KR20140067564A - Process for production of olefins - Google Patents

Abstract

The present invention relates to a method for producing olefin. The method for producing olefin according to one embodiment of the present invention includes: a step of separating C5 mixture oil into a first stream and a second stream; a step of generating a third stream containing dicyclopentadiene; a step of separating the third stream into a fourth stream and a fifth stream; a step of collecting a stream and a residual stream; a step of collecting isoprene from the fifth stream; and a step of converting the first stream into a stream including ethylene and propylene.

Description

PROCESS FOR PRODUCTION OF OLEFINS [0002]

The present invention relates to a process for producing olefins, and more particularly, to a process for producing olefins having 2 to 5 carbon atoms from C5 mixed olefins produced after a naphtha cracking process.

Light olefins such as ethylene and propylene are the core raw materials of petrochemical products and their demand is increasing worldwide, and they are of great importance in industry. Generally, light olefins are cracked from various raw materials such as natural gas, LPG, naphtha, gas oil, crude oil, ethyl alcohol, etc., It is known that it can be produced through processes such as dehydrogenation and the like. However, up to now, light olefins for industrial use are mostly produced by naphtha cracking, ie, naphtha cracking reaction.

Naphtha cracking is one of the most important processes in the petrochemical industry as a reaction to produce ethylene, propylene, butylene, and BTX by pyrolysis of naphtha obtained from a crude oil atmospheric distillation apparatus at a high temperature of 800 ° C or higher. Naphtha cracking mainly produces light olefins, ethylene and propylene, and it is known that various byproducts such as C4 fraction, C5 fraction, and BTX are produced together. Among them, C4 oil is used as a base oil for adhesives and synthetic rubbers, and C6 or higher benzene, toluene and xylene are used as core raw materials of synthetic fibers, The demand and the application site are not clear, so they are recycled to the naphtha cracking center or used for applications having low added value such as gasoline additives. Hereinafter, the prior art disclosing a method for obtaining a useful raw material from a hydrocarbon mixture such as naphtha cracking oil or the like known so far will be described.

U.S. Patent No. 6,395,953 proposes a method for purifying butadiene and isoprene in high purity by inhibiting the polymerization of diene compounds using a mixture of water and an amide in C4 or C5 hydrocarbons as a solvent. However, in the utilization of oils other than isoprene or butadiene .

U.S. Patent No. 4,009,084 proposes a method of extracting and distilling isoprene and butadiene from C5 oil using N-formyl morpholine, but there is a problem of using an excessive amount of an extractant, No other oil treatment is mentioned.

U.S. Patent No. 5,898,091 discloses a process for the conversion of an isoolefin to an internal olefin via selective hydrogenation in a mixture of C4 and C5 hydrocarbons and then an isoolefin is reacted with an alcohol to synthesize an ether, However, additional raw materials such as ethylene are consumed and it is required to examine the economic feasibility of the synthesized ether.

Patent Publication No. 0217979 discloses a method for separating and recovering cyclopentadiene in high purity from a effluent in which dimeric cyclopentadiene contained in naphtha cracked oil is thermally quantized and then dimerized through two-stage distillation to concentrate dicyclopentadiene , And Patent Publication No. 0494022 discloses a method of separating dicycloheptadienes from C5 oil produced by hydrocarbon pyrolysis, separating dicyclopentadiene by fractional distillation, monomersizing dicyclopentadiene in the presence of a high boiling solvent and a polymerization inhibitor, Purity cyclopentadiene by fractional distillation, dimerization through heating, formation of a dicyclopentadiene rich effluent and separation of high purity dicyclopentadiene by rectification, and the like. Patent Publication No. 0947893 discloses that a specific hydrocarbonization having a boiling point similar to the boiling point of dicyclopentadiene There has been proposed a method of purifying crude dicyclopentadiene obtained from naphtha cracker byproducts at a high purity by selecting water as an auxiliary fluid. However, in these patents, only the separation of dicyclopentadiene among useful components of naphtha cracking oil It focuses but does not mention other useful ingredients either.

On the other hand, a catalytic decomposition technique using a catalyst has been attracting attention as a method for reducing energy consumption due to high temperature pyrolysis in the production of light olefins. Catalytic catalytic cracking is performed at a reaction temperature as low as about 50 to 200 ° C compared to the conventional pyrolysis process, so energy consumption is low and the generation of coke on the inner wall of the tube is suppressed, thereby extending the cycle and lifetime of the plant. In addition, it is expected that the supply and demand imbalance of ethylene and propylene can be solved because it is possible to minimize the environmental pollution by reducing the generation of carbon dioxide and to control the composition of the produced olefin according to demand.

A typical catalyst system used for producing light olefins through catalytic catalytic cracking is a catalytic cracking process using an acid catalyst. Among various acid catalysts, zeolite is most widely used because zeolite is easy to control acidity through chemical composition change and has shape selectivity so that conversion of reactant and yield of light olefin can be easily controlled This is because. ZSM-5, USY, REY, β-zeolite and the like are used as typical zeolites for catalytic catalytic cracking.

The ZSM-5 catalyst is a zeolite A having an 8-membered ring pore size and erionite and a 12-membered ring, Unlike the faujasite with super-cage, the mordenite with zeolite X and Y or the two-dimensional pore structure, the pore size of the medium-sized 10-membered ring And has a uniform pore size and structure due to a pore structure formed by a three-dimensional intersection of a straight channel of 5.4 × 5.6 Å and a sinusoidal channel of 5.1 × 5.5 Å, (H. Krannila et al., J. Catal., Vol.135, p115, 1992), which is excellent in selectivity, low in inertness, and excellent in thermal stability due to high Si / Al ratio.

As described above, the ZSM-5 catalyst is used in various reactions including catalytic catalytic decomposition reaction, isomerization reaction and esterification reaction due to its unique structure and excellent acid characteristics. However, when the reaction proceeds under high temperature and high humidity conditions, There is a problem in that the structure is collapsed and the acid sites are reduced and the activity of the catalyst is reduced. Therefore, attempts have been made to introduce various materials to improve the instability of the catalyst, which occurs under high temperature and high humidity reaction conditions. A method for improving the thermal stability of representative catalysts is to add manganese and phosphorus to the zeolite (T. Blasco et al., J. Catal., Vol. 237, p. 267, 2006). When the zeolite such as ZSM-5 is modified with phosphate ion, the Si-OH-Al moiety serving as the Bronsted acid point in the zeolite is modified by the phosphate ion (PO4 ^{3 -} ) to stabilize the unstable P = O group Thereby minimizing dealumination. However, the method of simply modifying phosphorus in zeolite can contribute to suppressing catalyst deactivation for a long time by improving the hydrothermal stability of the catalyst, but it is inadequate to improve the production of light olefins.

In addition to the efforts to improve the thermal stability of the catalyst, the important thing is to control the product distribution after reaction. In order to maximize the production of light olefins, the production of paraffins and aromatic compounds should be suppressed and the production of olefins should be maximized. This requires an improvement in the reaction process, such as lowering the reaction pressure, raising the reaction temperature, lowering the residence time of the reactants, and appropriately controlling the ratio of the reactants to the catalyst (MA Den Hollander et al., Appl. Catal. A, vol.223, p85, 2002), along with efforts to improve the production of light olefins through the development of new catalysts. As a part of this effort, a method of preparing a catalyst by adding a transition metal or a rare earth metal to a ZSM-5 catalyst has been carried out (N. Rahimi et al., Appl. Catal. A, vol.398, p1, 2011). In this document, it is reported that when a transition metal such as iron or chromium is added to ZSM-5, the reactant hydrocarbon is dehydrogenated to induce a decomposition reaction more easily, thereby producing more light olefins. It has been reported that the addition of rare earth metals such as neodymium, cerium, and lanthanum to ZSM-5 improves the selectivity of light olefins. However, the effect of rare earth metals on the selectivity of light olefins Opinion is divided. When a metal such as a transition metal or a rare earth metal is used, large metal atoms are located at the pore openings of the zeolite, which may cause a problem of lowering the reaction activity when the pores are closed. Therefore, it can be said that there is a limitation in modifying metals to pure ZSM-5 having microporous characteristics, and ZSM-5 having fine and mesoporous porosity characteristics is required to overcome this.

U.S. Patent No. 6,835,863 discloses a process for the catalytic cracking of naphtha using a shaped catalyst comprising 5 to 75% by weight of ZSM-5 and ZSM-11, 25 to 95% by weight of silica or kaolin, and 0.5 to 10% by weight of phosphorus. However, there is no mention of hydrothermal stability of specific starting materials of phosphorus and shaped catalysts, and no catalyst having mesoporous characteristics is used.

