TW202024009A - Methacrylic acid production device - Google Patents

Abstract

Provided is a methacrylic acid production device which has excellent continuous workability. The methacrylic acid production device (100) is provided with: a first reactor (10) for obtaining methacrolein; a second reactor (20) for obtaining methacrylic acid; a methylacrolein recovery unit (70); a line (LA) connecting the outlet (10j) of the first reactor (10) and the inlet (20i) of the second reactor (20); a line (LB) connecting the line (LA) and the oxygen supply source; a line (LC) connecting the outlet (20j) of the second reactor (20) and the liquid inlet (70i) of the methylacrolein recovery unit (70); and a line (LD) connecting the gas outlet (70gj) of the methylacrolein recovery unit (70) and the line (LA). The line (LD) has a heating unit (23a) that is disposed on at least a portion of the line between the gas outlet (70gj) and a position where the line length is 30, where the line length from the gas outlet (70gj) to a connection portion (Xo) with the line (LA) is set as 100.

Description

Methacrylic acid manufacturing equipment

The invention relates to a methacrylic acid manufacturing device.

Patent Document 1 describes a method for producing methacrylic acid. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] International Publication No. 2008/145417

[The problem to be solved by the invention]

For the production equipment used to produce methacrylic acid, long-term continuous operation is required. Therefore, the object of the present invention is to provide an apparatus for producing methacrylic acid with excellent continuous operability. [Technical means to solve the problem]

The methacrylic acid production apparatus of the present invention includes: a first reactor having an inlet and an outlet, and methacrolein is obtained from isobutylene and/or tertiary butanol (hereinafter referred to as "TBA") and oxygen; and the second reaction Reactor, which has an inlet and an outlet to react methacrolein and oxygen to obtain methacrylic acid; a methacrolein recovery mechanism, which has a liquid inlet, a liquid outlet, and a gas outlet; line LA, which connects the first reactor The outlet and the inlet of the second reactor are connected; the line LB, which connects the line LA and the oxygen supply source; the line LC, which connects the outlet of the second reactor and the liquid inlet of the methacrolein recovery mechanism; and the line LD, It connects the gas outlet of the methacrolein recovery mechanism with the pipeline LA, and the pipeline LD has a heating mechanism. The heating mechanism is when the length of the pipeline from the gas outlet to the connection part Xo with the pipeline LA is set to 100, It is arranged at least part of the position from the gas outlet to 30.

This type of methacrylic acid production device is excellent in continuous operation.

The heating mechanism may also be arranged in at least a part of the position from the gas outlet to 20, or may be arranged in at least a part of the position from the gas outlet to 10. This further improves the continuous operability.

The length of the pipeline from the gas outlet to the inlet of the heating mechanism can be less than 3 m. This further improves the continuous operability. [Effects of Invention]

According to the present invention, it is possible to provide an apparatus for producing methacrylic acid with excellent continuous operability.

In this specification, the so-called isobutylene refers to 2-methylpropene.

First, referring to FIG. 1, the methacrylic acid production apparatus 100 of this embodiment will be described. Fig. 1 is a diagram showing an example of a methacrylic acid production apparatus of the present embodiment.

The manufacturing apparatus 100 mainly includes a first reactor 10, a second reactor 20, a liquefaction mechanism 60, a methacrolein recovery mechanism 70, and lines LA, LB, LC, and LD. The line LA is equipped with a gas mixer 50b. The line LB includes a compressor 55. The pipeline LD includes a heating mechanism 23a.

The inlet 10i of the first reactor 10 is connected via a line L10 to a supply source (S0) of a gas containing isobutylene and/or TBA and oxygen.

The first reactor 10 is a reactor for obtaining methacrolein from isobutylene and/or TBA and oxygen. The first reactor 10 is preferably a reactor filled with a catalyst in a container. The first reactor 10 may be a fixed bed reactor filled with a catalyst in the container. There is no restriction on the direction of flow, and it can be an upward flow or a downward flow. Examples of catalysts used in the reaction of synthesizing methacrolein from isobutylene and/or TBA and oxygen are metal oxides containing molybdenum and bismuth.

In the case of obtaining methacrolein from isobutylene and oxygen, the isobutylene reacts with oxygen, thereby generating methacrolein. TBA can also be used instead of isobutylene. It is thought that when methacrolein is obtained from TBA and oxygen, isobutene is produced by the dehydration reaction of TBA, and the produced isobutene reacts with oxygen to produce methacrolein. It is believed that the reason why TBA can be used instead of isobutylene is that in the first reactor 10, the oxidation reaction of isobutylene becomes a rate limitation. Isobutylene and TBA can also be used together.

