How to select the plate material of the brazed plate heat exchanger according to the characteristics

Source: 　 Time: 2025-06-04 11:05:06　Hit:

When selecting the plate material of the brazed plate heat exchanger based on the characteristics of the medium, multiple dimensions such as the corrosiveness of the medium, working temperature and pressure, physical properties of the fluid, and cleanliness requirements need to be comprehensively considered.

Corrosion resistance analysis

The corrosiveness of the medium is the core factor in choosing the material of the plate. The adaptability of different materials to different corrosive environments varies:

Stainless steel: such as 304, 316, 316L, etc., has excellent corrosion resistance and is suitable for most non-corrosive media. In an environment with a relatively low concentration of chloride ions (Cl⁻) (such as Cl⁻ < 200 mg/L), 304 or 316 stainless steel can meet the requirements. However, in environments with high chloride ion concentrations (Cl⁻ > 200 mg/L) or strong acids and alkalis, higher-performance stainless steels such as 316L or 254SMO should be selected.

Titanium alloy: Titanium has excellent corrosion resistance and is especially suitable for chlorine-containing media (such as seawater, brine, etc.). Titanium performs well in seawater below 135℃ and brine below 165℃, but it may cause crevices corrosion or stress corrosion in high temperatures (>120℃) or high-concentration chloride solutions. In such cases, titanium-palladium alloys can be selected.

Nickel-based alloys: such as Hastelloy C-276, Incoloy 825, etc., are suitable for strong acids, strong alkalis and high-temperature and high-pressure environments, and perform exceptionally well especially in media containing sulfides or oxidizing substances.

Hastelloy alloys: such as C-276, B-3, etc., are suitable for strong corrosive media such as concentrated sulfuric acid, hydrochloric acid, and phosphoric acid.

Copper alloy: It is suitable for media with high thermal conductivity requirements, but has poor resistance to some corrosive media (such as concentrated sulfuric acid and nitric acid).

2. Temperature and pressure boundary conditions

The material of the plate needs to meet the working temperature and pressure requirements of the equipment:

- High-temperature environment: At high temperatures (>250℃), titanium alloys or nickel-based alloys are the better choice due to their excellent high-temperature resistance.

- High-pressure environment: Under high pressure (>45 BAR), materials with high strength and good welding performance, such as 316L stainless steel or titanium alloy, should be selected.

Extreme conditions: In extremely corrosive or high-temperature and high-pressure environments, it is advisable to consider using special coatings or casting and forging structures to enhance corrosion resistance and mechanical strength.

3. The principle of physical property compatibility

For high-viscosity media: It is necessary to select plate designs with larger flow channels and higher heat transfer efficiency, such as wide flow channel plates or large-angle corrugated plates.

For media containing solid particles: Materials with good wear resistance should be selected, such as silicon carbide coating or Hastelloy B-3.

- Media prone to scaling: Materials with smooth surfaces that are not prone to scaling should be selected, such as electrolytically polished stainless steel or plastic plates.

4. Economic balance

- Precious metal materials: such as titanium alloys, nickel-based alloys, etc. Although they have strong corrosion resistance, their cost is relatively high. The cost can be optimized through local lining or modular design.

- Multi-media shared system: It is recommended to adopt a modular design, and configure plates of different materials in sections according to the characteristics of the media, taking into account both performance and economy.

5. Applicability to specific media

For acidic media such as sulfuric acid and phosphoric acid, 316L stainless steel, 254SMO, titanium alloy or nickel-based alloy can be selected.

Alkaline media: Such as caustic alkali solutions, nickel-copper alloys, duplex steel 2205 or titanium alloys can be selected.

- Seawater and brine: Titanium alloys or titanium-palladium alloys are preferred due to their excellent corrosion resistance in chlorine-containing environments.

- Organic solvents: such as ethylene glycol, mineral oil, etc. Stainless steel or titanium alloy can be selected.

- Gas medium: such as ammonia, nitrogen, etc. Stainless steel or titanium alloy can be selected.

6. Thickness and processing performance

- Plate thickness: The thickness of stainless steel plates is usually above 0.5mm, while the thickness of titanium alloy plates needs to be appropriately increased to balance performance and cost.

- Ductility: Austenitic stainless steel has excellent ductility and is suitable for cold pressing processing. However, titanium alloys have poor ductility, so attention should be paid to the processing technology.

7. Standards and Norms

National standards: The material of the plates in plate heat exchangers should comply with standards such as GB/T 3280 and NB/T 47004.

- Industry standards: For example, FRIGOTHERM Company recommends the use of 1.4404 / AISI 316L, 1.4547/254 SMO, Alloy C276 and titanium materials, etc.

Summary

When choosing the plate material of the brazed plate heat exchanger, a comprehensive evaluation should be conducted based on the characteristics of the medium such as corrosiveness, temperature, pressure, viscosity and particle content. Stainless steel, titanium alloy, nickel-based alloy, etc. are common choices. The specific material needs to be weighed based on the actual working conditions and economy. At the same time, relevant standards and norms should be referred to to ensure the scientific and reasonable nature of material selection.

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