US Patent Publication No. 20060011513 discloses a technique for selecting one of lanthanide, Sc, Y, La, Fe and Ca to zeolites such as ZSM-5, β, mordenite and ferrierite, There is no mention of the specific chemical structure of the phosphate and its description of its role is lacking, and no technology for improving the olefin yield is specified.

U.S. Patent No. 7,531,706 discloses a method for producing light olefins using a pentasil-type zeolite modified with a rare-earth metal, manganese or zirconium with phosphorus, wherein the modified metal has a hydrothermal stability of the catalyst and a yield of light olefin However, it is not enough to interpret the specific role of the metals, and it is only aimed at improving the durability of the zeolite.

Non-Patent Document 1 (G. Zhao et al., J. Catal. Vol. 48, p29, 2007) was intended to improve hydrothermal stability by introducing phosphorus into HZSM-5. As a result, the introduction of phosphorus contributed to improvement of hydrothermal stability. However, the introduction of phosphorus resulted in a drastic decrease in surface area and pore volume due to blocking of the inlet of micropores, and the limitation that phosphorus does not play a role in improving light olefin production have.

Non-Patent Document 2 (J. Lu et al., Catal. Commun., Vol. 7, p199, 2006) studied the preparation of light olefins by catalytic catalytic cracking of isobutane. As a result of preparing a catalyst modified with iron on the basis of ZSM-5 catalyst, it has been reported that the modification of iron makes it possible to produce more light olefins by improving the acid property of the catalyst. However, , The activity was decreased rapidly. This can be attributed to the microporosity of ZSM-5, which is caused by aggregation between iron atoms. Further, the hydrothermal stability of the catalyst is not mentioned.

In a non-patent document 3 (W. Xiaoning et al., J. Rare Earths, vol.25, p321, 2007), while conducting a study to produce light olefins from butane using a ZSM-5 catalyst containing a rare earth metal, The effect of the acid on the acid property of the catalyst is discussed and the effect of the acid property change of the catalyst on the reaction activity is discussed. However, the effect of the rare earth metal on the base property is not considered, The effect of the properties on the mechanism of the degradation reaction is not mentioned.

On the other hand, isoprene was first produced by CE Williams in 1860 by pyrolysis of natural rubber. In 1955, it began to be used as a raw material for synthetic rubber, and mass production began. In the past, Kurary and Sumitomo Co., A technique of separating isobutylene from an C5 oil obtained mainly from a naphtha cracker, as described above, is mainly produced by a synthesis method such as a reaction by reacting isobutylene under an acid catalyst, or a dehydrogenation reaction of isopentane by Houndry or ABB Lummus .

It is difficult to separate isoprene in high purity by conventional distillation because C5 oil contains many components having similar boiling points. Therefore, methods such as multi-stage distillation, extractive distillation, liquid-liquid extraction, heat treatment and the like have been attempted. In commercialized processes, extractive distillation using a specific extractant is mainly adopted, Techniques for solving various problems are presented. For example, U.S. Patent No. 3,947,506 discloses a method for recovering isoprene through two successive distillations in a C5 stream comprising isoprene, n-pentane, and other C5 hydrocarbons, and Patent No. 0542782 discloses a process for recovering isoprene Discloses a method for efficiently producing a purified conjugated diene by inhibiting the production of a popcorn polymer or a rubber-like polymer in the step of separating the conjugated diene by extractive distillation using an amide compound as an extraction solvent from a petroleum oil containing it Publication No. 2003-0026427 discloses a technique for minimizing energy consumption of an entire process by suggesting operating conditions of a distillation column and the like in a process of separating isoprene from C5 fraction by extractive distillation. Patent No. 0783342 Separation and purification of conjugated dienes that can effectively and stably suppress the formation of rubber substances in the distillation column Patent Document No. 0845750 discloses a technique for separating and purifying conjugated dienes such as isoprene and butadiene of high purity from petroleum fractions by using a method of refining Discloses a method and an apparatus for separating and purifying a conjugated diene that can effectively suppress the generation of popcorn polymer in the apparatus.

However, the isoprene separation techniques by extractive distillation use a purification tower and an extraction tower, and particularly, it is necessary to use a purification tower having a theoretical plate number of 300 or more in order to produce isoprene of high purity, which is very disadvantageous in terms of energy consumption, Global warming due to greenhouse gases such as carbon dioxide resulting from fuel use, and environmental problems.

Here, reactive extraction, that is, selective etherification of only isoprene (first reaction) using a specific catalyst in the C5 fraction is performed to remove the problem caused by adopting extractive distillation from the C5 oil fraction in the isoprene separation technique. (Second reaction) by using a specific catalyst, and the present applicant has proposed a process for separating isoprene by using a method as described in Patent Application No. 2011-0126326, In Application No. 2012-0047142, a method of selectively alkoxylating a diene compound having 4 to 5 carbon atoms in C5 fraction has been proposed. This prior application of the present applicant discloses the first reaction of the reaction extraction process and relates to the conversion of isoprenyl to isoprenyl-methylether, as disclosed in U.S. Patent No. 5,120,868, Palladium catalyst, the method of obtaining isoprene by oxidative dehydrogenation reaction of 2-methyl-1-butene disclosed in U.S. Patent No. 4,108,918, US Patent No. 4,843,180 And an overall diene conversion method. However, U.S. Patent No. 5,120,868 does not show the selectivity for the introduction position of the alkoxy group added to the diene compound, and U.S. Patent No. 4,843,180 can be applied after the selective alkoxylation reaction of the diene compound And U.S. Patent No. 4,843,180 has a problem that the reaction time is also very long because the process is limited to methoxylation with a focus on butadiene which is not isoprene, and the inventors of the present invention have proposed a different approach from these prior patents The first reaction was proposed to isolate isoprene from the C5 oil by the reaction extraction method.

Therefore, the technique of separating isoprene by selectively etherifying (first reaction) only isoprene in C5 hydrocarbon using C5 oil by reaction extraction method and then de-etherating (second reaction) It is necessary to formulate them integrally in the C2 to C5 olefin production process.

As described above, isoprene, cyclopentadiene, piperrylene and the like, which are about 10 to 18% of the undervalued C5 oil as a dancing resource, can be used for synthesizing isobutylene-isoprene rubber, And the other C5 oil fractions such as pentane, pentene and isopentane are known to have no utility value compared to other products.

In addition, existing technologies for recovering useful components such as isoprene, cyclopentadiene, piperylene and the like in C5 mixed oil produced as a by-product of naphtha crackers are based on multi-stage distillation using a multi-stage column or extractive distillation using an extractant In this case, the cost and the additional multi-stage separation process are disadvantageous from the economical point of view. The cost of the extraction and the use of the extracting agent in this case is disadvantageous in 15% of C5 oil content Only the existing isoprene is recovered and the remaining oil is not taken into consideration at all.

Natural gas crackers for obtaining ethylene from natural gas, which is comparatively less expensive than naphtha due to the rise in crude oil prices and heavy crude oil, have been added. However, since ethylene alone can be selectively produced, the supply and demand of propylene will be unbalanced, Unlike in the case of the rich countries where natural gas is abundant, most of the crude oil importers like Korea depend on naphtha cracking, which is very disadvantageous in terms of reduction of greenhouse gas emissions. In Korea, the amount of ethylene obtained from the naphtha cracking process reaches 5 million tons per year, and the amount of C5 oil discharged as a by-product reaches 700 thousand tons, but it can not be used effectively. Therefore, there is a high need for the development of ethylene / propylene feedstock control technology. For this purpose, a light olefin restructuring technology is required. Therefore, in the C5 oil produced from naphtha crackers, a double bond It is urgently required to develop a technique for collecting high olefins such as isoprene, piperylene, cyclopentadiene and the like and converting the remaining oils into light olefins.

DISCLOSURE OF THE INVENTION Accordingly, it is an object of the present invention to provide a process for recovering isoprene, piperylene and cyclopentadiene useful as olefins economically in C5 mixed oil produced after naphtha cracking, catalytically decompose the remaining oil, And to provide an integrated high-yielding method for producing light olefins such as ethylene and propylene.

It is also intended to establish ideal continuous process conditions for each detailed process in order to separate or decompose C5 mixed olefins generated after naphtha cracking to obtain C2 to C5 olefins with high purity.

In addition, a method of obtaining an alkyl ether compound used in the de-etherification reaction at the time of isoprene separation in C5 oil produced after naphtha cracking with optimum selectivity from C5 oil, And to provide a method for separating isoprene into industrially excellent efficiency by de-etherification.

