KR102564959B1 - Method for preparing 1,3-butadiene - Google Patents

Abstract

An exemplary embodiment of the present application includes introducing a reactant including butene and oxygen into a first reactor, and performing an oxidative dehydrogenation process in the first reactor; And the first product formed through the first reactor and oxygen are introduced into a second reactor connected in series with the first reactor, and the first product formed through the first reactor is 1,3-butadiene, light ) component and a heavy component, and providing a method for producing 1,3-butadiene comprising the step of removing the heavy component in the second reactor.

Description

Method for producing 1,3-butadiene {METHOD FOR PREPARING 1,3-BUTADIENE}

This application relates to a method for producing 1,3-butadiene.

1,3-butadiene is an intermediate for petrochemical products, and its demand and value are gradually increasing worldwide. The 1,3-butadiene is produced using naphtha cracking, direct dehydrogenation of butene, oxidative dehydrogenation of butene, and the like.

The naphtha cracking process not only consumes a lot of energy due to the high reaction temperature, but also has a problem in that base oils other than 1,3-butadiene are produced in excess because it is not a single process for producing 1,3-butadiene. In addition, the direct dehydrogenation reaction of n-butene is not only thermodynamically unfavorable, but also requires high temperature and low pressure conditions to produce 1,3-butadiene with a high yield as an endothermic reaction, thus commercializing 1,3-butadiene production. Not suitable for process.

Therefore, a technique for producing 1,3-butadiene using the oxidative dehydrogenation of butene is widely known.

US Patent Publication No. 2016-0152529

This application provides a method for producing 1,3-butadiene.

An exemplary embodiment of the present application,

Injecting a reactant including butene and oxygen into a first reactor, and performing an oxidative dehydrogenation process in the first reactor; and

The first product and oxygen formed through the first reactor are introduced into a second reactor connected in series with the first reactor, and the first product formed through the first reactor is 1,3-butadiene, light components and heavy components, and removing the heavy components in the second reactor.

It provides a method for producing 1,3-butadiene comprising a.

According to an exemplary embodiment of the present application, by sequentially performing a first reactor process in which an oxidative dehydrogenation process is performed and a second reactor process in which heavy components are removed, heavy components can be effectively removed, and selectivity of butadiene can improve In addition, according to an exemplary embodiment of the present application, by including a second reactor process for removing heavy components, the load of the subsequent purification process can be reduced.

In addition, according to an exemplary embodiment of the present application, COD (Chemical Oxygen Demand) of generated wastewater is low, and thus wastewater can be recycled to secure economic feasibility.

1 is a diagram schematically showing a manufacturing process of 1,3-butadiene according to Example 1 of the present application.
2 is a diagram schematically showing a manufacturing process of 1,3-butadiene according to Comparative Example 2 of the present application.

Hereinafter, this specification will be described in more detail.

In the present specification, 'yield (%)' is defined as a value obtained by dividing the weight of 1,3-butadiene (BD), a product of oxidative dehydrogenation, by the weight of butene (BE), a raw material. For example, the yield can be expressed by the following formula.

Yield (%) = [(number of moles of 1,3-butadiene produced) / (number of moles of supplied butene)] × 100

In the present specification, 'conversion (%)' refers to the rate at which a reactant is converted into a product, and for example, the conversion rate of butene may be defined by the following equation.

Conversion rate (%) = [(number of moles of butenes reacted) / (number of moles of butenes supplied)] × 100

In the present specification, 'selectivity (%)' is defined as a value obtained by dividing the amount of change in butadiene by the amount of change in butene. For example, selectivity can be expressed by the following formula.

Selectivity (%) = [(Number of moles of 1,3-butadiene or COx produced) / (Number of moles of reacted butene)] × 100

In the present specification, 'hot spot' means a place where the temperature is the highest in the reactor.

In general, in the process of producing 1,3-butadiene using an oxidative dehydrogenation reaction of reactants including butene, heavy components including aldehydes are generated. Due to the heavy component, there is a problem that clogging of the downstream line may occur or a load may be applied to the purification process. In addition, the COD of the wastewater is increased by the heavy component, and when the wastewater is recycled into a reactor in which an oxidative dehydrogenation reaction is performed, a decrease in activity may occur.

In addition, when the catalyst layer for the oxidative dehydrogenation reaction and the catalyst layer for the heavy component removal are filled together in one reactor, the effect of improving the selectivity of the produced 1,3-butadiene is small, and the temperature of the catalyst layers is reduced. There is difficulty in controlling.

