Oil-containing dross dehydration process

Abstract

The invention relates to a dewatering technique with chemical regulation and supersonic wave for oil-contained scum. Wherein, after the initial deposition to remove some water, using NaOH or Na2CO3 to regulate the pH value of scum to weak base state; adding flocculant (polyferroaluminium chloride or polyacrylamide) to stir evenly and send to supersonic treatment part for some minutes; then leading into deposition tank or pond to separate scum and water. The treated product can be recovered or send into incinerator for final treatment.

Description

technical field [0001] The invention relates to a process for dehydrating oily scum, in particular to a process for synergistically promoting the dehydration and separation of scum by chemical conditioning and ultrasonic waves. Background technique [0002] Refinery oily scum is the flocculant added to the flotation tank in the wastewater treatment section of the refinery. Under high pressure, a large amount of gas dissolved in the wastewater releases countless fine bubbles when it is suddenly decompressed. The impurity particles in the water stick together to make the oily wastewater coagulate and float, and the tiny air bubbles carry the oily sludge to float up to form oily scum. The water content of these scums is generally 95.5 to 99.5%. [0003] Conventional methods for dehydration of oily scum include biological conditioning, physical conditioning and chemical conditioning. The bioconditioning method can biodegrade the scum, but the scum after treatment is difficult ...

AI Technical Summary

Problems solved by technology

This method will bring secondary pollution to the environment due to the addition of chemical agents.

[0004] Due to the particularity of sewage treatment, the composition and moisture content of the scum formed are quite different. The conventional dehydration treatment method has certain limitations, making it difficult to realize the complete harmless and resourceful utilization of the scum.

At present, domestic relevant patents include CN96114773.3 disclosed in August 1997, which describes a method for finally realizing harmless treatment of scum, but it is difficult to handle scum with a high initial moisture content

Invention patent CN98110574.2 published in May 2000 provides a freezing dehydration separation method, which has high operating costs and is difficult to popularize and apply

In the invention patent of CN02117444.X in November 2002, the demulsification is realized by acidification treatment first, and then the aluminum ions are recovered by alkalization and the liquid-solid separation is realized by pressure filtration. This method has poor dehydration effect

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