JP2017080738A - Catalyst for producing conjugated diolefin and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a molded catalyst capable of improving hardness and improving the long-term stability of the reaction in the reaction for producing a conjugated diolefin from a mixed gas containing a monoolefin having 4 or more carbon atoms and molecular oxygen by catalytic oxidation dehydrogenation; and a method for producing the same.SOLUTION: There is provided a catalyst for producing a conjugated diolefin from a mixed gas containing a monoolefin having 4 or more carbon atoms and molecular oxygen by catalytic oxidation dehydrogenation, in which a mineral fibrous inorganic auxiliary is added during preparation.SELECTED DRAWING: None

Description

The present invention relates to a catalyst for producing a conjugated diolefin from a mixed gas containing a monoolefin having 4 or more carbon atoms and molecular oxygen by catalytic oxidative dehydrogenation, and a method for producing the same.

Conventionally, butadiene, which is a raw material for synthetic rubber and the like, has been industrially produced by thermal decomposition and extraction of naphtha fractions. There is a need for a manufacturing method. Therefore, attention has been focused on a method for oxidative dehydrogenation of n-butene from a mixed gas containing n-butene and molecular oxygen in the presence of a catalyst. However, the coke-like substance by the target product and / or reaction by-product is deposited or deposited on the catalyst surface, the inert substance, the reaction tube or the post-process equipment, thereby inhibiting the reaction gas flow in the industrial plant, There is a concern that various troubles such as the blockage of the plant, the shutdown of the plant and the decrease in the yield associated therewith may be caused. For the purpose of avoiding the trouble, generally, in industrial plants, the reaction is stopped before clogging occurs, and a regeneration process is performed in which the coke-like substance is burned and removed by raising the temperature of the clogged portion of the reaction tube or the post-process equipment. However, stopping the reaction that is a steady operation and performing the regeneration treatment leads to a deterioration in economic efficiency in the industrial plant, and therefore it is desired that the production of coke-like substances be suppressed as much as possible.

Furthermore, another problem in the method for producing butadiene is damage to the catalyst. This is unique to the process of producing conjugated diolefins, where the shape of the catalyst changes from a packed catalyst shape to a catalyst piece due to a long-term reaction, that is, fragments, granules, or even powders change in shape or deteriorate (break). There are concerns about the following problems. That is, an increase in pressure loss due to accumulation of damaged catalyst pieces in the reactor, an undesirable side reaction due to the catalyst locally accumulated in the reactor, and contamination of the broken catalyst pieces into the subsequent purification system, etc. The following literatures are known as countermeasures in the prior art.

Patent Document 1 discloses the correlation between the change rate of the outer diameter of the catalyst and the change in strength before and after the reaction. In the tableting method, which is a catalyst molding method of Patent Document 1, the mechanical strength of the catalyst is increased, while the catalyst active component is molded so as to be densely aggregated. / Or the point that coke-like substances are likely to deposit compared to catalysts formed by other molding methods, the heat of reaction is likely to accumulate inside the catalyst, the yield is reduced, and the reaction runaway occurs, and the production of the catalyst itself. The bad point is the problem. Patent Document 2 discloses the correlation between the crushing rate in the packed catalyst and the amount of coke-like substance produced, but there is no disclosure regarding the catalyst or reaction conditions for suppressing the crushing rate in the long-term reaction.

As a means for solving the damage of the catalyst, there is an improvement in the hardness of the catalyst itself. Conventionally, as a mechanical strength evaluation method used by those skilled in the art, the degree of abrasion described later can be mentioned. This is a physical property value indicating the degree of breakage against impact at the time of catalyst filling, and is a method for evaluating mechanical strength. The following problems are listed. In other words, since the mechanical load applied to the catalyst is low in the evaluation of the degree of abrasion, even a catalyst having a good degree of abrasion was damaged by a long-term reaction as described later. On the other hand, in the hardness evaluation using a tension / compression tester, the correlation with the damage of the catalyst due to the long-term reaction can be significantly confirmed as will be described later, so it is more severe than the conventional evaluation of mechanical strength. And suitable physical property evaluation can be performed. Further, as will be described later, even a catalyst with a good degree of wear is found to have a low hardness and is damaged by a long-term reaction, and a physical property evaluation method that correlates with the damage of the catalyst due to a long-term reaction has not been known.
The following documents are known as methods for improving the general mechanical strength of the molded catalyst.

Patent Documents 3 to 9 all relate to a catalyst for adding an organic auxiliary agent and / or an inorganic auxiliary agent having a specific particle size distribution, fiber length, acid strength, etc., or a method for producing the same, and mechanical strength. This evaluation method corresponds to the pulverization rate by filling and the evaluation of the degree of wear, and the effect on the improvement in hardness is unknown. That is, in the molded catalyst, particularly the supported molded catalyst, the knowledge about the kind and the addition amount of the auxiliary agent that improves the hardness among mechanical strengths is not described in Patent Documents 3 to 9, and is not known to those skilled in the art. .

Assuming that the catalyst is a ceramic material, as a method for improving the hardness in addition to the addition of the inorganic auxiliary agent, as in Non-Patent Document 1, control of the pore structure can be mentioned. The failure of the catalyst is considered to be caused by the stress inside the catalyst in the long-term reaction or regeneration treatment, and it can be estimated that the stress increases around the pores, leading to the failure. That is, it is preferable to reduce the pores in order to suppress the breakage of the catalyst. However, Non-Patent Document 1 is not publicly known because there is no description of improving the hardness without adding any organic auxiliary in the supported molded catalyst.

In addition, from the viewpoint of economic efficiency in an industrial plant, it is naturally important that butadiene which is the target product can be obtained in a high yield. A low butadiene yield means a relatively high by-product yield, but in this case a higher performance purification system is required to obtain high purity butadiene as the final product in an industrial plant. Therefore, there is a concern that the cost of these facilities will increase. There is a concern that an undesirable side reaction occurs due to the addition of an auxiliary agent for improving the hardness. That is, there has been a demand for the development of a catalyst that does not decrease the amount of butadiene produced or increase the amount of by-product produced, and suppresses damage to the catalyst due to a long-term reaction.

