LU501564A1

LU501564A1 - Scr low-temperature denitration device

Info

Publication number: LU501564A1
Application number: LU501564A
Authority: LU
Inventors: Lan Fan; Rui Zhang; Jiabing Wan; Sulin Wang
Original assignee: Yancheng City Lan Feng Env Engineering Co Ltd
Priority date: 2022-03-01
Filing date: 2022-03-01
Publication date: 2022-09-01
Also published as: LU501564B1

Abstract

The present disclosure provides a selective catalytic reduction (SCR) low-temperature denitration device, including a reactor shell which has a flue gas inlet and a flue gas outlet; an ammonia spraying grille for mounting a spraying head; a flue gas overflow channel is reserved between a catalyst storage tank and an inner side wall of the reactor shell; the flue gas overflow channel is communicated to the flue gas outlet; the catalyst storage tank includes an outer catalyst tank and an inner catalyst tank located in the outer catalyst tank; a material turning member is mounted in the inner catalyst tank; the material turning member has a fork sheet capable of rotating in a reciprocating manner; the fork sheet toggles catalyst particles in the inner catalyst tank; a reactor inner pipe is in the middle of the outer catalyst tank; the inner catalyst tank is clung to the reactor inner pipe.

Description

DESCRIPTION HUS01564 SCR LOW-TEMPERATURE DENITRATION DEVICE

TECHNICAL FIELD

[0001] The present disclosure belongs to the technical field of environmental protection equipment, and specifically relates to a selective catalytic reduction (SCR) low-temperature denitration device.

BACKGROUND

[0002] Pollutants in flue gas of a lime kiln mainly include dust, sulfur dioxide, nitrogen oxides, etc. According to a flue gas treatment path, the pollutants are desulfurized at first, then enter a high-temperature cloth bag for dust removal, enter an SCR reactor for denitration, and are finally discharged by an induced draft fan into a chimney.

[0003] Since the flue gas after desulfurization still contains a small amount of SOX, the flue gas reacts with the ammonia gas in the SCR reactor to generate ammonium salt, and the ammonium salt is adsorbed in a catalyst of the reactor, so that the catalyst is easily agglomerated or deactivated due to the increase in viscosity, and the operating cycle of the catalyst is shortened. In addition, since a catalyst bed is usually a fixed bed, on the premise of using a certain number of catalysts, a contact area between the flue gas and the catalyst is small, and the reaction time between the flue gas and the catalyst is short, resulting in insufficient adsorption and cooling effect of the catalyst on the flue gas. The catalytic reaction efficiency is low, which affects the discharging index of the flue gas.

SUMMARY

[0004] The present disclosure aims to provide an SCR low-temperature denitration device, so as to solve the problems that a catalyst in a denitration reactor is easily agglomerated or deactivated, the adsorption and cooling effect of the catalyst on flue gas is insufficient, and the catalysis efficiency is low.

[0005] The present disclosure provides the following technical solution: HUS01564

[0006] An SCR low-temperature denitration device includes:

[0007] a reactor shell which has a flue gas inlet and a flue gas outlet;

[0008] an ammonia spraying grille on which a spraying head communicated to an ammonia spraying pipeline is mounted,

[0009] a catalyst storage tank which is fixed in the reactor shell and is located below the ammonia spraying grille, a flue gas overflow channel being reserved between a catalyst storage tank and an inner side wall of the reactor shell; the flue gas overflow channel being communicated to the flue gas outlet; the catalyst storage tank comprising an outer catalyst tank and an inner catalyst tank located in the outer catalyst tank; a material turning member being mounted in the inner catalyst tank; the material turning member having a fork sheet capable of rotating in a reciprocating manner; when rotating, the fork sheet toggling catalyst particles in the inner catalyst tank;

[0010] a reactor inner pipe which is located in the middle of the outer catalyst tank and extends in a longitudinal direction, the inner catalyst tank being clung to the reactor inner pipe; a top of the reactor inner pipe being provided with a gas inlet communicated to the flue gas inlet; a bottom of the reactor inner pipe being of a sealed structure; flue gas entering the reactor inner pipe from the gas inlet passing through the inner catalyst tank and the outer catalyst tank in a radial direction and entering the flue gas overflow channel.

