WO2021193457A1

WO2021193457A1 - Method for producing 1,3-butadiene and device for producing 1,3-butadiene

Info

Publication number: WO2021193457A1
Application number: PCT/JP2021/011461
Authority: WO
Inventors: 宣利柳橋; 悠西山; 昴嗣滝沢; 友樹中間
Original assignee: 積水化学工業株式会社
Priority date: 2020-03-23
Filing date: 2021-03-19
Publication date: 2021-09-30
Also published as: JPWO2021193457A1

Abstract

A method for continuously producing 1,3-butadiene from an ethanol supply source including ethanol, the method comprising a gas regulation step, a conversion step, a purification step, and one or more steps selected from among a recycling step, a trapping step, and a recycle control step.

Description

1,3-Butadiene production method and 1,3-butadiene production equipment

The present invention relates to a method for producing 1,3-butadiene and an apparatus for producing 1,3-butadiene.
The present application claims priority under Japanese Patent Application No. 2020-051408 filed in Japan on March 23, 2020 and Japanese Patent Application No. 2020-051406 filed in Japan on March 23, 2020. The contents are used here.

Butadiene such as 1,3-butadiene is used as a raw material for styrene-butadiene rubber (SBR) and the like. As a method for producing 1,3-butadiene, for example, a method of converting ethanol to acetaldehyde and further converting ethanol and acetaldehyde to 1,3-butadiene in the presence of a catalyst is known (Patent Document 1).

Special Table 2017-532318

However, with the conventional production method, there is room for improvement in the yield of 1,3-butadiene.

An object of the present invention is to provide a method for producing 1,3-butadiene that can continuously produce 1,3-butadiene with a high yield.

The problem is solved by the following means.
[1] A method for continuously producing 1,3-butadiene from an ethanol feedstock containing ethanol, which comprises a gas preparation step of preparing an ethanol-containing gas from the ethanol feedstock and the ethanol-containing gas in the presence of a catalyst. A conversion step of converting ethanol in the gas to 1,3-butadiene, a purification step of purifying the crude gas containing 1,3-butadiene obtained in the conversion step to obtain purified 1,3-butadiene, and recycling. The recycling step includes one or more steps of a step, a trapping step, and a recycling control step, and the recycling step is exhaust gas discharged in the purification step, and is used with one or both of ethanol and acetaldehyde. , At least a part of the vaporized gas obtained by heating at least a part of the exhaust gas containing a high boiling point component having a boiling point higher than that of ethanol and acetaldehyde is transferred to either or both of the gas preparation step and the conversion step. The trapping step is a step of returning, and the trap step is a discharge gas discharged in the purification step, which contains one or both of ethanol and acetaldehyde and a high boiling point component having a boiling point higher than that of ethanol and acetaldehyde. A step of returning at least a part of the high boiling point component removing gas obtained by removing at least a part of the high boiling point component to one or both of the gas preparation step and the conversion step, and the recycling control. The step is the exhaust gas discharged from either one or both of the conversion step and the purification step, and at least a part of the exhaust gas containing either one or both of ethanol and acetaldehyde is used in the gas preparation step and the gas preparation step. It is a step of returning to the step X selected from the conversion step and controlling the molar ratio (ethanol / acetaldehyde) in the gas of the step to 1 to 100, in which a part of the exhaust gas is separated and the rest is the step. A step D1 of returning to X, a step D2 of returning at least a part of the exhaust gas to the step X and separating a part of acetaldehyde from the gas of the step X, and a first step in which ethanol is the main component of the exhaust gas. (1) A method for producing 1,3-butadiene, which comprises a step D3 in which an exhaust gas and a second exhaust gas containing acetaldehyde as a main component are separated and returned to the step X, and at least one selected from the group consisting of the step D3.
[1-1] A method for continuously producing 1,3-butadiene from an ethanol feedstock containing ethanol, which comprises a gas preparation step of preparing an ethanol-containing gas from the ethanol feedstock and the presence of a catalyst. A conversion step of converting ethanol in an ethanol-containing gas to 1,3-butadiene, and a purification step of purifying the crude gas containing 1,3-butadiene obtained in the conversion step to obtain purified 1,3-butadiene. , At least of the vaporized gas obtained by heating at least a part of the exhaust gas containing either or both of ethanol and acetaldehyde and a high boiling point component having a boiling point higher than that of ethanol and acetaldehyde, which is discharged in the purification step. A recycling step in which a part of the gas is returned to one or both of the gas preparation step and the conversion step, or one or both of ethanol and acetaldehyde discharged in the purification step, and a boiling point higher than that of ethanol and acetaldehyde. At least a part of the high boiling point component removing gas obtained by removing at least a part of the high boiling point component from the exhaust gas containing the high boiling point component can be obtained from either one of the gas preparation step and the conversion step or the conversion step. A method for producing 1,3-butadiene, which comprises a trapping step of returning to both.
[2-1] A method for continuously producing 1,3-butadiene from an ethanol feedstock containing ethanol, which comprises a gas preparation step of preparing an ethanol-containing gas from the ethanol feedstock and the presence of a catalyst. A conversion step of converting ethanol in an ethanol-containing gas to 1,3-butadiene, and a purification step of purifying the crude gas containing 1,3-butadiene obtained in the conversion step to obtain purified 1,3-butadiene. At least a part of the exhaust gas containing either one or both of ethanol and acetaldehyde discharged from either one or both of the conversion step and the purification step is returned to at least the gas preparation step or the conversion step. The recycling control step includes a recycling control step of controlling the molar ratio (ethanol / acetaldehyde) in the gas to be subjected to the conversion reaction to 1,3-butadiene from 1 to 100, and the recycling control step separates a part of the exhaust gas. Then, step D1 of returning the balance, step D2 of returning at least a part of the exhaust gas and separating a part of acetaldehyde from the gas of the step of returning the exhaust gas, and ethanol as the main component of the exhaust gas. A method for producing 1,3-butadiene, which comprises a step D3 of separately returning the first exhaust gas and the second exhaust gas containing acetaldehyde as a main component, and at least one selected from the group consisting of.
[1-2] Production of 1,3-butadiene according to [1] or [1-1], wherein the high boiling point component contains either or both of a compound having 6 carbon atoms and a compound having 8 carbon atoms. Method.
[1-3] In the recycling step, when returning at least a part of the vaporized gas to the gas preparation step, at least a part of the high boiling point component in the vaporized gas is removed, and then the gas preparation step. The method for producing 1,3-butadiene according to [1], [1-1] or [1-2].
[1-4] 1 according to [1-3], wherein the total content of the high boiling point component in the exhaust gas is 0.5 to 1% by mass of the total mass of the organic compound in the exhaust gas. , 3-butadiene production method.
[1-5] The 1,3-butadiene according to [1], [1-1] or [1-2], wherein at least a part of the high boiling point component is removed by gas-liquid separation in the trap step. Manufacturing method.
[1-6] The 1 according to [1-5], wherein the total content of the high boiling point component in the exhaust gas is 0.5 to 1% by mass of the total mass of the organic compound in the exhaust gas. , 3-butadiene production method.
[2-2] The step D1, the step D2, and the step D3 based on the result of monitoring the molar ratio (ethanol / acetaldehyde) of either one or both of the gas preparation step and the conversion step with an analyzer. The method for producing 1,3-butadiene according to [1] or [2-1], wherein one or more of them are carried out.
[2-3] When the molar ratio (ethanol / acetaldehyde) becomes 0.8 or less in the monitoring by the analyzer, one or more of the step D1, the step D2, and the step D3 is started. 2-2] The method for producing 1,3-butadiene according to.
[2-4] In the step D2, the gas in the step of returning the exhaust gas is introduced into the separation device, and a part of acetaldehyde is separated in the separation device under a pressure of 1.0 to 5.0 MPa. 1], the method for producing 1,3-butadiene according to any one of [2-1] to [2-3].
[2-5] In the step D3, any one of [1], [2-1] to [2-4], which adjusts the flow rate for returning the first exhaust gas and the flow rate for returning the second exhaust gas, respectively. The method for producing 1,3-butadiene according to. [7] The gas preparation step includes step A1 of vaporizing the ethanol supply raw material into the ethanol-containing gas under the conditions of a pressure of −1.0 to 3.0 MPaG and a temperature of −100 to 400 ° C. [7] 1], the method for producing 1,3-butadiene according to any one of [1-1] to [1-6], [2-1] to [2-5].
[8] The conversion step includes at least step B1 of converting ethanol in the ethanol-containing gas to 1,3-butadiene in the presence of a catalyst under the conditions of a pressure of 0 to 1.0 MPaG and a temperature of 50 to 500 ° C. A step B2 for separating a hydrogen-containing gas from the ethanol-containing gas supplied to the step B1 by gas-liquid separation, and a step B3 for separating a nitrogen-containing gas from the gas after the step B1 by gas-liquid separation. At least one selected from the group consisting of step B4 for separating the gas containing acetaldehyde from the ethanol-containing gas supplied to the step B1 by distillation may be combined with the step B1 [1], [7]. ], [1-1] to [1-6], [2-1] to [2-5]. The method for producing 1,3-butadiene.
[9] The purification step includes a step C1 in which butene in the crude gas is dehydrogenated and converted to 1,3-butadiene, and a step C1 in which the hydrogen gas is separated from the crude gas by gas-liquid separation 1 , 3-butadiene-containing liquid is obtained in step C2, and the liquefaction of the crude gas or the 1,3-butadiene-containing liquid is distilled to separate the ethylene-containing gas, the 1,3-butadiene-containing effluent and the acetaldehyde-containing liquid. [1], [7]. The method for producing 1,3-butadiene according to any one of [8], [1-1] to [1-6], and [2-1] to [2-5].
[10] A production apparatus for continuously producing 1,3-butadiene from an ethanol supply raw material containing ethanol, which is a gas preparation means, a conversion means, a purification means, a recycling means, a trapping means, and a recycling control means. The gas preparing means comprises a vaporizer that vaporizes the ethanol supply raw material into an ethanol-containing gas, and the conversion means comprises ethanol in the ethanol-containing gas. The purification means includes a reactor for converting to 1,3-butadiene, and the purification means is a means for purifying the crude gas containing 1,3-butadiene obtained by the conversion means, and the recycling means is from the purification means. A vaporizer that heats at least a part of the discharged gas containing either one or both of ethanol and acetaldehyde to generate a vaporized gas, and the vaporized gas at least the gas preparing means or the gas preparation means or the above. The trap means includes at least a pipe for returning to the conversion means, and the trap means includes a high boiling point component removing device for removing at least a part of a high boiling point component having a boiling point higher than that of ethanol and acetaldehyde in the exhaust gas discharged from the purification means. The recycling control means is provided with at least a pipe for returning the exhaust gas from which the high boiling point component has been removed to the gas preparation means or the conversion means, and the recycling control means discharges the exhaust gas discharged from either or both of the conversion means and the purification means. A pipe for returning at least a part of the exhaust gas containing one or both of ethanol and acetaldehyde to the means X selected from the gas preparation means and the conversion means, and a pipe downstream of the returned portion. It is equipped with at least an analyzer that analyzes the molar ratio (ethanol / acetaldehyde) in the gas, and further, a first recycling control device that separates a part of the exhaust gas and returns the rest to the means X, and the discharge. A second recycling control device that returns at least a part of the gas to the means X and separates a part of acetaldehyde from the gas of the means X, and a first that returns the first exhaust gas containing ethanol as a main component to the means X. A 1,3-butadiene production device including a third recycling control device including a pipe and a second pipe for returning a second exhaust gas containing acetaldehyde as a main component to the means X, and at least one selected from the group consisting of the pipe and the second pipe. ..
[1-10] A production apparatus for continuously producing 1,3-butadiene from an ethanol supply raw material containing ethanol, which is either a gas preparation means, a conversion means, a purification means, a recycling means, or a trapping means. The gas preparing means includes one or both, and the gas preparing means includes a vaporizer that vaporizes the ethanol supply raw material into an ethanol-containing gas, and the converting means converts ethanol in the ethanol-containing gas into 1,3-butadiene. The purification means is a means for purifying the crude gas containing 1,3-butadiene obtained by the conversion means, and the recycling means is the ethanol discharged from the purification means. And at least a vaporizer that heats at least a part of the exhaust gas containing one or both of acetaldehyde to generate a vaporized gas, and a pipe that returns the vaporized gas to at least the gas preparing means or the converting means. The trap means includes a high-boiling component removing device that removes at least a part of a high-boiling component having a boiling point higher than that of ethanol and acetaldehyde in the exhaust gas discharged from the purification means, and an exhaust gas from which the high-boiling component has been removed. A 1,3-butadiene production apparatus comprising at least a gas preparing means or a pipe for returning to the conversion means.
[1-11] The 1,3-described in [10] or [1-10], wherein in the recycling means, a gas-liquid separator is installed in the middle of a pipe for returning the vaporized gas to the gas preparing means. Butadiene production equipment.
[2-10] A production apparatus for continuously producing 1,3-butadiene from an ethanol supply raw material containing ethanol, which comprises gas preparation means, conversion means, purification means, and recycling control means. The gas preparation means includes a vaporizer that vaporizes the ethanol supply raw material into an ethanol-containing gas, and the conversion means includes a reactor that converts ethanol in the ethanol-containing gas to 1,3-butadiene. The purification means is a means for purifying a crude gas containing 1,3-butadiene obtained by the conversion means, and the recycling control means is discharged from either or both of the conversion means and the purification means. The molar ratio (ethanol / It is equipped with at least an analyzer that analyzes (acetaldehyde), a first recycling control device that separates a part of the exhaust gas and returns the rest, and returns at least a part of the exhaust gas to release the exhaust gas. A second recycling control device that separates a part of acetaldehyde from the gas in the returned process, a first pipe that returns the first exhaust gas containing ethanol as the main component, and a second exhaust gas that returns the second exhaust gas containing acetaldehyde as the main component. A 1,3-butadiene production device comprising a third recycling control device including piping and at least one selected from the group consisting of.