JP 2011-241208 A JP 2012-046509 A Japanese Patent No. 3313863 Japanese Patent No. 4863436 JP 2002-273229 A Japanese Patent No. 5388897 International Publication No. 2012/036038 Pamphlet Japanese Patent No. 5628936 Japanese Patent Laid-Open No. 07-16463

Noboru Miyata, Hiroshi Kanno, “Materials” 32, 354, P102-108

The present invention relates to a catalyst capable of improving the long-term stability of a reaction and improving the hardness in a reaction for producing a conjugated diolefin by catalytic oxidative dehydrogenation from a mixed gas containing a monoolefin having 4 or more carbon atoms and molecular oxygen. It aims at providing the manufacturing method.

As a result of intensive studies to solve the above problems, the present inventor can improve the hardness without decreasing the yield of the conjugated diolefin as the target product by adding a mineral fibrous inorganic auxiliary, It has been found that damage to the catalyst due to a long-term reaction can be remarkably suppressed and the above problems can be solved, and the present invention has been completed.

The present invention has the following features (1) to (9) alone or in combination. That is, the present invention
(1) A catalyst for producing a conjugated diolefin by a catalytic oxidative dehydrogenation reaction from a mixed gas containing a monoolefin having 4 or more carbon atoms and molecular oxygen, comprising a composite metal oxide and a mineral fibrous inorganic auxiliary A molded catalyst for producing conjugated diolefin, characterized by molding
(2) The molded catalyst for conjugated diolefin production according to (1), characterized by satisfying the condition of the following formula (A):
0.1 ≦ R (= La / Dc) ≦ 12 (A)
(In the formula, La is the average fiber length of the mineral fibrous inorganic auxiliary, and Dc is the average particle diameter of the pre-fired powder obtained by the pre-fire step).
(3) The molded catalyst for conjugated diolefin production according to (1) or (2), which does not contain an organic auxiliary agent,
(4) The molded catalyst for conjugated diolefin production according to any one of (1) to (3), wherein the composite metal oxide satisfies the following composition formula (D):
_{Mo 12 Bi a Fe b Co c} Ni d X e Y f Z g O h ···· (D)
(In the formula, X represents at least one element of an alkali metal selected from lithium, sodium, potassium, rubidium, and cesium, and Y represents at least one element of an alkaline earth metal selected from magnesium, calcium, strontium, and barium. Z represents at least one element selected from lanthanum, cerium, praseodymium, neodymium, samarium, eurobium, antimony, tungsten, lead, zinc, cerium, thallium, and a, b, c, d, e, f and g represent atomic ratios of bismuth, iron, cobalt, nickel, X, Y and Z, respectively, with respect to molybdenum 12, and 0.3 <a <3.5, 0.6 <b <3.4, 5 <c <8, 0 <d <3, 0 <e <0.5, 0 ≦ f ≦ 4.0, 0 ≦ g ≦ 2.0, and h satisfies the oxidation state of other elements. Is a numerical value to be.),
(5) A catalyst for producing a conjugated diolefin from a mixed gas containing a monoolefin having 4 or more carbon atoms and molecular oxygen by catalytic oxidative dehydrogenation, comprising a composite metal oxide and a mineral fibrous inorganic auxiliary The supported molded catalyst for producing conjugated diolefin according to any one of (1) to (4), characterized in that is supported on a carrier,
(6) The method for producing a conjugated diolefin production catalyst according to any one of (1) to (5), comprising the following steps:
Step (A1): A mixed solution or slurry containing a compound containing each metal of the composite metal oxide is prepared under conditions of 20 ° C. or higher and 90 ° C. or lower, and the mixed solution or the slurry is dried to obtain a dried product. Process,
Step (A2): a step of pre-baking the dried body obtained in step (A1) to obtain a pre-baked powder,
Step (A3): a step of molding the pre-fired powder obtained in Step (A2) and the mineral fibrous inorganic auxiliary to obtain a molded body,
Step (A4): A step of subjecting the molded body obtained in Step (A3) to main firing to obtain a conjugated diolefin production catalyst,
(7) The method for producing a shaped catalyst for conjugated diolefin production according to (6), wherein the pre-calcination temperature is 200 ° C. or more and 600 ° C. or less, and the main calcination temperature is 200 ° C. or more and 600 ° C. or less,
(8) It has a molding step of coating a carrier with a composite metal oxide and a mineral fibrous inorganic auxiliary together with a binder, and the loading ratio of the catalyst active component is 20 wt% or more and 80 wt% or less, and the average particle size of the catalyst The method for producing a supported molded catalyst for conjugated diolefin production according to (6) or (7), wherein the diameter is 3.0 mm or more and 10.0 mm or less,
(9) The method for producing a shaped catalyst according to any one of (6) to (8), wherein no organic auxiliary is used in all production steps,
About.

According to the present invention, a catalyst having high hardness that can be used in a reaction for producing a conjugated diolefin by catalytic oxidative dehydrogenation from a mixed gas containing a monoolefin having 4 or more carbon atoms and molecular oxygen is obtained. Since damage to the catalyst is suppressed in the reaction, a catalyst having long-term stability and a method for producing the catalyst can be provided.

It can be used in a reaction for producing a conjugated diolefin from a mixed gas containing a monoolefin having 4 or more carbon atoms and molecular oxygen by catalytic oxidative dehydrogenation, preferably catalytic oxidation from a mixed gas containing n-butene and molecular oxygen. A catalyst that can be used in a reaction for producing butadiene by a dehydrogenation reaction and a method for producing the catalyst, and a method for producing the conjugated diolefin according to the present invention in which a mineral fibrous inorganic auxiliary agent is added and molded will be described below.

