SG181222A1

SG181222A1 - Catalyst packing apparatus and method for packing catalyst by using the same

Info

Publication number: SG181222A1
Application number: SG2011079670A
Authority: SG
Inventors: Suyasu Noriaki; Shiraishi Eiichi
Original assignee: Sumitomo Chemical Co
Priority date: 2010-11-11
Filing date: 2011-10-28
Publication date: 2012-06-28
Also published as: KR101800464B1; KR20120050902A; JP5150709B2; JP2012101189A

Abstract

OF THE DISCLOSURE5A catalyst packing apparatus 100 includes a hopper 1 for holding a solid catalyst, a first catalyst conveying path for conveying the catalyst dropping thereon from the hopper 1, a belt conveyor 3 for conveying the catalyst conveyed from the first 10 catalyst conveying path thereon, and a second catalyst conveying ,path for conveying and feeding the catalyst supplied from the belt convey or thereon to above a reaction tube 2O, and the second catalyst conveying path is an inclined chute 10 having, on an inclined face thereof , a catalyst outlet that is capable of opening/closing . figure 1

Description

SPECIFICATION

TITLE OF THE INVENTION

CATALYST PACKING APPARATUS AND METHOD FOR PACKING CATALYST

BY USING THE SAME

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a catalyst packing apparatus to be employed for packing a catalyst into each reaction tube of a fixed-bed multitubular reactor used on an industrial scale and a method for packing a catalyst by using the same.

[0002] A fixed-bed multitubular reactor used on an industrial scale includes several hundred to tens of thousands of reaction tubes, employs a system in which a solid packed substance such as a catalyst is packed into each reaction tube in a cylindrical shape to allow a reaction fluid to flow through a gap formed in the solid packed substance thus packed, and is widely employed in a petrochemical process and the like.

In order topacka catalyst ina solid form into each reaction tube of such a reactor, a catalyst packing apparatus is conventionally used.

[0003] Patent Document 1 describes a catalyst packing apparatus in which, for conveying a catalyst dropping from a hopper onto a conveyor to a plurality of reaction tubes, dividing walls are provided for partitioning a conveying face of the conveyor correspondingly to the respective reaction tubes and a thickness adjusting part is provided for setting the thickness of a layer of the conveyed catalyst soas to feed the catalyst tothe respective reaction tubes at a constant feeding rate.

[0004] Patent Document 2 discloses a catalyst packing apparatus inwhichapluralityof hoppers suppliedwithacatalystareprovided correspondingly to a plurality of reaction tubes, a line of the conveyed catalyst is formed under each hopper correspondingly to each hopper, and the catalyst dropping from each hopper is conveyed with a conveyor to be fed to each reaction tube.

[0005] Patent Document 1: Japanese Laid-Open Patent Publication

No. 11-333282

Patent Document 2: Japanese Laid-Open Patent Publication

No. 2006-142297

SUMMARY OF THE INVENTION

[0006] In the aforementioned conventional catalyst packing apparatuses, however, it 1s necessary to weigh an amount of the catalyst tobepackedintoeachreactiontubeandtostop the conveyor after packing the catalyst into the respective reaction tubes, which causes a problem that working efficiency is lowered.

Furthermore, in stopping the conveyor, the catalyst remains on the conveyor, and when the conveyor is operated again for packing the catalyst into other reaction tubes again, since the conveying speed of the conveyor is not immediately stabilized, there arises a problem that the height of the catalyst packed into a reaction tube isvariedamongthe reactiontubesduetothecatalyst remaining on the conveyor.

[0007] Accordingly, an object of the invention is to provide a catalyst packing apparatus in which the working efficiency in catalyst packing into reaction tubes of a fixed-bed multitubular reactor or the like may be improved and the height of a catalyst packed into a reaction tubemaybeuniformamong respective reaction tubes, and a method for packing a catalyst by using the same.

[0008] The present inventors have earnestly studied for overcoming the aforementioned problems, resulting in accomplishing the present invention.

[0009] Specifically, the catalyst packing apparatus and a method for packing a catalyst according to the present invention are: (1) A catalyst packing apparatus comprising: a hopper for holding a solid catalyst; a first catalyst conveying path for conveying the catalyst dropping thereon from the hopper; a belt conveyor for conveying the catalyst carried fromthe first catalyst conveying path thereon; and a second catalyst conveying path for conveying and feeding the catalyst supplied from the belt conveyor thereon to above a reaction tube, the second catalyst conveying path being an inclined chute having, on an inclined face thereof, a catalyst outlet that is capable of opening/closing. (2) The catalyst packing apparatus according to (1), wherein a downstream end of the first catalyst conveying path is movable upward/downward above/belowahorizontal positionwithanupstream end disposed upstream in conveying the catalyst used as a fulcrum.

(3) The catalyst packing apparatus according to (1) or (2), further comprising an adjusting plate for adjusting a thickness of the catalyst conveyed on the belt conveyor.

(4) The catalyst packing apparatus according to any one of (1) to (3), wherein the reaction tube has a photoelectric sensor for detecting a packing height of the catalyst disposed inside the reaction tube, and the catalyst packing apparatus further comprises a control mechanism for opening the catalyst cutlet in accordance with a detection signal output from the photoelectric sensor when the packing height of the catalyst packed into the reaction tube from above the reaction tube reaches a set value.

