TWI774969B - Method for producing methacrolein and/or methacrylic acid - Google Patents

Abstract

The present invention provides a method for producing methacrolein and/or methacrylic acid having excellent selectivity of methacrolein and/or methacrylic acid. The present invention relates to a method for producing methacrolein and/or methacrylic acid, which comprises the steps of mixing an oxygen-containing gas with a gas containing at least one of isobutylene and tertiary butanol to obtain a mixed gas, and The step of supplying the above-mentioned mixed gas to a reactor equipped with an oxidation catalyst at a temperature of 100 to 200°C.

Description

Method for producing methacrolein and/or methacrylic acid

The present invention relates to a method for producing methacrolein and/or methacrylic acid.

As a method for producing methacrolein and/or methacrylic acid, for example, a method using isobutylene is known (for example, refer to Patent Documents 1 to 4). [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2002-53519 [Patent Document 2] Japanese Patent Laid-Open No. 2005-314314 [Patent Document 3] Japanese Patent Laid-Open No. 2004-277339 [Patent Document 4] Japanese Patent Publication No. 60-25195

[Problems to be Solved by Invention]

In the production method of methacrolein and/or methacrylic acid, it is required to obtain methacrolein and/or methacrylic acid with high selectivity. Therefore, the objective of this invention is to provide the manufacturing method of methacrolein and/or methacrylic acid which can manufacture methacrolein and/or methacrylic acid with excellent selectivity. [Technical means to solve problems]

The method for producing methacrolein and/or methacrylic acid of the present invention includes the steps of mixing an oxygen-containing gas and a gas containing at least one of isobutylene and tertiary butanol to obtain a mixed gas, and mixing the above The step of supplying the gas to a reactor equipped with an oxidation catalyst at a temperature of 100 to 200°C.

According to the above method, methacrolein and/or methacrylic acid can be produced with excellent selectivity.

In the above method, preferably the step of obtaining the mixed gas comprises: the step of diluting the oxygen-containing gas with a diluent gas, and adding the diluted oxygen-containing gas to a gas containing at least one of isobutylene and tertiary butanol. mixing steps.

According to the above method, the selectivity of methacrolein and/or methacrylic acid can be further improved.

In the above method, it is preferable that the reactor is provided with a packed layer of oxidation catalyst, the temperature of the mixed gas supplied to the reactor is lower than the temperature of the gas at the outlet of the packed layer, and the temperature of the gas at the outlet is different from that of the mixed gas supplied to the reactor. The difference in temperature is 120°C or more.

According to the above method, the selectivity of methacrolein and/or methacrylic acid can be further improved.

In the above method, it is preferable that the reactor is provided with a packed layer of an oxidation catalyst and a temperature adjustment mechanism for supplying a heat medium to the reactor to adjust the temperature of the packed layer, and the temperature of the mixed gas supplied to the reactor is lower than that supplied to the reactor. The temperature of the heat medium, the difference between the temperature of the heat medium supplied to the reactor and the temperature of the mixed gas supplied to the reactor is 120°C or more.

According to the above method, the selectivity of methacrolein and/or methacrylic acid can be further improved. [Effect of invention]

According to the present invention, a method for producing methacrolein and/or methacrylic acid capable of producing methacrolein and/or methacrylic acid with excellent selectivity can be provided.

In this specification, isobutene refers to 2-methylpropene.

Hereinafter, a method for producing methacrolein and/or methacrylic acid according to one embodiment of the present invention will be described. First, with reference to FIG. 1, the manufacturing apparatus 100 of methacrolein and/or methacrylic acid of this embodiment is demonstrated.

The manufacturing apparatus 100 includes: a supply source of a gas (hereinafter also referred to as a “raw material gas”) containing at least one of isobutylene and tertiary butanol (also referred to as “TBA”), a supply source of an oxygen-containing gas, and water The supply source of steam, the gas mixer 50 a , the first reactor 10 , the second reactor 20 , the separation mechanism 60 , the gas combustion mechanism 80 , the temperature adjustment mechanism 52 , the gas mixer 50 b , and the compressor 55 .

