A water sealed can without pressure drop

Abstract

The application discloses a water seal tank without pressure drop, which can replace all local resistance links in the prior art with a small local resistance link under the premise of guaranteeing sealing effect, and realizes the requirement of sealing and energy saving at the same time. The water seal tank without pressure drop comprises a cylindrical tank body, a flue gas outlet arranged at the top of the tank body, a flue gas inlet arranged at the middle side of the tank body, a float arranged in the tank body, a 90-degree elbow arranged through the upper part of the float, an annular cylinder arranged outside the outer ring of the upper opening of the elbow, an annular bottom plate arranged between the upper part of the elbow and the float, a flue gas outlet pipeline with one end extending into the float, an elbow outlet extending into the flue gas outlet pipeline, and a zigzag annular channel formed by the upper part of the elbow, the annular cylinder, the bottom plate and the extending part in the flue gas outlet pipeline. The zigzag annular channel is a water seal groove, and the float moves up and down in the tank body by increasing and reducing the sealing water in the water seal groove.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalytic cracking in petroleum chemical industry, and relates to a pressure-free water seal tank used for gas sealing on a regeneration flue gas pipeline of a catalytic cracking unit. BACKGROUND

[0002] In a regeneration flue gas energy recovery system of a catalytic cracking unit in the petroleum chemical industry, in order to realize complete sealing of the pipeline and equipment after being cut off to ensure safe maintenance of the subsequent equipment and pipeline, and considering economy, a cut-off mode of a high-temperature butterfly valve cooperating with a water seal tank is generally adopted. In order to achieve the maximum flue gas energy recovery effect, it is usually required that the pressure drop of the water seal tank is reduced to the minimum. The commonly used water seal tank is provided with a regeneration flue gas side opening and an upper opening of a cylindrical body, and a pipeline connected with the upper opening penetrates into the inside of the cylindrical body, and the end surface thereof is close to the bottom of the cylindrical body. The resistance of the commonly used water seal tank is caused by the following several links: 1) sudden change of cross section (sudden expansion or sudden reduction); 2) flow around the cylindrical body; 3) gap flow; and 4) 180° turn. The pressure drop of the water seal tank is relatively large, and under the condition that the flow rate in the tank is the same as that of the pipeline, the pressure drop of the water seal tank is about 500-800 Pa.

[0003] In order to improve the problems of the above-mentioned commonly used water seal tank, a low-pressure drop water seal valve is proposed in Chinese patent ZL200820069755.7. The central content of the patent is that a floating valve core that can float up and down is arranged in the inside of a cylindrical body to replace the pipeline of the upper opening of the existing water seal tank penetrating into the inside of the cylindrical body. The technology replaces the pipeline in the existing water seal tank with the floating valve core, reduces the three local resistance links of flow around the cylindrical body, gap flow and 180° turn, but increases the resistance loss caused by vortex flow due to the direct collision of flue gas with the wall, the maximum sudden change of cross section resistance drop still exists, and the overall improvement effect is limited. SUMMARY

[0004] The present application proposes a new pressure-free water seal tank aiming at the shortcomings of the prior art. The pressure-free water seal tank has special structural features, can replace the local resistance links in the prior art with a small local resistance link (usually about 14 Pa) under the premise of ensuring the sealing effect, and realizes the process requirements of sealing and energy saving at the same time.

