JP5050466B2 - Propylene production method - Google Patents

Description

  The present invention relates to a method for producing propylene by reacting a raw material mixture containing an olefin having 2 or more carbon atoms and methanol and / or dimethyl ether in the presence of a catalyst comprising a molded product containing a solid acid as an active ingredient. is there.

In naphtha steam cracking, which is commonly practiced as a method for producing propylene, propylene is produced as a co-product of other olefins such as ethylene. In this method, although the yield balance of ethylene and propylene can be changed depending on the operating conditions, there is a limit to the control thereof, and at present, ethylene and propylene are produced in desired yields according to the demands of both. It was impossible.
Further, various thermal decomposition methods such as fluid catalytic cracking have been studied, but none of them significantly changes the yield balance.

  In recent years, a metathesis reaction in which ethylene and 2-butene are reacted and an MTO (methanol to olefins) reaction in which olefin is synthesized from methanol have attracted attention. A method for obtaining propylene from ethylene and methanol is also known as one form of the MTO process, but in this method as well, the yield of propylene based on methanol does not exceed 40% and is sufficiently satisfactory. The yield obtained is not obtained.

On the other hand, the present inventors contacted an olefin having 2 or more carbon atoms and methanol and / or dimethyl ether with a solid acid catalyst under specific conditions to obtain propylene in a higher yield than the conventional method. Developed (Japanese Patent Laid-Open No. 2005-232121).
When industrially producing propylene by catalytic reaction, it is widely adopted to perform a gas phase reaction using a fixed bed, but the solid acid catalyst used for the fixed bed satisfies a sufficient mechanical strength, In addition, it is necessary to express the original performance of the solid acid which is an active ingredient.

However, the present situation is that studies on catalyst molded bodies that exhibit such performance have not been sufficiently conducted so far.
For example, in US Published Patent Publication US-2003-0181777, when performing the above-described cracking reaction of butene in the presence of methanol, zeolite (MTT) pelletized by tableting is used as a solid acid catalyst. No so-called binder is added and the mechanical strength is not sufficient. Moreover, the description about the synthesis method of zeolite itself is not enough, and the composition is not clarified.
Japanese Patent Laying-Open No. 2005-232121 US Published Patent Publication US-2003-0181777

  In the present invention, when propylene is produced by bringing a raw material mixture containing an olefin having 2 or more carbon atoms and methanol and / or dimethyl ether into contact with a catalyst containing a solid acid as an active ingredient, the original performance of the solid acid is effectively improved. It is an object of the present invention to provide a method for efficiently producing propylene using a molded article that can be expressed.

  As a result of intensive studies in order to solve the above problems, the present inventors have found that in a molded body containing a solid acid as an active ingredient, the Na content contained in the molded body affects the reaction results. That is, even if the active ingredients contained in the molded body are the same, it has been found that when the Na content in the molded body is different, the reaction results such as the selectivity of propylene are different. Further, when the compressive strength of the molded product having a Na content within a specific range was changed, the compressive strength was not necessarily high, and it was found that if the compressive strength is too high, the catalyst life is shortened. .

  Based on the above knowledge, the inventors have adjusted the Na content and the compressive strength in the total composition of the molded body in a well-balanced manner, whereby the active ingredient is essentially held in a powder state. The present inventors have found that the performance can be effectively expressed even in a molded body and can be excellent in catalytic activity and durability.

That is, the first gist of the present invention is that a cation is a proton in a method for producing propylene by contacting a raw material mixture containing an olefin having 2 or more carbon atoms and methanol and / or dimethyl ether in the presence of a catalyst. A molded product comprising an aluminosilicate as an active ingredient, wherein a molded product having a Na content of 0.06% by weight or less based on the total weight of the molded product is used as the catalyst, Exist.

  The second gist of the present invention resides in the method for producing propylene according to claim 1, wherein the compact has a compressive strength of 0.2 to 20 MPa.

According to the present invention, a raw material mixture containing an olefin having 2 or more carbon atoms and methanol and / or dimethyl ether is contacted in a gas phase in a reactor in the presence of a catalyst comprising a molded product containing a solid acid as an active component. In the method for producing propylene, propylene can be produced in a high yield by expressing the catalyst performance of the solid acid in the catalyst molded body.
Further, according to the present invention, it is possible to produce propylene that is stable over a long period of time by using a molded catalyst having a solid catalyst as the active component and having a long catalyst life.

  Although the typical form for implementing this invention is demonstrated concretely below, this invention is not limited to the following forms, unless the summary is exceeded.

  The method for producing propylene of the present invention comprises a solid acid as an active ingredient in a method for producing propylene by contacting a raw material mixture containing an olefin having 2 or more carbon atoms and methanol and / or dimethyl ether in the presence of a catalyst. A molded body having a Na content of 0.06% by weight or less based on the total weight of the molded body is used as the catalyst.

In the present invention, the term “molded body (sometimes referred to as a catalyst molded body)” means that particles such as zeolite, which is an active ingredient, are arranged in a size and shape suitable for the intended use. A compound (binder) having a function of binding each other is coexisted, and the binding force between the particles is increased to be strongly aggregated, and the particles are arranged in a desired size and shape. Therefore, when a binder (binder) is not used, it is not desirable because it is difficult to bond firmly. However, as a method of forming a strong molded body without using a binder, hydrothermal heat treatment using silica gel already formed as a raw material is used. There is also a method of synthesizing and converting to zeolite, for example, a method called binderless zeolite described in JP-A-2001-10813.
The molding method is not particularly limited, and examples thereof include granulation, extrusion, and other methods.