The supply source of the raw material gas and the supply source of the oxygen-containing gas are connected to the gas mixer 50a via the line L2 and the line L1, respectively. A supply source of water vapor is connected to line L1 via line L4. The gas mixer 50a is connected to the first reactor 10 via the line L10.

The first reactor 10 is connected to the second reactor 20 via line L21. A gas mixer 50b is provided in the line L21, and the supply source of oxygen is connected to the gas mixer 50b via the compressor 55 and the line L22.

The second reactor 20 is connected to the separation mechanism 60 via the line L30. The line L35 is connected to the upper part of the separation mechanism 60, the line L31 is connected to the lower part, and the line L23 is connected to the side surface. Line L23 is connected to line L21 at a position between the first reactor 10 and the gas mixer 50b. The line L35 is connected to the gas combustion mechanism 80 . The gas combustion mechanism 80 is connected to the temperature adjustment mechanism 52 via the line L38, and the temperature adjustment mechanism 52 is connected to the line L1 via the line L3. The connecting portion of the line L3 and the line L1 is the position between the connecting portion of the line L1 and the line L4 and the supply source of the oxygen-containing gas.

The first reactor 10 includes a supply line L101 for the heat medium and a discharge line L102 for the heat medium. The first reactor 10 includes an oxidation catalyst. Examples of the oxidation catalyst include metal oxides containing molybdenum and bismuth.

The first reactor 10 is preferably a reactor filled with an oxidation catalyst in a vessel. That is, the first reactor 10 is preferably provided with a packed layer of an oxidation catalyst (hereinafter also referred to as a "catalyst packed layer"). The first reactor 10 may be a fixed-bed reaction device filled with an oxidation catalyst in the vessel. Moreover, it is preferable that the 1st reactor 10 is provided with the temperature adjustment mechanism which supplies a heat medium to the 1st reactor 10, and adjusts the temperature of a catalyst filling layer. The first reactor 10 may be a multi-tubular tubular reactor equipped with the above-mentioned temperature adjustment mechanism. The direction of the heat medium and the reaction flow is unlimited, and it can be an upward flow or a downward flow.

An example of the separation mechanism 60 is a distillation column.

The gas burning mechanism 80 is a device for burning gas. The gas combustion mechanism 80 may also include a catalyst.

An example of the temperature adjustment mechanism 52 is a heat exchanger.

The second reactor 20 includes a supply line L103 for the heat medium and a discharge line L104 for the heat medium. The second reactor 20 is provided with an oxidation catalyst. As this oxidation catalyst, a heteropolyacid compound containing phosphorus and molybdenum is mentioned, for example.

The second reactor 20 is preferably a reactor filled with an oxidation catalyst in a vessel. The second reactor 20 may be a fixed-bed reaction device filled with an oxidation catalyst in the vessel. The second reactor 20 is preferably a multi-tubular tubular reactor with a temperature adjustment mechanism. The directions of the heat medium and the reaction flow are not limited, and they can be an upward flow or a downward flow, respectively. That is, the flow direction of the heat medium and the reaction flow may be any of convection, advection, and cross-flow.

Next, the manufacturing method of the methacrolein and/or methacrylic acid of this embodiment is demonstrated.

(supply source) First, the flow (F2) of the raw material gas as the supply source of the raw material gas is prepared. Furthermore, a flow (F0) of the oxygen-containing gas as a supply source of the oxygen-containing gas and a flow (F4) of the water vapor as a supply source of the water vapor are prepared.

Stream (F2) may also contain components other than isobutene and TBA. Examples of components other than isobutylene and TBA include C5 olefins such as isoprene, isobutane, 1-butene, propane, propylene, n-butane, methyl tertiary butyl ether, methanol, and dimethyl ether. ether and butadiene.

The concentration of isobutene and/or TBA in the flow (F2) is preferably 85 to 99.99 mass %, more preferably 90 to 99.95 mass %, and still more preferably 95 to 99.94 mass %, based on the total concentration of isobutene and TBA.

Stream (F0) may also contain components other than oxygen. Examples of components other than oxygen include nitrogen, carbon dioxide, carbon monoxide, water vapor, and argon.

