JP5050469B2 - Propylene production method - Google Patents

Description

  The present invention relates to a method for producing propylene from a raw material mixture containing an olefin having 4 or more carbon atoms and methanol and / or dimethyl ether.

As a method for producing olefins, steam cracking of naphtha and ethane (Non-patent Document 1) and fluid catalytic cracking of vacuum gas oil are generally performed, and an MTO process using methanol and / or dimethyl ether as a raw material is also used. Has attracted attention. Propylene is produced by a metathesis reaction using ethylene and 2-butene as raw materials, catalytic cracking of olefins having 4 or more carbon atoms, and further using olefins having 4 or more carbon atoms and oxygen-containing compounds such as methanol as raw materials. A method of manufacturing the stencil is also known (Patent Document 2).
HYDROCARBON PROCESSING, March 1999, 112 US Pat. No. 6,888,038

  Among the above-mentioned olefin production methods, the method using steam cracking is the mainstream worldwide. As a method of increasing the production of propylene in the existing steam cracking process, there is a method of increasing the amount of raw material supplied to the cracker. However, since this method produces more ethylene than propylene, it is not possible to increase the production of only propylene. It is possible and the production ratio of ethylene and propylene cannot be changed greatly. On the other hand, in a process for producing propylene using an olefin having 4 or more carbon atoms and an oxygen-containing compound such as methanol as raw materials (hereinafter referred to as “propylene production process”), it is possible to produce propylene at a high propylene / ethylene ratio. Therefore, by integrating the propylene production process with the steam cracking process, it becomes possible to greatly change the production ratio of ethylene and propylene, and it is possible to substantially increase only the production of propylene. Furthermore, since the propylene production process has less by-product of carbon dioxide than the steam cracking process, it is a method for increasing propylene production with a low environmental load.

  In addition, when the two processes of the propylene production process and the steam cracking process are integrated in this way, several advantages can be expected. One is the effective use of low-value fluids generated by each other's processes. For example, a portion of a hydrocarbon fluid having 4 or 5 carbon atoms produced in a steam cracking process is usually converted to a paraffin-rich fluid by hydrogenation and then returned to the cracker, but the fluid before hydrogenation is converted into a propylene production process. It can be used effectively as a raw material. On the other hand, a part of the fluid extracted in the propylene production process can be effectively used as a cracker raw material in the steam cracking process.

  Another advantage is the efficiency of the purification process. Although the composition of the cracker outlet fluid in the steam cracking process and the reactor outlet fluid in the propylene production process are greatly different, many other common compounds including ethylene and propylene are contained, so that the purification process can be shared. For example, if all the fluid generated in the propylene production process can be introduced into the purification process of the steam cracking process and purified, the capital investment in the propylene production process can be significantly reduced.

  However, not all of the fluid produced in the propylene production process can be purified in the steam cracking process. For example, the propylene production process is integrated into an existing steam cracking process that does not have a large margin in the processing capacity of the purification process. In many cases, it is difficult. Therefore, it has been desired to establish a method for remarkably reducing the utility cost and the capital investment cost under the condition that the propylene production process is integrated with the steam cracking process having a large margin in the processing capacity of the refining process.

  The present invention has been made to solve the above-mentioned problems, and a part of the reactor outlet fluid in the process of producing propylene by reacting an olefin having 4 or more carbon atoms with methanol and / or dimethyl ether is steamed. By introducing it into the cracking process, the objective is to provide a process with a low environmental impact that significantly changes the production balance of ethylene and propylene and significantly reduces the cost of utility and capital investment by improving the efficiency of the purification process. .

  In a propylene production process in which propylene is obtained by reacting an olefin having 4 or more carbon atoms with methanol and / or dimethyl ether, ethylene is produced as a low-boiling byproduct with 2 or less carbon atoms together with propylene. Low-boiling by-products having 2 or less carbon atoms include trace amounts of ethane, methane, and the like in addition to ethylene, and in some cases, hydrogen and carbon dioxide. Therefore, in order to obtain high-purity ethylene as a product, a process for removing those compounds is required. Although the amount of ethylene produced as a by-product is smaller than that of propylene, these separation steps require severe conditions such as extremely low temperature and high pressure, so that the capital investment becomes large. Therefore, it is preferable that the low-boiling by-product having 2 or less carbon atoms including ethylene is introduced into the purification step in the steam cracking process for purification. At this time, as the processing capacity of the purification process of the steam cracking process, if there is a margin for processing the ethylene produced in the propylene production process, it can be introduced as it is, and if the processing capacity is not enough, the steam cracking process What is necessary is just to reduce the amount of ethylene produced | generated by a steam cracking process by reducing a cracker raw material supply amount or using a heavy raw material as a cracker raw material. Even in that case, the total production amount of ethylene produced by the steam cracking process and the propylene production process is not reduced from the ethylene production amount of the steam cracking process before the integration of these processes. Therefore, it is possible to increase the production of propylene while omitting the ethylene purification step in the propylene production process and maintaining the ethylene production amount.

  As a result of intensive studies on a method for introducing ethylene generated in the propylene production process into the steam cracking process, the present inventors have found that propylene is contained in a specific ratio in the above-described fluid containing ethylene. It was found that it is possible to further reduce the capital investment and the utility cost.

  On the other hand, in a propylene production process in which an olefin having 4 or more carbon atoms and methanol and / or dimethyl ether are reacted, water close to the same mole as methanol or dimethyl ether as a raw material is by-produced. Normally, these waters are treated as waste water, but by selecting specific reaction conditions in a reactor for producing propylene, it is possible to reduce the concentration of C1-C5 acid contained in the water. And found that at least a portion of this by-product water can be introduced into the steam cracking process. By using this by-product water as a dilute steam source for crackers, it is possible to reduce the amount of water used in the steam cracking process, omit or reduce the size of wastewater treatment equipment, greatly increasing both utility costs and capital investment costs. Can be reduced.

  The present invention has been achieved based on such findings, and the gist thereof is as follows.

[1] In a method for producing propylene by contacting a mixture containing an olefin having 4 or more carbon atoms and methanol and / or dimethyl ether in a reactor in the presence of a catalyst, the following steps (1) and (2) , (3) and (4) comprising a process comprising the steps of:
The following step (2) condenses and removes moisture from the reactor outlet gas (A) by a cooling and compression step, and then, by distillation, a fluid (B) containing a hydrocarbon having 2 or less carbon atoms and propylene, and carbon It is separated into a fluid rich in hydrocarbons having a carbon number of 3 or more, and a fluid rich in hydrocarbons having a carbon number of 3 or more is separated by distillation into a fluid rich in propylene and a fluid rich in hydrocarbons having a carbon number of 4 or more ( Y) and separating
The propylene concentration in the following fluid (B) is in the range of 0.1 to 1.0 times by weight with respect to the concentration of ethylene contained in the fluid (B) .
Step (1): The olefin raw material having 4 or more carbon atoms, the hydrocarbon fluid (X) recycled from Step (3), and methanol and / or dimethyl ether are supplied to the reactor, and propylene, ethylene, Step of obtaining gas (reactor outlet gas) (A) containing butene, paraffin, aromatic compound and water Step (2): Reactor outlet gas (A) from step (1) is 2 or less carbon atoms Are separated into a hydrocarbon- and propylene-containing fluid (B), a propylene-rich fluid, a hydrocarbon-rich fluid (Y) having 4 or more carbon atoms, and a water-rich fluid (P). Step Step (3): Step of recycling part (X) of fluid (Y) to the reactor and extracting the remaining fluid from the process Step (4): Using fluid (B) for the steam cracking process Step of

[ 2 ] In a method for producing propylene by contacting a mixture containing an olefin having 4 or more carbon atoms and methanol and / or dimethyl ether in a reactor in the presence of a catalyst, the following steps (1) and (2) , (3) and (4) comprising a process comprising the steps of:
The following step (2) condenses and removes moisture from the reactor outlet gas (A) by a cooling and compression step, and then, by distillation, a fluid rich in hydrocarbons having 3 or less carbon atoms and carbonization having 4 or more carbon atoms. A fluid rich in hydrocarbons having a carbon number of 3 or less and a fluid rich in hydrocarbons and propylene having a carbon number of 2 or less by distillation (B) separated from a fluid rich in hydrogen (Y) and rich in propylene viewing including the step of separating the fluid's,
The propylene concentration in the following fluid (B) is in the range of 0.1 to 1.0 times by weight with respect to the concentration of ethylene contained in the fluid (B).
Step (1): The olefin raw material having 4 or more carbon atoms, the hydrocarbon fluid (X) recycled from Step (3), and methanol and / or dimethyl ether are supplied to the reactor, and propylene, ethylene, Step of obtaining gas (reactor outlet gas) (A) containing butene, paraffin, aromatic compound and water
Step (2): Reactor outlet gas (A) from step (1) above is a fluid (B) containing hydrocarbons and propylene having 2 or less carbon atoms, a fluid rich in propylene, and 4 or more carbon atoms. Separating into a hydrocarbon-rich fluid (Y) and a water-rich fluid (P)
Step (3): Recycling a part (X) of the fluid (Y) to the reactor and extracting the remaining fluid from the process
Step (4): Step of supplying the fluid (B) to the steam cracking process

