CN112747121B

CN112747121B - Sealing structure of gate valve type bottom cover machine and operation method thereof

Info

Publication number: CN112747121B
Application number: CN201911041758.9A
Authority: CN
Inventors: 张欣; 杨成炯
Original assignee: Sinopec Engineering Group Co Ltd; Sinopec Guangzhou Engineering Co Ltd
Current assignee: Sinopec Engineering Group Co Ltd; Sinopec Guangzhou Engineering Co Ltd
Priority date: 2019-10-30
Filing date: 2019-10-30
Publication date: 2022-05-10
Anticipated expiration: 2039-10-30
Also published as: CN112747121A

Abstract

The invention discloses a sealing structure of a gate valve type bottom cover machine and an operation method thereof. The sealing structure comprises a pressing ring, a valve seat ring and a spring assembly. The valve body is provided with a first channel, and an outlet of the first channel is communicated with a gap between the upper surface of the valve seat ring and the lower surface of the convex shoulder of the pressing ring and then communicated with an inner cavity of the valve body above the valve plate through a gap between the inner side surface of the valve seat ring and the outer side surface of the central cylinder of the pressing ring. A primary filler, a secondary filler and a spacer ring are arranged between the outer side part of the valve seat ring and the side surface of the inner cavity of the valve body. The valve body is provided with a second channel, and the outlet of the second channel is communicated with the outer ring groove on the spacer ring. And a third channel is arranged on the valve seat ring, the inlet of the third channel is communicated with the inner ring groove on the spacer ring, and the outlet of the third channel is communicated with the throttling groove at the bottom of the valve seat ring. The invention discloses an operation method of the sealing structure. The invention is mainly used for the shutter valve type bottom cover machine used for the coke tower of the delayed coking device of the oil refinery.

Description

Sealing structure of gate valve type bottom cover machine and operation method thereof

Technical Field

The invention relates to a sealing structure of a gate valve type bottom cover machine for a coke tower of a delayed coking device of an oil refinery and an operation method thereof.

Background

In the delayed coking unit in oil refinery, bottom cover machines are set at the bottom of coke tower. The bottom capping machine has various structural forms, and in recent years, a novel gate valve type automatic bottom capping machine is widely used. Because the coke oven can be totally closed from the bottom of the coke oven to the coke storage tank or the dewatering bin, the operation safety is obviously improved, the operation environment is improved, the opening and closing operation is simple and easy, and the labor intensity of the decoking work is greatly reduced. The novel gate valve type bottom cover machine is provided with an actuating mechanism, a valve body, a lower flange, a rear valve cover, a pressing ring, a floatable valve seat ring, a valve plate, a spring assembly, a front valve cover, a valve rod and the like, wherein the actuating mechanism drives the valve rod and drives the valve plate to do linear motion, so that the bottom cover machine is opened and closed. The valve plate is of a flow guide hole type structure, and the seal between the valve plate and the valve seat ring is an elastic metal-to-metal hard seal structure. Be equipped with steam flow path on the valve body, steam flow path's entry links to each other with the export of steam line, and steam flow path's export communicates with each other with the clearance between the upper surface of valve seat circle and the evagination circular bead lower surface of clamping ring, then communicates with each other with the inner chamber of the valve body of valve plate top through the clearance between the medial surface of valve seat circle and the lateral surface of clamping ring center section of thick bamboo. The reaction medium entering the coke tower is vacuum residue oil or oil slurry, etc., and coke is formed and heat cracking reaction is carried out in the coke tower. In the coke-producing stage of the coke tower, the gate valve type bottom cover machine is closed, and steam is introduced into the steam channel from the steam pipeline. Steam sweeps the inner chamber of the valve body above the valve plate through the clearance between the upper surface of the valve seat ring and the lower surface of the convex shoulder of the pressing ring and then through the clearance between the inner side surface of the valve seat ring and the outer side surface of the central cylinder of the pressing ring, and then enters the coke tower through the opening of the valve body. The steam has the function of preventing heavy oil media such as high-temperature and easily-coked vacuum residue oil or oil slurry and the like from flowing between the valve seat ring and the pressing ring and at the spring assembly to prevent coking or blockage, so that the elasticity of the valve seat ring is damaged, and the operating performance of the bottom cover machine is further influenced and damaged. However, since a large amount of steam enters the coke drum, the gas velocity in the coke drum tends to be too high, and the quality of high-quality coke (for example, needle coke) produced by the coke drum is degraded.