In the present invention, n-butene means a single component gas or a mixed gas containing at least one component of 1-butene, trans-2-butene, cis-2-butene, and isobutylene. Means 1,3-butadiene.

The mineral fibrous inorganic auxiliary used in the catalyst of the present invention is the above-mentioned naturally produced crystalline and / or amorphous inorganic substance that does not burn and do not undergo glass transition mainly even at a heat treatment of 600 ° C. It is an inorganic material itself, or any fibrous or rod-like auxiliary agent prepared by processing by cutting or cleaving below the glass transition temperature of the inorganic material. . Mineral fibrous inorganic auxiliaries remain in the main firing step, which will be described later, and thus have a role of linking the composite metal oxides (pre-fired powders). The effect of suppressing occurs. In the present invention, the material of the mineral fibrous inorganic auxiliary agent is not particularly limited. For example, any sulfide mineral, oxide mineral, halogenated mineral, inorganic acid salt mineral, organic mineral, etc., alone or in combination, has a glass transition temperature or higher. Of these, those having a Mohs hardness of 2 or more are preferred. Of these, inorganic silicate minerals are preferred, silicate minerals are more preferred, and calcium silicate, ie wollastonite (wollastonite), has hardness. It is most preferable from the viewpoint of the improvement effect and the manufacturing cost. Moreover, it becomes suitable at the point which becomes inactive with respect to a catalytic reaction by performing an acid treatment, an alkali treatment, a silane treatment, etc. individually or in combination with respect to a mineral fibrous inorganic auxiliary agent.

Furthermore, the average fiber length of the mineral fibrous inorganic auxiliary agent preferably satisfies the condition represented by the following formula (A), and most preferably satisfies the condition represented by the following formula (B). Mineral fibrous inorganic auxiliaries are easily available from, for example, Keiwa Furnace Co., Ltd., Hayashi Kasei Co., Ltd. and the like. The average particle size of the mineral fibrous inorganic auxiliary is preferably 0.1 μm to 100 μm, and more preferably 1 μm to 50 μm. The average fiber length of the mineral fibrous inorganic auxiliary is preferably 1 μm to 4000 μm, more preferably 7 μm to 700 μm.
0.1 ≦ R (= La / Dc) ≦ 12 (A)
4 ≦ R (= La / Dc) ≦ 9.5 (B)
(In the formula, La is the average fiber length of the mineral fibrous inorganic auxiliary, and Dc is the average particle diameter of the composite metal oxide.)

In the present invention, the average particle diameter of the composite metal oxide and the organic auxiliary is calculated by, for example, the following method. Although there is no restriction | limiting in particular as an apparatus, For example, various samples are introduce | transduced into a cell using purified water as a dispersion medium using LMS-2000e by Nishiyama Seisakusho, and the scattered light intensity is measured as about 4.0 to 6.0. The average particle size is calculated from the particle size distribution obtained as a percentage by mass. The average particle size of the composite metal oxide is preferably 1 μm to 500 μm, and more preferably 10 μm to 100 μm.

In the catalyst of the present invention or the production method thereof, it is preferable that no organic auxiliary is added or used.

The composite metal oxide in the present invention preferably satisfies the following composition formula (D).
_{Mo 12 Bi a Fe b Co c} Ni d X e Y f Z g O h ···· (D)
(In the formula, X represents at least one element of an alkali metal selected from lithium, sodium, potassium, rubidium, and cesium, and Y represents at least one element of an alkaline earth metal selected from magnesium, calcium, strontium, and barium. Z represents at least one element selected from lanthanum, cerium, praseodymium, neodymium, samarium, eurobium, antimony, tungsten, lead, zinc, cerium, thallium, and a, b, c, d, e, f and g represent atomic ratios of bismuth, iron, cobalt, nickel, X, Y and Z, respectively, with respect to molybdenum 12, and 0.3 <a <3.5, 0.6 <b <3.4, 5 <c <8, 0 <d <3, 0 <e <0.5, 0 ≦ f ≦ 4.0, 0 ≦ g ≦ 2.0, and h satisfies the oxidation state of other elements. Is a numerical value to be.)

The raw material of each metal element for obtaining the catalyst of the present invention is not particularly limited, but nitrates, nitrites, sulfates, ammonium salts, organic acid salts, acetates, carbonates containing at least one of each metal element, Carbonates, chlorides, inorganic acids, inorganic acid salts, heteropolyacids, heteropolyacid salts, hydroxides, oxides, metals, alloys, etc., or mixtures thereof can be used. Of these, nitrate raw materials are preferred.

The method for preparing the catalyst of the present invention is not particularly limited, but preferred is a method in which the active component of the catalyst is obtained as a powder and then molded without adding or using an organic auxiliary. Details are described below. To do. In addition, although the order of each process is described as a preferable example below, the order of each process, the number of processes, and the combination of each process for obtaining the final catalyst product are not limited.

Step (A1) Prepare a mixed solution or slurry of the raw material of the preparation and dry catalyst active ingredient, and after passing through steps such as precipitation method, gelation method, coprecipitation method, hydrothermal synthesis method, etc., then dry spray method, evaporation to dryness The dry powder of the present invention is obtained using a known drying method such as a method, a drum drying method or a freeze drying method. This mixed solution or slurry may be water, an organic solvent, or a mixed solution thereof as a solvent, and there is no restriction on the raw material concentration of the active component of the catalyst. Furthermore, the liquid temperature, atmosphere, etc. of this mixed solution or slurry are not limited. There are no particular restrictions on the blending conditions and drying conditions, but an appropriate range should be selected in consideration of the final catalyst performance, mechanical strength, moldability, production efficiency, and the like. Among these, the most preferable in the present invention is that a mixed solution or slurry of the raw material of the active component of the catalyst is formed under conditions of 20 ° C. to 90 ° C., and this is introduced into the spray dryer and the dryer outlet temperature is 70 ° C. To 150 ° C., and the hot air inlet temperature, the pressure inside the spray dryer, and the flow rate of the slurry are adjusted so that the average particle size of the resulting dry powder is 10 μm to 700 μm. In addition, it is also included in the method for producing the catalyst of the present invention that an optional amount of mineral fibrous inorganic auxiliary and / or organic auxiliary described later is added from the preparation of the mixed solution or slurry in this step to the drying. And