According to the present invention, it is possible to provide a method for producing 1,3-butadiene that can continuously produce 1,3-butadiene with a high yield.

It is the schematic schematic diagram which showed the manufacturing apparatus used in the manufacturing method of 1,3-butadiene of 1st Embodiment. It is the schematic schematic diagram which showed the manufacturing apparatus used in the manufacturing method of 1,3-butadiene of 2nd Embodiment. It is the schematic schematic diagram which showed the manufacturing apparatus used in the manufacturing method of 1,3-butadiene of 4A Embodiment. It is a flowchart of production of 1,3-butadiene using the production apparatus of FIG. It is the schematic schematic diagram which showed the manufacturing apparatus used in the manufacturing method of 1,3-butadiene of 4B Embodiment. It is a flowchart of production of 1,3-butadiene using the production apparatus of FIG.

The numerical range represented by "-" represents the numerical range including the numerical values before and after "-" as the lower limit value and the upper limit value.

The yield of 1,3-butadiene can be improved by recovering and recycling unreacted raw materials (ethanol) and intermediate products (acetaldehyde) in the exhaust gas discharged in the production process of 1,3-butadiene. ..
In addition to unreacted raw materials (ethanol) and intermediate products (acetaldehyde) in the exhaust gas discharged in the production process of 1,3-butadiene, high boiling points having a higher boiling point than by-products (ethanol and acetaldehyde). By recovering and recycling the component), the yield of 1,3-butadiene can be further improved.
Further, when the content of the high boiling point component in the exhaust gas is high, clogging of the piping or the pump can be prevented by removing the high boiling point component.

[Method for producing 1,3-butadiene]
The method for producing 1,3-butadiene of the present embodiment is a method for continuously producing 1,3-butadiene from an ethanol supply raw material containing ethanol. The method for producing 1,3-butadiene of the present embodiment includes the following steps A to D.
Step A: A gas preparation step of preparing an ethanol-containing gas from an ethanol supply raw material.
Step B: A conversion step of converting ethanol in an ethanol-containing gas to 1,3-butadiene in the presence of a catalyst.
Step C: A purification step of purifying the crude gas containing 1,3-butadiene obtained in step B to obtain purified 1,3-butadiene.
Process D: Any one or more of a recycling process, a trap process, and a recycling control process.

The recycling step heats at least a part of the exhaust gas discharged from step C, which contains one or both of ethanol and acetaldehyde and a high boiling point component having a boiling point higher than that of ethanol and acetaldehyde. This is a step of returning at least a part of the vaporized gas thus obtained to one or both of the steps A and B.

In the trap step, the high boiling point component is discharged from the exhaust gas containing one or both of ethanol and acetaldehyde and a high boiling point component having a boiling point higher than that of ethanol and acetaldehyde. This is a step of returning at least a part of the high boiling point component removing gas obtained by removing at least a part of the above step A and step B to one or both of the steps A and B.

The recycling control step is an exhaust gas discharged from either one or both of step B and step C, and is an exhaust gas containing either one or both of ethanol and acetaldehyde (hereinafter, "exhaust gas (E / A)). At least a part of (also referred to as) is returned to step A or step B, and the molar ratio (ethanol / acetaldehyde) in the gas to be subjected to the conversion reaction to 1,3-butadiene (hereinafter, “molar ratio (E / A)”. ) Is also described.) Is a step of controlling from 1 to 100.

<Step A>
Step A includes step A1 in which the ethanol supply raw material is vaporized into an ethanol-containing gas under the conditions of a pressure of −1.0 to 3.0 MPaG and a temperature of −100 to 400 ° C. By combining step A1 with step D described later, heat utilization efficiency can be improved and energy required for vaporization can be suppressed.

The ethanol supply raw material contains ethanol as an essential component, and may contain other components such as water as long as the effects of the present invention are not impaired. The ratio of ethanol in the ethanol supply raw material is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 93% by mass or more, based on the total mass of the ethanol supply raw material. The upper limit of the proportion of ethanol is theoretically 100% by mass.
The ratio of ethanol in the ethanol supply raw material is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, still more preferably 93 to 100% by mass, based on the total mass of the ethanol supply raw material.

The ethanol supply raw material is not particularly limited, and may be, for example, ethanol derived from fossils such as shale gas and petroleum, and bioethanol derived from biomass such as plants, animals and garbage. Of these, bioethanol is preferable because it contains few impurities such as nitrogen compounds, sulfur compounds, and phosphorus compounds, and the catalyst does not easily deteriorate.
The total content of the nitrogen compound, the sulfur compound, and the phosphorus compound with respect to the total mass of the bioethanol is preferably 0 to 0.1% by mass, more preferably 0 to 0.01% by mass.

The pressure at the time of vaporization of the ethanol supply raw material in step A1 may be set in the range of -1.0 to 3.0 MPaG, preferably -0.5 to 2.0 MPaG, and more preferably -0.3 to 1.0 MPaG. preferable. When the pressure at the time of vaporization is equal to or higher than the lower limit of the above range, the volume at the time of vaporization does not become excessive and the size of the mechanical equipment can be suppressed. If the pressure at the time of vaporization is equal to or less than the upper limit of the above range, it is efficiently vaporized.

The temperature at the time of vaporization of the ethanol supply raw material in step A1 may be set in the range of -100 to 400 ° C, preferably 0 to 200 ° C, and more preferably 25 to 100 ° C. If the temperature at the time of vaporization is equal to or higher than the lower limit of the above range, it is efficiently vaporized. If the temperature at the time of vaporization is not more than the upper limit of the above range, excessive heating becomes unnecessary.

In step A, if necessary, one or more kinds of gases are mixed with the ethanol-containing gas obtained in step A1 to adjust the concentration of ethanol in the ethanol-containing gas within the range of 0.1 to 100% by volume. A2 may be further included.

The ethanol concentration of the ethanol-containing gas may be adjusted in the range of 0.1 to 100% by volume, preferably 10 to 100% by volume, and more preferably 20 to 100% by volume. When the ethanol concentration is equal to or higher than the lower limit of the above range, the yield of 1,3-butadiene is improved.

As the gas to be mixed with the ethanol-containing gas (diluting gas), a gas that does not adversely affect the conversion reaction from ethanol to 1,3-butadiene can be used, and examples thereof include rare gases such as nitrogen gas and argon gas. .. Of these, nitrogen gas and argon gas are preferable from the viewpoint of price and availability. As the gas to be mixed with the ethanol-containing gas, only one type may be used alone, or two or more types may be used in combination.

<Process B>
In step B, as the conversion reaction from ethanol to 1,3-butadiene, a one-step reaction represented by the following formula (1) may be adopted, and is represented by the following formulas (2) and (3). A two-stage reaction may be adopted. This embodiment is particularly effective when a two-step reaction is adopted in step B.
2CH ₃ CH ₂ OH → CH ₂ = CH-CH = CH ₂ + 2H ₂ O + H ₂ ... (1)
CH ₃ CH ₂ OH → CH ₃ CHO + H ₂ ... (2)
CH ₃ CH ₂ OH + CH ₃ CHO → CH ₂ = CH-CH = CH ₂ + 2H ₂ O ... (3)

In step B, two or more parallel reactors may be used for at least a part of the conversion reaction of converting ethanol in the ethanol-containing gas to 1,3-butadiene in the presence of a catalyst. For example, in the case of a one-stage reaction, ethanol may be converted to 1,3-butadiene in two or more parallel reactors. In the case of a two-stage reaction, two or more parallel reactors may be used for either or both of the first-stage conversion reaction and the second-stage conversion reaction. In terms of improving the yield of 1,3-butadiene, it is preferable to use two or more parallel reactors for both the first-stage conversion reaction and the second-stage conversion reaction.
The number of reactors installed in parallel in step B can be appropriately set, and can be, for example, 2 to 5.

Step B preferably includes at least the following step B1. By combining step B1 with step D described later, the raw material utilization rate is increased and the yield of 1,3-butadiene is improved.
Step B1: Ethanol in the ethanol-containing gas is converted to 1,3-butadiene in the presence of a catalyst under the conditions of a pressure of 0 to 1.0 MPaG and a temperature of 50 to 500 ° C.

Step B1 of the two-step reaction includes, for example, the following steps B11 and B12.
Step B11: A part of ethanol in the ethanol-containing gas obtained in Step A is converted to acetaldehyde in the presence of the first catalyst under the conditions of a pressure of 0 to 1.0 MPaG and a temperature of 50 to 500 ° C.
Step B12: The intermediate gas containing unreacted ethanol and acetaldehyde obtained in Step B11 is mixed with ethanol and acetaldehyde in the presence of a second catalyst under the conditions of a pressure of 0 to 1.0 MPaG and a temperature of 50 to 500 ° C. Convert to 3-butadiene.

In step B11, in the presence of the first catalyst, a part of ethanol in the ethanol-containing gas supplied from step A is converted to acetaldehyde. This produces an intermediate gas containing ethanol and acetaldehyde.