In addition, ZSM-5 catalysts, which exhibit superior pore characteristics while retaining the physical and chemical properties of existing catalysts in the production of light olefins containing ethylene and propylene by catalytic catalytic cracking in C5 oil produced after naphtha cracking, And to provide a method capable of improving the production yield.

In order to solve the above-mentioned problems, the present invention provides a process for producing a naphtha product, which comprises: (a) extractively distilling C5 mixed oil from a C5 mixed oil product produced after a naphtha cracking process to obtain a first stream containing a paraffin compound, into a second stream comprising a diene compound; (b) dimerizing the cyclopentadiene contained in the second stream to produce a third stream comprising dicyclopentadiene; (c) separating the third stream into a fourth stream comprising dicyclopentadiene and piperylene and a fifth stream comprising isoprene; (d) recovering a stream comprising dicyclopentadiene, a stream comprising piperylene, and a residual stream from said fourth stream; (e) recovering isoprene from the fifth stream using a reactive extraction method; And (f) catalytically cracking the first stream to convert it to a stream comprising ethylene and propylene, to produce olefins of the range of 2 to 5 carbon atoms.

Also, the C5 mixed oil fraction may contain 20 to 60% by weight of a paraffin compound including n-pentane, isopentane and cyclopentane; 20 to 60% by weight of a diene compound comprising isoprene, cyclopentadiene and piperylene; And 10 to 50% by weight of the residual mixture comprising the monoene compound.

Also, in the step (a), the C5 mixed oil fraction is supplied to the middle of an extractive distillation column at a lower temperature of 80 to 200 ° C and a pressure of 1 to 20 atmospheric pressure, so as to be brought into contact with an extracting agent flowing upward, Characterized in that the stream is discharged and the second stream is discharged to the bottom of the column.

The extractant may be selected from the group consisting of acetonitrile (ACN), dimethylformamide (DMF), N-methylpyrrolidone (NMP), β-methoxypropionitrile ), Dimethylacetamide (DMAC), dimethylsulfoxide (DMSO), γ-butyrolactone (γ-BL), furfural, acetone and ionic liquids And at least one selected from the group consisting of

In addition, the extractant is recovered from the second stream in the recovery column and recycled to the extractive distillation column.

Also, the step (b) is performed in a continuous flow type reactor at a temperature of 40 to 110 ° C. and a temperature of 30 to 300 ° C. for 2 to 10 hours.

Further, in the step (c), the third stream flows into the middle of the first separation column, the fifth stream is discharged to the column top according to the difference in boiling point, and the fourth stream is discharged to the column bottom. to provide.

In addition, in the step (d), the fourth stream flows into the middle of the second separation tower so that the stream containing the piperylene is recovered on the column in accordance with the difference in boiling point, and the stream containing the dicyclopentadiene And the residual stream is recovered to the bottom of the column.

The step (e) further comprises: (e-1) selectively etherifying the isoprene in the fifth stream in the presence of an alcohol and an etherification catalyst to produce a sixth stream comprising an alkyl ether compound of isoprene ; (e-2) deethering an alkyl ether compound of the isoprene in the sixth stream in the presence of an inert gas and a de-etherification catalyst to produce a seventh stream comprising isoprene; And (e-3) separating isoprene from the seventh stream.

Further, the step (e-1) is carried out in an etherification catalytic reactor at a temperature of 50 to 250 ° C and a pressure of 0.5 to 10 atm.

Also, in the step (e-1), the sixth stream flows into the third separation column, and a stream containing unreacted isoprene and alcohol is recycled to the etherification catalytic reactor through the top of the column, Characterized in that the stream comprising the alkyl ether compound of isoprene and the residue slurry of the etherification catalyst is discharged to the bottom of the column.

In addition, the third separation column has a lower temperature of 40 to 100 ° C.

Also, the stream containing the alkyl ether compound of isoprene and the residue slurry of the etherification catalyst flows into the fourth separation tower, and the stream containing the alkyl ether compound of the isoprene is discharged into the column on the basis of the difference in boiling point. Characterized in that the stream comprising the residue slurry of the catalyst is recycled to the etherification catalytic reactor via the bottom.

In addition, the fourth separation column has a lower temperature of 80 to 200 ° C.

Further, the present invention provides a method characterized in that the alcohol is an alcohol having an alkyl group having 1 to 4 carbon atoms.

The etherification catalyst may be at least one selected from the group consisting of cobalt (Co), rhodium (Rh), iridium (Ir), palladium (Pd), ruthenium (Ru), nickel (Ni) ≪ / RTI > is a compound which comprises a compound of formula < RTI ID = 0.0 >

Also, the etherification catalyst is used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the isoprene.

Also, the step (e-2) is carried out in a de-etherification catalytic reactor, which is a heterogeneous gas phase reactor at a temperature of 100 to 300 ° C, a pressure of 1 to 5 atm and a space velocity of 0.5 to 10 h ^-1 . to provide.

In addition, in the step (e-2), the seventh stream flows into a flash drum, the inert gas is recycled to the deetherification catalytic reactor, and isobutylene, an alkyl ether compound of an unreacted isoprene, Is discharged separately from the inert gas.

Also, the stream containing the isoprene, the unreacted isoprene alkyl ether compound, and the alcohol is introduced into the fifth separation tower, the isoprene is recovered on the column in accordance with the difference in boiling point, and the alkyl ether compound of the unreacted isoprene and the alcohol Is recycled to the de-etherification catalytic reactor through the bottom of the column.

In addition, the fifth separation tower has a lower temperature of 40 to 100 ° C.

Further, the present invention provides a method characterized in that the inert gas is a nitrogen gas.

Further, the deetherification catalyst is a compound represented by the following general formula (1).

[Chemical Formula 1]

B, c, and d are integers, a / b is 1 to 10, and a / b is an integer of 1 to 10, and X is at least one element selected from the group consisting of zirconium (Zr) and titanium (Ti), Y is magnesium (Mg) c is an integer satisfying 5 to 30, and d is a valence of each element.

Also, the de-etherification catalyst is used in an amount of 1 to 10 parts by weight based on 100 parts by weight of the alkyl ether compound of the isoprene.

Further, the step (f) is carried out in a reactor in the presence of a catalytic cracking catalyst at a temperature of 300 to 700 ° C. and a space velocity of 1 to 20 h ^-1 .

Also, the catalytic cracking catalyst is a ZSM-5 catalyst prepared by using a carbon powder having nanoporous pore-forming ability or nanoporous particles as a template material.

Also provided is a process wherein the ZSM-5 catalyst is cationically substituted.

The method may further comprise 0.01 to 10 parts by weight of phosphorus precursor based on 100 parts by weight of the ZSM-5 catalyst.

Further, the ZSM-5 catalyst further comprises a rare earth metal or an alkali metal in an amount of 2 or less in terms of an atomic ratio to the phosphorus.

According to the present invention, piperalylene and cyclopentadiene can be economically recovered through one extraction distillation and dimerization process from C5 mixed oil produced after naphtha cracking, recovering isoprene in high purity and recovering the remaining residual oil by catalytic contact It is possible to provide an integrated method of optimum process conditions for producing light olefins containing ethylene and propylene efficiently by decomposition.

In addition, by using the reaction extraction method in the isoprene separation process from the C5 mixed oil, it is possible to solve the high energy consumption problem due to the separation of isoprene and the like through the conventional multi-stage distillation.

Also, it is possible to provide a new process which can be industrially applied in the isoprene separation technique using reaction extraction from C5 oil by suggesting a method of de-etherifying an alkyl ether compound selectively extracted using an optimally combined catalyst compound from C5 oil .

In addition, phosphorus and metals introduced by improving the diffusion of reactants and intermediates by using ZSM-5 catalyst having both fine and mesoporous porosity characteristics prepared from carbon as a template in a catalytic catalytic cracking process for producing light olefins The yield of the production of light olefins including ethylene and propylene can be improved from the C5 mixed oil.

It is also possible to control the acid and base properties of the catalyst by introducing phosphorus and a rare earth metal or an alkali metal into the ZSM-5 catalyst having fine and mesoporous pore characteristics, and having stable and excellent activity over a long period of time The production of light olefins including ethylene and propylene can be further improved from the C5 mixed oil by using the fine and mesoporous zeolite ZSM-5 catalyst.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic flow diagram illustrating a method for producing olefins ranging from 2 to 5 carbon atoms from a C5 blended oil fraction after a naphtha cracking process in accordance with an embodiment of the present invention. FIG.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims and their equivalents. It is to be understood that various equivalents and modifications may be substituted for those at the time of the present application.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic flow diagram illustrating a method for producing olefins in the range of 2 to 5 carbon atoms from a C5 blended oil fraction after a naphtha cracking process according to an embodiment of the present invention.