Step (A2) Pre-baking The dry powder thus obtained is pre-baked at 200 ° C. to 600 ° C. to obtain the composite metal oxide (pre-baked powder) of the present invention having an average particle size of 10 μm to 100 μm. Can do. In the present invention, the composite metal oxide is sometimes referred to as pre-fired powder. There are no particular restrictions on the firing time and atmosphere during firing, and there are no particular restrictions on the firing method such as a fluidized bed, rotary kiln, muffle furnace, tunnel firing furnace, and the final catalyst performance and machine. Appropriate ranges should be selected in consideration of mechanical strength, formability and production efficiency. Among these, the most preferable method in the present invention is a method in an air atmosphere in a tunnel firing furnace in the range of 300 ° C. to 600 ° C. for 1 hour to 12 hours. In addition, it is also included in the method for producing a catalyst of the present invention to add a mineral fibrous inorganic auxiliary and an organic auxiliary to be described later in an arbitrary amount before or after the preliminary calcination in this step.

Step (A3) Molding In the present invention, the pre-fired powder obtained in this way can be used as a catalyst as it is, but can also be used after molding. The shape of the molded product is not particularly limited, such as a spherical shape, a cylindrical shape, or a ring shape, but it should be selected in consideration of the mechanical strength, the reactor, the production efficiency of the preparation, etc. in the catalyst finally obtained by a series of preparations. . There is no particular limitation on the molding method, but when the carrier, organic auxiliary, mineral fibrous inorganic auxiliary, binder, etc. shown below are added to the pre-fired powder and molded into a cylindrical shape or ring shape, tableting is performed. When forming into a spherical shape using a molding machine or an extrusion molding machine, a molded product is obtained using a granulator or the like. Among these, in the present invention, a method in which the above-mentioned mineral fibrous inorganic auxiliary agent is added to an inert carrier together with a pre-fired powder, and is coated by rolling granulation and supported and molded is preferable.

Known materials such as alumina, silica, titania, zirconia, niobia, silica alumina, silicon carbide, carbides, and mixtures thereof can be used as the material of the carrier, and the particle size, water absorption rate, mechanical strength, each crystal phase There are no particular restrictions on the crystallinity and mixing ratio, and an appropriate range should be selected in consideration of the final catalyst performance, moldability, production efficiency, and the like. The mixing ratio of the carrier and the pre-fired powder is calculated as a loading rate from the following formula based on the charged weight of each raw material.
Support rate (% by weight) = (weight of pre-fired powder used for molding) / {(weight of pre-fired powder used for molding) + (weight of carrier used for molding)} × 100

The amount of the mineral fibrous inorganic auxiliary added is preferably 0.1% to 25% by weight, particularly preferably 0.3% to 10% by weight, and 0.5% by weight based on the weight of the pre-fired powder. To 5% by weight is most preferred. Further, the mineral fibrous inorganic auxiliary agent may be subjected to a pulverization step before molding, and the pulverization method is not particularly limited. For example, a ball mill, a rod mill, a SAG mill, a jet mill, a self-pulverizing mill, a hammer mill , Pellet mill, disk mill, roller mill, high-pressure grinding roll, VSI mill, etc. are used alone or in combination, and the object of grinding may be mineral fibrous inorganic auxiliary agent alone, but added to pre-fired powder and other molding processes The catalyst raw material to be mixed may be used.

In the present invention, the organic auxiliary is an arbitrary powdery, granular, fibrous, or scale-like auxiliary mainly composed of an organic material that is burned down by a heat treatment of 200 ° C. or higher and 600 ° C. or lower. , Part or all of which shall be burnt down, for example, polymers or polymer beads such as polyethylene glycol or various esters, dried products of superabsorbent resin or water-absorbing products with any water absorption rate, various surfactants, flour or refined Examples include various starches such as starch, and crystalline or amorphous cellulose and its derivatives. When the organic auxiliaries are burned out by the main calcination process and voids are formed in the catalyst as described later, when a load is applied to the catalyst, the stress around the catalyst increases, and as a result, the breakage tends to occur. For this reason, it is preferable not to add an organic auxiliary during the production of the catalyst of the present invention. The average particle size of the organic auxiliary agent in the present invention is in the range of 0.001 to 1000 with respect to the average particle size of the pre-fired powder.

Here, the binder in the present invention is a liquid composed of a single group or a combination of compounds having a molecular diameter of 0.001 or less with respect to the average particle diameter of the pre-fired powder. Such a thing is mentioned. That is, it is a liquid organic solvent, an organic dispersion, a water-soluble organic solvent, and a mixture of these with water in any proportion, and although there is no particular limitation, an aqueous solution of polyhydric alcohol such as glycerin or ion-exchanged water Further, ion-exchanged water is more preferable from the viewpoint of moldability. Since the binder contains water or an organic substance, part or all of the binder is burned out in the main firing step described later. In general, the molecular diameter of the organic substance used in the binder is sufficiently small compared to the average particle size of the pre-calcined powder. Therefore, even if a binder is used, it is necessary to form voids in the catalyst such as an organic auxiliary. It does n’t come. In addition, by using the catalyst raw material solution for the binder, it is possible to introduce the element into the outermost surface of the catalyst in a mode different from the step (A1).

In the support molding method by coating, the amount of the binder used is preferably 2 to 60 parts by weight, more preferably 10 to 50 parts by weight with respect to 100 parts by weight of the pre-fired powder. Since the reaction of the present invention is an oxidative dehydrogenation and an exothermic reaction, the generation of coke-like substances and / or the suppression of the residence are suppressed by the heat dissipation inside the catalyst and further by the efficient diffusion of the produced conjugated diolefin. Therefore, support molding is the most preferable molding method.