The first catalyst may be any catalyst that promotes the conversion reaction from ethanol to acetaldehyde, and examples thereof include a mixture of chromium oxide and copper oxide, zinc oxide, and a mixture of copper oxide and silicon oxide. Of these, a mixture of copper oxide and silicon oxide is preferable from the viewpoint of conversion rate to acetaldehyde. As the first catalyst, one type may be used alone, or two or more types may be used in combination.

The pressure during the conversion reaction in step B11 may be set in the range of 0 to 1.0 MPaG, preferably 0 to 0.5 MPaG, and more preferably 0 to 0.3 MPaG. When the pressure in step B11 is equal to or higher than the lower limit of the above range, the conversion rate to acetaldehyde is improved. When the pressure in step B11 is equal to or less than the upper limit of the above range, liquefaction during the reaction can be suppressed.

The temperature at the time of the conversion reaction in step B11 may be set in the range of 50 to 500 ° C, preferably 200 to 500 ° C, and more preferably 250 to 350 ° C. When the temperature in step B11 is equal to or higher than the lower limit of the above range, the conversion rate to acetaldehyde is improved. When the temperature in step B11 is equal to or less than the upper limit of the above range, excessive energy consumption can be suppressed.

The conversion rate from ethanol to acetaldehyde in step B11 is preferably 30 to 70%.
The "conversion rate to aldehyde" in step B11 is the number of moles of ethanol consumed in the reactor per unit time with respect to the number of moles of ethanol in the ethanol-containing gas supplied to the reactor in step B11 per unit time. It means the ratio of the number of moles (percentage). The number of moles of ethanol consumed in the reactor of step B11 per unit time is determined from the number of moles of ethanol in the ethanol-containing gas supplied to the reactor of step B11 per unit time from the reactor of step B11. It is calculated by subtracting the number of moles of ethanol in the discharged intermediate gas per unit time.

The selectivity of acetaldehyde in the conversion reaction of step B11 is preferably 85% or more, more preferably 90% or more. The upper limit of the selectivity of acetaldehyde is not particularly limited, but is preferably 100% or less, for example. When it is less than 100%, if the by-product is diethyl ether or ethylene, it can be separated and converted to ethanol, which is preferable. The "acetaldehyde selectivity" in step B11 is the ratio (percentage) of the number of moles of ethanol converted to acetaldehyde per unit time to the number of moles of ethanol consumed in the reactor of step B11 per unit time. Means.
As by-products that can be contained in the intermediate gas obtained in step B11, crotonaldehyde (CH ₃ CH = CHCHO), butyraldehyde (CH ₃ CH ₂ CH ₂ CHO), ethyl acetate (CH ₃ COOCH ₂ CH ₃ ), acetic acid (CH ₃ COOH) and the like. Further, in addition to these by-products, one or both of a compound having 6 carbon atoms (C6 component) and a compound having 8 carbon atoms (C8 component) may be produced.

In step B12, ethanol and acetaldehyde in the intermediate gas supplied from step B11 are converted to 1,3-butadiene in the presence of the second catalyst. As a result, a crude gas containing 1,3-butadiene is generated.

The second catalyst may be any catalyst that promotes the conversion reaction of ethanol and acetaldehyde to 1,3-butadiene, and examples thereof include tantalum, zirconium, niobium, hafnium, magnesium, zinc, silicon, and cerium. Of these, hafnium is preferable from the viewpoint of the yield of 1,3-butadiene. As the second catalyst, one type may be used alone, or two or more types may be used in combination.
Examples of the mode in which the second catalyst is used include, for example, metals, oxides, and chlorides, and examples thereof include a mode in which the second catalyst is supported on a carrier and used, and a mode in which the second catalyst is used as a mixture of two or more kinds.

The pressure during the conversion reaction in step B12 may be set in the range of 0 to 1.0 MPaG, preferably 0 to 0.5 MPaG, and more preferably 0 to 0.3 MPaG. When the pressure in step B12 is equal to or higher than the lower limit of the above range, the yield of 1,3-butadiene is improved. When the pressure in step B12 is not more than the upper limit of the above range, the decrease in yield of 1,3-butadiene due to the excessive reaction can be suppressed.

The temperature at the time of the conversion reaction in step B12 may be set in the range of 50 to 500 ° C., preferably 300 to 400 ° C., more preferably 320 to 370 ° C. When the temperature in step B12 is equal to or higher than the lower limit of the above range, the yield of 1,3-butadiene is improved. When the temperature in step B12 is not more than the upper limit of the above range, the decrease in yield of 1,3-butadiene due to the excessive reaction can be suppressed.

The conversion rate of ethanol and acetaldehyde to 1,3-butadiene in step B12 is preferably more than 30%, more preferably more than 40%, still more preferably more than 50%. The upper limit of the conversion rate to 1,3-butadiene is not particularly limited, but may be, for example, 100% or less, 95% or less, or 90% or less. When the conversion rate is less than 100%, unreacted ethanol and acetaldehyde may be separated and recovered and reused. The conversion rate to 1,3-butadiene is preferably more than 30% and 100% or less, more preferably more than 40% and 100% or less, and further preferably more than 50% and 100% or less.
The “conversion rate to 1,3-butadiene” in step B12 is consumed in the reactor with respect to the number of moles of ethanol and acetaldehyde in the intermediate gas supplied to the reactor in step B12 per unit time. It means the molar ratio of the number of moles of ethanol and acetaldehyde per unit time. The number of moles of ethanol and acetaldehyde consumed in the reactor of step B12 per unit time is determined from the number of moles of ethanol and acetaldehyde in the intermediate gas supplied to the reactor of step B12 per unit time. It is calculated by subtracting the number of moles of ethanol and acetaldehyde in the crude gas discharged from the reactor per unit time.

The selectivity of 1,3-butadiene in the conversion reaction of step B12 is preferably more than 60%, more preferably more than 70%, still more preferably more than 80%. The upper limit of the selectivity of 1,3-butadiene is not particularly limited, but may be 100% or less, for example. If it is less than 100%, diethyl ether and ethylene as by-products can be converted to ethanol, and crotyl alcohol and crotonaldehyde can be converted to 1,3-butadiene, which is preferable. The selectivity of 1,3-butadiene is preferably more than 60% and 100% or less, more preferably more than 70% and 100% or less, and further preferably more than 80% and 100% or less. The “1,3-butadiene selectivity” of step B12 is the ethanol and acetaldehyde converted to 1,3-butadiene with respect to the number of moles of ethanol and acetaldehyde consumed in the reactor of step B12 per unit time. Means the ratio (percentage) of the number of moles per unit time of.

In step B12, it is preferable that 65 to 80 mol% is converted to 1,3-butadiene with respect to the number of moles of acetaldehyde in the intermediate gas supplied from step B11 per unit time. In step B12, in addition to ethanol in the intermediate gas supplied from step B11, it is preferable that 65 to 80 mol% is converted to 1,3-butadiene with respect to the number of moles per hour.
The by-product which may be contained in the crude product gas obtained in step B12, ethylene _{_{(H 2 C = CH 2)}} , propylene _{_{(H 2 C = CHCH 3)}} , diethyl ether _{_{_{_{(CH 3 CH 2 OCH 2 CH}}}} 3), Acetic acid (CH ₃ COOH), Ethyl acetate (CH ₃ COOCH ₂ CH ₃ ), Butanol (C ₄ H ₉ OH), Butylic acid (CH ₃ CH ₂ CH ₂ COOH), Crotonic acid (CH ₃ CH = CH COOH), Hexanol (CH 3 CH = CH COOH) C ₆ H ₁₃ OH), 1-butene (H ₂ C = CH CH ₂ _{CH 3} ), 2-butene (CH ₃ CH = _{CH CH 3} ), isobutene (H ₂ C = C (CH ₃ ) ₂ ), crotonaldehyde, Crotyl alcohol, penten, pentadiene, hexene, hexadiene, octene, octadiene, hexenoic acid, octene acid, 2,4-dimethylfuran, 2-methyl-2-cyclopentene-1-one, 2,5-diethylphenol, 1, Examples thereof include 2,3-trimethylinden, 4-hydroxy-4-methyl-2-pentanone, and diethylacetal. Further, in addition to these by-products, one or both of a compound having 6 carbon atoms (C6 component) and a compound having 8 carbon atoms (C8 component) may be produced.

Step B of the one-step reaction includes, for example, the following step B13.
Step B13: The ethanol-containing gas obtained in Step A is converted to 1,3-butadiene in the presence of a third catalyst under the conditions of a pressure of 0 to 1.0 MPaG and a temperature of 50 to 500 ° C.

In step B13, in the presence of the third catalyst, ethanol in the ethanol-containing gas supplied from step A is converted to 1,3-butadiene. As a result, a crude gas containing 1,3-butadiene is generated.

The third catalyst may be any one that promotes the conversion reaction from ethanol to 1,3-butadiene, for example, copper oxide, zinc oxide, magnesium oxide, germanium oxide, tantalum oxide, zirconium oxide, hafnium oxide, and oxidation. Examples thereof include niobium, lanthanum oxide, cerium oxide, aluminum oxide, and silicon oxide. Of these, hafnium oxide is preferable from the viewpoint of the yield of 1,3-butadiene. As the third catalyst, one type may be used alone, or two or more types may be used in combination.

The pressure during the conversion reaction in step B13 may be set in the range of 0 to 1.0 MPaG, preferably 0 to 0.5 MPaG, and more preferably 0 to 0.3 MPaG. When the pressure in step B13 is equal to or higher than the lower limit of the above range, the yield of 1,3-butadiene is improved. When the pressure in step B13 is not more than the upper limit of the above range, the decrease in yield of 1,3-butadiene due to the excessive reaction can be suppressed.

The temperature at the time of the conversion reaction in step B13 may be set in the range of 50 to 500 ° C, preferably 250 to 450 ° C, and more preferably 300 to 400 ° C. When the temperature in step B13 is equal to or higher than the lower limit of the above range, the yield of 1,3-butadiene is improved. When the temperature in step B13 is not more than the upper limit of the above range, the decrease in yield of 1,3-butadiene due to the excessive reaction can be suppressed.

The conversion rate from ethanol to 1,3-butadiene in step B13 is preferably more than 30%, more preferably more than 40%, still more preferably more than 50%. The upper limit of the conversion rate to 1,3-butadiene is not particularly limited, but may be, for example, 100% or less, 95% or less, or 90% or less. The conversion rate to 1,3-butadiene is preferably more than 30% and 100% or less, more preferably more than 40% and 100% or less, and further preferably more than 50% and 100% or less.
The “conversion rate to 1,3-butadiene” in step B13 is the ethanol consumed in the reactor with respect to the number of moles of ethanol in the ethanol-containing gas supplied to the reactor in step B13 per unit time. Means the ratio (percentage) of the number of moles per unit time.
The number of moles of ethanol consumed in the reactor of step B13 per unit time is determined from the number of moles of ethanol in the ethanol-containing gas supplied to the reactor of step B13 per unit time from the reactor of step B13. It is calculated by subtracting the number of moles of ethanol in the discharged crude gas per unit time.

The selectivity of 1,3-butadiene in the conversion reaction of step B13 is preferably more than 50%, more preferably more than 60%, and even more preferably more than 70%. The upper limit of the selectivity of 1,3-butadiene is not particularly limited, but may be 100% or less, for example. If it is less than 100%, diethyl ether and ethylene as by-products can be separated and converted to ethanol, and crotyl alcohol and crotonaldehyde can be converted to butadiene, which is preferable. The selectivity of 1,3-butadiene is preferably more than 50% and 100% or less, more preferably more than 60% and 100% or less, and further preferably more than 70% and 100% or less. The “1,3-butadiene selectivity” of step B13 is the number of moles of ethanol consumed in the reactor of step B13 per unit time of ethanol converted to 1,3-butadiene. Means the ratio (percentage) of the number of moles of.

