Selection of pipeline materials for high-salt wastewater
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The existing chemical plant wastewater has a high salt content; the approximate process parameters are as follows: temperature of 110°C, pH of 6–9, flow rate of about 3 m/s, it is a solid-liquid two-phase flow, with TDS > 100,000 ppm, SS around 20,000 ppm, and corrosive chloride ions at > 30,000 ppm. If you are looking to choose a cost-effective pipe material, I would appreciate some suggestions from everyone. Previously, duplex steel and 316L were considered as options, but their cost was too high. . I’m not sure if plastic pipes reinforced with glass fiber are reliable
Carbon steel lined PTFE pipes are very suitable for this application scenario
The main issue is that the carbon steel lining with PTFE is not wear-resistant, and it is not suitable for solid-liquid two-phase flows containing particles in the medium
304 steel cannot be used due to the presence of chloride ions; 316L is too expensive. The PO lining on 20-inch steel pipes is not wear-resistant, and these pipes become prone to corrosion at a pH level of 6. PP and PE pipes cannot withstand temperatures above 110 degrees. It seems that cast iron pipes are the only option left
Have you tried using tubes with an F46 lining? The temperature and corrosion resistance requirements can definitely be met; I’m not sure though whether they can be used in applications involving solid particles
I personally favor the cast iron pipes mentioned above; under medium conditions of 110 degrees, most composite pipes have various issues, and delamination is one of them. In the range of 80 degrees, it is recommended to use steel-reinforced plastic composite pipes – they do not delaminate during single injection molding, combine rigidity and flexibility allowing them to be used in overhead installations, and offer excellent corrosion resistance. I hope this will be helpful to everyone!
The temperature is a bit high; non-metallic pipes cannot be used. It is recommended to use steel-lined PTFE pipes, as they are resistant to high temperatures as well as corrosion. Or consider using ultra-high molecular weight polyethylene pipes.
Glass fiber-reinforced plastic pipes are suitable for transporting the medium mentioned by the poster, but the temperature of that medium is too high; glass fiber-reinforced plastic pipes are only appropriate for temperatures below 90 degrees.
Use 316L pipes; you can buy them from manufacturers at a price much lower than what’s available in your market. I have products available for production; you can contact me within the platform