Step (A4) Main Firing The pre-fired powder or molded product thus obtained is preferably fired again (main firing) at 200 ° C. or higher and 600 ° C. or lower before being used for the reaction. Regarding the main firing, there is no particular limitation on the firing time and atmosphere at the time of firing, and the firing method is not particularly limited, such as a fluidized bed, rotary kiln, muffle furnace, tunnel firing furnace, and the final catalyst performance, mechanical strength, An appropriate range should be selected in consideration of production efficiency. Among these, the most preferable in the present invention is firing in an air atmosphere in a tunnel firing furnace in a temperature range of 300 ° C. to 600 ° C. for 1 hour to 12 hours.

In the present invention, all production steps are all steps from step (A1) to step (A4) alone or in combination until the catalyst of the present invention is obtained from a catalyst raw material. In the present invention, the molding step is a part or all of the step (A3).

The shape and size of the catalyst obtained by the above preparation are not particularly limited, but considering the workability of filling the reaction tube and the pressure loss in the reaction tube after filling, the shape is spherical and the average particle size is The diameter is preferably 3.0 mm to 10.0 mm, and the catalyst active component loading is preferably 20 wt% to 80 wt%.

In the present invention, the degree of wear, which is an index representing mechanical strength, is calculated by the following method. After treating 50 g of the catalyst sample with a rotation rate of 25 rpm and a treatment time of 10 minutes, using a Hayashiri Chemical Co., Ltd. tablet friability tester as the apparatus, the portion that was worn with a standard sieve having an opening of 1.70 mm was sieved and sieved. The remaining catalyst weight is measured and calculated by the following formula. The lower the value of the friability, the better the mechanical strength. A preferable range is, for example, 3% by weight or less, more preferably 1.5% by weight or less, and further preferably 0.5% by weight or less.
Abrasion degree (% by weight) = 100 × [(catalyst weight−catalyst weight remaining on sieve) / catalyst weight]

In the present invention, hardness, which is an index representing mechanical strength, is calculated by the following method. The apparatus is not particularly limited. For example, a tensile compression tester (Technograph TG5kN manufactured by Minebea Co., Ltd.) is used, a dedicated attachment is connected, one catalyst is placed, the load speed is set to 2 mm / min in the compression mode, and the displacement − Obtain a load curve. Immediate evaluation is performed when a mechanical load is continuously applied to the catalyst, and the load drops by 5% or more of the maximum value, or falls by 0.1 kgf or more, or when the catalyst is visually checked for cracks. Stop and let the maximum value of the displacement-load curve be the hardness of the catalyst. This evaluation is carried out with 30 or more catalysts, and the average value is taken as the hardness. In the following examples, the hardness refers to the hardness measured by a tensile compression tester, but the hardness of the present invention is broadly defined regardless of the method, and damage to the catalyst due to a long-term reaction such as the Kaya-ya hardness or Vickers hardness. If it is within the range of hardness evaluation in which a significant correlation is found, it shall be regarded as equivalent to hardness. As an index of mechanical strength, in addition to the average value of the hardness of a plurality of catalysts as described above, a measure of variation in hardness of a plurality of catalysts, for example, a standard deviation assuming that the hardness has a normal distribution, etc. It is also possible to apply a Weibull coefficient or the like when assuming a Weibull distribution, and minimum hardness values of a plurality of catalysts.

The reaction conditions for producing a conjugated diolefin from a monoolefin having 4 or more carbon atoms by the catalyst of the present invention are as follows: 1 vol% to 20 vol% monoolefin, 5 vol% to 20 vol% molecular The reaction bath temperature is in the range of 200 ° C. to 500 ° C. using a mixed gas containing oxygen, 0% to 60% by volume of water vapor, and 0% to 94% by volume of an inert gas such as nitrogen and carbon dioxide. As the reaction pressure, the space velocity (GHSV) of the raw material gas with respect to the catalyst molded body of the present invention is in the range of 350 hr ⁻¹ to 7000 hr ^{−1 at} a pressure of normal pressure to 10 atm. Although there is no restriction | limiting in a fixed bed, a moving bed, and a fluidized bed as a form of reaction, A fixed bed is preferable.

In the present invention, the failure of the catalyst means that the reaction of producing a conjugated diolefin from a monoolefin having 4 or more carbon atoms is allowed to react for a long time in the presence of the catalyst, so that the mechanical strength of the catalyst itself is lowered and the catalyst at the time of filling is reduced. This is a phenomenon in which the shape changes, deteriorates and breaks down (breaks) from the shape of the catalyst to the shape of fragments, and is caused by damage from the inside of the catalyst due to the formation of coke-like substances and / or combustion due to regeneration treatment Damage due to heat or rapid expansion of combustion gas is considered. Damaged catalyst pieces accumulate in the reactor due to damage to the catalyst, leading to increased pressure loss, undesirable reactions due to locally accumulated catalyst in the reactor, and problems such as contamination in the subsequent purification system. Is concerned.

In the present invention, the mechanical strength is a measurement obtained by strength evaluation by some physical or mechanical load on one or a plurality of catalysts, such as the above-mentioned degree of wear and hardness, and the packing powder rate described in Patent Document 3, etc. It is a general term for the results.

