JP5928256B2 - Propylene production method - Google Patents

Description

  The present invention relates to a method for producing propylene from a raw material mixture containing ethylene.

  Conventionally, as a method for producing propylene, a naphtha steam cracking method and a fluidized catalytic cracking method of vacuum gas oil are generally carried out. The steam cracking method produces a large amount of ethylene in addition to propylene, and it is difficult to greatly change the production ratio of propylene and ethylene. Therefore, in response to changes in the supply and demand balance of propylene and ethylene, specifically, to increase the production of propylene It was difficult to respond.

Thus, a technique for increasing the production of propylene by producing propylene in a high yield using ethylene as a raw material is desired.
For example, a method for directly producing propylene by bringing ethylene into contact with a catalyst mainly composed of zeolite has been proposed, and it is described that ethylene produced by a steam cracking method or the like can be used (for example, Patent Documents). 1). In addition, a method of combining such a catalytic reaction with a catalyst with the etan racking method has been proposed (Patent Document 2).

JP 2007-291076 A International Publication No. 2010/032609

When performing a reaction to obtain propylene using ethylene obtained from various cracking processes as a raw material as in Patent Document 1 or 2, it is usually assumed that ethylene is taken out and used through a purification process of the cracking process. The
Specifically, the cracked gas obtained in various cracking processes is generally a deethanizer first, so-called “crude ethylene” containing components having a low molecular weight such as hydrocarbons and hydrogen having 2 or less carbon atoms, and carbon. It is separated into hydrocarbons of several or more. The “crude ethylene” is guided to the demethanizer and separated into hydrocarbons having 2 carbon atoms, methane and hydrogen. If necessary, it is further guided to an ethylene rectification column to separate ethane and ethylene.

In other words, propylene is produced using either “crude ethylene”, a hydrocarbon having 2 carbon atoms obtained in a demethanizer, or ethylene separated in an ethylene fractionator (hereinafter referred to as “purified ethylene”). Can be considered.
Purified ethylene has a high purity, but it undergoes the above-described process, so that it requires labor and cost for separation and purification of hydrogen and methane in a demethanizer, and is disadvantageous for industrial production.

The hydrocarbon having 2 carbon atoms obtained in the demethanizer is a mixture of ethylene and ethane that does not affect the catalytic reaction between the catalyst and can be used in the reaction as in the case of purified ethylene. It is the same as refined ethylene in that it is disadvantageous for industrial production in that it passes through the methane tower.
On the other hand, crude ethylene obtained in the deethanizer tower usually contains a large amount of methane and hydrogen in addition to the target ethylene. In a commonly used deethanizer, ethylene and ethane hydrocarbons having 2 carbon atoms are usually extracted from the top of the deethanizer together with hydrogen and methane. At this time, among the components extracted from the top of the column, the component having a relatively high boiling point and having 2 carbon atoms is condensed and refluxed by a condenser usually provided in the deethanizer and recovered in the deethanizer. .

For this reason, crude ethylene contains a large amount of ethylene, but the content of methane and hydrogen is still high. Therefore, if it is directly subjected to a catalytic reaction with a catalyst, a large load is imposed on the compressor in the subsequent purification step.
On the other hand, if the ethylene fraction is extracted from the portion close to the bottom of the deethanizer and used in the propylene production reaction, the content of propylene as a product in the raw material increases, so the yield of propylene that can be extracted as the final product. There is a problem that decreases.

  In view of the above circumstances, the present invention is a method for producing propylene by bringing a raw material mixture containing ethylene into contact with a catalyst, and provides an efficient method for producing propylene that is not burdened in the compression step. This is the issue.

  As a result of intensive studies to solve the above problems, the inventors of the present invention are mainly composed of a fluid containing methane, hydrogen, and a hydrocarbon having 2 carbon atoms and a hydrocarbon having 2 carbon atoms in the production process. Using a distillation column capable of separating a fluid and a fluid mainly composed of hydrocarbons having 3 or more carbon atoms, preferably a distillation column having a side cut stage, a fluid mainly composed of hydrocarbons having 2 carbon atoms is extracted. It has been found that by reacting with a catalyst, propylene can be produced efficiently and the compression load of the apparatus during purification can be reduced, and the present invention has been achieved.

That is, the gist of the present invention is as follows.
[1] A raw material mixture containing ethylene is a fluid (A) containing methane, hydrogen, and a hydrocarbon having 2 carbons, the main component is a hydrocarbon having 2 carbons, and the mole percentage of the hydrocarbon having 2 carbons. Is separated into a fluid (B) higher than the mole percentage of hydrocarbons having 2 carbon atoms in the fluid (A) and a fluid (C) whose main component is a hydrocarbon having 3 or more carbon atoms,
Fluid (B) is introduced into the reactor and brought into contact with the catalyst to obtain a reaction mixture containing propylene,
A method for producing propylene, wherein the reaction mixture is purified in a purification step including a compression step;
[2] The method for producing propylene according to the above [1], wherein the raw material mixture is compressed before the fluids (A) to (C) are separated.
[3] The above-mentioned [1] or [3], wherein the fluids (A) to (C) are separated in a distillation column having a side cut stage, and the fluid (B) is extracted from the side cut stage. 2], a process for producing propylene according to
[4] The method for producing propylene according to any one of [1] to [3], wherein the raw material mixture is obtained by thermal decomposition of naphtha,
[5] The method for producing propylene according to any one of the above [1] to [4], wherein the ethylene content in the fluid (B) is 40 mol% or more,
[6] The method for producing propylene according to any one of [1] to [5] above, wherein the methane / ethylene ratio in the fluid (B) is 0.9 or less in terms of molar ratio,
[7] The propylene production method according to any one of [1] to [6] above, wherein the methane content in the fluid (B) is 35 mol% or less.
[8] The propylene production method according to any one of [1] to [7] above, wherein the hydrogen content in the fluid (B) is 15 mol% or less,
[9] The method for producing propylene according to any one of [1] to [8], wherein the content of the component having 3 or more carbon atoms in the fluid (B) is 15 mol% or less,
[10] A method for producing propylene, comprising the following steps (1) to (4):
Step (1): A raw material mixture containing ethylene, a fluid (A) containing methane, hydrogen, and a hydrocarbon having 2 carbon atoms, a main component being a hydrocarbon having 2 carbon atoms, and a hydrocarbon having 2 carbon atoms The process of separating into the fluid (B) whose mole percentage is higher than the mole percentage of the hydrocarbon having 2 carbon atoms in the fluid (A), and the fluid (C) whose main component is a hydrocarbon having 3 or more carbon atoms (2): introducing the fluid (B) into a reactor and bringing it into contact with a catalyst to obtain a reaction mixture containing propylene;
Step (3): After the reaction mixture is compressed, the reaction mixture is subjected to the step (1) and separated into fluids (A) to (C) together with the raw material mixture containing ethylene. Step (4): The step (1) [11] The method for producing propylene according to [10], further comprising the step of purifying the fluid (C) separated in step 1 and separating propylene [11] and further selectively hydrogenating alkynes and dienes. ,
[12] The method for producing propylene according to the above [11], wherein the hydrogenation is performed by a liquid phase reaction,
[13] A method for producing propylene, comprising the following steps (0) (1 ′) (2 ′) (3 ′) and (4 ′):
Step (0): Step of compressing raw material mixture containing ethylene Step (1 ′): Methane, hydrogen, and hydrocarbon having 2 carbon atoms obtained from the compressed raw material mixture obtained in the step (0) Fluid (A), the main component of which is a hydrocarbon having 2 carbon atoms, and the mole percentage of the hydrocarbon having 2 carbon atoms is higher than the mole percentage of the hydrocarbon having 2 carbon atoms in the fluid (A) (B) and the step of separating the fluid (C) whose main component is a hydrocarbon having 3 or more carbon atoms Step (2 ′): The fluid (B) is introduced into a reactor and brought into contact with a catalyst to produce propylene. Obtaining a reaction mixture comprising:
Step (3 ′): The reaction mixture is subjected to the step (0) and compressed together with the raw material mixture containing ethylene. Step (4 ′): The fluid (C) separated in the step (1 ′) ) And separating propylene [14] A process for producing propylene, comprising the following steps (0), (1 ′), (2 ′), (3 ″) and (4 ′):
Step (0): Step of compressing raw material mixture containing ethylene Step (1 ′): Methane, hydrogen, and hydrocarbon having 2 carbon atoms obtained from the compressed raw material mixture obtained in the step (0) Fluid (A), the main component of which is a hydrocarbon having 2 carbon atoms, and the mole percentage of the hydrocarbon having 2 carbon atoms is higher than the mole percentage of the hydrocarbon having 2 carbon atoms in the fluid (A) (B) and a step of separating the fluid (C), the main component of which is a hydrocarbon having 3 or more carbon atoms, step (2 ′): introducing the fluid (B) into a reactor and bringing it into contact with a catalyst; Obtaining a reaction mixture comprising propylene,
Step (3 ''): Step of compressing the reaction mixture, then subjecting it to the step (1 ′) and separating it into fluids (A) to (C) together with the compressed raw material mixture Step (4 ′): [13] The above [13] to [15], further comprising the step of purifying the fluid (C) separated in the step (1 ′) and separating propylene, and further selectively hydrogenating the alkynes and dienes. [14] The propylene production method according to any one of
[16] The method for producing propylene according to the above [15], wherein the hydrogenation is performed by a liquid phase reaction.

