JP2006212629A - Multi-tube type fixed bed reaction device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-tube type fixed bed reaction device that is capable of preventing reaction tubes from being corroded or broken while maintaining the service life of a catalyst, and is also excellent in manufacturing efficiency and not requiring a sophisticated specification. <P>SOLUTION: The multi-tube fixed bed reaction device is at least provided with a cylindrical reactor shell, a group of reaction tubes comprising a plurality of the reaction tubes disposed in a longitudinal direction of the reaction shell, and an partially-cut circular baffle plate that controls the channel of a heating medium to be introduced into the reaction shell, wherein the group of the reaction tubes comprise a group of the reaction tubes A disposed so as to pass through all the partially-cut circular baffle plates and a group of the reaction tubes B disposed so as to pass through cut sections of the partially-cut circular baffle plates, and an internal diameter a of the reaction shell, the maximum width b of the cut section in a direction perpendicular to an edge longitudinal direction of the partially-cut circular baffle plate, and the maximum distance c from the edge that forms the cut section where the group of the reaction tubes B are disposed to the group of the reaction tubes B meet 0.05≤b/a≤0.20, and 0.02≤c/b≤0.35. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a multi-tubular fixed bed reactor that can improve the conversion rate of raw materials and maintain catalyst life and prevent corrosion or breakage of reaction tubes, and is particularly suitable for use in the production of chlorine.

  Conventionally, when manufacturing industrial gases such as chlorine gas and acrolein produced by a catalytic gas phase reaction, a multi-tubular reactor is generally used to efficiently remove heat generated by an exothermic reaction. ing. The multi-tubular reactor includes a plurality of reaction tubes filled with a catalyst in a reactor shell, and circulates a heat medium in the reactor shell to cool the reaction tube and remove reaction heat.

  In an exothermic reaction using a multi-tubular reactor, so-called hot spots may occur in places where the removal efficiency of reaction heat deteriorates due to the drift of the heat medium flow, or where the catalyst concentration is high and the reaction rate is high. . In the hot spot, the catalyst tends to deteriorate and the purity of the reaction product tends to decrease due to an excessive temperature rise.

  When the heat medium is supplied to remove heat from the reactor, the flow in the horizontal direction (lateral direction), that is, the direction perpendicular to the longitudinal direction of the reaction tube mainly affects the heat removal efficiency of the reactor. Therefore, in order to suppress the generation of hot spots, it is effective to control the lateral flow of the heat medium in the reactor shell to be uniform.

  As a method for suppressing the generation of hot spots, Patent Document 1 discloses a reaction apparatus that is a multi-tubular reaction tube provided with a heat exchange medium (heat medium) circulation device, in which baffle plates are arranged in a reactor shell. It is disclosed. Due to the presence of the baffle plate, the horizontal flow rate of the heat medium in the area bounded by the baffle plate, that is, the flow velocity in the direction perpendicular to the reaction tube is kept substantially constant. Heat transfer is constant. However, in the method described in Patent Document 1, heat removal in the longitudinal flow, that is, the flow in the direction along the reaction tube, is worse than in the transverse flow, and it cannot be said that the heat transfer in one area is sufficiently constant.

  In Patent Document 2, in a multi-tube reactor for catalytic gas phase reaction having a disk-type baffle plate, the effect of reducing heat removal due to longitudinal flow is provided by installing a space portion in which the reaction tubes are not arranged at the center of the reactor shell. Is disclosed. Patent Document 2 also discloses that the cross-sectional area of the space is 0.5 to 5% of the cross-sectional area of the reactor shell, the cross-sectional area of the disk-type baffle is 50 to 95% of the cross-sectional area of the reactor, and a perforated circle. A reactor in which the hole cross-sectional area of the plate baffle plate is 2 to 25% of the reactor cross-sectional area has been proposed. However, in the reactor of Patent Document 2, there is a possibility that a portion with poor heat removal property may remain in some reaction tubes at a portion where the flow of the heat medium is reversed at the end of the baffle plate, and a hot spot may be generated. .