[0011] Preferably, the material turning member further includes a main guide cylinder, an auxiliary guide cylinder, a driving shaft, a driven shaft, and a driving device; two sliding arms of the fork sheet respectively slidably penetrate through the main guide cylinder and the auxiliary guide cylinder; the driving shaft and the driven shaft are fixedly connected to the main guide cylinder and the auxiliary guide cylinder, respectively; the driving shaft and the driven shaft are both mounted on the reactor shell; and the driving device is in driving connection to the driving shaft; and the driving device is mounted outside the reactor shell.

[0012] Preferably, the fork sheet further includes two tail arms; the two tail arms and the two sliding arms are connected with each other to form a fork structural body; the main guide cylinder and the auxiliary guide cylinder are both provided with guide holes HUS01564 adapted to the sliding arms; and the sliding arms are slidable along the guide holes.

[0013] Preferably, an included angle between the two sliding arms is 90 degrees.

[0014] Preferably, a length of the sliding arm is greater than that of the tail arm.

[0015] Preferably, the driving device includes a motor, a driving wheel, a driven wheel, a transmission wheel, and a belt; the motor is in driving connection to the driving wheel; the driving wheel is engaged with the driven wheel; a pitch diameter of the driving wheel is less than a pitch diameter of the driven wheel; the driven wheel is in key connection to one driving shaft; the transmission wheel is in key connection to other driving shafts; and the belt is tensioned to the driven wheel and the transmission wheel in an engaged manner.

[0016] Further, a mounting baffle plate is fixed at the top of the catalyst storage tank; the baffle plate prevents flue gas from entering the catalyst storage tank from the top of the catalyst storage tank; and the baffle plate is fixed on the inner wall of the reactor shell.

[0017] Preferably, side walls of the outer catalyst tank and the inner catalyst tank are provided with hollow net structures; a mesh of the hollow net structure is less than a particle size of the catalyst particle; the outer catalyst tank is closely filled with the catalyst particles; and the inner catalyst tank is loosely filled with the catalyst particles.

[0018] Further, an agent feeding pipe and an agent discharging pipe are respectively mounted at the top and bottom of the catalyst storage tank; and the other end of the agent feeding pipe and the other end of the agent discharging pipe respectively penetrate through the top and bottom of the reactor shell.

[0019] Further, the bottom of the catalyst storage tank is supported on the reactor shell by a base; the base comprises at least two supporting plates arranged at an interval; and a plurality of ventilation holes are formed in the supporting plates.

[0020] The present disclosure has the beneficial effects:

[0021] In the present disclosure, the catalyst storage tank is mounted in the reactor shell, and the flue gas overflow channel is reserved between the catalyst storage tank and the inner side wall of the reactor shell. The reactor inner pipe is located in the middle of the catalyst storage tank and extends in the longitudinal direction. After HUS01564 reacting with the ammonia gas sprayed by the ammonia spraying grille, the flue gas enters the reactor inner pipe, then passes through the catalyst storage tank in the radial direction for catalytic reaction, enter the flue gas overflow channel, and leaves out of the reactor shell from the flue gas outlet, so as to achieve efficient denitration and dust removal effects.

[0022] In the present disclosure, the outer catalyst tank and the inner catalyst tank are arranged in the catalyst storage tank to achieve segmented catalysis. The material turning member is mounted in the inner catalyst tank. The material turning member has the fork sheet capable of rotating in the reciprocating manner. During rotation, the fork sheet toggles the catalyst particles in the inner catalyst tank to avoid dust in the flue, the remaining SOX, and the ammonium salt generated by the reaction with the ammonia gas from being adhered to the catalyst particles on the innermost layer to cause the catalyst on the innermost layer to be quickly agglomerated and deactivated and cause gas flow blockage. At the same time, the flue gas is in full contact with the catalyst to improve the catalysis efficiency. Furthermore, the flow direction of the flue gas in the inner catalyst tank is disturbed to prolong the reaction time between the flue gas and the catalyst, which is conductive to cooling the flue gas.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of this specification to explain the present disclosure together with the embodiments of the present disclosure, and do not constitute restrictions to the present disclosure. In the drawings:

[0024] FIG. 1 is a schematic diagram of an internal structure of the present disclosure;

[0025] FIG. 2 is a schematic structural diagram of an initial state of a material turning member of the present disclosure;

[0026] FIG. 3 is a schematic structural diagram of a turning state of a material turning member of the present disclosure;

[0027] FIG. 4 is a side view of a mounting structure of a material turning member of the present disclosure; and 501564

[0028] FIG. 5 is a schematic diagram of a pitching structure of a diversion member distributed in a reactor shell of the present disclosure.