  According to the present invention, the amount of methane and hydrocarbon components having 4 or more carbon atoms in the reaction mixture obtained after the reaction can be minimized. Thereby, it has the effect that the load concerning a compressor is reduced and energy cost is reduced.

It is a manufacturing flow of propylene corresponding to Example 1 of the present invention. It is a manufacturing flow of propylene corresponding to Example 2 of the present invention. 3 is a production flow of propylene corresponding to Comparative Example 1.

Hereinafter, embodiments of the method for producing propylene of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.
In the method for producing propylene of the present invention, the raw material mixture containing ethylene is a fluid (A) containing methane, hydrogen, and a hydrocarbon having 2 carbons, the main component is a hydrocarbon having 2 carbons, and the carbon number is 2 The fluid (B) in which the mole percentage (mol%) of the hydrocarbon is higher than the mole percentage (mol%) of the hydrocarbon having 2 carbon atoms in the fluid (A), and the hydrocarbon whose main component is 3 or more carbon atoms Is separated into fluid (C), and the fluid (B) is introduced into a reactor and brought into contact with a catalyst to obtain a reaction mixture containing propylene. The reaction mixture is purified in a purification step including a compression step. It is characterized by doing.

By using only the fluid (B) in the reaction, the amount of methane and hydrocarbons having 4 or more carbon atoms in the reaction mixture obtained after the reaction can be minimized, and the compressor in the purification process of the reaction mixture can be minimized. The load can be reduced.
Hereinafter, after first explaining the raw material mixture containing ethylene, it will be explained for each step included in the production method.

The raw material mixture containing ethylene used in the present invention (hereinafter sometimes simply referred to as “raw material mixture”) is not particularly limited as long as it contains ethylene. For example, it decomposes hydrocarbons. Can be obtained.
As the hydrocarbon, a known substance capable of producing ethylene can be used. Specifically, for example, ethane, naphtha, liquefied petroleum gas (LPG), atmospheric pressure light oil (AGO), reduced pressure gas oil (VGO) ), Natural gas liquid (NGL), or the like. These can be used alone or in combination of two or more.

Hydrocarbon decomposition can be performed by a known method. For example, any of a thermal decomposition method that decomposes hydrocarbons under a high temperature condition without using a catalyst, a catalytic decomposition method that decomposes using a catalyst, and the like can be used.
The form of the pyrolysis method is not limited. For example, a tube heating method, a steam cracking method, a moving bed method, or the like can be used. Normally, hydrocarbons and steam are mixed and passed through the heating tube at a high speed, and heated from the outside of the tube for decomposition by heating, or hydrocarbons are heated to a little before the decomposition temperature and mixed with the heated steam. A steam cracking method that decomposes with the heat of the steam is used.

Although the reaction temperature in thermal decomposition is not specifically limited, In any system, 600 to 1400 degreeC is preferable normally. Since the hydrocarbon decomposition reaction is generally an endothermic reaction, if the reaction temperature is less than the lower limit, the conversion rate of the hydrocarbon tends to be low and the yield of ethylene tends to decrease.
The reaction pressure in the thermal decomposition is not particularly limited, but is usually 0.001 MPa or more in absolute pressure, preferably 0.2 MPa or more, and preferably 2 MPa or less. If the reaction pressure exceeds the upper limit, the hydrocarbon decomposition reaction may not proceed easily. If the reaction pressure is less than the lower limit, equipment for maintaining a low pressure may be required, and the lower limit or higher is preferable from the viewpoint of economy.

The type of the catalytic cracking method is not limited, and examples thereof include a fixed bed type, a moving bed type, a suspension bed type, and a fluidized bed type.
The reaction temperature in the catalytic cracking is not particularly limited, but is usually preferably 400 ° C to 1000 ° C in any method. If the reaction temperature is less than the lower limit, the hydrocarbon conversion rate tends to be low, and the ethylene yield tends to decrease. If the reaction temperature exceeds the upper limit, the catalyst may be altered and deactivated in a short time.

The reaction pressure in the catalytic cracking is not particularly limited, but is usually preferably 0.001 to 2 MPa in absolute pressure. If the reaction pressure exceeds the upper limit, the hydrocarbon decomposition reaction may not proceed easily. If the reaction pressure is less than the lower limit, equipment for maintaining a low pressure may be required, and the lower limit or higher is preferable from the viewpoint of economy.
Examples of the method for controlling the reaction pressure for decomposing hydrocarbons include a method for controlling the pressure of hydrocarbons and / or steam supplied to the step. As a method for increasing the pressure, a method using a known compressor is generally used. In addition, a compressor here means the apparatus which can raise the pressure of the fluid, ie, the thing which can make compression ratio (discharge pressure / suction pressure) larger than one. As the compressor, a known compressor can be used, for example, a centrifugal pump such as a centrifugal pump, a pump such as a positive displacement pump such as a plunger pump, a turbo compressor such as a centrifugal compressor, or a reciprocating compressor. And compressors such as volume compressors such as screw compressors.

Examples of the method for reducing the pressure include a method using a pressure reducing valve.
Most preferably in the present invention, the raw material mixture obtained by thermal decomposition of naphtha is used. Since the raw material mixture obtained by the thermal decomposition of naphtha usually contains hydrogen, methane, hydrocarbons having 2 carbon atoms, and hydrocarbons having 3 or more carbon atoms, by using the production method of the present invention, it is possible to efficiently produce propylene. This is because it can be manufactured.