[0005] The application provides a water seal tank without pressure drop, characterized in that the water seal tank without pressure drop comprises a cylindrical tank body, a flue gas outlet is arranged at the top of the cylindrical tank body, a water seal inlet is arranged on the upper part or the top of the tank body, a flue gas inlet is arranged on the side of the middle part of the tank body, a hollow cylindrical float is arranged in the tank body, a 90° elbow is arranged in the upper part of the float, an inlet of the elbow is arranged on the side of the float, and an outlet of the elbow is arranged on the other end of the elbow, the lower part of the float is a hollow container separated from the elbow, an annular cylinder is arranged outside the opening of the upper part of the elbow, an annular bottom plate is arranged between the upper part of the elbow and the float, a flue gas outlet pipeline is connected with the flue gas outlet, the other end of the flue gas outlet pipeline extends into the float, the outlet of the elbow extends into the flue gas outlet pipeline, the upper part of the elbow, the annular cylinder, the bottom plate and the extending part in the flue gas outlet pipeline form a zigzag annular channel, the zigzag annular channel is a water seal groove, the water seal inlet is connected with the water seal groove, and the water seal groove is filled with water to form a water seal; the sealing water in the water seal groove is connected with working water in the tank body through a siphon pipe, a siphon water inlet and a valve are arranged on the siphon pipe, and the float moves up and down in the tank body by increasing and reducing the sealing water in the water seal groove.

[0006] Further technical features of the application are that the annular bottom plate at the lower part of the zigzag annular channel is welded with the outer wall of the elbow and the inner wall of the upper part of the float respectively, and the water seal is formed after being filled with water.

[0007] Further technical features of the application are that the float is preferably a metal float.

[0008] Further technical features of the application are that the bending radius of the 90° elbow is 0.5-2.5 times of the flow diameter of the elbow, and the bending radius of the elbow is preferably 1 times of the flow diameter of the elbow plus 100 mm, and preferably 1 times of the flow diameter of the elbow.

[0009] Further technical features of the application are that the center of the outlet of the elbow is concentric with the center of the cross section of the float.

[0010] The water seal tank without pressure drop is mainly used on the pipeline of flue gas of a catalytic cracking device in the petroleum and chemical industry, and on the pipeline of flue gas of other devices similar to the process, such as an MTO (methanol to olefin) device, an HCC (heavy oil direct cracking to olefin) device and the like, and can also be applied to the flue gas pipeline cutting of other high-temperature flue gas energy recovery equipment with similar requirements.

[0011] Compared with existing technologies, the advantages of this invention are as follows: This invention provides a pressure-free water seal tank where the float utilizes the siphon principle and the buoyancy of water to drive the float to move up and down within the tank, thereby achieving the connection and offset between the two openings of the float bend and the two openings of the tank body. This eliminates the following resistances of the water seal tank: 1) abrupt changes in cross-section (sudden expansion or contraction); 2) flow around a cylinder; 3) gap flow; 4) 180° turns. Using this invention makes the water seal tank truly pressure-free, with an actual resistance of only about 14 Pa, thereby reducing the back pressure of the pipeline system by 500-800 Pa and achieving energy-saving goals for the flue gas system.

[0012] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this does not limit the scope of the invention. Attached Figure Description

[0013] Figure 1 is a schematic diagram of the structure of a pressureless dewatering sealing tank according to the present invention:

[0014] Figure 2 is a cross-sectional view of a non-pressure water seal tank float according to the present invention;

[0015] Figure 3 This is a schematic diagram of the working state of a pressure-free water seal tank according to the present invention (water seal tank in sealed state).

[0016] Figure 4 is a schematic diagram of the flue gas flow state of a pressureless water seal tank according to the present invention.

[0017] The attached figures are labeled as follows:

[0018] 1-Tank body; 2-Flue gas inlet; 3-Flue gas outlet; 4-Float; 41-Bottom cavity; 42-Elbow; 43-Annular cylinder; 44-Bottom plate; 45-Elbow inlet; 46-Elbow outlet; 5-Water seal inlet; 6-Tank body inlet and outlet; 7-Tank body water seal; 8-Working water; 9-Sealing water; 10-Siphon pipe; 11-Bottom valve; 12-Siphon water inlet. Detailed Implementation