(5) The catalyst packing apparatus according to (4), further comprising a control mechanism for raising the downstream end of the first catalyst conveying path above the horizontal position with the upstreamend, disposedupstreamin conveying the catalyst, of the first catalyst conveying path used as the fulcrum in accordance with the detection signal.

(6) The catalyst packing apparatus according to (4) or (5), wherein the photoelectric sensor is a diffused reflection type sensor attaining a detection distance of 90 to 1000 mm with white drawing paper used as a standard detection substance.

(7) A method for packing a catalyst by using the catalyst packing apparatus of any one of (1) to (3), comprising: packing the solid catalyst held in the hopper into the reaction tube from above the reaction tube with the catalyst outlet closed; and stopping packing the catalyst into the reaction tube by opening the catalyst outlet when a packing height of the catalyst packed into the reaction tube reaches a set value. (8) A method for packing a catalyst by using the catalyst packing apparatus of any one of (4) to (6), comprising: packing the solid catalyst held in the hopper into the reaction tube from above the reaction tube with the catalyst outlet closed; and stopping packing the catalyst into the reaction tube by opening the catalyst outlet by the control mechanism for opening the catalyst outlet when the packing height of the catalyst packed into the reaction tube reaches a set value.

[0010] According to the present invention, in packing a catalyst into respective reaction tubes of a fixed-bedmultitubular reactor used on an industrial scale, the height of a catalyst packed into the respective reaction tubes may be constantly set to a prescribed height, and hence, the catalyst may be packed more easily.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1isaschematicperspectiveviewofacatalyst packing apparatus according to an embodiment of the present invention.

FIG. 2(a) is a schematic side view showing an operation of the catalyst packing apparatus performed in feeding a catalyst and FIG. 2(b) is a schematic side view showing an operation of the catalyst packing apparatus performed in stopping feeding the catalyst.

FIG. 3 is a schematic cross-sectional view showing setting of a photoelectric sensor in the present invention.

FIG. 4isaschematiccross—-sectional view showing an example of a protection tube for protecting the photoelectric sensor in the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will now be described in detail with reference to the accompanying drawings.

[0013] FIG. lisaperspectiveviewofacatalystpackingapparatus 100 according to an embodiment of the present invention. FIG. 2(a) is a schematic side view showing an operation of the catalyst packing apparatus 100 performed in feeding a catalyst, and FIG. 2(b) is a schematic side view showing an operation of the catalyst packing apparatus 100 performed in stopping feeding the catalyst.

[0014] Thecatalystpackingapparatus 100 of FIGS. 1and?2 includes a plurality of hoppers 1 independent of one another, catalyst conveyingpaths 4 (each correspondingtoa first catalyst conveying path), a belt conveyor 3, adjusting plates 5, partition walls 9, an inclined chute 10 (corresponding to a second catalyst conveying path), and reaction tube introducing hoppers 8.

[0015] (Hopper 1)

Eachhopperlholdsasolidcatalysttobepackedintoreaction tubes 20. The respective hoppers 1l of this embodiment are provided independently of one another so as to correspond to the respective reaction tubes 20. Thenumber of hoppers lincludedinonecatalyst packing apparatus is not particularly specified but is generally 1 to 50 and preferably 3 to 30.

[0016] The hopper 1 includes a rear wall 11, side walls 12 and a front wall 13. The side walls 12 and the front wall 13 are substantially vertical. The rear wall 11 and the front wall 13 are inclined so that a distance between the rear wall 11 and the front wall 13 becomes gradually smaller downward. The angle of the inclination of the rear wall 11 is suitably larger (steeper) than the repose angle of the catalyst. The rear wall 11 and the side walls 12 are formed by, for example, bending one metal plate, and the side walls 12 and the front wall 13 are integrated with each other through welding, and hence, there is no seam of welding or the like between the rear wall 11 and the side walls 12 and in addition, the inner faces of boundaries therebetween are formed in a curved shape. Therefore, the catalyst may smoothly drop from the inside of the hopper 1 by its own weight. In supplying the catalyst tothe hopper 1, the catalyst may be rubbed so as to produce a dust through powdering or fracturing of the catalyst. When the dust is supplied to a reaction tube, it may be a factor of variation in pressure loss among the reaction tubes, and therefore, the rear wall 11 may employ amesh structurewith amesh size fornot allowing the catalyst to pass therethrough but allowing the dust of the catalyst topass therethrough. Whenthemeshstructureisemployed for the rear wall 11, a collecting box (not shown) for ccllecting the dust having dropped through the mesh may be provided, or a suction device (not shown) for sucking the dust having dropped through the mesh may be provided.

It is noted that the shape of each hopper is not limited to the aforementioned shape but a hopper in, for example, a cone shape or a pyramid shape may be used.

[0017] Furthermore, a shutter 2 is provided in a lower portion ofthe frontwall 13 of thehopperl. Theopening/closingmechanism for the shutter 2 is not particularly specified, and examples are an opening/closing mechanism employing a movable plate driven to be opened/closed by compressed air or the like and an opening/closing mechanism employing a slidable plate to be slid upward/downward.

Moreover, each hopper 1 may include a vibrating mechanism for vibrating the catalyst held in the hopper.