[ 3 ] A method for producing propylene according to [1] or [2] , wherein the steam cracking process includes the following steps (5), (6), (7) and (8).
Step (5): Supply hydrocarbon to cracker raw material together with dilute steam to cracker and thermally decompose to gas containing ethylene, propylene, other olefins, paraffin, hydrogen, aromatic compound and water from cracker outlet (cracker) Step (6): After cooling the cracker outlet gas (C), the cracker outlet gas (C) is cooled and then introduced into the distillation tower to obtain fuel oil from the bottom of the tower, and the fuel oil is removed from the top of the tower. Step (7): Step (7): Gas (D) is introduced into the quench tower, and the fluid (Q) containing cracked gasoline and water is extracted from the bottom of the tower, and ethylene, propylene, other olefins, Step of obtaining gas (E) containing paraffin, hydrogen, and aromatic compound Step (8): The pressure of gas (E) is increased with a compressor, and an alkali washing tower Obtaining a hydrogen sulfide and / or carbon dioxide to remove the gas (F)

[ 4 ] In [ 3 ], the steam cracking process is a process including the following steps (9A), (10A), (11A) and (12A) following the step (8): Propylene production method.
Step (9A): Step of introducing gas (F) into the cryogenic separation step and separating it into hydrogen and other fluid (G) Step (10A): Introducing fluid (G) into the demethanizer tower, Step of separating methane and other fluid (H) Step (11A): Introducing fluid (H) into a deethanizer, a fluid rich in hydrocarbons having 2 carbon atoms, and carbonization having 3 or more carbon atoms Step of separating into fluid (I) rich in hydrogen Step (12A): Introducing fluid (I) into a depropanizer tower, into a fluid rich in hydrocarbons having 3 carbon atoms and hydrocarbons having 4 or more carbon atoms Separating into rich fluid

[ 5 ] In [ 3 ], the steam cracking process is a process including the following steps (9B), (10B), (11B) and (12B) following the step (8): Propylene production method.
Step (9B): Gas (F) is introduced into a depropanizer and separated into a hydrocarbon-rich fluid (J) having 3 or less carbon atoms and a hydrocarbon-rich fluid having 4 or more carbon atoms. Step Step (10B): Step of introducing fluid (J) into the cryogenic separation step and separating it into hydrogen and a fluid (K) rich in hydrocarbons having 1 to 3 carbon atoms Step (11B): Fluid (K ) Is introduced into the demethanizer tower and separated into methane and a hydrocarbon-rich fluid (L) having 2 to 3 carbon atoms. Step (12B): The fluid (L) is introduced into the deethanizer tower and carbon Separating into a fluid rich in hydrocarbons of number 2 and a fluid rich in hydrocarbons of carbon number 3

[ 6 ] In [ 3 ], the steam cracking process is a process including the following steps (9C), (10C), (11C) and (12C) following the step (8): Propylene production method.
Step (9C): The gas (F) is introduced into the depropanizer and separated into a hydrocarbon and hydrogen rich fluid (J) having 3 or less carbon atoms and a hydrocarbon rich fluid having 4 or more carbon atoms. Step Step (10C): The fluid (J) is introduced into the deethanizer and separated into a fluid rich in hydrocarbons having 1 to 2 carbon atoms and hydrogen (M) and a fluid rich in hydrocarbons having 3 carbon atoms. Step (11C): Step of introducing the fluid (M) into the cryogenic separation step and separating it into hydrogen and a hydrocarbon-rich fluid (N) having 1 to 2 carbon atoms Step (12C): Fluid ( N) is introduced into a demethanizer and separated into methane and a hydrocarbon-rich fluid containing 2 carbon atoms.

[ 7 ] In [ 3 ], the steam cracking process is a process including the following steps (9D), (10D), (11D) and (12D) following the step (8): Propylene production method.
Step (9D): Gas (F) is introduced into the deethanizer, and a hydrocarbon and hydrogen rich fluid (O) having 2 or less carbon atoms and a hydrocarbon (I) rich in hydrocarbons having 3 or more carbon atoms and Step (10D): Step of introducing fluid (O) into the cryogenic separation step and separating it into hydrogen and a hydrocarbon-rich fluid (N) having 1 to 2 carbon atoms Step (11D): Step of introducing fluid (N) into the demethanizer tower and separating it into methane and a fluid rich in hydrocarbons having 2 carbon atoms Step (12D): introducing fluid (I) into the depropanizer tower and adding 3 carbon atoms Separation into a hydrocarbon-rich fluid and a hydrocarbon-rich fluid with 4 or more carbon atoms

[ 8 ] In any one of [ 3 ] to [ 7 ], the fluid (B) is supplied from a cracker outlet in the step (6) to any location between the alkali cleaning towers in the step (8). Propylene production method characterized by the above.

[ 9 ] In [ 8 ], the fluid (B) is supplied to any location between the top of the quench tower in the step (7) and the alkali washing tower in the step (8). Propylene production method.

[ 10 ] In [ 4 ], the fluid (B) is supplied to any location between the top of the alkali washing tower in the step (8) and the demethanizer tower in the step (10A). Propylene production method.

[ 11 ] In [ 5 ], the fluid (B) is supplied from the top of the alkali cleaning tower in the step (8) to any position between the demethanizer tower in the step (11B). Propylene production method.

[ 12 ] In [ 6 ], the fluid (B) is supplied to any position between the top of the alkali washing tower in the step (8) and the deethanizer in the step (10C). Propylene production method.

[ 13 ] In [ 7 ], the fluid (B) is supplied to any position between the top of the alkali washing tower in the step (8) and the deethanizer tower in the step (9D). Propylene production method.

  According to the present invention, the production balance of ethylene and propylene is obtained by introducing a part of the product in the process of producing propylene by reacting an olefin having 4 or more carbon atoms with methanol and / or dimethyl ether into the steam cracking process. In addition, it is possible to provide a process with a small environmental load that significantly reduces utility costs and capital investment costs.

  Below, the typical aspect for implementing this invention is demonstrated concretely, However, This invention is not limited to the following aspects, unless the summary is exceeded.

The present invention includes four steps (1), (2), (3) and (4) as described above, or (IE), (2E), (3E) and (4E). As long as the purpose of solving the above problem is followed, the existence of other processes is not excluded, other processes may exist before and after the four processes, and other processes exist between each process. You may do it.
Similarly, a process including steps (5), (6), (7), and (8), and further including steps (9A), (10A), (11A), and (12A) following step (8). Process, process including steps (9B), (10B), (11B) and (12B), process including steps (9C), (10C), (11C) and (12C), steps (9D), (10D) , (11D) and a process including (12D), and a process including steps (5E), (6E), (7E), (8E), (9E) and (10E) also solve the problems of the present invention. As long as the purpose is followed, the presence of other processes is not excluded, and other processes may exist before and after these processes, and other processes may exist between the processes.

  In the present invention, “rich” means that the purity of the target product is 90 mol% or more, preferably 95 mol% or more, more preferably 99 mol% or more. For example, the “fluid rich in hydrocarbons having 4 or more carbon atoms (Y)” means “hydrocarbons having 4 or more carbon atoms” in 90 mol% or more, preferably 95 mol% or more, more preferably 99 mol% or more. Fluid containing.

[catalyst]
First, the catalyst used in the present invention will be described.
The catalyst used in the reaction according to the present invention is not particularly limited as long as it is a solid having a Bronsted acid point, and a conventionally known catalyst is used. For example, clay minerals such as kaolin; clay minerals and the like Solid acid catalysts such as those obtained by impregnating and supporting an acid such as sulfuric acid and phosphoric acid on a support; acidic ion exchange resins; zeolites; aluminum phosphates; and mesoporous silica alumina such as Al-MCM41.

  Among these solid acid catalysts, those having a molecular sieving effect are preferable, and those having a low acid strength are preferable.