  Components other than ethylene contained in the raw material mixture vary depending on the raw material used and the decomposition method, and are not particularly limited, but usually include various hydrocarbons other than ethylene, hydrogen, water, etc. For example, alkanes such as methane, ethane and propane, alkenes such as propylene and butene, alkynes such as acetylene, dienes such as butadiene, hydrocarbons having 5 to 11 carbon atoms including benzene, toluene and xylene (gasoline) Component), hydrocarbons having 10 to 11 or more carbon atoms (decomposed fuel oil), and the like.

Further, the raw material mixture in the present invention may contain methanol, dimethyl ether, and ethanol. Methanol, dimethyl ether, and ethanol contained in the reaction mixture are easily converted to ethylene due to acid sites present in the catalyst of the present invention described later.
The raw material mixture in the present invention may contain an alkali metal, a sulfur compound, a heavy metal, etc., but the content of these components is preferably small and more preferably not contained.

The content of the alkali metal is not particularly limited, but is usually 1 ppm or less, preferably 0.1 ppm or less. This is because an alkali metal works as a poisoning substance for the catalyst, and therefore, using a raw material with less content has a longer catalyst life and better productivity.
The content of the sulfur compound is not particularly limited, but is usually 20 ppm or less, preferably 1 ppm or less, more preferably 0.5 ppm or less as the total sulfur content measured by the chemiluminescence method. Since the sulfur compound may be mixed in the propylene of the product in a form contained in the raw material or in a form changed by the reaction and may adversely affect a polypropylene production catalyst or the like, a raw material having a low content is more preferable.
The content of heavy metals and the like is not particularly limited, but is usually 1 ppm or less. Since heavy metals and the like may cause changes in catalyst performance and catalyst deterioration, raw materials having a low content are preferable. In addition, content (ppm) of the said substance is a mass reference | standard.

  In the production method of the present invention, the raw material mixture is a fluid (A) containing methane, hydrogen and a hydrocarbon having 2 carbons, the main component being a hydrocarbon having 2 carbons, and a hydrocarbon having 2 carbons. Is separated into a fluid (B) having a mole percentage higher than that of the hydrocarbon having 2 carbon atoms in the fluid (A), and a fluid (C) whose main component is a hydrocarbon having 3 or more carbon atoms, The fluid (B) is introduced into the reactor and brought into contact with the catalyst. The raw material mixture may directly separate the fluids (A) to (C), or may be separated after being compressed in advance. Depending on the production method and origin, the pressure of the raw material mixture varies and may not reach a pressure suitable for separation of fluids (A) to (C), so the raw material mixture is compressed and the compressed raw material mixture is separated. It is preferable to do.

In the present invention, “main component” is a comparison of five components of “hydrogen”, “methane”, “ethane”, “ethylene”, and “total amount of hydrocarbons having 3 or more carbon atoms” in the target fluid. The component which is determined and contained most in the target fluid in molar percentage.
In the present invention, “the hydrocarbon having 2 carbon atoms is the main component” means that the sum of “ethane” and “ethylene” is the main component.

  The separation method of the raw material mixture containing ethylene or the compressed raw material mixture is not particularly limited, but can be distilled using, for example, a distillation column capable of side cut, and specifically has a so-called side cut stage. The method of introduce | transducing into a distillation tower and isolate | separating into said each fluid of (A)-(C) is mentioned. A side cut generally means an operation of extracting a normal middle fraction from the middle part of a distillation column in order to distill and separate a system composed of three or more components into a light fraction, a middle fraction and a heavy fraction. The part from which the middle distillate is extracted is called a “side cut stage” and is also called a side stream.

As the distillation column used in the separation step, ordinary ones can be used as other characteristics.
Alternatively, a distillation column having no side cut stage can be used. A raw material mixture containing ethylene or a compressed raw material mixture is introduced into a distillation column equipped with a condenser at the top of the column, and the fluid (C) is withdrawn from the bottom of the column, and the others are the first stage (the top of the column). ) From the top of the tower. And a part of the top vapor | steam is extracted as said fluid (B) from between the condenser which a tower top part and a distillation tower have, and the remainder is guide | induced to a condenser. Steam (referred to as distilled steam) obtained through the condenser is extracted as the fluid (A). Further, the liquid obtained through the condenser is refluxed to the distillation column (hereinafter referred to as reflux liquid). By adopting such a method, the same effect as that obtained by performing the side cut in the distillation column having the side cut stage can be obtained.

As still another method, in the distillation column not having the side cut stage, a part of the reflux liquid from the condenser to the distillation column can be extracted as the fluid (B).
The number of stages in the distillation column is not particularly limited, but is usually 20 or more, preferably 30 or more, usually 100 or less, preferably 80 or less. In the present invention, the number of stages of the distillation column means the number of stages counted from the top with the column top as the first stage.

  In the production method of the present invention, the fluid (B) is preferably obtained from the middle distillate, that is, the side cut stage. The position of the side cut stage is that the main component of the obtained fraction is a hydrocarbon having 2 carbon atoms, and the mole percentage (mol%) of the hydrocarbon having 2 carbon atoms is 2 carbon atoms in the fluid (A). It is not particularly limited as long as it is higher than the mole percentage (mol%) of the hydrocarbon, and a position where a component mainly composed of ethylene is obtained is preferable. There is a gas phase or liquid phase fluid in the side cut stage, but the phase extracted by the side cut is not particularly limited as long as the main component is a hydrocarbon having 2 carbon atoms. It may be a mixed phase.

The fluid (A) containing methane, hydrogen, and a hydrocarbon having 2 carbon atoms preferably has the highest total content (molar percentage) of methane and hydrogen in its components.
The methane content (mole percentage) in the fluid (A) is not particularly limited, but is usually 10 mol% or more and 50 mol% or less, and the hydrogen hydrogen mole percentage is usually 10 mol% or more and 50 mol% or less. It is.

The fluid (A) contains a hydrocarbon having 2 carbon atoms (ethane, ethylene) or the like. The mole percentage of the hydrocarbon having 2 carbon atoms in the fluid (A) is not particularly limited as long as it is lower than the mole percentage of the hydrocarbon having 2 carbon atoms in the fluid (B), but is usually 80 mol% or less, preferably Is 50 mol% or less, and usually 1 mol% or more.
The fluid (A) may be any of a gas phase, a liquid phase, or a mixed phase thereof, and is preferably a gas phase.

A fluid (B) whose main component is a hydrocarbon having 2 carbon atoms and whose mole percentage of the hydrocarbon having 2 carbon atoms is higher than the mole percentage of the hydrocarbon having 2 carbon atoms in the fluid (A) is in the fluid. Contains the most C2 hydrocarbons. The mole percentage (mol%) of the C 2 hydrocarbon in the fluid (B) is higher than the mole percentage (mol%) of the C 2 hydrocarbon in the fluid (A). The difference between the mole percentage (mol%) of the hydrocarbon having 2 carbon atoms in the fluid (B) and the mole percentage (mol%) of the hydrocarbon having 2 carbon atoms in the fluid (A) is not particularly limited. The mole percentage (mol%) of the hydrocarbon having 2 carbon atoms in the fluid (B) is usually 1 mol% or more higher than the mole percentage (mol%) of the hydrocarbon having 2 carbons in the fluid (A), preferably Is 5 mol% or more higher, more preferably 10 mol% or more. By increasing the concentration of hydrocarbons having 2 carbon atoms in the fluid (B), it is desirable in that the amount of recycled components other than propylene described later can be reduced.
The fluid (B) contains at least ethylene. As the hydrocarbon having 2 carbon atoms, either ethane or ethylene may be contained in a large amount, but it is usually preferable that ethylene is the most and ethylene is contained most. Although it does not limit as ethylene content in a fluid (B), 40 mol% or more is preferable. This is because the yield of propylene is improved in the contact reaction with the catalyst described later. Since ethane is inactive in contact with the catalyst to be described later, it may be mixed with ethylene, and the abundance ratio of ethylene and ethane is not particularly limited, but is usually an ethylene / ethane molar ratio of 0. 8 or more. If it is less than the said lower limit, a propylene may not fully be obtained.

