Questions about the crystalline salts in the MVR process

Simply stir the buffer tank at the set price!

With such a high salt content, evaporation crystallization presents significant problems. Generally, membrane technology is used to separate the salt from nitrate; nitrate can be crystallized at low temperatures, while the salt goes through MVR evaporation crystallization.

If no by-products are produced, there’s no need to separate salt and nitrate. When using MVR + three-effect systems to treat wastewater, the volume of water cannot be too small. The concentrated brine waste stream coming from the centrifuge at the back end of the MVR system can be directly dried using a dryer; it should preferably not be sent for recycling.

MVR can be used, but it produces mixed salt. Add a buffer tank in the middle, and connect it directly to the centrifuge. Return filtrate to mother liquor tank

There must be a crystallizer, and a thickener is needed for discharging the product.

To produce impure salts, it is sufficient to evaporate water vigorously in order to induce salt crystallization. The design of the equipment requires that the size of the crystallizer be determined appropriately to facilitate crystal growth. After crystallization, the material must pass through a thickener before it can be fed into the centrifuge. The production of impure salts has nothing to do with the solubility curve; crystals will form as long as the concentration is high enough. Depending on the type of centrifuge, the solid content in crystal centrifugation varies slightly, with it typically being kept between 35-50%.

Since it’s mixed salt that’s being produced, there are no requirements regarding the quality of the salt. MVR + evaporation tank (heating chamber + salt leg); the crystallized brine is pumped out of the salt leg and sent to a thickener, then to a centrifuge; after centrifugation, the liquid is sent back to the evaporation tank. It is important to note whether there are scaling ions such as calcium, magnesium, and barium in the wastewater; if the concentration of these scaling ions is high, scaling is likely to occur in the heating chamber. Additionally, the evaporation rate must be taken into account to prevent large clumps of salt from forming in the evaporation tank. However, scale inhibitors are now widely used in MVR salt production systems, and they can address the problems of scaling and the formation of large salt crystals. It’s not for advertising; we have been successfully using this product as an antiscalant in MVR salt production for many years, and the results are good.

I have a MVR system with two-effect evaporation; all thickening tanks have been removed. The material from the crystallizer goes directly to the centrifuge via a discharge pump. The bottom valves of these thickening tanks tend to get clogged, and I don’t understand what purpose the manufacturers intended for such tanks. Salt buildup can also cause pipes to become blocked

The salt legs added below the existing two-effect (sodium chloride wastewater evaporation) crystallizers cause the salt discharge pump to get clogged little by little, and this problem has not been resolved to date. The MVR in my home doesn’t have salt legs, and it works extremely well. The new project (new MVR process for treating sodium chloride-containing wastewater) has salt legs, and we have asked the project contractor to resolve this issue as soon as possible. Tomorrow, their manager will bring technical staff to the company to solve the problems; if the issues can’t be resolved, the new project cannot proceed, otherwise it will turn out to be a poor-quality project.

Good discussion topics; thanks for everyone’s opinions, I’ve learned a lot