Among the solid acid catalysts, the structures of zeolites and aluminum phosphates having a molecular sieving effect are represented by codes defined by the International Zeolite Association (IZA), for example, AEI, AET, AEL, AFI, AFO, AFS, AST, ATN, BEA, CAN, CHA, EMT, ERI, EUO, FAU, FER, LEV, LTL, MAZ, MEL, MFI, MOR, MTT, MTW, MWW, OFF, PAU, RHO, STT, TON, etc. It is done. Among them, a catalyst having a catalyst framework density of 18.0 T / nm ³ or less is preferable, and as such, preferably MFI, MEL, MOR, MWW, FAU, BEA, CHA, more preferably , MFI, MEL, MOR, MWW, CHA, particularly preferably MFI, MEL, MWW, CHA.
Here, the framework density (unit: T / nm ³ ) is the number of T atoms (atoms other than oxygen among the atoms constituting the skeleton of the zeolite) present per unit volume (1 nm ³ ) of the zeolite. This value is determined by the structure of the zeolite.

More preferably, the solid acid catalyst has micropores having a pore diameter of 0.3 to 0.9 nm, a BET specific surface area of 200 to 700 m ² / g, and a pore volume of 0.1 to 0.00. Crystalline aluminosilicates, metallosilicates, crystalline aluminum phosphates and the like that are 5 g / cc are preferred. In addition, the pore diameter mentioned here indicates a crystallographic channel diameter (Crystallographic free diameter of the channels) defined by International Zeolite Association (IZA). When the diameter is a pore and the shape of the pore is an ellipse, the short diameter is indicated.

Among aluminosilicates, those having a SiO ₂ / Al ₂ O ₃ molar ratio of 10 or more are preferred. If the SiO ₂ / Al ₂ O ₃ molar ratio is too low, the durability of the catalyst is lowered, which is not preferable. The upper limit of the molar ratio of SiO ₂ / Al ₂ O ₃ is usually 10,000 or less. If the molar ratio of SiO ₂ / Al ₂ O ₃ is too high, the catalytic activity is lowered, which is not preferable. The molar ratio can be determined by a conventional method such as fluorescent X-ray or chemical analysis.
The aluminum content in the catalyst can be controlled by the amount of raw material charged during catalyst preparation, and Al can be reduced by steaming after the preparation. Further, a part of Al may be replaced with other elements such as boron and gallium, and it is particularly preferable to substitute with boron.

  These catalysts may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  In the present invention, a substance or binder that is inert to the reaction may be used for granulation and molding, or these may be mixed for use in the reaction. Examples of the substance or binder inert to the reaction include alumina or alumina sol, silica, silica gel, quartz, and a mixture thereof.

  The catalyst composition described above is a composition of only a catalytically active component that does not contain a substance inactive to these reactions, a binder, and the like. Thus, when the catalyst according to the present invention includes a substance or binder inactive to these reactions, the catalyst active component and the substance inactive to these reactions are combined with the catalyst. In the case where a substance inactive to these reactions, a binder, or the like is not included, it is referred to as a catalyst with only catalytically active components.

  The particle diameter of the catalytically active component used in the present invention varies depending on the conditions during synthesis, but is usually 0.01 μm to 500 μm as the average particle diameter. If the particle size of the catalyst is too large, the surface area showing catalytic activity will be small, and if it is too small, the handleability will be inferior, which is not preferable in either case. This average particle diameter can be determined by SEM observation or the like.

The method for preparing the catalyst used in the present invention is not particularly limited, and the catalyst can be prepared by a known method generally called hydrothermal synthesis. It is also possible to change the composition after the hydrothermal synthesis by modification such as ion exchange, dealumination treatment, impregnation or loading.
The catalyst used in the present invention may be any catalyst as long as it has the above physical properties or composition when subjected to the reaction, and may be prepared by any method.

[Reaction raw materials]
Next, the olefin having 4 or more carbon atoms, methanol, and dimethyl ether used as reaction raw materials in the present invention will be described.

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

Among these, when an olefin raw material containing paraffins having 4 or more carbon atoms is used, the reaction temperature can be easily controlled because paraffin serves as a dilution gas, and paraffin-containing raw materials are available at low cost. It is preferable because there are many cases. More preferred is an olefin raw material containing normal butane and / or isobutane.
These preferable raw materials include the above-mentioned BB fraction, C4 raffinate-1 and C4 raffinate-2. Since the BB fraction contains a large amount of butadiene, it is preferable to use a fluid that is brought into contact with a hydrogenation catalyst to lower the butadiene concentration as a raw material.

<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 of the propylene production process: steps (1), (1E)]
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 4 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, it selects from a continuous type fixed bed reactor and a fluidized bed reactor. A fixed bed reactor is preferred.

  In addition, when packing the above-mentioned catalyst in a fixed bed reactor, in order to suppress the temperature distribution of the catalyst layer to be small, particulates inert to the reaction such as quartz sand, alumina, silica, silica-alumina, etc. And may be mixed and 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 reactor may be composed of two or more reaction parts connected in series. In this case, one reactor may be divided into a plurality of reaction chambers, or two or more reactors may be connected in series.
When two or more reactors are connected in series as described above, a heat exchanger may be disposed between the reactors for the purpose of removing heat generated by the reaction.
Further, the reaction substrate (reaction raw material) may be divided and supplied for the purpose of dispersing heat generation. Preferably, methanol and / or dimethyl ether are divided and supplied to the first-stage reaction section (reactor or reaction chamber) and the second-stage and subsequent reaction sections (reactor or reaction chamber).

Under the reaction conditions used in the present invention, the catalyst has little coking and the rate of catalyst deterioration is slow, but when performing continuous operation for more than one year, 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 in parallel 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 a method of regenerating the catalyst deteriorated by coking by treating it with nitrogen gas or water vapor containing oxygen. The regeneration operation in the fixed bed reactor is preferably performed by removing volatile organic compounds adhering to the catalyst with nitrogen gas, then burning and removing the coke with nitrogen gas containing a low concentration of oxygen, and then nitrogen gas. The method of removing the molecular oxygen contained in a catalyst layer by processing by is mentioned.

<Concentration ratio of olefin and methanol and / or dimethyl ether supplied to the reactor>
In the present invention, the amount of the olefin having 4 or more carbon atoms supplied to the reactor is 0.2 in terms of a molar ratio with respect to the sum of the number of moles of methanol supplied to the reactor and twice the number of moles of dimethyl ether. Above, preferably 0.5 or more, 10 or less, preferably 5 or less.
That is, when the supply molar amount of olefins having 4 or more carbon atoms is Mc4, the supply molar amount of methanol is Mm, and the supply molar amount of dimethyl ether is Mdm, Mc4 is 0.2 to 10 times (Mm + 2Mdm), preferably 0. .5 to 5 times.
If this supply concentration ratio is too low or too high, the reaction will be slow, which is not preferable. In particular, if this supply concentration ratio is too low, the consumption of olefin as a raw material will decrease, which is not preferable.

Here, the supply concentration ratio can be known by quantifying the composition of each fluid supplied to the reactor or the fluid after mixing by a general analytical method such as gas chromatography.
When the olefin having 4 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 supplied to the reactor>
In the present invention, the total concentration (substrate concentration) of the olefin having 4 or more carbon atoms, methanol and dimethyl ether in all the feeds supplied to the reactor is preferably 20% by volume to 80% by volume, more preferably 30% by volume. % To 70% by volume.
Here, the substrate concentration can be known by quantifying the composition of each fluid supplied to the reactor or the fluid after mixing by a general analytical technique such as gas chromatography.

If the substrate concentration is too high, aromatic compounds and paraffins are prominently produced and the propylene selectivity tends to decrease. On the other hand, if the substrate concentration is too low, the reaction rate becomes slow, so a large amount of catalyst is required, and further, the product purification cost and the construction cost of the reaction equipment increase, which is not economical.
In the present invention, the reaction substrate is diluted with a diluent gas described below so as to obtain such a substrate concentration. In this case, the method for controlling the substrate concentration includes a method for controlling the flow rate of the fluid extracted from the process. That is, by changing the flow rate of the fluid withdrawn from the process, it is possible to change the flow rate of the dilution gas recycled to the reactor and change the substrate concentration.

<Concentration of impurities in the gas supplied to the reactor>
In the present invention, butadiene may be contained in the olefin raw material having 4 or more carbon atoms and / or in the hydrocarbon-containing fluid to be recycled, which will be described later. The concentration is preferably 2.0% by volume or less. A high concentration of butadiene in the raw material is not preferable because deterioration due to coking of the catalyst is accelerated.