The by-product which may be contained in the crude product gas obtained in step B13, acetaldehyde _(CH 3 CHO), ethylene _{_{(H 2 C = CH 2)}} , propylene _{_{(H 2 C = CHCH 3)}} , diethyl ether _(CH 3 CH ₂ OCH ₂ CH ₃ ), acetic acid (CH ₃ COOH), ethyl acetate (CH ₃ COOCH ₂ CH ₃ ), butanol (C ₄ H ₉ OH), butylic acid (CH ₃ CH ₂ CH ₂ COOH), crotonic acid (CH ₃₎ CH = CHCOOH), Hexanol (C ₆ H ₁₃ OH), 1-Butene (H ₂ C = CH CH ₂ _{CH 3} ), 2-Butene (CH ₃ CH = _{CH CH 3} ), Isobutene (H ₂ C = C (CH ₃₎₎ ) ₂ ), Crotonaldehyde, crotyl alcohol, penten, pentadiene, hexene, hexadiene, octene, octadiene, hexenoic acid, octenoic acid, 2,4-dimethylfuran, 2-methyl-2-cyclopentene-1-one, 2, Examples thereof include 5-diethylphenol, 1,2,3-trimethylinden, 4-hydroxy-4-methyl-2-pentanone and diethylacetal. Further, in addition to these by-products, one or both of a compound having 6 carbon atoms (C6 component) and a compound having 8 carbon atoms (C8 component) may be produced.

In the step B, at least one selected from the group consisting of the following steps B2 to B4 may be combined with the step B1. By combining these steps B2 to B4 with the step D described later, an excessive increase in the amount of gas in the system can be suppressed, and the operating cost can be suppressed.
Step B2: The hydrogen-containing gas is separated from the ethanol-containing gas supplied to step B1 by gas-liquid separation.
Step B3: The gas containing nitrogen is separated from the gas after step B1 by gas-liquid separation.
Step B4: The gas containing acetaldehyde is separated from the ethanol-containing gas supplied to step B1 by distillation.

In step B2, gas-liquid separation is performed on the ethanol-containing gas supplied to step B1 obtained in step A, and the gas containing hydrogen is separated. As a result, side reactions due to reduction are suppressed and the yield of 1,3-butadiene is improved.
The conditions for gas-liquid separation in step B2 are preferably a pressure of 0 to 5 MPaG and a temperature of −150 to 100 ° C.

In step B3, gas-liquid separation is performed on the gas after step B1 to separate the gas containing nitrogen. As a result, an excessive increase in the amount of gas in the system can be suppressed, and the operating cost can be suppressed.
The conditions for gas-liquid separation in step B3 are preferably a pressure of 0 to 5 MPaG and a temperature of −150 to 100 ° C.

In step B4, the ethanol-containing gas supplied to step B1 obtained in step A is supplied to the distillation column for distillation, and the gas containing acetaldehyde is separated. More specifically, for example, a shelf-type distillation column or a filling distillation column is used to extract a gas containing acetaldehyde from the top of the column and an ethanol-containing gas from the intermediate portion.

<Process C>
Step C includes at least one selected from the group consisting of the following steps C1 to C4.
By combining these steps with step D described later, the unreacted product is recycled, the raw material utilization rate is increased, and the yield of 1,3-butadiene is improved.
Step C1: Butene (1-butene, 2-butene, isobutene) in the crude gas is dehydrogenated and converted to 1,3-butadiene.
Step C2: Hydrogen gas is separated from the crude gas by gas-liquid separation to obtain a 1,3-butadiene-containing liquid.
Step C3: The liquefied crude gas or the 1,3-butadiene-containing liquid is distilled to separate it into an ethylene-containing gas, a 1,3-butadiene-containing effluent and an acetaldehyde-containing liquid.
Step C4: The acetaldehyde-containing liquid is distilled and separated into an acetaldehyde-containing gas and a residual liquid containing water.

It is difficult to separate 1-butene, 2-butene, and isobutene from 1,3-butadiene by distillation or the like. In step C1, the ratio of 1,3-butadiene is increased by dehydrogenating 1-butene, 2-butene, and isobutene to convert them to 1,3-butadiene.

When both the step C1 and the step C3 are performed in the step C, the step C1 may be performed before the step C3, or the step C1 may be performed after the step C3.
In step C1, for example, the crude gas obtained in step B or the 1,3-butadiene-containing effluent obtained in step C3 is supplied to the third reactor, and the pressure is -1 in the presence of the fourth catalyst. Under the conditions of 0 to 1.0 MPaG and a temperature of 200 to 550 ° C., 1-butene, 2-butene and isobutene are dehydrogenated to be converted to 1,3-butadiene.
As the mode of the third reactor in the step C1, the same mode as that illustrated in the first reactor described later can be exemplified.

The fourth catalyst may be any catalyst that promotes the dehydrogenation reaction of 1-butene, 2-butene, and isobutene, and examples thereof include molybdenum, tungsten, bismuth, tin, iron, and nickel. Of these, molybdenum is preferable from the viewpoint of the yield of 1,3-butadiene. Examples of the mode in which the fourth catalyst is used include metals, oxides, and chlorides, in which the fourth catalyst is supported on a carrier and used, and in which the elements exemplified on the carrier are supported and used. Alternatively, an embodiment in which a composite oxide containing the exemplified elements is used as a mixture of two or more kinds can be exemplified. As the fourth catalyst, one type may be used alone, or two or more types may be used in combination.

The pressure during the dehydrogenation reaction in step C1 may be set in the range of -1.0 to 1.0 MPaG, preferably -0.5 to 0.5 MPaG, and more preferably -0.3 to 0.3 MPaG. ..
When the pressure in step C1 is equal to or higher than the lower limit of the above range, the yield of 1,3-butadiene is improved. When the pressure in step C1 is not more than the upper limit of the above range, the decrease in yield of 1,3-butadiene due to the excessive reaction can be suppressed.

The temperature at the time of the dehydrogenation reaction in step C1 may be set in the range of 200 to 550 ° C, preferably 300 to 500 ° C, and more preferably 300 to 450 ° C. When the temperature in step C1 is equal to or higher than the lower limit of the above range, the yield of 1,3-butadiene is improved. When the temperature in step C1 is not more than the upper limit of the above range, the decrease in yield of 1,3-butadiene due to the excessive reaction can be suppressed.

In step C2, gas-liquid separation is performed on the crude gas obtained in step B or the crude gas obtained after performing step C1, and hydrogen gas is separated to obtain a 1,3-butadiene-containing liquid. When the ethanol-containing gas is diluted with a dilution gas such as nitrogen gas in step A2, the dilution gas is separated together with the hydrogen gas in step C2.
The conditions for gas-liquid separation of the crude gas are preferably a pressure of 0 to 1.0 MPaG and a temperature of 0 to 100 ° C.

In step C3, the liquefied crude gas obtained in step B, the liquefied crude gas after step C1, or the 1,3-butadiene-containing liquid after step C2 is supplied to the distillation column for distillation. As a result, the ethylene-containing gas, the 1,3-butadiene-containing effluent, and the acetaldehyde-containing liquid are separated. More specifically, for example, using a shelf-type distillation column or a filling distillation column, ethylene-containing gas is extracted from the top of the column, acetaldehyde-containing liquid is extracted from the bottom of the column, and 1,3-butadiene-containing effluent is extracted from the intermediate portion. Extract. In step C3, two distillation columns are used, the ethylene-containing gas is separated in the first distillation column, and the 1,3-butadiene-containing effluent and the acetaldehyde-containing liquid are separated in the second distillation column. May be good.

In addition to ethylene, the ethylene-containing gas contains compounds having 2 to 3 carbon atoms (C2 component, C3 component) such as propylene, methane, and ethane. When the liquefied crude gas obtained in step B is distilled without performing step C1, the diluting gas such as hydrogen gas and nitrogen gas is separated together with the ethylene-containing gas in step C3.
The acetaldehyde-containing liquid includes ethanol, water and the like in addition to acetaldehyde.
The aldehyde-containing liquid may further contain a compound having 6 carbon atoms (C6 component) and a compound having 8 carbon atoms (C8 component).

When step C3 is performed without performing step C2, hydrogen gas is separated together with ethylene-containing gas in step C3. When the ethanol-containing gas is diluted with a dilution gas such as nitrogen gas in step A2, the dilution gas is separated together with the ethylene-containing gas in step C3.

In step C4, the acetaldehyde-containing liquid obtained in step C3 is supplied to the distillation column and separated into an acetaldehyde-containing gas and a residual liquid containing water.
When the step C3 and the step C4 are performed in the step C, the mode is not limited to the mode in which the step C3 and the step C4 are performed separately, and the step C3 and the step C4 may be performed at the same time in one distillation column.

The content of acetaldehyde with respect to the total volume of the acetaldehyde-containing gas obtained in step C4 is preferably 10% by volume or more, more preferably 20% by volume or more, still more preferably 40% by volume or more. The upper limit of the acetaldehyde content with respect to the total volume of the acetaldehyde-containing gas is not particularly limited, but may be, for example, 100% by volume or less, 90% by volume or less, or 80% by volume or less. The content of acetaldehyde with respect to the total volume of the acetaldehyde-containing gas is preferably 10 to 100% by volume, more preferably 20 to 100% by volume, still more preferably 40 to 100% by volume.
The purity of the purified 1,3-butadiene obtained in step C is preferably 95.0% by mass or more, preferably 99.0% by mass, based on the total mass of the 1,3-butadiene-containing liquid or the 1,3-butadiene-containing effluent. More preferably, it is 99.5% by mass or more, and further preferably 99.5% by mass or more. The upper limit of the purity of the purified 1,3-butadiene is not particularly limited, but may be, for example, 100% by mass or less. The purity of the purified 1,3-butadiene is preferably 95.0 to 100% by mass, more preferably 99.0 to 100% by mass, still more preferably 99.5 to 100% by mass.

<Process D>
<< Recycling process >>
In the recycling process, at least one of the exhaust gases emitted from step C4 on the production line, which contains either or both of ethanol and acetaldehyde and a high boiling point component having a boiling point higher than that of ethanol and acetaldehyde. At least a part of the vaporized gas obtained by heating the portion is returned to one or both of step A and step B.
In the exhaust gas discharged from step C on the production line, in addition to the unreacted raw material (ethanol) and intermediate product (acetaldehyde), as a by-product, the number of carbon atoms is 6 which is a component having a boiling point higher than these. Compound (C6 component) and a compound having 8 carbon atoms (C8 component) are included. If the total content of high boiling point components such as C6 component and C8 component in the exhaust gas is 0.5% by mass or more of the total mass of the organic compounds in the exhaust gas, it will be liquefied due to the decrease in temperature, and the pipes and pipes will be liquefied. It tends to cause the pump to block.
Therefore, the content of the high boiling point component in the exhaust gas is monitored on the pipe exiting from the C4 step, and based on the analysis result, it is determined whether to flow the exhaust gas to the recycling step or the trapping step. That is, if the high boiling point component is less than 0.5% by mass of the total mass of the organic compounds in the exhaust gas, the exhaust gas is sent to the recycling step, and if it is 5% by mass or more, the exhaust gas is sent to the trap step.
When the high boiling point component in the total mass of the organic compound in the exhaust gas is monitored and it is less than 0.5% by mass, the temperature is raised to a temperature at which the C6 component and the C8 component are sufficiently vaporized by heating the exhaust gas. It is warmed to vaporize gas, and the vaporized gas is returned to either or both of step A and step B while preventing the precipitation of C6 component and C8 component.
By recycling the unreacted raw material (ethanol) and the intermediate product (acetaldehyde) as raw materials for producing 1,3-butadiene, the yield of 1,3-butadiene is improved. Further, by recycling the C6 component and the C8 component as raw materials for producing 1,3-butadiene, the yield of 1,3-butadiene is further improved.