[catalyst]
The catalyst used in the present invention consists of a molded body containing a solid acid as an active ingredient.

<Active ingredient>
The solid acid as the active component of the catalyst molded body used in the present invention is not particularly limited as long as it is a solid having a Bronsted acid point or a Lewis acid point. For example, a clay mineral such as kaolin; A material such as clay mineral impregnated / supported with acid such as sulfuric acid and phosphoric acid; complex oxide such as silica alumina and silica titania; acidic ion exchange resin; aluminum phosphate salt; zeolites; Al-MCM41 Known solid acids such as mesoporous silicas such as lamellar zeolite such as ITQ-2 can be arbitrarily used.

Among these solid acid catalysts, those having a molecular sieving effect are preferable.
Examples of such a solid acid include zeolites such as aluminophosphates and aluminosilicates, preferably aluminosilicates.

  The aluminosilicate zeolite may be one in which some or all of the Al atoms constituting the zeolite are substituted with other metal atoms. Such other metal atoms are those of Group 1 to Group 15 of the periodic table, preferably consisting of B, Ga, Fe, Cr, Mn, Zn, Zr, Ti, Co, Ni, and V. One or more selected from the group, more preferably one or more selected from the group consisting of B, Ga, and Fe, most preferably B.

  The molar ratio (Si / Al) between Si and Al of this aluminosilicate-based zeolite is 10 to 4000, preferably 50 to 2000, more preferably 100 to 1500 when it contains no atoms other than Al. It is. When atoms other than Al are included, the molar ratio between Si and atoms other than Al + Al (Si / (atom other than Al + Al)) is 10 to 3000, preferably 20 to 2000, and more preferably. 30-1000.

  These aluminosilicate zeolites include those having exchangeable cation species. Examples of the cation species in this case include protons, alkali elements, and alkaline earth elements, and protons are particularly preferable. In addition, when it contains alkali element Na, when it is set as a molded object, Na content needs to be below the regulation value of this invention mentioned later.

<Zeolite structure>
As the structure of the zeolite as the catalytic active component, those having micropores having a pore diameter of 0.3 to 0.9 nm are preferable. The pore diameter referred to here indicates a crystallographic free diameter of the channels defined by International Zeolite Association (IZA). When the shape of the pore (channel) is a true circle, When the diameter is a pore and the shape of the pore is an ellipse, the short diameter is indicated.
Among them, when expressed by a code having a structure defined by the International Zeolite Association (IZA), for example, AEI, AET, AEL, AFI, AFO, AFS, AST, ATN, BEA, CAN, CHA, DDR, EMT, ERI, EUO, FAU, FER, LEV, LTL, MAZ, MEL, MFI, MOR, MTT, MTW, MWW, OFF, PAU, RHO, STT, TON, etc. are preferable, and among these, MFI, MEL, MOR, MWW, CHA , BEA and FAU are more preferable, and CHA, MFI and MWW are the most preferable among them.
These may be used alone or in combination of two or more.

<Method for preparing catalytically active component>
The method for preparing the catalytically active component used in the present invention is not particularly limited, and it can be prepared by a known method.
With regard to zeolite, the composition can be changed after hydrothermal synthesis by modifications such as ion exchange, dealumination treatment, impregnation and loading.
The catalytically active component used in the present invention may be prepared by any method as long as it has the above-mentioned physical properties and further composition when subjected to the reaction.

<Na content of catalyst molded body>
In the present invention, the catalytically active component is subjected to a reaction as a molded body.
Usually, an active ingredient is used as a molded body by granulating and molding by an after-mentioned method using a substance or binder inactive to the reaction.
In the present invention, a catalyst molded body having a Na content of 0.06% by weight or less is used. When there is much Na content in a catalyst molded object, there exists a tendency which has a bad influence on reaction results, such as the fall of the selectivity of propylene. The smaller the Na content of the catalyst molded body, the better, preferably 0.03% by weight or less, more preferably 0.01% by weight or less (below the detection limit).

In the present invention, the reason why the Na content in the catalyst molded body affects the reaction results is not clear, but is estimated as follows.
When a solid acid zeolite is molded using a binder, it is necessary to sufficiently exhibit the catalytic performance due to the acid sites that the zeolite originally has. However, as a result of investigations by the present inventors, even when the same zeolite was used, the same catalyst performance was not always exhibited when formed into a molded body using various binders. As a result of investigating the cause, it was found that when the amount of Na contained in the molded body is a certain amount or more, the catalyst performance inherent in the zeolite is not expressed. This is due to the fact that Na, which is considered to be contained in the binder, is used in the process of producing a molded product, and the protons that express the acid point of the zeolite are poisoned by ion exchange, thereby reducing the acid properties inherent to the zeolite. This is thought to be due to a decrease in catalyst performance.

  In addition, the analysis method of content of Na in a catalyst molded object and content of other elements is as follows.

(Method of elemental analysis)
Elements other than Si, such as Al and Na, in the sample are quantified by performing ICP analysis (plasma emission analysis) after dissolving the sample that has been dried at 200 ° C. or more for 5 hours or more with hydrofluoric acid.
In addition, the Si element is quantified by performing ICP analysis by dissolving a sample subjected to the same drying treatment in an alkali melt with sodium carbonate in water.

  In order to control the Na content in the catalyst molded body, the Na content contained in the binder to be used is controlled to an appropriate amount when molding the active ingredient. Specifically, various commercially available binders are used. Since there are many different Na contents, it is possible to adopt a method such as selecting appropriately according to the desired Na content. In addition, when the desired Na content is not obtained after molding, it is possible to obtain the desired Na content by subjecting the molded body to ion exchange treatment again and changing Na ions into protons.

