JP5691151B2 - Reaction method using heat exchange reactor - Google Patents

Description

The present invention relates to a heat exchange reactor and a reaction method using the heat exchange reactor.

  As a reactor used for a gas phase reaction in which a granular solid catalyst is used, such as a gas phase catalytic oxidation reaction of propane, propylene, or acrolein, and a granular solid catalyst is used, for example, a shell and tube type reactor is used. Known (see, for example, Patent Document 1), a reaction vessel for reacting a gaseous raw material, and a plurality of heat transfer plates that are provided side by side in the reaction vessel, including a heat transfer tube, A device for supplying a heat medium to the heat transfer tube, and the reaction vessel is a vessel in which the supplied gas is discharged through a gap between adjacent heat transfer plates, and the heat transfer plate In addition, there is known a plate reactor in which a plurality of the heat transfer tubes connected at a peripheral edge or an edge of a cross-sectional shape are included and a catalyst is filled in a gap between adjacent heat transfer plates (for example, Patent Document 2). reference).

  A shell-and-tube type reactor is generally used. In particular, a plate-type reactor has a plurality of catalyst layers formed in gaps between adjacent heat transfer plates. Since it is excellent in contact with the catalyst, it is excellent from the viewpoint of efficiently producing a large amount of the product by the gas phase reaction.

  In a shell-and-tube reactor, for example, the reaction is performed by changing the particle size of the catalyst, diluting the catalyst with an inert substance, or controlling the temperature of each catalyst layer separately. In the plate reactor, the thickness of the catalyst layer can be adjusted by adjusting, for example, the distance between the plates and the size of the heat transfer pipe that is the heat medium flow path. The temperature of the reaction layer can be adjusted by adjusting the flow rate of.

  In such a reactor, in order to produce a product efficiently, that is, to obtain a larger amount of product relative to the amount of catalyst per unit volume (catalyst volume), a large amount of raw material gas flows into the reactor. It is necessary to let However, when a large amount of raw material gas is flowed into the reactor, the differential pressure in the reactor rises, and the increase in the differential pressure in the reactor promotes the combustion reaction in the oxidation reaction, reducing the product yield. There was a problem. Further, in order to allow a large amount of source gas to flow into the reactor, the energy required for compressing the source gas increases, which is economically undesirable.

JP 2003-267912 A JP 2004-202430 A

  The present invention solves the above problem, and in order to efficiently produce a product, even if a large amount of source gas is allowed to flow into the reactor, an increase in the differential pressure in the reactor can be suppressed. An object of the present invention is to provide a reaction method that does not cause a decrease in the yield of the product.

As a result of diligent research to solve the above problems, the present inventors have filled the reactor with a catalyst, and when the space velocity of air in the standard state per catalyst layer capacity is a specific value, By using a reactor in which the differential pressure between the raw material inlet and outlet of the reactor is below a certain value, it was found that the yield of the product does not decrease, and the present invention was completed.
Specifically, the pressure loss in the venting state of the reactor equipped with the catalyst layer is determined by the contact area of the catalyst and the aeration gas determined by the surface shape of the catalyst and the catalyst particle size, which are conditions related to the catalyst, and the catalyst is filled. The porosity that determines the linear velocity of the ventilation gas in the state and the passage of the ventilation gas due to cracking or pulverization caused by collision of the catalyst with the heat transfer tube wall or the surface of the heat transfer plate that forms the catalyst layer during filling The clogging rate, and further, the unevenness of the heat transfer plate that forms the catalyst layer according to the variety of shapes of the heat transfer plate, which is a feature of the plate reactor, the length of the gas flow path due to the bending of the catalyst layer, Although it is common to shell and tube reactors and plate reactors, the superficial velocity of the aerated gas and the catalyst layer depending on the average layer thickness (shell and tube reactor) and thickness (plate reactor) of the catalyst layer Ventilation gas contact due to high It is divided into factors such as time.
In order to comprehensively evaluate each of the catalyst factors affecting the pressure loss and the reactor shape factors regardless of the shell-and-tube reactor and the plate reactor, the inventors determined the reference conditions. It was found that the pressure loss and reaction performance in the reaction state can be evaluated. The present invention was completed by determining different space velocities as reference conditions using air separately for the empty state without the catalyst layer and the packed state of the catalyst layer, and determining the conditions for evaluating the performance of the reactor. .

That is, the present invention
(1) In a reactor equipped with a catalyst layer for reacting the supplied raw material gas and capable of heat removal and heating by exchanging heat with the catalyst layer, air at normal temperature is removed from the reactor outlet without the catalyst layer. The pressure difference of the reactor is 50 Pa or less when the pressure is normal pressure and the heating is not performed by a heat medium, and the space velocity is 7,200 (1 / hr) in terms of standard state per volume of the catalyst layer. And
The catalyst layer is divided into a plurality of reaction zones from the inlet of the raw material gas to the outlet, and the plurality of reaction zones are arranged so as to reduce the porosity when filling the catalyst from the inlet of the raw material gas to the outlet. It is the reaction method using the reactor which is.
(2) Preferably, the reactor includes a catalyst layer formed between adjacent heat transfer plates, and the supplied raw material gas is discharged through a gap between the adjacent heat transfer plates. The reaction method uses a reactor in which a catalyst layer is formed between the adjacent heat transfer plates.

(3) Preferably, the catalyst layer between the adjacent heat transfer plates is divided into a plurality of reaction zones from the inlet of the source gas to the outlet, and the plurality of reaction zones are directed from the inlet of the source gas to the outlet. Increasing the thickness of the catalyst layer in the length direction between adjacent heat transfer plates,
The ratio (D / d) between the particle size (D) of the catalyst filled between the adjacent heat transfer plates and the minimum space (d) between the adjacent heat transfer plates is 0.9> This is a reaction method using a plate reactor in which D / d> 0.1.

(4) Preferably, in the reaction method, the catalyst to be filled is a catalyst having a porosity in a bulk state of 60% or less.

(5) Preferably, in a state where the reactor is provided with a catalyst layer, the raw material gas has a space velocity of 1,100 (1 / hr) or more and 4,200 (1 / hr) A reaction method in which the reaction is conducted by flowing into the reactor as follows.
(6) Preferably, in the state in which the reactor is provided with the catalyst layer, the space velocity of the raw material gas is 1,800 (1 / hr) or more and 4,200 (1 / hr) A reaction method in which the reaction is conducted by flowing into the reactor as follows.

