Mother liquor drying – A drying method for the mother liquor obtained after the concentration of sodium sulfate wastewater
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This post was last edited by AiDrying on 2021-2-21 at 12:56. Drying of mother liquor – A drying scheme for the mother liquor obtained after the concentration of sodium sulfate wastewater. High-salt wastewater refers to wastewater with a total dissolved solids content of more than 3.5%, and it contains inorganic salts such as chloride ions, sodium ions, and sulfate ions, with a mass fraction of at least 1% expressed in terms of sodium chloride. Such wastewater originates from processes such as zero-discharge systems, salting out, distillation, and membrane separation in fine chemical industries like pharmaceuticals, pesticides, and coal chemicals. Its composition is complex, its quality varies greatly, and it is difficult to treat. Currently, domestic enterprises mostly use mechanical vapor recompression (MVR) and multi-effect evaporation to concentrate and reduce the volume of waste liquids. However, high-salinity wastewater contains a large amount of high-boiling-point organic compounds, which cannot volatilize along with water vapor during the evaporation process, nor can they be included in the solid salts formed after concentration. Therefore, these organic residues remain in the crystallization mother liquor; as the mother liquor becomes more concentrated, the amount of impurity ions increases, which reduces the quality of the resulting salt. Hence, it is necessary to periodically discharge the mother liquor in order to minimize the impact of impurity ions on the quality of the salt. For such residual mother liquors at present, our company has developed a new process for reducing the volume and drying mixed-salt mother liquor wastewater, based on existing technologies. This process involves the continuous concentration and evaporation of high-salt wastewater using multi-effect or MVR systems, with the resulting concentrated mixed-salt solution being directly dried using a drum scraper dryer. The evaporated water vapor is discharged after dust removal through a water film. Taking into account the characteristics of high-salt and high-COD wastewater, the treatment steps for wastewater containing miscellaneous salts are reduced, thereby enabling the reduction and drying of the wastewater.
This is the mother liquor from multiple MVR concentration steps being further dried using a rake dryer; is there any company that subjects this mother liquor to advanced oxidation before sending it back to the MVR for dehydration? lol
It’s not about drying it with a rake; it’s new technology, new processes
Isn’t it usually the case that the material is simply sent back for evaporation and concentration? Can adding another mother liquor dryer really solve the problem related to the quality of the salts? :lol
This post was last edited by Love Drying on 2021-7-16 at 09:04. Reusing the concentrate represents the ideal state for achieving \"zero emissions,\" but many projects have to discharge a portion of it regularly – namely those concentrated liquids that cannot be evaporated, as they are rich in organic substances, sodium chloride, sulfuric acid, and other compounds. By using mother liquor dryers to dry out this waste liquid containing impurities, the amount of impurities throughout the evaporation system is significantly reduced. This makes it easier to produce by-products such as crystalline salts like sodium sulfate/sodium chloride/ammonium chloride of industrial first-grade quality. Mother liquor drying is a reduction drying process that directly evaporates the concentrate, reducing energy consumption by 2/3 compared to traditional spray treatment.
The idea is excellent; it’s good to return the centrifuged mother liquor to the MVR unit after oxidation and decolorization. The key is that high-boiling-point organic compounds can be carried away with the product, thus achieving equilibrium.
It’s the drum dryer, right? What material is your scraper made of?