The fluid (B) is not particularly limited as a component other than the hydrocarbon having 2 carbon atoms, but usually includes methane, a hydrocarbon having 3 or 4 carbon atoms, hydrogen, or the like. The content of each component is usually less than the hydrocarbon having 2 carbon atoms, and preferably less than the content of ethylene.
The methane content is preferably less than the mole percentage of ethylene, preferably less than or equal to 0.9, more preferably less than or equal to 0.8 in terms of the methane / ethylene mole ratio. Although it does not specifically limit as methane content in (B), It is preferable that it is 35 mol% or less.

The hydrogen content in the fluid (B) is preferably less than the mole percentage of ethylene, and the content is not particularly limited, but is usually 15 mol% or less.
If the content of methane and hydrogen is higher than the content of ethylene, a sufficient amount of propylene cannot be obtained in the reactor, the efficiency of the entire process is deteriorated, or in the purification step of the reaction mixture When a large amount of light-boiling methane enters the compressor, the load on the compressor increases and energy consumption may increase.

The hydrocarbon having 3 or more carbon atoms in the fluid (B) is preferably less than the ethylene content, and preferably 15 mol% or less. If there are more hydrocarbons having 3 or more carbon atoms than ethylene, the amount of propylene in the reaction mixture, which will be described later, decreases, and the efficiency of the entire process may deteriorate.
The fluid (C) whose main component is hydrocarbon having 3 or more carbon atoms has the highest mole percentage of hydrocarbon having 3 or more carbon atoms in the component. Usually, it is preferable that the hydrocarbon having 3 carbon atoms is the largest and the molar percentage of propylene is the largest.

The fluid (C) is not particularly limited as a component other than hydrocarbons having 3 or more carbon atoms, but includes hydrocarbons having 1 or 2 carbon atoms, water, and the like.
The phase of the fluid (C) is not particularly limited, and may be a gas phase, a liquid phase, or a mixed phase thereof, and is preferably a liquid phase.

Subsequent to the separation step of the fluids (A) to (C) described above, the fluid (B) is brought into contact with the catalyst and reacted to obtain a reaction mixture containing propylene. The reaction for obtaining the reaction mixture is described in detail in the section <Step (2)> in [First Embodiment].
The obtained reaction mixture is purified in a purification step including a compression step to obtain propylene as a target product. For the purification step including the compression step, a known process may be employed, and for example, it can be performed by the method described in HYDROCARBON PROCESSING, p.112-114, 3, 1999, etc. Further, as shown in first to third embodiments described later, after the reaction mixture is compressed, it may be recycled and separated and purified during the reaction process.

Examples of the compressor used in the compression step in the refining step include the same ones described in the section of pressure control in the hydrocarbon decomposition reaction.
As described above, the present invention removes fluid (A) and fluid (C) from the raw material mixture in advance, and produces propylene using fluid (B), thereby compressing the reaction product in the compression step. The point which does not produce an excessive load to a compressor is preferable.

<Propylene production process>
Next, although the manufacturing method of the propylene of this invention is demonstrated more concretely, this invention is not limited to these embodiments.
[First Embodiment]
As a 1st embodiment of this invention, the manufacturing method of propylene including the following process (1)-(4) is mentioned.

Step (1): A raw material mixture containing ethylene, a fluid (A) containing methane, hydrogen, and a hydrocarbon having 2 carbon atoms, a main component being a hydrocarbon having 2 carbon atoms, and a hydrocarbon having 2 carbon atoms A step of separating a fluid (B) whose mole percentage is higher than the mole percentage of hydrocarbons having 2 carbon atoms in the fluid (A) and a fluid (C) whose main component is a hydrocarbon having 3 or more carbon atoms. 2): introducing the fluid (B) into a reactor and bringing it into contact with a catalyst to obtain a reaction mixture containing propylene;
Step (3): After the reaction mixture is compressed, the reaction mixture is subjected to the step (1) and separated into fluids (A) to (C) together with the raw material mixture containing ethylene. Step (4): The step (1) The step of purifying the fluid (C) separated in step and separating propylene In this embodiment, when attention is paid to the reaction mixture obtained in step (2), the whole of steps (3) and (4) Since the reaction mixture is compressed in the step (3), the entire steps (3) and (4) correspond to the “purification step including the compression step”.

<Step (1)>
In step (1), a raw material mixture containing ethylene is mixed with a fluid whose main component is methane or hydrogen (
A), a fluid (B) whose main component is a hydrocarbon having 2 carbon atoms, and a fluid (C) whose main component is a hydrocarbon having 3 or more carbon atoms.
The raw material mixture, the fluids (A) to (C), and the separation method are as described above.

<Step (2)>
The fluid (B) mainly composed of a hydrocarbon having 2 carbon atoms is introduced into a reactor and brought into contact with a catalyst to obtain a reaction mixture containing propylene (hereinafter sometimes simply referred to as “reaction mixture”). This step is referred to as step (2).
As the catalyst, a known catalyst can be used, and is not particularly limited as long as it satisfies the object of the present invention. However, it is usually a solid catalyst having a Bronsted acid point (hereinafter referred to as “solid acid catalyst”). May be used). For example, clay minerals such as kaolin; those obtained by impregnating and supporting an acid such as sulfuric acid and phosphoric acid on a carrier such as clay minerals; acidic ion exchange resins; zeolites; mesoporous silica alumina such as Al-MCM41; ITQ-2 etc. Solid acid catalysts such as lamellar zeolite, and more specifically, for example, catalysts disclosed in Japanese Patent Application Laid-Open No. 2007-291076 and International Publication No. 2010/128644.

  Among them, a catalyst disclosed in International Publication No. 2010/128644 is preferable, specifically, a zeolite having a pore diameter of less than 0.5 nm is preferable, and a zeolite having an 8-membered ring or 9-membered ring structure is more preferable. preferable. As the zeolite, aluminosilicate is preferable. Most preferred is a catalyst obtained by subjecting an aluminosilicate having a CHA structure to a silylation treatment.

In the production method of the present invention, the form of the reactor to be used is not particularly limited, but usually a continuous fixed bed reactor or fluidized bed reactor is selected. A fluidized bed reactor is preferred. A method using a single reactor or a method using a plurality of reactors arranged in series or in parallel may be used.
In addition, when packing the above-mentioned catalyst into the fluidized bed reactor, in order to keep the temperature distribution of the catalyst layer small, particulates inert to the reaction such as quartz sand, alumina, silica, silica-alumina, etc. are mixed with the catalyst. And may be filled. In this case, there is no particular limitation on the amount of granular material inactive to the reaction such as quartz sand. In addition, it is preferable that this granular material is a particle size comparable as a catalyst from the surface of uniform mixing property with a catalyst.