[0018] (Catalyst conveying path 4)

The catalyst conveying path 4 is in the shape of a groove opened upward. An upstream end on the upstream side in conveying the catalyst is positioned below the hopper 1. A downstream end on the downstream side is disposed in a position in front of the hopper 1 and above the belt conveycr 3. The catalyst conveying path 4 is supported by a supporting member 15 on the hopper 1 side so as tobe rotatable with a lower portion of the supporting member

15 used as a fulcrum, and therefore, the downstream end of the catalyst conveying path 4 may be movable upward/downward above/below a horizontal position through the rotation.

The upward/downward movement of the downstream end of the catalyst conveying path 4 is caused by an elevating device 40.

The elevating device 40 includes, as shown in FIGS. 1 and 2, a hydraulic cylinder 42 having a rear end attached to the front wall 13 of the hopper 1 through a connecting member 41 and a piston rod 43 having a front end attached in the vicinity of the downstream end of the catalyst conveying path 4 through a connecting member 44.

Therefore, as shown in FIG.Z (a), when the downstream end of the catalyst conveying path 4 is moved downward below the horizontal position by the elevating device 40, the catalyst dropping from the hopper 1 may be conveyed onto the belt conveyor 3 through the catalyst conveying path 4.

Alternatively, as shown in FIG. 2(b), when the downstream end of the catalyst conveying path 4 is moved upward above the horizontal position, the catalyst dropping from the hopper 1 may be stopped to be conveyed onto the belt conveyor 3.

[0019] It is noted that the catalyst conveying path 4 may be, for example, in a cylindrical shape instead of the groove shape.

Furthermore, the elevating device 40 is not limited to the aforementioned hydraulic elevating device, but any of other known elevating devices such as an electric elevating device using a wire winder may be used as far as the downstream end of the catalyst conveying path 4 may be moved upward/downward.

[0020] (Belt conveyor 3)

Since the belt conveyor 3 may convey the catalyst conveyed from the catalyst conveying path 4 at a constant speed, it may suppress rubbing of the catalyst and may prevent the dust of the catalyst from being produced through powdering or fracturing. In addition, unevenness in the amount of the catalyst to be fed to the respective reaction tubes 20 may be avoided, and linkage of thecatalyst, i.e.,whatiscalledabridge, maybeminimally caused, so that the catalyst may be uniformly packed into the respective reaction tubes 20.

[0021] The conveying speed of the belt conveyor 3 may be appropriately controlled so that the packing rate for the catalyst may be generally 5 to 60 g/sec. and preferably 5 to 40 g/sec.

[0022] Furthermore, in a conveyance space disposed above a catalyst conveying face of the belt conveyor 3, thepartitionwalls

S are provided to arrange along the width direction of conveyance correspondingly to the respective hoppers 1. A distance between a pair of partition walls 9 corresponding to each reaction tube 20 is set to be substantially equal to the inner diameter of the reaction tube 20. Since the partition walls 9 are thus provided, formation of a bridge may be suppressed even when a large amount of the catalyst 1s projected at a time.

Alternatively, independent belt conveyors respectively driven by independent motors for respective lanes partitioned by the partition walls 9 may be used.

In conveying the catalyst, the dust of the catalyst may be adhered onto the surface of the belt conveyor 3, and hence, a brush (not shown) or a suction device (not shown) for removing the dust from the surface of the belt conveyor 3 may be provided.

[0023] (Adjusting plate 5)

Inthe conveyance space disposedabove the catalyst conveying face of the belt conveyor 3, the adjusting plate 5 corresponding to each hopper 1 is provided.

In this manner, when the height of a line of the conveyed catalyst, which has been adjusted to a feed width corresponding to each reaction tube 20 owing to the aforementioned function of the partition walls 9 in accordance with the drive of the belt conveyor 3, is beyond an appropriate height for packing into the reaction tube 20, the height of the line of the conveyed catalyst may be adjusted to the appropriate height by the adjusting plate 5. Therefore, even when a large amount of catalyst is dropped fromthe hopper 1, the line of the conveyed catalyst may be adjusted tohave an appropriate height, andthe feeding rate for the catalyst to be packed into the reaction tube 20 may be controlled by setting the conveying speed of the belt conveyor 3 to an appropriate speed.

[0024] The height adjustment by the adjusting plate 5 may be conducted by arbitrary means, and for example, a vertically long hole is formed in the adjusting plate 5 and a bolt inserted into this long hole is screwed on a supporting member (not shown), so that the adjusting plate 5 may be supported with its height adjustable.

[0025] (Inclined chute 10)

The inclined chute 10 is provided correspondingly to each line of the conveyed catalyst for guiding the catalyst from a conveyor end of the belt conveyor 3 to each reaction tube 20. A catalyst outlet 6 that may be opened/closed is formed in an inclined face of the inclined chute 10. The angle cof the inclination of the inclined chute 10 is suitably larger (steeper) than the repose angle of the catalyst.

