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CN-121248299-B - Silicon carbide ceramic heat exchange tube and preparation method thereof

CN121248299BCN 121248299 BCN121248299 BCN 121248299BCN-121248299-B

Abstract

The invention discloses a silicon carbide ceramic heat exchange tube and a preparation method thereof, and belongs to the technical field of silicon carbide ceramics. The preparation method of the silicon carbide ceramic heat exchange tube comprises the following steps of dispersing a modifier in absolute ethyl alcohol, adding silicon carbide fine powder for reaction to obtain modified silicon carbide fine powder, stirring phenolic resin, modified benzoxazine and absolute ethyl alcohol, sequentially adding carbon black, fly ash, modified silicon carbide fine powder and silicon carbide coarse powder, stirring and mixing uniformly, aging, pugging, extrusion molding and drying to obtain a silicon carbide blank, and placing the silicon carbide blank into a high-temperature furnace for heat treatment to obtain the silicon carbide ceramic heat exchange tube. The silicon carbide ceramic heat exchange tube prepared by the invention has excellent density, bending strength and fracture toughness.

Inventors

  • ZHANG WENJUN

Assignees

  • 江苏康大联合节能科技有限公司

Dates

Publication Date
20260512
Application Date
20251017

Claims (5)

  1. 1. The preparation method of the silicon carbide ceramic heat exchange tube is characterized by comprising the following steps of: (1) Dispersing the modifier in absolute ethyl alcohol, and adding silicon carbide fine powder for reaction to obtain modified silicon carbide fine powder; (2) Stirring phenolic resin, modified benzoxazine and absolute ethyl alcohol, sequentially adding carbon black, fly ash, modified silicon carbide fine powder and silicon carbide coarse powder, stirring, mixing uniformly, aging, pugging, extrusion molding and drying to obtain a silicon carbide biscuit; (3) Placing the silicon carbide biscuit into a high-temperature furnace for heat treatment to obtain a silicon carbide ceramic heat exchange tube; the modifier is prepared by the following method: S1, diphenyl silicon glycol reacts with 3-aminopropyl methyl dimethoxy silane to generate linear polysiloxane, S2, reacting linear polysiloxane with gamma-chloropropyl trimethoxysilane to generate a modifier; In the step S1, the feeding molar ratio of the diphenyl silicon glycol to the 3-aminopropyl methyl dimethoxy silane is (0.9-1) 1, and in the step S2, the feeding mass ratio of the linear polysiloxane to the gamma-chloropropyl trimethoxy silane is (2) (0.8-1); the modified benzoxazine is prepared by the following method: N1, reacting amine-terminated polyether with 3-chloro-1, 2-propanediol to generate dipropylene glycol modified polyether, N2 is that the dipropylene glycol modified polyether reacts with 4-aminophenylboric acid to generate borate modified polyether, Reacting borate modified polyether with phenol under the action of paraformaldehyde to generate modified benzoxazine; the structural formula of the modified benzoxazine is as follows: ; in the step N1, the feeding molar ratio of the amine-terminated polyether to the 3-chloro-1, 2-propanediol is 1:2.05, in the step N2, the feeding molar ratio of the dipropylene glycol modified polyether to the 4-aminophenylboric acid is 1:2.1, and in the step N3, the feeding molar ratio of the borate modified polyether to the phenol is 1:2.1.
  2. 2. The preparation method of the silicon carbide ceramic heat exchange tube according to claim 1 is characterized in that in the steps (1) to (2), the weight parts of the components are 25-35 parts of silicon carbide fine powder, 50-60 parts of silicon carbide coarse powder, 10-12 parts of carbon black, 4-5 parts of fly ash, 0.5-0.8 part of modifier, 8-10 parts of phenolic resin and 4-6 parts of modified benzoxazine.
  3. 3. The method for producing a silicon carbide ceramic heat exchange tube according to claim 1, wherein in the step (1), the mass ratio of the modifier to absolute ethyl alcohol is 1:200.
  4. 4. The method for preparing a silicon carbide ceramic heat exchange tube according to claim 1, wherein in the step (3), the heat treatment process is that the heat is preserved for 1-2h at 900-1100 ℃ and for 2-3h at 1600-1700 ℃.
  5. 5. A silicon carbide ceramic heat exchange tube produced by the method of any one of claims 1 to 4.

