Anti-scaling air pre-heater heat storage element suitable for high-sulfur flue gas and design method

Abstract

The invention belongs to the technical field of air pre-heater heat storage elements, and particularly relates to an anti-scaling air pre-heater heat storage element suitable for high-sulfur flue gas and a design method.The anti-scaling air pre-heater heat storage element comprises a first square plate and corrugated plates, a plurality of supporting rods are fixedly installed on one side of the first square plate, and the ends of the supporting rods penetrate through the corrugated plates and are fixed through pressing assemblies; a nano ceramic coating is arranged on the surface of the corrugated plate, so that the surface characteristics of the corrugated plate can be optimized. A plurality of second micropores are formed in the corrugated plate, and first micropores are formed in the nano ceramic coating on the two sides of the second micropores. The nano ceramic coating is arranged on the surface of the corrugated plate, and the micropores capable of causing the corrugated plate to vibrate are formed in the corrugated plate, so that when the air pre-heater heat storage element is applied to high-sulfur flue gas, the attachment amount of fly ash and ammonium bisulfate can be reduced, and the anti-scaling performance of the air pre-heater heat storage element is improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of air preheater heat storage elements, in particular to an anti-fouling air preheater heat storage element suitable for high-sulfur flue gas and a design method. BACKGROUND

[0002] The air preheater heat storage element is a core component of an air preheater, and is mainly used for storing and transferring heat to preheat combustion air and improve the efficiency of a thermal system. The air preheater heat storage element suitable for high-sulfur flue gas is a special heat exchange component developed for a harsh environment with high sulfur content (such as sulfur content > 2%) and sulfur trioxide concentration > 20 ppm.

[0003] However, the air preheater heat storage element suitable for high-sulfur flue gas may be fouled due to fly ash adhesion and ammonium bisulfate deposition on the surface during long-time operation, thereby affecting the subsequent use of the air preheater heat storage element. Therefore, the application provides an anti-fouling air preheater heat storage element suitable for high-sulfur flue gas and a design method. SUMMARY

[0004] To solve the above technical problems, according to one aspect of the application, the application provides the following technical scheme:

[0005] The anti-fouling air preheater heat storage element suitable for high-sulfur flue gas comprises a first square plate and a corrugated plate, a plurality of support rods are fixedly installed on one side of the first square plate, the end portions of the support rods pass through a plurality of corrugated plates and are fixed by a pressing assembly, and the surface of the corrugated plate is provided with a nano ceramic coating to optimize the surface properties of the corrugated plate.

[0006] As a preferred scheme of the anti-fouling air preheater heat storage element suitable for high-sulfur flue gas, a plurality of second micropores are formed in the corrugated plate, a plurality of first micropores are formed in the nano ceramic coating on the two sides of the second micropores, and the first micropores are in communication with the second micropores.

[0007] As a preferred scheme of the anti-fouling air preheater heat storage element suitable for high-sulfur flue gas, the anti-fouling air preheater heat storage element further comprises:

[0008] A dredging assembly is arranged on the side of the nano ceramic coating to avoid blockage of the first micropores and the second micropores.

[0009] As a preferred scheme of the anti-fouling air preheater heat storage element suitable for high-sulfur flue gas, the dredging assembly comprises:

[0010] An elastic diaphragm is arranged on the outer side of the nano ceramic coating above the first micropores.

[0011] A top rod is fixedly installed on one side of the elastic diaphragm and penetrates the first micro-hole and the second micro-hole.

[0012] As a preferred scheme of the anti-fouling heat accumulator element of the air preheater suitable for high-sulfur flue gas, the pressing assembly comprises:

[0013] A second square plate, the end of the support rod penetrates the second square plate, and a plurality of corrugated plates are arranged between the second square plate and the first square plate;

[0014] A threaded hole is arranged in the cylindrical column, and the threaded rod is screwed into the threaded hole.

[0015] As a preferred scheme of the anti-fouling heat accumulator element of the air preheater suitable for high-sulfur flue gas, the pressing assembly further comprises:

[0016] A cylindrical column is in contact with the second square plate.

[0017] A threaded groove is arranged in the cylindrical column, and the threaded rod is screwed into the threaded groove.

[0018] As a preferred scheme of the anti-fouling heat accumulator element of the air preheater suitable for high-sulfur flue gas, the nano-ceramic coating is formed by spraying the nano-ceramic coating material, and the raw materials of the nano-ceramic coating material include, by weight, alpha alumina, yttrium-stabilized zirconia, silicon carbide, chromium sesquioxide, nickel-chromium alloy powder, calcium fluoride, nano-sized carbon fluoride particles, graphene, cerium dioxide, and spinel.

