KR20200056316A - Device for producing methacrylic acid - Google Patents

Abstract

The present invention relates to an apparatus for producing methacrylic acid which shows excellent continuous operation ability. The apparatus (100) for producing methacrylic acid includes: a first reactor(10) for providing methacrolein; a second reactor (20) for providing methacrylic acid; a methacrolein recovery unit (70); a line (LA) for linking the outlet (10j) of the first reactor (10) with the inlet (20i) of the second reactor (20); a line (LB) for linking the line (LA) with an oxygen supplying source; a line (LC) for linking the outlet (20j) of the second reactor (20) with the liquid inlet (70i) of the methacrolein recovery unit (70); and a line (LD) for linking the gas outlet (70gi) of the methacrolein recovery unit (70) with the line (LA). Particularly, the line (LD) has a heating unit (23a), and the heating unit (23a) is disposed in at least a part of the site up to 30 from the gas outlet (70gi), when the length of the line from the gas outlet (70gi) to the junction (Xo) with the line (LA) is taken as 100.

Description

Manufacturing device for methacrylic acid {DEVICE FOR PRODUCING METHACRYLIC ACID}

The present invention relates to an apparatus for producing methacrylic acid.

Patent Document 1 describes a method for producing methacrylic acid.

International Publication No. 2008/145417

The manufacturing apparatus used for the production of methacrylic acid is required to be able to continuously operate over a long period of time. Therefore, it is an object of the present invention to provide an apparatus for producing methacrylic acid having excellent continuous operability.

The methacrylic acid production apparatus of the present invention has an inlet and an outlet, a first reactor for obtaining methacrolein from isobutylene and / or tert-butyl alcohol (hereinafter referred to as "TBA") and oxygen, A second reactor having an inlet and an outlet and obtaining methacrylic acid by reacting methacrolein and oxygen, a methacrolein recovery means having a liquid inlet, a liquid outlet and a gas outlet, and an outlet and a second reactor of the first reactor A line (LA) connecting the inlet of the line, a line (LB) connecting the line LA and the oxygen source, a line (LC) connecting the outlet of the second reactor and a liquid inlet of the methacrolein recovery means, A line LD connecting the gas outlet and the line LA of the methacrolein recovery means is provided, the line LD has heating means, and the heating means is connected to the line LA from the gas outlet ( When the length of the line up to Xo) is 100, it is arranged at least in part at a position from the gas outlet to 30.

The methacrylic acid production apparatus is excellent in continuous operability.

The said heating means may be arrange | positioned at least a part of the position from the said gas outlet to 20, or may be arrange | positioned at least a part of the position from the said gas outlet to 10. Thereby, continuous operability is further improved.

The length of the line from the gas outlet to the inlet of the heating means may be 3 m or less. Thereby, continuous operability is further improved.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing apparatus of methacrylic acid excellent in continuous operability can be provided.

1 is a view showing an example of an apparatus for producing methacrylic acid of the present embodiment.

In this specification, isobutylene refers to 2-methylpropene.

First, with reference to FIG. 1, the methacrylic acid manufacturing apparatus 100 which concerns on this embodiment is demonstrated. 1 is a view showing an example of an apparatus for producing methacrylic acid of the present embodiment.

The manufacturing apparatus 100 includes a first reactor 10, a second reactor 20, a liquefaction means 60, a methacrolein recovery means 70, and lines (LA, LB, LC, and LD). Mainly provided. Line LA has a gas mixer 50b. The line LB has a compressor 55. The line LD has heating means 23a.

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

The first reactor 10 is a reactor for obtaining methacrolein from isobutylene and / or TBA and oxygen. It is preferable that the 1st reactor 10 is a reactor filled with a catalyst in a container. The first reactor 10 may be a fixed bed reaction apparatus filled with a catalyst in a container. The direction of the flow is not limited, and may be an up flow or a down flow. Examples of catalysts used in the reaction for synthesizing methacrolein from isobutylene and / or TBA and oxygen are metal oxides containing molybdenum and bismuth.