<Compressive strength of catalyst compact>
The catalyst molded body used in the present invention preferably has a compressive strength of 0.2 to 20 MPa. When the compression strength of the molded body is too small, the mechanical strength as the molded body is not preferable because it is insufficient, and when it is too large, the catalyst life is reduced, which is not preferable.
The preferable compressive strength of the catalyst molded body is 0.5 MPa or more, particularly 1.2 MPa or more, and 15 MPa or less, particularly 10 MPa or less.

  In addition, the measuring method of the compressive strength of the catalyst molded object of this invention is as follows.

(Compressive strength measurement method)
The measurement and calculation of the compressive strength is performed in accordance with the method described in JIS28841-1993 “Compressive strength”. This is a method of converting the stress (unit: N or gf) at the time of compression obtained by compressing particles at a constant speed into a compressive strength (unit: MPa) according to the “Hiramatsu method”. Hiramatsu's method is described in “Japan Mining Association Vol. 81, No. 932, 1024 pages (1965)”. Specifically, the compression tester LOAD CELL AGS-500B TYPE: SBL-500K-350 manufactured by Shimadzu Corporation is used. The measurement is automatically performed at room temperature under the following conditions. In order to reduce the measurement error due to the difference of each particle, 10 points are measured for one type of sample, and the average value is adopted as the measured value.
Test load weight: 100kgf
Load speed: 2 mm / min.

  As a method for controlling the crushing strength of the catalyst molded body to a desired value, for example, in molding the active ingredient, the blending amount of the binder, the amount of water to be added, and the blending amount of the plasticizer are adjusted; Select and use; adjust extrusion pressure and temperature at the time of molding appropriately; adjust rotation speed and temperature at the time of stirring granulation; adjust spray speed, amount and temperature at the time of spray granulation as appropriate; Operation is mentioned.

<Size and shape of catalyst molded body>
The viewpoint that the size and shape of the molded catalyst used in the present invention can be appropriately changed depending on the type of reaction system and reactor used, and the original performance of the active component can be sufficiently exhibited without degrading the catalyst performance due to molding. Desirable from.
Specifically, it is preferable that the relationship between the height (L) of the catalyst layer of the reactor described later and the catalyst particle diameter (Dp) is greater than 50 in terms of L / Dp. Furthermore, it is preferable that the relationship between the inner diameter (Dr) of the reaction tube and Dp is greater than 10 in terms of Dr / Dp. Although the optimum value varies depending on the reaction conditions and the size of the reactor, L / Dp is particularly preferably 55 to 10,000, and Dr / Dp is particularly preferably 11 to 10,000.

  Here, the catalyst particle diameter (Dp) refers to the maximum diameter of the catalyst molded body. For example, when the molded body is elliptical, the catalyst particle diameter (Dp) refers to the long diameter.

<Method for producing catalyst molded body>
Although there is no restriction | limiting in particular as a manufacturing method of the catalyst molded object used by this invention, For example, it can manufacture by the method containing the following 3 processes.
(1) First step of preparing a reaction mixture by mixing at least an active ingredient such as zeolite and a binder (2) Extruding, stirring granulation or spray granulation of the reaction mixture obtained in the first step, Second step of obtaining a molded body precursor by pulverization and / or sieving as required (3) Third step of firing the molded body precursor obtained in the second step at a temperature in the range of 120 to 900 ° C.

(binder)
First, the binder used in the first step will be described.

  As the binder, any material can be used as long as the Na content in the catalyst molded body satisfies the above range. Silica sol, silicic acid solution obtained by exchanging Na in water glass with protons by ion exchange, silicones, alumina sol, boehmite And inorganic binders such as clay. Of these, silica-based ones having a low Na content are preferred. Among them, those having a low Na content in the binder are preferable, and silicones containing essentially no Na are preferable from that viewpoint. Silicones are preferable from the viewpoint that the compression strength of the molded product can be easily controlled.

  Here, the silicones refer to oligomers having a polysiloxane bond in the main chain, and include those in which a part of the substituents of the main chain of the polysiloxane bond is subjected to hydrolysis to become an OH group. Preferred silicones as the binder are compounds represented by the following general formula (I) having a polysiloxane bond or partial hydrolysates thereof.

（式（Ｉ）において、Ｒは、置換されていても良い、アルキル基、アリール基、アルケニル基、アルキニル基、アルコキシ基またはアリールオキシ基であり、Ｒ’は、置換されていても良いアルキル基、アリール基、アルケニル基またはアルキニル基であり、ｎは、１〜１００の数である。なお、複数あるＲは互いに同一であっても良く、異なるものであっても良い。また、複数あるＲ’は互いに同一であっても良く、異なるものであっても良い。）

(In formula (I), R is an optionally substituted alkyl group, aryl group, alkenyl group, alkynyl group, alkoxy group or aryloxy group, and R ′ is an optionally substituted alkyl group. , An aryl group, an alkenyl group or an alkynyl group, and n is a number from 1 to 100. Note that a plurality of R may be the same or different from each other. 'May be the same or different from each other.)

  R is preferably an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, Or a C6-C12 aryloxy group is mentioned, These may be substituted arbitrarily. More preferably, each independently includes an unsubstituted alkoxy group, an alkyl group, and an aryloxy group, particularly preferably an alkoxy group, and particularly preferably an ethoxy group or a methoxy group, and most preferably a methoxy group. .