In the recycling step, after vaporizing the high boiling point component in the exhaust gas discharged from the step C4, it may be returned to the step A or the step B. In the recycling step of step D, it is preferable to return the exhaust gas discharged from step C4 to step B, more preferably to step B1, and step B11 because the effect of improving the yield of 1,3-butadiene is high. It is more preferable to return between the step B12 and the step B12.

In the recycling process, for example, unreacted ethanol or the like is provided by providing a pipe connecting the exhaust gas discharging part in the process C4 on the production line and the part for returning the exhaust gas in the process A or B on the production line. It can be returned to the production line.

In the recycling process, the high boiling point components in the exhaust gas from process C4 are vaporized. As the heat source of the vaporizer, for example, the thermal energy of the crude gas produced in step B may be used.

In step D, when the vaporized gas is returned to step A, the high boiling point component in the vaporized gas may be removed by gas-liquid separation and then returned to step A.

<< Trap process >>
In the trap step, the exhaust gas discharged from step C on the production line, which contains one or both of ethanol and acetaldehyde and a high boiling point component having a boiling point higher than that of ethanol and acetaldehyde, is described as described above. At least a part of the high boiling point component removing gas obtained by removing at least a part of the high boiling point component is returned to one or both of the gas preparation step and the conversion step.
In the exhaust gas discharged from step C on the production line, in addition to the unreacted raw material (ethanol) and intermediate product (acetaldehyde), as a by-product, the number of carbon atoms is 6 which is a component having a boiling point higher than these. Compound (C6 component) and a compound having 8 carbon atoms (C8 component) are included.
When the content of these high boiling point components in the exhaust gas is as high as 0.5% by mass or more of the total mass of the organic compounds in the exhaust gas, they are liquefied due to pressure loss or temperature drop, and are used in piping and pipes. It tends to accumulate in the pump and block it, or increase the operating cost of the equipment. Therefore, by returning at least a part of the high boiling point component removing gas obtained by removing at least a part of the high boiling point component from the exhaust gas to either one or both of step A and step B, the piping or The yield of 1,3-butadiene can be improved while preventing pump blockage or increased equipment operating costs.
Specifically, as a result of monitoring the high boiling point components in the exhaust gas, when the total content of the high boiling point components in the exhaust gas is 0.5% or more of the total mass of the organic compounds in the exhaust gas, Since a part of C6 component and C8 component is condensed in the exhaust gas, the C6 component and C8 component are separated into gas and liquid by heating the exhaust gas to sufficiently vaporize the C6 component and C8 component and then cooling the gas. Then, it is preferable to remove the C6 component and the C8 component which have become liquid components, and return the high boiling point component removing gas to either one or both of the steps A and B.
Further, when the content of the high boiling point component in the exhaust gas becomes high, at least a part of the high boiling point component may be removed and then supplied to the vaporizer. Means for removing at least a part of the high boiling point component include a filter, a gas-liquid separator, and the like.

<< Recycling control process >>
In the recycling control step, the exhaust gas (E / A) discharged from at least one of step B and step C on the production line is returned to at least one of step A and step B on the production line, and 1,3-butadiene. The molar ratio (E / A) in the gas to be subjected to the conversion reaction to is controlled to 1 to 100. This improves the yield of 1,3-butadiene.

The range of the molar ratio (E / A) controlled by the recycling control step is preferably 1 to 50, more preferably 1 to 20, further preferably 1 to 10, 1 to 5, and most preferably 1.1 to 3. When the molar ratio (E / A) is within the above range, the yield of 1,3-butadiene is improved.

In the recycling control step, the exhaust gas (E / A) discharged from the step C may be returned to the step A, or the exhaust gas (E / A) discharged from the step C may be returned to the step B. The exhaust gas (E / A) discharged from B may be returned to step A, the exhaust gas (E / A) discharged from step B may be returned to step B, or these may be combined. .. In step D, it is preferable to return the exhaust gas (E / A) discharged from step C to step B, and more preferably to step B1 because the effect of improving the yield of 1,3-butadiene is high. It is more preferable to return between the step B11 and the step B12. The configuration in which the exhaust gas (E / A) discharged from the process C is returned to the process A or the process B may be combined with the configuration in which the exhaust gas (E / A) discharged from the process B is returned to the process C. ..

When returning the exhaust gas (E / A) to the step B1 that employs the two-stage reaction, the exhaust gas (E / A) may be returned to the step B11 or the exhaust gas (E / A) may be returned to the step B12. It is often preferable to return the exhaust gas (E / A) to step B12.

In the recycling control process, for example, an emission part of the exhaust gas (E / A) in the process B or C on the production line and a part for returning the exhaust gas (E / A) of the process A or B on the production line. By providing a pipe connecting the two, the exhaust gas (E / A) can be returned to the production line.
The molar ratio (E / A) in the gas to be subjected to the conversion reaction to 1,3-butadiene can be analyzed by installing an analyzer such as a process mass spectrometer, for example.

In the recycling control step, in order to control the molar ratio (E / A) in the gas to be subjected to the conversion reaction to 1,3-butadiene from 1 to 100, at least selected from the group consisting of the following steps D1 to D3. Do one. In addition, one or more of step D1, step D2, and step D3 shall be carried out based on the result of monitoring the molar ratio (E / A) of either one or both of step A and step B with an analyzer. Is preferable.
Hereinafter, process A or process B are collectively referred to as process X.
Step D1: A part of the exhaust gas (E / A) is separated, and the rest is returned to the step X.
Step D2: At least a part of the exhaust gas (E / A) is returned to the step X, and a part of acetaldehyde is separated from the gas of the step in which the exhaust gas (E / A) is returned.
Step D3: As the exhaust gas (E / A), the first exhaust gas containing ethanol as a main component and the second exhaust gas containing acetaldehyde as a main component are separated and returned to step X.

In step D1, for example, a branch pipe that branches from the pipe that returns the exhaust gas (E / A) to step X is provided, and a flow rate indicator controller is provided in the branch pipe. Then, based on the analysis result of the molar ratio (E / A) by the analyzer, a part of the exhaust gas (E / A) is separated, and the flow rate for returning the exhaust gas (E / A) to the step X is adjusted. The molar ratio (E / A) is controlled by. For example, if the analyzer shows a decrease in the molar ratio (E / A), it is considered that the ratio of acetaldehyde in the exhaust gas (E / A) is high. Therefore, in this case, the amount of the exhaust gas (E / A) separated into the branch pipe by the flow rate indicator controller is increased, and the flow rate of the exhaust gas (E / A) returned to the step X is decreased.

In step D2, for example, a separation device is provided in the step of returning the exhaust gas (E / A) to the step X, and the molar ratio (E / A) by the analyzer is returned while returning at least a part of the exhaust gas (E / A) through the pipe. Based on the analysis result of A), a part of acetaldehyde is separated from the gas of the step. More specifically, when a decrease in the molar ratio (E / A) is observed in the process of returning the exhaust gas (E / A), acetaldehyde in the gas is separated by a separator to separate the molar ratio (E / A). / A) is increased.

The separation device used in step D2 may be any device capable of separating acetaldehyde, and examples thereof include a gas-liquid separator, a distillation column, and a scrubber. As the separation device in step D2, one type may be used alone, or two or more types may be combined.

In step D2, it is preferable to introduce the gas of the step in which the exhaust gas (E / A) has been returned into the separation device and separate a part of acetaldehyde under a pressure of 1.0 to 5.0 MPa in the separation device. This increases the separation efficiency of acetaldehyde.
The pressure for separating acetaldehyde with the separation device in step D2 is preferably 1.0 to 3.0 MPa, more preferably 1.0 to 2.0 MPa.

In step D3, for example, a first pipe for returning the first exhaust gas containing ethanol as a main component to step X and a second pipe for returning the second exhaust gas containing acetaldehyde as a main component to step X are separately provided. Based on the analysis result of the molar ratio (E / A) by the analyzer, the first exhaust gas and the second exhaust gas are returned to the step X, respectively. In the present invention, "the first exhaust gas contains ethanol as a main component" means that the ratio of ethanol in the first exhaust gas is higher than the ratio of acetaldehyde. Further, "the second exhaust gas contains acetaldehyde as a main component" means that the ratio of acetaldehyde in the first exhaust gas is higher than the ratio of ethanol.

In step D3, it is preferable that the flow rate for returning the first exhaust gas to step X and the flow rate for returning the second exhaust gas to step X can be adjusted by a flow rate indicator or the like. In step D3, the first exhaust gas and the second exhaust gas may be returned to the same step or may be returned to different steps.

In the recycling control step, it is preferable to start one or more of steps D1 to D3 when the molar ratio (ethanol / acetaldehyde) becomes 0.8 or less in the monitoring by the analyzer.
In the recycling control step, only one of steps D1 to D3 may be carried out, or two or more of steps D1 to D3 may be carried out in combination. Of these, a combination of steps D1 and D2 or a combination of steps D2 and D3 is preferable.

[1,3-Butadiene production equipment]
The 1,3-butadiene production apparatus of the present embodiment is a production apparatus for continuously producing 1,3-butadiene from an ethanol supply raw material containing ethanol. By using the 1,3-butadiene production apparatus of the present embodiment, the above-mentioned 1,3-butadiene production method of the present embodiment can be carried out.
The 1,3-butadiene production apparatus of the present embodiment includes gas preparation means, conversion means, purification means, and one or both of recycling means and recycling control means.

The gas preparation means is a means for step A, and is equipped with a vaporizer that vaporizes the ethanol supply raw material into an ethanol-containing gas. As the vaporizer, any known vaporizer can be used as long as it can vaporize the ethanol supply raw material.

The conversion means is a means for step B, and includes a reactor that converts ethanol in the ethanol-containing gas to 1,3-butadiene.
The reactor may be in any form as long as it can bring the gas into contact with the catalyst at a predetermined pressure and temperature. For example, an embodiment in which a catalyst is filled in a reaction tube in which a heat medium is circulated in a side wall portion to form a reaction bed, and the supplied gas is brought into contact with the catalyst of the reaction bed can be exemplified. The reaction bed is not particularly limited, and examples thereof include a fixed bed, a moving bed, and a fluidized bed.

The conversion means may include two or more parallel reactors. For example, in the case of a two-stage reaction, two or more parallel reactors for step B11 and two or more parallel reactors for step B12 may be provided. In the case of a one-stage reaction, two or more parallel reactors for step B13 may be provided.

The purification means is a means for step C, and includes, for example, a gas-liquid separator, a distillation column, a reactor, and other devices capable of purifying a crude gas containing 1,3-butadiene.
Step C1 can be carried out when the purification means includes a reactor. Step C2 can be carried out by providing the purification means with a gas-liquid separator. Step C3 and step C4 can be carried out when the purification means includes a distillation column. The purification means may be provided alone with one of the above-mentioned devices, or may be a combination of two or more devices.