The oxygen concentration in the flow (F0) is preferably 15-25 vol%, more preferably 16-23 vol%, and still more preferably 18-22 vol%. An example of an oxygen-containing gas is air.

Water vapor mainly contains water.

(mixing step) Next, the flow (F0) of the oxygen-containing gas and the flow (F2) of the raw material gas are supplied to the gas mixer 50a through the line L1 and the line L2, respectively. The flow (F3) of the combustion gas (diluent gas) is supplied to the line L1 via the line L3, and the flow (F4) of the water vapor (diluent gas) is supplied to the line L1 via the line L4, thereby diluting by the combustion gas and the water vapor Oxygen-containing gas. That is, after mixing the flow of oxygen-containing gas (F0) and the flow of combustion gas (F3) to obtain a flow (F1) containing oxygen and combustion gas, the flow of water vapor (F4) and the flow of raw gas (F2) ) are sequentially mixed in the flow (F1) to obtain the flow (F10) of the mixed gas.

The combustion gas may contain nitrogen, carbon dioxide and water, for example. The combustion gas may further contain other components such as carbon monoxide and argon, for example.

The concentration of isobutene and/or TBA in the mixed gas flow (F10) is, for example, 0.5 vol% or more, 1 vol% or more, or 2 vol% or more based on the total concentration of isobutene and TBA. The above-mentioned concentration is, for example, 10 vol % or less, 9 vol % or less, or 8 vol % or less based on the total concentration of isobutylene and TBA. The above-mentioned concentration is preferably 0.5 to 10% by volume, more preferably 1 to 9% by volume, and still more preferably 2 to 8% by volume based on the total concentration of isobutene and TBA.

The oxygen concentration in the flow (F10) is, for example, 6 vol % or more, 7 vol % or more, or 8 vol % or more. The oxygen concentration in the mixed gas is, for example, 20 vol % or less, 16 vol % or less, or 15 vol % or less. The oxygen concentration in the flow (F10) is preferably 6 to 20% by volume, more preferably 7 to 16% by volume, and still more preferably 8 to 15% by volume.

The flow (F10) may contain other components such as nitrogen, water, and carbon dioxide in addition to the above-mentioned components.

Thus, by including the step of diluting the oxygen-containing gas with the diluent gas, and the step of mixing the diluted oxygen-containing gas with a gas comprising at least one of isobutylene and tertiary butanol, methacrylic acid can be further improved Aldehyde and/or methacrylic acid selectivity.

(supply step) Next, the flow (F10) of the mixed gas is supplied to the first reactor 10 via the line L10. The supply temperature of the mixed gas to the first reactor 10 is 100 to 200°C. From the viewpoint of the conversion rate of isobutene, the temperature is preferably 105°C or higher, more preferably 110°C or higher, and still more preferably 115°C or higher. From the viewpoint of the selectivity of methacrolein and/or methacrylic acid, the temperature is preferably 195°C or lower, more preferably 190°C or lower, and still more preferably 185°C or lower.

The supply temperature of the mixed gas to the first reactor 10 can be adjusted, for example, by compressing the flow (F0) of the oxygen-containing gas by a blower; adjusting the temperature and flow rate of the flow (F4) of water vapor; The flow (F3) of the combustion gas (diluent gas) is compressed by the blower; the temperature of the flow (F3) is adjusted by the temperature adjustment mechanism 52; and the flow rate of the flow (F3) is adjusted. Moreover, you may provide temperature adjustment means, such as a heat exchanger, in line L10, line L1, etc.,.

(reaction step) In the first reactor 10, methacrolein is produced from isobutene and/or TBA in stream (F10), and a stream (F11) comprising methacrolein is withdrawn via line L21.

When the stream (F2) of the raw material gas contains isobutene, the isobutene reacts with oxygen in the first reactor 10, thereby producing methacrolein.

TBA can also be used in place of isobutene. In this case, methacrolein is generated from TBA and oxygen. As a specific reaction mechanism, isobutene is produced by the dehydration reaction of TBA, and the produced isobutene reacts with oxygen to produce methacrolein. The reason for thinking that TBA can be used in place of isobutene is that within the first reactor 10, the oxidation of isobutene is the rate-determining step. Isobutylene and TBA can also be used together.