Since the inclined chute l0ispartitionedbypartitionwalls or the like correspondingly to the respective lines of the conveyed catalyst, while keeping the lines of the conveyed catalyst having been formed during the conveyance by the belt conveyor 3, the catalyst may be packed into the reaction tubes 20. Furthermore, the catalyst outlet 6 on the inclined face of the inclined chute 101s, as shown in FIGS. 1 and 2 (a), closedby a cover 61 in conveying the catalyst, and hence the catalyst is conveyed to the reaction tube 20. On the other hand, when the cover 61 is opened, as shown in FIG. 2(b), the catalyst drops into a catalyst reservoir 7, and hence, the feed of the catalyst to the reaction tube 20 may be completely stopped without stopping the belt conveyor 3, and variation in height of the catalyst packed into the reaction tubes 20 may be further reduced. At the same time, when the downstream end of the catalyst conveying path 4 is moved upward above the horizontal position by the elevating device 40, the catalyst may be stopped to be conveyed from the hopper 1 onto the belt conveyor 3 as well as the catalyst remaining on the belt conveyor 3 and the inclined chute 10 may be discharged. In this manner, since decrease of the amount cof catalyst held in the hopper 1 may be suppressed, the frequency of supplying the catalyst to the hopper 1 may be reduced, and since the catalyst may be prevented from keeping on dropping into the catalyst reservoir 7, the frequency of collecting the catalyst from the catalyst reservoir 7 may be reduced. Furthermore, after packing the catalyst into the reactiontubesandwhenthecatalystistobepackedintonewreaction tubes, if the conditions such as the feeding rate for the catalyst are to be changed, the conditions may be changed without being influenced by the catalyst remaining on the belt conveyor 3 and the inclined chute 10, and hence, the catalyst may be smoothly packed into the new reaction tubes.

It isnotedthat thecatalyst havingdroppedontothecatalyst reservoir 7 is supplied again to the hopper 1 so as to be reused as the catalyst to be packed into the reaction tubes 20.

[0026] Moreover, the inclined chute 10 isnot limited to the shape where the inclined face is partitioned for the respective lines of the conveyed catalyst by the partition walls but may be in the shape of a groove formed with respect to each line of the conveyed catalyst or may be in the shape of a cylinder.

[0027] The cover 61 is attached, as shown in FIGS. 2 (a) and 2 (b), to the inclined face of the inclined chute 10 so as to be rotatable with an upstream end of the cover 61 disposed on the upstream side in conveying the catalyst used as a fulcrum, and a tip of a piston rodb50of ahydrauliccylinder 51 disposed below the inclined chute is fixed on a downstream end of the cover 61 disposed on the downstream side in conveying the catalyst. Therefore, when the hydraulic cylinder 51 is operated to draw the piston rod 50, the cover 61 is rotated downward to be opened (namely, the cover 61 10 is switched from a state shown in FIG.2 (a) to a state shown in

FIG. 2(b)). In closing the cover 61, the piston rod 50 is pushed out from the hydraulic cylinder 51 in the reverse manner. It is noted that a boundary between the downstream end of the cover 61 disposed on the downstream side in conveying the catalyst and the inclined chute 10 is preferably free from a level difference so as not to catch the catalyst when the cover 61 is closed.

[0028] The shape of the catalyst outlet 6 is not particularly specified, and it preferably has an area occupying most of the inclined face of the inclined chute 10 from the viewpoint of making the catalyst definitely drop onto the catalyst reservoir 7 when the catalyst ocutlet 6 1s opened.

Furthermore, when the cover 61 has a mesh structure, the dust of the catalyst or the likemay be made to droponto the catalyst reservolr 7, and hence, the variation in, for example, pressure loss of the catalyst layer packed into the respective reaction tubes 20 may be suppressed. The mesh size of the mesh structure may be appropriately determined in accordance with the shape, the size and the like of the catalyst to be used, and is set to a size not allowing the catalyst to pass therethrough but allowing the dust of the catalyst to pass therethrough. The dust or the like having passed through the mesh may be caught by the catalyst reservoir 7 or may be sucked with a suction device additionally provided. It isnoted that the inclined face of the inclined chute may employ a mesh structure in its portion other than the cover 16 61, andinthiscase, thecover6lmayormaynot haveamesh structure.

[0029] (Reaction tube introducing hopper 8B)

The reaction tube introducing hopper 8 is connected to the lower end of the inclined chute 10 and is inserted into the reaction tube 20. Thus, the catalyst having been conveyed by the inclined chutelOmaybedefinitely fedtothe reactiontube20. Thereaction tube introducing hopper 8 maybe providedwithavibratingmechanism for vibrating the catalyst to be fed to the reaction tube 20.

[0030] (Catalyst packing procedures)

Now, an example of an operation procedure of the catalyst packing apparatus will be described. (i) The downstream end of the catalyst conveying path 4 is raised above the horizontal position, the catalyst outlet © is closed, and the catalyst is supplied to the hopper 1. (ii) The belt conveyor 3 is driven and after the conveying speed is stabilized, the downstream end of the catalyst conveying path 4 is lowered below the horizontal position, and thus, the catalyst is started to be packed into the reaction tube 20. (iii) Whenthecatalysthavingbeenpackedintothereaction tube 20 reaches a prescribed packing height, the catalyst outlet 6 1s opened with the belt conveyor 3 kept on driving. Thus, the catalyst feed to the reaction tube 20 is stopped. Properly, the downstream end of the catalyst conveying path 4 is raised above the horizontal position, so as to stop the drop of the catalyst from the hopper 1. (iv) The catalyst outlet 6 is closed, and in the case where the downstreamend of the catalyst conveying path 4 has been raised above the horizontal position, it is lowered below the horizontal position, and the catalyst is properly supplied to the hopper 1, sothatthecatalystmaybestartedtobepackedintocanother reaction tube 20.