  In Patent Document 3, in a gas-phase catalytic oxidation method using a fixed-bed multi-tube heat exchange reactor, a reaction in the reaction tube is prevented in order to prevent generation of hot spots due to non-uniform heat medium flow in the reactor shell. It is described that the state of the catalyst is predicted, and according to the prediction result, the catalyst filling specification in the reaction tube is changed so that the heterogeneity of the reaction state between the reaction tubes is reduced. However, in this case, there is a problem that the catalyst filling method becomes too complicated.

On the other hand, as an example of using a non-circular baffle plate, Patent Document 4 discloses that a reaction tube is provided in a heat medium passage among reaction tubes provided with a circular baffle plate in a method of obtaining chlorine by vapor phase oxidation of hydrogen chloride. A configuration that does not provide the above has been proposed. However, in the method of Patent Document 4, there is a room for improvement in terms of improving the production efficiency of chlorine because there is a loss in equipment in a portion where no reaction tube is provided.
Japanese Patent Publication No.52-15272 Japanese Patent Laid-Open No. 2001-137689 JP 2003-206244 A US Patent Application Publication No. 2004/0115118

  The present invention solves the above problems, can prevent the generation of excessive hot spots and maintain the life of the catalyst while preventing corrosion or breakage of the reaction tube due to high temperature, and requires a complicated specification. In addition, an object of the present invention is to provide a multitubular fixed bed reactor that is also excellent in production efficiency.

The present invention controls a cylindrical reactor shell, a reaction tube group composed of a plurality of reaction tubes arranged in the longitudinal direction of the reactor shell, and a flow path of a heat medium introduced into the reactor shell. A multi-tube fixed bed reactor comprising at least a baffle plate for the reaction tube, the reaction tube group being arranged so as to penetrate all of the baffle plates, The reaction tube group B is arranged so as to pass through the notch portion of the notch-shaped baffle plate, and the notch portion in the direction perpendicular to the inner diameter a of the reactor shell and the edge length direction of the notch-shaped baffle plate The maximum width b and the maximum distance c from the edge forming the missing circle where the reaction tube group B is arranged to the reaction tube group B are expressed by the following relationship:
0.05 ≦ b / a ≦ 0.20
0.02 ≦ c / b ≦ 0.35
The present invention relates to a multi-tube fixed bed reactor that satisfies

  In the multi-tubular fixed bed reactor of the present invention, the reaction tube group B is arranged in the edge length direction in a part of the region where the heat medium is controlled to flow in the surface direction of the non-circular baffle plate. The direction is preferably arranged in one or more rows. In particular, the reaction tube group B is preferably arranged in the range of 1 to 15 rows on both sides of the reactor A.

  The multitubular fixed bed reactor of the present invention is suitably used in a hydrochloric acid oxidation process in which hydrogen chloride is oxidized to obtain chlorine.

  In the multitubular fixed bed reactor of the present invention, a rectifying rod group is further provided in the same longitudinal direction as the reaction tube group so as to pass through the oval portion, and the rectifying rod group is a reaction tube group or a rectifying rod group. Are preferably arranged between the space where no is arranged and the region where the reaction tube group B is arranged.

  In the multitubular fixed bed reactor of the present invention, it is preferable that the introduction part and the discharge part of the heat medium are formed as a dividing pipe.

  In the multitubular fixed bed reactor of the present invention, the reaction tube group A and the reaction tube group B are filled with a catalyst, and the inside and inside of the reaction tube group A and the reaction tube group B are changed by changing the type and / or amount of the catalyst. Is preferably divided into a plurality of zones.

