Flotation, Filtration, and Adsorption: Pilot Trials for Oilfield Produced-Water Treatment

Abstract

Summary As an oil field matures, it produces larger quantities of produced water. Appropriate treatment levels and technologies depend on a number of factors, such as disposal methods or usage aims, environmental impacts, and economics. In this study, a pilot plant with a capacity of 50 m3/day was used to conduct flotation, filtration, and adsorption trials for produced-water treatment at a crude-oil gathering facility. The flexible design of the plant allows for the testing of different combinations of these processes on the basis of the requirements of the water to be treated. The subject water during this study was a complex and changing mixture of brine and oil from different oil fields. Induced-gas-flotation (IGF) trials were conducted, with different coagulant [poly-aluminum chloride (PAC)] -addition rates from 0 to 820 mg•L-1. Inlet-dispersed oil-in-water (OIW) concentrations were quite varied during the trials, ranging from 39 to 279 mg•L-1 (fluorescence-analysis method). Turbidity also varied, ranging from 85 to 279 FTU. Through coagulation/flocculation and flotation, dispersed oils were removed from the water. PAC addition ranging from 60 to 185 mg•L-1 resulted in the reduction of the dispersed-oil concentration to less than 50 mg•L-1 in treated water; and PAC addition ranging from 101 to 200 mg•L-1 resulted in the reduction of the dispersed-oil concentration to less than 15 mg•L-1 in treated water. Turbidity was also reduced through flotation, with trial average reductions ranging from 57 to 78%. Filtration further reduced turbidity at rates greater than 80% through the removal of any suspended solids remaining from flotation. Activated-carbon adsorption reduced OIW concentrations of flotation-/filtration-treated water to 5 mg•L-1 (infrared-analysis method) through the removal of dissolved oil remaining in the water. Results confirmed that such adsorption treatment would be more practical for water with lower chemical-oxygen-demand (COD) concentration because high-COD concentrations in water reduce the lifetime of activated carbon dramatically.

Improving Performance of Electrospun Nylon 6,6 Nanofiber Membrane for Produced Water Filtration via Solvent Vapor Treatment

“…Generally, there are several conventional separation methods that are applicable for produced water (PW) treatment. Some of the methods are coagulation/flocculation [1,2], adsorption [3,4], hydrocyclone [5,6], and floatation [3,7]. All of them have merits and shortcomings and are more favourable than others under certain circumstances.…”

An Environmentally-Friendly Method for Disposal of the ASP Flooding Produced Water

“…In addition, the concentrations of injection chemicals in the water after disposal were reduced by half compared with the raw produced water, this result is in particle size, μm differential distribution, % cumulative distribution, % real line: raw water broken line: after disposal agreement with a low Zeta potential value (nearly -15mV) of the effluent water with this physical separation method. The suspended sludge blanket with adsorption, filtration, electrical neutralization and net intercepting effects cooperated with the flocculant can promote the small size particles in produced water to flocculate and enlarge, so that the water can be purified efficiently 14,15 . As shown in Fig.…”

Study on the Stability of Produced Water from Alkali/Surfactant/Polymer Flooding under the Synergetic Effect of Quartz Sand Particles and Oil Displacement Agents

“…In recent years, a large number of research works have been studied on the treatment of ASP-flooding-produced water at home and abroad, mainly focusing on the effects of oil displacement agents on the properties of the oil-water interface [5,6,8], the screening of chemical agents [9,10] and the improvement of treatment equipment [11,12]. Deng Shubo et al studied the effect of oil displacement agents on the stability of ASP-flooding-produced water and found that the surfactant had the greatest influence on the stability of oil droplets, which hindered the coalescence of oil droplets and increased the difficulty of oil-water separation [6].…”