[0031] Through the aforementioned operation procedures, the catalyst is dropped from the hopper 1 onto the belt conveyor 3, and in accordance with the drive of the belt conveyor 3, a line of the conveyed catalyst is set to a feed width corresponding to the reaction tube 20 owing to the function of the partition walls 9 and is adjusted to a prescribed height by the adjusting plate 5, and the catalyst is fed to the reaction tube 20 in this state.

Therefore, without weighing the amount of catalyst to be packed and without stopping the belt conveyor 3, the feed of the catalyst to the reaction tube 20 may be stopped on a decision basis of the packing height of the catalyst having been fed to the reaction tube 20. When the feed of the catalyst is completed, the position of the catalyst packing apparatus 100 is changed by a position changing mechanism (not shown) for supplying the catalyst to other plural reaction tubes 20, and these procedures are repeated.

[0032] (Photoelectric sensor 60 and control mechanism)

The catalyst packing apparatus 100 may be provided with a photoelectric sensor 60 for detecting a packing height of the catalyst packed into the reaction tube 20. The photoelectric sensor 60 is electrically connected to a control mechanism (not shown), so as to contrel, in accordance with a detection signal output by the photoelectric sensor 60, at least the opening/closing operation of the catalyst outlet 6 of the inclined chute 10, and preferably the upward/downward movement of the downstream end of the catalyst conveying path 4 and the opening/closing operation of the catalyst outlet 6 of the inclined chute 10. Specifically, in the case where the photoelectric sensor 60 is provided in the aforementionedoperationprocedures (iii) forthecatalyst packing apparatus, when the packing height of the catalyst having been packed into the reaction tube 20 reaches a set value, the catalyst outlet 6maybeopenedbyacontrol mechanism foropeningthecatalyst outlet 6, andproperly, thedownstreamendof thecatalyst conveying path 4 may be raised above the horizontal position by a control mechanism for raising the downstream end of the catalyst conveying path 4 above the horizontal position.

[0033] When such control mechanisms are employed, the catalyst may be automatically packedwithout weighing the amount of catalyst to be packed or without artificially adjusting the packing height of the catalyst, and therefore, the labor of an operator may be reduced and the time necessary for feeding the catalyst to the reaction tubes 20 may be reduced as well as the packing height of the catalyst maybe highly precisely controlled among the plural reaction tubes 20.

[0034] The photoelectric sensor 60 is preferably inserted from above or set inside the reaction tube 20 through the reaction tube introducing hopper 8 as shown in FIG. 3. When the catalyst having been projected into the reaction tube 20 from the reaction tube introducing hopper 8 reaches a precedently set packing height H of the catalyst, the packing of the catalyst is stopped by using the aforementioned control mechanism.

[0035] The photoelectric sensor 60 is preferably what is called a diffused reflection type photoelectric sensor that emits light such as visible light or infrared ray of a light source from a detecting part (emitting part) as signal light and detects light reflected on a substance to be detected by a 1ight receiving part.

When such a photoelectric sensor 60 is employed, the detection may be carried out without touching the catalyst, and hence, neither the catalyst nor the photoelectric sensor 60 itself is damaged. Furthermore, since the detection is carried out on thebasis of reflection on the surface of the catalyst, the packing height of the catalyst may be accurately detected.

[0036] In the photoelectric sensor 60, the quantity of light (the quantity of received light) obtained in the light receiving part of the photoelectric sensor 60 resulting from the detection light projected from the photoelectric sensor 60 and reflected on the surface of a substancetobedetected (the catalyst) isdigitalized.

The thus obtained numerical value increases/decreases in accordance with the increase/decrease of the quantity of received light, and thus, a distance between the photoelectric sensor 60 and the substance to be detected may be detected. Specifically, when a distance between the photoelectric sensor 60 and the substance to be detected is large, the quantity of received light is small and hence is indicated by a small numerical value, and as the distance between the photoelectric sensor 60 and the substance tobe detected is reduced, the quantity of received light returning to the light receiving part is increased, and hence the numerical value is gradually increased. When the relationship between the numerical value of the quantity of received light and the actual distance between the photoelectric sensor 60 and the substance to be detected is precedently measured, a distance between the photoelectric sensor 60 and the substance tobedetected may be detected on the basis of a numerical value of the quantity of received light.

When a threshold value is set with respect to the numerical value of the quantity of received light of the photoelectric sensor

60, thepackingheight of the catalystmaybe adjustedin the packing of the catalyst. Specifically, before starting the packing of the catalyst, an insert position (L1) of the photoelectric sensor €0 is determined, and a threshold value is set with respect to the numerical value of the quantity of received light of the photoelectric sensor 60 on the basis of a distance between the catalyst and the photoelectric sensor 60 attained at a desired packing height H of the catalyst. Thereafter, the packing of the catalyst is started, and a packing height H of the catalyst is detected on the basis of the numerical value of the quantity of received light of the photoelectric sensor 60. When the packing height H of the catalyst reaches the set value, the packing of thecatalyst is stopped, andthus, thepackingheight of thecatalyst may be adjusted. The threshold value may be arbitrarily set in accordance with the packing height of the catalyst.