The outlet 10j of the first reactor 10 and the inlet 20i of the second reactor 20 are connected by a line LA.

A pipeline LB is connected to the inlet 50b _m of the gas mixer 50b of the pipeline LA. The pipeline LB is a pipeline connecting the pipeline LA and the oxygen supply source (S1).

The second reactor 20 is a reactor for obtaining methacrylic acid by reacting methacrolein and oxygen. The second reactor 20 is preferably a reactor filled with a catalyst in a container. The second reactor 20 may be a fixed bed reactor filled with a catalyst in the container. The direction of flow is not limited, and it can be an upward flow or a downward flow. An example of the catalyst used in the reaction of synthesizing methacrylic acid from methacrolein and oxygen is a heteropolyacid compound containing phosphorus and molybdenum.

The outlet 20j of the second reactor 20 and the liquid inlet 70i of the methacrolein recovery mechanism 70 are connected by the line LC via the liquefaction mechanism 60. The liquefaction mechanism 60 has one inlet and three outlets. A pipeline LC is connected to the inlet and one outlet of the liquefaction mechanism 60, and a pipeline L35 and a pipeline L31 are respectively connected to the other two outlets.

The liquefaction mechanism 60 is a mechanism for liquefying methacrylic acid and unreacted methacrolein in the outlet gas flow (F30) of the second reactor 20. The liquefaction mechanism 60 may also have a function of separating methacrolein. As the liquefaction mechanism 60, a distillation tower, an extraction tower, an absorption tower, and the combination of these are mentioned, for example. The number of inlets and outlets of the liquefaction mechanism 60 can be changed according to the form of the liquefaction mechanism 60. For example, the pipeline L35 and the pipeline L31 are optional. In addition, other pipelines (not shown) may be connected to the liquefaction mechanism 60.

The methacrolein recovery mechanism 70 is a mechanism for recovering methacrolein. The methacrolein recovery mechanism 70 has a liquid inlet 70i, a liquid outlet 70j, and a gas outlet 70gj. Examples of the methacrolein recovery mechanism 70 include a stripping tower, a distillation tower, and a combination of these. In the stripping tower, the liquid containing methacrolein is brought into contact with the stripping gas, and the methacrolein is brought together with the stripping gas, thereby separating the methacrolein.

When the methacrolein recovery mechanism 70 is a stripping tower, the methacrolein recovery mechanism 70 has a gas inlet 70gi as shown in FIG. 1 in addition to a liquid inlet 70i, a liquid outlet 70j, and a gas outlet 70gj. When the methacrolein recovery mechanism 70 is a distillation tower, the gas inlet 70gi is not necessarily required.

Regarding the gas outlet 70gj, it is preferable to install it on the top of the tower of the methacrolein recovery mechanism 70 from the viewpoint of easily shortening the length of the pipeline from the gas outlet 70gj to the inlet 23i of the heating mechanism described below. The liquid outlet 70j is provided at the bottom of the methacrolein recovery mechanism 70, for example.

A line L40 is connected to the liquid outlet 70j of the methacrolein recovery mechanism 70. The pipeline L40 merges with the pipeline L31.

The gas outlet 70gj of the methacrolein recovery mechanism 70 and the line LA are connected by the line LD.

The heating mechanism 23a is installed in a part of the pipeline from the gas outlet 70gj to Xm. Here, when the length of the pipeline from the gas outlet 70gj to the connection part Xo with the pipeline LA is set to 100, the length of the pipeline from the gas outlet 70gj to Xm is 30 or less. That is, the heating mechanism 23a is arranged at least part of the position from the gas outlet 70gj to 30 when the length of the pipeline from the gas outlet 70gj to the connection part Xo with the pipeline LA is set to 100. Here, the length of the pipeline refers to the length of the central axis of the pipeline. In addition, the heating mechanism 23a is a part of the pipeline.

Regarding the heating mechanism 23a, from the viewpoint of further improving the continuous stability, when the length of the pipeline from the gas outlet 70gj to the connection part Xo with the pipeline LA is set to 100, it is preferably arranged from the gas outlet 70gj to At least a part of the position 20 is more preferably arranged at least a part of the position from 70gj to 10 of the gas outlet.

As the heating mechanism 23a, a heat exchanger, a jacketed pipe, a pipe wound with a sheet heater, etc. can be mentioned.