[0019] The design method of the anti-fouling heat accumulator element of the air preheater suitable for high-sulfur flue gas comprises the following specific steps:

[0020] S1: First, prepare the nano-ceramic coating material from alpha alumina, yttrium-stabilized zirconia, silicon carbide, chromium sesquioxide, nickel-chromium alloy powder, calcium fluoride, nano-sized carbon fluoride particles, graphene, cerium dioxide, and spinel.

[0021] S2: Spray the nano-ceramic coating material on the corrugated plate by using the plasma spraying technology, so as to form a nano-ceramic coating on the surface of the corrugated plate.

[0022] S3: Use a laser perforating machine to form a plurality of second micro-holes and first micro-holes on the corrugated plate and the nano-ceramic coating.

[0023] S4: Use the bonding technology to arrange the elastic diaphragm on one side of the first micro-hole.

[0024] S5: First, make the end of the support rod penetrate a plurality of corrugated plates, and then screw the cylindrical column to the threaded rod, so as to press and fix the corrugated plates.

[0025] As a preferred scheme of the design method of the anti-fouling heat accumulating element of the air preheater suitable for high-sulfur flue gas, the raw materials of the nano ceramic coating include, in parts by weight, 10-14 parts of alpha alumina, 6-10 parts of yttrium stabilized zirconia, 2-4 parts of silicon carbide, 3-5 parts of chromium sesquioxide, 1-5 parts of nickel-chromium alloy powder, 1-3 parts of calcium fluoride, 4-6 parts of nano-level carbon fluoride particles, 2-6 parts of graphene, 1-3 parts of cerium dioxide, and 1-3 parts of spinel.

[0026] As a preferred scheme of the design method of the anti-fouling heat accumulating element of the air preheater suitable for high-sulfur flue gas, the preparation steps of the nano ceramic coating are as follows:

[0027] Step one, mechanical mixing and ball milling:

[0028] First, the alpha alumina, yttrium stabilized zirconia, silicon carbide, chromium sesquioxide, cerium dioxide, and spinel are added to a planetary ball mill in the proportion, and the ball milling is performed for 8-12 hours under the zirconia balls in anhydrous ethanol as the medium to uniformly disperse and refine the nano particles; then, the nickel-chromium alloy powder is added, and the ball milling is continued for 2-4 hours to form a ceramic-metal composite powder; finally, the calcium fluoride, nano-level carbon fluoride particles, and graphene are added and mixed for 4-6 hours to avoid the destruction of the structure of the low-surface-energy particles by high shear force.

[0029] Step two, drying and granulation:

[0030] The slurry after the ball milling is dried in vacuum to remove the medium, and the obtained powder is granulated by a spray granulator to form spherical particles with a particle size of 50-100 μm to obtain the nano ceramic coating, wherein the temperature of the vacuum drying is set to 60-80℃, and the inlet air temperature of the spray granulator is set to 180-220℃, and the outlet air temperature is set to 80-100℃.

[0031] Compared with the prior art:

[0032] By setting the nano ceramic coating on the surface of the corrugated plate and the micropores capable of causing the vibration of the corrugated plate on the corrugated plate, the amount of the attached fly ash and ammonium bisulfate can be reduced when the heat accumulating element of the air preheater is applied to the high-sulfur flue gas, and the anti-fouling performance of the heat accumulating element of the air preheater is improved; in addition, by setting the dredging assembly, the micropores can be prevented from being blocked, and the service life of the micropores is prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a structural front view of the present application;

[0034] Figure 2 is a structural front view of the present application; Figure 1 is an enlarged schematic view of the structure at A in the present application;

[0035] Figure 3 It is the schematic diagram of corrugated plate structure of the present application;

[0036] Figure 4 It is the schematic diagram of sectional view of corrugated plate of the present application;

[0037] Figure 5 It is the schematic diagram of opening state of dredging assembly of the present application;

[0038] Figure 6 It is the schematic diagram of structure of dredging assembly of the present application.