The recycling means returns the vaporizer for vaporizing the C6 component and the C8 component in the exhaust gas discharged from the refining means and the exhaust gas after vaporizing the C6 component and the C8 component to at least the gas preparing means or the conversion means. It has at least piping.
In the recycling means, in addition to the vaporizer, the exhaust gas after vaporizing the C6 component and the C8 component is gas-liquid separated to form the gas components ethanol and acetaldehyde and the liquid components C6 component and C8 component. A gas-liquid separator may be provided to separate the gas and liquid. The gas-liquid separator is provided in the middle of the pipe for returning the exhaust gas from the vaporizer to the gas preparation means.

<First Embodiment>
Hereinafter, a method for producing 1,3-butadiene of the present embodiment and an example of an embodiment of the production apparatus will be specifically described. FIG. 1 is a schematic schematic diagram of the 1,3-butadiene manufacturing apparatus 100 of the first embodiment (hereinafter, also simply referred to as “manufacturing apparatus 100”). It should be noted that the dimensions and the like of the figures illustrated in the following description are examples, and the present invention is not necessarily limited thereto, and the present invention can be appropriately modified without changing the gist thereof. ..

"manufacturing device"
The manufacturing apparatus 100 includes a gas preparing means 1, a converting means 2, a refining means 3, and a recycling means 5.
The gas preparing means 1 includes a raw material accommodating unit 102, a vaporizer 104, and a diluting gas accommodating unit 106.
The conversion means 2 includes a first reactor 108 and a second reactor 110.
The purification means 3 includes a gas-liquid separator 112, a first distillation column 114, a third reactor 116, a second distillation column 118, and a recovery unit 120.
The recycling means 5 includes a vaporizer 61, a vaporization control device 69, a recycling control device 122, and a gas-liquid separator 124.

The raw material storage unit 102 and the vaporizer 104 are connected by a pipe 10. The pipe 10 is provided with a flow rate indicator controller 11. The vaporizer 104 and the first reactor 108 are connected by a pipe 12. The pipe 12 is provided with a pressure indicator controller 14, a mixer 16, a heat exchanger 18, a temperature indicator controller 20, and a valve 22 for adjusting the flow rate based on the pressure in the vaporizer 104 in this order from the vaporizer 104 side. ing. The dilution gas accommodating portion 106 is connected by a pipe 24 between the pressure indicator controller 14 and the mixer 16 in the pipe 12. The pipe 24 is provided with a flow rate indicator 26.

The first reactor 108 and the gas-liquid separator 124 are connected by a pipe 28. Further, the gas-liquid separator 124 and the second reactor 110 are connected by a pipe 30. As described above, in the manufacturing apparatus 100, the gas-liquid separator 124 is provided between the first reactor 108 and the second reactor 110 in the conversion means 2.

A valve 32 is provided at a position near the first reactor 108 of the pipe 28, and an analyzer 34 is provided on the downstream side of the valve 32. At a position near the gas-liquid separator 124 of the pipe 30, a pump 36 and a level indicator controller 38 that adjusts the flow rate based on the liquid level in the gas-liquid separator 124 are provided in this order. A valve 40 is provided at a position of the pipe 30 near the second reactor 110.

The second reactor 110 and the gas-liquid separator 112 are connected by a pipe 42. A valve 44 is provided at a position near the second reactor 110 of the pipe 42, and

heat exchangers

46 and 47 are provided at a position near the gas-liquid separator 112. The gas-liquid separator 112 and the first distillation column 114 are connected by a pipe 48. The pipe 48 is provided with a pump 50 and a level indicator controller 52 for adjusting the flow rate based on the liquid level in the gas-liquid separator 112 in this order from the gas-liquid separator 112 side.

A pipe 54 is connected to the top of the first distillation column 114. Further, a pipe 56 that is connected to the gas phase portion of the gas-liquid separator 112 and joins the pipe 54 is provided. The intermediate portion of the first distillation column 114 and the third reactor 116 are connected by a pipe 58. The third reactor 116 and the recovery unit 120 are connected by a pipe 60. The bottom of the first distillation column 114 and the second distillation column 118 are connected by a pipe 62. The top of the second distillation column 118 and the valve 32 in the pipe 28 and the analyzer 34 are connected by a pipe 64. A pipe 66 is connected to the bottom of the second distillation column 118. Further, a pipe 72 that is connected to the gas phase portion of the gas-liquid separator 124 and joins the pipe 54 is provided.

The recycling control device 122 includes a flow rate indicator 70 installed on the pipe 67 and the pipe 68. The recycling control device 122 can adjust the flow rates of the

pipes

67 and 68 by the flow rate indicator controller 70 based on the analysis result of the analyzer 34.

"Production method"
Hereinafter, the method for producing 1,3-butadiene of the first embodiment using the production apparatus 100 will be described with reference to FIG.
The ethanol supply raw material is sent from the raw material storage unit 102 to the vaporizer 104 through the pipe 10, and the ethanol supply raw material is vaporized under the conditions of a pressure of −1.0 to 3.0 MPaG and a temperature of -100 to 400 ° C. to contain ethanol. Use gas (step A1 described above). Ethanol-containing gas is sent from the vaporizer 104 to the pipe 12, nitrogen gas (dilution gas) is merged from the dilution gas accommodating portion 106 through the pipe 24, and mixed by the mixer 16. Then, the ethanol concentration of the ethanol-containing gas is adjusted within the range of 0.1 to 100% by volume (step A2 described above).

The ethanol-containing gas whose ethanol concentration has been adjusted is heated by the heat exchanger 18 and supplied to two or more parallel first reactors 108. In each of the first reactors 108, ethanol is converted to acetaldehyde in the presence of the first catalyst under the conditions of a pressure of 0 to 1.0 MPaG and a temperature of 50 to 500 ° C. (step B11 described above). An intermediate gas containing ethanol and acetaldehyde generated in each first reactor 108 is sent to the pipe 28. Further, an intermediate gas is supplied to the second reactor 110, and ethanol and acetaldehyde are converted to 1,3-butadiene in the presence of the second catalyst under the conditions of a pressure of 0 to 1.0 MPaG and a temperature of 50 to 500 ° C. (Step B12 described above).

The crude gas containing 1,3-butadiene is sent from the second reactor 110 to the pipe 42, cooled by the heat exchanger 46, and supplied to the gas-liquid separator 112. In the gas-liquid separator 112, the crude gas is separated into a hydrogen gas, a nitrogen gas (dilution gas) and a 1,3-butadiene-containing liquid (step C2 described above). The pump 50 is driven, and the 1,3-butadiene-containing liquid is supplied from the gas-liquid separator 112 to the first distillation column 114 through the pipe 48 for distillation. Ethylene-containing gas is extracted from the top of the first distillation column 114 into the pipe 54, acetaldehyde-containing liquid is extracted from the bottom of the column into the

pipe

62, and 1,3-butadiene-containing effluent is extracted from the intermediate portion into the pipe 58 (the above-described step). C3). The ethylene-containing gas extracted to the pipe 54 is combined with the hydrogen gas and the nitrogen gas (dilution gas) extracted from the gas phase portion of the gas-liquid separator 112 to the pipe 56 and treated as waste gas.

The 1,3-butadiene-containing effluent extracted from the pipe 58 is supplied to the third reactor 116, and 1-butene, 2-butene, and isobutene in the 1,3-butadiene-containing effluent are separated in the presence of the fourth catalyst. It is dehydrogenated and converted to 1,3-butadiene (step C1 described above). Purified 1,3-butadiene is sent from the third reactor 116 to the recovery unit 120 by the pipe 60 for recovery.

The acetaldehyde-containing liquid extracted from the bottom of the first distillation column 114 to the pipe 62 is supplied to the second distillation column 118 for distillation. The residual liquid containing water is extracted from the bottom of the second distillation column 118 into the pipe 66, and the acetaldehyde-containing gas is extracted from the top of the column 64 into the pipe 64 (step C4 described above). The residual liquid containing water extracted from the pipe 66 is treated as a waste liquid.

The acetaldehyde-containing gas (exhaust gas) extracted from the top of the second distillation column 118 (step C4 described above) is sent to the vaporizer 61 through the pipe 63, and the C6 component and C8 component in the exhaust gas are sufficiently heated. Vaporize to. The temperature of the gas emitted from the vaporizer 61 is monitored by the vaporization control device 69, and the heating temperature in the vaporizer 61 is adjusted.
The vaporized gas from the vaporizer 61 is returned to the pipe 28 through the pipe 68 and the pipe 64 and mixed with the intermediate gas. Further, the analyzer 34 analyzes the ethanol and acetaldehyde contents in the intermediate gas flowing through the pipe 28. Based on the analysis result, the flow rate of the vaporized gas separated into the pipe 67 is adjusted by the flow rate indicator regulator 70. As a result, the flow rate of the vaporized gas returned to the pipe 28 is adjusted, and when the ethanol content is high, more vaporized gas is sent to the gas preparing means 1, and when the acetaldehyde content is high, more vaporized gas is sent to the converting means 2. It can be controlled to send gas.

<Second Embodiment>
FIG. 2 is a schematic schematic view of the 1,3-butadiene manufacturing apparatus 100A (hereinafter, also referred to as “manufacturing apparatus 100A”) of the second embodiment. The same parts as those in FIG. 1 in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted.

"manufacturing device"
As the recycling means, the manufacturing apparatus 100A is provided with the recycling means 5A corresponding to the recycling means 5 of the first embodiment and the pipe 67A instead of the pipe 67, and the recycling means 5B having the gas-liquid separator 113 on the pipe 67A. The configuration is the same as that of the manufacturing apparatus 100 except that the manufacturing apparatus 100 is provided with.

The gas-liquid separator 113 liquefies the C6 component and the C8 component in the vaporized gas emitted from the vaporizer 61 and removes them from the vaporized gas. The gas component containing ethanol and acetaldehyde separated by the gas-liquid separator 113 is returned to the gas preparation means 1. The liquid component containing the C6 component and the C8 component separated by the gas-liquid separator 113 is sent to the pipe 54 through the pipe 49, the pump 51, and the pipe 55.

"Production method"
Hereinafter, a method for producing 1,3-butadiene according to the second embodiment using the production apparatus 100A will be described with reference to FIG.
In the method for producing 1,3-butadiene of the second embodiment using the production apparatus 100A, in the above-mentioned first embodiment, the vaporized gas returned to the gas preparation means may contain C6 component and C8 component. However, in this second embodiment, it can be carried out in the same manner as in the first embodiment using the manufacturing apparatus 100, except that the C6 component and the C8 component are removed from the vaporized gas and ethanol and acetaldehyde are returned to the gas preparation means.

When the total content of the C6 component and the C8 component in the exhaust gas from the second distillation column 118 is 0.5% by mass or more of the total mass of the organic compounds in the exhaust gas, the production method of the second embodiment is used. preferable. When the total content of C6 component and C8 component in the exhaust gas is 0.5% by mass or more of the total mass of the organic compounds in the exhaust gas, it is liquefied due to pressure loss and accumulated in the piping or pump and blocked. It tends to cause the equipment to increase or increase the operating cost of the equipment. Therefore, by returning at least a part of the high boiling point component removing gas obtained by removing at least a part of the high boiling point component from the exhaust gas to either one or both of step A and step B, the piping or The yield of 1,3-butadiene can be improved while preventing pump blockage or increased equipment operating costs.
Further, although not shown, when the content of the high boiling point component in the exhaust gas becomes large, at least a part of the high boiling point component may be removed and then supplied to the vaporizer. Means for removing at least a part of the high boiling point component include a filter, a gas-liquid separator, and the like.

<Third Embodiment>
The 1,3-butadiene production apparatus (not shown) of the third embodiment includes a trap means instead of the recycling means 5 of the first embodiment.