(7) Preferably, in a state in which the reactor is provided with a catalyst layer, the space velocity in terms of the standard state per volume of the catalyst layer without heating air at normal temperature with the reactor outlet pressure being normal pressure and heating with a heat medium Is a reaction method using a reactor in which the differential pressure of the reactor becomes 15 kPa or less when flowing into the reactor at 1,800 (1 / hr).

(8) Preferably, (meth) acrolein and (meth) acrylic acid are produced from propylene or isobutylene as raw materials, (meth) acrylic acid is produced from (meth) acrolein as raw materials, ethylene is oxidized to produce ethylene oxide C3 and C4 unsaturated fat produced by oxidizing at least one selected from the group consisting of C3 and C4 hydrocarbons, tertiary butanol, and C3 and C4 unsaturated aliphatic aldehydes Oxylene is oxidized by producing maleic acid from aliphatic hydrocarbons and aromatic hydrocarbons having 4 or more carbon atoms, producing one or both of group aldehydes and unsaturated fatty acids having 3 and 4 carbon atoms, This is a reaction method for producing phthalic acid, which is used for producing butadiene by oxidizing and dehydrogenating butene.

According to the present invention, even if a large amount of raw material gas is allowed to flow into the reactor in order to efficiently produce a product, the yield of the product is not reduced, and the differential pressure in the reactor is low. Therefore, by reducing the reaction pressure at the inlet of the reactor, the discharge pressure of the compressor becomes low, and it is not necessary to perform high compression. Therefore, it is possible to achieve energy saving by reducing the load of the raw material gas compressor.
In general, the power of a gas compressor is determined by the amount of gas and the gas compression ratio (compressor outlet pressure / inlet pressure). When the inlet reaction pressure or the catalyst layer differential pressure increases, the compression ratio increases. Enlarge.

The longitudinal cross-sectional view of the heat-transfer plate installed in the plate type reactor of this invention. The enlarged view of the heat-transfer plate formed by joining two corrugated sheets. The enlarged view of the III section of FIG. The enlarged view of the IV section of FIG. The enlarged view of the V section of FIG. It is a figure which shows roughly the structure of the reactor used by the present Example. It is a figure which shows roughly the structure of the reactor used by the present Example.

  The reaction method of the present invention uses a reactor equipped with a catalyst layer for reacting a supplied raw material gas and capable of heat removal and heating by exchanging heat with the catalyst layer. Such a reactor is usually a shell-and-tube reactor or a catalyst layer formed between adjacent heat transfer plates, and the supplied source gas passes through the gap between the adjacent heat transfer plates. A plate reactor that is discharged in

  As a shell and tube reactor applicable to the present invention, for example, a fixed bed type multi-tube heat exchange type reactor as described in JP-A No. 2003-267912 can be exemplified, and as a plate type reactor, , Arc, elliptical arc, corrugated plate shaped into a part of a rectangle or polygon, facing each other, and the convex portions of the corrugated plates are joined together to form a plurality of heat transfer channels Can be suitably exemplified by a reactor in which the corrugated convex surface portion and the corrugated concave surface portion of the adjacent heat transfer plates face each other to form a catalyst layer at a predetermined interval.

An example of a plate reactor applicable to the present invention will be specifically described with reference to FIGS.
In FIG. 1, the heat transfer plate 1 is formed by facing two corrugated plates, and the heat transfer plate 1 has a plurality of heat medium flow paths 2 formed inside the two corrugated plates, A space 3 sandwiched between adjacent heat transfer plates 1 can be filled with a catalyst, and a catalyst layer is formed by filling the catalyst. The reaction raw material gas is supplied from the reaction gas inlet 4, passes through the catalyst layer, and a target product is produced by the reaction, and then discharged from the reaction gas outlet 5 to the outside of the plate reactor. Although there is no restriction | limiting in the flow direction of the said reaction raw material gas, Usually, it sets to a downward flow or an upward flow.
Further, the heat medium is supplied to a plurality of heat medium flow paths 2 formed inside the heat transfer plate 1 and is caused to flow in a cross flow direction with respect to the flow direction of the reaction raw material gas. The supplied heat medium passes through the heat transfer plate 1 to cool the catalyst layer in the case of an exothermic reaction, while in the case of an endothermic reaction, the catalyst layer is heated and then discharged out of the plate reactor.

  The shape of the heat transfer plate is determined according to the shape and size of the reaction vessel, but is generally rectangular. The size of the heat transfer plate is determined according to the shape and size of the reaction vessel. For example, in the case of a rectangular heat transfer plate, the length (that is, the connection height of the heat transfer tubes) is 0.5 to 0.5. 10 m, preferably 0.5 to 5 m, and more preferably 0.5 to 3 m. From the size of a normally available thin steel plate, two plates can be joined or combined when the length is 1.5 m or more. The horizontal length (that is, the length of the heat transfer tube) is not particularly limited, and usually 0.1 to 20 m is used. Preferably it is 3-15m, Most preferably, it is 6-10m. The number of heat transfer plates is determined by the amount of catalyst used in the reaction, but is usually 10 to 300.

  Adjacent heat transfer plates in the reaction vessel may be arranged so that the convex edges of the surface of the heat transfer plate face each other, or the convex edges of the surface of one heat transfer plate are the surfaces of the other heat transfer plate. You may arrange so that a concave edge may be opposed. In FIG. 1, the convex edge of the surface of one heat-transfer plate is arranged so as to oppose the concave edge of the surface of the other heat-transfer plate. The distance between adjacent heat transfer plates is the average of the distances between the long axes of the heat transfer tubes in each heat transfer plate so that a gap of 3 to 40 mm width is formed between the heat transfer plates in the transverse direction of the heat transfer tubes. The value is preferably set in the range of 23 to 50 mm (1.1 to 5 times the sum of the half-values of the widths of the heat transfer tubes in the adjacent heat transfer plates).

  The heat transfer tube in the heat transfer plate is formed to extend in a direction orthogonal to the ventilation direction in the reaction vessel, that is, the direction of the heat medium flowing through the heat transfer tube is relative to the ventilation direction in the reaction vessel. It is preferable from the viewpoint of controlling the reaction of the raw material by adjusting the temperature of the heat medium in the heat transfer tube.

