]
The hydrocracking catalyst of the present invention contains a metal selected from Groups 6 and 8 of the periodic table as an active component. Of the Group 6 and Group 8 metals, molybdenum, tungsten, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, and platinum are particularly preferably used. These metals can be used alone or in combination of two or more. These metals are added so that the total amount of Group 6 and Group 8 metal elements in the hydrocracking catalyst is 0.05 to 35% by weight, particularly 0.1 to 30% by weight. It is preferable to do. When molybdenum is used as the metal, the content thereof is preferably 5 to 20% by weight, particularly 7 to 15% by weight in the hydrocracking catalyst. When tungsten is used as the metal, the content thereof is preferably 5 to 30% by weight, particularly 7 to 25% by weight in the hydrocracking catalyst. If the addition amount of molybdenum or tungsten is less than the above range, the hydrogenation function of the active metal necessary for the hydrocracking reaction is insufficient, which is not preferable. On the other hand, when the amount is larger than the above range, the added active metal component tends to aggregate and is not preferable.

When molybdenum or tungsten is used as the metal, it is more preferable to add cobalt or nickel to improve the hydrogenation function of the active metal. In this case, the total content of cobalt or nickel is preferably 0.5 to 10% by weight, particularly 1 to 7% by weight in the hydrocracking catalyst. When one or more of rhodium, iridium, platinum and palladium are used as the metal, the content is preferably 0.1 to 5% by weight, particularly preferably 0.2 to 3% by weight. If it is less than this range, a sufficient hydrogenation function cannot be obtained, and if it exceeds this range, the addition effect is small and it is not economical, which is not preferable.

The Group 6 metal component supported as the active component is an aqueous solution of a compound such as ammonium paramolybdate, molybdic acid, ammonium molybdate, phosphomolybdic acid, ammonium tungstate, tungstic acid, tungstic anhydride, or tungstophosphoric acid. Use it.
Group 8 metal components include nickel and cobalt nitrates, sulfates, chlorides, fluorides, bromides, acetates, carbonates, phosphates, aqueous solutions such as chloroplatinic acid, dichlorotetraammineplatinum, tetrachloro Hexammineplatinum, platinum chloride, platinum iodide, potassium chloroplatinate, palladium acetate, palladium chloride, palladium nitrate, palladium acetylacetonate, rhodium acetate, rhodium chloride, rhodium nitrate, ruthenium chloride, osmium chloride, iridium chloride, etc. An aqueous solution of
Further, phosphorus, boron, potassium, and rare earth such as lanthanum, cerium, ytterbium, europium, dysprosium may be added as the third component.

[Method for producing hydrocracking catalyst]
The hydrocracking catalyst of the present invention is prepared by kneading and molding a composite oxide and a binder, followed by drying and firing to prepare a carrier, and further impregnating and supporting a metal component, followed by drying and firing. Can do. The production method of the hydrocracking catalyst of the present invention will be described in detail below, but is not limited to the following method, and other methods capable of producing a catalyst having predetermined pore characteristics and performance may be used. it can.

  For kneading, a kneader generally used for catalyst preparation can be used. Usually, a method of adding raw materials, adding water and mixing with a stirring blade is preferably used, but there is no particular limitation on the order of adding raw materials and additives. Water is usually added at the time of kneading, but it is not particularly necessary to add water when the raw material is in the form of a slurry. In addition to water or instead of water, an organic solvent such as ethanol, isopropanol, acetone, methyl ethyl ketone, or methyl isobutyl ketone may be added. The kneading temperature and kneading time vary depending on the composite oxide and binder used as raw materials, but are not particularly limited as long as a preferable pore structure is obtained. Similarly, as long as the properties of the catalyst of the present invention are maintained, an acid such as nitric acid, a base such as ammonia, an organic compound such as citric acid and ethylene glycol, a water-soluble property such as cellulose ethers and polyvinyl alcohol. A high molecular compound, ceramic fiber, etc. may be added and kneaded.