Referring to FIG. 1, the present invention provides a process for producing caffeine from a C5 mixed oil (C5) produced after a naphtha cracking process, comprising the steps of: (a) extracting the C5 mixed oil (C5) as a raw material by extractive distillation to obtain a paraffin compound Into a first stream (1) and a second stream (2) comprising a diene compound; (b) dimerizing the cyclopentadiene contained in the second stream (2) to produce a third stream (3) comprising dicyclopentadiene; (c) separating the third stream (3) into a fourth stream (4) comprising dicyclopentadiene and piperylene and a fifth stream (5) comprising isoprene; (d) recovering a stream (4a) comprising dicyclopentadiene, a stream (4b) comprising piperylene, and a residual stream (4c) from said fourth stream (4); (e) recovering isoprene from the fifth stream (5) using a reactive extraction method; And (f) converting the first stream (1) into a stream (1a) comprising ethylene and propylene by catalytic catalytic cracking to produce an olefin in the range of 2 to 5 carbon atoms .

In the present invention, the C5 mixed oil (C5) is a by-product in the existing naphtha cracking center, and is a paraffinic compound 20 having a carbon number of 5 and having a carbon number of 4 to 7 produced in the debutanizer column and the depentanizer column To 60% by weight; 20 to 60% by weight of a diene compound having 5 carbon atoms; And 10 to 50% by weight of a residual mixture comprising other mono-ene having 5 carbon atoms. The paraffin compound having 5 carbon atoms may include n-pentane, isopentane and cyclopentane. Examples of the diene compound having 5 carbon atoms include isoprene, cyclopentadiene, cyclopentadiene and piperylene, as well as 1,4-pentadiene and 2,3-pentadiene. Also, the residual mixture may include 1-pentene, 2-methyl-1-butene, 2-pentene, 2-methyl-2-butene), dimethylacetylene (dimethylacetylene) and some C4 compounds and C6 compounds.

In the present invention, the step (a) is a step of extracting and separating the diene compound in the C5 mixed oil (C5) by using the extractive distillation. The C5 mixed oil (C5) is supplied to the middle of the extractive distillation column (101) The first stream 1 rich in paraffin compounds such as n-pentane, isopentane, and cyclopentane is discharged from the top of the column to be brought into contact with the extractant E fed from the top of the column 1, and dicyclopentadiene, The second stream 2 rich in diene compounds such as piperylene and isoprene is discharged. The first stream (1) discharged to the column top is transferred to the catalytic cracking reactor, and a detailed description will be given later.

The operation conditions of the extractive distillation column 101 may be set at a temperature of 80 to 200 ° C. and a pressure of 1 to 20 atmospheric pressure in the lower part and preferably at a temperature of 100 to 160 ° C. and a pressure of 1 to 10 atm, The separation plate of the distillation column 101 may have a range of 80 to 250 stages, preferably 100 to 180 stages.

In the present invention, the diene compound extractant (E) used in the extractive distillation column (101) is not particularly limited. Examples thereof include acetonitrile (ACN), dimethylformamide (DMF), N-methylpyrrolidone (NMP), 棺 -methoxypropionitrile (MOPN), dimethylacetamide (DMAC), dimethylsulfoxide (DMSO) , γ-butyrolactone (γ-BL), furfural, acetone, an ionic liquid, a mixed extractant of these, or a mixture of these and water may be used, Nitrile, dimethylformamide or N-methylpyrrolidone may be used, and more preferably, dimethylformamide may be used.

At this time, the diene compound extractant (E) may be used in a weight ratio of 3 to 10 times, preferably 5 to 8 times, by weight based on the total weight of the C5 mixed oil component (C5) to be supplied.

The extractant (E) used for the extractive distillation in the extractive distillation column (101) is included in the second stream (2) and transferred to the recovery column (102). In the recovery column 102, the extracted diene compound rich stream 2a is transferred to the dimerization reactor 103 while the extractant E is withdrawn from the second stream 2 and passed through the extractive distillation column Lt; RTI ID = 0.0 > 101). ≪ / RTI > The method of separating the stream 2a containing the extractant E and the diene compound is not particularly limited and may be performed by setting the number of the recovering columns 102, the recycle ratio, and the temperature, if necessary.

In the present invention, the step (b) is a step of dimerizing the cyclopentadiene contained in the second stream (2) into dicyclopentadiene, and the diene compound rich stream (2a ) Is cyclized to dicyclopentadiene at a conversion of at least about 90%, preferably at least 95%, to produce a third stream (3) comprising dicyclopentadiene.

The dimerization reaction can be carried out in a continuous flow type reactor at a temperature of 40 to 110 ° C and 30 to 300 ° C for 2 to 10 hours. If necessary, the temperature and pressure of the reactor can be controlled. May be possible.

In the present invention, the step (c) is a step of separating isoprene from the third stream (3). The third stream (3) flows into the middle part of the first separation column (104) The fifth stream 5 rich in isoprene which is low in boiling point is discharged, and the fourth stream 4 containing the dicycloheptadienes, piperylenes, piperylenes and some oligomers thereof, which are dimerized at a high boiling point, is discharged. At this time, the first separating tower 104 can follow the simple distillation using the boiling point difference, and the number of the separation tower, the number of separation plates and the like can be set in consideration of sufficient separation, .

In the present invention, step (d) is a step of recovering dicyclopentadiene and piperylene, which are useful materials, and the fourth stream (4) flows into the middle part of the second separation column (105) Rich stream 4b having a low boiling point is recovered and a stream 4a rich in dicyclopentadiene having a high boiling point at the side is recovered and a residual stream 4c containing a diene compound or the like not separated into a bottom stream is recovered, Is recovered. At this time, the residual stream 4c may be recycled to the first separation column 104 together with the third stream 3, or recirculated to the second separation column 105 together with the fourth stream 4 . At this time, the second separation tower 105 can also be subjected to the simple distillation using the boiling point difference, and the number of the separation tower, the number of separation plates, and the like can be set in consideration of sufficient separation, have.

In the present invention, the step (e) may further comprise the step of separating the fourth stream (4) containing dicyclopentadiene and piperylene from the fifth stream (5) enriched in isoprene from the first separation column (104) The step of recovering isoprene, and the step of recovering isoprene using the reaction extraction method according to the present invention will now be described in more detail.

In the reaction extraction method according to the present invention, the fifth stream (5) is selectively etherified (first reaction) with an alcohol in the presence of an etherification catalyst to selectively form an alkyl ether compound of isoprene, And then dealkylating the alkyl ether compound in the presence of a de-etherification catalyst (second reaction) to recover highly pure isoprene. For example, step (e) may comprise (e-1) selectively etherifying the isoprene in the fifth stream (5) in the presence of an alcohol and an etherification catalyst to form a sixth stream 6 comprising an alkyl ether compound of isoprene ); (e-2) de-etherifying the alkyl ether compound of isoprene in the sixth stream (6) in the presence of an inert gas (G) and a de-etherification catalyst to produce a seventh stream (7) comprising isoprene step; And (e-3) separating isoprene from the seventh stream (7).

The step (e-1) may be performed in the etherification catalytic reactor 106 at a temperature of 50 to 250 ° C and a pressure of 0.5 to 10 atm.

In the step (e-1), the sixth stream (6) flows into the third separation column (107), and the stream (6b) containing unreacted isoprene and alcohol due to the difference in boiling point is subjected to the etherification The stream 6a recycled to the catalytic reactor and comprising the alkyl ether compound of isoprene and the residue slurry of the etherification catalyst is discharged to the bottom of the column. At this time, it is preferable that the third separation column 107 has 1 to 40 separation plates, and the lower temperature is 40 to 100 ° C.

In addition, the stream 6a containing the alkyl ether compound of isoprene and the residue slurry of the etherification catalyst flows into the fourth separation tower 108, and the stream containing the alkyl ether compound of the isoprene as a top- The stream 6d containing the residue slurry of the etherification catalyst may be recycled to the etherification catalytic reactor 106 through the bottom. At this time, it is preferable that the fourth separation tower 108 has 1 to 20 separation plates, and the lower temperature is 80 to 200 ° C.

Generally, in order to alkoxylate a C5 diene compound such as isoprene with an alkyl ether compound, an etherification reaction in which an alcohol (C _n H _{2n + 1} OH) is added is required. For example, when an alkonylation reaction is carried out using isoprene represented by the following formula (2), an alcohol is added to at least one of the carbon positions 1 to 4 of isoprene to generate various kinds of alkyl ether compounds .