  The heat transfer tube is formed of a material having heat transfer properties in which heat is exchanged between a heat medium in the heat transfer tube and a catalyst layer circumscribing the heat transfer tube. Examples of such materials include stainless steel and carbon steel, hastelloy, titanium, aluminum, engineering plastic, and copper. Stainless steel is preferably used. Among stainless steels, 304, 304L, 316, and 316L are preferable. The cross-sectional shape of the heat transfer tube may be a circle, a substantially circular shape such as an elliptical shape or a rugby ball shape, or a polygonal shape such as a rectangle. The peripheral edge in the cross-sectional shape of the heat transfer tube means a peripheral edge in a circular shape, and the end edge in the cross-sectional shape of the heat transfer tube means an edge of a major axis end in a substantially circular shape or a single edge in a polygon.

  The cross-sectional shape and size of each of the plurality of heat transfer tubes in one heat transfer plate may be constant or different. Regarding the size of the cross-sectional shape of the heat transfer tube, for example, the width of the heat transfer tube is 5 to 50 mm, and the height of the heat transfer tube is 10 to 100 mm.

The plate reactor can be configured with an average layer thickness of a single catalyst layer, or can be divided into a plurality of reaction zones having different average layer thicknesses of catalyst layers as shown in FIG. . The average layer thickness of the catalyst layer mentioned here is an average distance between the surfaces of adjacent heat transfer plates of the catalyst layer that is perpendicular to the flow direction of the raw material gas and is sandwiched between the heat transfer plates. A heat medium can be independently supplied to the plurality of reaction zones. For example, in the case of an exothermic reaction, the heat generated by the reaction can be removed through the heat transfer plate, and the temperature in the catalyst layer can be controlled independently.

The configuration of the heat transfer plate 1 will be described in more detail with reference to FIGS.
In FIG. 2, the heat transfer plate 1 is formed by joining two corrugated plates 11. In FIG. 2, the shape of the wave is constituted by a part of an arc, but the shape is not particularly limited and can be determined in consideration of manufacturing convenience and the flow of the reaction raw material gas. Further, the height (H) of the wave and the period (L) of the wave are not particularly limited, but the height (H) is preferably 5 to 50 mm, and more preferably 10 to 30 mm. The period (L) is suitably from 10 to 100 mm, more preferably from 20 to 50 mm. These are determined from the reaction heat accompanying the reaction in the catalyst layer and the flow rate of the heat medium for removing or heating it. The distance (P) between the two heat transfer plates is such that a gap with a width of 3 to 40 mm is formed between the surfaces of the heat transfer plates in the transverse direction of the heat transfer tubes. The distance between them is 10 to 50 mm, preferably 20 to 35 mm, and is set in a range of 1.1 to 2 times the sum of the half-values of the widths of the heat transfer tubes in adjacent heat transfer plates.

3 to 5 [FIG. 3 is an enlarged view of a part III in FIG. 1, FIG. 4 is an enlarged view of a part IV in FIG. 1, and FIG. 5 is an enlarged view of a part V in FIG. The shape of the heat transfer plate 1 in the vicinity of the inlet of the raw material gas, the intermediate portion, and the vicinity of the outlet of the reactive raw material gas is shown.
In the heat transfer plate 1, two corrugated plates 11 shaped into an arc, an elliptical arc, or a rectangle face each other, and the convex surface portions a of the corrugated plates 11 are joined to each other to form a plurality of heat medium flow paths 2. Is. Then, the corrugated convex surface portion a and the corrugated concave surface portion b of the adjacent heat transfer plates 1 face each other at a predetermined interval to form a space 3.

Here, d1, d2, and d3 in the figure indicate the minimum intervals of the space 3 sandwiched between the adjacent heat transfer plates 1 in the above-described part III, part IV, and part V. d1, d2, and d3 can be changed by appropriately changing the shape of the arc, elliptical arc, or rectangle formed on the corrugated plate 11. 3 to 5, the minimum interval is set to d1 <d2 <d3. In the plate reactor of the present invention, the minimum interval (d) between the spaces between the heat transfer plates means that when there are a plurality of minimum intervals (d) in one plate reactor, there are a plurality of minimum intervals (d). The smallest interval (d) among the minimum intervals to be performed, for example, when d1, d2, and d3 are present as described above, the smallest of d1, d2, and d3, that is, in FIGS. , D1 <d2 <d3 means d1.
The above (d) is generally set to about 2 to 50 mm, preferably 5 to 20 mm.

  In FIG. 1, the interval (P) between the adjacent heat transfer plates 1 arranged is the same size as the interval P1 at the position of the reaction gas inlet 4 and the interval P2 at the position of the reaction gas outlet 5. That is, a plurality of adjacent heat transfer plates 1 are arranged in parallel to each other. Examples of the material used for the corrugated plate 11 include stainless steel, carbon steel, hastelloy, titanium, aluminum, engineering plastic, and copper. Stainless steel is preferably used. Stainless steel is preferably 304, 304L, 316, 316L. The corrugated plate 11 has a thickness of 2 mm or less, preferably 1 mm or less. Further, in the gap between adjacent heat transfer plates, providing a partition plate along the vertical direction (that is, the connection height direction of the heat transfer tubes), that is, the ventilation direction, holds the catalyst filled in each section, And from the viewpoint of functioning as a spacer for maintaining the distance between the heat transfer plates. The interval between the partitions is preferably 5 cm to 2 m, more preferably 10 cm to 1 m, and particularly preferably 20 cm to 50 cm.

  In the reaction method of the present invention, the form of the tube through which the reaction gas passes (shell-and-tube reactor) and the heat transfer plate (plate type reactor) are made into a shape that allows the gas to flow smoothly. It is characterized in that the pressure loss generated when contacting the tube and the heat transfer plate can be reduced. For example, in the reactor of the present invention, in a state where a catalyst layer is not provided in a tube (shell and tube type) or between adjacent heat transfer plates (plate type reactor), normal temperature air is used and the reactor outlet pressure is normal pressure. The pressure difference of the reactor is 50 Pa or less when the space velocity is 7,200 (1 / hr) converted into the standard state per catalyst layer volume without heating with a heating medium. By forming the shape of the tube or heat transfer plate, the pressure loss can be reduced. The differential pressure is preferably 40 Pa or less, more preferably 30 Pa or less.