Description

Silicon carbide ceramic heat exchange tube and preparation method thereof Technical Field The invention relates to the technical field of silicon carbide ceramics, in particular to a silicon carbide ceramic heat exchange tube and a preparation method thereof. Background The ceramic heat exchanger can perform waste heat recovery and utilization, improves energy utilization efficiency, reduces energy consumption and pollution emission, and has wide application prospects in the fields of chemical industry, metallurgy, petroleum, electric power and the like. The silicon carbide ceramic has the advantages of high heat conductivity, high temperature resistance, corrosion resistance, wear resistance, good chemical stability and the like, and becomes an ideal choice for the heat exchanger material under extreme working conditions such as high temperature environment, strong acid and strong alkali corrosion, severe wear and the like. The defect of the performance of the silicon carbide ceramic material (such as poor bending strength, fracture toughness and the like) is one of important factors for restricting the preparation and popularization and application of the high-performance silicon carbide ceramic heat exchange tube. Because silicon carbide has extremely strong covalent bonds and extremely low diffusion coefficients, the difficulty of complete densification of silicon carbide ceramic is great, and the mechanical properties of the silicon carbide ceramic are affected. In addition, the phenolic resin generates shrinkage stress during crosslinking, which is easy to cause deformation and cracking of ceramic blanks and affects the performance of products. The Chinese patent with publication number CN114560702A discloses a pressureless sintering extrusion silicon carbide ceramic process, wherein the silicon carbide ceramic comprises silicon carbide, titanium diboride, carbon black, boron carbide, polyethylene glycol, corn starch, sodium carboxymethyl cellulose, epoxy resin, ethanolamine, a modified stabilizer, phytic acid, emulsified fatty acid and deionized water, the process comprises mixing, mud refining, ageing, extrusion molding, high-frequency electromagnetic oscillation treatment, drying and sintering, and the process has the advantages of small equipment investment, low energy consumption, low cost, simple process, high thermal conductivity, corrosion resistance, wear resistance and high temperature resistance of the prepared product, but the mechanical property of the prepared product is still insufficient. Disclosure of Invention Aiming at the defects existing in the prior art, the invention aims to provide a silicon carbide ceramic heat exchange tube and a preparation method thereof. In order to achieve the above object, the present invention is realized by the following technical scheme: a preparation method of a silicon carbide ceramic heat exchange tube comprises the following steps: (1) Dispersing the modifier in absolute ethyl alcohol, and adding silicon carbide fine powder for reaction to obtain modified silicon carbide fine powder; (2) Stirring phenolic resin, modified benzoxazine and absolute ethyl alcohol, sequentially adding carbon black, fly ash, modified silicon carbide fine powder and silicon carbide coarse powder, stirring, mixing uniformly, aging, pugging, extrusion molding and drying to obtain a silicon carbide biscuit; (3) Placing the silicon carbide biscuit into a high-temperature furnace for heat treatment to obtain a silicon carbide ceramic heat exchange tube; the modifier is prepared by the following method: S1, reacting diphenyl silicon glycol with 3-aminopropyl methyl dimethoxy silane to generate linear polysiloxane, wherein the reaction equation is shown as follows: 。 S2, reacting linear polysiloxane with gamma-chloropropyl trimethoxysilane to generate a modifier, wherein the reaction equation is shown as follows: 。 In the step S1, the feeding molar ratio of the diphenyl silicon glycol to the 3-aminopropyl methyl dimethoxy silane is (0.9-1) 1, and in the step S2, the feeding mass ratio of the linear polysiloxane to the gamma-chloropropyl trimethoxy silane is (0.8-1). The modified benzoxazine is prepared by the following method: n1 is that amine-terminated polyether reacts with 3-chloro-1, 2-propanediol to generate dipropylene glycol modified polyether, and the reaction equation is shown as follows: 。 n2 is that the dipropylene glycol modified polyether reacts with 4-aminophenylboric acid to generate borate modified polyether, and the reaction equation is shown as follows: 。 The reaction of borate modified polyether and phenol under the action of paraformaldehyde to produce modified benzoxazine has the reaction equation shown as follows: 。 in the step N1, the feeding molar ratio of the amine-terminated polyether to the 3-chloro-1, 2-propanediol is 1:2.05. In the step N2, the feeding molar ratio of the dipropylene glycol modified polyether to the 4-aminophenylboronic acid is 1:2.1