[0029] Reference signs in the drawings: 1: reactor shell; 2: ammonia spraying grille; 3: catalyst storage tank; 4: material turning member; 5: reactor inner pipe; 6: flue gas inlet; 7: flue gas outlet; 8: spraying head; 9: baffle plate; 10: flue gas overflow channel; 11: outer catalyst tank; 12: inner catalyst tank; 13: agent feeding pipe; 14: agent discharging pipe; 15: fork sheet; 16: main guide cylinder; 17: auxiliary guide cylinder; 18: driving shaft; 19: driven shaft; 20: sliding arm; 21: tail arm; 22: guide hole; 23: motor; 24: driving wheel; 25: driven wheel; 26: transmission wheel; 27: belt; 28: supporting plate; 29: ventilation hole; 30: gas inlet; 31: pressure relief hole; 32: diversion plate; 33: ventilation hole.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Embodiment 1

[0031] As shown in FIG. 1 to FIG. 4, an SCR low-temperature denitration device includes a reactor shell 1, an ammonia spraying grille 2, a catalyst storage tank 3, a material turning member 4, and a reactor inner pipe 5. A top of the reactor shell 1 has a flue gas inlet 6, and a bottom is provided with a flue gas outlet 7. Low-temperature flue gas (170-2507C) after desulfurization is injected into the reactor shell 1 for denitration from the flue gas inlet 6.

[0032] A spraying head 8 communicated to an ammonia spraying pipeline is mounted on the ammonia spraying grille 2. The spraying head 8 sprays gasified ammonia gas to denitrate NOX-containing flue gas. Main products after the reaction include N2 and H20. After pollutants such as ammonium salt and dust are removed by the catalyst storage tank, the flue gas is discharged out of the reactor shell 1 from the flue gas outlet

7.

[0033] The catalyst storage tank 3 is fixed in the reactor shell 1 and is located below the ammonia spraying grille 2. A baffle plate 9 is fixedly mounted at the top of the catalyst storage tank 3. The baffle plate 9 prevents the flue gas from directly entering the catalyst storage tank 3 from the top of the catalyst storage tank 3. The baffle plate 9 HUS01564 is welded or screwed to an inner wall of the reactor shell 1. A flue gas overflow channel is reserved between the catalyst storage tank 3 and the inner side wall of the reactor shell 1, and the flue gas overflow channel 10 is communicated to the flue gas outlet 7. The catalyst storage tank 3 includes an outer catalyst tank 11 and an inner catalyst tank 12 located in the outer catalyst tank 11. The inner catalyst tank 12 is loosely filled with catalyst particles. The outer catalyst tank 11 is closely filled with catalyst particles. The flue gas firstly contacts with the catalyst in the inner catalyst tank 12 for SCR reaction, which pre-desalts the pollutants in the flue gas, and the clean flue gas enters the outer catalyst tank 11 for continuous adsorption and decontamination. Side walls of the outer catalyst tank 11 and the inner catalyst tank 12 are both provided with hollow net structures. A mesh of the hollow net structure is less than a particle size of the catalyst particle. The flue gas can enter the catalyst storage tank from the meshes.

[0034] An agent feeding pipe 13 and an agent discharging pipe 14 are respectively mounted at the top and bottom of the inner catalyst tank 12. The other end of the agent feeding pipe 13 and the other end of the agent discharging pipe 14 respectively penetrate through the top and bottom of the reactor shell 1. The catalyst particles in the inner catalyst tank 12 need to be replaced or regenerated more frequently. When the catalyst is replaced, a valve of the agent discharging pipe 14 is opened to discharge the catalyst particles out of the reactor shell 1, and fresh catalyst particles are conveyed into the inner catalyst tank 12 from the agent feeding pipe 13. In the same way, the outer catalyst tank 11 is also communicated to a corresponding pipeline to feed and discharge catalyst particles.