In order to solve these problems, the present application tried to provide a method for producing 1,3-butadiene that can effectively remove heavy components and improve the selectivity of butadiene using two reactors.

An exemplary embodiment of the present application includes introducing a reactant including butene and oxygen into a first reactor, and performing an oxidative dehydrogenation process in the first reactor; And the first product formed through the first reactor and oxygen are introduced into a second reactor connected in series with the first reactor, and the first product formed through the first reactor is 1,3-butadiene, light ) component and a heavy component, and providing a method for producing 1,3-butadiene comprising the step of removing the heavy component in the second reactor.

In an exemplary embodiment of the present application, the first reactor used for the oxidative dehydrogenation reaction is not particularly limited if it is a reactor that can be used for the oxidative dehydrogenation reaction, but, for example, the reaction temperature of the installed catalyst layer is kept constant. It may be a reactor in which the oxidative dehydrogenation reaction proceeds while the reactants continuously pass through the catalyst layer, and specific examples may be a tubular reactor, a batch reactor, a fluidized bed reactor, or a fixed bed reactor, and the fixed bed reactor is, for example, a shell and tube reactor. or a plate type reactor.

In one embodiment of the present application, an oxidative dehydrogenation process is performed in the first reactor, and the process in the first reactor may be performed at a temperature of 330 ° C to 450 ° C, and 350 ° C to 450 ° C. It may be carried out at a temperature of 430 °C. It is possible to provide 1,3-butadiene with high productivity due to excellent reaction efficiency without significantly increasing energy costs in the above temperature range.

In addition, in the second reactor, a process of removing heavy components present in the first product formed by passing through the first reactor is performed, and the process in the second reactor may be performed at a temperature of 200 ° C to 300 ° C, It may be carried out at a temperature of 220 ° C to 280 ° C. When the process in the second reactor satisfies the above-described temperature range, heavy components present in the first product may be effectively removed. When the process in the second reactor exceeds 300° C., a side reaction of the first product formed through the first reactor may occur, and heavy components may be additionally generated.

In one embodiment of the present application, the reactant including butene includes a C4 mixture, and the C4 mixture:oxygen may be introduced into the first reactor at a molar ratio of 1:0.4 to 0.6, and 1:0.45 to 0.55 It may be added in a molar ratio of In addition, in one embodiment of the present application, the first product formed by passing through the first reactor: oxygen may be introduced into the second reactor at a molar ratio of 1:0.3 to 0.5, and at a molar ratio of 1:0.35 to 0.45. can be put in When the molar ratio is out of the range, when the amount of oxygen is excessive, the catalyst may be quickly deactivated due to high heat generation, and when the amount of oxygen is insufficient, the catalyst may be deactivated because oxygen consumed in the catalyst is not replenished. In addition, when the amount of oxygen introduced into the second reactor is excessive, the oxygen concentration of the gas at the end of the purification process may be saturated and may be included in the explosive range, which is not preferable.

In an exemplary embodiment of the present application, the reactant including butene may be a raw material including C4 fraction, steam, and nitrogen (N ₂ ).

In an exemplary embodiment of the present application, the step of oxidative dehydrogenation is a raw material containing C4 oil, steam, oxygen (O ₂ ) and nitrogen (N ₂ ) at 330 ° C to 450 ° C, 330 ° C to 430 ° C, or 350 ° C to 425 ° C, the reaction efficiency is excellent without significantly increasing the energy cost within this range, so that 1,3-butadiene can be provided with high productivity, and the catalyst Activity and stability can be kept high.

The oxidative dehydrogenation reaction is, for example, 50h ^-1 to 2,000h ^-1 , 50h ^-1 to 1,500h ^-1 , or 50h ^-1 to 1,000h ^-1 based on normal butene at a space velocity (GHSV: Gas Hourly Space Velocity), and the reaction efficiency is excellent within this range, so that conversion rate, selectivity, yield, etc. are excellent.

The C4 fraction may refer to C4 raffinate-1, 2, and 3 remaining after separating useful compounds from the C4 mixture produced by naphtha cracking, and refers to C4 types obtained through ethylene dimerization it may be

The C4 fraction consists of n-butane, trans-2-butene, cis-2-butene, and 1-butene It may be one or a mixture of two or more selected from the group.

In the oxidative dehydrogenation reaction, the steam or nitrogen (N ₂ ) is a diluent gas introduced for the purpose of reducing the risk of explosion of reactants, preventing coking of a catalyst, and removing reaction heat.