The length of the pipeline from the gas outlet 70gj to the inlet 23i of the heating mechanism 23a is preferably 3 m or less from the viewpoint of further improving the continuous operability. The heating mechanism 23a may also be directly installed in the gas outlet 70gj. From the viewpoint of continuous stability and simplification of the device, the gas outlet 70gj can also be arranged on the top of the methacrolein recovery mechanism 70 and the heating mechanism 23a can be directly arranged on the gas outlet 70gj.

Next, the manufacturing method of methacrylic acid of this embodiment is demonstrated.

(Source of supply) Prepare a stream (F10) containing isobutene and/or TBA and oxygen as a supply source (S0) of a gas containing isobutene and/or TBA and oxygen.

Stream (F10) may also contain components other than isobutylene, TBA, and oxygen. Examples of components other than isobutene, TBA and oxygen include C5 olefins such as isoprene, isobutane, 1-butene, 2-butene (cis, trans), propane, propylene, n-butane Alkane, methyl tert-butyl ether, methanol, dimethyl ether, butadiene, propadiene, diisobutylene, nitrogen, carbon monoxide, carbon dioxide, water and argon.

The concentration of isobutylene and/or TBA in the stream (F10) is calculated based on the total concentration of isobutylene and TBA, for example, 1% by mass or more, 2% by mass or more, or 4% by mass or more. The total concentration of isobutylene and TBA in the stream (F10) is, for example, 21% by mass or less, 19% by mass or less, or 17% by mass or less. The total concentration of isobutylene and TBA in the stream (F10) is preferably 1-21% by mass, more preferably 2-19% by mass, and still more preferably 4-17% by mass.

The oxygen concentration in the flow (F10) is, for example, 7 mass% or more, 8 mass% or more, or 10 mass% or more. The oxygen concentration in the flow (F10) is, for example, 24% by mass or less, 23% by mass or less, or 21% by mass or less. The oxygen concentration in the flow (F10) is preferably 7 to 24% by mass, more preferably 8 to 23% by mass, and still more preferably 10 to 21% by mass.

In addition, a stream (F22) containing oxygen as an oxygen supply source (S1) is prepared.

The concentration of oxygen in the flow (F22) is, for example, 15% by mass or more. The concentration of oxygen in the stream (F22) is preferably 16% by mass or more, more preferably 17% by mass or more, and still more preferably 20% by mass or more. The upper limit of the oxygen concentration in the flow (F22) can be set to 35% by mass, for example. The concentration of oxygen in the stream (F22) may be 30% by mass or less, or 25% by mass or less, for example. The oxygen concentration in the stream (F22) is preferably 16 to 35% by mass, more preferably 17 to 30% by mass, and still more preferably 18 to 25% by mass.

(Reaction step) The stream (F10) is supplied to the first reactor 10, and in the first reactor 10, isobutene and oxygen in the stream (F10) are reacted. The stream (F11) containing methacrolein obtained by the reaction of isobutylene and oxygen is discharged from the line LA.

The reaction temperature of the first reactor 10 can be set at 300-400°C. The reaction pressure of the first reactor 10 can be set to 0.004 to 0.6 MPaG (gauge pressure).

In the stream (F11) discharged from the first reactor 10, the following recovered stream (F23) containing methacrolein and stripping gas is mixed through line LD, and the stream (F22) containing oxygen is mixed through line LB . Thereby, the obtained stream (F21) is supplied to the second reactor 20 via the line LA.

In the second reactor 20, methacrolein and oxygen are reacted to obtain methacrylic acid, and the stream (F30) containing methacrylic acid is discharged through line LC.

Stream (F30) contains unreacted methacrolein. The stream (F30) may contain components other than methacrylic acid and methacrolein. Examples of such components include acrylic acid, acrolein, nitrogen, argon, water, carbon monoxide, carbon dioxide, acetaldehyde, propionaldehyde, terephthalic acid, maleic acid, fumaric acid, diacetyl, isophthalic acid , Isobutyric acid, methyl furfural, acetic acid, propionic acid, etc.

The reaction temperature of the second reactor 20 can be set at 200-350°C. The reaction pressure in the second reactor 20 is, for example, 0.01 to 0.3 MPaG.