[0035] The reactor inner pipe 5 is located in the middle of the outer catalyst tank 11 and extends in its longitudinal direction. The reactor inner pipe 5, the catalyst storage tank 3, and the reactor shell 1 are all disposed coaxially. The inner catalyst tank 12 is close to reactor inner pipe 5. The top of the reactor inner pipe 5 is provided with a gas inlet 30 communicated to the flue gas inlet 6. The gas inlet 30 upwards protrudes from the catalyst storage tank 3. A side wall of the reactor inner pipe 5 also has a hollow net structure. The flue gas enters the reactor inner pipe 5 from the gas inlet 30 and enters the inner catalyst tank 12 from the hollow net structure. The bottom of the inner catalyst 501564 tank 12 is a sealed plate provided with a discharging pipeline. The bottom of the reactor inner pipe 5 is also a sealed structure. The flue gas in the reactor inner pipe 5 passes through the inner catalyst tank 12 and the outer catalyst tank 11 in a radial direction and then enters the flue gas overflow channel 10.

[0036] Referring to FIG. 2 to FIG. 4 on emphasis, a material turning member 4 is mounted in the inner catalyst tank 12. The material turning member 4 has a fork sheet capable of rotating in a reciprocating manner. When it is driven to rotate by a driving device, the fork sheet 15 can toggle the loose catalyst particles in the inner catalyst tank 12 to prevent agglomeration and deactivation, and the reaction area and reaction time between the flue gas and the catalyst are improved. The material turning member 4 further includes a main guide cylinder 16, an auxiliary guide cylinder 17, a driving shaft 18, a driven shaft 19, and a driving device. The fork sheet 15 includes two sliding arms and two tail arms 21 which are fixedly connected in a fork shape. The length of the sliding arm 20 is greater than that of the tail arm 20. An included angle of the two sliding arms 20 is 90 degrees. The two sliding arms 20 slidably penetrate through the main guide cylinder 16 and the auxiliary guide cylinder 17, respectively. Specifically, the main guide cylinder 16 and the auxiliary guide cylinder 17 are both provided with guide holes 22 adapted to the sliding arms 20. The sliding arms 20 are slidable along the guide holes 22.

[0037] One end of the driving shaft 18 and one end of the driven shaft 19 are respectively welded to outer walls of the main guide cylinder 16 and the auxiliary guide cylinder 17 and are perpendicular to the sliding arms 20. The outer walls of the left and right sides of the main guide cylinder 16 are welded with the driving shafts, and the outer walls of the left and right sides of the auxiliary guide cylinder 17 are welded with the driven shafts. The other ends of the driving shaft 18 and the driven shaft 19 are mounted on bearings in the reactor shell 1. The driving device is in driving connection to the driving shaft 18, and the driving device is mounted outside the reactor shell 1. The driving device includes a motor 23, a driving wheel 24, a driven wheel 25, a transmission wheel 26, and a belt 27. The motor 23 is mounted on a motor bracket on the reactor shell 1. An output shaft of the motor 23 is in driving connection to the 501564 driving wheel 24. The driving wheel 24 is engaged with the driven wheel 25. A pitch diameter of the driving wheel 24 is less than a pitch diameter of the driven wheel 25. Therefore, the fork sheet 15 can be slowly driven to rotate. The driven wheel 25 is in key connection to one driving shaft 18. The transmission wheel 26 is in key connection to other driving shafts. The belt 27 is tensioned to each driven wheel 25 and the transmission wheel 26 in an engaged manner

[0038] The motor 23 is a servo motor. The motor 23 drives, through the driving wheel 24, the driven wheel 25, the belt 27, and the transmission wheel 26, the respective fork sheets 15 to synchronously turn materials, thus improving the material turning efficiency. During material turning, the main guide cylinder 16 is driven by the motor 23 to drive the fork sheet 15 to rotate. The other sliding arm of the fork sheet 15 rotates with the sliding arm in the main guide cylinder 16, and this rotation inevitably causes the auxiliary guide cylinder 17 to rotate. The fork sheet inwards shrinks to slide along the guide hole of the auxiliary guide cylinder 17, so that the first sliding arm slides in an outwards extending manner along the guide hole of the main guide cylinder 16. Therefore, compared to an ordinary rotating vane, in the device, by means of the coordination between inwards shrinkage and outwards extension of the two sliding rams 20, the material turning range of the fork sheet 15 is enlarged, and the inwards shrinking sliding arm reduces the resistance to the sliding arm 20 when the catalyst is turned and ensures the work stability and flexibility. The tail arms 21 of the fork sheet further enlarge the material turning space of the fork sheet 15. Preferably, several pressure relief holes 31 are formed in the tail arms 21, which further reduces the resistance of the catalyst to the tail arms 21.