When methacrolein is obtained from isobutylene and oxygen, isobutylene and oxygen react, thereby producing methacrolein. It is also possible to use TBA instead of isobutylene. When methacrolein is obtained from TBA and oxygen, it is thought that isobutylene is produced by dehydration reaction of TBA, and metachlorolane is produced by reaction of the produced isobutylene and oxygen. It is thought that the reason why TBA can be used instead of isobutylene is that in the first reactor 10, the oxidation reaction of isobutylene is at a rate. 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.

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

The second reactor 20 is a reactor for obtaining methacrylic acid by reacting methacrolein and oxygen. It is preferable that the second reactor 20 is a reactor filled with a catalyst in a vessel. The second reactor 20 may be a fixed bed reaction device filled with a catalyst in a container. There is no limitation in the direction of the flow, and it may be either upflow or downflow. Examples of catalysts used in the reaction for synthesizing methacrylic acid from methacrolein and oxygen are heteropoly acid compounds containing phosphorus and molybdenum.

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

The liquefaction means 60 is a means for liquefying methacrylic acid and unreacted methacrolein in the flow F30 of the outlet gas of the second reactor 20. The liquefaction means 60 may have a function of separating methacrolein. As the liquefaction means 60, for example, a distillation column, an extraction column, an absorption column, and combinations thereof can be mentioned. The number of inlets and outlets of the liquefaction means 60 can be changed depending on the form of the liquefaction means 60. For example, the line L35 and the line L31 may or may not exist. In addition, other lines not shown in the drawing may be connected to the liquefaction means 60.

The methacrolein recovery means 70 is a means for recovering methacrolein. The methacrolein recovery means 70 has a liquid inlet 70i, a liquid outlet 70j, and a gas outlet 70gj. The methacrolein recovery means 70 includes, for example, a dissipation column, a distillation column, and combinations thereof. In the defense tower, a liquid containing methacrolein is contacted with a dissipation gas to separate methacrolein by bringing methacrolein to the dissipation gas.

When the methacrolein recovery means 70 is a defense tower, the methacrolein recovery means 70 is added to the liquid inlet 70i, the liquid outlet 70j, and the gas outlet 70gj, as shown in FIG. 1. Likewise, it has a gas inlet 70gi. When the methacrolein recovery means 70 is a distillation column, the gas inlet 70gi is not necessarily required.

The gas outlet 70gj is preferably provided on the top of the tower of the methacrolein recovery means 70 from the viewpoint of easy to shorten the length of the line from the gas outlet 70gj to the inlet 23i of the heating means described later. Do. The liquid outlet 70j is provided on the bottom of the top of the methacrolein recovery means 70, for example.

A line L40 is connected to the liquid outlet 70j of the methacrolein recovery means 70. Line L40 joins line L31.

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

The heating means 23a is provided in a part of the line from the gas outlet 70gj to Xm. Here, when the length of the line from the gas outlet 70gj to the connection portion Xo with the line LA is 100, the length of the line from the gas outlet 70gj to Xm is 30 or less. That is, when the length of the line from the gas outlet 70gj to the connection part Xo with the line LA is 100, the heating means 23a is at least part of the position from the gas outlet 70gj to 30. Are deployed. Here, the length of the line means the length of the central axis of the line. Further, the heating means 23a is part of the line.

The heating means 23a is 20 from the gas outlet 70gj when the length of the line from the gas outlet 70gj to the connection portion Xo with the line LA is 100 from the viewpoint of further improving the continuous stability. It is preferable that it is arranged at least in part of the position up to, and it is more preferably arranged in at least part of the position from the gas outlet 70gj to 10.

Examples of the heating means 23a include a heat exchanger, a jacketed pipe, and a pipe wound around a sheet heater.

The length of the line from the gas outlet 70gj to the inlet 23i of the heating means 23a is preferably 3 m or less from the viewpoint of further improving continuous operability. The heating means 23a may be provided directly at the gas outlet 70gj. From the viewpoint of continuous stability and simplification of the apparatus, the gas outlet 70gj may be provided on the top of the methacrolein recovery means 70, and the heating means 23a may be provided directly on the gas outlet 70gj.

Next, the method for producing methacrylic acid according to the present embodiment will be described.

(Source)

A stream (F10) comprising isobutylene and / or TBA and oxygen as a source (S0) of gas containing isobutylene and / or TBA and oxygen is prepared.