Disclosure of Invention

The invention aims to provide a sealing structure of a gate valve type bottom cover machine and an operation method thereof, which aim to solve the problems that in the prior art, the gas velocity in a coke tower is too high and the quality of high-quality coke is reduced due to the fact that a large amount of sealing purging steam enters the coke tower.

In order to solve the problems, the invention adopts the technical scheme that: the utility model provides a seal structure of flashboard valve formula bottom cap machine, including clamping ring and the valve seat circle of locating among the valve body inner chamber, be equipped with the valve body trompil on the valve body, be equipped with spring assembly between the evagination circular bead of clamping ring and the upper portion of valve seat circle, leave the clearance between the medial surface of valve seat circle and the lateral surface of clamping ring center tube, the lower surface of valve seat circle is through the upper surface jam of the pressure of the interior oil gas medium of spring force and coke drum and valve plate, the bottom of valve seat circle is equipped with the throttle groove, be equipped with first passageway on the valve body, the entry of first passageway links to each other with the export of first pipeline, the export of first passageway communicates with each other with the clearance between the upper surface of valve seat circle and the evagination circular bead lower surface of clamping ring, the inner chamber of valve body above the valve plate communicates with each other through the clearance between the medial surface of valve seat circle and the lateral surface of clamping ring center tube then, its characterized in that: the valve body is provided with a first-stage filler and a second-stage filler, the first-stage filler is positioned above the second-stage filler, a spacer ring is arranged between the first-stage filler and the second-stage filler, the spacer ring is provided with an outer ring groove and an inner ring groove, the outer ring groove is communicated with the inner ring groove through a spacer ring through hole, the valve body is provided with a second channel, an inlet of the second channel is connected with an outlet of a second pipeline, an outlet of the second channel is communicated with the outer ring groove on the spacer ring, the valve seat ring is provided with a third channel, an inlet of the third channel is communicated with the inner ring groove on the spacer ring, and an outlet of the third channel is communicated with a throttling groove.

The operation method of the sealing structure of the gate valve type bottom cover machine is characterized in that: in the coke-producing stage of the coke tower, the flashboard valve type bottom cover machine is closed, the valve plate seals the valve body open hole on the valve body, wax oil is introduced into the first channel from the first pipeline, the wax oil is blown to the inner cavity of the valve body above the valve plate through the gap between the upper surface of the valve seat ring and the lower surface of the convex shoulder of the pressing ring and then through the gap between the inner side surface of the valve seat ring and the outer side surface of the pressing ring central cylinder, and then enters the coke tower through the valve body open hole, meanwhile, steam is introduced into the second channel from the second pipeline, the steam enters the third channel through the outer ring groove, the spacer ring through hole and the inner ring groove on the spacer ring and then enters the throttling groove from the third channel, after the steam in the throttling groove enters the gap between the lower surface of the valve seat ring and the upper surface of the valve plate, one part of steam is leaked inwards to an inner cavity of the valve body above the valve plate and then enters the coke drum through the opening of the valve body, and the other part of steam is leaked outwards to inner cavities of the front valve cover and the rear valve cover outside the valve body.

The invention has the following beneficial effects: (1) in the coking stage of the coke tower, wax oil is introduced into the first passage and flows according to the path, so that heavy oil media such as high-temperature and coking-prone vacuum residue oil or slurry oil and the like can be prevented from flowing between the valve seat ring and the pressing ring and at the spring assembly, coking or blocking is prevented, the elasticity of the valve seat ring is damaged, and the operating performance of the bottom cover machine is influenced and damaged. (2) The property of the introduced wax oil medium is similar to that of the high-temperature vacuum residue oil or oil slurry and other media, so that the gas velocity in the coke tower is not too high, and the side effect of reducing the quality of the coke is not caused. (3) The pressure of steam in the second pipeline is higher than the pressure of wax oil in the first pipeline, so that the wax oil can be effectively prevented from entering a gap between the lower surface of the valve seat ring and the upper surface of the valve plate and then leaking to the inner cavities of the front valve cover and the rear valve cover outside the valve body and even leaking to the atmosphere, and fire hazard is caused. (4) Compared with the prior art, wax oil is introduced into the first channel and is used as a sealing purging medium of the gate valve type bottom cover machine in the coke-producing stage of the coke tower. The amount of steam introduced into the second channel from the second pipeline can be reduced as much as possible, and because the lower surface of the valve seat ring is tightly pressed against the upper surface of the valve plate, only a small amount of steam enters the coke tower, a large amount of steam can not enter the coke tower. The gas speed in the coke tower is easy to control and not too high, thereby preventing the quality of high-quality coke (such as needle coke) produced by the coke tower from being reduced and meeting the technical production operation requirement of the high-quality coke.