(2)

If an alkoxy group (OC _n H _{2n + 1} ) is introduced to the carbon site except for the number 2, it is difficult to convert it to isoprene again due to the structural change of the compound. In contrast, when an alkoxy group is introduced Can be converted into an isoprene compound through a chemical reaction. Therefore, it is useful to selectively isolate or purify only isoprene.

In the present invention, when the isoprene in the fifth stream (5) is converted into an alkyl ether compound, a specific alcohol and an etherification catalyst may be used in order to selectively introduce an alkoxy group into the 2-carbon site.

First, an alcohol (ROH) having a carbon number of 1 to 4 is added to the fifth stream (5) in the presence of an etherification catalyst to selectively introduce an alkoxy group (-OR) into the second carbon position of the isoprene in the fifth stream Can be introduced. If the number of carbon atoms of the alcohol (ROH) exceeds 4, it may be difficult to introduce an alkoxy group into isoprene due to steric hindrance. The alcohol (ROH) usable herein may be at least one alcohol selected from alcohols having 1 to 4 carbon atoms, and examples thereof include methanol, ethanol, propanol, isopropanol, butanol and isobutanol , Preferably methanol or ethanol, more preferably methanol.

The alcohol (ROH) may be used in an amount of 30 to 85 parts by weight, preferably 40 to 60 parts by weight, based on 100 parts by weight of the etherification reaction product. When the above-mentioned alcohol (ROH) is used in an excessive amount, an alkoxy group derived from alcohol (ROH) can be introduced into the carbon sites of isoprene selectively, so that the content of alcohol (ROH) It is possible to reduce the recovery cost due to the alcohol recovery and increase the efficiency.

In addition to the kind and content of the alcohol (ROH), the reaction activity for selective alkyl ether conversion can be further enhanced by adopting a specific noble metal catalyst having high activity as the etherification catalyst in the present invention. As such an etherification catalyst, for example, a compound selected from the group consisting of Co, Rh, Ir, Pd, Ru, Ni, A compound containing more than two species may be used, and preferably a combination of a compound containing a rhodium compound or a cobalt compound and other components may be used. Such a catalyst compound can be used in the form of a salt such as a nitrate, a chloride, a nitrate, a sulfate or the like, or a transition metal complex.

The etherification catalyst may be composed of only the metal components, and may be used in a form supported on a conventional catalyst carrier known in the art. The catalyst carrier is used to broadly disperse the active component using a large surface area and to improve the physical properties such as thermal and mechanical stability difficult to obtain with only the catalyst component. For example, Coating method can be applied. The catalyst support may be porous carbon, inorganic or metal oxide, ion exchange resin, etc. The catalyst support may be used in an amount ranging from 1 to 95% by weight, preferably from 2 to 90% by weight, based on the catalyst composition . As the porous carbon, activated carbon, carbon fiber, graphite fiber, carbon nano-nib and the like can be used. As the inorganic material, silica, alumina, zeolite and the like can be used. As the metal oxide, metal oxides such as tungsten, titanium, nickel, ruthenium, tantalum, and cobalt may be used.

The amount of the etherification catalyst to be used is not particularly limited, but may be 0.1 to 10 parts by weight based on 100 parts by weight of isoprene. If the catalyst content is less than 0.1 part by weight, the desired selective alkyl ether conversion reaction may be delayed. If the catalyst content exceeds 10 parts by weight, the reaction rate may be accelerated but the carbon position selectivity of the alkoxy group introduced into isoprene may be lowered.

The step (e-2) may be carried out under the conditions of a temperature of 100 to 300 ° C, a pressure of 1 to 5 atm and a space velocity (WHSV, space velocity when the liquid is supplied) of 0.5 to 10 h ^-1 , Etherification catalytic reactor 109, which is a heterogeneous gas phase reactor at a pressure of 1 to 2 atmospheres and a space velocity of 1 to 2 h < ^-1 >.

In the step (e-2), the seventh stream 7 flows into the flash drum 110 so that the inert gas G is recycled to the de-etherification catalytic reactor 109, and the isoprene, A stream 7a containing an alkyl ether compound of an unreacted isoprene and an alcohol is discharged separately from the inert gas (G).

Also, the stream 7a containing the isoprene, the unreacted isoprene alkyl ether compound and the alcohol flows into the fifth separation tower 111, and the isoprene 7b is recovered on the top according to the difference in boiling point. The stream 7c comprising the alkyl ether compound of the reacted isoprene and the alcohol can be recycled to the de-etherification catalytic reactor 109 via the bottom. At this time, it is preferable that the lower temperature of the fifth separation tower 111 is 40 to 100 ° C.

Since the transition metal catalyst is used in the de-etherification reaction (second reaction) performed in the step (e-2), an inert gas (G) such as nitrogen or argon is used as a carrier gas to prevent ignition, So that the alkyl ether is converted to isoprene and methanol through the deetherification catalyst bed.

In the present invention, the deetherification catalyst used in the de-etherification (second reaction) may be a compound represented by the following general formula (3).

(3)

B, c, and d are integers, a / b is 1 to 10, and a / b is an integer of 1 to 10, and X is at least one element selected from the group consisting of zirconium (Zr) and titanium (Ti), Y is magnesium (Mg) c is an integer satisfying 5 to 30, and d is a valence of each element.

In order to maximize the improvement of the alkyl ether conversion and selectivity of isoprene in the deetherification reaction in the deetherification catalyst compound constitution, it is preferable to select titanium (Ti) as the X component and magnesium (Mg) as the Y component, It is preferable that the ratio a / b is 1 to 3 and the ratio a / c is 10 to 20.

The deetherification catalyst compound used in the present invention may be prepared by using a precursor for each constituent element. For example, the deetherification catalyst compound may be a compound selected from the group consisting of colloidal silica, zirconium (Zr) Titanium tetrachloride as a titanium (Ti) source, magnesium nitrate as a magnesium (Mg) source, and calcium acetate as a calcium (Ca) source may be used, but the present invention is not limited thereto. After the precursors are selected and distilled water is added, excess ammonia water is added to produce a gel type catalyst, and then the resulting catalyst is filtered and dried at 100 to 120 ° C for about 12 to 36 hours And then calcined at 500 to 700 ° C to prepare a de-etherification catalyst.

The deetherification catalyst may be composed of only the above components and may be used in a form supported on a conventional catalyst carrier known in the technical field of the present invention. The same applies to the catalyst.

The amount of the deetherification catalyst to be used is not particularly limited, but may be 1 to 10 parts by weight, preferably 2 to 5 parts by weight, based on 100 parts by weight of the alkyl ether compound of isoprene. If the amount of the catalyst is less than 1 part by weight, the de-etherification reaction time may be relatively long. If the amount of the catalyst is more than 10 parts by weight, the conversion of alkyl ether and the selectivity to isoprene may be decreased.

In step (e-3), the high-purity isoprene stream 7b is recovered from the seventh stream 7 generated by the de-etherification reaction through the flash drum 110 and the fifth separation tower 111, Can be separated.

In the present invention, the step (f) is a step of converting the first stream (1) discharged to the upper portion of the extractive distillation column (101) into the stream (1a) containing ethylene and propylene, To 700 < 0 > C and a space velocity of 1 to 20 h < ^-1 >. Hereinafter, in the present invention, a catalytic cracking catalyst (ZSM-5 catalyst) used in a method for producing light olefins including ethylene and propylene from the first stream (1) This will be described in more detail. In the description of the catalytic cracking catalyst and the production method thereof, the term "micropores" refers to a characteristic in which a general ZSM-5 catalyst has a pore size (diameter) of 1 nm or less in consideration of having micropores of about 1 nm or less Quot; medium porosity "means that the pore size (diameter) has a pore size of at least 1 nm, preferably at least 2 nm. However, the pore size value is not strict and may refer to a relative value depending on catalyst production conditions and the like. However, the "medium pores" according to the present invention will be described below as pores having a pore size (diameter) of 2 nm or more.

In the present invention, the catalytic cracking catalyst is a ZSM-5 catalyst prepared using a material having a capability of forming a medium pore structure as a template material, and has both fine and mesoporous characteristics. The catalytic properties are such that diffusion of reactants and intermediate products The production yield of light olefins including ethylene and propylene can be improved from the C5 mixed oil.

The catalytic cracking catalyst prepared using the above material having a medium pore forming ability as a template material may be prepared by, for example, (A) aging a mixed solution containing a silica precursor and an aluminum precursor to form a gel; (B) adding a template having a medium pore forming ability to the gel by heat treatment, agitating and aging the gel; (C) crystallizing the aged mixture in the step (B) to form a solid product; And (D) heat treating the solid product to remove the template material.

