Corrosive service ball valves
Corrosion is a gradual material loss due to chemical or physical reaction with the process fluid; based on the concentration, temperature and pressure fall, exposed fluid surfaces can cause severe damage to the valve efficiency unless the right sort of valve and equipment are chosen.
Aggressive contaminants or solid particles may be present in the process fluid typically identified as corrosive & dirty applications.
Sulfuric acid (H2SO4), chlorides, moist acid gas (with carbon dioxide, CO2) and dry sour gas (with hydrogen sulphide, H2S) are all corrosive process ingredients.
Corrosion-resistant alloy (CRA) products, overlays or PTFE layer (Halar layer) on exposed stress bearing and maintaining parts should be regarded to avoid valve continuity and minimize the likelihood of failure and leakage. Source materials (Hydrogen Sulphide, H2S) should also comply with NACE MR0175 (ISO 15156) or NACE MR0103 when indicated for pipeline.
High Alloys, Nickel Alloys, Duplex (22Cr – 2 Ni) and Superduplex (25 Cr – 5 Ni) can be supplied according to corrosion resistance requirements as per special material standards (i.e. Norsok MDS D46 and D44 for Duplex, D56 and D54 for Superduplex, or similar standards).
In addition Electroless Nickel Plating (ENP) and 316L SS or Alloy 625 weld overlay are frequently used to enhance corrosion resistance of balls, seats, stems, seat pockets and stem sealing areas, in corrosive service.
Special designs for abrasive mediums, slurry, scaling, fouling and solidifying facilities are included in the our valve range.
What materials are recommended for corrosive service ball valves?
For applications involving corrosive substances such as sulfuric acid or chlorides, it is essential to use ball valves made from materials resistant to corrosion. Common materials include 316 stainless steel, Hastelloy, and PTFE (polytetrafluoroethylene) coatings. These materials provide better durability and performance under harsh conditions.
How does temperature affect the performance of corrosive service ball valves?
Temperature has a significant impact on the performance and lifespan of corrosive service ball valves. Higher temperatures can accelerate the rate of corrosion and may also affect the integrity of the valve materials. It is crucial to select valves that are rated for the specific temperature range of your application to ensure optimal performance and safety.
What maintenance practices are recommended for ball valves in corrosive service?
Regular maintenance is vital for the longevity of ball valves in corrosive service. It is recommended to routinely inspect the valves for signs of wear, leakage, and corrosion. Cleaning the valve surfaces and ensuring that the seals are intact can help prevent failures. Additionally, using valve lubricants designed for corrosive environments can enhance valve performance.