In order to disperse the heat generated by the reaction, the reactor may be divided and supplied with the fluid (B) mainly composed of a hydrocarbon having 2 carbon atoms obtained in the step (1).
When a fluidized bed reactor is selected, a catalyst regenerator is attached to the reactor, the catalyst extracted from the reactor is continuously sent to the regenerator, and the catalyst regenerated in the regenerator is continuously reacted to the reactor. It is preferable to carry out the reaction while returning to pH.
Here, the catalyst regenerator is an apparatus for regenerating the catalyst extracted from the reactor by the method described in the section of the catalyst regeneration method.

(Substrate concentration)
There is no particular limitation on the concentration of ethylene (that is, the substrate concentration) in the fluid (B) supplied to the reactor, but ethylene is preferably 90 mol% or less in the total supply components. More preferably, it is 5 mol% or more and 70 mol% or less. When this substrate concentration is too high, the production of aromatic compounds and paraffins becomes remarkable, and the yield of propylene tends to decrease. If the substrate concentration is too low, the reaction rate becomes slow, so a large amount of catalyst is required, and the reactor tends to be too large.

Therefore, it is preferable to dilute ethylene with a diluent as necessary so as to obtain such a substrate concentration.
Diluents include helium, argon, nitrogen, carbon monoxide, carbon dioxide, hydrogen, water, paraffins, hydrocarbons such as methane, aromatic compounds, and mixtures thereof. Can be mentioned. Among these, it is preferable that water (water vapor) coexists.
As such a diluent, impurities derived from the raw material mixture may be used as they are, or a separately prepared diluent may be mixed with the fluid (B).
The diluent may be mixed with the fluid (B) before entering the reactor, or may be supplied to the reactor separately from the fluid (B).

(Space velocity)
The space velocity mentioned here is the flow rate (weight / hour) of ethylene as a reaction raw material per weight of the catalyst (catalytic active component), and the weight of the catalyst is the 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 space velocity is preferably between 0.01 hr ^-1 for 500HR ^-1, more preferably between 0.1 hr ^-1 to 100 Hr ^-1. When the space velocity is too high, the amount of ethylene in the reaction mixture described later increases, and the propylene yield tends to be low. On the other hand, when the space velocity is too low, undesirable by-products such as paraffins are produced, and the propylene yield tends to decrease.

(Reaction temperature)
The lower limit of the reaction temperature is usually about 200 ° C. or higher, preferably 300 ° C. or higher, and the upper limit of the reaction temperature is usually 700 ° C. or lower, preferably 600 ° C. or lower. If the reaction temperature is less than the lower limit, the reaction rate tends to be low, a large amount of unreacted raw material tends to remain, and the yield of propylene may also decrease. On the other hand, when the reaction temperature exceeds the above upper limit, the yield of propylene may decrease.

(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. When the reaction pressure is too high, the amount of undesired by-products such as paraffins increases, and the yield of propylene tends to decrease. If the reaction pressure is too low, the reaction rate tends to be slow.

(Reaction mixture)
As the reactor outlet gas, a reaction mixture containing propylene is obtained. The reaction mixture contains propylene, ethylene, by-products and optionally a diluent. The propylene concentration in the reaction mixture is usually 1 to 95% by weight, preferably 2 to 80% by weight.
This usually contains ethylene, but it is preferable that at least a part of this ethylene is recycled to the reactor and reused as a reaction raw material.
Examples of by-products include olefins having 4 or more carbon atoms, paraffins, aromatic compounds, and water.

(Catalyst regeneration method)
The method for regenerating the catalyst is not particularly limited as long as coke attached to the catalyst can be removed, but it is preferable to regenerate by bringing the catalyst into contact with a gas containing hydrogen. By regenerating with a gas containing hydrogen, it is possible to regenerate the catalyst while maintaining a high propylene selectivity. For the regeneration method using hydrogen, for example, the method and regeneration conditions described in JP 2010-205579 A can be applied.

The form of the regenerator is not particularly limited, and a continuous fixed bed regenerator or a fluidized bed regenerator is usually selected. A fluidized bed regenerator is preferable.
When regenerating in a fixed bed, it is preferable to regenerate by flowing a regeneration gas while leaving the catalyst in the reactor without removing the catalyst. Alternatively, the catalyst may be once extracted and charged into a regenerator separate from the reactor, and then regenerated by contacting with the regeneration gas. In the case of moving bed or fluidized bed, a catalyst regenerator is attached to the reactor, the catalyst extracted from the reactor is continuously sent to the regenerator, and the catalyst regenerated in the regenerator is continuously reacted to the reactor. It is preferable to carry out the reaction while returning to pH. Further, the reaction and regeneration may be performed while replenishing the catalyst in the system or purging a part from the system.

<Step (3)>
After compressing the reaction mixture containing propylene obtained in the step (2), the reaction mixture is subjected to the step (1) and separated into the fluids (A) to (C) together with the raw material mixture containing ethylene. This step is referred to as step (3).
The reaction mixture may be mixed with the raw material mixture in advance and introduced into the distillation column, or may be introduced into the distillation column separately from the raw material mixture.
As the compressor used for the compression operation in this step (3), the same apparatus as mentioned in the section of pressure control in the hydrocarbon decomposition reaction can be used.

<Step (4)>
Of the fluids (A) to (C) separated in the step (1), the fluid (C) is purified to separate propylene as the target product. This step is referred to as step (4).
The fluid (C) includes a component derived from the raw material mixture and a component derived from the reaction mixture obtained in the step (2).
The purification method is not particularly limited, but various known separation and purification methods can be used.
Usually, it is removed from heavier components in the fluid (C). Hereinafter, description will be made using a general separation and purification process.

If necessary, the fluid (C) is introduced into a gasoline tower and cooled so that heavy oil (usually a hydrocarbon component having 10 to 11 or more carbon atoms) and gas other than the heavy oil component (usually normal) , Hydrocarbon components having 9 to 10 carbon atoms and lighter ones).
Next, the gas other than the heavy oil component usually passes through the quench tower, and then moisture, gasoline component (usually hydrocarbon component having 5 to 10 carbon atoms), and light component (usually carbonization having 4 or less carbon atoms). Hydrogen).
If the heavy oil and gasoline components contained in the fluid (C) are low in concentration, the fluid (C) may be directly supplied to the subsequent steps without passing through the gasoline tower and / or the quench tower. .

  In order to isolate the desired propylene from the above light components, for example, it is introduced into separation and purification equipment such as a deethanizer and a depropanizer as in the naphtha pyrolysis process, and recovered according to each component. , Purification, recycling, discharge, etc. In a general process, light components are introduced into a demethanizer tower, separated into methane and other components, and components other than methane are introduced into the deethanizer tower. In the deethanizer, it is mainly separated into a component having 2 carbon atoms and a component having 3 or more carbon atoms. Then, it is separated into a component having 3 or more carbon atoms and a component having 4 or more carbon atoms in a depropanizer, and the obtained component having 3 or more carbon atoms is distilled to separate propylene.

Some or all of the components other than propylene (olefins, paraffins, etc.), especially ethane and ethylene, are desirably recycled during the process.
Specifically, a component containing ethane and / or ethylene,
It mixes beforehand in a raw material mixture, and uses for the separation process in process (1).
Separately from the raw material mixture, it is subjected to a separation step in step (1).
Premixed in fluid (B) and fed to the reactor in step (2),
Separately from the fluid (B), it is supplied to the reactor in step (2).
Etc. are considered.