[0039] In the figure: first square plate 10, support rod 20, corrugated plate 30, second square plate 40, stud 41, cylinder 42, threaded groove 43, nano ceramic coating 50, first micropore 51, second micropore 60, elastic diaphragm 61, top rod 62. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the present application more clear, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0041] The present application provides anti-fouling air preheater heat accumulating element suitable for high sulfur flue gas, please refer to Figures 1-6 , including first square plate 10 and corrugated plate 30, the first square plate 10 side fixedly installs a plurality of support rods 20, and the end of the support rod 20 passes through a plurality of corrugated plates 30 and is fixed by a compression assembly, the surface of the corrugated plate 30 is provided with a nano ceramic coating 50, so as to be able to optimize the surface properties of the corrugated plate 30;

[0042] The compression assembly comprises: second square plate 40, stud 41, cylinder 42, threaded groove 43;

[0043] The end of the support rod 20 passes through the second square plate 40, and a plurality of corrugated plates 30 are arranged between the second square plate 40 and the first square plate 10, the stud 41 is fixedly installed on the end of the support rod 20, the cylinder 42 is in contact with the second square plate 40, the threaded groove 43 is formed in the cylinder 42, and the stud 41 is screwed in the threaded groove 43.

[0044] When the end of the support rod 20 passes through a plurality of corrugated plates 30, then the end of the support rod 20 passes through the second square plate 40, then the stud 41 is screwed in the threaded groove 43, until the cylinder 42 is tightened, at this time, a plurality of corrugated plates 30 can be compressed and fixed.

[0045] The corrugated plate 30 is provided with a plurality of second micropores 60, the nanoceramic coating 50 on both sides of the second micropores 60 is provided with a first micropore 51, and the first micropore 51 is in communication with the second micropore 60; wherein when the flue gas passes through the first micropore 51 and the second micropore 60, the flue gas forms a high-speed jet at the micropores (the first micropore 51 and the second micropore 60), at this time the jet interacts with the surrounding air to cause airflow separation, thereby generating alternating vortexes behind the outlet, at this time the vortexes periodically fall off to exert a periodic force on the surrounding medium or the micropore structure, thereby causing vibration to shake off fly ash and ammonium bisulfate.

[0046] Further comprising: a dredging assembly for avoiding blockage of the first micropore 51 and the second micropore 60, and the dredging assembly is arranged on the side of the nanoceramic coating 50.

[0047] The dredging assembly comprises: an elastic diaphragm 61, a top rod 62;

[0048] The outer side of the nanoceramic coating 50 above the first micropore 51 is provided with an elastic diaphragm 61, the top rod 62 is fixedly installed on one side of the elastic diaphragm 61, and the top rod 62 passes through the first micropore 51 and the second micropore 60; wherein when the flue gas passes through the first micropore 51 and the second micropore 60, the elastic diaphragm 61 deforms, opens the micropores (the first micropore 51 and the second micropore 60), and if the flue gas does not pass through, the elastic diaphragm 61 returns to the original position and makes the top rod 62 pass through the micropores (the first micropore 51 and the second micropore 60), so as to be able to eject the impurities in the micropores (the first micropore 51 and the second micropore 60) and avoid blockage.

[0049] The nanoceramic coating 50 is formed by spraying nanoceramic coating material, and the raw materials of the nanoceramic coating material include, by weight: alpha alumina, yttrium stabilized zirconia, silicon carbide, chromium sesquioxide, nickel-chromium alloy powder, calcium fluoride, nanoscale carbon fluoride particles, graphene, cerium dioxide, and spinel.

[0050] Among them:

[0051] Regarding alpha alumina: high hardness (HV2000), strong chemical inertness, resistant to sulfuric acid mist corrosion, nanoscale powder (particle size 50-100 nm) sintered density > 98%, low surface energy (about 30 mN / m), reducing dust physical adhesion.

[0052] Regarding yttrium stabilized zirconia: excellent thermal shock resistance (thermal expansion coefficient close to metal), resistant to sulfide corrosion in high-temperature (400-600℃) high-sulfur flue gas, and inhibiting coating cracking caused by crystal type transformation.

[0053] About silicon carbide: better wear resistance than alumina, can reduce roughness and ash accumulation points on the coating surface due to wear in high-sulfur flue gas containing fly ash particles;

[0054] About chromium trioxide: strong acid resistance (corrosion rate <0.1 mm / year in 10% sulfuric acid solution), can inhibit the reaction of sulfur trioxide in flue gas with the coating to form sticky sulfate.

[0055] About nickel-chromium alloy powder: form a metallurgical bond by plasma spraying (bond strength > 70 MPa), and itself can form a chromium trioxide passivation film in a hydrogen sulfide-containing flue gas, preventing sulfur from penetrating into the matrix.

[0056] About calcium fluoride: reduce the surface energy of the coating to below 25 mN / m, so that the contact angle of liquid sulfuric acid droplets is >100°, forming beads and rolling off; at the same time, the melting point of calcium fluoride (1423°C) is higher than the flue gas temperature, and it will not decompose and fail at high temperature.

[0057] About nanoscale carbon fluoride particles: form a hydrophobic layer with a thickness of 50-100 nm, and the arrangement of nanoscale carbon fluoride segments can further reduce the surface energy to 20 mN / m.