[0019] like Figures 1-4 As shown, the present invention provides a pressureless water seal tank, which includes a cylindrical tank body 1, a flue gas outlet 3 at the top of the cylindrical tank body 1, and a water seal inlet 5 at the upper part or top of the tank body 1. Figures 1-4The water inlet 5 is arranged at the top of the tank 1, the middle side of the tank 1 is provided with the flue gas inlet 2, and the inside of the tank 1 is provided with a hollow cylindrical float 4. The upper part of the float 4 is provided with a 90° elbow 42, one end of the elbow 42 is provided with an elbow inlet 45 at the side of the float 4, the other end of the elbow 42 is an elbow outlet 46, and the lower part of the float 4 is a hollow container separated by the elbow 42, that is, a bottom cavity 41. An annular cylinder 43 is arranged outside the upper opening of the elbow 42, and an annular bottom plate 44 is arranged between the upper part of the elbow 42 and the float 4. The flue gas outlet 3 is connected with a flue gas outlet pipeline, the other end of the flue gas outlet pipeline extends into the float 4, the elbow outlet 46 extends into the flue gas outlet pipeline, the upper part of the elbow 42, the annular cylinder 43, the bottom plate 44 and the extended part of the flue gas outlet pipeline form a zigzag annular channel, the extended part of the flue gas outlet pipeline, that is, the part of the flue gas outlet pipeline extending into the float 4, can be called an extended cylinder 31, the zigzag annular channel is a water seal groove, the water inlet 5 is connected with the water seal groove, and the water seal groove forms a water seal after being filled with water. The sealing water 9 in the water seal groove is connected with the working water 8 in the tank 1 through a siphon pipe 10, the siphon pipe 10 is provided with a siphon water inlet 12 and a bottom valve 11, and the float 4 moves up and down in the tank 1 by increasing and reducing the sealing water 9 in the water seal groove.

[0020] When the float 4 composed of the elbow 42 and the hollow container is arranged at the lower part of the cylindrical tank 1, the elbow outlet 46 is inserted into the extended cylinder 31 of the flue gas outlet 3 of the tank 1, the elbow outlet 46 is connected with the flue gas outlet 3, and the elbow inlet 45 is connected with the flue gas inlet 2 of the tank 1.

[0021] As Figures 1-4 , the water seal groove is composed of the outer wall of the elbow 42, the cylindrical annular barrel 43 and the extended part of the pipeline of the flue gas outlet 3, that is, the extended cylinder 31.

[0022] The annular bottom plate at the lower part of the zigzag annular channel is welded with the outer wall of the elbow and the inner wall of the upper part of the float respectively, and forms a water seal after being filled with water.

[0023] The float is preferably a metal float.

[0024] The requirement for the elbow 42 is that the bending radius is as large as possible, but too large bending radius will make the size of the equipment too large, and in general cases, the bending radius of the elbow 42 is 0.5-2.5 times the flow diameter of the elbow 42. It is recommended that the bending radius of the elbow 42 is 1 times the flow diameter of the elbow 42 plus 100 mm, and preferably 1 times the flow diameter of the elbow 42.

[0025] The diameter of the elbow outlet 46 is smaller than the inner diameter of the flue gas outlet 3, so as to ensure that the elbow outlet 46 can freely move up and down in the pipeline of the flue gas outlet 3.

[0026] The water seal tank body 1 is a cylinder with various process openings sealed at upper and lower ends, and the water seal tank inner float 4 is a cylinder with upper and lower ends sealed and a 90° elbow 42 penetrating the middle and upper part, and the center of the elbow 42 upper end outlet is concentric with the center of the float cross section.

[0027] The application realizes pressure-free docking with the pipeline and guarantees the gas seal in working state by the movable part float 4.

[0028] The diameter of the elbow inlet 45 can be slightly larger than the inner diameter of the flue gas inlet 2, and is recommended to be 50-100 mm larger than the inner diameter of the flue gas inlet 2. The diameter of the elbow outlet 46 is 50-100 mm smaller than the inner diameter of the flue gas outlet 3.

