Process for preparing functional heat transfer surface

Abstract

The present invention relates to heat transfer and energy saving technology, and is especially technology of modifying metal surface with functional coating and applying the modified metal surface in heat exchanger. The present invention features that paint is coated in the surface of heat exchanger and high temperature heat treated to resist corrosionú¼resist scale and raise heat efficiency. The coating contains fluoro resin in 60-70 wt%, adhesion promoting resin 20-25 wt%, heat conducting stuffing 5-10 wt%, and nanometer particle 0.5-3 wt%, and has thickness of 5-15 micron and thermal conductivity of 0.3-1.5 W / m.K. The coating makes condensed water in the heat exchange surface form drops with high heat conductance, and results in high anticorrosion and long service life of the coated heat exchanger.

Description

technical field

[0001] The invention belongs to the technical field of heat transfer enhancement and energy saving, and relates to a functional heat transfer surface material and a preparation method thereof. In particular, it relates to the modification of metal surfaces with functional coatings and the application of the modified metal surfaces to heat exchange equipment. Background technique

[0002] The steam condensation heat transfer process has a wide range of application backgrounds in the fields of chemical industry, refrigeration, power generation, power and aerospace thermal control technology. The condensation form of condensate on the heat transfer surface is an important factor affecting the condensation heat transfer efficiency. The thermal coefficient is much higher than the heat transfer coefficient of film condensation, but most of the condensation surfaces commonly used in industry are metal materials, that is, easy-to-wet surfaces, so film condensation is...

Examples

Embodiment 1

[0028] Coating PVDF modified coating on the surface of copper condensation block, adding Cr with a mass content of 2% to polyvinylidene fluoride resin emulsion 2 o 3 Nanoparticles, particle size 100-200 nanometers; 1000 mesh copper powder 2%; grind for 72 hours, filter with 600 mesh screen, and then disperse with ultrasonic wave for 30 minutes; air spray, pressure 0.4MPa. The surface treatment process includes degreasing, roughening, and drying; the heat treatment process is heated up in stages under the protection of nitrogen, and the heating rate is 3°C / min before 130°C, and the temperature is kept at 130°C for 15 minutes to ensure that the solvent volatilizes slowly. Keep warm at 280°C for 30 minutes to fully plasticize and level the coating; cool slowly at a cooling rate of 3°C / min to reduce the internal stress between the coating and the substrate.

Embodiment 2

[0030] Coating PFA emulsion paint on the surface of red copper, CuO nano particles, the mass content is 1.5%; the copper powder mass content is 3%, the particle size is less than 5 microns; the dispersant pre-disperses the nanoparticles, and it is added while stirring the PFA emulsion. After fully stirring, add copper powder, grind and disperse, filter, ultrasonically disperse, and spray. The heat treatment process is carried out in stages under the protection of nitrogen, from room temperature to 150°C at a rate of 3°C / min, holding for 30 minutes, continuing to heat up to 380°C at a rate of 5°C / min, holding for 30 minutes, and then cooling down to room temperature at a rate of 5°C / min.

Embodiment 3

[0032] Coating PVDF coating on the surface of the brass tube, containing 3% copper powder particles and 2% nano-CuO, the construction process refers to Example 1.

technical field

[0001] The invention belongs to the technical field of heat transfer enhancement and energy saving, and relates to a functional heat transfer surface material and a preparation method thereof. In particular, it relates to the modification of metal surfaces with functional coatings and the application of the modified metal surfaces to heat exchange equipment. Background technique

[0002] The steam condensation heat transfer process has a wide range of application backgrounds in the fields of chemical industry, refrigeration, power generation, power and aerospace thermal control technology. The condensation form of condensate on the heat transfer surface is an important factor affecting the condensation heat transfer efficiency. The thermal coefficient is much higher than the heat transfer coefficient of film condensation, but most of the condensation surfaces commonly used in industry are metal materials, that is, easy-to-wet surfaces, so film condensation is...

Examples

Embodiment 1

[0028] Coating PVDF modified coating on the surface of copper condensation block, adding Cr with a mass content of 2% to polyvinylidene fluoride resin emulsion 2 o 3 Nanoparticles, particle size 100-200 nanometers; 1000 mesh copper powder 2%; grind for 72 hours, filter with 600 mesh screen, and then disperse with ultrasonic wave for 30 minutes; air spray, pressure 0.4MPa. The surface treatment process includes degreasing, roughening, and drying; the heat treatment process is heated up in stages under the protection of nitrogen, and the heating rate is 3°C / min before 130°C, and the temperature is kept at 130°C for 15 minutes to ensure that the solvent volatilizes slowly. Keep warm at 280°C for 30 minutes to fully plasticize and level the coating; cool slowly at a cooling rate of 3°C / min to reduce the internal stress between the coating and the substrate.

Embodiment 2

[0030] Coating PFA emulsion paint on the surface of red copper, CuO nano particles, the mass content is 1.5%; the copper powder mass content is 3%, the particle size is less than 5 microns; the dispersant pre-disperses the nanoparticles, and it is added while stirring the PFA emulsion. After fully stirring, add copper powder, grind and disperse, filter, ultrasonically disperse, and spray. The heat treatment process is carried out in stages under the protection of nitrogen, from room temperature to 150°C at a rate of 3°C / min, holding for 30 minutes, continuing to heat up to 380°C at a rate of 5°C / min, holding for 30 minutes, and then cooling down to room temperature at a rate of 5°C / min.

Embodiment 3

[0032] Coating PVDF coating on the surface of the brass tube, containing 3% copper powder particles and 2% nano-CuO, the construction process refers to Example 1.

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