  R ′ is preferably an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms, which are optionally substituted May be. Preferred is an unsubstituted alkyl group having 1 to 5 carbon atoms, more preferred is a methyl group or an ethyl group, and most preferred is a methyl group.

  The partial hydrolyzate of the compound represented by the above general formula (I) is a compound in which at least a part of R and R ′ is converted to an OH group by hydrolysis.

The repeating unit n is usually 1 to 100, preferably 2 to 50, more preferably 3 to 30.
Depending on the value of n, the compounds of the general formula (I) are present here in the form of monomers or in the form of long chains, optionally in the form of long branched oligomers.

  Examples of silicones used in the present invention include alkyl silicates conventionally called methyl silicate and ethyl silicate.

  These binders may be used alone or in combination of two or more.

  The method for producing a catalyst molded body according to the present invention will be described below by exemplifying a method for producing a catalyst molded body using zeolite as an active ingredient and a silica-based binder as a binder. The active ingredient used in the present invention and The binder is not limited to zeolite or silica binder.

(First step)
In the first step, at least a zeolite and a binder are mixed to prepare a reaction mixture.
The mixing ratio of zeolite and binder in the reaction mixture is usually 1 to 40 parts by weight, preferably 3 to 30 parts by weight in terms of SiO ₂ , assuming that the binder is silica-based with respect to 100 parts by weight of zeolite. Parts, more preferably 5 to 20 parts by weight. If the amount of the binder is too small from this range, the compression strength of the resulting molded product tends to decrease too much, and if it is too large, the compression strength of the resulting molded product is too high, which has an adverse effect on poor reaction results and catalyst life. Tend to affect.

  Usually, water is added to the reaction mixture. The blending ratio is usually 10 to 500 parts by weight with respect to 100 parts by weight of zeolite, although it depends on the molding method. More specifically, in the case of extrusion molding or stirring granulation, water is 10 to 100 parts by weight, preferably 10 to 60 parts by weight with respect to 100 parts by weight of zeolite, and 30 to 400 parts by weight in the case of spray drying. Parts, preferably 40-220 parts by weight.

In addition, to the reaction mixture, celluloses such as methylcellulose, and organic additive materials such as starch and polyvinyl alcohol may be added for the purpose of enhancing fluidity, depending on the characteristics during kneading and extrusion. .
The blending ratio of these additives is usually 0.1 to 5 parts by weight, preferably 0.5 to 2 parts by weight with respect to 100 parts by weight of zeolite. If the amount added is too large, the strength of the resulting molded product tends to decrease.

  Moreover, you may add an alkaline-earth metal compound to a molded object in order to raise the intensity | strength of a molded object or to improve selectivity. As the kind of alkaline earth metal element, Ca, Mg or Sr is preferable, and specific examples of the compound include forms of these carbonates, phosphates or oxides.

(Second step)
In the second step, the reaction mixture obtained in the first step is subjected to extrusion molding, stirring granulation or spray granulation, and if necessary, pulverized and / or sieved to obtain a molded body precursor.

  As an apparatus used for extrusion molding, stirring granulation, or spray granulation, a known extrusion molding machine, stirring granulator, or spray dryer can be used.

  In the case of stirring granulation, usually, zeolite, a binder and a plasticizer are mixed at room temperature, and then a predetermined amount of water is added to perform granulation (stirring). The granulation time is not particularly limited, but is usually 1 to 120 minutes, preferably 2 to 30 minutes. If the granulation time is too short, the granulation is insufficient and the particle size distribution of the granulated product becomes wide. If the granulation time is too long, the moisture in the system volatilizes during granulation, making moisture management difficult. After granulation, a molded body precursor is obtained by drying at 50 to 150 ° C. as necessary.

In the case of extrusion molding, usually, zeolite, a binder, a plasticizer and water are added and kneaded, and then molded by an extruder. Although there is no restriction | limiting in particular in the pressure in the case of shaping | molding, Usually, it is about 5-500 kgf / cm < ² >. After the extrusion, if necessary, drying at a temperature of about 50 to 150 ° C., pulverization and classification are performed to obtain a desired molded body precursor.

  In the case of spray drying, a slurry obtained by adding zeolite, a binder, a plasticizer, and water and mixing them is introduced into a spray dryer. As conditions, the solid concentration of the slurry of the reaction mixture is usually about 20 to 70% by weight, the spray dryer inlet temperature is preferably about 150 to 450 ° C, and the outlet temperature is preferably about 60 to 225 ° C. The particle size of the compact precursor depends on the size of the sprayed droplets, and also depends on the slurry supply rate, the slurry concentration, and the spray type. Note that the strength of the granulated product tends to be increased and the bulk density tends to be increased by lowering the spray drying temperature, but if it is too low, the proportion of particles reaching the wall surface before drying increases, and the particle density is reduced. Since the rate decreases, it is preferable to set a relatively high value within the above range.

  The above-mentioned conditions may be selected so that the zeolite in the molded body contains the template (template) used for its synthesis up to the second step, or the template is removed by calcination or the like. You can go.

(Third step)
In a 3rd process, the molded object precursor obtained at the 2nd process is baked at the temperature within the range of 120-900 degreeC. The temperature is preferably 200 ° C. or higher, more preferably 250 ° C. or higher, and particularly preferably 300 ° C. or higher. On the other hand, it is preferably 800 ° C. or lower, more preferably 700 ° C. or lower. By calcination in the above temperature range, the binder is substantially cross-linked, high compression strength is obtained, and the molded article produced has good catalytic properties. When the calcination temperature is too high, the structure of the zeolite is destroyed and the catalyst performance tends to be lowered. If the calcination temperature is too low, when the zeolite is contained up to the second step while containing the template, the template is not sufficiently removed and the catalyst performance tends to be lowered, and the crosslinking of the binder does not proceed sufficiently, and the compressive strength There is also a tendency to become insufficient. This third step is essential when the zeolite is contained up to the second step while containing the template, but this third step can be omitted in some cases when the template is not contained.