After kneading, it can be molded using a known molding method generally used for catalyst preparation. In particular, extrusion using a screw-type extruder that can be efficiently molded into any shape such as pellets (columnar, irregular columnar), granules, and spheres, and molding by an oil drop method that can be efficiently molded into spheres. Preferably used. Although there is no restriction | limiting in particular in the size of a molded object, For example, if it is a column-shaped pellet, a thing about 0.5-20 mm in diameter and 0.5-15 mm in length can be obtained easily.
The molded product obtained as described above is used as a carrier by drying and baking treatment. This firing process may be performed at a temperature of 300 to 900 ° C. for 0.1 to 20 hours in a gas atmosphere such as air or nitrogen.

  There is no particular limitation on the method for supporting the metal component on the carrier. Prepare an aqueous solution of metal oxides or their salts, such as nitrates, acetates, carbonates, phosphates, halides, etc. that you want to support, and support them by spraying, impregnation by immersion, ion exchange, etc. . More metal components can be supported by repeating the supporting process and the drying process.

  For example, the carrier is impregnated with an aqueous solution containing a Group 6 metal component, and then dried at room temperature to 150 ° C., preferably 100 to 130 ° C. for 0.5 hour or more, or without drying, the Group 8 is left as it is. After impregnating with an aqueous solution containing the above metal components and drying at room temperature to 150 ° C., preferably 100 to 130 ° C. for 0.5 hours or more, 350 to 800 ° C., preferably 450 to 600 ° C. for 0.5 hours or more. The catalyst can be prepared by calcination.

  The Group 6 and Group 8 metals supported on the catalyst of the present invention may be in any form such as metals, oxides, and sulfides.

[Mechanical strength of hydrocracking catalyst and support]
The mechanical strength of the hydrocracking catalyst is preferably as high as possible. For example, in the case of a cylindrical pellet having a diameter of 1.6 mm, the side crushing strength when using a probe having a diameter of 5 mm (cylindrical) described later is preferably 3 kgf or more. More preferably, it is 4 kgf or more. In the case where a catalyst is prepared by impregnating and supporting a metal component after the molded carrier is prepared, it is preferable that the molded carrier also has sufficient mechanical strength in order to produce the catalyst with good yield. Specifically, the mechanical strength of the molded carrier in the present invention is preferably 3 kgf or more, more preferably 4 kgf or more, as the side crushing strength of a cylindrical pellet having a diameter of 1.6 mm.

The bulk density of the catalyst is preferably 0.4 to 2.0 g / cm ³ , more preferably 0.5 to 1.5 g / cm ³ , and particularly preferably 0.6 to 1.2 g / cm ³ .

[Properties of hydrocracked oil]
In the hydrocracking step, 10% by volume or more of the fraction corresponding to a boiling point of 215 ° C. or higher in the raw hydrocarbon oil is converted into a fraction of less than 215 ° C. The hydrocracked product oil has a hydrocarbon having a boiling point of 215 ° C. or lower, that is, a hydrocarbon lighter than naphthalene, in an amount of 10% by volume or more, preferably 20% by volume or more, more preferably 25% by volume or more. . The hydrocracked product oil contains 10% by volume or more of monocyclic aromatic hydrocarbons (alkylbenzenes). The preferred content of monocyclic aromatic hydrocarbon is 15% by volume or more. Further, the 1.5 ring aromatic hydrocarbon is preferably contained in an amount of 45% by volume or less, more preferably 40% by volume or less. The polycyclic aromatic hydrocarbon having two or more rings is preferably contained in an amount of 10% by volume or less, and more preferably 8% by volume or less.
Furthermore, the ratio of the carbon ratio constituting the aromatic ring in the hydrocracked product oil to the carbon ratio constituting the aromatic ring in the raw hydrocarbon oil (aromatic ring carbon residual ratio) is 0.5 or more More preferably, it is 0.6 or more, and particularly preferably 0.7 or more. Here, when the aromatic ring carbon residual ratio is smaller than 0.5, it is impossible to obtain a large amount of the target product, one ring aromatic hydrocarbon, and it causes coking such as excessive decomposition reaction. This is not preferable because the catalyst life is shortened.