Stream (F11) may contain components other than methacrolein. As such a component, for example, methacrylic acid, acrolein, acetone, acetaldehyde, propionaldehyde, terephthalic acid, maleic acid, fumaric acid, diacetyl, isophthalic acid, Isobutyric acid, methyl furfural, acetic acid, acrylic acid and propionic acid.

The temperature of the flow (F11) at the outlet of the first reactor 10 is usually 250-400°C, preferably 255-380°C, more preferably 260-360°C, and further preferably 265-350°C.

From the viewpoint of the selectivity of methacrolein and/or methacrylic acid, the difference between the gas temperature at the outlet of the catalyst packed layer of the first reactor 10 and the supply temperature of the mixed gas to the first reactor 10 (The catalyst filling layer outlet temperature-mixed gas supply temperature) is preferably 120°C or higher, more preferably 130°C or higher, and still more preferably 140°C or higher. The difference between the outlet temperature of the catalyst filled layer and the supply temperature of the mixed gas can be, for example, 300° C. or less. The gas temperature at the outlet of the catalyst filling layer can be adjusted, for example, by the temperature of the heat medium. The flow out of the catalyst pack may also be cooled by a cooling zone before being discharged from the first reactor 10 .

Furthermore, when the first reactor 10 is provided with a catalyst-filled layer and a temperature adjustment mechanism for supplying a heat medium to the first reactor 10 to adjust the temperature of the catalyst-filled layer, methacrolein and/or methyl From the viewpoint of the selectivity of acrylic acid, the difference between the temperature of the heat medium supplied to the first reactor 10 and the temperature of the mixed gas supplied to the first reactor 10 (heat medium temperature - mixed gas supply temperature) is preferably 120 °C or higher, more preferably 130°C or higher, still more preferably 140°C or higher. The difference between the heat medium temperature and the mixed gas supply temperature can be, for example, 300° C. or less.

The reaction pressure in the first reactor 10 is usually 0.004-0.6 MPaG (gauge pressure), preferably 0.006-0.5 MPaG, more preferably 0.008-0.4 MPaG, and still more preferably 0.01-0.3 MPaG.

For the stream (F11) discharged from the first reactor 10, after mixing the recycle stream (F23) containing methacrolein via line L23, the stream (F22) of oxygen-containing gas is mixed via line L22. Then, the obtained stream (F21) is fed to the second reactor 20 via line L21. The supply source of the oxygen-containing gas used by the flow (F22) can be, for example, the supply source of the flow (F0).

In the second reactor 20, methacrylic acid is generated from the methacrolein in the stream (F21), and a stream (F30) containing methacrylic acid is discharged via line L30.

Stream (F30) contains unreacted methacrolein. Stream (F30) may contain ingredients other than methacrylic acid and methacrolein. Examples of such components include acrylic acid, acrolein, carbon monoxide, acetaldehyde, propionaldehyde, terephthalic acid, maleic acid, fumaric acid, diacetate, isophthalic acid, and isobutylene. acid, methyl furfural, acetic acid and propionic acid.

The supply temperature of the flow (F21) to the second reactor 20 is, for example, 200 to 350°C. Moreover, the temperature of the flow (F30) at the exit of the second reactor 20 is, for example, 250 to 350°C. The reaction pressure in the second reactor 20 is, for example, 0.01 to 0.3 MPaG.

(Separation step and circulation step) The flow (F30) flowing out of the second reactor 20 is supplied to the separation mechanism 60 via the line L30. In the separation mechanism 60, a flow (F35) containing carbon monoxide, light components and oxygen is extracted from the upper part through the pipeline L35, and a flow containing methacrylic acid and heavy components is extracted from the lower part through the pipeline L31 (F31), Line L23 draws from the side a stream (F23) comprising methacrolein.

The flow ( F35 ) is supplied to the gas combustion mechanism 80 . In the gas combustion mechanism 80, one of the carbon oxides and light components in the flow (F35) is combusted by the oxygen in the flow, thereby converting these into carbon dioxide. After the flow after combustion (F38) is extracted by L38, the temperature is adjusted by the temperature adjustment mechanism 52. The temperature-adjusted flow is circulated through line L3 as a flow (F3) of combustion gas (diluent gas).