[0039] The motor 23 alternately rotates clockwise and anticlockwise to drive the fork sheet 15 to turn in a reciprocating manner. That is, when an intersection of the fork sheets is about to contact the main guide cylinder 16 or the auxiliary guide cylinder 17, an output of the motor 23 is reversed, achieving reciprocating flipping of the sliding arms 20 and avoiding that the intersection of the fork sheets interfere the movement of the sliding rams 20.

[0040] The material turning member 4 of the device is provided with the main guide HUS01564 cylinder 16 and the auxiliary guide cylinder 17. The two sliding arms 20 may slide along the corresponding guide cylinders, and only the main guide cylinder 16 is connected to the driving device to drive the auxiliary guide cylinder 17 to carry out follow-up rotation, which reduces the number of driving members, simplifies the structure of the device, and reduces the equipment cost.

[0041] The bottom of the catalyst storage tank 3 is supported in the reactor shell by a base. The base includes at least two supporting plates 28 arranged at an interval. Several ventilation holes 29 are formed in the supporting plates 28. The flue gas after the denitration enters the flue gas outlet 7 from a gap between the supporting plates 28 and the ventilation holes 29 in the supporting plates 28 and is then discharged out of the reactor shell 1.

[0042] The working principle of the device is as follows:

[0043] The spraying head 8 of the ammonia spraying grill is turned on to spray the gasified ammonia into the reactor shell 1, and the NOX and dust-containing flue gas after desulfurization enters the reactor shell 1 and reacts with the ammonia gas for denitration. The remaining SOX in the flue gas reacts with the ammonia gas to generate a small amount of ammonium salt.

[0044] The motor 23 is turned on to drive the material turning member 4 to flip back and forth.

[0045] The flue gas enters the reactor inner pipe 5 and firstly performs SCR reaction with the catalyst particles in the inner catalyst tank 12 to pre-remove part of the ammonium salt and adsorb the dust. The sliding arms 20 of the fork sheet 15 toggle the catalyst particles in a reciprocating manner to prevent agglomeration and deactivation of the catalyst, which enlarges the contact area between the catalyst particles and the flue gas and disturbs the flow direction of the flue gas. It further prolongs the contact time between the flue gas and the catalyst particles and is conductive to cooling the flue gas.

[0046] The flue gas flows along the radial direction and enters the outer catalyst tank 11 from the inner catalyst tank 12. The ammonia-removed salt is continuously adsorbed by the catalyst particles to obtain a cleaner gas flow.

[0047] The gas flow enters the flue gas overflow channel 10 from the outer catalyst HUS01564 tank 11, flows downwards under the action of an external induced draft fan, enters the flue gas outlet 7 through the gap between the supporting plates 28 and the ventilation holes 29 in the supporting plates, and is discharged out of the reactor shell 1. The average temperature of the flue gas after denitration is 155-170°C.

[0048] Embodiment 2

[0049] As shown in FIG. 5, a difference between this embodiment and Embodiment 1 lies in a different structure of the base. The base of this embodiment includes a plurality of arc-shaped diversion plates 32. The diversion plates 32 are arranged along a spiral track, and an air inlet gap 33 is reserved between adjacent diversion plates 32 on the spiral track. The gas flow flowing out of the flue gas overflow channel 10 passes through the air inlet gap 33, then quickly flows into the flue gas outlet 7 along the spiral track, and is pumped into a chimney through an induced draft fan. Several ventilation holes 29 are also formed in one circle of diversion plate on the outermost side, so that it is convenient for the gas flow in the flue gas overflow channel 10 to enter the spiral track of the inner circle from the ventilation holes 29.

[0050] The above descriptions are only preferred embodiments of the present disclosure and are not intended to limit the present disclosure. Although the present disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions in the foregoing various embodiments, or equivalently replace partial technical features. Any modifications, equivalent replacements, improvements, and the like that are made within the spirit and principle of the present disclosure shall all fall within the protection scope of the present disclosure.