"manufacturing device"
The 1,3-butadiene production apparatus of the third embodiment includes gas preparation means, conversion means, purification means, and trap means.
The gas preparation means, the conversion means, and the purification means are the same as those of the 1,3-butadiene production apparatus 100 of the first embodiment described above.

The trap means includes a high boiling point component removing device for removing a high boiling point component in the exhaust gas from the refining means, and a pipe for returning the exhaust gas from which the high boiling point component has been removed to the gas preparing means or the converting means. At least I have.
The high boiling point component removing device is not particularly limited as long as it can remove at least a part of the high boiling point component in the exhaust gas, and examples thereof include a gas-liquid separator and a filter.
The trap means preferably includes an analyzer for measuring the content of high boiling point components in the exhaust gas. When the content of the high boiling point component in the exhaust gas is, for example, a high content of 0.5 to 1% by mass of the total mass of the organic compounds in the exhaust gas, clogging of pipes, pumps, etc. is likely to occur. , 1,3-butadiene production efficiency may decrease.

"Production method"
The method for producing 1,3-butadiene according to the third embodiment of the present invention will be described.
In the method for producing 1,3-butadiene of the third embodiment, in the above-mentioned first embodiment, the vaporized gas returned to the gas preparing means and / or the converting means may contain C6 component and C8 component. However, in this third embodiment, the manufacturing apparatus 100 is used except that ethanol and acetaldehyde are returned to the gas preparing means and / or the converting means after the C6 component and the C8 component in the exhaust gas are removed. It can be done in the same manner as in the embodiment.

<Fourth Embodiment>
FIG. 3 is a schematic schematic diagram of the 1,3-butadiene manufacturing apparatus 100B (hereinafter, also referred to as “manufacturing apparatus 100B”) according to the fourth A embodiment. FIG. 5 is a schematic schematic diagram of the 1,3-butadiene manufacturing apparatus 100C (hereinafter, also referred to as “manufacturing apparatus 100B”) according to the fourth B embodiment.

"manufacturing device"
The 1,3-butadiene production apparatus of the fourth embodiment includes gas preparation means, conversion means, purification means, and recycling control means.

The recycling control means is a pipe that returns at least a part of the exhaust gas (E / A) discharged from either one or both of the conversion means and the purification means to the gas preparation means or the conversion means, and downstream of the returned portion. It is equipped with at least an analyzer that analyzes the molar ratio (E / A) in the gas on the side. The analyzer may be any as long as it can analyze the molar ratio (E / A), and for example, a process mass spectrometer or the like can be exemplified.

Further, the recycling control means includes at least one selected from the group consisting of the first recycling control device, the second recycling control device and the third recycling control device, which will be described later.
Hereinafter, the gas preparing means or the converting means are collectively referred to as means X.
The first recycling control device is for separating a part of the exhaust gas and returning the rest to the means X (step D1). The first recycling control device includes, for example, a pipe connecting an exhaust gas (E / A) discharge part in a conversion means or a purification means and a part for returning an exhaust gas (E / A) of a gas preparation means or a conversion means, and discharge. It is provided with a branch pipe branched from a pipe for returning gas (E / A) and a flow rate indicator controller provided in the branch pipe.

The second recycling control device returns at least a part of the exhaust gas (E / A) to the means X, and separates a part of acetaldehyde from the gas in the step of returning the exhaust gas (E / A) to the means X (step). It is for D2). The second recycling control device includes, for example, a pipe for returning the exhaust gas (E / A) to the means X, and a gas-liquid separator provided on the downstream side of the portion where the exhaust gas (E / A) is returned to the means X. It is equipped with a separation device such as a distillation column and a scrubber.

The third recycling control device is for separating the first exhaust gas containing ethanol as a main component and the second exhaust gas containing acetaldehyde as a main component and returning them to means X (process D3). For example, the third recycling control device includes a first pipe for returning the first exhaust gas containing ethanol as a main component to the means X, and a second pipe for returning the second exhaust gas containing acetaldehyde as a main component to the means X. It is preferable that each of the first pipe and the second pipe is provided with a flow rate indicator so that the flow rate of the first exhaust gas and the flow rate of the second exhaust gas can be adjusted separately.

[Fourth A Embodiment]
Hereinafter, a method for producing 1,3-butadiene of the present embodiment and an example of an embodiment of the production apparatus will be specifically described. FIG. 3 is a schematic schematic diagram of the 1,3-butadiene manufacturing apparatus 100B (hereinafter, also referred to as “manufacturing apparatus 100B”) according to the fourth A embodiment.

(manufacturing device)
The manufacturing apparatus 100B includes a gas preparing means 1, a converting means 2, a refining means 3, and a recycling control means 4.
The gas preparing means 1 includes a raw material accommodating unit 102, a vaporizer 104, and a diluting gas accommodating unit 106. The conversion means 2 includes a first reactor 108 and a second reactor 110. The purification means 3 includes a gas-liquid separator 112, a first distillation column 114, a third reactor 116, a second distillation column 118, and a recovery unit 120. The recycling control means 4 includes a first recycling control device 122 and a gas-liquid separator (second recycling control device) 124.

The first reactor 108 and the gas-liquid separator 124 are connected by a pipe 28. Further, the gas-liquid separator 124 and the second reactor 110 are connected by a pipe 30. As described above, in the manufacturing apparatus 100B, the second recycling control device (gas-liquid separator 124) is provided between the first reactor 108 and the second reactor 110 in the conversion means 2.

The second reactor 110 and the gas-liquid separator 112 are connected by a pipe 42. A valve 44 is provided at a position near the second reactor 110 of the pipe 42, and a heat exchanger 46 is provided at a position near the gas-liquid separator 112. The gas-liquid separator 112 and the first distillation column 114 are connected by a pipe 48. The pipe 48 is provided with a pump 50 and a level indicator controller 52 for adjusting the flow rate based on the liquid level in the gas-liquid separator 112 in this order from the gas-liquid separator 112 side.

The first recycling control device 122 includes a pipe 68 that branches from the pipe 64 and joins the pipe 54, and a flow rate indicator adjuster 70 provided in the pipe 68. The first recycling control device 122 can adjust the flow rate of the pipe 68 by the flow rate indicator controller 70 based on the analysis result of the analyzer 34.

(Production method)
Hereinafter, the method for producing 1,3-butadiene of the first embodiment using the production apparatus 100B will be described with reference to FIGS. 3 and 4.
The ethanol supply raw material is sent from the raw material storage unit 102 to the vaporizer 104 through the pipe 10, and the ethanol supply raw material is vaporized under the conditions of a pressure of −1.0 to 3.0 MPaG and a temperature of -100 to 400 ° C. to contain ethanol. Use gas (step A1). Ethanol-containing gas is sent from the vaporizer 104 to the pipe 12, nitrogen gas (dilution gas) is merged from the dilution gas accommodating portion 106 through the pipe 24, and mixed by the mixer 16. Then, the ethanol concentration of the ethanol-containing gas is adjusted within the range of 0.1 to 100% by volume (step A2).

The ethanol-containing gas whose ethanol concentration has been adjusted is heated by the heat exchanger 18 and supplied to two or more parallel first reactors 108. In each of the first reactors 108, ethanol is converted to acetaldehyde in the presence of the first catalyst under the conditions of a pressure of 0 to 1.0 MPaG and a temperature of 50 to 500 ° C. (step B11). An intermediate gas containing ethanol and acetaldehyde generated in each first reactor 108 is sent to the pipe 28. Further, an intermediate gas is supplied to the second reactor 110, and ethanol and acetaldehyde are converted to 1,3-butadiene in the presence of the second catalyst under the conditions of a pressure of 0 to 1.0 MPaG and a temperature of 50 to 500 ° C. (Step B12).

The crude gas containing 1,3-butadiene is sent from the second reactor 110 to the pipe 42, cooled by the heat exchanger 46, and supplied to the gas-liquid separator 112. In the gas-liquid separator 112, the crude gas is separated into a hydrogen gas, a nitrogen gas (dilution gas) and a 1,3-butadiene-containing liquid (step C2). The pump 50 is driven, and the 1,3-butadiene-containing liquid is supplied from the gas-liquid separator 112 to the first distillation column 114 through the pipe 48 for distillation. Ethylene-containing gas is extracted from the top of the first distillation column 114 into the pipe 54, acetaldehyde-containing liquid is extracted from the bottom of the column into the

pipe

62, and 1,3-butadiene-containing effluent is extracted from the intermediate portion into the pipe 58 (step C3). .. The ethylene-containing gas extracted to the pipe 54 is combined with the hydrogen gas and the nitrogen gas (dilution gas) extracted from the gas phase portion of the gas-liquid separator 112 to the pipe 56 and treated as waste gas.

The 1,3-butadiene-containing effluent extracted from the pipe 58 is supplied to the third reactor 116, and 1-butene, 2-butene, and isobutene in the 1,3-butadiene-containing effluent are separated in the presence of the fourth catalyst. It is dehydrogenated and converted to 1,3-butadiene (step C1). Purified 1,3-butadiene is sent from the third reactor 116 to the recovery unit 120 by the pipe 60 for recovery.

The acetaldehyde-containing liquid extracted from the bottom of the first distillation column 114 to the pipe 62 is supplied to the second distillation column 118 for distillation. The residual liquid containing water is extracted from the bottom of the second distillation column 118 into the pipe 66, and the acetaldehyde-containing gas is extracted from the top of the column 64 into the pipe 64 (step C4). The residual liquid containing water extracted from the pipe 66 is treated as a waste liquid.

The acetaldehyde-containing gas (exhaust gas (E / A)) extracted from the top of the second distillation column 118 (step C4) is returned to the pipe 28 through the pipe 64 and mixed with the intermediate gas. Further, the molar ratio (E / A) in the intermediate gas flowing through the pipe 28 is analyzed by the analyzer 34. Based on the analysis result, the flow rate of the acetaldehyde-containing gas (exhaust gas (E / A)) separated into the pipe 68 is adjusted by the flow rate indicator regulator 70. As a result, the flow rate of the acetaldehyde-containing gas (exhaust gas (E / A)) returned to the pipe 28 is adjusted, and the molar ratio (E / A) of the intermediate gas supplied to the second reactor 110 is adjusted to the range of 1 to 100. (Step D1). Further, based on the analysis result of the analyzer 34, the molar ratio (E / A) of the intermediate gas supplied to the second reactor 110 can also be obtained by separating a part of acetaldehyde from the intermediate gas in the gas-liquid separator 124. Is adjusted to the range of 1 to 100 (step D2).
In the first embodiment, only one of the steps D1 and D2 may be performed, or both may be performed in combination.

[Fourth B Embodiment]
FIG. 5 is a schematic schematic view of the 1,3-butadiene manufacturing apparatus 100C (hereinafter, also referred to as “manufacturing apparatus 100C”) according to the fourth B embodiment. The same parts as those in FIG. 3 in FIG. 5 are designated by the same reference numerals, and the description thereof will be omitted.

(manufacturing device)
The manufacturing apparatus 100C has the same embodiment as the manufacturing apparatus 100B except that the recycling control means 4A is provided instead of the recycling control means 4. The recycling control means 4A has the same embodiment as the recycling control means 4 except that the third recycling control device 126 is provided instead of the first recycling control device 122.

The third recycling control device 126 includes the first pipe 74 connecting the middle portion of the second distillation column 118 near the top of the column and the valve 32 in the pipe 28 and the analyzer 34, and the second distillation column 118. A second pipe 78 that connects the top of the column and the valve 32 in the pipe 28 and the analyzer 34 is provided.