The oxygen (O ₂ ), as an oxidant, reacts with the C4 fraction to cause a dehydrogenation reaction.

In an exemplary embodiment of the present application, the oxidative dehydrogenation reaction may be performed according to Scheme 1 or Scheme 2 below.

[Scheme 1]

C ₄ H ₈ + 1/2 O ₂ → C ₄ H ₆ + H ₂ O

[Scheme 2]

C ₄ H ₁₀ + O ₂ → C ₄ H ₆ + 2H ₂ O

Butadiene is produced by removing hydrogen from butane or butene through the oxidative dehydrogenation reaction. Meanwhile, in the oxidative dehydrogenation reaction, in addition to the main reaction shown in Scheme 1 or 2, side reaction products including carbon monoxide (CO) or carbon dioxide (CO ₂ ) may be produced. The side reaction product may include a process of being separated and discharged to the outside to prevent continuous accumulation in the process.

In one embodiment of the present application, the first reactor may include a first catalyst layer for oxidative dehydrogenation. The first catalyst layer may include at least one of a bismuth-molybdenum catalyst and a ferrite catalyst.

The ferrite-based catalyst may be represented by Formula 1 below.

[Formula 1]

AFe ₂ O ₄

In Formula 1, A is Cu, Ra, Ba, Sr, Ca, Cu, Be, Zn, Mg, Mn, Co or Ni.

In one embodiment of the present application, the ferrite-based catalyst is preferably a zinc ferrite catalyst.

The bismuth-molybdenum-based catalyst may be represented by Formula 2 below.

[Formula 2]

Mo _a Bi _b Fe _c Co _d E _e O _y

In Formula 2, E is at least one selected from among nickel, sodium, potassium, rubidium and cesium,

a, b, c, d and e are, when a is 10, b, c, d and e are 0.1 to 10, 0.1 to 10, 1 to 20, and 0 to 5, respectively;

y is a value determined to match the valency by other elements.

According to an exemplary embodiment of the present application, the light component is one or more selected from the group consisting of hydrogen, oxygen, nitrogen, carbon dioxide, carbon monoxide, water vapor, methane, ethylene, acetaldehyde, 1-butene, 2-butene, and vinylacetylene. may be an ingredient. However, it is not limited thereto, and may further include impurities of light components that are typically added in the oxidative dehydrogenation of butene.

According to an exemplary embodiment of the present application, the heavy component is aldehyde, acrolein, furan, butanone, benzene, 4-vinylcyclohexene, styrene, 4-formylcyclohexene, benzofuran, 3-acetyl-1-cyclohexene , cyclohexene dicarboxy, benzophenone, and 9-fluorenone may be one or more components selected from the group consisting of. However, it is not limited thereto, and may further include heavy impurities typically added in the oxidative dehydrogenation of butene.

According to an exemplary embodiment of the present application, the light component may mean a compound having a lower molecular weight than 1,3-butadiene, and the heavy component may mean a compound having a higher molecular weight than 1,3-butadiene.

In one embodiment of the present application, the second reactor may include a second catalyst layer for the removal reaction of heavy components present in the first product formed by passing through the first reactor. The second catalyst layer may include a catalyst in which at least one metal selected from among Cu, Mn, Ce, Zn, Fe, and Zr is supported on zeolite, and particularly, aldehyde removal efficiency may be high.

According to an exemplary embodiment of the present application, in the method for producing 1,3-butadiene, the butene conversion rate may be 72% or more, preferably 72.5% or more, and more preferably 79% or more.

According to an exemplary embodiment of the present application, in the method for producing 1,3-butadiene, the butadiene selectivity may be 85% or more, preferably 85.8% or more, and more preferably 87% or more. .

According to an exemplary embodiment of the present application, the yield of butadiene may be 74% or more, and preferably 74.4% or more.

According to an exemplary embodiment of the present application, by sequentially performing a first reactor process in which an oxidative dehydrogenation process is performed and a second reactor process in which heavy components are removed, heavy components can be effectively removed, and selectivity of butadiene can improve In addition, according to an exemplary embodiment of the present application, by including a second reactor process for removing heavy components, the load of the subsequent purification process can be reduced.

In addition, according to an exemplary embodiment of the present application, COD (Chemical Oxygen Demand) of generated wastewater is low, and thus wastewater can be recycled to secure economic feasibility.