(Liquefaction step) The stream (F30) flowing out of the second reactor 20 is supplied to the liquefaction mechanism 60 via the line LC. In the liquefaction mechanism 60, methacrylic acid and methacrolein in the stream (F30) are liquefied, for example, a stream (F31) containing methacrylic acid and heavy components is extracted from a line L31, and a stream (F31) containing carbon monoxide, The flow of carbon dioxide, nitrogen, argon, other light components and oxygen (F35) is drawn from the line LC containing the flow of methacrolein (F34).

(Methacrolein recovery step) The stream (F34) containing methacrolein is supplied to the methacrolein recovery mechanism 70 via the line LC.

When the methacrolein recovery mechanism 70 is a stripping tower, a stream containing stripping gas is supplied to the gas inlet 70gi, and a stream containing methacrylic acid and heavy components is discharged from the liquid outlet 70j (F40) from the gas outlet 70gj discharge the stream (F23) containing methacrolein and stripping gas. The stripping gas only needs to be a gas capable of stripping methacrolein when it comes into contact with a liquid containing methacrolein. The stripping gas may also include at least one gas component selected from the group consisting of nitrogen, argon, oxygen, and carbon dioxide.

When the methacrolein recovery mechanism 70 is a distillation tower, the distillation operation is required, for example, a stream containing methacrylic acid and heavy components (F40) is discharged from the liquid outlet 70j, and a stream containing methacrylic acid is discharged from the gas outlet 70gj. Aldehyde flow (F23) is fine.

The temperature of the flow (F23) at the gas outlet 70gj of the methacrolein recovery mechanism 70 may be 50-90°C, 55-85°C, or 60-80°C, for example.

The concentration of methacrolein in the stream (F23) is preferably 0.1% by mass or more, more preferably 3% by mass or more, and still more preferably 7% by mass or more. The concentration of methacrolein in (F23) is preferably 32% by mass or less, more preferably 23% by mass or less, and still more preferably 16% by mass or less. The concentration of methacrolein in the stream (F23) can be 0.1 to 32% by mass, 3 to 23% by mass, or 7 to 16% by mass. The stream (F23) may contain nitrogen, argon, oxygen, water, and carbon dioxide as components other than methacrolein, for example.

Flow (F40) merges with flow (F31).

The flow (F23) is heated by the heating mechanism 23a. The temperature of the heated stream (F23) can be, for example, 150°C or higher, 170°C or higher, or 190°C or higher. The temperature of the heated stream (F23) can be, for example, 285°C or lower, 250°C or lower, or 220°C or lower. The temperature of the heated stream (F23) can be, for example, 150-285°C, 170-250°C, or 190-220°C.

The flow (F23) heated by the heating mechanism 23a is merged with the flow (F11) as a recovery flow.

The methacrylic acid production apparatus 100 includes: a first reactor 10 having an inlet 10i and an outlet 10j to obtain methacrolein from isobutylene and/or TBA and oxygen; and a second reactor 20 having an inlet 20i and an outlet 20j , Reacting methacrolein and oxygen to obtain methacrylic acid; methacrolein recovery mechanism 70, which has a liquid inlet 70i, a liquid outlet 70j, and a gas outlet 70gj; line LA, which connects the outlet 10j of the first reactor 10 And the inlet 20i of the second reactor 20; line LB, which connects the line LA and the oxygen supply source (S1); line LC, which connects the outlet 20j of the second reactor 20 and the liquid of the methacrolein recovery mechanism 70 The inlet 70i is connected; and the pipeline LD, which connects the gas outlet 70gj of the methacrolein recovery mechanism 70 with the pipeline LA, and the pipeline LD has a heating mechanism, which is connected to the pipeline from the gas outlet 70gj to the connection part Xo When the length is set to 100, it is arranged at least part of the position from 70gj to 30 of the gas outlet. This provides excellent continuous operation. In such a device, the inventors have estimated the reason for the excellent continuous operability as follows.

When the methacrolein recovered from the gas outlet of the methacrolein recovery mechanism 70 is recovered in the second reactor, it is considered that if the recovery is carried out directly at the temperature of this state, the methacrolein is liquefied and polymerized. Or focus on quality analysis. In addition, if the continuous operation is continued directly, the amount of methacrolein recovered from the methacrolein recovery mechanism 70 in the second reactor may decrease, and as a result, the productivity of methacrylic acid may decrease. It is also believed that the amount of methacrolein recovered will affect the composition of the composition at the entrance of the second reactor, and therefore will also affect the reaction in the second reactor. Along with this, there is also the possibility of making continuous operation difficult. In view of this, it is believed that the methacrylic acid production apparatus 100 is equipped with a heating mechanism 23a at the above-mentioned position of the line LD, which can easily reduce the liquefaction of methacrolein and the precipitation of heavy components, so that the second reactor can be easily kept stable. status. Therefore, even in the case of long-term operation, stable operation is easy, and continuous operation is excellent.