  According to the present invention, the region occupied by the missing circle portion in the missing circle baffle plate is within a certain range, and the reaction tube is arranged only in the region within the certain range at the missing circle portion, thereby The flow of the contacting heat medium is kept uniform, and heat transfer between the reaction tube and the heat medium is maintained normally. Thereby, since generation of excessive hot spots is suppressed, it is possible to prevent corrosion or breakage of the reaction tube due to high temperature while maintaining the life of the catalyst. Further, according to the present invention, it is only necessary to design the oval baffle plate and the arrangement of the reaction tubes, so that complicated specifications of the apparatus and complicated condition setting at the time of reaction are not required, and further, a part of the omission part Since the reaction tubes are arranged, an effect of excellent production efficiency can be obtained.

  The multitubular fixed bed reactor of the present invention comprises a reaction tube group consisting of a plurality of reaction tubes arranged in a longitudinal direction in a cylindrical reactor shell, and a flow path of a heat medium introduced into the reactor shell. At least a non-circular baffle for controlling. FIG. 1 is a cross-sectional view showing an example of the configuration of the multitubular fixed bed reactor of the present invention. The multitubular reaction apparatus 1 includes an upper tube plate 101, a lower tube plate 102, a heat medium introduction unit 103, a heat medium discharge unit 104, missing circular baffle plates 105 and 106, a reaction tube group A107, and a reaction tube group B108. . The heat medium is introduced into the reactor shell 109 from the heat medium introduction section 103 through a dividing pipe, typically by a pump (not shown) such as an axial flow pump or a centrifugal pump, and is directed in the direction of the arrow. It flows while changing the moving direction, and is discharged from the heat medium discharge unit 104. As shown in FIG. 1, the oval baffles 105 and 106 are alternately arranged in the longitudinal direction of the reaction tube. Since each of the missing circular baffles 105 and 106 becomes a flow path for the heat medium, the flow path of the heat medium is changed so that the moving direction of the heat medium introduced into the reactor shell is changed. It is controlled.

The distance between the baffle plates 105 and 106 is not particularly limited, and is appropriately designed to transfer heat between the heat medium and the reaction tube with a heat transfer coefficient of 1000 W / m ² K or more depending on the purpose.

  The multitubular fixed bed reactor of the present invention includes a reaction tube group A107 arranged so as to penetrate both of the oval baffles 105 and 106, and the oval baffle 105 or the oval baffles 106. And a reaction tube group B108 arranged so as to pass through the oval portion. FIG. 2 is a cross-sectional view illustrating an example of the configuration of the oval baffle plate and the reaction tube group in the multitubular fixed bed reactor of the present invention. 2 is provided with an edge 21 to provide a cut-out portion 25 as shown as a cut-out baffle plate 105 in FIG. 1, and a cut-out baffle plate 106 in FIG. As shown, having an edge 22 and providing a missing circle 26.

  Generally, in a reactor shell provided with a baffle plate, the linear velocity of the heat medium flow is reduced or turbulent flow is generated at a part where the moving direction of the heat medium is changed, so that the heat removal efficiency of the part is lowered. Tend. For example, when heat expansion is present in the reactor shell, the heat medium flow concentrates on the expansion height, and therefore the linear velocity of the heat medium flow may decrease near the upper and lower baffle plates. The heat expansion refers to an expansion joint for absorbing a difference in expansion and contraction due to thermal expansion between the reaction tube group and the reactor shell.

In the multi-tube type fixed bed reactor of the present invention, the oval baffle plate and the reaction tube have the inner diameter a of the reactor shell and the maximum width b of the oval portion in the direction perpendicular to the edge length direction of the oval baffle plate. , The maximum distance c from the edge forming the oval where the reaction tube group B is arranged to the reaction tube group B is expressed by the following relationship:
0.05 ≦ b / a ≦ 0.20
0.02 ≦ c / b ≦ 0.35
It is formed to satisfy. When the b / a is less than 0.05, the flow of the heat medium tends to be non-uniform, and when it is greater than 0.20, the region in which the heat medium flows in the surface direction of the missing circular baffle is narrow in the reactor shell. Therefore, the production efficiency of the reaction product obtained using the multitubular fixed bed reactor of the present invention cannot be obtained to a desired degree. The b / a is more preferably 0.10 or more, and more preferably 0.15 or less. On the other hand, when the above c / b is less than 0.02, the number of reaction tubes arranged in the reactor shell is small, and the production efficiency is improved by providing reaction tubes also in the missing circular baffle plate. The desired effect cannot be obtained. On the other hand, when the ratio is larger than 0.35, there is a portion where the flow of the heat medium in contact with the reaction tube group B is not uniform, and there is a risk that a hot spot is generated in the reaction tube group B. The c / b is more preferably 0.25 or less.