The invention is mainly used for the shutter valve type bottom cover machine used for the coke tower of the delayed coking device of the oil refinery.

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. The drawings and detailed description do not limit the scope of the invention as claimed.

Drawings

Fig. 1 is a cross-sectional view of a seal structure of a gate valve type bottom cap machine of the present invention.

Fig. 2 is a schematic diagram of a sealed purge medium delivery and differential pressure control system for the seal structure of a gate valve type bottom cap machine of the present invention.

In fig. 1 and 2, the same reference numerals denote the same technical features. The reference numerals in fig. 1 and 2 denote: 1. pressing a ring; 2. a valve body; 21. opening a hole in the valve body; 3. a valve seat ring; 31. a throttling groove; 4. a gland; 51. first-stage filling; 52. secondary filling; 6. a spacer ring; 71. a guide sleeve; 72. a guide bar; 73. a spring; 81. a first channel; 82. a second channel; 83. a third channel; 91. a first pipeline; 92. a second pipeline; 10. a valve plate; 11. a differential pressure monitoring instrument; 111. a first differential pressure monitoring instrument line; 112. a second differential pressure monitoring instrument line; 12. adjusting a valve; 13. a check valve; 14. a shut-off valve; 151. a first pressure gauge; 152. a second pressure gauge; 16. and a signal line.

Detailed Description

Referring to fig. 1 and 2, the sealing structure (simply referred to as sealing structure) of the gate valve type bottom cap machine of the present invention includes a pressing ring 1 and a valve seat ring 3 provided in an inner cavity of a valve body 2. The valve body 2 is provided with a valve body opening 21, and a spring component is arranged between the convex shoulder of the pressing ring 1 and the upper part of the valve seat ring 3. A gap is reserved between the upper surface of the valve seat ring 3 and the lower surface of the convex shoulder of the pressing ring 1, and a gap is reserved between the inner side surface of the valve seat ring 3 and the outer side surface of the central cylinder of the pressing ring 1 and communicated with the inner cavity of the valve body 2 above the valve plate 10. The lower surface of the valve seat ring 3 is pressed with the upper surface of the valve plate 10 through spring force and pressure of oil-gas medium in the coke tower to form metal hard seal; normally there is only a small gap between the two surfaces. The bottom of the seat ring 3 is provided with a throttling groove 31. The valve body 2 is provided with a first channel 81, the inlet of the first channel 81 is connected with the outlet of the first pipeline 91, the outlet of the first channel 81 is communicated with the gap between the upper surface of the valve seat ring 3 and the lower surface of the outer convex shoulder of the pressing ring 1, and then communicated with the inner cavity of the valve body 2 above the valve plate 10 through the gap between the inner side surface of the valve seat ring 3 and the outer side surface of the central cylinder of the pressing ring 1.

The spring assembly includes a spring 73, a guide rod 72 and a guide sleeve 71. The spring 73 is arranged in a blind hole at the upper part of the valve seat ring 3 and sleeved outside the guide rod 72. The guide sleeve 71 is arranged between the top of the spring 73 and the lower surface of the convex shoulder of the pressing ring 1. The spring assembly is provided in plural number and arranged uniformly around the axial center line of the valve body opening 21. And all or at least a part of the spring assembly, wherein the top of the guide rod 72 is connected with the convex shoulder of the pressing ring 1 through a bolt and a nut, so that the tensile force of the spring 73 along the axial direction of the guide rod 72 is adjusted, and the lower surface of the valve seat ring 3 is pressed on the upper surface of the valve plate 10.