[0058] About graphene: reduce the surface resistivity of the coating to 10 6 ~ 10 8 Ω·cm, eliminating the problem of dust adsorption due to static electricity.

[0059] About cerium dioxide: use the variable valence characteristics of rare earth elements to inhibit the catalytic oxidation of sulfur dioxide on the coating surface, reduce the generation of sticky products such as calcium sulfate, and refine the ceramic grains (particle size <100 nm) to improve surface smoothness.

[0060] About spinel: can resist the erosion of molten salt.

[0061] The design method of the anti-fouling heat accumulating element of the air preheater suitable for high-sulfur flue gas comprises the following specific steps:

[0062] S1: First, prepare a nanoceramic coating according to alpha alumina, yttrium-stabilized zirconia, silicon carbide, chromium trioxide, nickel-chromium alloy powder, calcium fluoride, nanoscale carbon fluoride particles, graphene, cerium dioxide, and spinel;

[0063] S2: Apply the nanoceramic coating to the corrugated plate 30 by plasma spraying technology to form a nanoceramic coating 50 on the surface of the corrugated plate 30;

[0064] S3: Use a laser perforating machine to open a plurality of second micro-holes 60 and first micro-holes 51 on the corrugated plate 30 and the nanoceramic coating 50;

[0065] S4: Use adhesive technology to place an elastic diaphragm 61 on one side of the first micro-holes 51;

[0066] S5: first make the end of the support rod 20 through several corrugated plates 30, then thread the cylinder 42 on the stud 41 to realize the compression fixing of the corrugated plate 30.

[0067] The raw materials of the nano ceramic coating include, in parts by weight, 10-14 parts of alpha alumina, 6-10 parts of yttrium stabilized zirconia, 2-4 parts of silicon carbide, 3-5 parts of chromium sesquioxide, 1-5 parts of nickel-chromium alloy powder, 1-3 parts of calcium fluoride, 4-6 parts of nano fluorocarbon particles, 2-6 parts of graphene, 1-3 parts of cerium dioxide and 1-3 parts of spinel.

[0068] The preparation steps of the nano ceramic coating are as follows:

[0069] Step one, mechanical mixing and ball milling:

[0070] First, the alpha alumina, yttrium stabilized zirconia, silicon carbide, chromium sesquioxide, cerium dioxide and spinel are added to the planetary ball mill according to the proportion, and the anhydrous ethanol is used as the medium to ball mill under the zirconia ball for 8-12 hours to make the nano particles uniformly dispersed and refined; then, the nickel-chromium alloy powder is added and the ball milling is continued for 2-4 hours to form a ceramic-metal composite powder; finally, the calcium fluoride, nano fluorocarbon particles and graphene are added and mixed for 4-6 hours to avoid the damage to the low surface energy particle structure caused by high shear force;

[0071] Step two, drying and granulation:

[0072] The slurry after ball milling is dried in vacuum to remove the medium, and the obtained powder is granulated by a spray granulator to form spherical particles with a particle size of 50-100 microns to obtain the nano ceramic coating, wherein the temperature of vacuum drying is set to 60-80 DEG C, and the inlet air temperature of the spray granulator is set to 180-220 DEG C and the outlet air temperature is set to 80-100 DEG C.

[0073] Although the present application has been described with reference to the embodiments above, various improvements can be made thereto and equivalents can be substituted therefor without departing from the scope of the present application. In particular, each of the features disclosed in the embodiments of the present application can be combined with each other by any means as long as there is no structural conflict, and the combinations of these features are not exhaustively described in the specification only for the purpose of omitting the length and saving resources. Therefore, the present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. Anti-fouling heat accumulating element of air preheater suitable for high sulfur flue gas, comprising first square plate (10) and corrugated plate (30), one side of the first square plate (10) is fixedly installed with a plurality of support rods (20), and the end of the support rod (20) penetrates through a plurality of corrugated plates (30) and is fixed by a compression assembly, characterized in that, The surface of the corrugated plate (30) is provided with a nano ceramic coating (50) to optimize the surface properties of the corrugated plate (30).

2. The anti-fouling heat storage element of the air preheater suitable for high sulfur flue gas as claimed in claim 1 wherein, The corrugated plate (30) is provided with a plurality of second micropores (60), the nano ceramic coating (50) on both sides of the second micropores (60) is provided with a first micropore (51), and the first micropore (51) is in communication with the second micropore (60).