In the present invention, the coke-like substance is generated by at least one of a reaction raw material, a target product or a reaction by-product in a reaction for producing a conjugated diolefin, and details of its chemical composition and generation mechanism are unknown. However, by depositing or adhering to the catalyst surface, inert substances, reaction tubes and post-process equipment, various factors such as obstructing the reaction gas flow, blocking the reaction tubes, and shutting down the reactions associated with them, especially in industrial plants. Shall be the causative substance that causes trouble. Furthermore, for the purpose of avoiding the above-mentioned trouble, industrial plants generally stop the reaction before clogging occurs, and regenerate the coke-like substances by burning and removing them by raising the temperature of the clogged parts such as reaction tubes and post-processing equipment. I do. Moreover, as a production | generation mechanism of a coke-like substance, the following is assumed, for example. That is, when using a composite metal oxide catalyst containing molybdenum, it is caused by polymerization of various olefins and condensation of high-boiling compounds starting from a molybdenum compound that sublimates and precipitates in the reactor, and in the catalyst and reactor. Production of high-boiling compounds by the polymerization of various olefins and condensation of high-boiling compounds starting from abnormal acid-base points and radical formation points, and production of high-boiling compounds by Diels-Alder reaction with conjugated diolefins and other olefinic compounds, and local in the reactor In addition to the above, there are those caused by condensation at a low temperature, and various other mechanisms are known.

As shown below, the catalyst of the present invention preferably has a certain degree of abrasion and a certain hardness at least before the start of the reaction. Conventionally, as a mechanical strength evaluation method used by those skilled in the art, the degree of abrasion described later can be mentioned. This is a physical property value indicating the degree of breakage against impact at the time of catalyst filling, and is a method for evaluating mechanical strength. The following problems are listed. In other words, since the mechanical load applied to the catalyst is low in the evaluation of the degree of wear, even a catalyst with a good degree of wear as described later may be damaged by a long-term reaction. On the other hand, the tensile and compression tester can apply a high mechanical load suitably for the problem of the present invention in the hardness evaluation, and significantly confirms the correlation with the damage of the catalyst due to the long-term reaction as described later. This is a physical property evaluation method that is stricter and more suitable than the conventional evaluation of mechanical wear, which is an evaluation of mechanical strength.

The degree of abrasion is determined by the type and amount of various strength improvers and binders added during molding, or combinations thereof, the atomic ratio of the catalyst composition, the phase form and ratio of each crystal phase, and the formulation process and drying process. The particle size is influenced by various preparation steps such as the diameter, geometric structure, and aggregated form of secondary particles of the catalytically active component to be used, and the value is preferably 2% by weight or less.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the meaning is exceeded. In the following,% means mol% unless otherwise specified. In the following, the definitions of n-butene conversion, butadiene yield, and TOS are as follows.

n-butene conversion (mol%)
= (Number of moles of reacted n-butene / number of moles of supplied n-butene) × 100
Butadiene yield (mol%)
= (Number of moles of butadiene produced / number of moles of supplied n-butene) × 100
TOS = Mixed gas circulation time (hours)

Example 1
(Preparation of catalyst 1)
800 parts by weight of ammonium heptamolybdate was completely dissolved in 3000 parts by weight of pure water heated to 80 ° C. (Mother solution 1). Next, 11 parts by weight of cesium nitrate was dissolved in 124 ml of pure water and added to the mother liquor 1. Next, 275 parts by weight of ferric nitrate, 769 parts by weight of cobalt nitrate and 110 parts by weight of nickel nitrate were dissolved in 612 ml of pure water heated to 60 ° C. and added to the mother liquor 1. Subsequently, 165 parts by weight of bismuth nitrate was dissolved in an aqueous nitric acid solution prepared by adding 42 parts by weight of nitric acid (60% by weight) to 175 ml of pure water heated to 60 ° C. and added to the mother liquor 1. This mother liquor 1 was dried by a spray drying method, and the obtained dry powder was pre-fired at 440 ° C. for 5 hours. The pre-fired powder thus obtained (average particle size: 63.2 μm, the atomic ratio calculated from the charged raw materials is Mo: Bi: Fe: Co: Ni: Cs = 12: 1.7: 1.8: 7. 0: 1.0: 0.15) 5% by weight of crystalline cellulose (average particle size: 89.3 μm) and 3% by weight of wollastonite (average fiber diameter: 12 μm, average fiber length: 250 μm) is added and mixed well, and then 33% by weight glycerin solution is used as a binder in the rolling granulation method, and 33% by weight of the pre-fired powder is used. The support was molded into a spherical shape so as to be 50% by weight. The spherical molded product thus obtained was calcined at 500 ° C. for 5 hours to obtain the catalyst 1 of the present invention. Catalyst 1 had a friability of 0.13% by weight and a hardness of 2.7 kgf (26.5 N).

Example 2
(Preparation of catalyst 2)
A catalyst was prepared under the same conditions as catalyst 1 except that 5% by weight of crystalline cellulose was not added to the pre-fired powder obtained in Example 1 to obtain catalyst 2 of the present invention. It was. Catalyst 2 had a friability of 0.42% by weight and a hardness of 7.2 kgf (70.6 N).

Example 3
(Preparation of catalyst 3)
5% by weight of crystalline cellulose (average particle size: 89.3 μm) and 3% by weight of wollastonite (average fiber diameter: 40 μm, average fiber length) with respect to the pre-fired powder obtained in Example 1 The catalyst 3 of the present invention was obtained under the same conditions as for the catalyst 1 except that 600 μm) was added. The degree of abrasion of the catalyst 3 was 0.22% by weight, and the hardness was 3.1 kgf (30.4 N).

Example 4
(Preparation of catalyst 4)
5% by weight of crystalline cellulose (average particle size: 89.3 μm) and 3% by weight of wollastonite (average fiber diameter: 12 μm, average fiber length) with respect to the pre-fired powder obtained in Example 1 The catalyst 4 of the present invention was obtained under the same conditions as for the catalyst 1 except that 156 μm) was added. Catalyst 4 had a friability of 0.53% by weight and a hardness of 2.7 kgf (26.5 N).

Example 5
(Preparation of catalyst 5)
5% by weight of crystalline cellulose (average particle size: 89.3 μm) and 3% by weight of wollastonite (average fiber diameter: 2 μm, average fiber length) with respect to the pre-fired powder obtained in Example 1 The catalyst 5 of the present invention was obtained under the same conditions as for the catalyst 1, except that 5 μm) was added. The degree of abrasion of the catalyst 5 was 0.07% by weight, and the hardness was 2.5 kgf (24.5 N).