The mixed solution of step (A) may be prepared by: (A-1) dissolving monovalent metal hydroxide and tetrapropylammonium halide in distilled water; (A-2) adding the silica precursor to form a homogeneous mixture; And (A-3) dropping the aluminum precursor in a liquid state to the homogeneous mixture. The monohydric metal hydroxide may be sodium hydroxide (NaOH), potassium hydroxide (KOH) or the like. The tetrapropylammonium halide may be tetrapropylammonium bromide, tetrapropylammonium chloride, The aluminum precursor may be sodium aluminate (NaAlO ₂ ), aluminum nitrate (Al (NO ₃ ) ₃ ), aluminum secondary-aluminum nitrate, or the like. But are not limited to, aluminum sec-butoxide, aluminum tert-butoxide, aluminum tri-sec-butoxide, aluminum tri- tert-butoxide, aluminum ethoxide, and aluminum isopropoxide. This may be used.

The template material of step (B) has a capability of forming a medium pore structure upon heat treatment of the catalyst after the addition. As a mold material having such a capability of forming a medium pore structure, there is a soft template such as a surfactant and a hard template such as a carbon or a polymer material. However, when the hard mold material is removed by thermal decomposition or the like Easy to control the morphology, can produce materials having larger pores, and is less expensive than the flexible mold material. Carbon powders or nano-sized polymer particles may be used as the hard mold material, and they may be appropriately selected in combination in consideration of ease of obtaining the mold material, structural control aspect, and the like. That is, in the case of carbon powder, it is relatively easy to obtain products having various shapes and particle sizes as a commercialized product, and it is easy to store and handle. In the case of nanoporous polymer particles, the thermal decomposition temperature is lower than that of carbon powder, It is advantageous in terms of structure control.

The carbon powder or nano-polymer particles used as the template material is not limited as long as it can form mesopores, and may be, for example, spherical, square, rectangular, cylindrical or the like. However, it is preferable that the size (diameter) is 2 to 50 nm in consideration of the smooth adsorption / desorption of the C5 mixed oil component as the catalyst catalytic cracking reactant to the catalytic active site.

The nanoporous polymer particles are not limited as long as they have a capability of forming a medium pore structure upon heat treatment after the addition of the catalyst. Examples of the nanoporous polymer particles include polycarbonate, polystyrene, polyethylene, polypropylene poly (ethylene oxide), poly (propylene oxide), polylactide, poly (methyl methacrylate) (poly (methyl methacrylate) Etc. may be used, and preferably polycarbonate or polystyrene having little residue at the time of removal by thermal decomposition may be used.

In addition, the template material can develop medium pores in proportion to the amount added. And the content thereof may be 5 to 80 parts by weight based on 100 parts by weight of the silica precursor. If the amount of the template material is less than 5 parts by weight, the formed mesopore volume may not be satisfactory. If the amount of the template material is more than 80 parts by weight, the catalyst activity point may be decreased and the catalytic activity may be lowered. However, even though the mesopore characteristics are improved by the addition of a large amount of the template material and the subsequent removal of the calcination, improvement in the reaction activity of the catalyst due to the relaxation of the molecular diffusion restriction due to the size of the adsorption / desorption space of the C5 mixed oil, reaction product, It becomes non-proportional. That is, as a result of closely observing the content of the carbon powder (KetjenBlack) in the added template material, the present inventors have found that the reaction activity of the catalyst is increased up to 80 parts by weight with respect to 100 parts by weight of the silica precursor, The degree of improvement of the reaction activity of the catalyst is not conspicuous.

The crystallization in the step (C) may be carried out by a generally used method, for example, hydrothermal synthesis, microwave synthesis, dry-gel synthesis or the like. Through this crystallization, the zeolite grows into a large single crystal surrounding the carbon or nanoporous polymer particles as a template material. Thereafter, the solid product is heat-treated to remove the template material as in the step (D), whereby the zeolite single crystal structure can retain the mesopores formed from carbon.

In the present invention, it is preferable that the catalytic cracking catalyst is prepared by performing cation exchange with respect to the solid product heat-treated in the step (D). The cation substitution is for exchanging zeolite generally substituted with sodium ion (Na ⁺ ) with a proton (H ⁺ ), and the zeolite catalyst substituted with a proton is more effective in cracking reaction because acid strength is increased compared to other cations. The cationic substitution can be carried out by adding the solid product to a cationic substitution solution at 70 to 90 ° C and stirring at the same temperature, and the cation-substituted aqueous solution is further subjected to filtration and washing for 1 to 3 times The cation exchange process may be repeated. The solution used in such cation exchange, the ammonium nitrate (NH ₄ NO _3), ammonium chloride (NH ₄ Cl), the group consisting of ammonium carbonate _{((NH 4) 2 CO 3} ) and ammonium fluoride (NH ₄ F) 1 < / RTI >

In addition, the catalytic cracking catalyst can be produced by further performing heat treatment on the cation-substituted solid product. The heat treatment may be performed by firing at 400 to 700 ° C for 3 to 10 hours. If the heat treatment temperature is less than 400 ° C, the ammonium salt that is primarily substituted in the zeolite catalyst may not be sufficiently removed, so that the acid strength of the zeolite may decrease. If the temperature exceeds 700 ° C, the catalyst collapse and the Bronsted acid point . If the heat treatment temperature is less than 3 hours, it may be difficult to remove sufficient ammonium salt, and if it exceeds 10 hours, power loss may occur. Here, it is preferable that the cation-substituted solid product is dried at 100 to 120 ° C for 5 to 15 hours before the heat treatment, and then the heat treatment is performed.

In the present invention, the catalytic cracking catalyst may be used as a phosphor modified ZSM-5 catalyst by introducing a phosphorus precursor into the solid product heat-treated in the step (D).

The impregnation of the phosphorus precursor may be performed by a method of impregnating the ZSM-5 catalyst, for example, by hydrating the phosphorus precursor into water, adding the solid product heat-treated in the step (D) to the hydrated solution, drying and heat- . In this case, it is important that the phosphorus precursor introduction amount is set to an optimum range with respect to the amount of the ZSM-5 catalyst to be produced and the amount of carbon deposition according to the catalytic reaction. Therefore, It is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 3 parts by weight, still more preferably 0.1 to 1.5 parts by weight, even more preferably 0.1 to 1 part by weight, based on 100 parts by weight of the porous ZSM- Most preferably by weight.

To the precursor, for example, phosphoric acid (H ₃ PO _4), ammonium phosphate ((NH ₄₎ H ₂ PO _4), phosphoric acid ammonium ((NH _{4) 2} HPO _4), tricalcium phosphate, ammonium ((NH ₄ ) ₃ PO ₄ ) and the like can be used.

In the present invention, the catalytic decomposition catalyst may be used as a modified ZSM-5 catalyst capable of controlling the acid and base characteristics of the catalyst by introducing a rare earth metal or an alkali metal after introducing the phosphorus precursor.

The introduction of the rare earth metal or alkali metal may be carried out by impregnating the ZSM-5 catalyst with a rare earth metal precursor or an alkali metal precursor as in the case of the phosphorus introduction. At this time, it is important that the content of the rare earth metal precursor or the alkali metal precursor is set in an optimal range with respect to the amount of acid, the amount of the base and the amount of carbon deposition according to the catalytic reaction of the final prepared ZSM-5 catalyst. , It is preferable to introduce 2 or less in atomic ratio to phosphorus, more preferably 0.1 to 1.5 in atomic ratio, most preferably 0.5 to 0.9 atomic ratio.

As the rare earth metal contained in the rare earth metal precursor, lanthanum (La), Ce, Pr, Ne, Prommium, Sm, At least one member selected from the group consisting of terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thorium (Tm), ytterbium (Yb) and lutetium (Lu) Lanthanum may be selected. The alkali metal contained in the alkali metal precursor may include at least one selected from the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb) and cesium (Cs) Preferably potassium, rubidium, and cesium, and more preferably, cesium can be selected. For example, when lanthanum is selected as the rare earth metal, lanthanum nitrate (La (NO ₃ ) ₃ .6H ₂ O) can be introduced in the form of a precursor. When lithium is selected as the alkali metal, lithium nitrate (LiCO ₃ ) .

Test Example

The process was carried out according to the process shown in FIG. 1 to verify the effect of the method of producing olefins having 2 to 5 carbon atoms from the C5 mixed oil (C5) produced after the naphtha cracking process of the present invention. The composition of the C5 mixed oil (C5) produced after the naphtha cracking process initially supplied to the extractive distillation column (101) is shown in Table 1 together with the boiling point of each component. The above composition may be somewhat different according to the actual plant operating conditions. In this test example, the composition of the top portion of the naphtha cracker depentanizer is shown.