3. The anti-fouling heat storage element of the air preheater suitable for high sulfur flue gas as claimed in claim 2 wherein, Also includes: A dredging assembly for preventing the first micropore (51) and the second micropore (60) from being blocked, and the dredging assembly is arranged on the side of the nano ceramic coating (50).

4. The anti-fouling heat storage element of the air preheater suitable for high sulfur flue gas as claimed in claim 3 wherein, The dredging assembly includes: An elastic diaphragm (61) is arranged on the outside of the nano ceramic coating (50) above the first micropore (51); A jacking rod (62) is fixedly installed on one side of the elastic diaphragm (61), and the jacking rod (62) penetrates the first micropore (51) and the second micropore (60).

5. The anti-fouling heat storage element of the air preheater suitable for high sulfur flue gas as claimed in claim 1 wherein, The pressing assembly includes: A second square plate (40) is arranged on the end of the support rod (20), and a plurality of corrugated plates (30) are arranged between the second square plate (40) and the first square plate (10); A stud (41) is fixedly installed on the end of the support rod (20).

6. The anti-fouling heat storage element of the air preheater suitable for high sulfur flue gas as claimed in claim 5 wherein, The pressing assembly further includes: A cylinder (42) is in contact with the second square plate (40); A threaded groove (43) is formed in the cylinder (42), and the stud (41) is threadedly connected in the threaded groove (43).

7. The anti-fouling heat storage element of the air preheater suitable for high sulfur flue gas as claimed in claim 1 wherein, The nano ceramic coating (50) is formed by spraying nano ceramic coating, and the raw materials of the nano ceramic coating include alpha alumina, yttrium stabilized zirconia, silicon carbide, chromium sesquioxide, nickel-chromium alloy powder, calcium fluoride, nano fluorocarbon particles, graphene, cerium dioxide, and spinel.

8. A method of designing anti-fouling heat storage elements for an air preheater suitable for high sulphur flue gas, characterised in that, The specific steps are as follows: S1: First, prepare the nano ceramic coating according to alpha alumina, yttrium stabilized zirconia, silicon carbide, chromium sesquioxide, nickel-chromium alloy powder, calcium fluoride, nano fluorocarbon particles, graphene, cerium dioxide, and spinel; S2: The nano ceramic coating is sprayed on the corrugated plate (30) by plasma spraying technology to form a nano ceramic coating (50) on the surface of the corrugated plate (30); S3: A laser drilling machine is used to form a plurality of second micropores (60) and first micropores (51) on the corrugated plate (30) and the nano ceramic coating (50); S4: An elastic diaphragm (61) is arranged on one side of the first micropore (51) by using adhesive technology; S5: First, the end of the support rod (20) penetrates a plurality of corrugated plates (30), and then the cylinder (42) is threadedly connected to the stud (41) to press and fix the corrugated plate (30).

9. A method of designing anti-fouling heat storage elements of an L.P. pre- heater suitable for high sulphur flue gas as claimed in claim 8 wherein, The raw materials of the nano ceramic coating include, in parts by weight, 10-14 parts of alpha alumina, 6-10 parts of yttrium stabilized zirconia, 2-4 parts of silicon carbide, 3-5 parts of chromium trioxide, 1-5 parts of nickel-chromium alloy powder, 1-3 parts of calcium fluoride, 4-6 parts of nano-sized carbon fluoride particles, 2-6 parts of graphene, 1-3 parts of cerium dioxide and 1-3 parts of spinel.

10. A method of designing fouling resistant heat storage elements of an air preheater suitable for high sulphur flue gas as claimed in claim 9 wherein, The preparation steps of the nano ceramic coating are as follows: Step one, mechanical mixing and ball milling: First, the alpha alumina, yttrium stabilized zirconia, silicon carbide, chromium trioxide, cerium dioxide and spinel are added to a planetary ball mill in the proportioning ratio, and anhydrous ethanol is used as the medium to ball mill for 8-12 hours under zirconia balls to uniformly disperse and refine the nano particles; then, the nickel-chromium alloy powder is added and ball milling is continued for 2-4 hours to form a ceramic-metal composite powder; finally, the calcium fluoride, nano-sized carbon fluoride particles and graphene are added and mixed for 4-6 hours to avoid the destruction of the structure of low surface energy particles by high shear force; Step two, drying and granulation: The slurry after ball milling is dried in vacuum to remove the medium, and the obtained powder is granulated by a spray granulator to form spherical particles with a particle size of 50-100 microns, thereby obtaining the nano ceramic coating, wherein the temperature of vacuum drying is set to 60-80 DEG C, and the inlet air temperature of the spray granulator is set to 180-220 DEG C and the outlet air temperature is set to 80-100 DEG C.

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