Selection of citric acid pipeline valves
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For the pipeline valves used in citric acid production and transportation, 304 stainless steel ball valves are employed. After being in use for about 5 months, when these ball valves were disassembled, it was found that the entire ball body had corroded. How would you choose valves for such situations?
Isn’t this temperature high? If it’s not high, using a fluorinated lining should work well! To be specific, one would need to ask about the materials
What is the medium temperature? If it is below 150 degrees, fluorinated-lined valves can be used.
What is the medium temperature? If it is below 150 degrees, fluorinated-lined valves can be used.
If the temperature is not high – below 120 degrees – and the nominal pressure is below 150 LB, domestic fluorine-lined butterfly valves can be used; if these requirements are not met, then nickel-based alloys have to be chosen instead
For pipelines used in the production and transportation of citric acid, fluorinated-lined valves are recommended: http://www.zghgfm.com
The temperature should be below 40 degrees, and the pressure won’t exceed 1.0 MPa; using one lined with PTFE should be fine.
This post was last edited by Laughing in the World of Love and Romance on 10/09/2012 at 14:53. Personal opinion: Generally, when the temperature permits； For generally corrosive media, we usually prefer fluorinated-lined valves; however, there are various materials used for such valves: perfluoroethylene FEP (F46), which can resist any organic solvents or reagents, as well as dilute or concentrated inorganic acids, bases, hydrocarbons, aromatic compounds, chlorinated hydrocarbons, and more. Operating temperature: -85~150. Features: Its mechanical, electrical properties and chemical stability are essentially the same as those of F4, but its outstanding advantage is high dynamic impact toughness, along with excellent weathering and radiation resistance. Polytrifluoroethylene PCTEF (F3): Suitable media: various organic solvents, inorganic corrosive solutions (oxidizing acids). Operating temperature: -195~120°C. Features: Its heat resistance, electrical properties, and chemical stability are second only to those of F4; its mechanical strength, creep resistance, and hardness are better than those of F4. Polypropylene: RPP: Suitable media: aqueous solutions of inorganic salts, dilute or concentrated solutions of inorganic acids and bases. Operating temperature: -14~80. Features: One of the lightest plastics; it has superior yield, tensile, and compressive strengths as well as hardness compared to low-pressure polyethylene. It offers excellent rigidity, good heat resistance, is easy to mold, and is cost-effective. Modified dynamic impact resistance, fluidity, and bending elasticity. Polyvinyl chloride: Rigid PVC. Media it can withstand: water, concentrated alkalis, non-oxidizing acids, alkanes, oils, and ozone. Operating temperature: 0-55. Features: high mechanical strength, excellent chemical stability and dielectric properties, good oil resistance and aging resistance, easy to weld and bond, and low cost. Media in which polytetrafluoroethylene PTFE (F4) is used: strong acids, strong bases, strong oxidizing agents, etc. Operating temperature: -200~180. Features: It possesses excellent chemical stability, high heat and cold resistance, a very low friction coefficient, making it an excellent self-lubricating material. However, its mechanical properties are low, its fluidity is poor, and it experiences significant thermal expansion. Polyvinylidene chloride PVDF(F2): Medium used: Resistant to most chemicals and solvents. Operating temperature: -70~100. Features: Better ratio of tensile strength to compressive strength compared to F4; resistant to bending, weathering, and radiation. It is resistant to light and aging, etc.; its main advantages are good toughness and easy molding. Polyolefins: PO suitable media: acids, bases, salts at various concentrations, and certain organic solvents. Operating temperature: -58~80. Features: It is currently the most ideal anti-corrosion material in the world, and is widely used as a lining for large-scale equipment and pipe components manufactured by rotational molding. In a situation like yours, it’s best to choose the valve based on your temperature and pH level. To learn more in detail about this, you can add me as a friend or contact me via QQ. . .
Use plastic valves directly – it’s also cheaper!
The material you are using may not meet the required standards; the internal components of the valve have completely corroded. If the material is the same, then why is the valve body intact? There could be two reasons for this: first, if it’s a DN100 or smaller size, the manufacturer might have used hollow balls; second, there could be an issue with the material of the valve core. You can take samples to check the quality of the valve bodies and valve cores in your inventory
The material is fine; physical and chemical tests have been conducted. It’s a hollow sphere; it corrodes too quickly. Now, we’re replacing it with 316 hollow spheres and 304 solid spheres. The market is currently filled with hollow spheres