A primary packing 51 and a secondary packing 52 are arranged between the outer side part of the valve seat ring 3 and the side surface of the inner cavity of the valve body 2, and the primary packing 51 is positioned above the secondary packing 52 and is installed in series. A spacer ring 6 is arranged between the first-stage packing 51 and the second-stage packing 52, an outer ring groove and an inner ring groove are arranged on the spacer ring 6, and the outer ring groove and the inner ring groove are communicated through spacer ring through holes. A second channel 82 is arranged below the first channel 81 on the valve body 2, the inlet of the second channel 82 is connected with the outlet of the second pipeline 92, and the outlet of the second channel 82 is communicated with the outer ring groove on the spacer ring 6. The valve seat ring 3 is provided with a third channel 83, the inlet of the third channel 83 is communicated with the inner ring groove on the spacer ring 6, and the outlet of the third channel 83 is communicated with the throttling groove 31.

The material of the primary filler 51 and the secondary filler 52 is generally flexible graphite, or a material having equivalent properties. The material of the spacer ring 6 is generally stainless steel, or a heat-resistant metal material having equivalent properties. A packing groove is generally formed between the outer side of the seat ring 3 and the side of the inner cavity of the valve body 2, and the primary packing 51, the secondary packing 52 and the spacer ring 6 are all placed in the packing groove. The sealing structure is provided with a packing gland 4, wherein the packing gland 4 compresses a secondary packing 52 contacted with the packing gland 4 and compresses a primary packing 51 through a spacer ring 6. The gland 4 is fixed to the seat ring 3 by bolts.

The valve body opening 21 of the valve body 2 is a circular hole. The pressing ring 1, the valve seat ring 3, the primary packing 51, the secondary packing 52, the spacer ring 6 and the packing gland 4 are all in a rotary body shape, and the axial lead is coaxial with the axial lead of the valve body opening 21. The overall shapes of the throttling groove 31 and the outer ring groove and the inner ring groove on the spacer ring 6 are both circular rings, and the axial lead is coaxial with the axial lead of the valve body opening 21. The first channel 81, the second channel 82 and the third channel 83 are all straight channels with circular cross sections, the spacer ring through holes on the spacer ring 6 are straight holes with circular cross sections, and the cross section of the throttling groove 31 is rectangular and is opened downwards.

The number of the first channels 81 and the number of the second channels 82 are generally 1-2 respectively; when 2, the holes are uniformly arranged around the axial lead of the valve body opening 21. The third channel 83 is generally provided with 4-8, the spacer ring through holes on the spacer ring 6 are generally provided with 4-16, and the spacer ring through holes are uniformly distributed around the axial lead of the valve body opening 21. The number of the throttling grooves 31 is generally 2-5, and the throttling grooves are concentrically arranged. A third channel 83, the outlet of which communicates with a throttle groove 31; the outlet of the different third channel 83, may communicate with the same or with different throttle grooves 31.

Referring to fig. 2, in the system for controlling the delivery and differential pressure of the sealing purging medium according to the present invention, a shut-off valve 14, a check valve 13 and a first pressure gauge 151 are sequentially disposed on a first pipeline 91 from an inlet to an outlet of the first pipeline 91, and a valve bank of a regulating valve 12 and a second pressure gauge 152 are sequentially disposed on a second pipeline 92 from an inlet to an outlet of the second pipeline 92. The first pipeline 91 is connected to the differential pressure monitoring instrument 11 (for example, a differential pressure transmitter) through the first differential pressure monitoring instrument pipeline 111, the second pipeline 92 is connected to the differential pressure monitoring instrument 11 through the second differential pressure monitoring instrument pipeline 112, and a signal line 16 is provided between the differential pressure monitoring instrument 11 and the regulating valve 12.

When the flashboard valve type bottom cover machine adopting the sealing structure of the invention is used, the valve body opening 21 on the valve body 2 is communicated with the discharge hole at the bottom of the coke tower through a flange.