(1) Extraction distillation of C5 mixed oil

In the extractive distillation step performed using the crude C5 mixed oil (C5) having the composition shown in Table 1 as a feedstock, the total distillation column 116 stage extracting column 101 was used, and the extractant (E) was dimethylformamide Was fed into the 12th tray at a weight ratio of 7 times the weight of the crude C5 oil (C5), and the crude C5 oil (C5) was injected into the 40th tray. The bottom temperature of the tower was 48 캜 and the pressure in the tower was 2.7 atm. The compositions of the first stream (1) and the second stream (2) having passed through the extractive distillation column (101) after completion of the process are shown in Table 2 below.

Referring to Table 2, it can be confirmed that most diene compounds are extracted by the extractant (E) through extractive distillation.

(2) High purity dicyclopentadiene and piperylene recovery

In the second stream 2 transferred to the recovery column 102 the extractant E is recovered and recycled 2b to the extractive distillation column 101 and the remaining second stream 2a ) Was subjected to a dimerization reaction process in a continuous flow reactor (103) at a reaction temperature of 70 to 80 ° C and a reaction pressure of 80 to 100 ° C to produce a third stream (3). Thereafter, the fifth stream 5 and the fourth stream 4 are discharged to the top of the tower in accordance with the difference in boiling point in the first separation tower 104 and the fourth stream 4 is discharged from the second separation tower 105 The separated piperidine-rich stream (4b), the dicyclopentadiene-enriched stream (4a) and the bottom stream (4c) were recovered from the top of the column. The compositions of the fifth stream 5, the third stream 3, the piperylene-rich stream 4b, the dicyclopentadiene-enriched stream 4a, and the residual stream 4c passed after the completion of the process are shown in Table 3 below .

Referring to Table 3 above, in the dimerization reactor 103, the cyclopentadiene is dimerized to dicyclopentadiene at a conversion rate of 95% or more, most of the isoprene is separated in the first separation column 104, It can be confirmed that high purity piperrylene and dicyclopentadiene are recovered through the column 105.

(3) High purity isoprene recovery according to the reaction extraction process

The fifth stream 5 separated in the first separation column 104 is introduced into the etherification catalytic reactor 106 under the conditions of a reaction temperature of 100 ° C and a reaction pressure of 1 atm, 50 parts by weight of methanol and 0.5 part by weight of a rhodium complex were charged in an etherification reaction for 3 hours to obtain a sixth solution containing an alkyl ether compound (CH ₃ CCH ₃ (OC ₂ H ₅ ) CH ₂ CH ₃ ) Stream 6 was generated. The sixth stream 6 flows into a third separation column 107 having 15 separator plates at a lower temperature of 60 to 70 ° C, and unreacted isoprene and methanol-containing stream 6b due to a difference in boiling point And recycled to the etherification catalytic reactor 106 via the overhead, stream 6a containing the alkyl ether compound and the residue slurry of the etherification catalyst was discharged to the bottom. Thereafter, a stream 6c containing an alkyl ether compound is discharged to the column top in accordance with the difference in boiling point in the fourth separation tower 108 having 10 separation columns and a lower temperature of 120 to 130 ° C, and a stream (6d) is recycled to the etherification catalytic reactor (106) via the bottom.

The stream 6c containing the alkyl ether compound discharged through the column top in the fourth separation tower 108 is passed through a deethoxylation reactor having a reaction temperature of 200 캜, a reaction pressure of 1 atm and a space velocity of 1.2 h ^-1 (Si _a Ti _b Mg _c composite oxide, a / b = 2, a / c = 17) based on 100 parts by weight of the stream 6c containing the alkyl ether compound ) Was added in a predetermined amount and a de-etherification reaction was carried out in a nitrogen gas atmosphere to produce a seventh stream (7) containing isoprene. The seventh stream 7 then flows into the flash drum 110 so that the nitrogen gas G is recycled to the de-etherification catalytic reactor 109 and the bottom temperature of the seventh stream component 7a, After separation from the unreacted alkyl ether compound (7c) in the fifth separation tower (111) at 80 ° C according to the difference in boiling point, the hydrophilic component was finally removed using water to recover isoprene (7b). The composition of the sixth stream 6 after the completion of the etherification reaction, the seventh stream 7 after completion of the de-etherification reaction, and the final recovered stream 7b from which the hydrophilic component has been removed is shown in Table 4 below.

Referring to Table 4 above, most of the isoprene is selectively converted to the alkyl ether compound through the etherification reaction, and most of the alkyl ether compound is converted back to isoprene through the de-etherification reaction, and isoprene of 97% It can be confirmed that it is recovered.

(4) Production of light olefins by catalyst catalytic cracking process

The first stream 1 discharged to the upper portion of the extractive distillation column 101 is introduced into the fixed bed reactor 112 and the ZSM-5 catalysts (Cat.1 to Cat.3) And the catalyst was activated with nitrogen gas (40 ml) at 500 ° C for 1 hour before the reaction. After the catalytic activation, the reaction proceeded as the reactants passed through the catalyst bed in the reactor continuously. The weight hourly space velocity (WHSV) of the reactant was maintained at 3.5 h < ^-1 >, and the catalytic catalytic cracking reaction temperature of the first stream (1) was set at 600 < 0 > C. The products produced after the reaction were analyzed by gas chromatography. The conversion of the C5 fraction (first stream) and the selectivity and yield of light olefins (ethylene + propylene) were calculated according to the following equations The results are shown in Table 5 below.

[Preparation of catalytic decomposition catalyst]

Cat .One

1.6 g of sodium hydroxide (Samchun Chem.) Was added to and dissolved in 150 ml of distilled water. To this aqueous solution was added 2.28 g of tetrapropylammonium bromide (TPABr, Sigma-Aldrich) as a ZSM- Stir until dissolved. Colloidal silica (Ludox HS-40, Sigma-Aldrich) was slowly added dropwise to an aqueous solution containing sodium hydroxide and TPABr, and then stirred at room temperature until a homogeneous mixture was formed. On the other hand, 0.78 g of sodium aluminate (NaAlO ₂ , manufactured by Junsei) was dissolved in 30 ml of another distilled water and stirred for 1 hour. The resulting solution was slowly added dropwise to a solution containing a silica precursor (colloidal silica) Lt; / RTI > and stirred for a period of time to form a gel. Carbon powder (EC600JD, KetjenBlack) used as a template material was dried in an oven at 110 DEG C for 3 hours, and then added to the gel in a proportion of 45 parts by weight based on 100 parts by weight of the silica precursor. Lt; / RTI > The stirred solution was then subjected to hydrothermal synthesis at 160 ° C for 72 hours in an autoclave. After the hydrothermal synthesis, the resulting product was filtered, washed several times with distilled water, and the washed solid sample was dried at 110 ° C for 10 hours. The solid product produced after drying was crushed and calcined at 650 ° C. for 10 hours to remove carbon as a template material. 100 ml of 1 molar ammonium nitrate (Junsei) was prepared for cation exchange with the solid product after calcination, and the mixture was maintained at 80 ° C. 4 g of solid product was added thereto and stirred at 80 ° C for 3 hours. The cation-exchanged aqueous solution was subjected to filtration and washing, and an additional two cation exchange procedures were carried out. The cation-substituted solid product was dried at 110 ° C. for 10 hours and then calcined at 650 ° C. for 5 hours to prepare fine and mesoporous ZSM-5 catalysts.

Cat .2

A phosphorus precursor quantitated to be 0.3 parts by weight based on 100 parts by weight of the ZSM-5 catalyst finally prepared in the ZSM-5 catalyst prepared in Cat.1 was impregnated by the impregnation method. To this end, the quantified phosphoric acid (85%, Sigma-Aldrich) was dissolved in 10 ml of distilled water and stirred at 60 ° C for 10 minutes. Then, 1 g of the ZSM-5 catalyst prepared according to Cat.1 was introduced and sufficiently impregnated Gt; 60 C < / RTI > After all the distilled water was evaporated, it was dried in an oven at 100 ° C for 12 hours and then calcined at 650 ° C for 3 hours to prepare a fine and mesoporous ZSM-5 catalyst.

