Seeking advice on oil contamination in the wastewater from the atmospheric and vacuum distillation towers
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The oil content in the wastewater from the tops of the atmospheric and vacuum distillation units in our company was 64.45 and 65.79 respectively; the sampled liquid had a milky white color and was in an emulsified state. We’re not sure whether this is normal. Furthermore, in the later stage, the acid water stripping unit fails to achieve an effective oil-water separation after receiving raw water, which affects the operation of the stripping tower and leads to tower flooding. I would appreciate it if experts could explain whether this is normal, and if not, whether there are any proven solutions available.
Demulsification was not done properly; change the demulsifier
Have the corrosion inhibitor manufacturer modify the formula by adding some demulsifying components.
The level of the constant-top reflux tank should be kept as low as possible
This isn’t very useful. Emulsifiers are added during oil extraction, and demulsifiers must be used in processing at atmospheric pressure.
I’ve encountered this before: 1. The issue of residence time – adding a reverse demulsifier can help, and it does provide some effect; it’s also possible to install an oil-water separation tank to increase the residence time of the wastewater at the top of the tower. 2. The issue related to the type of crude oil.
Iron ions in sulfur-containing wastewater – is the pH value within the acceptable range? If the sulfur-containing wastewater appears milky and oily, it indicates emulsification; you can reduce the amount of corrosion inhibitor used or stop using it altogether to observe the situation
The pH and iron ions are still within acceptable levels; there is no significant oil content, and it remains milky white even after being left to stand.
It is estimated that the wastewater (condensate) from the atmospheric and vacuum distillation towers is recycled; research has been conducted on this topic. The wastewater from the towers is in an emulsified, milky white state, with a COD level of 1500 mg/L. By adding demulsifiers, the wastewater becomes clear, with a COD level of less than 200 mg/L.
What kind of demulsifier did you use, and what type of crude oil was processed?