Example 6
(Preparation of catalyst 6)
5% by weight of crystalline cellulose (average particle size: 89.3 μm) and 3% by weight of wollastonite (average fiber diameter: 2 μm, average fiber length) with respect to the pre-fired powder obtained in Example 1 The catalyst 6 of the present invention was obtained under the same conditions as for the catalyst 1, except that 8 μm) was added. The abrasion loss of the catalyst 6 was 0.19% by weight, and the hardness was 2.7 kgf (26.5 N).

Example 7
(Preparation of catalyst 7)
5% by weight of crystalline cellulose (average particle diameter: 89.3 μm) and 3% by weight of wollastonite (average fiber diameter: 50 μm, average fiber length) with respect to the pre-fired powder obtained in Example 1 The catalyst 7 of the present invention was obtained under the same conditions as the catalyst 1 except that 840 μm) was added. The degree of abrasion of the catalyst 7 was 0.27% by weight, and the hardness was 2.5 kgf (24.5 N).

Example 8
(Preparation of catalyst 8)
5% by weight of crystalline cellulose (average particle diameter: 89.3 μm) and 3% by weight of wollastonite (average fiber diameter: 50 μm, average fiber length) with respect to the pre-fired powder obtained in Example 1 The catalyst 8 of the present invention was obtained under the same conditions as in the catalyst 1 except that 620 μm) was added. The abrasion loss of the catalyst 8 was 0.32% by weight, and the hardness was 2.7 kgf (26.5 N).

Example 9
(Preparation of catalyst 9)
5% by weight of crystalline cellulose (average particle diameter: 89.3 μm) and 3% by weight of wollastonite (average fiber diameter: 50 μm, average fiber length) with respect to the pre-fired powder obtained in Example 1 The catalyst 9 of the present invention was obtained under the same conditions as for the catalyst 1 except that 240 μm) was added. The degree of wear of the catalyst 9 was 0.28% by weight, and the hardness was 2.7 kgf (26.5 N).

Comparative Example 1
(Preparation of catalyst 10)
5% by weight of crystalline cellulose (average particle size: 89.3 μm) was added to the pre-fired powder obtained in Example 1 and mixed well, and then 33 as a binder by rolling granulation. A catalyst 10 for comparison was obtained by preparing a catalyst under the same conditions as in the catalyst 1 except that 40% by weight of the glycerin solution by weight was used with respect to the pre-fired powder. The abrasion loss of the catalyst 10 was 0.31% by weight, and the hardness was 1.6 kgf (15.7 N).

Comparative Example 2
(Preparation of catalyst 11)
5% by weight of crystalline cellulose (average particle size: 89.3 μm) and 3% by weight of talc (average particle size: 57 μm) were added to the pre-fired powder obtained in Example 1, and sufficient After mixing, a catalyst was prepared under the same conditions as in Catalyst 1 except that 40% by weight of a 33% by weight glycerin solution was used as a binder in the rolling granulation method with respect to the pre-fired powder. Got. The degree of abrasion of the catalyst 11 was 0.20% by weight, and the hardness was 1.4 kgf (13.7 N).

Comparative Example 3
(Preparation of catalyst 12)
Except that 5% by weight of crystalline cellulose was not added at all to the pre-fired powder obtained in Example 1, and 3% by weight of talc (average particle diameter: 57 μm) was added, A catalyst was prepared under the same conditions as catalyst 1, and a comparative catalyst 12 was obtained. The degree of wear of the catalyst 12 was 0.24% by weight, and the hardness was 1.9 kgf (18.6 N).

Comparative Example 4
(Preparation of catalyst 13)
A catalyst was prepared under the same conditions as in Catalyst 1 except that no auxiliary agent was added to the pre-fired powder obtained in Example 1, and a comparative catalyst 13 was obtained. The degree of wear of the catalyst 13 was 0.48% by weight, and the hardness was 2.3 kgf (22.5 N).

Test example 1
(Coke precipitation reaction)
The reaction of the catalyst 2 obtained in Example 2 was evaluated by the following method. A stainless steel reaction tube was charged with 53 ml of a catalyst, and a gas mixture with a gas volume ratio of 1-butene: oxygen: nitrogen: water vapor = 1: 1: 7: 1 was used under the conditions of GHSV 1200 hr ⁻¹ under normal pressure. The reaction bath temperature was changed so that the butene conversion ratio = 80.0 ± 1.0% was maintained, and the reaction was continued for up to 300 hours of TOS to deposit a coke-like substance on the catalyst. At the outlet of the reaction tube, a liquid component and a gas component were separated by a condenser, and each component in the gas component was quantitatively analyzed by a gas chromatograph equipped with a flame ionization detector and a heat conduction detector. Each data obtained by gas chromatograph was factor corrected, and 1-butene conversion and butadiene selectivity were calculated. Butadiene selectivity at TOS 280 hours was 87.8%.

(Coke combustion reaction)
For the purpose of burning the coke-like substance deposited on the catalyst after the coke deposition reaction, a reaction bath temperature is set to 400 ° C., a mixed gas having a gas volume ratio of oxygen: nitrogen = 1: 3, and a space velocity of 400 hr under normal pressure. ^The coke-like substance was burned at ^-1 for about 10 hours of TOS. The same quantitative analysis as in the coke precipitation reaction was performed, and it was determined that the combustion of the coke-like substance was completed when the amount of CO ₂ and CO produced in the reaction tube outlet gas became zero.