The first pipe 74 is provided with a flow rate indicator adjuster 76, and the second pipe 78 is provided with a flow rate indicator adjuster 80. The third recycling control device 126 can adjust the flow rates of the first pipe 74 and the second pipe 78 by the flow rate indicator controller 76 and the flow rate indicator controller 80 based on the analysis result of the analyzer 34.

(Production method)
Hereinafter, a method for producing 1,3-butadiene according to the fourth B embodiment using the production apparatus 100C will be described with reference to FIGS. 5 and 6.
The method for producing 1,3-butadiene in the fourth B embodiment using the manufacturing apparatus 100C can be performed in the same manner as in the fourth A embodiment using the manufacturing apparatus 100B, except that the step D3 is performed instead of the step D1.

Specifically, in step D3, the first exhaust gas containing ethanol as a main component extracted from the middle part of the second distillation column 118 (process C4) near the top of the column is returned to the pipe 28 through the first pipe 74. Mix with intermediate gas. Further, the acetaldehyde-containing gas (second exhaust gas) extracted from the top of the second distillation column 118 (process C4) is returned to the pipe 28 through the second pipe 78 and mixed with the intermediate gas. Further, based on the analysis result of the molar ratio (E / A) in the intermediate gas flowing through the pipe 28 by the analyzer 34, the flow rate of the first exhaust gas returned to the pipe 28 by the flow rate indicator controller 76 and the flow rate indicator controller 80. And the flow rate of the second exhaust gas are adjusted respectively. As a result, the molar ratio (E / A) of the intermediate gas supplied to the second reactor 110 is adjusted to the range of 1 to 100.
In the second embodiment, only one of the steps D2 and D3 may be performed, or both may be performed in combination.

As described above, in the present invention, the molar ratio of the gas to be subjected to the conversion reaction to 1,3-butadiene while performing steps A to D and recycling at least a part of the exhaust gas that has been conventionally discarded ( By controlling the E / A) to a specific range, 1,3-butadiene can be continuously produced in a high yield.

The method for producing 1,3-butadiene of the present embodiment is not limited to the above-described embodiment, and the configurations described in each step can be appropriately combined. It is possible to replace the components in the above embodiment with well-known components as appropriate without departing from the spirit of the present invention.

1 ... Gas preparation means, 2 ... Conversion means, 3 ... Purification means, 4 ... Recycling control means, 5, 5A, 5B ... Recycling means, 10 ... Piping, 11 ... Flow indicator, 12 ... Piping, 14 ... Pressure indication Controller, 16 ... Mixer, 18 ... Heat exchanger, 20 ... Temperature indicator, 21 ... Vapor, 22 ... Valve, 24 ... Piping, 26 ... Flow indicator, 28 ... Piping, 30 ... Piping, 32 ... Valve, 34 ... Analyzer, 36 ... Pump, 38 ... Level indicator, 40 ... Valve, 42 ... Piping, 44 ... Valve, 45 ... Heat exchanger, 46 ... Heat exchanger, 47 ... Heat exchanger, 48 ... Piping, 49 ... Piping, 50 ... Pump, 51 ... Pump, 52 ... Level indicator, 53 ... Level indicator, 54 ... Piping, 55 ... Piping, 56 ... Piping, 58 ... Piping, 60 ... Piping, 61 ... Vaporizer, 62 ... Piping, 63 ... Piping, 64 ... Piping, 66 ... Piping, 68 ... Piping, 69 ... Vaporization control device, 70 ... Flow indicator controller, 72 ... Piping, 74 ... First piping, 76 ... Flow indicator Controller, 78 ... 2nd pipe, 80 ... Flow indicator, 100, 100A, 100B, 100C ... Manufacturing equipment, 102 ... Raw material storage unit, 103 ... STM storage unit, 104 ... Vaporizer, 106 ... Gas storage for dilution Part, 108 ... 1st reactor, 110 ... 2nd reactor, 112 ... gas-liquid separator, 113 ... gas-liquid separator, 114 ... first distillation column, 116 ... third reactor, 118 ... second distillation column , 120 ... Recovery unit, 122 ... Recycling control device, 123 ... First recycling control device, 124 ... Gas-liquid separator (second recycling control device), 126 ... Third recycling control device

Claims

A method for continuously producing 1,3-butadiene from an ethanol feedstock containing ethanol.
A gas preparation step for preparing an ethanol-containing gas from the ethanol supply raw material, and
A conversion step of converting ethanol in the ethanol-containing gas to 1,3-butadiene in the presence of a catalyst, and
A purification step of purifying the crude gas containing 1,3-butadiene obtained in the conversion step to obtain purified 1,3-butadiene, and a purification step.
Including one or more of a recycling process, a trapping process, and a recycling control process.
The recycling step is the exhaust gas discharged in the purification step, and at least a part of the exhaust gas containing one or both of ethanol and acetaldehyde and a high boiling point component having a boiling point higher than that of ethanol and acetaldehyde. It is a step of returning at least a part of the vaporized gas obtained by heating to one or both of the gas preparation step and the conversion step.
The trap step is a high boiling point from the exhaust gas discharged in the purification step, which contains one or both of ethanol and acetaldehyde and a high boiling point component having a boiling point higher than that of ethanol and acetaldehyde. This is a step of returning at least a part of the high boiling point component removing gas obtained by removing at least a part of the components to one or both of the gas preparation step and the conversion step.
The recycling control step is an exhaust gas discharged from either one or both of the conversion step and the purification step, and at least a part of the exhaust gas containing either one or both of ethanol and acetaldehyde is used as the gas. It is a step of returning to the step X selected from the preparation step and the conversion step and controlling the molar ratio (ethanol / acetaldehyde) in the gas of the step to 1 to 100.
Step D1 in which a part of the exhaust gas is separated and the balance is returned to the step X, and step D2 in which at least a part of the exhaust gas is returned to the step X and a part of acetaldehyde is separated from the gas in the step X. At least one selected from the group consisting of the first exhaust gas containing ethanol as the main component and the second exhaust gas containing acetaldehyde as the main component and returning to the step X as the exhaust gas. A method for producing 1,3-butadiene, including one.
The method for producing 1,3-butadiene according to claim 1, wherein the high boiling point component contains either one or both of a compound having 6 carbon atoms and a compound having 8 carbon atoms.
The claim that when at least a part of the vaporized gas is returned to the gas preparation step in the recycling step, at least a part of the high boiling point component in the vaporized gas is removed and then returned to the gas preparation step. The method for producing 1,3-butadiene according to 1 or 2.
The method for producing 1,3-butadiene according to claim 3, wherein the total content of the high boiling point component in the exhaust gas is 0.5 to 1% by mass of the total mass of the organic compound in the exhaust gas. ..
The method for producing 1,3-butadiene according to claim 1 or 2, wherein at least a part of the high boiling point component is gas-liquid separated and removed in the trap step.
The method for producing 1,3-butadiene according to claim 5, wherein the total content of the high boiling point component in the exhaust gas is 0.5 to 1% by mass of the total mass of the organic compound in the exhaust gas. ..
1. The one according to claim 1, wherein one or more of the step D1, the step D2, and the step D3 is carried out based on the result of monitoring the molar ratio (ethanol / acetaldehyde) in the step X with an analyzer. , 3-butadiene production method.
The seventh aspect of claim 7, wherein one or more of the step D1, the step D2, and the step D3 is started when the molar ratio (ethanol / acetaldehyde) becomes 0.8 or less in the monitoring by the analyzer. Method for producing 1,3-butadiene.
Any one of claims 1 to 8, wherein in the step D2, the gas of the step X is introduced into the separation device, and a part of acetaldehyde is separated in the separation device under a pressure of 1.0 to 5.0 MPa. The method for producing 1,3-butadiene according to.
The method for producing 1,3-butadiene according to any one of claims 1 to 9, wherein in the step D3, the flow rate for returning the first exhaust gas and the flow rate for returning the second exhaust gas are adjusted, respectively.
The gas preparation step includes the step A1 of vaporizing the ethanol supply raw material into the ethanol-containing gas under the conditions of a pressure of −1.0 to 3.0 MPaG and a temperature of −100 to 400 ° C. 10. The method for producing 1,3-butadiene according to any one of 10.
The conversion step comprises at least step B1 of converting ethanol in the ethanol-containing gas to 1,3-butadiene in the presence of a catalyst under conditions of a pressure of 0 to 1.0 MPaG and a temperature of 50 to 500 ° C. A step B2 for separating a gas containing hydrogen from the ethanol-containing gas supplied to the step B1 by liquid separation, a step B3 for separating a gas containing nitrogen from the gas after the step B1 by gas-liquid separation, and a distillation. Any one of claims 1 to 11, wherein at least one selected from the group consisting of the step B4 for separating the gas containing acetaldehyde from the ethanol-containing gas supplied to the step B1 may be combined with the step B1. The method for producing 1,3-butadiene according to the section.
The purification step includes step C1 in which butene in the crude gas is dehydrogenated and converted to 1,3-butadiene, and 1,3-, which separates hydrogen gas from the crude gas by gas-liquid separation. Step C2 to obtain a butadiene-containing liquid, and step C3 to distill the liquefied crude gas or the 1,3-butadiene-containing liquid into an ethylene-containing gas, a 1,3-butadiene-containing effluent, and an acetaldehyde-containing liquid. To any one of claims 1 to 12, which comprises at least one selected from the group consisting of the step C4 of distilling the acetaldehyde-containing liquid and separating the acetaldehyde-containing gas into a residual liquid containing water. The method for producing 1,3-butadiene according to the above method.
A manufacturing device that continuously produces 1,3-butadiene from an ethanol supply raw material containing ethanol.
It comprises gas preparation means, conversion means, purification means, and one or more means of recycling means, trap means, and recycling control means.
The gas preparing means includes a vaporizer that vaporizes the ethanol supply raw material into an ethanol-containing gas.
The conversion means includes a reactor that converts ethanol in the ethanol-containing gas to 1,3-butadiene.
The purification means is a means for purifying the crude gas containing 1,3-butadiene obtained by the conversion means.
The recycling means is an exhaust gas discharged from the purification means, and is a vaporizer that heats at least a part of the exhaust gas containing either one or both of ethanol and acetaldehyde to generate a vaporized gas, and the vaporization means. At least provided with at least a pipe for returning the gas to the gas preparing means or the converting means.
The trap means includes a high boiling point component removing device that removes at least a part of a high boiling point component having a boiling point higher than that of ethanol and acetaldehyde in the exhaust gas discharged from the purification means, and an exhaust gas from which the high boiling point component has been removed. At least provided with the gas preparation means or the piping for returning to the conversion means,
The recycling control means is exhaust gas discharged from either one or both of the conversion means and the purification means, and at least a part of the exhaust gas containing either one or both of ethanol and acetaldehyde, at least the above-mentioned. It is equipped with at least a pipe for returning to the means X selected from the gas preparing means and the conversion means, and an analyzer for analyzing the molar ratio (ethanol / acetaldehyde) in the gas on the downstream side of the returned portion, and further, the exhaust gas. A first recycling control device that separates a part of the gas and returns the rest to the means X, and a first that returns at least a part of the exhaust gas to the means X and separates a part of acetaldehyde from the gas of the means X. 2 A third recycling including a recycling control device, a first pipe for returning the first exhaust gas containing ethanol as a main component to the means X, and a second pipe for returning the second exhaust gas containing acetaldehyde as a main component to the means X. A 1,3-butadiene production device comprising a control device and at least one selected from the group consisting of.
The 1,3-butadiene manufacturing apparatus according to claim 14, wherein in the recycling means, a gas-liquid separator is installed in the middle of a pipe for returning the vaporized gas to the gas preparing means.