Reverse osmosis membrane
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Which domestic company is good at reverse osmosis? What is the limit for the concentration of sodium chloride in brine?
Reply to 1# fzbqxh: We can achieve 10-15, it depends on the circumstances
Reply to 2# dawenzi123: If the concentration is increased to 15%, what will the operating cost be?
Reply to 3# fzbqxh: If it’s NaCl, it’s not possible to achieve 15% purity using RO; currently, 6% is already considered a high level in seawater desalination processes. If the NaCl content is to be increased to 15%, membrane distillation is recommended over RO. If you’re interested, we can talk about it.
If using reverse osmosis, it might be challenging; for reverse osmosis, the osmotic pressure of 10,000 PPM NaCl is 7.9 bar. If the target concentration is 70,000 ppm, then the osmotic pressure is around 56 bar. Filtration certainly requires a flow rate, and pressure is needed to drive this flow rate; the additional pressure required for the flow rate is generally 6–8 bar. Therefore, seawater desalination around the world is carried out at pressures below 70 bar, that is, by concentrating 3.5% NaCl to double it, resulting in a NaCl solution with a concentration of 7%. Additionally, what you mentioned might refer to the separation of NaCl and NaSO4 in the chlor-alkali industry; the use of nanofiltration membranes NF may not present any restrictions, but the yield of NF-based products is low, their performance is unstable, and the quality varies, making them less reliable than RO-based products.
Concentrated to 15%, with an osmotic pressure of around 120 bar; the RO method is used, and when the pressure is insufficient, forward osmosis may occur – that is, the water produced on the permeate side penetrates into the feed solution side, diluting your concentrated product.
Reply to 4# Benjamin315: We are working on a project that produces 3 million tons per year of 5% pure brine, which can be used directly for membrane electrolysis. But the problem is that the brine system cannot handle such a large volume; to increase the concentration to 20% or higher, what are some good methods for using fresh water as process water? Achieve the lowest operating costs. If anyone has relevant materials or information to share, please send it to my email lnjhqxh@126.com
This post was last edited by Benjamin315 on 2011-3-25 at 23:39. Reply 7# fzbqxh: It’s definitely impossible to concentrate it to 20% using RO. If membrane distillation is used, it is best for such plants to be located near large thermal power plants, so that the waste heat steam generated by those plants can be utilized. Otherwise, there is only multi-effect evaporation. My QQ number is: 1551626477.
I wonder if it would be feasible to first pre-concentrate using RO and then further concentrate it through membrane distillation I work in membrane cleaning; I’m not very expert in this type of production. The above are purely my personal opinions! Please forgive any mistakes!