The operation of the sealing structure of the present invention will be described with reference to the accompanying drawings. In the coke drum coke-forming stage, the gate valve type bottom cover machine is closed (as shown in fig. 1), and the valve plate 10 closes the valve body opening 21 on the valve body 2. Wax oil is introduced into the first channel 81 from the first pipeline 91, and the wax oil is blown to an inner cavity of the valve body 2 above the valve plate 10 through a gap between the upper surface of the valve seat ring 3 and the lower surface of the convex shoulder of the pressing ring 1 and then through a gap between the inner side surface of the valve seat ring 3 and the outer side surface of the central cylinder of the pressing ring 1, and then enters the coke tower through the valve body opening 21. Meanwhile, steam is introduced into the second channel 82 from the second pipeline 92, enters the third channel 83 through the outer ring groove, the spacer ring through hole and the inner ring groove on the spacer ring 6, and then enters the throttling groove 31 from the third channel 83. After steam in the throttling groove 31 enters a gap between the lower surface of the valve seat ring 3 and the upper surface of the valve plate 10, a part of steam is leaked inwards to an inner cavity of the valve body 2 above the valve plate 10 and then enters a coke tower through the valve body opening 21, and the other part of steam is leaked outwards to inner cavities of a front valve cover and a rear valve cover outside the valve body 2.

The steam mentioned in the invention is water steam, and the wax oil is wax oil produced by a petroleum processing device. The pressure of the steam is higher than that of the wax oil, and the pressure of the steam in the second pipeline 92 is generally 0.05-0.2 MPa higher than that of the wax oil in the first pipeline 91. The pressure of the steam and the wax oil is higher than the pressure of the reaction medium in the coke tower. Referring to fig. 2, the pressure difference monitor 11 measures the pressure of the wax oil in the first pipeline 91 and the pressure of the steam in the second pipeline 92, monitors the pressure difference between the two pressures and transmits a signal through the signal line 16, and adjusts the pressure of the steam in the second pipeline 92 by adjusting the opening of the adjusting valve 12, so that the pressure of the steam is always higher than the pressure of the wax oil in the first pipeline 91 and the pressure difference is kept constant. When the differential pressure decreases to a lower value, the differential pressure monitoring instrument 11 will send out an alarm signal. When the pressure difference is further reduced to a lower value, the pressure difference monitoring instrument 11 can send out an alarm signal, and meanwhile, the control valve 12 is fully opened or operation measures such as device interlocking and control are taken to ensure the operation safety of the delayed coking device.

And after the coke forming stage of the coke tower is finished, switching to a coke cooling stage. At this point the coke drum stops feeding and the coke drum is disconnected from the fractionation system and the gate valve bottom head machine is still closed. The sealing purging medium introduced into the first channel 81 from the first pipeline 91 is switched from wax oil to steam, and the steam is purged to the inner cavity of the valve body 2 above the valve plate 10 through a gap between the upper surface of the valve seat ring 3 and the lower surface of the outer convex shoulder of the pressing ring 1 and then through a gap between the inner side surface of the valve seat ring 3 and the outer side surface of the central cylinder of the pressing ring 1 and then enters the coke tower through the valve body opening 21. At the same time, steam continues to be introduced into the second passage 82 from the second line 92 in the same flow path as the steam introduced into the second passage 82 from the second line 92 during the coke drum coking stage.

And after the coke cooling stage of the coke tower is finished, switching to a decoking stage, opening the gate valve type bottom cover machine, and communicating the valve plate hole on the valve plate 10 with the valve body hole 21 on the valve body 2. Steam is introduced into the first passage 81 from the first line 91, and the steam is purged to the inner cavity of the valve body 2 above the valve plate 10 through a gap between the upper surface of the valve seat ring 3 and the lower surface of the outer convex shoulder of the pressure ring 1 and then through a gap between the inner side surface of the valve seat ring 3 and the outer side surface of the central cylinder of the pressure ring 1. Then, a part of steam in the inner cavity of the valve body 2 enters the coke tower through the valve body opening 21, and the other part of steam enters a coke storage tank or a dewatering bin at the downstream through the valve plate holes on the valve plate 10. At the same time, steam continues to be passed from the second line 92 to the second passage 82. Steam enters the third channel 83 through the outer ring groove, the spacer ring through hole and the inner ring groove on the spacer ring 6 and then enters the throttling groove 31 from the third channel 83. After steam in the throttling groove 31 enters a gap between the lower surface of the valve seat ring 3 and the upper surface of the valve plate 10, a part of steam is leaked inwards to an inner cavity of the valve body 2 above the valve plate 10, and the other part of steam is leaked outwards to inner cavities of the front valve cover and the rear valve cover outside the valve body 2. The steam leaked into the inner cavity of the valve body 2 above the valve plate 10 partially enters the coke tower through the valve body opening 21, and the other part enters a coke storage pool or a dewatering bin at the downstream through the valve plate hole on the valve plate 10.