[0029] The height H of the elbow 42 extending out of the bottom plate 44 is 200-3000 mm, and the specific value is determined according to the pressure drop of the subsequent process of the tank body.

[0030] The annular cylinder 43 can be provided with an overflow port, and the height h of the annular cylinder 43 is 200-300 mm, which can meet the requirements, and should not be too high to avoid too much water storage.

[0031] The water seal inner cavity formed by the ring barrel 43, the bottom plate 44 and the elbow 42 is connected with the tank body 1 through the siphon 10, so that the water in the annular water seal can be discharged into the tank body 1 through the siphon phenomenon. A simple check valve similar to the water pump bottom valve can be arranged at the outlet end of the siphon 10 in the annular water seal. The valve allows water to be sucked into the siphon 10 but cannot flow from the siphon 10 into the water seal. The distance h1 between the port of the siphon 10 and the bottom plate 44 of the annular water seal is 50-200 mm, so as to discharge the sealing water 9 as much as possible. The valve 11 and the siphon water inlet 12 are arranged on the siphon 10, which are used to form the initial conditions for the operation of the siphon 10. The water discharged from the siphon 10 can enter the tank body 1 or be discharged into the wastewater system outside the tank body 1.

[0032] The application has two operating states:

[0033] 1) flue gas flow state, see Figure 4 The operation process is as follows: close the upper bottom valve 11 of the siphon, fill the siphon 10 with water through the siphon water inlet 12, cut off the water filling after the siphon 10 is filled with water, then open the bottom valve 11, and the sealing water 9 is discharged through the siphon 10 or enters the tank body 1, the weight of the float 4 becomes smaller, and the float 4 floats upward until the inlet of the elbow 42 is opposite to the flue gas inlet 2 of the tank body 1, at which time the flue gas forms a passage through the elbow 42 of the water seal tank inner float 4;

[0034] 2) flue gas cutting state sealed by the water seal tank, see Figure 3The water inlet 5 is filled with water to fill the annular water seal, the buoy 4 is lowered due to its weight being greater than the buoyancy, and is lowered to the air inlet upper end of the buoy 4, and the submergence size h2 is 100-500 mm, at this time, the two ends of the buoy 4 are completely sealed by water.

[0035] In order to make the smoke inlet 2 and the elbow 42 inlet 45 more closely connected, the pipe of the smoke inlet 1 can be extended into the tank 1, so that the elbow inlet 45 of the elbow 42 and the smoke inlet 2 of the tank 1 form a good flow matching during operation. The water inlet 5 is arranged at the upper part of the tank 1, and the position of the water inlet should be such that the water falls into the cylindrical annular cylinder 43. The present application does not make specific provisions for the sizes of the parts and their matching, and these data are determined according to the smoke operation parameters and the diameters of the smoke outlet 3 and the smoke inlet 2; the weight of the buoy 4 and the volume of the cavity are determined according to the equipment size and the position of the buoy 4 during operation and shutdown; the positioning method of the buoy 4 is a commonly used method in engineering, and the present application does not make any requirements. The water seal 7 of the tank 1, the water inlet and outlet of the tank 6, etc. are not required, and the dashed lines in the figure represent the working water 8 and the sealing water 9.

[0036] In order to ensure the smooth operation of the tank, other structural details are as follows: the buoy 4 has sufficient volume to generate sufficient buoyancy to make the part 4 float in water; the water inlet and outlet 6 of the tank 1 is open, and the tank 1 is provided with a tank water seal 7; the axis of the buoy 4 is vertical and stable during movement, whether a guide rail is provided and how to provide the guide rail, how to handle the internal gas expansion of the cavity 41 when it is heated as a sealed cavity (one of the commonly used methods is to open several small holes at the upper part); the shape of the bottom of the cavity 41 and how to ensure that the bottom is not adhered to the bottom of the tank 1, etc. These structural details have corresponding conventional measures to achieve, and the present application does not make any provisions for these, but these details do not affect the scope of the present application.