In the reaction method of the present invention, the shell-and-tube reactor has a catalyst layer in the tube, and the plate reactor has a catalyst layer between adjacent heat transfer plates. The air at a reactor outlet pressure is normal pressure and is not heated by a heating medium, and is flowed into the reactor at a space velocity of 1,800 (1 / hr) in terms of standard state per volume of the catalyst layer. It is preferable to use a plate reactor in which the differential pressure of the reactor is 15 kPa or less.
What is a state in which air at normal temperature is allowed to flow into the reactor at a space velocity of 1,800 (1 / hr) in terms of the standard state per packed capacity without heating with a heat medium with the reactor outlet pressure being normal pressure? In order to increase the reaction efficiency, it is assumed that a relatively large amount of source gas is introduced into the reactor. Conventionally, in the reaction under such conditions, a large amount of raw material gas flows into the reactor to increase the reaction efficiency, thereby increasing the differential pressure of the reactor and reducing the product yield. There was a problem. By using a reactor having a differential pressure of 15 kPa or less under the above conditions, the catalyst layer has a space velocity of the raw material gas of 1,100 (1 / hr) or higher, preferably 1,800 (1 / hr) or higher. Therefore, it is preferable because a high yield can be maintained even under conditions where the amount of raw material supplied is large. Therefore, according to the present invention, the raw material gas is allowed to flow into the reactor at a space velocity of 1,100 (1 / hr) or more, preferably 1,800 (1 / hr) or more in terms of standard state per volume of the catalyst layer. It can be suitably used for conditions where the amount of raw material supplied is large relative to the catalyst layer. However, if the space velocity exceeds 4,200 (1 / hr), the differential pressure rises drastically.

The pressure difference of the reactor is also referred to as pressure loss, and its measurement method is not particularly limited. For example, a mass flow meter is used to flow a gas at a constant flow rate into the reaction tube and measure the pressure at that time. be able to. The differential pressure can be implemented by an existing pressure gauge, a differential pressure gauge, or a method in which a portion to be measured is connected by a pipe and water is added to measure the differential pressure by the difference in the height of the water column. Moreover, the said standard state means 0 degreeC and 1 atmosphere.
From the viewpoint of further improving the reaction yield, the differential pressure is preferably 12 kPa or less, and more preferably 10 kPa or less.

The following can be considered as means for achieving the differential pressure of the reactor.
(1) The length of the reactor in the raw material gas flow direction is shortened.
The differential pressure can be lowered by shortening the length of the reactor in the raw material gas flow direction and shortening the distance through which the raw material gas flows. In the case of a plate type reactor, the length in the raw material gas flow direction is usually about 0.5 to 10 m, preferably 0.5 to 5 m, more preferably 0.5 to 3 m. It is.

(2) The tube and the heat transfer plate should have a small surface roughness.
By making the tube and the heat transfer plate through which the reaction gas passes have a small surface roughness, the pressure loss generated when the reaction gas contacts the tube and the heat transfer plate can be reduced. The maximum surface roughness (Rmax) of the tube and heat transfer plate of the present invention is usually 12.5 s or less, preferably 8 s or less, more preferably 3.2 s or less.

(3) The shape of the heat transfer plate is made easy to flow gas.
By making the shape of the heat transfer plate through which the reaction gas passes into a shape that allows the gas to flow smoothly, pressure loss that occurs when the reaction gas contacts the heat transfer plate can be reduced.

(4) Change the porosity of the catalyst layer.
The catalyst layer filled between the tube and the adjacent heat transfer plate is arranged so as to reduce the porosity of the catalyst layer from the inlet of the raw material gas toward the outlet, so that the catalytic layer near the raw material gas inlet where the reaction amount is large Reaction control can be performed by reducing the gap in the catalyst layer by reducing the gap in the catalyst layer in the vicinity of the raw material gas outlet where the amount of reaction is relatively large and the amount of reaction is smaller, and the pressure loss can be relatively reduced.
The porosity of the catalyst layer refers to the ratio of the space portion that is not occupied by the catalyst when the catalyst is filled in the space. For example, the weight of the packed catalyst, the catalyst weight per grain, and the catalyst of that one grain From this volume, the volume of the filled catalyst can be calculated, and the ratio of the space not occupied by the catalyst to the volume of the catalyst layer between the heat transfer plates can be calculated. The volume of the catalyst at this time includes the internal pores.

The catalyst layer can be divided into a plurality of reaction zones from the inlet of the source gas to the outlet. For example, the reactant closest to the inlet of the source gas is set as the first reaction zone and is directed toward the outlet of the source gas. The second reaction zone and the third reaction zone. If the reaction zone is divided, the differential pressure can be reduced by increasing the porosity of the first reaction zone and decreasing the second reaction zone, the third reaction zone and the porosity. In the present invention, the porosity of the catalyst layer is preferably 50% or more in the first reaction zone, 50% or less after the second reaction zone, 50 to 65% in the first reaction zone, and the second reaction zone. After that, it is more preferable to set it as 40 to 50%.
Further, the difference in porosity between the first reaction zone and the second reaction zone is preferably 3% or more, more preferably 5% or more, and still more preferably 10% or more.

As a method of disposing the catalyst layer of the present invention so as to reduce the porosity of the catalyst layer from the inlet of the raw material gas to the outlet, a catalyst satisfying the following conditions can be used.
(A) When the catalyst layer is divided into a plurality of reaction zones, the catalyst is filled so that the particle diameter (D) of the catalyst to be filled decreases from the reaction gas inlet toward the outlet. Alternatively, the porosity can be adjusted by mixing catalysts having different particle diameters.
(B) When the catalyst layer is divided into a plurality of reaction zones, the catalyst is filled so that the bulk density of the catalyst to be filled increases from the reaction gas inlet toward the outlet.
(C) When the catalyst layer is divided into a plurality of reaction zones, the thickness of the catalyst layer is increased in the length direction between adjacent heat transfer plates of the catalyst layer to be filled from the reaction gas inlet to the outlet. . In the shell-and-tube reactor, the porosity of the catalyst layer is reduced by increasing the inner diameter of the tube continuously or stepwise from the inlet to the outlet of the reaction gas.
(D) The ratio (D / d) of the particle size (D) of the catalyst filled in the catalyst layer and the minimum space (d) between the heat transfer plates in the plate reactor of the present invention is 0. 9> D / d> 0.1.
(E) A diluent having no catalytic activity is mixed with the catalyst filled in each reaction zone to suitably adjust the porosity of the catalyst layer.