[Post-processing process]
In the present invention, it is also possible to install a post-processing step as necessary, as in the pre-processing step. Although a post-processing process is not specifically limited, The catalyst kind, catalyst amount, and reaction conditions similar to a pre-processing process can be set. The post-treatment step may be installed immediately after the hydrocracking step to treat the hydrocracked product oil, or may be treated after each hydrocarbon fraction that has been installed and separated after the subsequent separation step. Also good. By installing this post-treatment process, impurities in the product can be greatly reduced. For example, the sulfur content and the nitrogen content can be 0.1 ppm by weight or less.

[Method for separating hydrocracked product oil]
The hydrocracked product oil of the present invention is subjected to an appropriate separation step to products such as LPG fraction, gasoline fraction, kerosene fraction, light oil fraction, non-aromatic naphtha fraction, and monocyclic aromatic hydrocarbons. Processed. These products can be used as they are as LPG, gasoline, kerosene, light oil and petrochemical raw materials as long as they satisfy the standards for petroleum products, etc. Used as a substrate. The separation process is not particularly limited, and any known method such as precision distillation, adsorption separation, sorption separation, extraction separation, membrane separation or the like can be adopted according to the product properties. Moreover, what is necessary is just to set those operating conditions suitably.

  A distillation method that is widely used in general is a distillation method, which can be separated into, for example, an LPG fraction, a gasoline fraction, a kerosene fraction, and a light oil fraction by utilizing a difference in boiling points. Specifically, the portion having a boiling point of −10 to 30 ° C. is the LPG fraction, the portion having a boiling point of 30 to 215 ° C. is the gasoline fraction, the portion having a higher boiling point of 215 to 260 ° C. is the kerosene fraction, and A portion having a higher boiling point up to 260 to 370 ° C. can be used as a light oil fraction, and a heavier fraction can be treated again in the hydrocracking step as an unreacted product, You may use for the base material.

  In the case of the extraction method for separating the aromatic component, it can be separated into an aromatic component and a non-aromatic component using an appropriate solvent, but may be used in appropriate combination with the above distillation method. In this case, the gasoline fraction and / or kerosene fraction obtained from the distillation separation is used to mix a solvent for selectively extracting aromatics, for example, sulfolane (tetrahydrothiophene dioxide), and the temperature is 20-100. Extraction fraction in which aromatic compounds are selectively extracted with sulfolane and raffinate in which paraffinic hydrocarbons that are not extracted into sulfolane are concentrated by processing under the extraction conditions of ℃ and pressure from normal pressure to 1.0 MPa It is separated into fractions. Since the extract fraction containing a boiling point component of at least 80 ° C. obtained by this extraction process selectively extracts aromatic compounds, an aromatic base material can be obtained by hydrotreating as necessary. Can be used for products. In addition, since the raffinate fraction contains a relatively large amount of isoparaffin and naphthene, it can be used as it is as a gasoline base material for producing a high octane gasoline composition, and further used as a feedstock for a catalytic reforming process. Can also be converted to aromatic hydrocarbons.

  The aromatic fraction of the extract fraction extracted with sulfolane and sulfolane are easily separated by distillation operation, and the separated sulfolane is reused as an extraction solvent. The separated aromatic component can be converted into paraxylene, benzene, or the like having higher added value through a transalkylation treatment, an isomerization treatment, or the like.

[Product hydrocarbon]
The hydrocarbon products obtained through the above separation step include an LPG fraction having a boiling point of -10 to 30 ° C, a gasoline fraction having a boiling point of 30 to 215 ° C, a kerosene fraction having a boiling point of 215 to 260 ° C, and a boiling point of 260 to 370 ° C. And the residue remaining after separating the above fraction. In the present invention, the smaller the residue, the better, and it can also be recycled to the hydrocracking process to make it lighter.
In addition, an extract fraction and a raffinate fraction can be obtained by extracting a gasoline fraction with a solvent such as sulfolane. The raffinate fraction is a non-aromatic naphtha fraction and is useful as a gasoline base material, a solvent raw material and the like. The extract fraction is a monocyclic aromatic hydrocarbon (alkylbenzenes) useful as a petrochemical raw material.

  Hereafter, the manufacturing method of the alkylbenzenes of this invention is demonstrated in detail and concretely using an Example and a comparative example.