[0037] In the photoelectric sensor 60, when the guantity of received light exceeds the prescribed threshold value inaccordance with the packing height of the catalyst, a signal may be output fromthe photoelectric sensor 60. In accordancewith this signal, for example, a light may be blinked or an alarm may be sounded for informing the operator of the completion of the packing of the catalyst, so as to stop the packing of the catalyst manually, oralternatively, asignalmaybe sent fromthe photoelectric sensor 60 to a control mechanism (means), so as to stop the packing by opening the catalyst outlet 6 of the inclined chute 10 or preferably by raising the downstream end of the catalyst conveying path 4 above the horizontal position and opening the catalyst outlet 6 of the inclined chute 10.

[0038] A detection distance between the photoelectric sensor 60 andthe substance tobedetectedisadistance at which the substance to be detected is detected, namely, the quantity of received light starts to increase while the detecting part of the photoelectric sensor 60 is brought to be closer to the substance to be detected.

In the case where a standard detection substance is used as the substance to be detected, the detection distance of the photoelectricsensor 60 ispreferably 90to01000mm, more preferably 100to 500mm and furthermorepreferably100to 300mm. Forexample, whitedrawingpapermaybeusedas the standarddetection substance.

[0039] As the aforementioned diffused reflection type photoelectric sensor 60, for example, an optical fiber type photoelectric sensor (of E32 series) manufactured by Omron

Corporation or a photoelectric sensor (of PS/PZ series) manufactured by Keyence Corporation may be appropriately selected to be used. It is noted that the photoelectric sensor may include a built-in amplifier or a separated amplifier.

[0040] (Protection tube 63 for photoelectric sensor 60)

As shown in FIG. 4, thephotoelectricsensor 60maybe inserted into a protection tube 63 for use if necessary. When it is thus used, the photoelectric senscr 60 may be protected from a dust produced in packing the catalyst for retaining the detection accuracy of the photoelectric sensor 60 aswell as the photoelectric sensor 60 may be used maintenance-free over a long period of time.

The detectionaccuracyof thephotoelectric sensor 60maybe further improved by sending dry air, an inert gas, or a mixed gas thereof from, for example, a tube 62 branched from the side face of the protection tube 63 downward in the protection tube 63, namely, toward the photoelectric sensor 60.

Examples of the inert gas are nitrogen, helium and argon.

The shape of the protection tube 63 is not particularly specified and may be, for example, a cylindrical shape not having the tube 62.

The material for the protection tube 63 is not particularly specified, and it may be, for example, a stainless steel tube, a plastic tube, an aluminum tube, or a rubber tube. Furthermore, the dimension of the protection tube 63 is also not particularly specified, and its inner diameter is preferably sufficient for having a space from the photoelectric sensor for allowing dry air, an inert gas, or a mixed gas thereof to flow therein when the photoelectric sensor 60 is inserted into the protection tube 63, anditsouterdiameter ispreferablysmallerthanthe inner diameter of the reaction tube soasnot todisturb thepackingof thecatalyst.

[0041] A method for providing the protection tube 63 is not particularly specified, and for example, the photoelectric sensor 60 involved in the protection tube 63 is preferably inserted into or attached to the reaction tube 20.

[0042] Incidentally, although not particularly specified, the photoelectric sensor 60 is preferably inserted from above the reaction tube 20 without allowing it to come into contact with the reaction tube 20 so as to keep the accuracies of the detection light and the light receiving part.

[0043] (Catalyst)

The catalyst to be packed into the reaction tube 20 is not particularly specified as far as it is used for a reaction carried out by using the fixed-bed multitubular reactor. Examples of the catalyst are a catalyst used for producing unsaturated aldehyde and unsaturated carboxylic acid, a catalyst used for producing unsaturated carboxylic acid, a catalyst used for producing unsaturated nitrile, a catalyst used for hydrogenation and a catalyst used for producing chlorine. Among them, a catalyst used forproducingunsaturatedaldehyde andunsaturatedcarboxylicacid and a catalyst used for producing unsaturated carboxylic acid are preferred.

Specific examples of the catalyst used for producing unsaturatedaldehydeandunsaturatedcarboxylicacidareacatalyst used for producing acrolein and acrylic acid through gas phase catalytic oxidation of propylene with molecular oxygen, and a catalyst used for producing methacrolein and methacrylic acid through the gas phase catalytic oxidation of iscbutylene or tert-butyl alcohol with molecular oxygen.

Specific examples of the catalyst used for producing unsaturated carboxylic acid are a catalyst used for producing acrylic acid through the gas phase catalytic oxidation of propane with molecular oxygen, a catalyst used for producing acrylic acid through the gas phase catalytic oxidation of acrolein with molecular oxygen, and a catalyst used for producing methacrylic acid through the gas phase catalytic oxidation of methacrolein with molecular oxygen.

Specific examples of the catalyst used for producing unsaturatednitrileareacatalystusedforproducingacrylonitrile through gas phase catalytic ammoxidation of propylene or propane withmolecular oxygen and ammonia, anda catalyst used for producing methacrylonitrile through the gas phase catalytic ammoxidation of isobutylene or tert-butyl alcohol with molecular oxygen and ammonia.