As the shape of the catalyst used in the present invention, a spherical shape having a diameter of 1 to 15 millimeters (mm), a pellet shape having a longest diameter of 2 to 15 mm, a circular outer diameter of 1 to 15 mm, and a cylinder having a height of 2 to 15 mm. A shape or a ring shape having a hole in the center of a cylinder, and having a circle outer diameter of 3 to 15 mm, a circle inner diameter of 1 to 5 mm, and a height of 2 to 10 mm can be preferably exemplified.
Further, the shape of the catalyst used in the present invention is a disc shape having a thickness of 2 to 4 mm and a diameter of 2 to 30 mm, a thickness of 2 to 4 mm, and 2 on the outer periphery of the cross section cut perpendicularly to the thickness direction. The distance between the points, the longest 2 to 30 mm long plate shape, or the rod-shaped axial length 2 to 30 mm, between the two points on the outer periphery of the cross section cut perpendicular to the rod-shaped axial direction A rod shape having a longest length (a diameter when the cross section is a circle) of 1 to 4 mm can be suitably exemplified.

The particle size (D) of the catalyst in the present invention is the diameter when the catalyst shape is the above-mentioned spherical shape, the longest diameter when the shape is a pellet, or the outer diameter of a circle when the shape is a cylinder or a ring. The longer of the heights, the longest length in the distance between two points on the outer circumference of the cross-section cut perpendicularly to the thickness direction in the case of a disk shape In the case of a rod shape, it means the length in the axial direction.
The longest diameter of the pellet shape is the distance between two surfaces when the pellet is sandwiched between two parallel surfaces, and is the maximum distance when the pellet is moved to any angle.

  The catalyst used in the present invention can preferably have a bulk density (bulk density) of 0.4 to 2.0 kg / L, more preferably 0.6 to 1.6 kg / L. The bulk density in the present invention is a value obtained by, for example, filling a 1 L volume container with a catalyst, measuring its mass, and dividing the mass by the volume.

  Further, the porosity in the bulk state of the catalyst used in the present invention can be suitably exemplified as 60% or less, more preferably 50% or less, further preferably 45% or less, and particularly preferably 40% or less. preferable. The “porosity in the bulk state” of the catalyst in the present invention refers to a container that is 10,000 times or more the volume of one catalyst, for example, 1 liter of 10,000 times that of a 0.1 cc catalyst. The catalyst is weighed in a volume container, the volume occupied by the catalyst is subtracted from 1 L, and the volume ratio of the space portion where no catalyst is present is expressed in%. The volume of the catalyst at this time includes the internal pores.

The porosity changes mainly depending on the catalyst shape and the catalyst particle size. For example, in the case of a ring-shaped catalyst having an outer diameter of 5 mm, an inner diameter of 2 mm, and a height of 3 mm, the porosity is 60% to 50%, and in the case of a disk-shaped catalyst having an outer diameter of 4 mm and a height of 3 mm or a spherical catalyst having a diameter of 5 mm Is from 50% to 35%. The exact numerical value varies depending on the presence of surface irregularities and rounded corners even in the same disk shape.
Regarding the influence of the particle size, the porosity is reduced when the particle size is small or when the particle size distribution is not true.
The measurement of the porosity is, for example, obtained by calculation from the bulk density and the specific gravity of the catalyst particles. In particular, the measurement method of the bulk density of the catalyst particles is not strictly determined, and the measurement method (constant volume method, constant weight method, The numerical value slightly varies depending on the shape of the volume measuring container such as the presence or absence of tapping, the filling height of the container, and the 1 L container.

When (a) the catalyst layer is divided into a plurality of reaction zones, the catalyst is charged so that the particle size (D) of the catalyst to be charged decreases from the reaction gas inlet toward the outlet. In the first reaction zone, (D) is preferably 5 to 15 mm, and after the second reaction zone, preferably 3 to 10 mm smaller than the first reaction zone, 7 to 12 mm in the first reaction zone, and the second reaction zone. In the following, it is more preferably 4 to 7 mm, which is smaller than the first reaction zone.
Moreover, it is preferable that the difference of the particle size (D) of a 1st reaction zone and a 2nd reaction zone shall be 1 mm or more, and it is more preferable to set it as 2 mm or more.

In addition, (b) when the catalyst layer is divided into a plurality of reaction zones, the catalyst is filled so that the bulk density of the catalyst to be filled increases from the reaction gas inlet to the outlet. Is preferably set to a bulk density of 0.6 to 1.4 kg / L in the first reaction zone and 0.8 to 1.6 kg / L larger than the first reaction zone in the second reaction zone and thereafter. More preferably, it is 0.7 to 1.2 kg / L in the first reaction zone, and is 0.8 to 1.4 kg / L which is larger than the first reaction zone in the second reaction zone and thereafter.
Further, the difference in bulk density between the first reaction zone and the second reaction zone is preferably 0.05 kg / L or more, more preferably 0.1 kg / L or more.

Further, (c) when the catalyst layer is divided into a plurality of reaction zones, the thickness of the catalyst layer is changed in the length direction between adjacent heat transfer plates of the catalyst layer to be filled from the reaction gas inlet to the outlet. In the case of increasing, the thickness of the catalyst layer is preferably 5 to 20 mm in the first reaction zone, and is preferably set to 10 to 30 mm larger than the first reaction zone after the second reaction zone. It is more preferably 7 to 10 mm, and more preferably 10 to 16 mm larger than the first reaction zone after the second reaction zone. In the present invention, the length direction between adjacent heat transfer plates refers to a direction perpendicular to the flow direction of the source gas and in which the distance between adjacent heat transfer plates is minimized, The thickness is not the maximum or minimum value of the catalyst layer thickness in the length direction between the heat transfer plates in each reaction zone, but the average of the catalyst layer thickness in the length direction between the heat transfer plates in the reaction zone. Thickness.
Moreover, it is preferable that the difference of the thickness of the catalyst layer of a 1st reaction zone and a 2nd reaction zone shall be 1 mm or more, and it is more preferable to set it as 2 mm or more.

  Further, (d) the ratio (D / d) of the particle size (D) of the catalyst filled in the catalyst layer and the minimum space (d) between the heat transfer plates in the plate reactor of the present invention Pressure loss can also be reduced by setting 0.9> D / d> 0.1. (D / d) is preferably 0.9> D / d> 0.3, and more preferably 0.7> D / d> 0.5.