Flow (F10) may contain components other than isobutylene, TBA, and oxygen. As components other than isobutylene, TBA and oxygen, for example, C5 olefins such as isoprene, isobutane, 1-butene, 2-butene (cis, trans), propane, propylene, n-butane, 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 flow (F10) is the sum of the concentrations 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 flow (F10) is, for example, 21% by mass or less, 19% by mass or less, or 17% by mass or less. The sum of the concentrations of isobutylene and TBA in the flow (F10) is preferably 1 to 21% by mass, more preferably 2 to 19% by mass, and still more preferably 4 to 17% by mass.

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

In addition, a flow F22 containing oxygen as the oxygen 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 flow 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 concentration of oxygen in the flow F22 can be, for example, 35% by mass. The concentration of oxygen in the flow F22 may be, for example, 30% by mass or less, or 25% by mass or less. The oxygen concentration in the flow F22 is preferably 16 to 35% by mass, more preferably 17 to 30% by mass, and even more preferably 18 to 25% by mass.

(Reaction process)

Flow (F10) is supplied to the first reactor (10), and isobutylene and oxygen in the flow (F10) are reacted in the first reactor (10). The flow (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 300 to 400 ° C. The reaction pressure of the first reactor 10 can be 0.004 to 0.6 MPaG (gauge pressure).

In the flow F11 discharged from the first reactor 10, a recycle flow F23 described later including methacrolein and dissipation gas is mixed via a line LD, and the line LB is interposed. The flow (F22) containing oxygen is mixed. Thereby, the obtained flow F21 is supplied to the 2nd reactor 20 via the line LA.

In the second reactor 20, methacrylic acid is obtained by reacting methacrolein and oxygen, and a flow F30 including methacrylic acid is discharged via a line LC.

The flow F30 contains unreacted methacrolein. The flow (F30) may contain components other than methacrylic acid and methacrolein. Examples of these 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, methylfurfural, acetic acid, and propionic acid. Can be.

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

(Liquefaction process)

The flow F30 exiting the second reactor 20 is provided to the liquefaction means 60 via a line LC. In the liquefaction means 60, methacrylic acid and methacrolein in the flow F30 are liquefied, and, for example, the flow F31 containing methacrylic acid and heavy components from the line L31 is a line ( From L35), a flow (F35) containing carbon monoxide, carbon dioxide, nitrogen, argon, and other light components and oxygen, and a flow (F34) containing methacrolein from line (LC) are extracted respectively. .

(Metacrolein recovery process)

The flow F34 containing methacrolein is provided to the methacrolein recovery means 70 via a line LC.

When the methacrolein recovery means 70 is a dissipation tower, the gas inlet 70gi supplies a flow containing a dissipation gas, and a flow F40 containing methacrylic acid and a heavy component from the liquid outlet 70j. , A flow F23 containing methacrolein and a dissipative gas is discharged from the gas outlet 70gj, respectively. The dissipation gas may be any gas capable of dissipating methacrolein when in contact with a liquid containing methacrolein. The dissipation gas may contain at least one kind of gas component selected from the group consisting of nitrogen, argon, oxygen and carbon dioxide.

When the methacrolein recovery means 70 is a distillation column, by a distillation operation, for example, a flow F40 containing methacrylic acid and heavy components from the liquid outlet 70j is meta from the gas outlet 70gj. The flows F23 including the crawl lanes may be discharged, respectively.

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

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

The flow F40 joins the flow F31.

The flow F23 is heated by the heating means 23a. The temperature of the flow F23 after heating may be 150 ° C or higher, 170 ° C or higher, or 190 ° C or higher, for example. The temperature of the flow F23 after heating may be 285 ° C or lower, 250 ° C or lower, or 220 ° C or lower, for example. The temperature of the flow F23 after heating may be, for example, 150 to 285 ° C, 170 to 250 ° C, or 190 to 220 ° C.

The flow F23 heated by the heating means 23a joins the flow F11 as a recycle flow.

