Porous ceramic membrane tube mounting method for high-temperature and high-pressure filtering system

Abstract

The invention discloses a porous ceramic membrane tube mounting method for a high-temperature and high-pressure filtering system, and belongs to the field of porous ceramic membrane preparation and application. According to the method, a straight pipe type porous membrane pipe is mainly adopted to replace a traditional flange type porous ceramic membrane pipe structure, a traditional candle hanging type and pressing plate sealing mode is changed, and the fracture risk of the porous ceramic membrane pipe under a high-temperature and high-pressure filtering system is greatly reduced. The porous ceramic membrane tube is supported by the metal pull rod in the middle of the tube plate, the elastic sealing gaskets are adopted at the upper and lower bottoms of the metal pull rod for stress buffering, and the upper and lower elastic shaking allowance is increased at the bottom of the porous ceramic membrane tube in a spring fastening mode; the problem of rigid fracture of the porous ceramic membrane tube caused by stress concentration in a high-temperature and high-pressure environment is effectively solved, and the method can prolong the service life of the porous ceramic membrane tube in a high-temperature and high-pressure system.

Description

Technical Field

[0001] The invention relates to a porous ceramic membrane tube installation method for a high-temperature and high-pressure filtration system, and belongs to the field of porous ceramic membrane preparation and application. Background Art

[0002] Gas-solid separation is an important chemical unit operation. It is an indispensable link in the production process with gas-solid two-phase. It has important and extensive applications in coal-fired power plants, petrochemicals, steel metallurgy, coal chemical industry, food and medicine, new energy and new materials. There are many methods for gas-solid separation, the most common of which include gravity sedimentation, centrifugal separation, filtration and electrostatic precipitator. In recent years, researchers have successfully applied membrane separation technology from the field of water treatment to the field of gas-solid separation, achieving ultra-low emission control of PM2.5 dust. Gas-solid separation membranes are mainly divided into medium and low temperature membranes and high temperature membranes. Medium and low temperature membranes are mainly PTFE organic membrane materials, and the application temperature is lower than 260°C; while high temperature membranes are mainly inorganic materials, divided into porous ceramic membranes and porous metal membranes, and the application temperature is higher than 300°C. Porous ceramic membranes have certain advantages in separation and filtration performance under high temperature and high pressure corrosion environments.

[0003] The principle of high-temperature gas-solid separation membrane filtration is to remove large and small particles through surface membrane filtration, and then remove the dust on the surface through instantaneous reverse blowing of high-pressure gas. There is a big difference in the sealing method between the porous ceramic membrane and the porous metal membrane. The porous metal membrane is generally directly welded to the tube sheet or processed into a threaded connection method, which is relatively convenient, and under normal circumstances, it is not easy to break and be damaged by vibration. Although the porous ceramic membrane has excellent high temperature resistance and corrosion resistance, the ceramic itself has the characteristics of brittleness and low toughness, and cannot be threaded like metal. At present, the porous ceramic membrane used for high-temperature gas-solid separation is made into a hanging candle configuration (flange type). The membrane tube is suspended on the tube sheet, the bottom is fixed by a metal hanger, and the top is pressed with a pressure plate ( Figure 1 ). However, the weight and high-temperature thermal stress of the membrane tube in this installation method are concentrated in the flange part. In the high-temperature and high-pressure environment, and during the frequent cleaning process of high-pressure backflushing (>1.0MPa), the fatigue resistance of the membrane tube is greatly reduced, and it is easy to break, affecting the normal industrial production process. Therefore, changing the traditional installation and sealing method of high-temperature porous ceramic membrane tubes and reducing the risk of membrane tube breakage caused by thermal stress and backflushing vibration in high-temperature and high-pressure environments is of great significance to expanding the high-temperature application scenarios of porous ceramic membranes and improving the level of high-temperature gas-solid separation equipment. Summary of the invention