  In a single plate reactor, the ratio (D / d) when there are a plurality of minimum intervals (d) (when d1, d2, and d3 are present as described above) It is the ratio of the particle size (D) of the catalyst present in the smallest interval portion to the smallest interval (d) among the plurality of minimum intervals. When the above (D / d) is 0.1 or less, the particle size (D) of the catalyst filled in the space sandwiched between the heat transfer plates becomes small, and when the reaction raw material gas is circulated, Causes pressure loss. On the other hand, when (D / d) is 0.90 or more, there is a tendency that crosslinking called a bridge is likely to occur. It doesn't progress or it takes time and effort to pull out and refill.

  The method of filling the catalyst of the present invention (hereinafter also simply referred to as a filling method) is not particularly limited as long as the catalyst can be filled as described above, and is randomly filled in the layer filled with the catalyst. However, it may be regularly arranged and filled, but it is preferable to randomly fill the catalyst for ease of catalyst filling. A specific random filling method is, for example, a method in which a catalyst is filled from above the heat transfer plate using a catalyst filling means having a conveying member in a space between adjacent heat transfer plates. A method in which the catalyst does not overlap in the vertical direction at the end portion of the conveying member can be preferably exemplified. Here, the fact that the catalyst does not overlap in the vertical direction means that the catalyst is a single layer at the terminal portion of the conveying member.

  The catalyst filling means provided with the conveying member suitably used in the present invention is not particularly limited as long as the catalyst can be adjusted so that the catalyst does not overlap in the vertical direction at the terminal portion of the conveying member.

  The reaction method of the present invention can be applied without particular limitation as long as it is a shell-and-tube reactor or a plate reactor used in a catalytic gas phase oxidation reaction. Examples of the process utilizing such a catalytic gas phase oxidation reaction include an organic compound selected from the group consisting of a process of producing ethylene oxide by oxidizing ethylene, hydrocarbons having 3 and 4 carbon atoms, and tertiary butanol. Supplying at least one kind of raw material gas, or at least one kind of organic compound raw material gas selected from the group consisting of unsaturated aliphatic aldehydes having 3 and 4 carbon atoms, and a reaction raw material gas containing molecular oxygen; Examples include a process in which a compound raw material gas is subjected to a catalytic gas phase oxidation reaction to produce one or more reactants selected from the group consisting of unsaturated aliphatic aldehydes having 3 and 4 carbon atoms and unsaturated fatty acids having 3 and 4 carbon atoms. It is done. Specifically, the reaction product is one or both of (meth) acrolein, (meth) acrylic acid, ethylene oxide, unsaturated aliphatic aldehydes having 3 and 4 carbon atoms, and unsaturated fatty acids having 3 and 4 carbon atoms, malein Examples include acid and phthalic acid.

  Among them, a process for producing (meth) acrolein and (meth) acrylic acid from propylene or isobutylene as a raw material, a process for producing (meth) acrylic acid from (meth) acrolein as a raw material, an aliphatic hydrocarbon having 4 or more carbon atoms It is preferably used in a process for producing maleic acid from a starting material or aromatic hydrocarbon, or a process for producing butadiene by oxidizing and dehydrogenating butene. In particular, the process for producing (meth) acrolein and (meth) acrylic acid generates a large amount of heat and is more preferably used in this process.

  In the reaction method of the present invention, a known catalyst can be used depending on the purpose. For example, a metal oxide containing molybdenum, tungsten, bismuth or the like, or a metal oxide containing vanadium or the like can be used.

When the source gas is propylene, preferred examples of the metal oxide include compounds represented by the following general formula (1).
Mo (a) Bi (b) Co (c) Ni (d) Fe (e) X (f) Y (g) Z (h) Q (i) Si (j) O (k) (1) )

In the above formula (1), Mo is molybdenum, Bi is bismuth, Co is cobalt, Ni is nickel, Fe is iron, X is at least one element selected from the group consisting of sodium, potassium, rubidium, cesium and thallium, Y Is at least one element selected from the group consisting of boron, phosphorus, arsenic and tungsten, Z is at least one element selected from the group consisting of magnesium, calcium, zinc, cerium and samarium, Q is a halogen element, and Si is silica , O represents oxygen.
A, b, c, d, e, f, g, h, i, j and k are the atomic ratios of Mo, Bi, Co, Ni, Fe, X, Y, Z, Q, Si and O, respectively. When the molybdenum atom (Mo) is 12, 0.5 ≦ b ≦ 7, 0 ≦ c ≦ 10, 0 ≦ d ≦ 10, 1 ≦ c + d ≦ 10, 0.05 ≦ e ≦ 3, 0.0005 ≦ f ≦ 3, 0 ≦ g ≦ 3, 0 ≦ h ≦ 1, 0 ≦ i ≦ 0.5, 0 ≦ j ≦ 40, and k is a value determined by the oxidation state of each element.

On the other hand, when the organic compound source gas is (meth) acrolein, the metal oxide is preferably exemplified by a compound represented by the following general formula (2).
Mo (12) V (a) X (b) Cu (c) Y (d) Sb (e) Z (f) Si (g) C (h) O (i) (2)
In the above formula (2), X represents at least one element selected from the group consisting of Nb and W. Y represents at least one element selected from the group consisting of Mg, Ca, Sr, Ba and Zn. Z represents at least one element selected from the group consisting of Fe, Co, Ni, Bi, and Al. However, Mo, V, Nb, Cu, W, Sb, Mg, Ca, Sr, Ba, Zn, Fe, Co, Ni, Bi, Al, Si, C, and O are element symbols. a, b, c, d, e
, F, g, h and i represent the atomic ratio of each element, and 0 <a ≦ 12, 0 ≦ b ≦ 12, 0 ≦ c ≦ 12, 0 ≦ d ≦ 8 with respect to the molybdenum atom (Mo) 12. 0 ≦ e ≦ 500, 0 ≦ f ≦ 500, 0 ≦ g ≦ 500, and 0 ≦ h ≦ 500, and i is a value determined by the oxidation state of each element except for C.