(Damage rate evaluation)
After the coke combustion reaction, the catalyst after the reaction was extracted from the reaction tube and classified with a 3.35 mm sieve. The broken piece and powdered catalyst that fell under the sieve were weighed as catalyst pieces, and the failure rate of the catalyst 2 calculated by the following equation was 0.13 wt%.
Damage rate (% by weight)
= Weight of catalyst piece (g) / weight of packed catalyst before coke deposition reaction (g) x 100

Comparative Test Example 1
In Test Example 1, the damage rate was evaluated by a long-term test under the same reaction conditions except that the catalyst to be evaluated was the catalyst 10 obtained in Comparative Example 1. The failure rate of the catalyst 10 was 1.55% by weight. Butadiene selectivity at TOS 280 hours was 87.1%.

Comparative test example 2
In Test Example 1, the damage rate was evaluated by a long-term test under the same reaction conditions except that the catalyst to be evaluated was the catalyst 12 obtained in Comparative Example 3. The failure rate of the catalyst 12 was 1.86% by weight. Butadiene selectivity at TOS 280 hours was 86.6%.

Comparative test example 3
In Test Example 1, the damage rate was evaluated by a long-term test under the same reaction conditions except that the catalyst to be evaluated was the catalyst 13 obtained in Comparative Example 4. The failure rate of the catalyst 13 was 1.16% by weight. Butadiene selectivity at TOS 280 hours was 87.4%.

Table 1 shows the results of the degree of wear, hardness, and breakage rate in Examples, Comparative Examples, Test Examples, and Comparative Test Examples. As is apparent from Table 1, it can be seen that the hardness is improved by the addition of the mineral fibrous inorganic auxiliary according to the present invention, and the hardness of the catalyst can be further remarkably improved by not adding the organic auxiliary. Furthermore, in the catalyst with improved hardness, the damage rate due to the long-term reaction can be significantly suppressed, suggesting that the catalyst of the present invention can improve the long-term stability of the reaction. In the catalyst 10, although the degree of abrasion was good, the catalyst was damaged due to a long-term reaction. In addition, the comparison between the catalyst 2 and the catalyst 10 shows that the hardness evaluation can be significantly correlated with the damage of the catalyst due to the long-term reaction. It is concluded that That is, although not known to those skilled in the art, it is apparent from the present invention that hardness is suitable as a physical property evaluation method correlated with damage due to long-term reaction, not the degree of abrasion, which is a conventional mechanical strength evaluation method. Became.

Claims (9)

A catalyst for producing a conjugated diolefin from a mixed gas containing a monoolefin having 4 or more carbon atoms and molecular oxygen by catalytic oxidative dehydrogenation, and molding a composite metal oxide and a mineral fibrous inorganic auxiliary A shaped catalyst for producing conjugated diolefins. The molded catalyst for conjugated diolefin production according to claim 1, characterized in that the condition of the following formula (A) is satisfied:
0.1 ≦ R (= La / Dc) ≦ 12 (A)
(In the formula, La is the average fiber length of the mineral fibrous inorganic auxiliary, and Dc is the average particle diameter of the pre-baked powder obtained by the pre-baking step). The shaping | molding catalyst for conjugated diolefin manufacture of Claim 1 or Claim 2 which does not contain an organic adjuvant. The molded catalyst for conjugated diolefin production according to any one of claims 1 to 3, wherein the composite metal oxide satisfies the following composition formula (D):
_{Mo 12 Bi a Fe b Co c} Ni d X e Y f Z g O h ···· (D)
(In the formula, X represents at least one element of an alkali metal selected from lithium, sodium, potassium, rubidium, and cesium, and Y represents at least one element of an alkaline earth metal selected from magnesium, calcium, strontium, and barium. Z represents at least one element selected from lanthanum, cerium, praseodymium, neodymium, samarium, eurobium, antimony, tungsten, lead, zinc, cerium, thallium, and a, b, c, d, e, f and g represent atomic ratios of bismuth, iron, cobalt, nickel, X, Y and Z, respectively, with respect to molybdenum 12, and 0.3 <a <3.5, 0.6 <b <3.4, 5 <c <8, 0 <d <3, 0 <e <0.5, 0 ≦ f ≦ 4.0, 0 ≦ g ≦ 2.0, and h satisfies the oxidation state of other elements. Is a numerical value to be.). A catalyst for producing a conjugated diolefin from a mixed gas containing a monoolefin having 4 or more carbon atoms and molecular oxygen by catalytic oxidative dehydrogenation, comprising a composite metal oxide and a mineral fibrous inorganic auxiliary as a support The supported molded catalyst for producing conjugated diolefin according to any one of claims 1 to 4, which is supported. The manufacturing method of the catalyst for conjugated diolefin manufacturing as described in any one of Claims 1-5 characterized by including the following process:
Step (A1): A mixed solution or slurry containing a compound containing each metal of the composite metal oxide is prepared under conditions of 20 ° C. or higher and 90 ° C. or lower, and the mixed solution or the slurry is dried to obtain a dried product. Process,
Step (A2): a step of pre-baking the dried body obtained in step (A1) to obtain a pre-baked powder,
Step (A3): a step of molding the pre-fired powder obtained in Step (A2) and the mineral fibrous inorganic auxiliary to obtain a molded body,
Step (A4): A step of subjecting the molded body obtained in the step (A3) to main firing to obtain a conjugated diolefin production catalyst. The manufacturing method of the shaping | molding catalyst for conjugated diolefin manufacture of Claim 6 whose temperature of preliminary calcination is 200 degreeC or more and 600 degrees C or less and whose main calcination temperature is 200 degreeC or more and 600 degrees C or less. The carrier has a molding step of coating a composite metal oxide and a mineral fibrous inorganic auxiliary together with a binder, the loading ratio of the catalytically active component is 20% by weight or more and 80% by weight or less, and the average particle size of the catalyst is 3 The method for producing a supported molded catalyst for producing a conjugated diolefin according to claim 6 or 7, wherein the catalyst is 0.0 mm or more and 10.0 mm or less. The manufacturing method of the shaping | molding catalyst of any one of Claim 6 to 8 which does not use an organic adjuvant in all the manufacturing processes.