Process and system suitable for treating produced water with ultra-high salinity

Abstract

The invention discloses a process and a system suitable for treating produced water with ultra-high salinity, the produced water with ultra-high salinity firstly enters a cyclone flotation separator, floating oil and finely dispersed oil are separated and recovered to a dirty oil settling tank, and large-particle sludge is discharged to an oil sludge concentration tank; outlet water of the separator and an alkaline clear water type demulsifier are mixed and input into a demulsification reaction tank for demulsification and destabilization, after being lifted by a pump and mixed with a cationic organic flocculant, the mixture is sequentially input into a settling separation tank, floating oil is recycled to a dirty oil receiving tank, and suspended solids form floc precipitates and are discharged into an oil sludge concentration tank; the effluent of the settling separation tank is lifted by a pump to enter a multi-medium filter, the effluent is treated until the oil content, the suspended solid content and the particle size median index of the produced water meet the reinjection standard and then is output, and backwash filter residues are sent to a sludge concentration tank; dewatered sump oil is sent to a crude oil treatment process, and concentrated sludge is sent to be dewatered and dried. The process has the advantages of high oil recovery rate, low oily sludge yield, simple process and equipment operation, low operation cost and the like.

Description

technical field [0001] The invention belongs to the technical field of oil field produced water treatment, and relates to a purification process and a system for separating petroleum and suspended solids in ultra-high salinity produced water. Background technique [0002] The salinity of ultra-high salinity produced water is usually above 200,000 mg / L, which is composed of oil, solid impurities, dissolved gases (such as H 2 S, CO 2 ) and soluble salts and other multi-component heterogeneous complex systems. It has the characteristics of high emulsification degree, high oil content, high salt content, high hardness, high suspended solid content, low pH value, etc.; 2+ and / or sulfide (S 2- ), also showed the characteristics of unstable water quality and strong corrosiveness. Purification and deep separation of oil and suspended solids are the prerequisites for reinjection of ultra-high salinity produced water. [0003] In the actual project of ultra-high salinity produced...

AI Technical Summary

Problems solved by technology

[0009] The invention is developed aiming at the problems existing in the existing ultra-high salinity produced water purification treatment process

Solve the complex process and equipment, the mismatch between the functional design and effect of the process unit, the low treatment efficiency of the process unit, the type and dosage of chemicals are too large, the oil recovery rate is low and the quality is poor, and the amount of by-product oily sludge is too large And other issues

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