In addition, when obtaining a raw material mixture by decomposition | disassembly of a hydrocarbon, it is preferable to use the said component before a process (1), ie, the decomposition | disassembly process of a hydrocarbon, from a viewpoint of the recycling efficiency of ethane. Ethane is preferred because it easily converts to ethylene in the hydrocarbon cracking step, leading to an increase in the reaction raw materials in the production of propylene.
From the viewpoint of ethylene recycling efficiency, it may be mixed in the fluid (B) in advance and supplied to the reactor in the step (2), or supplied to the reactor in the step (2) separately from the fluid (B). preferable.

[Second Embodiment]
As a 2nd embodiment of this invention, the manufacturing method of propylene including the following process (0), (1 '), (2'), (3 ') and (4') is mentioned.
Step (0): Step of compressing raw material mixture containing ethylene Step (1 ′): Methane, hydrogen, and hydrocarbon having 2 carbon atoms obtained from the compressed raw material mixture obtained in the step (0) A fluid (A) containing a main component of a hydrocarbon having a carbon number of 2 and a mole percentage of the hydrocarbon of carbon number 2 higher than the mole percentage of the hydrocarbon of carbon number 2 in the fluid (A) ( B) and a process of separating the fluid (C) whose main component is a hydrocarbon having 3 or more carbon atoms Step (2 ′): introducing the fluid (B) into a reactor and bringing it into contact with a catalyst to produce propylene Obtaining a reaction mixture comprising:
Step (3 ′): The reaction mixture is subjected to the step (0) and compressed together with the raw material mixture containing ethylene. Step (4 ′): The fluid (C) separated in the step (1 ′) In this embodiment, when attention is paid to the reaction mixture obtained in step (2 ′), all subsequent steps, that is, step (3 ′), step (0), step The whole of (1 ′) and step (4 ′) corresponds to “reaction mixture purification step”, and the reaction mixture is compressed in step (0). Corresponding to a “purification step comprising”.

<Process (0)>
Step (0) is a step of compressing the raw material mixture.
The separation step in the step (1 ′) is usually performed by distillation as described above. However, in order to increase the pressure of the raw material mixture introduced into the step (1 ′) to a pressure suitable for the distillation process, the step (0 ′) ) Is preferably provided.

The pressure of the compressed raw material mixture obtained in the step (0) is usually 0.5 MPa or more, preferably 2 MPa or more, and usually 5 MPa or less, preferably about 4 MPa or less.
When the pressure is too high, the pressure during the reaction in the subsequent step (2 ′) also increases, and the proportion of by-products tends to increase. On the other hand, if it is too low, it may be difficult to adjust to an appropriate pressure during distillation in the separation step of the step (1 ′) and the purification step after the step (3 ′).
Specifically, for example, when the distillation operation is performed in the step (4 ′), the compression operation may be performed in order to adjust the pressure of the fluid to be purified (fluid (C)) to a range suitable for distillation. The load on the compressor performing the operation may be excessive.

In addition, since the water | moisture content in a raw material mixture may liquefy and precipitate by compression operation of this process (0), you may remove the said water | moisture content as needed. The amount of water in the raw material mixture is usually 0.025 or more, preferably 0.1 or more, more preferably 0.5 or more, and usually 15 or less, with respect to ethylene in the raw material mixture. Preferably it is 10 or less, More preferably, it is about 5 or less. If the amount of water is too large, the reaction rate in the subsequent step (2 ′) may decrease, the yield of the target product (propylene) may decrease, and problems such as deterioration of the catalyst by reacting with water may occur. there is a possibility.

<Process (1 ')>
The step (1 ′) is the same as the step (1) in the first embodiment except that the raw material mixture after compression obtained in the step (0) is used.
<Process (2 ')>
The step (2 ′) is the same as the step (2) in the first embodiment except that the fluid (B) obtained in the step (1 ′) is used.

<Process (3 ')>
Step (3 ′) is a step of subjecting the reaction mixture obtained in step (2 ′) to step (0) and compressing it together with the raw material mixture containing ethylene. The reaction mixture may be mixed with the raw material mixture in advance and introduced into the compressor, or may be introduced into the compressor separately from the raw material mixture.
<Process (4 ')>
The step (4 ′) is a step of purifying the fluid (C) separated in the step (1 ′) and separating propylene as a target product. The fluid (C) includes a component derived from the raw material mixture and a component derived from the reaction mixture obtained in the step (2 ′).

The method for separating and purifying propylene from the fluid (C) is the same as step (4) in [First embodiment].
Part or all of the components (olefin, paraffin, etc.) other than propylene obtained in step (4 ′), particularly ethane and ethylene are preferably recycled during the process.
Specifically, a component containing ethane and / or ethylene,
It mixes beforehand in a raw material mixture, and uses for the compression process in a process (0).
Separately from the raw material mixture, it is subjected to the compression step in step (0).
Mixed in a pre-compressed raw material mixture and subjected to a separation step in step (1 ′),
Separately from the compressed raw material mixture, it is subjected to a separation step in step (1 ′).
After being mixed in fluid (B) in advance, it is fed to the reactor in step (2 ′).
Separately from fluid (B), it is fed to the reactor in step (2 ′).
Etc. are considered.

In addition, when obtaining a raw material mixture by decomposition | disassembly of a hydrocarbon, it is preferable to use the said component before a process (0), ie, the decomposition | disassembly process of a hydrocarbon, from a viewpoint of the recycling efficiency of ethane. Ethane is preferred because it easily converts to ethylene in the hydrocarbon cracking step, leading to an increase in the reaction raw materials in the production of propylene.
From the viewpoint of ethylene recycling efficiency, after mixing in fluid (B) in advance, it is supplied to the reactor in step (2 ′), or supplied to the reactor in step (2 ′) separately from fluid (B). It is preferable to do.

[Third Embodiment]
As a 3rd embodiment of the present invention, the manufacturing method of propylene including the following process (0), (1 '), (2'), (3 ''), and (4 ') is mentioned.
Step (0): Step of compressing raw material mixture containing ethylene Step (1 ′): Methane, hydrogen, and hydrocarbon having 2 carbon atoms obtained from the compressed raw material mixture obtained in the step (0) A fluid (A) containing the main component of a hydrocarbon having a carbon number of 2 and a mole percentage of the hydrocarbon having a carbon number of 2 higher than that of the hydrocarbon of carbon number 2 in the fluid (A) (B) And a process of separating the fluid (C), the main component of which is a hydrocarbon having 3 or more carbon atoms, step (2 ′): introducing the fluid (B) into a reactor, bringing it into contact with a catalyst, and containing propylene Obtaining a reaction mixture;
Step (3 ''): Step of compressing the reaction mixture, then subjecting it to the step (1 ′) and separating it into fluids (A) to (C) together with the compressed raw material mixture Step (4 ′): The step of purifying the fluid (C) separated in the step (1 ′) and separating the propylene In this embodiment, when attention is paid to the reaction mixture obtained in the step (2 ′), The entire process, that is, the process (3 ″), the process (1 ′) and the process (4 ′) corresponds to the “purification process of the reaction mixture”, and the reaction mixture is compressed in the process (3 ″). The whole of these steps corresponds to the above-described “purification step including the compression step”.