In addition, according to an exemplary embodiment of the present application, the selectivity of butadiene is improved because the efficiency of removing heavy components is superior to the case where the catalyst layer for oxidative dehydrogenation reaction and the catalyst layer for removing the heavy components are filled together in one reactor. It has the effect of improving the temperature of the catalyst layer for the oxidative dehydrogenation reaction and the catalyst layer for the removal of the heavy component, and is characterized by easy temperature control. Accordingly, according to an exemplary embodiment of the present application, 1,3-butadiene can be produced in high yield.

Hereinafter, examples will be described in detail in order to specifically describe the present specification. However, embodiments according to the present specification may be modified in many different forms, and the scope of the present specification is not construed as being limited to the embodiments described below. The embodiments herein are provided to more completely explain the present specification to those skilled in the art.

< Example >

< manufacturing example 1> Preparation of catalyst

A catalyst slurry is prepared by coprecipitation by mixing water in which ZnCl ₂ , FeCl ₃ 6H ₂ O is dissolved with water in which ammonia water is dissolved, and filtering and residual ions are washed using a filter press, followed by drying and calcining. A catalyst on zinc ferrite was synthesized in the manner described above. After pulverizing and sieving the synthesized catalyst, it was dispersed in water, mixed with a sphere-shaped alumina support, and catalyst coating was performed by a wet method in which water was evaporated under reduced pressure.

< Example 1>

1) Catalytic filling

The first reactor for the oxidative dehydrogenation reaction used a cylindrical shell-and-tube reactor having an inner diameter of 2.54 cm. After placing a mesh stand capable of supporting the catalyst at the bottom of the reactor, 50 cc of alumina balls having a diameter of 3 mm were filled, 1,000 cc of the catalyst of Preparation Example 1 was filled thereon, and a 3 mm diameter alumina ball was filled thereon. An alumina ball was filled with 350 cc.

2) Normal- of butene dehydrogenation reaction

The structure of the reactor for producing butadiene in Example 1 is shown in FIG. A mixture of trans-2-butene and cis-2-butene was used as a reaction feed. One or more C4 and C5 chemicals such as 1-butene, isobutene, isobutylene, butane, and butadiene are present in the reaction feed. can be mixed.

The reaction feed (feed) was injected so that the space velocity for the catalyst was 250h ^-1 based on 1-butene or 2-butene. Oxygen was introduced into the first reactor at a molar ratio of 0.47 based on the amount of 2-butene initially introduced. Nitrogen was introduced into the first reactor at a molar ratio of 1.87 based on the amount of 2-butene initially added together with the reaction feed, and steam was introduced into the first reactor at a molar ratio based on the amount of 2-butene initially added together with the reaction feed. 5 was put in. Nitrogen and steam were mixed with the reaction feed and oxygen and introduced only in front of the first reactor.

The first reactor used a shell-and-tube reactor with an inner diameter of 2.54 cm, and the temperature inside the reactor was controlled by heating the heat-transfer salt filled in the outer jacket of the reactor with an electric furnace. The first reactor salt temperature was adjusted to 350°C.

The conditions of the first reactor were 350 ° C, GHSV = 250 h ^-1 , OBR = 0.47, SBR = 5, NBR = 1.87 (GHSV = Gas Hourly Space Velocity, OBR = Oxygen / total mixed-butene ratio, SBR = Steam / total mixed-butene ratio, NBR = Nitrogen/total mixed-butene ratio).

3) Heavy component removal reaction

The second reactor for removing heavy components in the first product formed by passing through the first reactor used a cylindrical shell-and-tube reactor having an inner diameter of 2.54 cm. The second reactor was filled with a catalyst in which Zn was supported on zeolite.

Oxygen was additionally introduced into the second reactor at a molar ratio of 0.4 based on the first product formed through the first reactor.

The second reactor used a shell-and-tube reactor with an inner diameter of 2.54 cm, and the temperature inside the reactor was controlled by heating the heat-transfer salt filled in the outer jacket of the reactor with an electric furnace. The second reactor salt temperature was adjusted to 250°C.

< Example 2>

In Example 1, the same procedure as in Example 1 was performed except that the wastewater of the product passing through the second reactor was recycled by inputting it to the first reactor.

< comparative example 1>

In Example 1, only the oxidative dehydrogenation process was performed in the first reactor without applying the second reactor.

< comparative example 2>

As shown in FIG. 2 below, in Example 1, the catalyst layer for oxidative dehydrogenation and the catalyst layer for removing heavy components were simultaneously filled in the first reactor without applying the second reactor.