  The multi-tubular fixed bed reactor of the present invention has a space part that is a part where neither the reaction tube group A 107 nor the reaction tube group B 108 is arranged in a part of the omission part of the oval baffle. The boundary lines 23 and 24 shown in FIG. 2 are straight lines passing through the portion having the maximum distance c in the reaction tube group B and parallel to the length direction of the edges 21 and 22. In the present invention, the space portion is shown as a portion on the left side of the boundary line 23 in the missing circle portion 25 and a portion on the right side of the boundary line 24 in the missing circle portion 26.

  The heat removal performance is likely to deteriorate due to the disturbance of the flow of the heat medium, particularly in the region where the distance from the edge is large, among the circular portions of the circular plate baffle, but in the region within a certain range relatively close to the edge The medium flow is relatively uniform, and particularly in the vicinity of the edge, there is a region where the heat medium can be controlled to flow in the surface direction of the non-circular baffle plate. In the present invention, paying attention to the relationship between the distance from the edge and the direction and uniformity of the heat medium flow in the missing circle part, the area of the missing circle part where the heat medium flow is uniform, more preferably the heating medium A region controlled to flow in the surface direction of the non-circular baffle plate, more preferably a part of the region controlled to flow in the surface direction of the non-circular baffle plate, particularly near the edge, By arranging the reaction tube group B only, and making the other part of the missing circle part a space part where the reaction tubes are not arranged, the reaction tube is gradually heated so that excessive hot spots are generated satisfactorily. While preventing, it is possible to increase the number of reaction tubes arranged to improve the production efficiency.

  In the multi-tubular fixed bed reactor of the present invention, the generation of excessive hot spots can be suppressed by designing the size and arrangement of the oval baffle, the reaction tube group A, and the reaction tube group B. Therefore, the present invention is advantageous in that the manufacturing efficiency is excellent.

  In the multi-tubular fixed bed reactor shown in FIG. 1, the case where the heating medium flow is an upflow is shown, but the present invention is not limited to this, and either an upflow or a downflow can be adopted. good. In addition, the raw materials supplied to the reaction tube group A107 and the reaction tube group B108 may be supplied either by upflow or downflow. That is, the flow path between the raw material and the heat medium may be a parallel flow or a counter flow, and may be appropriately selected according to the purpose.

  In the multitubular fixed bed reactor of the present invention, a circulation mechanism is provided so that the heat medium discharged from the heat medium discharge unit 104 is cooled and then supplied again from the heat medium introduction unit 103 into the reactor shell. Is preferred.

  The reaction tube group B has an inner diameter a of the reactor shell, a maximum width b of a missing circle portion in a direction perpendicular to the edge length direction of the missing circle baffle plate, and a missing circle portion where the reaction tube group B is arranged. The maximum distance c from the edge to the reaction tube group B may be formed so as to satisfy the relationship shown in the above formula. For example, it may be arranged in one or more rows along the edge length direction. An example is an embodiment in which the regions are arranged at arbitrary positions in the region where arrangement is possible. FIG. 2 shows a case where the reaction tube group B is arranged in two rows on both sides of the reaction tube group A, but the number of the reaction tube group B is not limited to this.