Also, the stream (F23) containing methacrolein is recycled to L21 via line L23.

The production method of the present embodiment includes: a step (mixing step) of obtaining a mixed gas by mixing an oxygen-containing gas with a gas containing at least one of isobutylene and tertiary butanol, and heating the mixed gas at 100 to 200° C. The step of supplying it to a reactor equipped with an oxidation catalyst at the temperature (supplying step).

The reaction temperature in the first reactor 10 is usually about 350°C. From the viewpoint of efficiently raising the temperature in the first reactor 10 to the reaction temperature, the supply temperature of the mixed gas to the first reactor 10 is considered to be, for example, about 350°C. However, in this method, the selectivity of methacrolein and/or methacrylic acid is insufficient. On the other hand, according to the production method of the present embodiment, methacrolein and/or methacrylic acid can be produced with excellent selectivity.

The reaction in the first reactor 10 is an exothermic reaction. From the viewpoint of reducing temperature unevenness in the reactor, it is considered to reduce the difference between the gas temperature at the outlet of the catalyst packed layer and the supply temperature of the mixed gas to the first reactor 10 (the catalyst packed layer outlet temperature − mixed gas supply temperature). In this case, it is considered that the mixed gas is supplied at a temperature close to the outlet temperature of the catalyst filling layer, and the temperature of the filling layer is adjusted by a heat medium. However, as described above, the difference between the outlet temperature of the catalyst filling layer and the supply temperature of the mixed gas is preferably 120° C. or more. In addition, the difference between the temperature of the heat medium for temperature adjustment of the filling layer and the supply temperature of the mixed gas is preferably 120° C. or more. Thereby, the selectivity of methacrolein and/or methacrylic acid is further improved.

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

For example, separation and purification mechanisms such as a distillation column and an extraction column may be further added to each line. The separation mechanism 60 can also be a draw column or a combination of a distillation column and a draw column.

In the above-described embodiment, the supply temperature of the mixed gas is adjusted by the steam and the temperature adjustment mechanism 52, but a temperature adjustment mechanism such as a heat exchanger may be provided between the gas mixer 50a and the first reactor 10 instead of this Wait.

The line L3 and the line L4 may be present or not, and may be either. That is, the dilution gas may be any one of combustion gas and water vapor, and the step of diluting with the dilution gas may be omitted. In addition, the supply order of the flow of combustion gas (F3) and the flow of water vapor (F4) may be reversed. Instead of the pipeline L3 and the pipeline L4, a supply pipeline of the diluent gas may be additionally provided. [Example]

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to these Examples.

(Preparation of Oxidation Catalyst) The catalyst Ia is adjusted by the following steps 1 to 4.

[Step 1] Preparation of calcined body A liquid was obtained by dissolving 13,241 g of ammonium molybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ ·4H ₂ O] in 15,000 g of warm water.

6060 g of iron(III) nitrate [Fe(NO ₃ ) ₃・9H ₂ O], 13096 g of cobalt nitrate [Co(NO ₃ ) ₂・6H ₂ O], and 585 g of cesium nitrate [CsNO ₃ ] were dissolved in the temperature. In the solution obtained in 6000 g of water, 2910 g of bismuth nitrate [Bi(NO ₃ ) ₃ ·5H ₂ O] was further dissolved to obtain B liquid.

A slurry was obtained by adding liquid B to liquid A while stirring liquid A. The obtained slurry was dried by an air flow dryer to obtain a dried product. A mixture of 100 parts by mass of the obtained dried product, 9 parts by mass of silica-alumina fibers (manufactured by Saint-Gobain TM, trade name RFC400-SL) and 2.5 parts by mass of antimony trioxide (Sb ₂ O ₃ ) was formed into an outer diameter. After a ring of 6.3 mm, inner diameter of 2.5 mm, and length of 6 mm, it was calcined at 545° C. for 6 hours under an air flow.

The calcined body obtained by calcination contained 0.96 atoms of bismuth, 2.4 atoms of iron, 7.2 atoms of cobalt, 0.48 atoms of cesium, and 0.48 atoms of antimony with respect to 12 atoms of molybdenum.