Here, the butadiene concentration can be known by quantifying the composition of each fluid supplied to the reactor or the fluid after mixing by a general analytical method such as gas chromatography.
Examples of the method for reducing the concentration of butadiene in the raw material include a partial hydrogenation method in which the fluid is brought into contact with a hydrogenation catalyst and converted into olefins.

  In addition, the hydrocarbon-containing fluid described later recycled to the reactor may contain aromatic compounds, but the total amount of aromatic compounds contained in all raw materials supplied to the reactor is It is preferable that the molar ratio is less than 0.05 with respect to the total amount of olefins having 4 or more carbon atoms contained in all the raw materials supplied to. When the concentration of the aromatic compound in the raw material is high, the aromatic compound reacts with methanol and / or dimethyl ether in the reactor, which consumes methanol and / or dimethyl ether more than necessary.

Here, the ratio of the total amount of the aromatic compound and the total amount of the olefin having 4 or more carbon atoms is determined by general analysis such as gas chromatography of the composition of each fluid supplied to the reactor or the fluid after mixing. It can be known by quantifying with a technique.
Examples of the method for reducing the concentration of the aromatic compound in the raw material include a separation method by distillation.

<Dilution gas>
In the reactor, in addition to olefins having 4 or more carbon atoms and methanol and / or dimethyl ether, paraffins, aromatics, water vapor, carbon dioxide, carbon monoxide, nitrogen, argon, helium, and mixtures thereof are used. A gas inert to the reaction can be present. Of these dilution gases, paraffins and aromatics may react slightly depending on the reaction conditions, but are defined as dilution gases because the reaction amount is small.
As such a dilution gas, impurities contained in the reaction raw material may be used as they are, or a separately prepared dilution gas may be mixed with the reaction raw material.
Further, the dilution gas 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 the olefin having 4 or more carbon atoms, which is a reaction raw material per weight of the catalyst (catalytic active component). Here, the weight of the catalyst is an amount used for granulation / molding of the catalyst. This is the weight of the catalytically active component that does not contain the active component or binder. The flow rate is a flow rate (weight / hour) of an olefin having 4 or more carbon atoms.

The space velocity is preferably between 0.1 Hr ⁻¹ and 500 Hr ⁻¹ , and more preferably between 1.0 Hr ⁻¹ and 100 Hr ⁻¹ . 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 as the gas temperature at the reactor inlet, and 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.

<Consumption of raw materials by reaction>
The sum of the molar flow rate of methanol fed to the reactor and twice the molar flow rate of dimethyl ether is preferably less than 1%. More preferably, it is less than 0.1%.
If the consumption of methanol and dimethyl ether in the reactor is small and the amount of methanol and dimethyl ether at the reactor outlet is too large, it becomes difficult to purify the product olefin.
As a method for increasing the consumption of methanol and dimethyl ether, a method of increasing the reaction temperature or decreasing the space velocity can be mentioned.

In the present invention, the molar flow rate of the olefin having 4 or more carbon atoms at the outlet of the reactor is 20% or more and less than 70% with respect to the molar flow rate of the olefin having 4 or more carbon atoms supplied to the reactor. This molar flow rate is preferably 25% or more and less than 60%. If the consumption of olefins having 4 or more carbon atoms in the reactor is too small, the amount of unreacted olefin increases, and the flow rate of the fluid recycled to the reactor becomes too large. On the other hand, if the amount of consumption is too large, undesirable compounds such as paraffin and aromatic compounds are by-produced and the yield of propylene is lowered, which is not preferable.
Examples of the method for adjusting the consumption of olefins having 4 or more carbon atoms in the reactor include a method of appropriately setting the reaction temperature, space velocity, and the like.

  Here, the flow rate of methanol, dimethyl ether and olefin having 4 or more carbon atoms supplied to the reactor is determined by a general analytical method such as gas chromatography for the composition of each fluid supplied to the reactor or the fluid after mixing. The flow rate of each fluid can be determined by measuring the flow rate of methanol and dimethyl ether at the reactor outlet and the flow rate of olefins having 4 or more carbon atoms. It can be known by quantifying with a technique and measuring or calculating the flow rate of the reactor outlet fluid.

<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 4 or more carbon atoms. Depending on the reaction conditions, methanol and / or dimethyl ether may be included, but it is preferable to carry out the reaction under such reaction conditions that methanol and / or dimethyl ether does not remain. Thereby, separation of the reaction product and the unreacted raw material becomes easy.
By-products include ethylene, olefins having 4 or more carbon atoms, paraffins, aromatic compounds, and water.

[Separation process of propylene production process]
In the present invention, the reactor outlet gas (A) from step (1) is converted into a fluid (B) containing a hydrocarbon having 2 or less carbon atoms and propylene, a fluid rich in propylene, and a carbonization having 4 or more carbon atoms. A fluid rich in hydrogen (hereinafter sometimes referred to as “hydrocarbon fluid having 4 or more carbon atoms”) (Y) and a fluid rich in water (P) (step (2)) are separated into a fluid ( A portion (X) of Y) is recycled to the reactor, the remaining fluid is withdrawn from the process (step (3)), and fluid (B) is fed to the steam cracking process (step (4)). Alternatively, the reactor outlet gas (A) is separated into a hydrocarbon-rich fluid (W) and a water-rich fluid (P) (step (2E)), and the hydrocarbon-rich fluid (W) Part (Z) is recycled to the reactor, the remaining fluid is withdrawn from the process (step (3E)), fluid (P) is fed to the steam cracking process and used as dilute steam for the cracker (step (4E)). )).

  The steps (2) to (4) to (2A) to (4E) will be described below with reference to FIG.

  In FIG. 1, 11 is a reactor and 12 is a separation and purification process. 101-110 show piping, respectively.

The olefin raw material having 4 or more carbon atoms, the hydrocarbon fluid (X) having 4 or more carbon atoms from the separation and purification step 12, methanol and / or dimethyl ether are respectively supplied to the reactor 11 via the pipes 101, 102 and 103 and the pipe 104. The The olefin raw material having 4 or more carbon atoms supplied to the reactor 11 may contain paraffins having 4 or more carbon atoms, such as normal butane and isobutane. Further, the raw material fluid supplied to the reactor 11 through the pipe 104 may contain butadiene or an aromatic compound. As described above, the butadiene concentration in the raw material fluid is usually 2.0% by volume or less, and the total amount of aromatic compounds is moles relative to the total amount of olefins having 4 or more carbon atoms contained in the raw material fluid of the pipe 104. The ratio is usually preferably less than 0.05. In addition, although the raw material fluid means the sum total of the fluid supplied through piping 101,102, and 103, these do not necessarily need to merge before entering into the reactor 11, It supplies to the reactor 11 separately. May be. The raw material gas supplied to the reactor 11 reacts in contact with the catalyst in the reactor 11 to obtain a reactor outlet gas (A) containing propylene, other olefins, paraffins, aromatic compounds and water. .
The reactor outlet gas (A) is fed from a pipe 105 to a general separation and purification step (12) such as cooling, compression and distillation, and a fluid (B) containing a hydrocarbon having 2 or less carbon atoms and propylene. , Separated into a fluid rich in propylene, a fluid rich in hydrocarbons having 4 or more carbon atoms (Y, W), and a fluid rich in water (P) and taken out from the pipes 106, 107, 108, 110, respectively. It is.

  A part of the hydrocarbon-rich fluid (Y, W) having 4 or more carbon atoms is recycled to the reactor 11 through the pipe 102, and the remaining fluid is extracted from the process. Also, the water-rich fluid (P) is fed to the steam cracking process and utilized as cracker dilution steam.

  As a first aspect of a general separation step in the separation / purification step 12, the reactor outlet gas (A) from the pipe 105 is condensed and removed by cooling and compression steps, and then carbonized by carbonization of 2 or less by distillation. Separation into a fluid (B) containing hydrogen and propylene and a fluid rich in hydrocarbons having 3 or more carbon atoms, followed by distilling the fluid rich in hydrocarbons having 3 or more carbon atoms into a fluid rich in propylene And a method including a step of separating the hydrocarbon-rich fluid (Y) having 4 or more carbon atoms.

  Further, as a second aspect, after the reactor outlet gas (A) from the pipe 105 is condensed and removed by the cooling and compression process, a fluid rich in hydrocarbons having 3 or less carbon atoms and carbon are obtained by distillation. A fluid (B) containing hydrocarbons and propylene having 2 or less carbon atoms by distilling a fluid rich in hydrocarbons having 3 or less carbon atoms by separation into a fluid (Y) rich in hydrocarbons having 4 or more hydrocarbons And a method comprising a step of separating into a fluid rich in propylene.