  The heat medium supplied to the shell side in the shell and tube and the heat medium supplied to the heat medium flow path of the heat transfer plate in the plate reactor are not particularly limited as long as the reaction temperature can be controlled, A high-boiling organic heat medium comprising a molten salt (nighter) or a polycyclic aromatic hydrocarbon mixture, which is a mixture of a plurality of nitrates, is preferred. Moreover, it is preferable that the temperature of a heat medium is supplied at 200-600 degreeC, More preferably, it is 200-500 degreeC. When the source gas is propylene, the temperature of the heat medium supplied to the heat medium flow path is preferably 250 to 400 ° C. On the other hand, when the source gas is acrolein, the temperature of the heat medium supplied to the heat medium flow path is preferably 200 to 350 ° C.

  The temperature difference between the inlet temperature and the outlet temperature of the heat medium is preferably 0.5 to 10 ° C, more preferably 2 to 5 ° C. In each of the heat medium flow paths, the flow rate, temperature, and flow direction of the heat medium can be changed for each of the one to a plurality of flow paths.

When the plate reactor is composed of a plurality of reaction zones having different average layer thicknesses in the length direction between adjacent heat transfer plates of the catalyst layer as shown in FIG. 1, the heat medium is divided into the plurality of reaction zones. Each is supplied at the optimum temperature. In one reaction zone, the heat medium having the same temperature may flow independently in the same direction or may flow in the counterflow direction for each of one to a plurality of flow paths. It is also possible to supply the heat medium supplied to and discharged from the heat medium flow path in a certain reaction zone to the heat medium flow path in the same or another reaction zone.
In the same reaction zone, it is preferable that the temperature of the heat medium is basically the same, but it is possible to change the temperature within a range where the hot spot phenomenon does not occur.

  The flow rate of the heat medium supplied to the heat medium flow path is determined from the amount of reaction heat and the heat transfer resistance. However, although the heat transfer resistance is usually less on the gas side of the raw material gas than the liquid heat medium, the liquid linear velocity in the heat medium flow path is preferably 0.3-2 m / m. s is adopted. In order to make the resistance on the heat medium side small and not cause a problem compared to the organic compound raw material gas side heat transfer resistance, 0.5 to 1 m / s is most suitable. If it is too large, the power of the circulation pump of the heat medium becomes large, which is not preferable in terms of economy.

  Hereinafter, examples will be shown, but the present invention is not limited to the following examples without departing from the gist thereof.

<Catalyst>
The catalysts used in the examples were prepared by the methods disclosed in JP-A-63-54942, JP-B-6-13096, JP-B-6-38918 and the like, and Mo (12) Bi (5) Co (3) Ni (2) Fe (0.4) Na (0.4) B (0.2) K (0.08) Si (24) O (x) catalyst powder (oxygen composition x Was a value determined so as to be electrically neutral as a whole compound depending on the oxidation state of each metal). This catalyst powder was molded to produce a pellet-shaped catalyst having an outer diameter of 4 mmφ and a height of 3 mm.

<Reactor>
About the reactor used in the Example, the thing of the structure of FIG. 6, 7 was used. As the heat transfer plate of the reactor, two corrugated thin stainless steel plates (thickness 1 mm) were joined to form a heat medium flow path for adjusting the reaction temperature to obtain a heat transfer plate having a heat transfer tube. A catalyst fixed bed was formed using a pair of the joined heat transfer plates.
In the reactor, the catalyst fixed bed is divided into a reaction zone 6-1, a reaction zone 6-2, and a reaction zone 6-3 from the upstream in the flow direction of the reaction gas according to the corrugated plate specifications. A pair of bonded corrugated plates were positioned in parallel, the distance between adjacent heat transfer plates was 26 mm, the plate width was 114 mm, and the plate height was 1,810 mm. Table 1 shows the period of the waveform shape (L in FIG. 7), the height of the waveform period (H in FIG. 7), and the wave number. The minimum space d between the spaces between the heat transfer plates was 8 mm.

<Example 1>
Without filling the reactor with the catalyst, the reactor outlet pressure was set to normal pressure and no heating with a heat medium, and the space velocity was 7,200 (1 / hr) at a room temperature in terms of the standard state per volume of the catalyst layer. Air, that is, 21,600 NL (liters in a standard state (0 ° C., 1 atm); the same applies hereinafter) / hr of normal temperature air flowing through the reactor, The differential pressure was 30 Pa. This pressure difference was read from the difference in the height of the water column when water was introduced into the tube connecting the reactor inlet and outlet.
On the other hand, with the above reactor filled with a pellet-shaped catalyst (diameter 4 mmφ, height 3 mm, catalyst particle size D = 5 mm, porosity 44% in the bulk state), the reactor outlet pressure was normal pressure and heat Reaction when normal temperature air with a space velocity of 1,800 (1 / hr) in terms of the standard state per catalyst layer volume was passed through the reactor without heating with a medium, that is, normal temperature air of 5,400 NL / hr. The differential pressure between the raw material gas inlet and outlet of the vessel was 7 kPa.

Each layer of the reactor was packed with catalyst. Then, a raw material gas having the following composition was introduced into the reactor at a flow rate of 6,655 (NL / hr). At this time, the reactor raw material inlet pressure was 0.09 MPaG (G represents a gauge pressure; the same applies hereinafter), and the outlet pressure was 0.047 MPaG.
PP (propylene) 8.7%
7.0% water
Oxygen 14.0%
Nitrogen 70.3%

The gas after the reaction was sampled and analyzed by gas chromatography.
The differential pressure during the reaction was 43 kPa, the PP conversion was 96.0%, and the yields of acrolein and acrylic acid were 94.5%. The results are shown in Table 2.

<Example 2>
The same catalyst as in Example 1 was filled with the same catalyst, and a raw material gas having the same composition was introduced into the reactor at a flow rate of 5,700 (NL / hr). At this time, the reactor raw material inlet pressure was 0.09 MPaG, and the outlet pressure was 0.056 MPaG.
The gas after the reaction was sampled and analyzed by gas chromatography.
The differential pressure during the reaction was 34 kPa, the PP conversion rate was 96.9%, and the yields of acrolein and acrylic acid were 94.5%. The results are shown in Table 2.