The methacrylic acid production apparatus 100 has an inlet 10i and an outlet 10j, a first reactor 10 for obtaining methacrolein from isobutylene and / or TBA and oxygen, and an inlet 20i And a second reactor 20 having an outlet 20j and obtaining methacrylic acid by reacting methacrolein and oxygen, and a metacrole having a liquid inlet 70i, a liquid outlet 70j, and a gas outlet 70gj The line LA connecting the lane recovery means 70, the outlet 10j of the first reactor 10, and the inlet 20i of the second reactor 20, a line LA, and an oxygen source S1 A line LB connecting the line, an outlet 20j of the second reactor 20, and a line LC connecting the liquid inlet 70i of the metacrolein recovery means 70, and the metacrolein recovery means ( The gas outlet 70gj of 70 is provided with a line LD connecting the line LA, the line LD has a heating means, and the heating means is from the gas outlet 70gj to the connecting portion Xo. When the length of the line is set to 100, it is arranged at least part of the position from the gas outlet 70gj to 30. Thereby, the continuous operability is excellent. In such a device, the inventors speculate as to the reason why the continuous operability is excellent.

In the case of recycling the methacrolein recovered from the gas outlet of the methacrolein recovery means 70 to the second reactor, it is thought that if it is recycled at the same temperature, the methacrolein is liquefied and polymerized, or heavy components precipitate. do. And, if the continuous operation is continued as described above, the amount of methacrolein recycled from the methacrolein recovery means 70 to the second reactor is reduced, and as a result, there is a possibility that the productivity of methacrylic acid decreases. In addition, it is thought that the recycle amount of methacrolein affects the composition of the components at the inlet of the second reactor, and also affects the reaction in the second reactor. Accordingly, there is a possibility that continuous operation becomes difficult. On the other hand, the methacrylic acid production apparatus 100 is easy to reduce the precipitation of liquefaction and heavy components of methacrolein by providing heating means 23a at the above position of the line LD. 2 It is thought that it is easy to keep the reactor in a steady state. Therefore, even when driving for a long period of time, it is easy to stably operate and has excellent continuous operability.

In addition, the device of the present embodiment is considered to be capable of reducing raw materials and energy during long-term operation because of its excellent continuous operability.

The present invention is not limited to the above embodiments, and various modifications are possible.

For example, each of the first reactor 10 and the second reactor 20 may be a plurality of unit reactors connected in series or in parallel. Further, separate purification means such as a distillation column and an extraction column may be added to each line.

The line L40 does not necessarily have to join the line L31. That is, the flow F40 and the flow F31 may be sent separately to the next process.

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

In the methacrylic acid production apparatus 100, when the heating means 23a sets the length of the line from the gas outlet 70gj to the connection portion Xo with the line LA to 100, the gas outlet 70gj Although it is arrange | positioned in a part of the position from 30 to 30, the heating means may be arrange | positioned in all of the position from the gas outlet 70gj to 30.

The line LD may be further provided with other heating means at a place other than the position from the gas outlet 70gj to 30.

10… First reactor
20… Second reactor
50b… Gas mixer
60… Liquefaction means
70… Methacrolein recovery means
23a… Heating means
100… Methacrylic acid production equipment

Claims (4)

A first reactor having an inlet and an outlet and obtaining methacrolein from isobutylene and / or tert-butyl alcohol and oxygen,
A second reactor having an inlet and an outlet, and reacting methacrolein and oxygen to obtain methacrylic acid,
Methacrolein recovery means having a liquid inlet, a liquid outlet and a gas outlet,
A line (LA) connecting the outlet of the first reactor and the inlet of the second reactor,
A line LB connecting the line LA and an oxygen source,
A line (LC) connecting the outlet of the second reactor and the liquid inlet of the metacrolein recovery means,
And a line LD connecting the gas outlet of the metacrolein recovery means to the line LA,
The line LD has a heating means,
When the length of the line from the gas outlet to the connection part (Xo) with the line (LA) is 100, the heating means is disposed in at least a part of the position from the gas outlet to 30. Manufacturing equipment. According to claim 1,
The said heating means is arrange | positioned at least a part of the position from the said gas outlet to 20, The manufacturing apparatus of methacrylic acid. The method of claim 1 or 2,
The said heating means is arrange | positioned at least a part of the position from the said gas outlet to 10, The manufacturing apparatus of methacrylic acid. The method according to any one of claims 1 to 3,
A device for producing methacrylic acid, wherein the length of the line from the gas outlet to the inlet of the heating means is 3 m or less.

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