Cat .3

A lanthanum precursor quantitatively determined to have a lanthanum / phosphorus atom ratio of 0.3 was selected by introducing lanthanum (La) among the rare earth metals into ZSM-5 catalyst prepared in Cat.2 by impregnation method. To this end, lanthanum nitrate (La (NO ₃ ) ₃ .6H ₂ O, Sigma-Aldrich) was dissolved in 10 ml of distilled water and stirred at 60 ° C for 10 minutes. 1 g of the catalyst prepared in Cat.2 Lt; RTI ID = 0.0 > 60 C. < / RTI > After all the distilled water was evaporated, it was dried in an oven at 100 ° C for 12 hours and then calcined at 650 ° C for 3 hours to prepare a fine and mesoporous ZSM-5 catalyst.

Referring to Table 5, it can be seen that by using the ZSM-5 catalyst prepared by using the carbon powder according to the present invention as the template material for the first stream (1) separated from the extractive distillation column 101, the C5 oil conversion rate is 90% And the production yield of ethylene and propylene is 50% or more. When the phosphorus is introduced into the ZSM-5 catalyst or phosphorus and rare earth metals are introduced, the yield of the production is further improved. . On the other hand, the results according to Table 5 are obtained for the stream obtained after the catalytic cracking reaction. When the high boiling point material 1b is removed by passing through the subsequent separation tower 113, the light olefin stream having a higher ethylene and propylene yield 1c can be recovered.

While the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, Such modifications and changes are to be considered as falling within the scope of the following claims.

1: first stream 2: second stream
3: third stream 4: fourth stream
5: fifth stream 6: sixth stream
7: seventh stream 101: extractive distillation column
102: recovery tower 103: dimerization reactor
104: first separation tower 105: second separation tower
106: etherification catalytic reactor 107: third separation tower
108: Fourth Separation Tower 109: De-etherification Catalytic Reactor
110: flash drum 111: contact decomposition reactor
C5: C5 mixed oil E: Extractant
ROH: alcohol G: inert gas

Claims (29)

A process for producing olefins in the range of 2 to 5 carbon atoms from C5 mixed olefins produced after the naphtha cracking process,
(a) extractively distillating the C5 mixed oil into a raw material to separate a first stream containing a paraffin compound and a second stream containing a diene compound;
(b) dimerizing the cyclopentadiene contained in the second stream to produce a third stream comprising dicyclopentadiene;
(c) separating the third stream into a fourth stream comprising dicyclopentadiene and piperylene and a fifth stream comprising isoprene;
(d) recovering a stream comprising dicyclopentadiene, a stream comprising piperylene, and a residual stream from said fourth stream;
(e) recovering isoprene from the fifth stream using a reactive extraction method; And
(f) catalytically cracking the first stream to convert it to a stream comprising ethylene and propylene. The method according to claim 1,
The C5 mixed oil fraction contains 20 to 60% by weight of a paraffin compound including n-pentane, isopentane and cyclopentane; 20 to 60% by weight of a diene compound comprising isoprene, cyclopentadiene and piperylene; And 10 to 50% by weight of the residual mixture comprising the monoene compound. The method according to claim 1,
In the step (a), the C5 mixed oil is supplied to the middle of an extractive distillation column at a lower temperature of 80 to 200 ° C and a pressure of 1 to 20 atmospheric pressure to be brought into contact with an extracting agent flowing into the upper part, And the second stream is discharged to the bottom of the column. The method of claim 3,
The extraction agent may be selected from the group consisting of acetonitrile (ACN), dimethylformamide (DMF), N-methylpyrrolidone (NMP), β-methoxypropionitrile (MOPN) (DMAC), dimethylsulfoxide (DMSO), γ-butyrolactone (γ-BL), furfural, acetone and ionic liquids. ≪ RTI ID = 0.0 > and / or < / RTI > The method of claim 3,
Characterized in that the extractant is recovered from the second stream in the recovery column and recycled to the extractive distillation column. The method according to claim 1,
Wherein the step (b) is carried out in a continuous flow reactor at a temperature of 40 to 110 ° C and a temperature of 30 to 300 ° C for 2 to 10 hours. The method according to claim 1,
Wherein the third stream flows into the middle of the first separation column to discharge the fifth stream to the column top according to a difference in boiling point, and the fourth stream is discharged to the column bottom. The method according to claim 1,
In the step (d), the fourth stream flows into the middle of the second separation tower, and the stream containing the piperylene is recovered in the column on the basis of the difference in boiling point, and the stream containing the dicyclopentadiene is recovered to the side , And the residual stream is recovered to the bottom of the column. The method according to claim 1,
The step (e)
(e-1) selectively etherifying the isoprene in the fifth stream in the presence of an alcohol and an etherification catalyst to produce a sixth stream comprising an alkyl ether compound of isoprene;
(e-2) deethering an alkyl ether compound of the isoprene in the sixth stream in the presence of an inert gas and a de-etherification catalyst to produce a seventh stream comprising isoprene; And
(e-3) separating isoprene from the seventh stream;
≪ / RTI > 10. The method of claim 9,
Wherein the step (e-1) is carried out in an etherification catalytic reactor at a temperature of 50 to 250 DEG C and a pressure of 0.5 to 10 atm. 11. The method of claim 10,
In the step (e-1), the sixth stream flows into the third separation column, and the unreacted stream containing unreacted isoprene and alcohol is recycled to the etherification catalytic reactor through the overhead, Wherein the stream comprising the alkyl ether compound and the residue slurry of the etherification catalyst is discharged to the bottom of the column. 12. The method of claim 11,
And the third separation column has a lower temperature of 40 to 100 ° C. 12. The method of claim 11,
The stream containing the alkyl ether compound of isoprene and the residue slurry of the etherification catalyst flows into the fourth separation tower, and the stream containing the alkyl ether compound of isoprene is discharged into the column on the basis of the difference in boiling point. Is recycled to the etherification catalytic reactor through the bottom of the column. 14. The method of claim 13,
Wherein the fourth separation column has a lower temperature of 80 to 200 ° C. 10. The method of claim 9,
Wherein the alcohol is an alcohol having an alkyl group having 1 to 4 carbon atoms. 10. The method of claim 9,
The etherification catalyst includes at least one selected from the group consisting of cobalt (Co), rhodium (Rh), iridium (Ir), palladium (Pd), ruthenium (Ru), nickel (Ni) ≪ / RTI > 10. The method of claim 9,
Wherein the etherification catalyst is used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the isoprene. 10. The method of claim 9,
Wherein the step (e-2) is carried out in a de-etherification catalytic reactor which is a heterogeneous gas phase reactor at a temperature of 100 to 300 ° C, a pressure of 1 to 5 atm and a space velocity of 0.5 to 10 h ^-1 . 19. The method of claim 18,
In the step (e-2), the seventh stream is introduced into a flash drum, the inert gas is recycled to the deetherification catalytic reactor, and isobutylene, an unreacted isoprene alkyl ether compound and an alcohol Is discharged separately from the inert gas. 20. The method of claim 19,
The stream containing the isoprene, the unreacted isoprene alkyl ether compound, and the alcohol is introduced into the fifth separation column, the isoprene is recovered on the column in accordance with the difference in boiling point, and the unreacted isoprene alkyl ether compound and alcohol Is recycled to the de-etherification catalytic reactor via the bottom of the column. 21. The method of claim 20,
Wherein the fifth separation column has a lower temperature of 40 to 100 캜. 10. The method of claim 9,
Wherein the inert gas is a nitrogen gas. 10. The method of claim 9,
Wherein the deetherification catalyst is a compound represented by the following formula (1).
[Chemical Formula 1]

B, c, and d are integers, a / b is 1 to 10, and a / b is an integer of 1 to 10, and X is at least one element selected from the group consisting of zirconium (Zr) and titanium (Ti), Y is magnesium (Mg) c is an integer satisfying 5 to 30, and d is a valence of each element. 10. The method of claim 9,
Wherein the deetherification catalyst is used in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of the alkyl ether compound of isoprene. The method according to claim 1,
Wherein the step (f) is carried out in a reactor in the presence of a catalytic cracking catalyst at a temperature of 300 to 700 ° C and a space velocity of 1 to 20 h ^-1 . 26. The method of claim 25,
Wherein the catalytic cracking catalyst is a ZSM-5 catalyst prepared by using carbon powder or nanoporous particles having mesopore forming ability as a template material. 27. The method of claim 26,
Wherein said ZSM-5 catalyst is cationically substituted. 27. The method of claim 26,
Further comprising 0.01 to 10 parts by weight of phosphorus precursor based on 100 parts by weight of the ZSM-5 catalyst. 29. The method of claim 28,
Wherein the ZSM-5 catalyst further comprises a rare earth metal or alkali metal in an amount of 2 or less in atomic ratio to the phosphorus.

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