Claims

CLAIMS LU501564

1. A selective catalytic reduction (SCR) low-temperature denitration device, comprising: a reactor shell which has a flue gas inlet and a flue gas outlet; an ammonia spraying grille on which a spraying head communicated to an ammonia spraying pipeline is mounted, a catalyst storage tank which is fixed in the reactor shell and is located below the ammonia spraying grille, a flue gas overflow channel being reserved between a catalyst storage tank and an inner side wall of the reactor shell; the flue gas overflow channel being communicated to the flue gas outlet; the catalyst storage tank comprising an outer catalyst tank and an inner catalyst tank located in the outer catalyst tank; a material turning member being mounted in the inner catalyst tank; the material turning member having a fork sheet capable of rotating in a reciprocating manner, when rotating, the fork sheet toggling catalyst particles in the inner catalyst tank; a reactor inner pipe which is located in the middle of the outer catalyst tank and extends in a longitudinal direction, the inner catalyst tank being clung to the reactor inner pipe; a top of the reactor inner pipe being provided with a gas inlet communicated to the flue gas inlet; a bottom of the reactor inner pipe being of a sealed structure; flue gas entering the reactor inner pipe from the gas inlet passing through the inner catalyst tank and the outer catalyst tank in a radial direction and entering the flue gas overflow channel.

2. The SCR low-temperature denitration device according to claim 1, wherein the material turning member further comprises a main guide cylinder, an auxiliary guide cylinder, a driving shaft, a driven shaft, and a driving device; two sliding arms of the fork sheet respectively slidably penetrate through the main guide cylinder and the auxiliary guide cylinder; the driving shaft and the driven shaft are fixedly connected to the main guide cylinder and the auxiliary guide cylinder, respectively; the driving shaft and the driven shaft are both mounted on the reactor shell; and the driving device is in driving connection to the driving shaft; and the driving device is mounted outside the reactor shell.

3. The SCR low-temperature denitration device according to claim 2, wherein the HUS01564 fork sheet further comprises two tail arms; the two tail arms and the two sliding arms are connected with each other to form a fork structural body; the main guide cylinder and the auxiliary guide cylinder are both provided with guide holes adapted to the sliding arms; and the sliding arms are slidable along the guide holes.

4. The SCR low-temperature denitration device according to claim 2, wherein an included angle between the two sliding arms is 90 degrees.

5. The SCR low-temperature denitration device according to claim 3, wherein a length of the sliding arm is greater than that of the tail arm.

6. The SCR low-temperature denitration device according to claim 2, wherein the driving device comprises a motor, a driving wheel, a driven wheel, a transmission wheel, and a belt; the motor is in driving connection to the driving wheel; the driving wheel is engaged with the driven wheel; a pitch diameter of the driving wheel is less than a pitch diameter of the driven wheel; the driven wheel is in key connection to one driving shaft; the transmission wheel is in key connection to other driving shafts; and the belt is tensioned to the driven wheel and the transmission wheel in an engaged manner.

7. The SCR low-temperature denitration device according to any one of claims 1 to 6, wherein a mounting baffle plate is fixed at the top of the catalyst storage tank; the baffle plate prevents flue gas from entering the catalyst storage tank from the top of the catalyst storage tank; and the baffle plate is fixed on the inner wall of the reactor shell.

8. The SCR low-temperature denitration device according to any one of claims 1 to 6, wherein side walls of the outer catalyst tank and the inner catalyst tank are provided with hollow net structures; a mesh of the hollow net structure is less than a particle size of the catalyst particle; the outer catalyst tank is closely filled with the catalyst particles; and the inner catalyst tank is loosely filled with the catalyst particles.

9. The SCR low-temperature denitration device according to any one of claims 1 to 6, wherein an agent feeding pipe and an agent discharging pipe are respectively mounted at the top and bottom of the catalyst storage tank; and the other end of the agent feeding pipe and the other end of the agent discharging pipe respectively penetrate through the top and bottom of the reactor shell.

0 . . . LU501564

10. The SCR low-temperature denitration device according to any one of claims 1 to 6, wherein the bottom of the catalyst storage tank is supported on the reactor shell by a base; the base comprises at least two supporting plates arranged at an interval; and a plurality of ventilation holes are formed in the supporting plates.