  This embodiment is the same as the second embodiment except for the step (3 ″). That is, the difference is that the reaction mixture obtained in the step (2 ') is pre-compressed and then subjected to the step (1') instead of the step (0). The compressed reaction mixture may be mixed with the raw material mixture in advance and used for the step (1 '), or may be used separately from the raw material mixture for the step (1'). As the compressor used for the compression operation in the step (3 ″), the same apparatus as mentioned in the section of pressure control in the hydrocarbon decomposition reaction can be used. The pressure of the reaction mixture after compression is preferably the same as that of the “compressed raw material mixture” supplied to step (1 ′).

Also in this embodiment, part or all of the components (olefin, paraffin, etc.) other than propylene obtained in step (4 ′), particularly ethane and ethylene are preferably recycled during the process.
Specifically, a component containing ethane and / or ethylene,
After being mixed in the raw material mixture in advance, it is subjected to the compression step in step (0).
Separately from the raw material mixture, it is supplied to the compression step in step (0).
After mixing in a pre-compressed raw material mixture, it is subjected to a separation step in step (1 ′).
Separately from the compressed raw material mixture, it is subjected to a separation step in step (1 ′).
After being mixed in fluid (B) in advance, it is fed to the reactor in step (2 ′).
Separately from fluid (B), it is fed to the reactor in step (2 ′).
Etc. are considered.

In addition, when obtaining a raw material mixture by decomposition | disassembly of a hydrocarbon, it is preferable to use the said component before a process (0), ie, the decomposition | disassembly process of a hydrocarbon, from a viewpoint of the recycling efficiency of ethane. Ethane is preferred because it easily converts to ethylene in the hydrocarbon cracking step, leading to an increase in the reaction raw materials in the production of propylene.
From the viewpoint of ethylene recycling efficiency, after mixing in fluid (B) in advance, it is supplied to the reactor in step (2 ′), or supplied to the reactor in step (2 ′) separately from fluid (B). It is preferable to do.

[Other processes]
Alkynes such as acetylene in the fluid (B) subjected to the reaction in the reaction step (corresponding to step (2) and step (2 ′) in each of the above-described embodiments) in which the fluid (B) is brought into contact with the catalyst In addition, when dienes such as butadiene are contained, these may come into contact with the catalyst and cause coke, which may reduce the activity of the catalyst. In order to prevent this, it is preferable to further include a step of reducing alkynes and dienes, more preferably a step of selectively hydrogenating them.

This reduction step may be performed in any step or before and after any step in the process of the present invention as long as the content of alkynes and dienes in the fluid (B) supplied to the reaction step can be reduced. For example, in each of the above-described embodiments, the step (2) or the step (2 ′) (
Before reaction step), before step (1) or step (1 ′) (separation step into fluids (A) to (C)), before step (0) (compression step of raw material mixture), or step ( 2) or before the reaction mixture obtained in the step (2 ′) is subjected to a process prior to the step (2) or the step (2 ′). Among these, the step (2) or before the step (2 ′) (reaction step) is particularly preferable.

  The reduction step (preferably selective hydrogenation) can be performed by appropriately selecting a conventionally known method. When the component to be reduced is obtained in a liquid, the hydrogenation is preferably performed in a liquid phase.

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the examples described below.
Examples in the present invention were simulated by ASPEN PLUS. The simulation used the RSTOIC mode. The steps used for studying the examples are shown in FIGS.
In the simulation, the composition of the naphtha cracker cracked gas 101 from which components having 5 or more carbon atoms were removed as a raw material mixture through a gasoline tower and a quench tower was defined as shown in Table 1.

Example 1
Hereinafter, a description will be given with reference to FIG.
The cracked gas 101 (163 T / H, 35 ° C., 0.15 MPa) is mixed with a propylene-rich fluid 106 (corresponding to a reaction mixture, 41.7 T / H), which will be described later. And was subjected to heat exchange to 14 ° C. and 3.5 MPa. Condensed components (including hydrocarbon components having 5 or more carbon atoms, including propylene 4.7 T / H) generated in the process of being compressed by the cracked gas compressor 1 are removed, and hydrocarbons having 3 or more carbon atoms, which will be described later, as a main component. The fluid (C) 103 was mixed (not shown). The obtained compressed gas 102 (corresponding to the compressed raw material mixture) is introduced into the 16th stage from the top of the deethanizer 2 having 39 stages and side cut stages, and is a fluid mainly composed of methane. (A) (104), fluid (B) (105) mainly containing hydrocarbons having 2 carbon atoms, fluid (C) (103) mainly containing hydrocarbons having 3 or more carbon atoms, fluid (B) was extracted from the seventh stage of the deethanizer tower.

The composition of each component 102-105 is shown in Table 2.
From the seventh stage of the deethanizer 2 is a fluid (B) mainly composed of a hydrocarbon having 2 carbon atoms.
05 was extracted, and although not shown, acetylene was converted into ethane or ethylene by hydrogenation in a hydrogenation reactor, and then introduced into the reactor 5. In the reactor 5, assuming that the catalyst disclosed in Preparation Example 1 of International Publication 2010/128644 is used, the composition of the stream at the inlet and outlet of the reactor 5 is the composition described in Table 3. Simulation was performed in mode. The obtained propylene-rich fluid 106 (41.7 T / H) was mixed with the naphtha cracker cracked gas 101 and introduced into the cracked gas compressor 1 as described above. The power consumption in the cracked gas compressor 1 was 25.4 MW.

A gas phase component was obtained from the top of the deethanizer 2, that is, the first stage, and was partially condensed by a condenser, and the obtained liquid phase component was refluxed to the first stage of the deethanizer 2. 104, which is a fluid (A) containing methane as a main component in the condenser, was extracted, and product ethylene was recovered through the purification system 4 below C2. The recovered ethylene was 37.4 T / H.
From the bottom of the deethanizer 2, 103, which is a fluid (C) mainly composed of hydrocarbons having 3 or more carbon atoms, was extracted. No. 103, together with the condensed components removed when compressed by the cracked gas compressor 1, led to components having 3 or more carbon atoms to the C3 or more component purification system 3 to recover product propylene. The recovered propylene was 37.3 T / H.

(Example 2)
Hereinafter, a description will be given with reference to FIG.
The cracked gas 101 (163 T / H, 35 ° C., 0.15 MPa) is mixed with a fluid 106 (31.6 T / H) containing propylene, which will be described later, and compressed by the cracked gas compressor 1 consisting of five stages to perform heat exchange. Then, the temperature was set to 14 ° C. and 3.5 MPa.

Condensed components (including hydrocarbon components having 5 or more carbon atoms and propylene 3.8 T / H) generated in the process of being compressed by the cracked gas compressor 1 were removed (not shown). Obtained compressed gas 102
Table 2 shows the composition. The obtained compressed gas 102 was introduced into the sixteenth stage from the top of the 39-stage deethanizer 2 and separated into the fluids (A) to (C) in the same manner as in Example 1. The composition of each fluid is listed in Table 4.