In the first and second aspects described above, it is preferable to perform treatments such as quenching, alkali washing, and dehydration as necessary. When the oxygen-containing compound is contained in the reactor outlet gas, at least a part of the oxygen-containing compound is removed by the quenching process. When the reactor outlet gas contains an acidic gas such as carbon dioxide, at least a part of the acidic gas is removed by alkali cleaning.
Separation of water is possible mainly by condensation through compression and cooling. The remaining water is preferably removed with an adsorbent such as molecular sieve.

  At least a part of the fluid (B) containing a hydrocarbon having 2 or less carbon atoms and propylene obtained in the first aspect and the second aspect is supplied to any place in a steam cracking process described later, and steam Ethylene and propylene are purified in the cracking process. This can significantly reduce the capital investment for the propylene production process.

  In addition, the density | concentration of the propylene contained in the fluid (B) containing a C2-C2 hydrocarbon and propylene obtained by the 1st aspect and the 2nd aspect is the density | concentration of ethylene contained in the fluid (B). The weight ratio is preferably 0.1 to 1.0 times. As a result, the number of stages of the distillation column for obtaining the same fluid (B) in the propylene production process can be reduced and the capital investment cost can be reduced, and the utility cost in the distillation column can also be reduced.

In addition, it is preferable that the fluid rich in propylene is further purified in a separation step such as distillation to obtain high-purity propylene.
The purity of propylene is 95% or more, preferably 99% or more. More preferably, it is 99.9% or more.

  Propylene produced in this way can be used for all of the generally produced propylene derivatives, for example, for the production of acrylonitrile by ammoxidation, for the production of acrolein, acrylic acid and acrylate by selective oxidation, and for normal by oxo reaction. The present invention can be applied to the production of oxo alcohols such as butyl alcohol and 2-ethylhexanol, the production of polypropylene by polymerization of propylene, and the production of propylene oxide and propylene glycol by the selective oxidation of propylene. Further, acetone can be produced by Wacker reaction, and methyl isobutyl ketone can be produced from acetone. Acetone cyanohydrin can also be produced from acetone, which is ultimately converted to methyl methacrylate. Isopropyl alcohol can also be produced by propylene hydration. In addition, phenol, bisphenol A, and polycarbonate resin can be produced using a cumene produced by alkylating benzene as a raw material.

  On the other hand, at least a part of the water (fluid (P)) separated and removed in the first aspect and the second aspect is supplied to any place in the steam cracking process described later, and the steam source of the dilute water vapor of the cracker Used as As a result, wastewater treatment equipment in the propylene production process can be omitted or reduced in scale, and equipment investment can be significantly reduced.

  Part of the hydrocarbon fluids (Y) and (W) having 4 or more carbon atoms taken out from the pipe 108 are recycled to the reactor 10 via the pipe 102, and the remaining fluid is extracted from the propylene production process via the pipe 109. . Here, being extracted from the propylene production process means that it is not recycled to the reactor 10 of the process, and may be supplied directly to other processes through piping, or once stored in a tank through piping. Things may be supplied to other processes. Moreover, you may use as a fuel, without supplying to another process.

  The hydrocarbon fluids (Y) and (W) having 4 or more carbon atoms from the separation and purification step 12 are recycled to the reactor (11) without being introduced into the separation step such as distillation. Although it may be divided into fluids to be extracted to the outside, at least a part of the hydrocarbon fluids (Y) and (W) having 4 or more carbon atoms are further introduced into a separation process such as distillation, and the fluids to be recycled are extracted. It is preferable to adjust the composition of the fluid to be discharged to a desired range.

  It is particularly preferred that the fluid whose composition is adjusted as necessary and withdrawn from the pipe 109 is fed to the steam cracking process and mixed with the cracker feedstock and / or cracked gasoline. This makes it possible to effectively use the fluid extracted from the propylene production process. The cracked gasoline here means a fluid rich in hydrocarbons having 5 or more carbon atoms, preferably a fluid mainly containing paraffins, olefins, dienes and aromatic compounds having 5 to 10 carbon atoms. .

  Moreover, an active ingredient can be collect | recovered from cracked gasoline as needed. As an active ingredient, aromatic compounds, such as C5 hydrocarbon and benzene, toluene, xylene, are mentioned, for example.

  As a fluid mixed with the raw material of said cracker, it is preferable that the sum total of an aromatic compound density | concentration is less than 5.0 volume%, More preferably, it is less than 3.0 volume%. When the aromatic compound concentration is high, there is a large amount of carbon deposition when supplied to the cracker, and the ethylene yield tends to decrease, which is not preferable. In addition, when a fluid having a high olefin concentration is supplied to the cracker, carbon deposition is likely to occur in the cracker. Therefore, it is preferable to contact the hydrogenation catalyst as necessary to supply a fluid with an increased paraffin concentration to the cracker.

  As a fluid mixed with the cracked gasoline, the hydrocarbon having 4 carbon atoms is preferably less than 5% by weight, and more preferably less than 2% by weight. If the hydrocarbon having 4 carbon atoms is contained, it is not preferable because the hydrocarbon having 4 carbon atoms is mixed in the hydrocarbon fluid having 5 carbon atoms recovered from cracked gasoline.

  Further, the concentration of propylene in the fluid (B) supplied to the steam cracking process may be in the range of 0.1 to 1.0 times by weight with respect to the concentration of ethylene contained in the fluid (B). preferable. Even if there is more propylene and less ethylene than this range, there is an inconvenience that even if there is less propylene and more ethylene, the total energy required for distillation in the steam cracking process and the propylene production process becomes large and the utility cost increases. .

[Steam cracking process]
Hereinafter, the steam cracking process will be described with reference to FIGS.
<Steps from cracker to alkali cleaning tower (Description of steps (5) to (8) and steps (5E) to (10E))>
First, the process from a cracker to an alkali washing tower is demonstrated using FIG.

  In FIG. 2, 21 is a cracker, 22 is a distillation column, 23 is a quench column, 24 is a compressor, 25 is an alkali washing column, 26 is an oil / water separator, 27 is a process water stripper, 28 is a steam generator, 201 Reference numerals 214 denote pipes.

The cracker raw material is introduced into the cracker (thermal cracking furnace) 21 together with the diluted steam from the pipe 202 from the pipe 201, and is thermally decomposed at a temperature of about 760 to 900 ° C. to produce a pyrolysis product having an average molecular weight lower than that of the cracker raw material. can get.
Here, the cracker raw material is a hydrocarbon fluid supplied to the thermal cracking furnace, and ethane, butane, naphtha, kerosene, light oil, etc. are usually used. Diluted steam is steam that is added to dilute the cracker raw material, thereby increasing the yield of ethylene and propylene and suppressing carbon deposition in the thermal cracking furnace.

  The cracking product of cracker 21 is a gas (C) containing ethylene, propylene, other olefins, paraffin, hydrogen, aromatic compounds and water, and this cracker outlet gas (C) is a heat exchanger or fluid (C ) Is cooled by contact mixing with a lower temperature fluid, and then supplied to the distillation column 22 through the pipe 203. High boiling fuel oil is extracted from the bottom of the tower through the pipe 205, and fuel oil is supplied from the top of the tower. The removed gas (D) is obtained. Here, the fuel oil means a hydrocarbon having a large carbon number contained in the cracker outlet gas (C), and is usually a fluid rich in hydrocarbon having 11 or more carbon atoms. The gas (D) is supplied to the quench tower 23 through the pipe 204 and rapidly cooled, and includes gas (E) containing ethylene, propylene, other olefins, paraffin, hydrogen, and an aromatic compound, and water derived from diluted water vapor. The fluid (Q) is separated, the gas (E) is taken out through the pipe 206, the fluid (Q) is fed from the pipe 207 to the oil / water separator 26, and the water phase (R) and mainly having 6 or more carbon atoms. Separated into an oil phase containing hydrocarbons. The oil phase is taken out from the pipe 211. The aqueous phase (R) is supplied to the process water stripper 27 via the pipe 212, strips volatile hydrocarbons and takes it out from the tower top via the pipe 213, and removes at least a part of the volatile hydrocarbons from the tower bottom. Water (S) is obtained. Water (S) is taken out from the pipe 214, supplied to the steam generator 28, and reused as diluted steam supplied to the cracker 21. However, since the separated water contains non-volatile hydrocarbons, in order to remove the non-volatile hydrocarbons, a part of the water (S) is taken out of the system from a pipe not shown and discarded, New water is replenished as it is discarded.