Specific examples of the catalyst used for hydrogenation are a catalyst for removing or diluting a sulfur compound and/or a nitrogen compound included in a product by causing a reaction of a sulfur compound and/or a nitrogen compound included in a petroleum fraction with hydrogen, and/or a hydrocracking catalyst used for making heavy oil lighter.

A specific example of the catalyst used for producing chlorine is a catalyst used for producing chlorine from hydrogen chloride and oxygen.

[0044] The form of the catalyst is not particularly specified, and the catalyst may be in the form of, for example, a powder,

a grain, a circular cylinder, a sphere, a ring, or granulation obtained by grinding and classifying after molding.

The size of the catalyst is not particularly specified as far as it may be placed in the reaction tube, and the catalyst preferably has a diameter of 10 mm or less. When the diameter exceeds 10mm, it is apprehended that the activity may be lowered.

Alternatively, when the diameter of the catalyst is excessively small, pressure loss in the reaction tube is increased, and therefore, the catalyst preferably has a diameter of 0.1 mm or more in general. Furthermore, the bulk density of the catalyst is generally 0.8 to 1.5 g/ml and preferably 0.8 to 1.3 g/ml.

Moreover, the catalyst may be used together with an inert filler inactive against the catalytic reaction. Also, the catalyst may be packed into the reaction tube dividedly as a plurality of separated catalyst layers, and an inert filler layer may be sandwiched between the catalyst layers in this case.

[0045] (Reaction tube 20)

Each reaction tube 20 is of a general fixed-bedmultitubular type industrially used, and several thousand to tens of thousands of reaction tubes are used in general.

The outer diameter of each reaction tube 20 is generally approximately 10 to 60 mm, the wall thickness of the reaction tube is generally approximately 1 to 5mm, and the length of the reaction tube is generally approximately 0.3 to 10 m.

The respective reaction tubes 20 are generally metal tubes of substantially the same shape. Herein, “the substantially same shape” means that differences in the outer diameter, the wall thickness and the length among the reaction tubes are within a margin of a designerror. Incidentally, amarginof a design error ofgenerally+2.5% or less and preferably 20.5% or less is allowed.

It is noted that the inner diameter of each reaction tube and the diameter of the catalyst are preferably determined so that the inner diameter of the reaction tube may be not less than four times as large as the diameter of the catalyst, but they are not particularly specified.

[0046] It is necessary for the reaction tube to have a smooth inner face, and specifically, its surface roughness needs to be small. Thus, the catalyst packing density in each reaction tube may be increased. An example of such a reaction tube is a seamless tube free from a seam.

[0047] Each reaction tube 20 to be used may be in the shape of a coil, but a linear straight tube is generally used. The straight tube isgenerallyofavertical typetobedisposedalongthevertical direction for allowing a raw compound to pass therethrough in the vertical direction.

EXAMPLES

[0048] (Reference Example) <Preparation of catalyst>

As a catalyst, an acid salt (circular cylindrical extruded mold with a diameter of 5 mm and a height of 5 mm) of Keggin type heteropolyacid including phosphor, molybdenum, and vanadium was produced by 20 times in total in accordance with a method described in Japanese Laid-Open Patent Publication No. 2004-188231. The bulk density of the catalyst of each production lot was measured, resulting in finding that an average of the bulk densities was 1.15 g/ml, that the maximum bulk density was 1.20 g/ml, and that the minimum bulk density was 1.09 g/ml.

[0049] Incidentally, the bulk density was measured in the following manner: The catalyst was weighed by approximately 190 ml, and the resultant weight was assumed as W (g). Subscquently, after the weighed catalyst was packed inte a glass graduated cylinder with an inner diameter of 31 mm and a volume of 200 ml, the graduated cylinder was tapped 40 times on a rubber mat with a thickness of 2.5mm from a height of 20 mm, and the packed volume of the catalyst was read with accuracy of 0.5 ml, which was assumed as V (ml). The bulk density (g/ml) was obtained by dividing the thus obtained weight W (g) by the volume V (ml).

[0050] (Example 1)

A catalyst packing apparatus having the same structure as the catalyst packing apparatus 100 except that three lanes including three hoppers 1 were used and that the photoelectric sensor 60 was provided was used as the catalyst packing apparatus, and the catalyst obtained in Reference Example was packed into the reaction tubes 20. Incidentally, the catalyst obtained in

Reference Example was supplied to the hoppers 1 so that the respective hoppers 1 might respectively hold the catalyst of different lots out of the 20 lots.