[Hydro-refining catalyst]
As a hydrorefining catalyst, catalyst A which is a commercially available NiMoP-supported desulfurization catalyst was used. The composition of the catalyst A was 12.3% by weight of Mo, 3.5% by weight of Ni, 2.0% by weight of P, and 43.3% by weight of Al.
When the pore characteristics of this catalyst A were measured by a nitrogen gas adsorption method, the specific surface area was 185 m ² / g, the pore volume within the pore diameter range of ² to 60 nm was 0.415 mL / g, the center pore diameter Was 7.9 nm.

[Preparation of hydrocracking catalyst]
1078 g of USY zeolite (HSZ-350HUA manufactured by Tosoh Corporation) having a SiO ₂ / Al ₂ O ₃ ratio of 10.5, a lattice constant of 2.439 nm, and a specific surface area of 650 m ² / g was alumina powder (alumina manufactured by SASOL). Pural SB) mixed with 1,303 g, added with 500 mL of 4.0% by weight dilute nitric acid solution and 875 g of ion-exchanged water, kneaded, extruded into a columnar shape (pellet) having a cross-sectional shape of a cross section, and at 130 ° C. for 6 hours. After drying, it was calcined at 600 ° C. for 2 hours to obtain a carrier.

  150 g of this carrier was spray impregnated with an aqueous solution of 26.24 g of ammonium molybdate and dried at 130 ° C. for 6 hours, and then spray-impregnated with an aqueous solution of 26.06 g of nickel nitrate and dried at 130 ° C. for 6 hours. Next, the catalyst B for hydrocracking was obtained by calcining at 500 ° C. for 30 minutes under an air stream. The composition of catalyst B was 7.1% by weight of Mo, 3.0% by weight of Ni, 15.8% by weight of Si, and 23.5% by weight of Al.

When the pore characteristics of this catalyst B were measured by a nitrogen gas adsorption method, the specific surface area was 387 m ² / g, the pore volume in the pore diameter range of ² to 60 nm was 0.543 mL / g, the center pore diameter Was 9.6 nm. Further, this catalyst B had a stable diameter of 1.2 mm, an average length of 4.0 mm, an average side surface crushing strength of 12.0 kgf, and a bulk density of 0.688 g / cm ³ .

(Examples 1 and 2)
[Preparation of desulfurized oil]
Catalyst A as a hydrorefining catalyst is charged into a hydrorefining reactor, reaction pressure = 5.0 MPa, LHSV = 1.0 hr ⁻¹ , hydrogen / feed oil ratio = 1,400 NL / L, reaction temperature = 280 ° C. Under conditions, hydrorefining treatment of raw material oil A (catalytic cracking light oil: LCO) was performed. Commercially available pure hydrogen was used as hydrogen, and it was allowed to flow through without being recycled. During the hydrorefining treatment, the refined oil obtained in a steady state was recovered in a drum in its entirety, and all hydrogen gas was discharged out of the system. Further, in order to remove hydrogen sulfide dissolved in the hydrorefined oil, nitrogen bubbling treatment (20 ° C., 24 hours, 100 mL / min.) Was performed to obtain a refined oil (raw oil B). Properties of the raw material oil A and the raw material oil B are shown in Table 1.

Next, catalyst B was used as the hydrocracking catalyst, reaction pressure = 3.0 MPa, LHSV = 1.0 hr ⁻¹ , hydrogen / raw oil ratio = 1,400 NL / L, reaction temperature = 320 ° C. (Example 1) The feedstock B was hydrocracked at 350 ° C. (Example 2). Since hydrogen was made of commercially available pure hydrogen and flowed through one-through without recycling, the hydrogen sulfide concentration and ammonia concentration contained in the hydrogen gas introduced into the reactor were both below the detection limit (0.01 mol% or less). there were. Properties of the hydrocracked product oil obtained as a result of the reaction are shown in Table 2. In Table 2, the conversion rate of 215 ° C. or higher fraction is a value obtained by the following formula.

215 ° C. or higher fraction conversion (%) = 100−215 ° C. or higher fraction in product oil (volume%) / 215 ° C. or higher fraction in feed oil A (volume%) × 100

Table 2 also shows the ratio of the ratio of carbon constituting the aromatic ring in the hydrocracked product oil to the ratio of carbon constituting the aromatic ring in the feedstock oil A (catalytic cracking light oil) (aromatic ring carbon residual ratio). did. In Table 2, the numerical value (volume%) of each hydrocarbon fraction is shown as a ratio based on the feedstock A (100 volume%).