  As a preferable arrangement mode of the reaction tube group B, an edge of the missing circular baffle plate is formed in a part of a region where the heat medium flows in the surface direction of the missing circular baffle plate. As an arrangement direction, that is, the edge length (W1) direction of 21 and 22 is arranged in one row or two or more rows along the edges 21 and 22. When the reaction tube group B is arranged with the edge length direction as the arrangement direction, a large number of reaction tubes can be efficiently arranged in a region where the distance from the edge is relatively small. When used, the production efficiency of the reaction product is improved, which is preferable. In particular, in a part of the region in which the heat medium is controlled to flow in the surface direction of the chip-shaped baffle plate, 1 to 15 rows are arranged on both sides of the reaction tube group A, that is, so as to sandwich the reaction tube group A. When the reaction tube group B is arranged within the range, it is preferable because a high production efficiency can be obtained by increasing the number of reaction tubes and generation of excessive hot spots in the reaction tube group B can be satisfactorily suppressed.

  The present invention is suitably used as a reaction apparatus used for an exothermic reaction such as an oxidation reaction. For example, a catalytic gas phase oxidation reaction in which chlorine gas is generated from hydrogen chloride gas and oxygen gas as raw materials, or propylene or isobutylene and oxygen is used. Can be employed in a catalytic gas phase oxidation reaction for producing (meth) acrolein and further (meth) acrylic acid as a raw material, but can be preferably used in a hydrochloric acid oxidation process in which hydrogen chloride is oxidized to obtain chlorine. . In addition, the multitubular fixed bed reactor of the present invention can be effectively employed for a system in which the size of the reactor is large and the heat medium flow is likely to be uneven.

  Preferable materials for the reaction tube in the multitubular reaction apparatus of the present invention include, for example, metal, glass, ceramic and the like. Examples of the metal material include carbon steel, Ni, SUS316L, SUS310, SUS304, Hastelloy S, Hastelloy C, and Inconel. Among them, Ni, particularly Ni having a carbon content of 0.02% by mass or less is preferable. The materials of the reaction tube group A and the reaction tube group B may be the same or different, but are preferably the same in that the reaction conditions and the like are easily set.

  As a preferable heat medium used in the multitubular reactor of the present invention, a heat medium generally used as a heat medium for catalytic gas phase reaction can be used, and examples thereof include a molten salt, an organic heat medium, or a molten metal. However, a molten salt is preferable from the viewpoint of thermal stability and ease of handling. Examples of the composition of the molten salt include a mixture of 50% by mass of potassium nitrate and 50% by mass of sodium nitrite, a mixture of 53% by mass of potassium nitrate, 40% by mass of sodium nitrite, and 7% by mass of sodium nitrate.

  In the multitubular fixed bed reactor of the present invention, it is preferable that the introduction part and the discharge part of the heat medium are divided pipes. As a result, the space provided in the notch portion of the notch type baffle plate is used as a flow path for the heat medium, and the reaction tubes can be efficiently laid out in parts other than the space portion, thereby obtaining good manufacturing efficiency. It is done.

  The size of the reaction tube of the multitubular fixed bed reactor of the present invention is not particularly limited, and for example, a reaction tube generally used in a gas phase catalytic reaction can be used. For example, a reaction tube having an inner diameter of 10 to 70 mm, an outer diameter of 13 to 80 mm, and a tube length of about 1000 to 10,000 mm can be preferably employed from the viewpoint of reaction efficiency and heat removal efficiency.

  The layout of the reaction tube in the multitubular reactor of the present invention is not particularly limited, but the reaction tube is arranged so that the interval between the centers of the reaction tubes is within a range of 1.1 to 1.6 times the outer diameter of the reaction tube. It is preferable to be within a range of 1.15 to 1.4 times. If the interval between the centers of each reaction tube is 1.1 times or more of the outer diameter of the reaction tube, the heat medium flow path is sufficiently secured, and the heat removal property of the reaction heat is good. If so, an increase in production cost due to an increase in the size of the reaction apparatus is prevented, and a decrease in the heat removal rate due to a decrease in the linear velocity and / or drift of the heat medium is also prevented. The size and layout interval of the reaction tubes in the reaction tube group A and the reaction tube group B may be the same or different, but are preferably the same in terms of simple setting of reaction conditions and the like.