<Example 3>
In the same reactor as in Example 1, pelletized catalyst (diameter 3 mmφ, height 3 mm, catalyst particle size D = 4.2 mm, porosity 40% in bulk state) was packed in each layer, and the reactor Normal temperature air with a space velocity of 1,800 (1 / hr) in terms of standard state per volume, that is, normal temperature air of 5,400 NL / hr, was flowed to the reactor without changing the outlet pressure to normal pressure and heating with a heat medium. The differential pressure between the raw material gas inlet and the outlet of the reactor was 14 kPa.
The reactor was filled with a catalyst, and a raw material gas having the same composition as in Example 1 was flowed into the reactor at a flow rate of 6,655 (NL / hr). At this time, the reactor raw material inlet pressure was 0.13 MPaG, and the outlet pressure was 0.067 MPaG.
The gas after the reaction was sampled and analyzed by gas chromatography.
The differential pressure during the reaction was 65 kPa, the PP conversion was 97.7%, and the yields of acrolein and acrylic acid were 92.3%. The results are shown in Table 2.

<Comparative Example 1>
The reactor of the comparative example was a single tube reactor, and a reactor in which a single tube filled with a catalyst was bathed in a heat medium was used. As the reaction tube of the reactor, a cylindrical reaction tube having an inner diameter of 25 mm and a length of 3,200 mm was used, and the length of the catalyst layer was 2,800 mm. Without filling the reactor with the catalyst, the reactor outlet pressure was set to normal pressure and no heating with a heat medium, and the space velocity was 7,200 (1 / hr) at a room temperature in terms of the standard state per volume of the catalyst layer. The differential pressure between the raw material gas inlet and outlet of the reactor was 80 Pa when air, that is, air at room temperature of 9,896 NL / hr, was passed through the reactor.
On the other hand, in the state where the above-mentioned reactor is filled with the same catalyst as in Example 1, the space velocity is 1,800 in terms of the standard state per volume of the catalyst layer with the reactor outlet pressure being normal pressure and without heating with a heat medium. When a normal temperature air of (1 / hr), that is, a normal temperature air of 2,474 NL / hr was passed through the reactor, the differential pressure between the raw material gas inlet and the outlet of the reactor was 15 kPa.

The reactor was filled with a catalyst, and a raw material gas having the following composition was introduced into the reactor at a flow rate of 3,132 (NL / hr). At this time, the reactor raw material inlet pressure was 0.12 MPaG, and the outlet pressure was 0.062 MPaG.
PP (propylene) 8.7%
7.0% water
Oxygen 14.0%
Nitrogen 70.3%

The gas after the reaction was sampled and analyzed by gas chromatography.
The differential pressure during the reaction was 58 kPa, the PP conversion was 91.7%, and the yields of acrolein and acrylic acid were 86.5%. The results are shown in Table 2.
Although an attempt was made to further increase the temperature and increase the PP conversion rate, the operation was stopped because the temperature of the catalyst layer increased rapidly.

  Shell-and-tube reactors and plate reactors are generally superior in terms of efficiently producing a large amount of gas phase reaction products, and the products of the present invention can be produced with high efficiency and high yield. can do. Further expansion of versatility of shell-and-tube reactors and plate reactors is expected.

DESCRIPTION OF SYMBOLS 1 Heat transfer plate 2 Heat-medium flow path 3 Space 4 Reaction gas inlet 5 Reaction gas outlet 6-1 1st reaction zone 6-2 2nd reaction zone 6-3 3rd reaction zone 11 Corrugated sheet a Convex surface part b of corrugated sheet Corrugated concave portion P, P1, P2 Distance between plates L Wave period H Wave heights d1, d2, d3 Minimum spacing between two adjacent heat transfer plates

Claims (4)

In a reactor for producing (meth) acrolein and (meth) acrylic acid using propylene or isobutylene as a raw material, which has a catalyst layer for reacting the supplied raw material gas and can exchange heat with the catalyst layer to remove heat and heat ,
The reactor includes a catalyst layer formed between adjacent heat transfer plates, and the supplied source gas is discharged through a gap between the adjacent heat transfer plates;
The heat transfer plate is formed by facing two corrugated plates shaped into an arc, an elliptical arc or a rectangle, and joining the convex portions of the corrugated plates to form a plurality of heat medium flow paths,
The temperature of the heat medium supplied to the heat medium flow path is 250 to 400 ° C,
The length of the reactor in the raw material gas flow direction is 0.5-3 m,
In the state where the catalyst layer is not provided, the above-mentioned reaction is performed with normal-temperature air at a reactor outlet pressure of normal pressure and without heating with a heat medium, and a space velocity of 7,200 (1 / hr) in terms of standard state per catalyst layer volume The differential pressure of the reactor when flowing into the reactor is 40 Pa or less,
The catalyst layer is divided into a plurality of reaction zones from the inlet of the raw material gas to the outlet, and the plurality of reaction zones are arranged so as to reduce the porosity when filling the catalyst from the inlet of the raw material gas to the outlet. , porosity of the catalyst layer, the first reaction zone at least 50%, in the second reaction zone after not more than 50% state, and are the difference between the porosity of the first reaction zone and the second reaction zone is 10% or more ,
The plurality of reaction zones increase the thickness of the catalyst layer in the length direction between adjacent heat transfer plates from the inlet to the outlet of the raw material gas,
The ratio (D / d) between the particle size (D) of the catalyst filled between the adjacent heat transfer plates and the minimum space (d) between the adjacent heat transfer plates is 0.9> using D / d> 0.3 der Ru reactor,
In the state in which the reactor is provided with the catalyst layer, the reaction is performed with the raw material gas at a space velocity of 1,100 (1 / hr) or more and 4,200 (1 / hr) or less in terms of standard state per volume of the catalyst layer. A reaction method in which a reaction is conducted by flowing into a vessel . The reaction method according to claim 1 , wherein the catalyst forming the catalyst layer is a catalyst having a porosity in a bulk state of 60% or less. In the state in which the reactor is provided with the catalyst layer, the reaction is performed with the raw material gas at a space velocity of 1,800 (1 / hr) or more and 4,200 (1 / hr) or less in terms of standard state per volume of the catalyst layer. The reaction method according to claim 1 or 2 , wherein the reaction is conducted by flowing into a vessel. In the state in which the reactor is equipped with the catalyst layer, the space velocity is 1,800 (1 in terms of standard state per volume of the catalyst layer without heating with normal temperature air at the reactor outlet pressure and normal pressure. The reaction method according to any one of claims 1 to 3 , wherein a reactor is used in which the differential pressure of the reactor when flowing into the reactor as / hr) is 15 kPa or less.

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