In the steam purging process of the coke cooling stage and the decoking stage of the coke tower, the pressure of the steam in the second pipeline 92 is preferably 0.005-0.01 MPa higher than that of the steam in the first pipeline 91; the steam pressure in the two lines may also be equal. Since the pressure difference of the steam is small or equal, the consumption of the steam can be reduced.

Claims

1. The sealing structure of the gate valve type bottom cover machine comprises a pressing ring (1) and a valve seat ring (3) which are arranged in an inner cavity of a valve body (2), a valve body opening (21) is formed in the valve body (2), a spring assembly is arranged between an outer convex shoulder of the pressing ring (1) and the upper portion of the valve seat ring (3), a gap is reserved between the inner side surface of the valve seat ring (3) and the outer side surface of a central cylinder of the pressing ring (1), the lower surface of the valve seat ring (3) is tightly pressed with the upper surface of a valve plate (10) through spring force and pressure of oil and gas media in a coke tower, a throttling groove (31) is formed in the bottom of the valve seat ring (3), a first channel (81) is formed in the valve body (2), an inlet of the first channel (81) is connected with an outlet of a first pipeline (91), an outlet of the first channel (81) is communicated with the gap between the upper surface of the valve seat ring (3) and the outer convex shoulder lower surface of the pressing ring (1), Then the clearance between the lateral surface through the medial surface of valve seat circle (3) and clamping ring (1) center section of thick bamboo communicates with each other with the inner chamber of valve body (2) above valve plate (10), its characterized in that: a first-stage filler (51) and a second-stage filler (52) are arranged between the outer side of a valve seat ring (3) and the side face of an inner cavity of a valve body (2), the first-stage filler (51) is located above the second-stage filler (52), a spacer ring (6) is arranged between the first-stage filler (51) and the second-stage filler (52), an outer ring groove and an inner ring groove are arranged on the spacer ring (6), the outer ring groove is communicated with the inner ring groove through a spacer ring through hole, a second channel (82) is arranged on the valve body (2), an inlet of the second channel (82) is connected with an outlet of a second pipeline (92), an outlet of the second channel (82) is communicated with the outer ring groove on the spacer ring (6), a third channel (83) is arranged on the valve seat ring (3), an inlet of the third channel (83) is communicated with the inner ring groove on the spacer ring (6), an outlet of the third channel (83) is communicated with a throttling groove (31), and a stop valve (14) are sequentially arranged from the inlet to the outlet of the first pipeline (91), Check valve (13) and first manometer (151), be equipped with the valves group and second manometer (152) of governing valve (12) in proper order from the entry to the export of second pipeline (92) on second pipeline (92), the pipeline section that first pipeline (91) are located between check valve (13) and first manometer (151) links to each other with pressure difference monitoring instrument (11) through first pressure difference monitoring instrument pipeline (111), the pipeline section that second pipeline (92) are located between the valves group of governing valve (12) and second manometer (152) links to each other with pressure difference monitoring instrument (11) through second pressure difference monitoring instrument pipeline (112), be equipped with signal line (16) between pressure difference monitoring instrument (11) and governing valve (12).

2. A seal structure of a gate valve type bottom cap machine according to claim 1, wherein: the sealing structure is provided with a packing gland (4), the packing gland (4) compresses a secondary packing (52) contacted with the packing gland, and the primary packing (51) is compressed through a spacer ring (6).

3. A seal structure of a gate valve type bottom cap machine according to claim 1, wherein: the first channel (81) and the second channel (82) are respectively provided with 1-2, the third channel (83) is provided with 4-8, the spacer ring through holes on the spacer ring (6) are provided with 4-16, and the throttling groove (31) is provided with 2-5.