  In the multi-tubular fixed bed reactor of the present invention, the cross-sectional area of the space portion in the reactor shell radial direction is within the range of 5 to 30% of the cross-sectional area of the reactor shell in the direction, and further 5 to 20 % Is preferable. When the cross-sectional area of the space portion is 5% or more of the cross-sectional area of the reactor shell, the heat removal of the reaction heat is good because the flow path of the heat medium is sufficiently secured, and is 30% or less. Further, an increase in production cost due to an increase in the size of the reaction apparatus is prevented, and a decrease in heat removal due to a decrease in the linear velocity and / or drift of the heat medium is also prevented.

  In the catalytic gas phase reaction to which the multitubular fixed bed reactor of the present invention is typically applied, the reaction tube is usually filled with a catalyst. In this case, the inside of the reaction tube is preferably divided into a plurality of zones by changing the type and / or amount of the catalyst. When the raw material is supplied to the reaction tube filled with the catalyst, the reaction rate is large near the reaction tube inlet, that is, in the vicinity of the raw material supply port, and as the distance from the reaction tube inlet becomes longer, the raw material concentration decreases and the reaction rate decreases. Tend to be. For this reason, in the exothermic reaction, an excessive amount of heat spots may be generated due to excessive heat generation particularly near the reaction tube inlet. When the reaction tube is divided into multiple zones with different types and / or amounts of catalyst, for example, in the vicinity of the reaction tube inlet, a runaway reaction can be achieved by filling the catalyst with low catalytic activity or reducing the amount of catalyst. As the distance from the reaction tube inlet becomes longer, the catalyst can be filled so that a catalyst having a high catalytic activity is filled or the amount of the catalyst is increased. In this case, variation in reaction rate inside the reaction tube can be reduced, generation of excessive hot spots can be suppressed, and the conversion rate of the raw material can be improved by the uniform exothermic reaction. Alternatively, the reactor shell side may be divided, and the temperature control may be performed by circulating a heat medium having a different temperature independently in each region.

  In the multi-tubular fixed bed reactor of the present invention, a rectifying rod group having the same longitudinal direction as the reaction tube group may be further provided, and the rectifying rod group includes the reaction tube group and the rectifying member in the missing circle portion. It is preferably arranged between the space where no rod group is arranged and the region where the reaction tube group B is arranged. When the rectifying rod group is provided, an effect of bringing the flow of the heat medium contacting the reaction tube group close to rectification can be obtained. The rectifying rod group can be provided, for example, within a range of 1 to 10 rows in the arrangement direction parallel to the edge length direction. When one or more rectifying rod groups are arranged, the effect of bringing the flow of the heat medium contacting the reaction tube group closer to rectification is obtained, and when arranged within 10 rows, the number of arrangement of the reaction tube groups is reduced. This prevents a decrease in production efficiency due to the increase in production cost due to an increase in the size of the reaction apparatus. More preferably, the number of rows of the rectifying rod group is in the range of 1 to 5 rows, and further 1 to 3 rows.

  FIG. 3 is a cross-sectional view for explaining an example of the configuration of the oval baffle plate, the reaction tube group, and the rectifying rod group when the rectifying rod group is provided in the multitubular fixed bed reactor of the present invention. In the configuration shown in FIG. 3, the reaction tube group A 107 is arranged so as to penetrate the oval baffle 3, and the oval portions 35 and 36 are parallel to the edge length (W 1) direction of the edges 31 and 32. Reaction tube group B108 is arranged. The rectifying rod group 110 is arranged between the space portion and the reaction tube group B108 in a portion of the missing circle portion 35 on the left side of the boundary line 33 and a portion of the missing circle portion 36 on the right side of the boundary line 34. The In FIG. 3, the space portion is shown as a portion on the left side of the boundary line 37 in the missing circle portion 35 and a portion on the right side of the boundary line 38 in the missing circle portion 36. Here, the boundary line 37 is a straight line parallel to the edge 31 passing through the point where the distance from the edge 31 is maximum in the rectifying rod group 110 arranged in the missing circle part 35, and the boundary line 38 is the missing circle part 36. In the straightening rod group 110 arranged in a straight line, the straight line is parallel to the edge 32 passing through the point where the distance to the edge 32 is maximum. 3 illustrates the case where the reaction tube group B108 and the rectifying rod group 110 are arranged one by one in the direction parallel to the edges 31 and 32, the arrangement of the reaction tube group B and the rectifying rod group is limited to this. Not.