(Comparative Examples 1 and 2)
The hydrorefining reactor is filled with catalyst A and the hydrocracking reactor with an equal amount of catalyst B, and catalytic cracking gas oil (raw oil A) is used as the raw oil. The reaction pressure is 3.0 MPa, LHSV 0.5 hr ⁻¹ , Hydrogen / raw oil ratio 1,400NL / L, hydrorefining reaction temperature 280 ° C, hydrocracking reaction temperature 320 ° C (Comparative Example 1), hydrocracking reaction temperature 350 ° C (Comparative Example 2) The reaction was performed in substantially the same manner as in Example 1 and Example 2. However, as for hydrogen, commercially pure hydrogen is supplied to the hydrorefining reactor, and the hydrorefined oil and effluent gas are directly introduced into the hydrocracking reactor without removing the gas generated in the hydrorefining reactor. , I did not recycle it, and let it flow through. At this time, the hydrogen sulfide concentration contained in the gas introduced into the hydrocracking reactor was 0.049 mol%, and the ammonia concentration was 0.021 mol%. Table 2 shows the properties of the product oil and the aromatic hydrocarbon composition obtained as a result of the reaction.

,
(Examples 3 and 4)
Tests were performed in the same manner as in Example 1 and Example 2, respectively, except that the hydrogenolysis reaction pressure was 5.0 MPa. The results are shown in Table 3.

(Comparative Examples 3 and 4)
Similarly, the test was performed in the same manner as Comparative Example 1 and Comparative Example 2, respectively, except that the hydrogenolysis reaction pressure was 5.0 MPa. The results are shown in Table 3.

(Examples 5 and 6)
Tests were performed in the same manner as in Example 1 and Example 2 except that the reaction pressure for hydrocracking was 7.0 MPa. The results are shown in Table 4.

(Comparative Examples 5 and 6)
Similarly, the test was performed in the same manner as Comparative Example 1 and Comparative Example 2 except that the reaction pressure for hydrocracking was 7.0 MPa. The results are shown in Table 4.

(Examples 7 and 8)
1,202 g of NH ₄ -Y type zeolite (HSZ-341NHA manufactured by Tosoh Corporation) having a SiO ₂ / Al ₂ O ₃ ratio of 6.9, a lattice constant of 2.452 nm, and a specific surface area of 700 m ² / g was used, and alumina was used. Catalyst C was obtained in the same manner as Catalyst B, except that 1,202 g of powder (UOP Alumina Versal 250) was used.

When the pore characteristics of this catalyst C were measured by a nitrogen gas adsorption method, the specific surface area was 438 m ² / g, the pore volume in the pore diameter range of ² to 60 nm was 0.470 mL / g, the center pore diameter Was 6.1 nm. Further, the catalyst C had a stable diameter of 1.2 mm, an average length of 4.0 mm, an average side surface crushing strength of 12.0 kgf, and a bulk density of 0.668 g / cm ³ .
The test was performed in exactly the same manner as Example 3 and Example 4, respectively, except that Catalyst C was used instead of Catalyst B. The results are shown in Table 5.

  The apparatus and method for measuring the physical properties of the catalyst used in the above Examples and Comparative Examples, and the method for analyzing the properties of the raw material oil and the product oil are shown below.

  For measurement of pore characteristics (specific surface area, pore volume in the range of 2 to 60 nm pore diameter, central pore diameter) by a nitrogen gas adsorption method, an ASAP2400 type measuring instrument manufactured by Micromeritics was used.

  A TH-203CP tablet breaking strength measuring device manufactured by Toyama Sangyo Co., Ltd. was used to measure the side crushing strength of the sample. The measurement probe used was a circular probe having a 5 mm diameter tip. The measurement sample was pressed against the center of the side surface of the columnar sample, and the pressure at which the sample was broken was measured. An average value of 20 samples extracted and measured at random was defined as an average side crushing strength.

  The density was measured by the vibration type density test method of JIS K 2249, and the distillation property was measured by the atmospheric pressure distillation test method of JIS K 2254.

