What is the corrosion resistance of HDPE pipe? Analysis of its application in the chemical industry
How is the corrosion resistance of HDPE pipe? Analysis of chemical industry application
HDPE (high-density polyethylene) pipe is widely used in the chemical industry due to its excellent corrosion resistance. The following is a detailed analysis of its corrosion resistance characteristics and chemical industry applications:
Corrosion resistance characteristics of HDPE pipe
Strong chemical inertness
HDPE is a non-polar polymer material that shows strong resistance to most acids, alkalis, salts, organic solvents and other chemical substances, especially at room temperature:
Acids: hydrochloric acid (HCl), sulfuric acid (H₂SO₄, concentration ≤50%), phosphoric acid (H₃PO₄), etc.
Alkali: strong alkaline solutions such as sodium hydroxide (NaOH) and potassium hydroxide (KOH).
Salts: sodium chloride (NaCl), ammonium chloride (NH₄Cl), etc.
Organic solvents: polar solvents such as alcohol and glycerin (but poor tolerance to non-polar solvents such as gasoline and benzene).
No risk of electrochemical corrosion
Unlike metal pipes, HDPE does not suffer from electrochemical corrosion (such as pitting and intergranular corrosion), and is suitable for use in highly corrosive environments such as moisture and salt spray.
Environmental stress cracking resistance (ESCR)
Through modification (such as PE100 grade materials), HDPE pipes can resist stress cracking and extend their service life in chemical media.
Limitations
Strong oxidants: such as concentrated nitric acid (HNO₃) and concentrated sulfuric acid (>50%) will slowly oxidize HDPE.
Halogenated hydrocarbons: such as carbon tetrachloride (CCl₄) may cause swelling.
High temperature effects: Long-term exposure to environments above 60°C or certain chemical media may reduce performance.
Application scenarios in the chemical industry
Corrosive media transportation
Acid and alkali solutions: waste acid (dilute sulfuric acid, hydrochloric acid) and alkali (NaOH) transportation in electroplating plants.
Brine/brine: brine pipelines and seawater desalination systems in the chlor-alkali industry.
Chemical wastewater: collection and discharge of corrosive wastewater containing heavy metal ions, sulfides, etc.
Environmental protection and waste gas treatment
Waste gas scrubber pipeline: resistant to corrosive condensate formed by acidic gases such as SO₂ and HCl.
Sewage treatment plant: aeration pipeline, sludge transportation pipeline (resistant to hydrogen sulfide corrosion).
Chemical equipment matching
Storage tank lining: as the inner lining of metal storage tanks, prevent chemicals from directly contacting metals.
Underground pipeline: replace steel pipelines to avoid soil electrolytic corrosion (pay attention to ultraviolet protection).
Special process requirements
Electrolysis workshop: brine pipeline of ion membrane electrolyzer (resistant to chloride ion corrosion).
Pharmaceutical industry: high-purity water or solvent transportation (no metal ion precipitation pollution).
Selection and construction considerations
Material grade selection
PE80/PE100: Chemical industry recommends PE100, with higher density and chemical resistance.
UV-resistant version: Carbon black or UV stabilizer needs to be added for outdoor use.
Connection method
Hot-melt connection: No leakage risk, suitable for high-pressure systems.
Electrofusion connection: Ensure sealing under complex working conditions.
Temperature and pressure design
Chemical pipelines need to adjust the pressure level according to the medium temperature (such as derating above 40°C).
Compatibility test
For special media (such as organic solvents), it is recommended to conduct long-term immersion experiments to verify the stability of the material.
Advantages compared with other materials
Feature | HDPE Pipe | PVC Pipe | Stainless Steel Pipe | FRP Pipe (Fiberglass) |
Acid Resistance | ★★★★★ | ★★★☆☆ | ★★☆☆☆ (304) | ★★★★★ |
Alkali Resistance | ★★★★★ | ★★★☆☆ | ★★★★★ | ★★★★☆ |
Soil Corrosion Resistance | ★★★★★ | ★★★★☆ | ★★☆☆☆ | ★★★★★ |
Cost | Low | Lowest | High | Medium-High |
Ease of Installation | High | High | Medium | Low |
The advantages of HDPE pipes in the chemical industry are their comprehensive corrosion resistance, light weight and low cost, and they are particularly suitable for the transportation of corrosive media at medium and low pressures and room temperatures. However, for high temperature (>60°C), strong oxidants or non-polar solvents, it is necessary to carefully evaluate or select modified HDPE (such as cross-linked polyethylene PEX) and other materials (such as PTFE-lined steel pipes). In practical applications, it is recommended to combine parameters such as medium concentration, temperature, and pressure, and refer to chemical pipeline design specifications such as "HG/T 20538-2016" for selection.
Official website: www.phtopindustry.com | www.phpipes.com
Contact us: Email:inquiry@phtopindustry.com | Whatsapp:+86 15093100892
Company address: Room 802, 8th Floor, Building 5, Jinyin Modern City, Jinshui District, Zhengzhou City, Henan Province, China