  In the firing step, known firing methods such as a fixed bed, a fluidized bed, and a rotary furnace can be applied. The firing gas is preferably circulated in order to quickly remove volatile substances and moisture generated by firing. As the firing gas, an oxygen-containing gas such as air or an inert gas such as nitrogen can be used, but a diluted oxygen-containing gas obtained by diluting air with an inert gas such as nitrogen is preferably used.

[Reaction raw materials]
Next, the olefin having 2 or more carbon atoms, methanol, and dimethyl ether used as reaction raw materials in the present invention will be described.

<Olefin>
The olefin having 2 or more carbon atoms used as a raw material for the reaction is not particularly limited. For example, FT (Fischer) using as raw material hydrogen / CO mixed gas obtained by gasification of coal (C4 raffinate-1, C4 raffinate-2, etc.) produced from petroleum feedstock by catalytic cracking or steam cracking Tropsch) obtained by synthesis, obtained by oligomerization reaction including ethylene dimerization reaction, obtained by dehydrogenation or oxidative dehydrogenation of paraffins having 2 or more carbon atoms, obtained by MTO reaction 2 or more, particularly 2 to 10 carbon atoms, obtained by various known methods such as those obtained by dehydration reaction of alcohol, those obtained by hydrogenation reaction of a diene compound having 4 or more carbon atoms, etc. Olefin can be used arbitrarily. At this time, olefins having 2 or more carbon atoms resulting from each production method are used. It may be used as it states that the compounds of mixed arbitrarily to be used was purified olefins.

<Methanol, dimethyl ether>
The origin of production of methanol and / or dimethyl ether used as a raw material for the reaction is not particularly limited. For example, one obtained by hydrogenation reaction of coal and natural gas, and by-product hydrogen / CO mixed gas in the steel industry, one obtained by reforming reaction of plant-derived alcohols, one obtained by fermentation method And those obtained from organic materials such as recycled plastic and municipal waste. At this time, a state in which compounds other than methanol and dimethyl ether resulting from each production method are arbitrarily mixed may be used as it is, or a purified one may be used.

[Reaction operations and conditions]
Hereinafter, the operation and conditions of the propylene production reaction of the present invention using the above-described catalyst and reaction raw materials will be described.

<Reactor>
In the present invention, the reaction of an olefin having 2 or more carbon atoms with methanol and / or dimethyl ether is a gas phase reaction. Although there is no restriction | limiting in particular in the form of this gas phase reactor, Usually, a continuous type fixed bed reactor and a fluidized bed reactor are selected.

  In addition, when packing the above-mentioned catalyst into the fluidized bed reactor, in order to keep the temperature distribution of the catalyst layer small, particulates inert to the reaction such as quartz sand, alumina, silica, silica-alumina, etc. are mixed with the catalyst. And may be filled. In this case, there is no particular limitation on the amount of granular material inactive to the reaction such as quartz sand. In addition, it is preferable that this granular material is a particle size comparable as a catalyst from the surface of uniform mixing property with a catalyst.

  Further, the reaction substrate (reaction raw material) may be divided and supplied to the reactor for the purpose of dispersing heat generated by the reaction.

The catalyst used in the present invention has less coking than the conventional catalyst and the rate of catalyst deterioration is slow, but when performing continuous operation for one year or longer, it is necessary to regenerate the catalyst during operation.
For example, when selecting a fixed bed reactor, it is desirable to install at least two reactors and operate while switching between reaction and regeneration. As the form of the fixed bed reactor, a multitubular reactor or an adiabatic reactor is selected.
On the other hand, when selecting a fluidized bed reactor, it is preferable to carry out the reaction while continuously feeding the catalyst to the regeneration tank and continuously returning the catalyst regenerated in the regeneration tank to the reactor.

  Here, examples of the regeneration operation of the catalyst include those that regenerate the catalyst introduced from the reactor by treating it with nitrogen gas containing oxygen or water vapor.

<Feed concentration ratio of olefin and methanol and / or dimethyl ether>
The amount of olefin having 2 or more carbon atoms fed to the reactor is usually 0.1 or more, preferably in a molar ratio with respect to the total number of moles of methanol fed to the reactor and twice the number of moles of dimethyl ether. It is 0.2 or more, usually 10 or less, preferably 5 or less.
That is, when the supply molar amount of the olefin having 2 or more carbon atoms is M _c2 , the supply molar amount of methanol is M _m , and the supply molar amount of dimethyl ether is M _dm , M _c2 is 0.1 of (M _m + 2M _dm ). It is preferably 10 to 10 times, particularly preferably 0.2 to 5 times.
If the supply concentration ratio is too low or too high, the reaction is slow, which is not preferable.

That is, the present invention is also characterized in that the reaction rate is remarkably increased by supplying an olefin having 2 or more carbon atoms and methanol and / or dimethyl ether in an appropriate concentration ratio.
When the olefin having 2 or more carbon atoms and methanol and / or dimethyl ether are supplied to the reactor, they may be supplied separately or may be supplied after mixing a part or all of them in advance.