  On the other hand, the gas (E) obtained in the quench tower 23 is pressurized by the compressor 24 via the pipe 206 and then supplied to the alkali cleaning tower 25 via the pipe 208 to remove sulfur compounds and / or carbon dioxide. Gas (F) is obtained. This gas (F) is taken out from the pipe 209, and the tower bottom component is discharged out of the system through the pipe 210.

<Process after alkali cleaning tower>
As the steps after the alkali washing tower, several modes can be adopted depending on the arrangement of the distillation tower. A typical aspect will be described with reference to FIGS.
3 to 6, 31 is a compressor, 32 is a gas-liquid separator, 33 is a cryogenic separation step, 34 is a demethanizer tower, 35 is a deethanizer tower, 36 is a depropanizer tower, and 37 is a condensate stripper. , 301 to 314 are pipes, respectively.

  As a first aspect, a front-end demethanization process is applied in which methane in the hydrocarbon fluid is first separated. A 1st aspect is demonstrated using FIG.

  The gas (F) from which the sulfur compound and / or carbon dioxide has been removed in the alkali cleaning tower 25 of FIG. 2 is introduced into the compressor 31 through the pipe 301 and further compressed, and then the cryogenic separation step 33 through the pipe 302. Is separated into a fluid rich in hydrogen and a fluid (G) other than that, and a fluid rich in hydrogen is taken out from the pipe 303. The fluid (G) from which hydrogen has been removed is introduced into the demethanizer 34 through the pipe 304 and separated into a methane-rich fluid and another fluid (H), which respectively passes through the pipe 305 and the pipe 306. It is taken out from the top and bottom of the tower. Here, the upper part of the tower may be the top of the tower, but may be an upper part from the middle as the number of stages of the distillation tower of the demethanizer 34. The number of stages of the distillation column of the demethanizer 34 indicates the actual number of stages in the case of a tray tower, and the number of theoretical stages in the case of a packed tower.

  The hydrocarbon fluid (H) separated by the demethanizer 34 is introduced into the deethanizer 35 through the pipe 306, and a fluid rich in hydrocarbons having 2 carbon atoms from the top of the tower, and having 3 or more carbon atoms from the bottom of the tower. The hydrocarbon-rich fluid (I) is obtained from the pipe 308 and the pipe 309, respectively. The hydrocarbon-rich fluid (I) having 3 or more carbon atoms is introduced into the depropanizer tower 36 through the pipe 309 to obtain a fluid rich in hydrocarbons having 3 carbon atoms from the top of the tower and carbon from the tower bottom. A hydrocarbon fluid of several 4 or more is obtained, and discharged from the system through the pipe 310 and the pipe 311 respectively.

  When a part of the fluid is condensed in the compressor 31, a part of the fluid is separated from the pipe 314 into a gas phase and a liquid phase by the gas-liquid separator 32, and the gas phase is separated from the pipe 315 to the pipe 302. The liquid phase may be returned to the condensate stripper 37 from the pipe 316. In this case, hydrocarbons having 2 or less carbon atoms contained in the liquid phase are recovered from the top of the condensate stripper 37 and returned to the front of the compressor 31 through the pipe 312 and at least 3 carbon atoms obtained from the bottom of the column. The hydrocarbon fluid is preferably supplied to the depropanizer 36 via a pipe 313.

  As the second and third embodiments, a front-end depropanization process for first separating hydrocarbons having 4 or more carbon atoms is applied. First, a 2nd aspect is demonstrated using FIG.

  The gas (F) from which the sulfur compound and / or carbon dioxide has been removed in the alkali cleaning tower 25 of FIG. 2 is introduced into the depropanizer tower 36 through the pipe 317 and converted into hydrocarbons and hydrogen having 3 or less carbon atoms from the top of the tower. A rich fluid (J) is obtained, and a fluid rich in hydrocarbons having 4 or more carbon atoms is obtained from the bottom of the tower, and is extracted from a pipe 318 and a pipe 319, respectively. The fluid (J) is supplied to the compressor 31 through the pipe 318 and compressed, and then supplied to the cryogenic separation step 33 through the pipe 320, and the fluid rich in hydrogen is removed from the pipe 321. The fluid (K) from which hydrogen has been removed is introduced into the demethanizer tower 34 via the pipe 322, and a fluid rich in methane is obtained from the top of the tower, and a hydrocarbon rich in carbon atoms of 2 to 3 is obtained from the bottom of the tower. A fluid (L) is obtained and taken out through a pipe 323 and a pipe 324, respectively. The fluid (L) is introduced into the deethanizer 35 through the pipe 324 to obtain a fluid rich in hydrocarbons having 2 carbon atoms from the top of the tower, and a fluid rich in hydrocarbons having 3 carbon atoms from the bottom of the tower. These are taken out through a pipe 325 and a pipe 326, respectively.

Next, a 3rd aspect is demonstrated using FIG.
The gas (F) from which the sulfur compound and / or carbon dioxide has been removed in the alkali cleaning tower 25 of FIG. 2 is introduced into the depropanizer tower 36 through the pipe 327 and converted into hydrocarbons and hydrogen having 3 or less carbon atoms from the top of the tower. A rich fluid (J) is obtained, and a fluid rich in hydrocarbons having 4 or more carbon atoms is obtained from the bottom of the tower, and taken out from the pipe 328 and the pipe 329, respectively. The fluid (J) is introduced into the deethanizer 35 through the pipe 328 to obtain a fluid (M) rich in hydrocarbons having 2 or less carbon atoms from the top of the tower, and rich in hydrocarbons having 3 carbon atoms from the bottom of the tower. A fluid is obtained and taken out from the pipe 330 and the pipe 331, respectively. The hydrocarbon-rich fluid (M) having 2 or less carbon atoms is supplied to the compressor 31 through the pipe 330 and compressed, and then supplied to the cryogenic separation step 33 through the pipe 332, and the hydrogen-rich fluid is supplied to the pipe 333. Remove more. The fluid (N) from which hydrogen has been removed is introduced into the demethanizer tower 34 through the pipe 334 to obtain a methane-rich fluid from the top of the tower, and a hydrocarbon-rich fluid having 2 carbon atoms from the bottom of the tower. Obtained from the pipe 335 and the pipe 336, respectively.

  As a fourth aspect, a front-end deethanization process is applied in which a fluid rich in hydrocarbons having 2 or less carbon atoms and a fluid rich in hydrocarbons having 3 or more carbon atoms are first separated. A 4th aspect is demonstrated using FIG.

  The gas (F) from which sulfur compounds and / or carbon dioxide has been removed in the alkali cleaning tower 25 of FIG. 2 is introduced into the deethanizer tower 35 through the pipe 337, and converted into hydrocarbons and hydrogen having 2 or less carbon atoms from the top of the tower. A rich fluid (O) is obtained and a fluid (I) rich in hydrocarbons having 3 or more carbon atoms is obtained from the bottom of the column. A hydrocarbon (O) rich in hydrocarbons and hydrogen having 2 or less carbon atoms is supplied to the cryogenic separation step 33 via the pipe 338, and the fluid rich in hydrogen is removed from the pipe 340. The fluid (N) from which hydrogen has been removed is introduced into the demethanizer tower 34 via a pipe 341 to obtain a fluid rich in methane from the top of the tower, and a fluid rich in hydrocarbons having 2 carbon atoms from the bottom of the tower. Obtained from the pipe 342 and the pipe 343, respectively. On the other hand, the hydrocarbon-rich fluid (I) obtained from the bottom of the deethanizer 35 is introduced into the depropanizer 36 via the pipe 339, and the hydrocarbon having 3 carbons is introduced from the top of the tower. In addition, a fluid rich in hydrocarbons having 4 or more carbon atoms is obtained from the bottom of the column and taken out from the pipe 344 and the pipe 345, respectively.

  In the first to fourth embodiments, the obtained fluid rich in hydrocarbons having 2 carbon atoms and the fluid rich in hydrocarbons having 3 carbon atoms contain the largest amounts of ethylene and propylene, respectively. In addition, paraffin and acetylenes are usually included. Therefore, the concentration of acetylenes is reduced by introducing the fluid into a hydrogenation reactor and hydrogenating at least a part of the acetylenes, and then introducing high purity ethylene and propylene into the rectification column. It is preferable to obtain.

  The purity of ethylene is 95% or more, preferably 99% or more. More preferably, it is 99.9% or more. The purity of propylene is 95% or more, preferably 99% or more. More preferably, it is 99.9% or more.