4. The seal structure of a shutter valve type bottom cap machine according to claim 1, wherein: the differential pressure monitoring instrument (11) is a differential pressure transmitter.

5. The method of operating a seal structure for a gate valve type under cap machine according to claim 1, wherein: in the coke-producing stage of the coke tower, the gate valve type bottom cover machine is closed, the valve plate (10) closes a valve body open hole (21) on the valve body (2), wax oil is introduced into a first channel (81) from a first pipeline (91), the wax oil passes through a gap between the upper surface of the valve seat ring (3) and the lower surface of an outer convex shoulder of the pressing ring (1), then is swept to an inner cavity of the valve body (2) above the valve plate (10) through a gap between the inner side surface of the valve seat ring (3) and the outer side surface of a central cylinder of the pressing ring (1), and then enters the coke tower through the valve body open hole (21), meanwhile, steam is introduced into a second channel (82) from a second pipeline (92), enters a third channel (83) through an outer ring groove, a spacer ring through hole and an inner ring groove on the spacer ring (6), then enters a throttling groove (31) from the third channel (83), and the steam in the throttling groove (31) enters a gap between the lower surface of the ring (3) and the upper surface of the valve plate (10), one part of steam is leaked inwards to the inner cavity of the valve body (2) above the valve plate (10) and then enters the coke tower through the valve body opening (21), and the other part of steam is leaked outwards to the inner cavities of the front valve cover and the rear valve cover outside the valve body (2).

6. The operating method according to claim 5, characterized in that: the pressure of the steam in the second pipeline (92) is 0.05-0.2 MPa higher than that of the wax oil in the first pipeline (91).

7. Operating method according to claim 5 or 6, characterized in that: after the coke-forming stage of the coke tower is finished, the coke-cooling stage is switched, the sealing purging medium led into the first channel (81) from the first pipeline (91) is switched into steam from wax oil, the steam is purged to the inner cavity of the valve body (2) above the valve plate (10) through a gap between the upper surface of the valve seat ring (3) and the lower surface of the convex shoulder of the pressing ring (1) and then through a gap between the inner side surface of the valve seat ring (3) and the outer side surface of the central cylinder of the pressing ring (1), and then enters the coke tower through the valve body opening (21), meanwhile, the steam is continuously led into the second channel (82) from the second pipeline (92), and the flow path of the steam is the same as the flow path of the steam led into the second channel (82) from the second pipeline (92) in the coke-forming stage of the coke tower.

8. The operating method according to claim 7, characterized in that: after the coke cooling stage of the coke tower is finished, the coke cooling stage is switched to a coke removing stage, a gate valve type bottom cover machine is opened, a valve plate hole in a valve plate (10) is communicated with a valve body open hole (21) in a valve body (2), steam is introduced into a first channel (81) from a first pipeline (91), the steam passes through a gap between the upper surface of a valve seat ring (3) and the lower surface of an outer convex shoulder of a pressing ring (1) and then passes through a gap between the inner side surface of the valve seat ring (3) and the outer side surface of a central cylinder of the pressing ring (1) to be swept to an inner cavity of the valve body (2) above the valve plate (10), then, part of the steam enters the coke tower through the valve body open hole (21), the other part of the steam enters a downstream coke storage tank or a dehydration bin through the valve plate hole in the valve plate (10), meanwhile, the steam continues to be introduced into a second channel (82) from a second pipeline (92), and the steam passes through an outer ring groove in a spacer ring (6), The spacer ring through hole and the inner ring groove enter the third channel (83), and then enter the throttling groove (31) from the third channel (83), after steam in the throttling groove (31) enters a gap between the lower surface of the valve seat ring (3) and the upper surface of the valve plate (10), one part of steam is leaked inwards to the inner cavity of the valve body (2) above the valve plate (10), the other part of steam is leaked outwards to the inner cavities of the front valve cover and the rear valve cover outside the valve body (2), the steam leaked to the inner cavity of the valve body (2) above the valve plate (10) enters the coke tower through the valve body opening hole (21), and the other part of steam enters a downstream coke storage tank or a dehydration bin through the valve plate hole on the valve plate (10).

9. The operating method according to claim 8, characterized in that: the pressure of the steam in the second pipeline (92) is 0.005-0.01 MPa higher than that of the steam in the first pipeline (91).