In addition, since the device of this embodiment is excellent in continuous operation, it is considered that the raw materials and energy during long-term operation can be reduced.

The present invention is not limited to the above-mentioned embodiments, and can be variously modified.

For example, the first reactor 10 and the second reactor 20 may be formed by connecting a plurality of unit reactors in series or in parallel, respectively. In addition, separation and purification mechanisms such as distillation towers and extraction towers may be added to each pipeline.

The line L40 does not need to merge with the line L31. That is, the stream (F40) and the stream (F31) may be sent to the next step separately.

The gas mixer 50b can also be omitted. In this case, the pipeline LB can be directly connected to the piping of the pipeline LA.

In the methacrylic acid production device 100, the heating mechanism 23a is arranged at a part of the position from the gas outlet 70gj to 30 when the length of the pipeline from the gas outlet 70gj to the connection part Xo with the pipeline LA is set to 100 , But the heating mechanism can also be arranged in all positions from 70gj to 30 of the gas outlet.

The pipeline LD may also be provided with other heating mechanisms at locations other than the position from the gas outlet 70gj to 30.

10: first reactor 10i: inlet 10j: outlet 20: second reactor 20i: inlet 20j: outlet 23a: heating mechanism 23i: inlet 50b: gas mixer 50b _m : inlet 55: compressor 60: liquefaction mechanism 70: Methacrolein recovery mechanism 70gi: gas inlet 70gj: gas outlet 70i: liquid inlet 70j: liquid outlet 100: methacrylic acid manufacturing device F10: flow F11: flow F21: flow F22: flow F23: flow F30: flow F31: Flow F34: Flow F35: Flow F40: Flow L10: Pipeline L31: Pipeline L35: Pipeline L40: Pipeline LA: Pipeline LB: Pipeline LC: Pipeline LD: Pipeline S0: Gas Supply Source S1: Oxygen Supply Source Xo: Connection Part

Fig. 1 is a diagram showing an example of a methacrylic acid production apparatus of the present embodiment.

10: The first reactor

10i: entrance

10j: export

20: second reactor

20i: entrance

20j: export

23a: heating mechanism

23i: entrance

50b: Gas mixer

50b _m : entrance

55: Compressor

60: Liquefaction Mechanism

70: Methacrolein recycling agency

70gi: gas inlet

70gj: gas outlet

70i: Liquid inlet

70j: Liquid outlet

100: Manufacturing equipment for methacrylic acid

F10: Stream

F11: Stream

F21: Stream

F22: Stream

F23: Stream

F30: flow

F31: Stream

F34: Stream

F35: Stream

F40: Stream

L10: pipeline

L31: pipeline

L35: pipeline

L40: pipeline

LA: pipeline

LB: pipeline

LC: pipeline

LD: pipeline

S0: gas supply source

S1: oxygen supply source

Xo: Connection part

Claims (4)

A manufacturing device for methacrylic acid, comprising: a first reactor having an inlet and an outlet, and obtaining methacrolein from isobutylene and/or tertiary butanol and oxygen; The second reactor has an inlet and an outlet to react methacrolein and oxygen to obtain methacrylic acid; A methacrolein recovery mechanism, which has a liquid inlet, a liquid outlet and a gas outlet; Line LA, which connects the outlet of the first reactor and the inlet of the second reactor; The pipeline LB, which connects the aforementioned pipeline LA and the oxygen supply source; Line LC, which connects the outlet of the second reactor and the liquid inlet of the methacrolein recovery mechanism; and A pipeline LD, which connects the gas outlet of the methacrolein recovery mechanism to the pipeline LA, and The above-mentioned pipeline LD has a heating mechanism, The heating mechanism is arranged at least part of the position from the gas outlet to 30 when the length of the pipeline from the gas outlet to the connection part Xo with the pipeline LA is set to 100. The methacrylic acid manufacturing device of claim 1, wherein the heating mechanism is arranged at least part of the position from the gas outlet to 20. The methacrylic acid manufacturing device of claim 1 or 2, wherein the heating mechanism is arranged at least part of the position from the gas outlet to 10. The methacrylic acid production device of any one of claims 1 to 3, wherein the length of the pipeline from the gas outlet to the inlet of the heating mechanism is 3 m or less.

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