[Step 2] Restoration processing After filling 75 mL of the calcined body obtained in step 1 in a glass tube, a mixed gas of hydrogen/nitrogen=5/95 (volume ratio) was supplied at a flow rate of 300 mL/min, and reduction treatment was performed at 345° C. for 8 hours. Then, the supply of hydrogen was stopped, and it was cooled to room temperature under nitrogen flow, and a reduced body was obtained.

[Step 3] Second stage roasting The reduced body obtained in step 2 was calcined at 350° C. for 3 hours under an air flow to obtain catalyst Ia.

(Example 1) As the oxygen-containing gas, a gas containing 14.9% by volume of oxygen and 85.1% by volume of nitrogen was prepared. As a raw material gas, a gas containing 99.5 vol % of isobutene was prepared (concentration of TBA: 0 vol %, total concentration of isobutene and TBA: 99.5 vol %). Again, prepare water vapor. Next, the oxygen-containing gas, the raw material gas, and the water vapor were mixed at the ratios of 87 parts by volume, 6 parts by volume, and 7 parts by volume, thereby obtaining a mixed gas. The composition of the mixed gas was 6% by volume of isobutene, 13% by volume of oxygen, 7% by volume of water, and 74% by volume of nitrogen.

Prepare a tubular reactor with a catalyst-packed layer. The catalyst filling layer was filled with 20 g of catalyst Ia as an oxidation catalyst.

The obtained mixed gas was supplied to the reactor at 140°C (flow rate: 87.6 NmL/min). The temperature of the catalyst filling layer is adjusted by a heat medium. Specifically, the temperature of the flow at the outlet of the catalyst packed layer of the reactor was adjusted so as to be 350°C. The temperature of the heat medium supplied to the reactor was 350°C.

The isobutene conversion and selectivity (MACR+MAA) were calculated according to the following method. (Conversion rate of isobutylene) The conversion rate (%) of isobutene was calculated according to the formula: [(moles of supplied isobutene)−(moles of unreacted isobutene)]/(moles of supplied isobutene)×100. (Selectivity (MACR+MAA)) The yield (%) of methacrolein (hereinafter referred to as MACR) is calculated according to the formula: [(moles of generated MACR)/(moles of supplied isobutene)]×100, and the selectivity of MACR is calculated according to the formula: (Production rate of MACR)/(Conversion rate of isobutene)×100 was calculated. The yield (%) of methacrylic acid (hereinafter referred to as MAA) was calculated according to the formula: [(moles of MAA produced)/(moles of isobutylene supplied)]×100, and the selectivity of MAA was calculated according to the formula: ( The yield of MAA)/(conversion rate of isobutene)×100 was calculated. The selectivity (MACR+MAA) is calculated according to the formula: (selectivity of MACR)+(selectivity of MAA).

The conversion rate of isobutene was 95.71%, and the selectivity (MACR+MAA) was 76.96%.

(Example 2) The reaction was carried out in the same manner as in Example 1, except that the supply temperature of the mixed gas to the reactor was changed to 170°C, and the isobutene conversion and selectivity (MACR+MAA) were calculated. The conversion rate of isobutene was 98.77%, and the selectivity (MACR+MAA) was 74.27%.

(Comparative Example 1) The reaction was carried out in the same manner as in Example 1, except that the supply temperature of the mixed gas to the reactor was changed to 224°C, and the isobutene conversion and selectivity (MACR+MAA) were calculated. The conversion rate of isobutene was 99.43%, and the selectivity (MACR+MAA) was 70.83%.

(Comparative Example 2) The reaction was carried out in the same manner as in Example 1, except that the supply temperature of the mixed gas to the reactor was changed to 252°C, and the isobutene conversion and selectivity (MACR+MAA) were calculated. The conversion rate of isobutene was 99.43%, and the selectivity (MACR+MAA) was 70.88%.

Table 1 summarizes the supply temperature and selectivity (MACR+MAA) of the mixed gas to the reactor.

[Table 1]

As described above, according to the method of the present invention, it was confirmed that methacrolein and/or methacrylic acid can be produced with excellent selectivity.