[0004] The technical problem that the present invention aims to solve is to provide a porous ceramic membrane tube installation method for high-temperature and high-pressure filtration systems in view of the deficiencies in the existing porous ceramic membrane installation and sealing technology for high-temperature and high-pressure applications. The method changes. The method mainly adopts a straight-tube porous ceramic membrane tube to replace the traditional flange-type porous ceramic membrane tube configuration, changes the traditional hanging candle type and pressure plate sealing method, and supports the porous ceramic membrane tube by using a metal tie rod in the middle of the tube plate. Elastic sealing pads are used at the upper and lower bottoms of the metal tie rod as stress buffers. The bottom of the porous ceramic membrane tube is tightened with a spring to increase the upper and lower elastic swing margins, which effectively solves the problem of rigid fracture of the porous ceramic membrane tube caused by stress concentration under high-temperature and high-pressure environments. This method can extend the service life of the porous ceramic membrane tube in high-temperature and high-pressure systems.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: A method for installing a porous ceramic membrane tube for a high-temperature and high-pressure filtration system, wherein the method uses a porous ceramic membrane tube as a filtration element, the porous ceramic membrane tube is installed and fixed by an intermediate metal tie rod, the metal tie rod is installed and suspended on a fixed bracket, and the fixed bracket is fixed to a tube sheet by fixing bolts and a fixed bracket sealing gasket; the upper and lower ends of the porous ceramic membrane tube are fixed by the tube sheet and a support plate, the top is close to the tube sheet, a support plate is provided at the bottom, a spring is provided under the support plate, a metal gasket is installed under the spring, and then fastened by a unidirectional nut; air holes are punched on the surface of the metal tie rod, and high-pressure gas is blown into the intermediate metal tie rod during the filtration process, and reverse high-pressure airflow is used to achieve online dust cleaning on the membrane tube surface.

[0006] The filter element is a single-channel straight tube type with an outer diameter of 40-70 mm, an inner diameter of 30-50 mm, and a length of 500-2000 mm.

[0007] The metal pull rod is hollow and porous on the surface. The diameter of the metal pull rod is 20-40 mm, the thickness is 3-5 mm, and the diameter of the pores on the surface of the metal pull rod is 5-8 mm.

[0008] The upper part of the metal pull rod is equipped with a venturi tube, the upper part of the venturi tube is directly facing the injection tube, and one metal pull rod is correspondingly equipped with one porous ceramic membrane tube.

[0009] The thickness of the tube sheet is 25-30 mm.

[0010] A groove and a sealing gasket are provided at the sealing position between the top of the porous ceramic tube and the tube plate. The groove depth is 8-12 mm, the groove diameter is 45-75 mm, the sealing gasket thickness is 5-8 mm, the sealing gasket outer diameter is 44-74 mm, and the sealing gasket inner diameter is 30-50 mm.

[0011] A support plate and an elastic sealing pad are provided at the bottom of the porous ceramic tube. The support plate has a depth of 12-17 mm, a diameter of 45-75 mm, a thickness of 3-5 mm, a thickness of 10-15 mm, an outer diameter of 42-72 mm, and an inner diameter of 20-40 mm.

[0012] The high-pressure gas backflush pressure is 0.2-4.0 MPa, and the backflush medium is air, nitrogen or argon.

[0013] The single-channel straight-tube porous ceramic tube is made of silicon carbide, alumina or mullite.

[0014] A venturi tube is arranged above the middle metal pull rod, and air holes are punched on the surface of the pull rod, with the diameter of the air holes being 5-8 mm.

[0015] A spring is arranged under the supporting plate, with a diameter of 30-40 mm, a free height of 30-50 mm, a helical angle of 5-10°, a pitch of 3-5 mm, and a steel wire diameter of 2-3 mm. Beneficial Effects

[0016] 1. The installation method of the present invention has a simple manufacturing process, good compatibility with similar products, convenient installation and disassembly, and is suitable for high-temperature gas-solid separation applications in large-scale industrial production.

[0017] 2. The installation method of the present invention solves the problem of traditional membrane tube hanging candle suspension method. The design increases the elastic swing margin of the membrane tube, so that the stress generated by gravity, high temperature and high-pressure blowing is transferred from the membrane tube to the high-strength metal pull rod, avoiding brittle fracture of the membrane tube due to fatigue. It can be suitable for gas purification applications under various high-temperature and high-pressure complex working conditions in process industries.

[0018] 3. The installation method of the present invention overcomes the problem of unsatisfactory back-blowing cleaning effect in the prior art. By introducing the porous surface technology of the Venturi tube-type intermediate metal tie rod, the airflow is first concentrated and then evenly dispersed, avoiding insufficient bottom pressure and air volume due to the increase in the length of the membrane tube, and can comprehensively improve the back-blowing cleaning effect of various parts of the membrane tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Attached Figure 1 It is a schematic diagram of the installation method of the porous ceramic membrane tube of the present invention.

[0020] Attached Figure 2 It is a top view schematic diagram of the installation method of the porous ceramic membrane tube of the present invention.

[0021] Attached Figure 3 It is a bottom view schematic diagram of the installation method of the porous ceramic membrane tube of the present invention.