Conditions for the packing were as follows:

Length of reaction tube: 2.5m

Inner diameter of reaction tube: 29.6 mmd

Photoelectric sensor 60: “E32-D32L" of diffused reflection type (manufacturedby Omron Corporation; Reflectivemodel: special beam type, detection distance in standard mode attained with white drawing paper used as the standard detection substance: 150 mm)

Amplifier unit for photoelectric sensor 60: “E3X-DA21-8” (manufactured by Omron Corporation)

Measurement mode of photoelectric sensor 60: Standard mode

Threshold value: 1500

Delay timer: 200 ms

Length (Ll) for inserting photoelectric sensor 60: 350 mm

[0051] Incidentally, the photoelectric sensor 60 used in the example has three modes, that is, fast mode, standard mode, and precise mode, and is capable of performing measurement in any of thesemodes. Atthispoint, adelaytimeelapsed from interruption of optical input to the operation or recovery of control output is designated as a response time. The response time is different among the respective modes, and is 250 ps in the fast mode, 1 ms in the standard mode, and 4 ms in the precise mode. Furthermore, when a delay timer is set, the photoelectric sensor 60 used in the example may be set so as not to operate unless the quantity of received light exceeds the threshold value for a prescribed period of time or more.

[0052] Incidentally, the photoelectric sensor 60 was inserted into the protection tube 63 (with an outer diameter of 8 mm and an inner diameter of © mm) made of stainless steel (SUS304), and dry air was allowed to blow into a space formed between the photoelectric sensor and the inner wall of the protection tube from an upper portion of the protection tube toward the detecting part provided at the tip of the photoelectric sensor at a flow rate of 50 ml/min.

Then, with the downstream end of the catalyst conveying path 4 raised above the horizontal position, the catalyst obtained in

Reference Example was supplied to the hoppers 1, and the belt conveyor 3 with a conveying speed adjusted to attain a catalyst feeding rate of 23 through 30 g/s for each lane was driven.

Thereafter, the height of the adjusting plate 5 was adjusted, the downstream end of the catalyst conveying path 4 is lowered below the horizontal position, and the catalyst was allowed to drop onto the belt conveyor 3. Thus, the catalyst packing was started by making the catalyst drop from above the reaction tubes 20 through the inclined chute 10 and the reaction tube introducing hoppers 8. The catalyst outlet 6 was opened in response to a signal output by thephotoelectric sensor 60 when the thresholdvalue was exceeded.

Andthen, adistance L2 (see FIG. 3) fromthe opening of the reaction tube tothepackedcatalystinstoppingthecatalyst feed, adistance between the photoelectric sensor and the packed catalyst (i.e.,

L2 — L1), and a time (packing time) elapsed from the start of the catalyst packing until the catalyst feed was stopped were measured respectively. Results obtained through the catalyst packing into six reaction tubes are listed in Table 1 below. It is noted that the packed amount was measured by taking the whole catalyst out of the reaction tube after completing the catalyst packing.

[0053] [Table 1]

C4 [395 | as | 6 | 1699 5 “63 | 1689 6 64 | 1690 *1: A distance from the opening of the reaction tube to the packed catalyst in stopping the catalyst feed. *2: A distance between the photoelectric sensor and the packed catalyst. *3: Packed amount/packing time

Claims

WHAT IS CLAIMED IS:

1. A catalyst packing apparatus comprising: a hopper for holding a solid catalyst; a first catalyst conveying path for conveying the catalyst dropping thereon from the hopper; a belt conveyor for conveying the catalyst conveyed from the first catalyst conveying path thereon; and a second catalyst conveying path for conveying and feeding the catalyst supplied from the belt conveyor thereon to above a reaction tube, the second catalyst conveyingpathbeingan inclined chute having, on an inclined face thereof, a catalyst cutlet that is capable of opening/closing.

2. The catalyst packing apparatus according to claim 1, wherein a downstream end of the first catalyst conveying path is movable upward/downward above/below a horizontal position with an upstream end disposed upstream in conveying the catalyst used as a fulcrum.

3. The catalyst packing apparatus according to claim 1 or 2, further comprising an adjusting plate for adjusting a thickness of the catalyst conveyed on the belt conveyor.

4. The catalyst packing apparatus according to any one of claims 1 to 3, wherein the reaction tube has a photoelectric sensor for detecting a packing height of the catalyst disposed inside the reaction tube, and the catalyst packing apparatus further comprises a control mechanism for opening the catalyst outlet in accordance with a detection signal output from the photoelectric sensor when the packing height of the catalyst packed into the reaction tube from above the reaction tube reaches a set value.

5. The catalyst packing apparatus according to claim 4, further comprising a control mechanism for raising the downstream end of the first catalyst conveying path above the horizontal position with the upstream end, disposed upstream in conveying the catalyst, of the first catalyst conveying path used as the fulcrum in accordance with the detection signal.

6. The catalyst packing apparatus according to claim 4 or Sy wherein the photoelectric sensor is a diffused reflection type sensor attaining a detection distance of 90 to 1000 mm with white drawing paper used as a standard detection substance.

7. A method for packing a catalyst by using the catalyst packing apparatus of any one of claims 1 to 3, comprising: packing the solid catalyst held in the hopper into the reaction tube from above the reaction tube with the catalyst outlet closed; and stopping packing the catalyst into the reaction tube by opening the catalyst outlet when a packing height of the catalyst packed into the reaction tube reaches a set value.

8. A method for packing a catalyst by using the catalyst packing apparatus of any one of claims 4 to 6, comprising:

packing the solid catalyst held in the hopper into the reaction tube from above the reaction tube with the catalyst outlet closed; and stopping packing the catalyst into the reaction tube by opening the catalyst outlet by the control mechanism for opening the catalyst outlet when the packing height of the catalyst packed into the reaction tube reaches a set value.