The aromatic ring constituent carbon ratio was measured using a JSX GSX270 nuclear magnetic resonance apparatus using deuterated chloroform as a solvent and tetramethylsilane (0 ppm) as an internal standard. Quantification of aromatic ring carbon and aliphatic carbon for each carbon species classification uses ¹ H-gated decoupling method, data points 32,768 points, observation frequency region width 27,027 Hz, pulse width 2 μs, pulse waiting The measurement was performed at time 30S and the number of integrations of 2,000, and was calculated from the integral ratio of the signal of the Fourier-transformed spectrum. In the obtained spectrum shift value, those in the range of 120 to 150 ppm were attributed to aromatic carbon and expressed as mol% with respect to the total carbon.

  The composition of 1-ring aromatic hydrocarbons (alkylbenzenes) (benzene, toluene, xylenes) and the composition of 1.5-ring aromatic hydrocarbons (tetralins) were measured using a hydrocarbon total component analyzer manufactured by Shimadzu Corporation. Measured and calculated according to JIS K2536.

  Aromatic compound type analysis (ring analysis) is performed using a high performance liquid chromatograph in accordance with JPI-5S-49-97 of the Petroleum Society, using normal hexane for the mobile phase and RI for the detector. did.

  The sulfur content was measured using a fluorescent X-ray method in the high concentration region and a microcoulometric titration method in the low concentration region according to the sulfur content test method of JIS K2541. The nitrogen content was measured using a chemiluminescence method according to the nitrogen content test method of JIS K 2609.

  As shown in Table 2 to Table 5, as in Examples 1 to 8, by selecting an appropriate hydrorefining oil treatment method, the impurities in the gas produced in the hydrorefining reactor are not removed ( Compared to Comparative Examples 1 to 6), the desired monocyclic aromatic hydrocarbons (alkylbenzenes), particularly high-value-added BTX fractions such as benzene and toluene, can be obtained in high yields and can be reacted at low temperatures. As a result, it is possible to extend the life of the catalyst by suppressing the formation of undesirable coking and the like. In addition, it is possible to reduce impurities such as sulfur and nitrogen.

Claims (2)

In the first step for refining heavy hydrocarbon oil containing polycyclic aromatic hydrocarbons, in the second step for gas-liquid separation of the effluent fluid generated in the first step and for reducing impurities in the gas, and in the second step A method for producing alkylbenzenes (single-ring aromatic hydrocarbons) comprising a third step of hydrocracking the obtained refined oil, wherein the heavy hydrocarbon oil has a content of one-ring aromatic hydrocarbon of 10 volumes. %, The ratio of carbon constituting the aromatic ring to the total carbon (aromatic ring constituting carbon ratio) is 35 mol% or more, the 10% distillation temperature in distillation properties is 100 to 230 ° C., 90% distillation temperature is 230-600 ° C., and in a third step, the refined oil, the gas from which impurities are reduced in the second step, by supplying the full threshold hydrogen gas, or without supplying the hydrogen sulfide 0 0.06 mol% or less, and ammonia is 0.0 Hydrocracking catalyst in which at least one metal component selected from Group 6 and Group 8 of the Periodic Table is supported on a carrier comprising a composite oxide and a binder that binds the composite oxide in the presence of hydrogen at a mol% or less The reaction temperature is 200 to 450 ° C., the reaction pressure is 2 to 8 MPa, the liquid space velocity (LHSV) is 0.1 to 10.0 h ⁻¹ , and the hydrogen / hydrocarbon ratio (volume ratio) is 100 to 5,000 NL / L. To convert at least 10% by volume of a fraction having a boiling point of 215 ° C. or higher contained in a heavy hydrocarbon oil into a fraction having a boiling point of less than 215 ° C., and containing 10% by volume or more of a monocyclic aromatic hydrocarbon A process for producing alkylbenzenes, characterized in that a cracked product oil is obtained.
  The alkylbenzenes according to claim 1, wherein the ratio of the aromatic ring constituent carbon ratio of the hydrocracked product oil to the aromatic ring constituent carbon ratio of the heavy hydrocarbon oil (aromatic ring carbon residual ratio) is 0.5 or more. Manufacturing method.