[0037] The outer size of the buoy 4 is recommended to be close to the diameter of the tank 1 to reduce water consumption; in addition, the outer size of the buoy 4 can be of different diameters according to the buoyancy, gravity and floating distance, that is, a variable diameter design is adopted.

[0038] The present application only lists the main parts of the device, and other auxiliary accessories for the normal operation of the tank are not required by the device, and these do not affect the scope of the present application.

Claims

1. A pressureless dewatering sealing tank, characterized in that: The pressure-free water seal tank includes a cylindrical tank with a flue gas outlet at the top and a water seal inlet at the top or middle. A flue gas inlet is located on the side of the middle section of the tank. Inside the tank is a hollow cylindrical pontoon. A 90° elbow is inserted through the upper part of the pontoon, with an inlet at one end and an outlet at the other. The lower part of the pontoon is a hollow container separated from the elbow. An annular cylinder is located outside the upper opening of the elbow. An annular bottom plate is located between the upper part of the elbow and the pontoon. The flue gas outlet connects to a flue gas outlet pipe, with the other end of the pipe extending into the pontoon. The elbow outlet extends into the flue gas outlet pipe. The upper part, the annular cylinder, the bottom plate, and the inner extension of the flue gas outlet pipe form a sawtooth annular channel. The sawtooth annular channel is a water seal groove. The water seal inlet is connected to the water seal groove. After the water seal groove is filled with water, a water seal is formed. The sealing water in the water seal groove is connected to the working water in the tank through a siphon pipe. The increase and decrease of the sealing water in the water seal groove causes the float to move up and down in the tank. The float floats up until the inlet of the bend is directly opposite the flue gas inlet of the tank. At this time, the flue gas forms a passage through the bend of the float in the water seal tank, and the flue gas is in a flow state. The float descends until it is submerged underwater at the upper edge of the float's air inlet. At this time, both ends of the cylinder are completely sealed by water, and the flue gas is cut off and sealed by the water seal tank.

2. The pressureless dewatering sealing tank according to claim 1, characterized in that: The annular bottom plate at the lower part of the serrated annular channel is welded to the outer wall of the elbow and the upper inner wall of the pontoon, forming a water seal after being filled with water.

3. The pressureless dewatering sealing tank according to claim 1, characterized in that: The pontoon is a metal pontoon.

4. The pressureless dewatering sealing tank according to claim 1, characterized in that: The bending radius of the 90° elbow is 0.5 to 2.5 times the flow diameter of the elbow.

5. A pressureless dewatering sealing tank according to claim 1, characterized in that: The center of the elbow outlet is concentric with the center of the pontoon cross-section.

6. The pressureless dewatering sealing tank according to claim 1, characterized in that: The diameter of the elbow outlet is 50-100 mm smaller than the inner diameter of the flue gas outlet; the diameter of the elbow inlet is 50-100 mm larger than the inner diameter of the flue gas inlet.

7. A pressureless dewatering sealing tank according to claim 1, characterized in that: The height H of the elbow extending outward from the base plate is between 200mm and 3000mm.

8. A pressureless dewatering sealing tank according to claim 1, characterized in that: The height h of the annular cylinder can be set to 200-300 mm to meet the requirements.

9. A pressureless dewatering sealing tank according to claim 1, characterized in that: The siphon pipe has a bottom valve installed at its outlet end within the annular water seal, and the distance h1 between the port of the siphon pipe and the annular bottom plate is 50-200 mm.

10. A pressureless dewatering sealing tank according to claim 1, characterized in that: Water is filled into the water seal tank through the water seal inlet. The weight of the float is greater than the buoyancy and it descends until the upper edge of the float's elbow inlet is submerged in the tank and the underwater working dimension h2 is 100-500mm. At this point, both ends of the float are completely sealed by water.

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