<Substrate concentration>
There is no particular limitation on the total concentration (substrate concentration) of olefins having 2 or more carbon atoms, methanol and dimethyl ether in all the feed components fed to the reactor, but the sum of olefins having 2 or more carbon atoms, methanol and dimethyl ether is 90 mol% or less is preferable in all supply components. More preferably, it is 20 mol% or more and 70 mol% or less. If the substrate concentration is too high, aromatic compounds and paraffins are prominently produced and the propylene selectivity tends to decrease. On the contrary, if the substrate concentration is too low, the reaction rate becomes slow, so a large amount of catalyst is required, and the reactor tends to be too large.
Therefore, it is preferable to dilute the reaction substrate with a diluent described below as necessary so as to obtain such a substrate concentration.

<Diluent>
In the reactor, in addition to olefins having 2 or more carbon atoms and methanol and / or dimethyl ether, helium, argon, nitrogen, carbon monoxide, carbon dioxide, hydrogen, water, paraffins, methane and other hydrocarbons, aromatics Gases that are inert to the reaction, such as group compounds and mixtures thereof, can be present, and among these, water (water vapor) is preferably present together.
As such a diluent, impurities contained in the reaction raw material may be used as they are, or a separately prepared diluent may be mixed with the reaction raw material and used.
The diluent may be mixed with the reaction raw material before entering the reactor, or may be supplied to the reactor separately from the reaction raw material.

<Space velocity>
The space velocity mentioned here is the flow rate of olefin having 2 or more carbon atoms and methanol and / or dimethyl ether, which are reaction raw materials per weight of the catalyst (catalytic active component), and the weight of the catalyst is the granulation of the catalyst. -It is the weight of the inactive component used for molding and the catalytically active component not containing a binder. The flow rate is the total flow rate (weight / hour) of an olefin having 2 or more carbon atoms and methanol and / or dimethyl ether.

Space velocity varies depending substrates, preferably between 0.1 hr ^-1 of 500HR ^-1, more preferably 300HR ^-1 from 0.2 hr ^-1, still it is between 1.0 hr ^-1 for 200 hours ^-1 preferable. If the space velocity is too high, the conversion of the raw material olefin and methanol and / or dimethyl ether is low, and sufficient propylene selectivity cannot be obtained. On the other hand, if the space velocity is too low, the amount of catalyst necessary to obtain a certain production amount increases, the reactor becomes too large, and undesirable by-products such as aromatic compounds and paraffin are produced, and propylene selection is performed. This is not preferable because the rate decreases.

<Reaction temperature>
The lower limit of the reaction temperature is usually about 300 ° C. or higher, preferably 400 ° C. or higher, more preferably 450 ° C. or higher. The upper limit of the reaction temperature is usually 700 ° C. or lower, preferably 600 ° C. or lower. If the reaction temperature is too low, the reaction rate tends to be low, a large amount of unreacted raw material tends to remain, and the yield of propylene also decreases. On the other hand, if the reaction temperature is too high, the yield of propylene is significantly reduced.

<Reaction pressure>
The upper limit of the reaction pressure is usually 2 MPa (absolute pressure, the same applies hereinafter), preferably 1 MPa or less, and more preferably 0.7 MPa or less. The lower limit of the reaction pressure is not particularly limited, but is usually 1 kPa or more, preferably 50 kPa or more. If the reaction pressure is too high, the amount of undesired by-products such as paraffins and aromatic compounds increases, and the yield of propylene tends to decrease. If the reaction pressure is too low, the reaction rate tends to be slow.

<Reaction product>
As the reactor outlet gas (reactor effluent), a mixed gas containing reaction product propylene, unreacted raw materials, by-products and a diluent is obtained. The propylene concentration in the mixed gas is usually 5 to 95% by weight.
The unreacted raw material is usually an olefin having 2 or more carbon atoms. Depending on the reaction conditions, methanol and / or dimethyl ether are included, but it is preferable to carry out the reaction under such reaction conditions that the conversion of methanol and / or dimethyl ether is 100%. Thereby, separation of the reaction product and the unreacted raw material becomes easy.
By-products include ethylene, olefins having 2 or more carbon atoms, paraffins, aromatic compounds and water.

<Product separation>
The mixed gas containing propylene, unreacted raw materials, by-products and diluent as reaction product outlet gas is introduced into a known separation / purification facility, and is collected and purified according to each component. What is necessary is just to process recycling and discharge.
Part or all of the components other than propylene (olefin, paraffin, etc.) are preferably recycled after being separated and purified and mixed with the reaction raw materials or directly supplied to the reactor. In addition, among the by-products, components inactive to the reaction can be reused as a diluent.

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

[Manufacture of catalyst]
The catalysts used in the following examples and comparative examples were prepared as follows.
<Preparation of catalytically active component>
(Preparation Example 1)
Tetra-n-propylammonium bromide (TPABr) 53.2 g and sodium hydroxide 9.6 g are dissolved sequentially in 560 g of water, and then colloidal silica (SiO ₂ = 40 wt%, Al <0.1 wt%). A mixed solution of 150 g and 70 g of water was slowly added, and stirred sufficiently to obtain an aqueous gel. Next, this gel was charged into a 1000 ml autoclave, and hydrothermal synthesis was performed at 170 ° C. for 72 hours while stirring at 300 rpm under a self-pressure. The product was subjected to pressure filtration to separate solid components, sufficiently washed with water, and then dried at 100 ° C. for 24 hours. The dried catalyst was calcined at 550 ° C. for 6 hours under air flow to obtain Na-type aluminosilicate.