  The shape of the rectifying rod group is preferably a shape such as a cylinder, a quadrangular prism, or a triangular prism, but the shape is not particularly limited, and the heat medium that contacts the reaction tube group as compared with the case where the rectifying rod group is not arranged. Any shape can be used as long as the flow is uniform. In the catalytic gas phase reaction, the reaction tube is usually filled with a catalyst. Therefore, as the rectifying rod group, it is preferable to arrange a dummy tube not filled with the catalyst in the reaction tube. In this case, the reaction tube group and the rectifying rod group are formed of the same material, and there is almost no difference in the heat conduction behavior between the reaction tube group and the rectifying rod group. Control of the medium supply conditions can be simplified.

  As the material of the rectifying rod group, for example, metal, glass, ceramic and the like are preferably used as in the above reaction tube group. As the metal material, carbon steel, Ni, SUS316L, SUS310, SUS304, Hastelloy S, Hastelloy C and A material such as Inconel is preferably used. For example, a combination using Ni for the reaction tube group and iron for the rectifying rod group, or a combination using Ni for the reaction tube group and Ni for the rectifying rod group may be preferably employed. The rectifying rod group may be the same material and shape as the reaction tube group, and the reaction tube group and the rectifying rod group may be formed of different materials and shapes.

  Next, the case where the multitubular fixed bed reactor of the present invention is used in a hydrochloric acid oxidation process for obtaining chlorine by oxidation of hydrogen chloride will be described below. By using the multitubular fixed bed reactor of the present invention, chlorine gas can be produced by catalytic gas phase reaction by introducing hydrogen chloride gas and oxygen gas as raw materials into a group of reaction tubes filled with a catalyst. The hydrogen chloride gas can be supplied, for example, as a hydrogen chloride-containing gas generated in a pyrolysis reaction or combustion reaction of a chlorine compound, a phosgenation reaction or chlorination reaction of an organic compound, combustion in an incinerator, or the like. At this time, the concentration of the hydrogen chloride gas in the hydrogen chloride-containing gas can be set to, for example, 10% by volume or more, further 50% by volume or more, and further 80% by volume or more from the viewpoint of production efficiency.

  The oxygen gas may be supplied alone, or may be supplied as air, for example, and may be supplied as an oxygen-containing gas. From the viewpoint of production efficiency, the concentration of oxygen in the oxygen-containing gas can be, for example, 80% by volume or more, and further 90% by volume or more. An oxygen-containing gas having an oxygen concentration of 80% by volume or more can be obtained by a normal industrial method such as an air pressure swing method or a cryogenic separation.

  As the catalyst, a catalyst containing ruthenium and / or a ruthenium compound is preferably used. In this case, the trouble of blockage of the piping or the like due to volatilization or scattering of the catalyst component is prevented, and a process for treating the volatilized or scattered catalyst component becomes unnecessary. Furthermore, since chlorine can be produced at a more advantageous temperature from the viewpoint of chemical equilibrium, subsequent processes such as a drying process, a purification process, and an absorption process can be simplified, and facility costs and operation costs can be suppressed low. In particular, it is preferable to use a catalyst containing ruthenium oxide. When a catalyst containing ruthenium oxide is used, there is an advantage that the conversion rate of hydrogen chloride is remarkably improved. The ruthenium oxide content in the catalyst is preferably in the range of 1 to 20% by mass from the viewpoint of the balance between the catalyst activity and the catalyst price. The catalyst can be used by being supported on a carrier such as silicon dioxide, graphite, rutile-type or anatase-type titanium dioxide, zirconium dioxide, and aluminum oxide.