  The ethylene and propylene thus obtained can be used for all of the ethylene and propylene derivatives that are generally produced. For example, ethylene is produced by chlorination to produce ethylene oxide, ethylene glycol, ethanolamine, glycol ether, etc. by oxidation reaction. For the production of vinyl chloride monomer, 1,1,1-trichloroethane, vinyl chloride resin, vinylidene chloride, for the production of α-olefin, low density or high density polyethylene by polymerization of ethylene, and ethylbenzene by ethylation of benzene Etc., respectively.

  Polyethylene terephthalate can be produced from ethylene glycol produced from ethylene as a raw material, and higher alcohol is obtained by oxo reaction and subsequent hydrogenation reaction using α-olefin as raw material, styrene monomer, ABS resin, etc. from ethylbenzene Can be manufactured. Also, vinyl acetate can be produced by reaction with acetic acid, and acetaldehyde and its derivative ethyl acetate can be produced by Wacker reaction.

  Propylene is produced by polymerization of propylene, for example, for the production of acrylonitrile by ammoxidation, for the production of acrolein, acrylic acid and acrylate by selective oxidation, for the production of oxo alcohols such as normal butyl alcohol and 2-ethylhexanol by oxo reaction. Can be applied to the production of polypropylene and the production of propylene oxide and propylene glycol by the selective oxidation of propylene. Further, acetone can be produced by Wacker reaction, and methyl isobutyl ketone can be produced from acetone. Acetone cyanohydrin can also be produced from acetone, which is ultimately converted to methyl methacrylate. Isopropyl alcohol can also be produced by propylene hydration. In addition, phenol, bisphenol A, and polycarbonate resin can be produced using a cumene produced by alkylating benzene as a raw material.

[Integration of propylene production process and steam cracking process]
<Purification of a fluid containing a hydrocarbon having 2 or less carbon atoms and a hydrocarbon having 3 carbon atoms obtained in a propylene production process in a steam cracking process>
A fluid (B) containing a hydrocarbon having 2 or less carbon atoms and propylene obtained in the propylene production process shown in FIG. 1 is supplied to any of the above-described steam cracking processes. The preferred location for the supply varies depending on the concentration of the compound contained in the fluid (B) and the properties required for ethylene or propylene as the product.

When the carbon dioxide contained in the fluid contains a certain concentration or more with respect to the ethylene contained in the fluid (B), the alkali from the cracker outlet gas (C) (pipe 203) of the steam cracking process shown in FIG. It is preferably supplied to any location between the washing towers 25. Here, the specific concentration is a carbon dioxide concentration that is allowed to be mixed in ethylene of the product, and is usually 5.0 mol ppm, preferably 1.0 mol ppm. This carbon dioxide concentration can be known by a general analytical method such as gas chromatography.
When the fluid (B) is supplied before the alkali cleaning tower 25, at least a part of the carbon dioxide contained in the fluid (B) can be removed in the alkali cleaning tower 25. When the fluid (B) is supplied to a location on the downstream side of the alkali cleaning tower 25, carbon dioxide is mixed into the product ethylene, which is not preferable. The place where the fluid (B) is supplied before the alkali cleaning tower 25 is preferably on the downstream side of the quench tower 23. In this case, the loads on the distillation column 22 and the quenching column 23 are reduced, and the utility cost can be reduced.

  On the other hand, when the carbon dioxide contained in the fluid with respect to the ethylene contained in the fluid (B) is below a certain concentration (usually 0.5 mol ppm or less, preferably 1.0 mol ppm or less). It is preferable to supply the fluid (B) to the downstream side of the alkali cleaning tower 25. In this case, the load on the upstream side including the alkali cleaning tower 25 is reduced, and the service cost can be reduced.

  A preferred supply location of the fluid (B) on the downstream side of the alkali cleaning tower 25 differs depending on the mode of the steam cracking process.

  For example, in the first aspect of the steam cracking process shown in FIG. 3, the space between the desulfurization tower 34 and the gas (F) introduction pipe 301 from which the sulfur compounds and / or carbon dioxide has been removed in the alkali cleaning tower 25 is provided. preferable. On the downstream side from the demethanizer 34, methane contained in the fluid (B) is mixed with the product ethylene, which is not preferable.

  Further, in the second embodiment of the steam cracking process shown in FIG. 4, the space between the desulfurization tower 34 and the gas (F) introduction pipe 317 from which the sulfur compound and / or carbon dioxide has been removed in the alkali cleaning tower 25 is provided. preferable. Among these, the space between the depropanizer 36 and the demethanizer 34 is particularly preferable. In this case, the load on the depropanizer 36 is reduced, and the service cost can be reduced. On the downstream side from the demethanizer 34, methane contained in the fluid (B) is mixed with the product ethylene, which is not preferable.

  Further, in the third embodiment of the steam cracking process shown in FIG. 5, the space between the desulfurization tower 35 and the gas (F) introduction pipe 327 from which the sulfur compound and / or carbon dioxide has been removed in the alkali cleaning tower 25 is provided. preferable. Among these, the space between the depropanizer 36 and the deethanizer 35 is particularly preferable. In this case, the load on the depropanizer 36 is reduced, and the service cost can be reduced. On the downstream side from the deethanizer 35, the hydrocarbon having 3 carbon atoms contained in the fluid (B) is mixed with the product ethylene, which is not preferable.

  In the fourth embodiment of the steam cracking process shown in FIG. 6, the space between the desulfurization tower 35 and the gas (F) introduction pipe 337 from which the sulfur compound and / or carbon dioxide has been removed in the alkali cleaning tower 25 is provided. preferable. On the downstream side from the deethanizer 35, the hydrocarbon having 3 carbon atoms contained in the fluid (B) is mixed with the product ethylene, which is not preferable.

<Utilization of water obtained in the propylene production process in the steam cracking process>
The water-rich fluid (P) obtained in the propylene production process shown in FIG. 1 is supplied to any of the aforementioned steam cracking processes. The place to be supplied is preferably between the distillation column 22 and the steam generator 28 shown in FIG. 2, and more preferably between the distillation column 22 and the process water stripper 27. By supplying the fluid (P) before the process water stripper 27, it is possible to remove the volatile organic compound contained in a trace amount in the water obtained in the propylene production process by the process water stripper 27.

  In this case, the concentration of the organic acid having 1 to 4 carbon atoms contained in the fluid (P) obtained in the propylene production process is preferably 100 ppm by weight or less, and more preferably 50 ppm by weight or less. If the concentration of the organic acid in the fluid (P) is too high, the amount of water discharged to prevent the concentration of the organic acid in the steam generator 28 increases, which is not preferable. Here, the concentration of the organic acid in the fluid (P) can be known by a general analysis technique such as gas chromatography or liquid chromatography.

<Effective use of other fluids>
In the steam cracking process, a low-value fluid (mainly C4 raffinate-2) obtained by removing necessary components from the obtained hydrocarbon fluid having 4 carbon atoms (BB fraction) is hydrogenated and returned to the cracker. Many. In the propylene production process, this low value fluid can be used as a raw material. On the other hand, the fluid extracted in the propylene production process can be effectively used by mixing with the cracker raw material or cracked gasoline of the steam cracking process.

  In the present invention, in this way, it is possible to effectively use each low-value fluid in the propylene production process and the steam cracking process, and an extremely efficient process can be realized.

It is a systematic diagram which shows the propylene manufacturing process which concerns on embodiment of the manufacturing method of the propylene of this invention. It is a systematic diagram which shows the steam cracking process which concerns on embodiment of the manufacturing method of the propylene of this invention. It is a systematic diagram which shows the 1st aspect of the process after the alkali washing tower of the steam cracking process in this invention. It is a systematic diagram which shows the 2nd aspect of the process after the alkali washing tower of the steam cracking process in this invention. It is a systematic diagram which shows the 3rd aspect of the process after the alkali washing tower of the steam cracking process in this invention. It is a systematic diagram which shows the 4th aspect of the process after the alkali washing tower of the steam cracking process in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Reactor 12 Separation and purification process 21 Cracker 22 Distillation tower 23 Quench tower 24 Compressor 25 Alkali washing tower 26 Oil-water separator 27 Process water stripper 28 Steam generator 31 Compressor 32 Gas-liquid separator 33 Cryogenic separation process 34 Demethanization Tower 35 deethanizer 36 depropanizer 37 condensate stripper

Claims (13)