  60 g of this Na-type aluminosilicate was suspended in 1000 cc of 1M ammonium nitrate aqueous solution and stirred at 100 ° C. for 2 hours. The liquid after the treatment was separated into solid components by suction filtration, sufficiently washed with water, then suspended again in 100 cc of 1M aqueous ammonium nitrate solution and stirred at 100 ° C. for 2 hours. After the treatment, the solid component was separated by suction filtration, sufficiently washed with water, and then dried at 100 ° C. for 24 hours. The dried catalyst was calcined at 500 ° C. for 4 hours under air flow and removed by exchanging Na with protons to obtain an H-type aluminosilicate (referred to as zeolite 1).

This zeolite 1 was confirmed by XRD (X-ray diffraction) to have a zeolite structure of MFI type.
As a result of elemental analysis of the composition of the zeolite 1, it was SiO ₂ / Al ₂ O ₃ = 1100 (molar ratio) (Si / Al = 550).

(Preparation Example 2)
57.2 g of tetra-n-propylammonium bromide (TPABr), 24.8 g of boric acid, 1.24 g of aluminum nitrate nonahydrate and 10.2 g of sodium hydroxide are sequentially dissolved in 560 g of water, and then colloidal. A mixed solution of 150 g of silica (SiO ₂ = 40% by weight, Al <0.1% by weight) and 70 g of water was slowly added and sufficiently stirred to obtain an aqueous gel. Next, this gel was charged into a 1000 ml autoclave, and hydrothermal synthesis was performed at 170 ° C. for 72 hours while stirring at 300 rpm under a self-pressure. Subsequent treatment was performed in the same manner as in Preparation Example 1 to obtain an H-type boroaluminosilicate (referred to as zeolite 2).

This zeolite 2 was confirmed by XRD that the structure of the zeolite was MFI type.
When the composition of the zeolite 2 was quantified by elemental analysis, it was SiO ₂ / Al ₂ O ₃ = 200 (molar ratio) and SiO ₂ / B ₂ O ₃ = 118 (molar ratio). The ratio to Si was Si / (Al + B) = 37.

<Molding of catalytically active component>
(Molding example 1)
1 part by weight of methylcellulose as a molding aid is added to 100 parts by weight of zeolite 1 obtained in Preparation Example 1 and kneaded well. Further, methyl silicate (manufactured by Mitsubishi Chemical Corporation, MKS silicate (registered trademark) MS56S) is added as a binder. In the general formula (I), R ′ = CH ₃ , R = OCH ₃ and the SiO ₂ content is 59 wt% in terms of SiO ₂ content) and 20 parts by weight were added and kneaded well. Thereafter, 40 parts by weight of water was sprayed with a sprayer while continuing kneading to obtain a clay-like sample. Next, this clay-like sample was extrusion molded at a pressure of 50 kg / cm ² using an extruder. The extruded granule precursor was calcined at 550 ° C. for 8 hours in an air atmosphere to obtain a molded body of H-type aluminosilicate (referred to as catalyst A). The Na content of this catalyst A was 0.01% by weight or less, which was below the detection limit. Further, the compression strength was measured and found to be 3.4 MPa. In addition, the shape was a granule and the particle diameter (Dp) was 0.5 mm.

(Molding example 2)
In Molding Example 1, 20 parts by weight of Snowtex 50 (SiO ₂ content 50% by weight), which is a silica sol manufactured by Nissan Chemical Industries, Ltd., was added to methyl silicate and the amount of water to be sprayed was changed. A compact was obtained from zeolite 1 (referred to as catalyst B) by the same operation as in molding example 1 except that the amount was 30 parts by weight. The total amount of water used for molding is the same as in molding example 1 because there is water in the silica sol.
The Na content of this catalyst B was 0.07% by weight. Moreover, it was 1.0 Mpa when the compressive strength was measured.

(Molding example 3)
In Molding Example 1, changing the binder to methyl silicate, adding 50 parts by weight of F-120 (SiO ₂ content 20% by weight), which is a silica sol made by Catalyst Kasei Co., Ltd., and not using water to be sprayed Except for the above, a molded body was obtained from zeolite 1 by the same operation as in molding example 1 (referred to as catalyst C).
The Na content of this catalyst C was 0.01% by weight or less, which was below the detection limit. Moreover, it was 0.7 MPa when the compressive strength was measured.

(Molding example 4)
Using the zeolite 2 obtained in Preparation Example 2 as a zeolite and using 10 parts by weight of methyl silicate as a binder, a molded body was obtained from the zeolite 2 by the same operation as the molding example 1 (referred to as catalyst D).
The Na content of the catalyst D was 0.01% by weight or less below the detection limit. Further, the compression strength was measured and found to be 4.3 MPa.

(Molding example 5)
A compact was obtained from zeolite 2 (referred to as catalyst E) by the same operation as in molding example 1 except that zeolite 2 obtained in Preparation Example 2 was used as the zeolite.
The Na content of this catalyst E was 0.01% by weight or less, which was below the detection limit. Further, the compression strength was measured and found to be 23.6 MPa.

[Propylene production]
The production examples and comparative examples of propylene using the catalysts A to E are shown below.