  As the fluid (B), 32.4 T / H of the vapor phase component 107 present at the top of the deethanizer 2, that is, the first stage, is a fluid (B) mainly composed of a hydrocarbon having 2 carbon atoms. Extracted as. The remaining gas phase component was partially condensed by the condenser 6 and the obtained liquid phase component was refluxed to the first stage of the deethanizer 2 (108). The distillate vapor 104 obtained through the condenser 6 corresponds to the fluid (A) of the present invention. The fluid (B) 105 having the composition shown in Table 4 extracted from the top of the deethanizer 2 as described above is hydrogenated in a hydrogenation reactor (not shown), and acetylene is converted into ethane or ethylene. And introduced into the reactor 5. In the reactor 5, it is assumed that the catalyst obtained in accordance with Preparation Example 1 of International Publication No. 2010/128644 is used, and the composition of the stream at the inlet and outlet of the reactor 5 is set to Table 5 in RSTOIC mode Simulated. The obtained propylene-rich fluid 106 (31.6 T / H) was mixed with the naphtha cracker cracked gas 101 and introduced into the cracked gas compressor 1 as described above. The power consumption in the cracked gas compressor 1 was 25.3 MW.

A fluid (A) containing methane or hydrogen as a main component in the condenser was extracted as a distillate vapor 104, and product ethylene was recovered through a C2 or lower component purification system 4. The recovered ethylene was 37.7 T / H.
103 was extracted from the bottom of the deethanizer 2, and together with the condensed component produced in the cracked gas compressor 1, a component having 3 or more carbon atoms was recovered through a C 3 or more component purification system 3 and product propylene. The recovered propylene was 37.7 T / H.

(Comparative Example 1)
This will be described with reference to FIG.
The entire amount of the top vapor 107 obtained from the top of the deethanizer 2 is introduced into the condenser 6 and partially condensed, and the obtained liquid phase component is refluxed to the first stage of the deethanizer. (108) was conducted in the same manner as in Example 2 and extracted as distillate vapor (fluid (A)) 104 (composition shown in Table 6) rich in methane in the condenser, of which 77.7 T / H The product ethylene was recovered through a C2 or lower component purification system 4. The recovered ethylene was 37.7 T / H.
36.9 T / H of the gaseous fluid (A) 104 rich in methane was introduced into the reactor 5 after acetylene was converted into ethane / ethylene after hydrogenation in a hydrogenation reactor (not shown). The power consumption in the cracked gas compressor 1 was 27.3 MW.

In Comparative Example 1, as expected, a part of the gas phase component 107 obtained from the condenser 6 of the deethanizer 2 is supplied to the reactor 5, and the obtained reaction mixture is compressed by the cracked gas compressor 1. did. In this case, since there was too much methane and hydrogen contained in the reaction mixture 106, a great load was applied to the cracked gas compressor 1, and the power consumption was 27.3 MW.
In Example 1, the fraction 105 whose main component is a hydrocarbon having 2 carbon atoms was extracted from the seventh stage of the deethanizer 2 and used in the reactor 5. In this case, since methane and hydrogen in the reaction mixture 106 are not main components, the load of the cracked gas compressor 1 was reduced, and the power consumption was 25.4 MW.

In Example 2, a fraction 105 whose main component is a hydrocarbon having 2 carbon atoms was extracted from the first stage of the deethanizer 2 and supplied to the reactor 5. In this case, since methane and hydrogen in the reaction mixture 106 are not the main components, the load of the cracked gas compressor 1 was reduced, and the power consumption was 25.3 MW.

  According to the production method of the present invention, in the production method of propylene using a mixture containing ethylene as a raw material, the amount of methane and hydrocarbon components having 4 or more carbon atoms in the reaction mixture obtained after the reaction can be minimized. Thereby, the load concerning a compressor is reduced, energy cost is reduced, and an efficient manufacturing method can be provided.

DESCRIPTION OF SYMBOLS 1 Cracking gas compressor 2 Deethanizer 3 C3 or more component purification system 4 C2 or less component purification system 5 Reactor 6 Condenser 101 Naphtha cracker cracked gas 102 Compressed gas 103 Fluid mainly containing hydrocarbons having 3 or more carbon atoms ( C)
104 Fluid mainly composed of methane or hydrogen (A)
105 Fluid mainly composed of C2 hydrocarbon (B)
106 Propylene-rich fluid 107 Overhead vapor 108 Reflux

Claims (7)

A method for producing propylene, comprising the following steps (1) to (4).
Step (1): The raw material mixture containing ethylene is converted into a fluid (A) containing methane, hydrogen, and a hydrocarbon having 2 carbons in one distillation column , the main component is a hydrocarbon having 2 carbons, and carbon. Fluid (B) in which the mole percentage of hydrocarbons of number 2 is higher than the mole percentage of hydrocarbons of carbon numbers 2 in fluid (A), and fluid (C) whose main component is hydrocarbon having 3 or more carbon atoms Step (2): introducing the fluid (B) into a reactor and bringing it into contact with a catalyst to obtain a reaction mixture containing propylene,
Step (3): After the reaction mixture is compressed, the reaction mixture is subjected to the step (1) and separated into fluids (A) to (C) together with the raw material mixture containing ethylene. Step (4): The step (1) Purifying the fluid (C) separated in step 1 and separating propylene Further comprising the step of selective hydrogenation of alkynes and dienes, process for producing propylene according to claim 1. The method for producing propylene according to claim 2 , wherein the hydrogenation is performed by a liquid phase reaction. A method for producing propylene, comprising the following steps (0), (1 '), (2'), (3 ') and (4').
Step (0): The raw material mixture containing ethylene, compressed to process step (1 '): wherein obtained in step (0), the compressed material mixture, in a single distillation column, methane, hydrogen, and The fluid (A) containing a hydrocarbon having 2 carbon atoms, the main component being a hydrocarbon having 2 carbon atoms, and the mole percentage of the hydrocarbon having 2 carbon atoms is the same as that of the hydrocarbon having 2 carbon atoms in the fluid (A). The step of separating the fluid (B) having a higher mole percentage and the fluid (C) whose main component is a hydrocarbon having 3 or more carbon atoms Step (2 ′): introducing the fluid (B) into the reactor, Contacting with a catalyst to obtain a reaction mixture comprising propylene,
Step (3 ′): The reaction mixture is subjected to the step (0) and compressed together with the raw material mixture containing ethylene. Step (4 ′): The fluid (C) separated in the step (1 ′) ), And the step of separating propylene A method for producing propylene, comprising the following steps (0), (1 '), (2'), (3 ") and (4 ').
Step (0): The raw material mixture containing ethylene, compressed to process step (1 '): wherein obtained in step (0), the compressed material mixture, in a single distillation column, methane, hydrogen, and The fluid (A) containing a hydrocarbon having 2 carbon atoms, the main component being a hydrocarbon having 2 carbon atoms, and the mole percentage of the hydrocarbon having 2 carbon atoms is the same as that of the hydrocarbon having 2 carbon atoms in the fluid (A). The step of separating the fluid (B) having a higher mole percentage and the fluid (C) whose main component is a hydrocarbon having 3 or more carbon atoms Step (2 ′): introducing the fluid (B) into the reactor, Contacting with a catalyst to obtain a reaction mixture comprising propylene,
Step (3 ''): Step of compressing the reaction mixture, then subjecting it to the step (1 ′) and separating it into fluids (A) to (C) together with the compressed raw material mixture Step (4 ′): A step of purifying the fluid (C) separated in the step (1 ′) and separating propylene. Furthermore, the manufacturing method of the propylene of Claim 4 or 5 including the process of selectively hydrogenating alkynes and dienes. The method for producing propylene according to claim 6 , wherein the hydrogenation is performed by a liquid phase reaction.

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