How to remove trace amounts of styrene (as well as trace amounts of acrylonitrile) from water so that the water can be discharged directly
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This post was last edited by liurabbit_PPIS on 2019-1-30 at 13:27. As the title suggests: How can trace amounts of styrene (along with trace amounts of acrylonitrile) be removed from large volumes of water, so that the water can be discharged directly? Option 1: Distillation requires two towers, which is costly; discard it ； Option 2: Use a water-insoluble solvent to extract styrene and acrylonitrile from water. How should this solvent be chosen? Do any of the seniors have any recommendations? Or do any of the seniors have any recommended process flows? Additional note: The organic matter concentration is approximately 100 mg–500 mg/m3; after treatment, it is discharged at a concentration of 20 mg/m3. The maximum processing capacity is 80 t/h.
This kind of question is very vague. What is the specific amount of trace organic matter contained in water? Meeting the emission standards means complying with the emission standards for several types of water.
Before treatment, the concentration of organic compounds such as styrene (along with trace amounts of acrylonitrile) was between 100 mg and 500 mg/m3; after treatment, this concentration was required to be reduced to 20 mg/m3. Such a low concentration makes the extraction process unsuitable, so an adsorption process using adsorbents is preferred, with regular switching over and regeneration via steam stripping. The gas released as a result of stripping is condensed, after which it separates into an oil phase and a water phase. Acrylonitrile has a high solubility in water; the acrylonitrile that is stripped out will dissolve in the condensed water phase. As a result, it is difficult to handle trace amounts of acrylonitrile. The waste gas containing acrylonitrile from the condensed water phase can be sent to an exhaust gas incinerator for treatment, or if its concentration is not high, it can be treated along with the wastewater. As a reminder, according to the \"Emission Standards for Pollutants in the Petrochemical Industry\" (GB 31571-2015), the allowable emission limits for organic characteristic pollutants in wastewater are 0.2 mg/L for styrene and 2 mg/L for acrylonitrile. Therefore, even after the concentration reaches 20 mg/m3, it still cannot be discharged directly, but must be sent to a wastewater treatment system for further treatment (such as biological treatment).
Extraction is carried out using toluene, with a recycling rate of around 10%; approximately 1-2% fresh toluene is added. The water after extraction is stripped using steam, at a stripping rate of 5-8%, which allows the oil content to be reduced to 3-5 ppm
If an adsorption process is used, what substance should be used for adsorption? (Activated carbon?), can adsorption achieve the discharge concentration of 0.2 mg/l that you mentioned?
Are there any reference cases for this data?
Activated carbon is a fairly common adsorbent that can be used, but specialized adsorbents designed for styrene in professional environmental protection companies offer better results. It is advisable to consult such companies specializing in the treatment of petrochemical wastewater; no specific brand names for these specialized adsorbents are recommended here.
Removal using ozone； Activated carbon adsorption filtration ； Reverse osmosis or ultrafiltration
You can also send messages in the \"Environmental Water Treatment\" section under the \"Production\" category to seek contact with professional environmental protection companies.