< Experimental example >

In Examples 1 and 2 and Comparative Examples 1 and 2, the results of measuring butene conversion, butadiene selectivity, COx selectivity, heavy component selectivity, and hot spot are shown in Table 1 below.

[Table 1]

As the above result, when the heavy component is removed using the second reactor, the effect of improving selectivity can be obtained. In addition, as in Comparative Example 2, when the catalyst layer for oxidative dehydrogenation reaction and the catalyst layer for removing heavy components are simultaneously filled in the first reactor, it can be seen that the activity tends to decrease slightly.

In addition, as in Example 2, in an exemplary embodiment of the present application, activity reduction does not occur even when the generated wastewater is recycled, and thus, it is possible to reduce process costs by recycling the wastewater.

Therefore, according to an exemplary embodiment of the present application, by sequentially performing the first reactor process in which the oxidative dehydrogenation process is performed and the second reactor process in which the heavy component is removed, heavy components can be effectively removed, and the production of butadiene Selectivity can be improved. In addition, according to an exemplary embodiment of the present application, the load of the subsequent purification process may be reduced by including a second reactor process for removing heavy components.

In addition, according to an exemplary embodiment of the present application, COD (Chemical Oxygen Demand) of generated wastewater is low, and thus wastewater can be recycled to secure economic feasibility.

10: first catalyst layer for oxidative dehydrogenation reaction
20: second catalyst layer for the removal reaction of heavy components
30: reactant containing butene

Claims (11)

Injecting a reactant including butene and oxygen into a first reactor, and performing an oxidative dehydrogenation process in the first reactor; and
The first product formed through the first reactor and oxygen are introduced into a second reactor connected in series with the first reactor, and the first product formed through the first reactor is 1,3-butadiene, light components and heavy components, comprising removing the heavy components in the second reactor;
The process in the first reactor is carried out at a temperature of 330 ° C to 450 ° C,
The process in the second reactor is a method for producing 1,3-butadiene that is carried out at a temperature of 200 ℃ to 300 ℃. The method according to claim 1, wherein the reactant containing butene comprises a C4 mixture,
A method for producing 1,3-butadiene in which C4 mixture: oxygen is introduced into the first reactor at a molar ratio of 1: 0.4 to 0.6. The method for producing 1,3-butadiene according to claim 1, wherein the first product formed by passing through the first reactor to the second reactor:oxygen is introduced in a molar ratio of 1:0.3 to 0.5. The method according to claim 1, wherein the first reactor comprises a first catalyst layer for oxidative dehydrogenation reaction,
The first catalyst layer is a method for producing 1,3-butadiene comprising at least one of a bismuth-molybdenum-based catalyst and a ferrite-based catalyst. The method for preparing 1,3-butadiene according to claim 4, wherein the ferrite-based catalyst is represented by Formula 1 below:
[Formula 1]
AFe ₂ O ₄
In Formula 1, A is Cu, Ra, Ba, Sr, Ca, Be, Zn, Mg, Mn, Co or Ni. The method for producing 1,3-butadiene according to claim 4, wherein the bismuth-molybdenum-based catalyst is represented by Formula 2 below:
[Formula 2]
Mo _a Bi _b Fe _c Co _d E _e O _y
In Formula 2, E is at least one selected from among nickel, sodium, potassium, rubidium and cesium,
a, b, c, d and e are, when a is 10, b, c, d and e are 0.1 to 10, 0.1 to 10, 1 to 20, and 0 to 5, respectively;
y is a value determined to match the valency by other elements. The method according to claim 1, wherein the second reactor comprises a second catalyst layer for the removal reaction of heavy components present in the first product formed by passing through the first reactor,
The second catalyst layer is a method for producing 1,3-butadiene comprising a catalyst in which at least one metal of Cu, Mn, Ce, Zn, Fe and Zr is supported on zeolite. delete delete The method according to claim 1, wherein the light component includes at least one selected from hydrogen, oxygen, nitrogen, carbon dioxide, carbon monoxide, water vapor, methane, ethylene, acetaldehyde, 1-butene, 2-butene and vinylacetylene 1 Method for producing 3-butadiene. The method according to claim 1, wherein the heavy component is aldehyde, acrolein, furan, butanone, benzene, 4-vinyl cyclohexene, styrene, 4-formylcyclohexene, benzofuran, 3-acetyl-1-cyclohexene, cyclohexene di A method for producing 1,3-butadiene comprising at least one selected from carboxy, benzophenone and 9-fluorenone.