  When multiple zones with different types and / or amounts of catalyst are provided in the reaction tube, for example, a catalyst with a low ruthenium oxide content is filled on the inlet side of the reaction tube, and a catalyst with a high ruthenium oxide content is filled on the outlet side. Such a configuration can be preferably adopted. In this case, the runaway reaction is suppressed, and the reaction rate distribution in the reaction tube is made relatively uniform, so that there is an advantage that generation of excessive hot spots is suppressed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The multi-tubular reactor of the present invention keeps the heat transfer between the reaction tube and the heat medium normal, and suppresses the generation of excessive hot spots, so that the reaction between the gas containing hydrogen chloride and the gas containing oxygen in particular. It is suitable as a multitubular reactor used for the production of chlorine.

It is sectional drawing which shows an example of a structure of the multitubular fixed bed reaction apparatus of this invention. It is sectional drawing explaining an example of a structure of the oval-shaped baffle plate and reaction tube group in the multi-tube type fixed bed reactor of this invention. It is sectional drawing explaining an example of a structure of a missing-circle baffle, a reaction tube group, and a rectification rod group in case the rectification rod group is provided in the multi-tube type fixed bed reactor of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multi-tube type fixed bed reactor, 101 Upper tube sheet, 102 Lower tube sheet, 103 Heat-medium introduction part, 104 Heat-medium discharge part, 105,106,2,3 Oval-shaped baffle plate, 107 Reaction tube group A, 108 reaction tube group B, 109 reactor shell, 110 rectifier rod group, 21, 22, 31, 32 edge, 23, 24, 33, 34, 37, 38 boundary line, 25, 26, 35, 36 notch, a inner diameter, b maximum width of the notch, c maximum distance, W1 edge length.

Claims (7)

A cylindrical reactor shell, a reaction tube group consisting of a plurality of reaction tubes arranged in the longitudinal direction of the reactor shell, and a missing circle for controlling the flow path of the heat medium introduced into the reactor shell A multi-tube fixed bed reactor comprising at least a baffle plate,
The reaction tube group includes a reaction tube group A arranged so as to pass through all the oval baffle plates, and a reaction tube group B arranged so as to pass through an oval portion of the oval baffle plate. Consists of
From the inner diameter a of the reactor shell, the maximum width b of the missing circle in the direction perpendicular to the edge length direction of the missing circle baffle, and the edge forming the missing circle where the reaction tube group B is arranged The maximum distance c to the reaction tube group B is expressed by the following relationship:
0.05 ≦ b / a ≦ 0.20
0.02 ≦ c / b ≦ 0.35
A multi-tube fixed bed reactor that meets the requirements.   The reaction tube group B includes one or more rows in a part of a region in which the heat medium is controlled to flow in the surface direction of the cut-out baffle plate with the edge length direction as an array direction. The multitubular fixed bed reactor according to claim 1, wherein   The multi-tube fixed bed reactor according to claim 2, wherein the reaction tube group B is arranged in a range of 1 to 15 rows on both sides of the reaction tube group A, respectively.   The multitubular fixed bed reactor according to claim 1, which is used in a hydrochloric acid oxidation process in which hydrogen chloride is oxidized to obtain chlorine.   A rectifying rod group is further provided in the same longitudinal direction as the reaction tube group so as to pass through the missing circle portion, and the rectifying rod group includes the space portion in which the reaction tube group or the rectifying rod group is not arranged and the The multi-tube fixed bed reactor according to claim 1, wherein the multi-tube fixed bed reactor is arranged between a region where the reaction tube group B is arranged.   The multitubular fixed bed reactor according to claim 1, wherein the introduction part and the discharge part of the heat medium are formed as a divided pipe.   The reaction tube group A and the reaction tube group B are filled with a catalyst, and the inside of the reaction tube group A and the reaction tube group B is divided into a plurality of zones by changing the type and / or amount of the catalyst. The multitubular fixed bed reactor according to claim 1.

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