What are the reasons for the high COD in the water separated from atmospheric and vacuum distillation gasoline?
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What are the reasons for the high COD in the water separated from atmospheric and vacuum distillation gasoline? Our facility is a 350,000 tons per year atmospheric and vacuum distillation unit used to process crude oil from the Zhongyuan oil field. Over the past two months or so, the COD value of the gasoline produced by this unit has remained high, reaching up to 1700 mg/L for Cr. We have yet to identify the cause of this issue; we seek assistance!
It might be a problem with the corrosion inhibitor specified at the top of the tower
Reply to 1# jzs6699: The high COD level in the overhead wastewater is mainly caused by water-soluble phenols, naphthenic acids, and other components present in crude oil
The cut water has a high oil content, the raw material contains high levels of sulfur impurities, or too much dosage is added at the tower top.
Check whether the pH value of the cut water is too high; under alkaline conditions, oil-water emulsification becomes severe, making it difficult to separate the oil from the water.