10: The first reactor 20: Second Reactor 50a: Gas mixer 50b: Gas mixer 52: Temperature adjustment mechanism 55: Compressor 60: Separation mechanism 80: Gas combustion mechanism 100: Production equipment for methacrolein and/or methacrylic acid F0: flow of oxygen-containing gas F1: Flow containing oxygen and combustion gases F2: Stream of raw material gas F3: Flow of combustion gas F4: Stream of water vapor F10: Flow of mixed gas F11: Streams containing methacrolein F21: Stream F22: Flow of oxygen-containing gas F23: Streams containing methacrolein F30: Contains methacrylic acid and the like F31: Streams containing methacrylic acid and heavy components F35: Contains carbon monoxide, light components and oxygen streams F38: Stream after burning L1: pipeline L2: Pipeline L3: Pipeline L4: Pipeline L10: Pipeline L21: Pipeline L22: Pipeline L23: Pipeline L30: Pipeline L31: Pipeline L35: Pipeline L38: Pipeline L101: Pipeline L102: Pipeline L103: Pipeline L104: Pipeline

Fig. 1 is a flow chart showing a method for producing methacrolein and/or methacrylic acid according to an embodiment of the present invention.

10: The first reactor

20: Second Reactor

50a: Gas mixer

50b: Gas mixer

52: Temperature adjustment mechanism

55: Compressor

60: Separation mechanism

80: Gas combustion mechanism

100: Production equipment for methacrolein and/or methacrylic acid

F0: flow of oxygen-containing gas

F1: Flow containing oxygen and combustion gases

F2: Stream of raw material gas

F3: Flow of combustion gas

F4: Stream of water vapor

F10: Flow of mixed gas

F11: Streams containing methacrolein

F21: Stream

F22: Flow of oxygen-containing gas

F23: Streams containing methacrolein

F30: Contains methacrylic acid and the like

F31: Streams containing methacrylic acid and heavy components

F35: Contains carbon monoxide, light components and oxygen streams

F38: Stream after burning

L1: pipeline

L2: Pipeline

L3: Pipeline

L4: Pipeline

L10: Pipeline

L21: Pipeline

L22: Pipeline

L23: Pipeline

L30: Pipeline

L31: Pipeline

L35: Pipeline

L38: Pipeline

L101: Pipeline

L102: Pipeline

L103: Pipeline

L104: Pipeline

Claims (3)

A method for producing methacrolein and/or methacrylic acid, comprising: mixing an oxygen-containing gas with a gas containing at least one of isobutylene and tertiary butanol to obtain a mixed gas; mixing the above-mentioned mixed gas The step of supplying to the first reactor equipped with the first oxidation catalyst at a temperature of 100~200°C; and mixing the flow discharged from the first reactor with the flow containing methacrolein and the flow of the oxygen-containing gas. The step of supplying the obtained stream to a second reactor equipped with a second oxidation catalyst, wherein the first reactor is equipped with a packing layer of the first oxidation catalyst, and the temperature of the mixed gas supplied to the first reactor is lower than The gas temperature at the outlet of the packing layer, the difference between the gas temperature at the outlet and the temperature of the mixed gas supplied to the first reactor is 120°C or more, and the first oxidation catalyst is a metal oxide containing molybdenum and bismuth. The method of claim 1, wherein the step of obtaining the mixed gas comprises: the step of diluting the oxygen-containing gas with a diluent gas, and adding the diluted oxygen-containing gas to a gas comprising at least one of isobutylene and tertiary butanol mixing steps. The method according to claim 1 or 2, wherein the first reactor is provided with a packed layer of the first oxidation catalyst and a temperature adjustment mechanism for supplying a heat medium to the first reactor to adjust the temperature of the packed layer, and the first reactor is supplied to the first reactor. The temperature of the above-mentioned mixed gas in the first reactor is lower than the temperature of the above-mentioned heat medium supplied to the above-mentioned first reactor, the temperature of the above-mentioned heat medium supplied to the above-mentioned first reactor and the above-mentioned mixture supplied to the above-mentioned first reactor The difference in temperature of the gases is 120°C or more.

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