<Relationship between Na content and reaction results>
Example 1
Propylene was produced from catalyst A using ethylene and methanol as raw materials.
A normal pressure fixed bed flow reactor was used for the reaction, and a mixture of 25 mg of the catalyst A and 0.5 of quartz sand was packed in a quartz reaction tube having an inner diameter (Dr) of 6 mm. The catalyst layer height (L) was 30 mm. The reactor was fed with ethylene, methanol, water (26 wt%) and nitrogen through an evaporator. The raw material composition is ethylene / methanol = 1 (molar ratio), methanol = 6.5 mol%, the reaction material space velocity (Space Velocity: SV) is 0.23 Hr ⁻¹ , the reaction temperature is 550 ° C., and the reaction pressure is normal. Pressure.
The product 40 minutes after the start of the reaction was analyzed by gas chromatography. Table 1 shows the analysis results. The conversion rate of methanol reached 100%, and the selectivity for propylene (mol% in terms of carbon) was 63.8%.

(Reference Example 1)
Production of propylene in the same manner as in Example 1 except that instead of the catalyst A, zeolite 1 (the one before molding; obtained in Preparation Example 1), which is an active component of the catalyst A, was used. Table 1 shows the analysis results of the product 40 minutes after the start of the reaction.
The conversion of methanol reached 100% and the selectivity for propylene was 62.6%.
From this result, it can be seen that the reaction results are almost the same in Example 1 and Reference Example 1, and that the molded product of catalyst A sufficiently expresses the original catalytic performance of zeolite 1 as the active ingredient.

(Comparative Example 1)
Propylene was produced under the same reaction conditions as in Example 1 using Catalyst B instead of Catalyst A, and the analysis results of the product 40 minutes after the start of the reaction are shown in Table 1.
In the catalyst B, the conversion rate of methanol did not reach 100%, the activity was low as compared with Example 1, and the selectivity for propylene was also a low value of 48.4%.
Thus, even if the same zeolite raw material is used, it can be seen that if the Na content of the molded body is large, the reaction results deteriorate and the original catalytic performance of the active ingredient zeolite is not expressed.

<Relationship between compressive strength and catalyst life>
Next, a synthesis reaction of propylene using butene and methanol as raw materials was performed for a long time using a catalyst molded body having a low Na content. The product was analyzed by gas chromatography every 6 hours, and the reaction was continued until unreacted methanol was detected in the product. And the total amount of propylene produced | generated per 1 kg of catalyst molded bodies was computed using all the analysis results until one time (6 hours ago) before the analysis by which methanol was detected in the product. The larger the value, the longer the life of the catalyst. Thus, the effect of compressive strength on catalyst life was investigated.
The results of the following examples are shown in Table 2.

(Example 2)
Propylene (PPY) was produced from catalyst C using butene and methanol as raw materials.
A normal pressure fixed bed flow reactor was used for the reaction, and a quartz reaction tube having an inner diameter (Dr) of 6 mm was filled with a mixture of 100 mg of the catalyst A and 0.5 of quartz sand. The catalyst layer height (L) was 40 mm. The reactor was fed with 1-butene, methanol and nitrogen through an evaporator. The raw material composition was 1-butene / methanol = 2 (molar ratio), methanol = 10 mol%, and the space velocity (Space Velocity: SV) of the reaction raw material was 2.8 Hr ⁻¹ . The reaction temperature was 550 ° C. and the reaction pressure was normal pressure.
After starting the reaction, the product was analyzed by gas chromatography every 6 hours. The reaction was completed within 198 hours, but it was found that all the methanol was consumed even after 198 hours, and the activity of the catalyst did not decrease after 198 hours. The total amount of propylene in this reaction is calculated per 1 kg of the catalyst by accumulating the amount of propylene every 6 hours as the average value of the 6 hours that the analysis was performed with the amount of propylene obtained from the analysis value every 6 hours. 197.9 kg-PPY / kg-catalyst.
In this reaction, the entire amount of methanol is consumed after 195 hours, and the function as a catalyst is maintained after 195 hours, so that the total amount of propylene obtained from the catalyst A is 197.9 kg-PPY / kg-catalyst or more.

(Example 3)
Propylene was produced using the catalyst A instead of the catalyst C under the same reaction conditions as in Example 2. In the same manner as in Example 2, analysis was performed by gas chromatography every 6 hours after the start of the reaction, and the reaction was continued until the time when unreacted methanol was detected in the product.
In Catalyst A, 316.7 kg-PPY / kg-catalyst of propylene was produced from the start of the reaction until 6 hours before the time when methanol was detected in the product.

Example 4
Propylene was produced in the same manner as in Example 2, except that catalyst D was used instead of catalyst C, and the space velocity (Space Velocity: SV) of the reaction raw material was set to 5.6 Hr- ¹ .
For catalyst D, 160.2 kg-PPY / kg-catalyst of propylene was produced from the start of the reaction until 6 hours before the time when methanol was detected in the product.

(Example 5)
Propylene was produced under the same reaction conditions as in Example 4 using Catalyst E instead of Catalyst D.
Catalyst E produced 138.7 kg-PPY / kg-catalyst of propylene from the start of the reaction until 6 hours before the time when methanol was detected in the product.

  In Examples 2 to 4, the amount of propylene produced per 1 kg of the catalyst was 160 kg-PPY / kg-catalyst or more, whereas the catalyst E having a high compressive strength was less than 140 kg-PPY / kg-catalyst. From this, it can be seen that if the compressive strength is too high, the catalyst life is reduced.

Claims (2)

In a method for producing propylene by contacting a raw material mixture containing an olefin having 2 or more carbon atoms and methanol and / or dimethyl ether in the presence of a catalyst, the molded article contains an aluminosilicate having a cation as a proton as an active ingredient. Then, a method for producing propylene, wherein a molded product having a Na content of 0.06% by weight or less based on the total weight of the molded product is used as the catalyst.   The method for producing propylene according to claim 1, wherein the compact has a compressive strength of 0.2 to 20 MPa.