[0022] Description of reference numerals: 1—tube sheet; 2—upper sealing groove; 3—fixed bracket; 4—metal pull rod; 4-1—Venturi tube; 4-2—injection pipe; 5—fixed bolt; 6—fixed bracket sealing gasket; 7—membrane tube top sealing gasket; 8—porous ceramic membrane tube; 9—membrane tube bottom sealing gasket; 10—support plate; 11—spring; 12—metal gasket; 13—nut. DETAILED DESCRIPTION

[0023] The present invention will be further explained below in conjunction with the examples. The following examples are only used to illustrate the present invention, but are not intended to limit the scope of the present invention. Example 1

[0024] As shown in the attached figure, a method for installing a porous ceramic membrane tube for a high-temperature and high-pressure filtration system is provided. The method uses a porous ceramic membrane tube 8 as a filter element. The porous ceramic membrane tube 8 is installed and fixed by means of an intermediate metal tie rod 4. The metal tie rod 4 is installed and suspended on a fixed bracket 3. The fixed bracket 3 is fixed to the tube sheet 1 by means of a fixing bolt 5 and a fixed bracket sealing gasket 6. The upper and lower ends of the porous ceramic membrane tube 8 are fixed by means of the tube sheet 1 and a support plate 10. The top is close to the tube sheet 1. A support plate 10 is provided at the bottom. A spring 11 is provided under the support plate 10. A metal gasket 12 is provided under the spring 11, and then fastened by means of a unidirectional nut 13. The surface of the metal tie rod 4 is perforated with air holes. During the filtration process, high-pressure gas is blown into the intermediate metal tie rod 4, and the membrane tube surface is cleaned online by means of a reverse high-pressure airflow. The specific sealing installation method includes the following steps: Step 1: First, fix the metal tie rod 4 with a diameter of 20 mm and a thickness of 3 mm on the fixed bracket 3. The fixed bracket 3 is fixed to the tube sheet 1 with a thickness of 25 mm by bolt fastening 5. The fixed bracket 3 and the tube sheet 1 are sealed with a metal graphite gasket 6.

[0025] Step 2. Then, insert the sealing gasket 7 on the top of the porous ceramic membrane tube 8 from the bottom of the metal pull rod 4. The sealing gasket model has a thickness of 5 mm, an outer diameter of 44 mm, and an inner diameter of 30 mm. Then, insert a porous ceramic membrane tube 8 made of alumina along the metal pull rod 4 until it enters the sealing groove 2 on the tube plate 1. The dimensions of the porous ceramic membrane tube 8 are an outer diameter of 40 mm, an inner diameter of 30 mm, and a length of 500 mm.

[0026] Step 3. Finally, put the membrane tube bottom sealing pad 9 with a thickness of 10 mm, an outer diameter of 42 mm, and an inner diameter of 20 mm into the bottom support plate 10, and insert it from the bottom of the metal pull rod 4 to ensure that the porous ceramic membrane tube 8 is just placed in the support plate, and then install the spring 11 and the metal gasket 12 in sequence. The spring specifications are 30 mm in diameter, 30 mm in free height, 5° helical angle, 3 mm pitch, and 2 mm steel wire diameter. Finally, tighten the membrane tube with the nut 13 until it cannot shake.

[0027] This implementation is mainly aimed at high-temperature and high-pressure intermittent filtration applications, which do not require online cleaning, with an application temperature of 300-800°C, a pressure of 0.1-1.0 MPa, and a service life of not less than 3 years. Example 2

[0028] Based on the installation method of Example 1, this embodiment adopts a straight tube silicon carbide porous ceramic membrane 8 with an outer diameter of 60 mm, an inner diameter of 40 mm, and a length of 1500 mm as a filter element. The porous ceramic membrane tube 8 is installed and fixed by an intermediate metal tie rod 4. The metal tie rod 4 is installed and suspended on a fixed bracket 3, and the fixed bracket 3 is fixed to the tube sheet 1 by fixing bolts 5 and a fixed bracket sealing gasket 6; the upper and lower ends of the porous ceramic membrane tube 8 are fixed by the tube sheet 1 and a support plate 10, the top is close to the tube sheet 1, and a support plate 10 is provided at the bottom. A spring 11 is provided under the support plate 10, and a metal gasket 12 is installed under the spring 11, which is then tightened by a unidirectional nut 13; the surface of the metal tie rod 4 is perforated with air holes, and high-pressure gas is blown into the intermediate metal tie rod 4 during the filtration process, and the membrane tube surface is cleaned online by reverse high-pressure airflow.