In the method for producing propylene by contacting a mixture containing an olefin having 4 or more carbon atoms and methanol and / or dimethyl ether in a reactor in the presence of a catalyst, the following steps (1), (2), (3 ) And (4), a process for producing propylene comprising :
The following step (2) condenses and removes moisture from the reactor outlet gas (A) by a cooling and compression step, and then, by distillation, a fluid (B) containing a hydrocarbon having 2 or less carbon atoms and propylene, and carbon It is separated into a fluid rich in hydrocarbons having a carbon number of 3 or more, and a fluid rich in hydrocarbons having a carbon number of 3 or more is separated by distillation into a fluid rich in propylene and a fluid rich in hydrocarbons having a carbon number of 4 or more ( Y) and separating
The propylene concentration in the following fluid (B) is in the range of 0.1 to 1.0 times by weight with respect to the concentration of ethylene contained in the fluid (B) .
Step (1): The olefin raw material having 4 or more carbon atoms, the hydrocarbon fluid (X) recycled from Step (3), and methanol and / or dimethyl ether are supplied to the reactor, and propylene, ethylene, Step of obtaining gas (reactor outlet gas) (A) containing butene, paraffin, aromatic compound and water Step (2): Reactor outlet gas (A) from step (1) is 2 or less carbon atoms Are separated into a hydrocarbon- and propylene-containing fluid (B), a propylene-rich fluid, a hydrocarbon-rich fluid (Y) having 4 or more carbon atoms, and a water-rich fluid (P). Step Step (3): Step of recycling part (X) of fluid (Y) to the reactor and extracting the remaining fluid from the process Step (4): Using fluid (B) for the steam cracking process Step of In the method for producing propylene by contacting a mixture containing an olefin having 4 or more carbon atoms and methanol and / or dimethyl ether in a reactor in the presence of a catalyst, the following steps (1), (2), (3 ) And (4), a process for producing propylene comprising :
The following step (2) condenses and removes moisture from the reactor outlet gas (A) by a cooling and compression step, and then, by distillation, a fluid rich in hydrocarbons having 3 or less carbon atoms and carbonization having 4 or more carbon atoms. A fluid rich in hydrocarbons having a carbon number of 3 or less and a fluid rich in hydrocarbons and propylene having a carbon number of 2 or less by distillation (B) separated from a fluid rich in hydrogen (Y) and rich in propylene Including the step of separating into
The propylene concentration in the following fluid (B) is in the range of 0.1 to 1.0 times by weight with respect to the concentration of ethylene contained in the fluid (B) .
Step (1): The olefin raw material having 4 or more carbon atoms, the hydrocarbon fluid (X) recycled from Step (3), and methanol and / or dimethyl ether are supplied to the reactor, and propylene, ethylene, Step of obtaining gas (reactor outlet gas) (A) containing butene, paraffin, aromatic compound and water Step (2): Reactor outlet gas (A) from step (1) is 2 or less carbon atoms Are separated into a hydrocarbon- and propylene-containing fluid (B), a propylene-rich fluid, a hydrocarbon-rich fluid (Y) having 4 or more carbon atoms, and a water-rich fluid (P). Step Step (3): Step of recycling part (X) of fluid (Y) to the reactor and extracting the remaining fluid from the process Step (4): Using fluid (B) for the steam cracking process Step of 3. The method for producing propylene according to claim 1, wherein the steam cracking process comprises a process including the following steps (5), (6), (7) and (8).
Step (5): Supply hydrocarbon to cracker raw material together with dilute steam to cracker and thermally decompose to gas containing ethylene, propylene, other olefins, paraffin, hydrogen, aromatic compound and water from cracker outlet (cracker) Step (6): After cooling the cracker outlet gas (C), the cracker outlet gas (C) is cooled and then introduced into the distillation tower to obtain fuel oil from the bottom of the tower, and the fuel oil is removed from the top of the tower. Step (7): Step (7): Gas (D) is introduced into the quench tower, and the fluid (Q) containing cracked gasoline and water is extracted from the bottom of the tower, and ethylene, propylene, other olefins, Step of obtaining gas (E) containing paraffin, hydrogen, and aromatic compound Step (8): The pressure of gas (E) is increased with a compressor, and an alkali washing tower Obtaining a hydrogen sulfide and / or carbon dioxide to remove the gas (F) The production of propylene according to claim 3 , wherein the steam cracking process is a process including the following steps (9A), (10A), (11A) and (12A) following the step (8). Method.
Step (9A): Step of introducing gas (F) into the cryogenic separation step and separating it into hydrogen and other fluid (G) Step (10A): Introducing fluid (G) into the demethanizer tower, Step of separating methane and other fluid (H) Step (11A): Introducing fluid (H) into a deethanizer, a fluid rich in hydrocarbons having 2 carbon atoms, and carbonization having 3 or more carbon atoms Step of separating into fluid (I) rich in hydrogen Step (12A): Introducing fluid (I) into a depropanizer tower, into a fluid rich in hydrocarbons having 3 carbon atoms and hydrocarbons having 4 or more carbon atoms Separating into rich fluid 4. The production of propylene according to claim 3 , wherein the steam cracking process is a process including the following steps (9B), (10B), (11B) and (12B) following the step (8). Method.
Step (9B): Gas (F) is introduced into a depropanizer and separated into a hydrocarbon-rich fluid (J) having 3 or less carbon atoms and a hydrocarbon-rich fluid having 4 or more carbon atoms. Step Step (10B): Step of introducing fluid (J) into the cryogenic separation step and separating it into hydrogen and a fluid (K) rich in hydrocarbons having 1 to 3 carbon atoms Step (11B): Fluid (K ) Is introduced into the demethanizer tower and separated into methane and a hydrocarbon-rich fluid (L) having 2 to 3 carbon atoms. Step (12B): The fluid (L) is introduced into the deethanizer tower and carbon Separating into a fluid rich in hydrocarbons of number 2 and a fluid rich in hydrocarbons of carbon number 3 The production of propylene according to claim 3 , wherein the steam cracking process is a process including the following steps (9C), (10C), (11C) and (12C) following the step (8). Method.
Step (9C): The gas (F) is introduced into the depropanizer and separated into a hydrocarbon and hydrogen rich fluid (J) having 3 or less carbon atoms and a hydrocarbon rich fluid having 4 or more carbon atoms. Step Step (10C): The fluid (J) is introduced into the deethanizer and separated into a fluid rich in hydrocarbons having 1 to 2 carbon atoms and hydrogen (M) and a fluid rich in hydrocarbons having 3 carbon atoms. Step (11C): Step of introducing the fluid (M) into the cryogenic separation step and separating it into hydrogen and a hydrocarbon-rich fluid (N) having 1 to 2 carbon atoms Step (12C): Fluid ( N) is introduced into a demethanizer and separated into methane and a hydrocarbon-rich fluid containing 2 carbon atoms. The production of propylene according to claim 3 , wherein the steam cracking process is a process including the following steps (9D), (10D), (11D) and (12D) following the step (8). Method.
Step (9D): Gas (F) is introduced into the deethanizer, and a hydrocarbon and hydrogen rich fluid (O) having 2 or less carbon atoms and a hydrocarbon (I) rich in hydrocarbons having 3 or more carbon atoms and Step (10D): Step of introducing fluid (O) into the cryogenic separation step and separating it into hydrogen and a hydrocarbon-rich fluid (N) having 1 to 2 carbon atoms Step (11D): Step of introducing fluid (N) into the demethanizer tower and separating it into methane and a fluid rich in hydrocarbons having 2 carbon atoms Step (12D): introducing fluid (I) into the depropanizer tower and adding 3 carbon atoms Separation into a hydrocarbon-rich fluid and a hydrocarbon-rich fluid with 4 or more carbon atoms The fluid (B) according to any one of claims 3 to 7 , wherein the fluid (B) is supplied from a cracker outlet in the step (6) to any location between the alkali cleaning towers in the step (8). Propylene production method. The propylene fluid according to claim 8 , wherein the fluid (B) is supplied to any point between the top of the quench tower in the step (7) and the alkali washing tower in the step (8). Production method. 5. The propylene according to claim 4 , wherein the fluid (B) is supplied to any location between the top of the alkali washing tower in the step (8) and the demethanizer tower in the step (10A). Manufacturing method. 6. The propylene according to claim 5 , wherein the fluid (B) is supplied to any point between the top of the alkali washing tower in the step (8) and the demethanizer tower in the step (11B). Manufacturing method. The propylene according to claim 6 , wherein the fluid (B) is supplied to any point between the top of the alkali washing tower in the step (8) and the deethanizer in the step (10C). Manufacturing method. The propylene according to claim 7 , wherein the fluid (B) is supplied to any point between the top of the alkali washing tower in the step (8) and the deethanizer in the step (9D). Manufacturing method.

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