[0029] The specific sealing installation method includes the following steps: Step 1: First, fix the metal tie rod 4 with a diameter of 30 mm and a thickness of 4 mm and a venturi tube 4-1 on the fixed bracket 3. The fixed bracket 3 is fastened 5 to the tube sheet 1 with a thickness of 28 mm by bolts. The fixed bracket 3 and the tube sheet 1 are sealed with a metal graphite gasket 6. The surface of the metal tie rod 4 is punched with air holes with a diameter of 5 mm.

[0030] Step 2: Then, insert the top sealing gasket 7 of the porous ceramic membrane tube 8 from the bottom of the metal tie rod 4. The sealing gasket model has a thickness of 6 mm, an outer diameter of 64 mm, and an inner diameter of 40 mm. Then insert a silicon carbide porous ceramic membrane tube 8 along the metal tie rod 4 until the sealing gasket enters the sealing groove 2 on the tube sheet 1. The dimensions of the porous ceramic membrane tube 8 are an outer diameter of 60 mm, an inner diameter of 40 mm, and a length of 1500 mm.

[0031] Step 3. Then, put the membrane tube bottom sealing gasket 9 with a thickness of 12 mm, an outer diameter of 62 mm, and an inner diameter of 30 mm into the bottom support plate 10, and insert it from the bottom of the metal pull rod 4 to ensure that the porous ceramic membrane tube is just placed in the support plate, and then install the spring 11 and the metal gasket 12 in sequence. The spring specifications are 35 mm in diameter, 40 mm in free height, 8° in helix angle, 4 mm in pitch, and 2.5 mm in steel wire diameter. Finally, tighten it with the nut 13 until the membrane tube cannot shake.

[0032] Step 4. Finally, install the blowing tube 4-2 just above the porous ceramic membrane tube 8, so that the blowing port of the blowing tube faces the center of the metal pull rod 4, and introduce nitrogen gas at a pressure of 0.6 MPa.

[0033] This implementation is mainly aimed at high-temperature and high-pressure continuous filtration applications to achieve online pulse cleaning. The metal pull rod with air holes has better blowing effect and more uniform air flow distribution. The application temperature is 400-900℃, the pressure is 1.0-2.5 MPa, and the service life is not less than 4 years. Example 3

[0034] Based on the installation method of Example 2, this embodiment adopts a straight tube silicon carbide porous ceramic membrane 8 with an outer diameter of 70 mm, an inner diameter of 50 mm, and a length of 2000 mm as a filter element. The porous ceramic membrane tube 8 is installed and fixed by an intermediate metal tie rod 4. The metal tie rod 4 is installed and suspended on a fixed bracket 3, and the fixed bracket 3 is fixed to the tube sheet 1 by fixing bolts 5 and a fixed bracket sealing gasket 6; the upper and lower ends of the porous ceramic membrane tube 8 are fixed by the tube sheet 1 and a support plate 10, the top is close to the tube sheet 1, and a support plate 10 is provided at the bottom. A spring 11 is provided under the support plate 10, and a metal gasket 12 is installed under the spring 11, which is then tightened by a unidirectional nut 13; the surface of the metal tie rod 4 is perforated with air holes, and high-pressure gas is blown into the intermediate metal tie rod 4 during the filtration process, and the membrane tube surface is cleaned online by reverse high-pressure airflow.

[0035] The specific sealing installation method includes the following steps: Step 1: First, fix the metal tie rod 4 with a diameter of 40 mm and a thickness of 5 mm and a venturi tube 4-1 on the fixed bracket 3. The fixed bracket 3 is fastened 5 to the tube sheet 1 with a thickness of 30 mm by bolts. The fixed bracket 3 and the tube sheet 1 are sealed with a metal graphite gasket 6. The surface of the metal tie rod 4 is punched with air holes with a diameter of 8 mm.

[0036] Step 2: Then, insert the top sealing gasket 7 of the porous ceramic membrane tube 8 from the bottom of the metal tie rod 4. The sealing gasket model is 8 mm thick, 74 mm in outer diameter, and 50 mm in inner diameter. Then insert a silicon carbide porous ceramic membrane tube 8 along the metal tie rod 4 until the sealing gasket enters the sealing groove 2 on the tube sheet 1. The dimensions of the porous ceramic membrane tube 8 are 70 mm in outer diameter, 50 mm in inner diameter, and 2000 mm in length.

[0037] Step 3. Then, put the membrane tube bottom sealing gasket 9 with a thickness of 15 mm, an outer diameter of 72 mm, and an inner diameter of 40 mm into the bottom support plate 10, and insert it from the bottom of the metal pull rod 4 to ensure that the porous ceramic membrane tube is just placed in the support plate, and then install the spring 11 and the metal gasket 12 in sequence. The spring specifications are 40 mm in diameter, 50 mm in free height, 10° helical angle, 5 mm pitch, and 3 mm in steel wire diameter. Finally, tighten it with the nut 13 until the membrane tube cannot shake.

[0038] Step 4. Finally, install the blowing tube 4-2 just above the porous ceramic membrane tube 8, so that the blowing port of the blowing tube faces the center of the metal pull rod 4, and introduce nitrogen gas at a pressure of 4.0 MPa.

[0039] This implementation is mainly aimed at high-temperature and ultra-high-pressure continuous filtration applications to achieve online pulse cleaning. The metal pull rod with large-aperture air holes has better blowing effect and more uniform air flow distribution. The application temperature is 500-900℃, the pressure is 2.5-3.5 MPa, and the service life is not less than 5 years.

Claims

1. A method for installing a porous ceramic membrane tube for a high temperature and high pressure filtration system, characterized in that: The method uses a porous ceramic membrane tube (8) as a filtering element. The porous ceramic membrane tube (8) is installed and fixed by means of an intermediate metal tie rod (4). The metal tie rod (4) is installed and suspended on a fixed bracket (3). The fixed bracket (3) is fixed to a tube sheet (1) by means of a fixing bolt (5) and a fixing bracket sealing gasket (6). The upper and lower ends of the porous ceramic membrane tube (8) are fixed by means of a tube sheet (1) and a support plate (10). The top is tightly attached to the tube sheet (1). A support plate (10) is provided at the bottom. A spring (11) is provided under the support plate (10). A metal gasket (12) is provided under the spring (11) and is then tightened by means of a unidirectional nut (13). The surface of the metal tie rod (4) is perforated with air holes. During the filtering process, high-pressure gas is blown into the intermediate metal tie rod (4). The membrane tube surface is cleaned online by means of a reverse high-pressure airflow.

2. The method for installing a porous ceramic membrane tube for a high temperature and high pressure filtration system according to claim 1, characterized in that: The porous ceramic membrane tube (8) is a single-channel straight tube with an outer diameter of 40-70 mm, an inner diameter of 30-50 mm, and a length of 500-2000 mm.

3. The method for installing a porous ceramic membrane tube for a high temperature and high pressure filtration system according to claim 1, characterized in that: The metal pull rod (4) is hollow and has a porous surface. The metal pull rod (4) has a diameter of 20-40 mm and a thickness of 3-5 mm. The diameter of the pores on the surface of the metal pull rod (4) is 5-8 mm. A venturi tube (4-1) is installed on the upper part of the metal pull rod (4). The upper part of the venturi tube (4-1) faces the injection tube (4-2). One metal pull rod (4) is correspondingly installed with one porous ceramic membrane tube (8).

4. The method for installing a porous ceramic membrane tube for a high temperature and high pressure filtration system according to claim 1, characterized in that: The tube sheet (1) has a thickness of 25-30 mm.

5. The method for installing a porous ceramic membrane tube for a high temperature and high pressure filtration system according to claim 1, characterized in that: The top of the porous ceramic membrane tube (8) is sealed with the tube sheet (1) at a position where an upper sealing groove (2) and a membrane tube top sealing gasket (7) are provided; the upper sealing groove (2) has a depth of 8-12 mm and a diameter of 45-75 mm; the membrane tube top sealing gasket (7) has a thickness of 5-8 mm, an outer diameter of 44-74 mm, and an inner diameter of 30-50 mm.

6. The method for installing a porous ceramic membrane tube for a high temperature and high pressure filtration system according to claim 1, characterized in that: A membrane tube bottom sealing gasket (9) is installed between the bottom of the porous ceramic membrane tube (8) and the support plate (10); the support plate (10) has a depth of 12-17 mm, a diameter of 45-75 mm, and a thickness of 3-5 mm; the membrane tube bottom sealing gasket (9) has a thickness of 10-15 mm, an outer diameter of 42-72 mm, and an inner diameter of 20-40 mm.

7. The method for installing a porous ceramic membrane tube for a high temperature and high pressure filtration system according to claim 1, characterized in that: The high-pressure gas backflush pressure is 0.2-0.6 MPa, and the backflush medium is air, nitrogen or argon.

8. The method for installing a porous ceramic membrane tube for a high temperature and high pressure filtration system according to claim 1, characterized in that: The porous ceramic membrane tube (8) is made of silicon carbide, alumina or mullite.

9. The method for installing a porous ceramic membrane tube for a high temperature and high pressure filtration system according to claim 1, characterized in that: The spring (11) has a diameter of 30-40 mm, a free height of 30-50 mm, a helical angle of 5-10°, a pitch of 3-5 mm, and a steel wire diameter of 2-3 mm.

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