Desalination Of Produced Water Research Articles

Produced water desalination: An exploratory study

Produced water is the largest volume byproduct stream in oil and gas production, and has an adverse environmental impact due to its complex composition and high disposal costs. Membrane fouling due to hydrocarbons limits purification of produced water by reverse osmosis (RO). A novel hybrid adsorption/ion exchange (IEX)/RO process is developed in which the adsorber removes dissolved hydrocarbons, IEX removes scale causing precursors, and RO desalinates the water. A part of the hydrocarbon free liquid from the adsorber is pressurized to 6.2bar, heated to 160°C and used to regenerate the adsorber, which resulted in an improvement in water recovery (to 86%), and translated into a predicted 22.8% decrease in costs amounting to US$27million annual savings. The new high water recovery processes delineated in this work provide an array of novel options for removing hydrocarbons and desalination under different conditions. Experimental studies are needed to verify the assumptions made in this analysis.

Experimental study of PES/SiO2 based TFC hollow fiber membrane modules for oilfield produced water desalination with low-pressure nanofiltration process

In this study, a PES/SiO2 based thin film composite (TFC) hollow fiber membrane (HFM) was prepared for the oilfield produced water desalination with low-pressure nanofiltration process. The effects of operating parameters including pressure, salt concentration and time, on the salt rejection were investigated. The results showed that the salt rejection increased linearly with an increase in operating pressure from 50psi to 80psi, decreasing slightly with a further increase in pressure to 100psi. The increased salt concentration resulted in a decrease in salt rejection. A solution diffusion theory-based model was proposed to well explain the laboratory testing results.

Vacuum enhanced direct contact membrane distillation for oil field produced water desalination: specific energy consumption and energy efficiency

This paper presents a study for energy requirements of lab-scale membrane distillation (MD) unit. This lab unit consists of flat-sheet membrane module with two circulation pumps, heater, and cooler to study the effect of different operating conditions on both specific energy consumption (SEC) and energy efficiency (ηE) via vacuum enhanced direct contact MD method. The flux and the two parameters of energy (SEC, ηE) were measured using different temperatures, different feed flow rates, and different feed salt concentrations. The two membranes used were neat polypropylene (PP) membrane and PP/multi-walled carbon nanotubes (MWCNTs) composite membrane. The membranes were synthesized via phase inversion process, using xylene as a solvent, methyl iso-butyl ketone as a coagulant and dispersion medium for MWCNTs. The results showed that the highest ηE was 39.5 with SEC 1,649.2 kW h/m3 at flux 52.5 kg/m2 h using 15 L/min feed flow rate of synthetic feed water with salt concentration 10,000 ppm at 55°C feed temperature. On the other hand, using our prepared membrane for the desalination of oil field water, the values of ηE and SEC were 12.1 and 4,189.5 kW h/m3, respectively.

Performance assessment of synthesized CNT/polypropylene composite membrane distillation for oil field produced water desalination

Multi-walled carbon nanotubes (MWCNTs)/polypropylene (PP) blend membranes were synthesized by phase inversion process, using xylene as a solvent and methyl isobutyl ketone (MIBK) as a dispersion medium for MWCNTs. The prepared MWCNTs/PP membranes were characterized using several analytical techniques such as: attenuated total reflections Fourier transform infrared spectroscopy, contact angle measurement, atomic force microscope (AFM), and scanning electron microscope (SEM). Performance of the synthesized membranes in vacuum-enhanced direct contact membrane distillation (VEDCMD) process was evaluated using 55°C feed synthetic water and/or oil field produced water samples with salinities up to 230,000 ppm. Effect of membrane preparation conditions, including polymer concentration, polymer thickness, and CNT concentrations as well as operating temperatures and streams flow rates on the flux were studied. The results showed an improvement in membranes characteristics and trans-membrane flux by MWCNTs addition. Contact angle measurements indicate that the hydrophobicity of MWCNT/PP membrane was significantly increased compared to the pure PP membrane. The SEM images showed a well dispersion of MWCNTs in the PP matrix. By analyzing AFM images, the roughness parameters and mean pore size increase by either using MIBK or decreasing PP polymer concentration. On the other hand, by blending MWCNTs, the roughness parameters increase with decreasing of mean pore size. The salt rejection of the synthesized membranes was greater than 99.9%. The results show that MWCNTs enhanced the performance of VEDCMD with 58% at the same operating conditions. The obtained flux ranged from 45.95 to 19.66 L/m2 h, using 10,000 ppm and brine oil field produced water, respectively, by MWCNT/PP nano-composite membrane with 5 mg/g of MWCNTs and thickness 50 μm.

Desalination and Reuse of High-Salinity Shale Gas Produced Water: Drivers, Technologies, and Future Directions

In the rapidly developing shale gas industry, managing produced water is a major challenge for maintaining the profitability of shale gas extraction while protecting public health and the environment. We review the current state of practice for produced water management across the United States and discuss the interrelated regulatory, infrastructure, and economic drivers for produced water reuse. Within this framework, we examine the Marcellus shale play, a region in the eastern United States where produced water is currently reused without desalination. In the Marcellus region, and in other shale plays worldwide with similar constraints, contraction of current reuse opportunities within the shale gas industry and growing restrictions on produced water disposal will provide strong incentives for produced water desalination for reuse outside the industry. The most challenging scenarios for the selection of desalination for reuse over other management strategies will be those involving high-salinity produced water, which must be desalinated with thermal separation processes. We explore desalination technologies for treatment of high-salinity shale gas produced water, and we critically review mechanical vapor compression (MVC), membrane distillation (MD), and forward osmosis (FO) as the technologies best suited for desalination of high-salinity produced water for reuse outside the shale gas industry. The advantages and challenges of applying MVC, MD, and FO technologies to produced water desalination are discussed, and directions for future research and development are identified. We find that desalination for reuse of produced water is technically feasible and can be economically relevant. However, because produced water management is primarily an economic decision, expanding desalination for reuse is dependent on process and material improvements to reduce capital and operating costs.

Influence of counter ions on the reverse osmosis through MFI zeolite membranes: implications for produced water desalination

Desalination of brines produced from oil and gas fields is a potential resource for potable water in the southwestern U.S. and other semi-arid areas. Oilfield brines typically contain high concentrations of Na + and Cl −, as well as other multivalent cations and anions that can reduce efficacy of reverse osmosis (RO). RO separation of NaCl solutions at existence of other co-ions or at increased ion concentration and operating pressure was experimentally tested on a pure silicalite zeolite membrane. Water fluxes increase linearly with increase of net driving force (Δ P−Σ r i RTC c,f ). Ion flux is essentially independent of the operating pressure but increases exponentially by a power factor of 1.13 as feed concentration increases from 0.001 M to 0.3 M. Inorganic cations (K +, Ca 2+, and Al 3+) and anions (Br −, and SO 4 2−), when present in a 0.01 M NaCl solution, play an important role on separation performance of the NaCl solutions. A notable variation of water flux and ion rejection in the presence of counter cations was observed, while the permeation behavior of 0.01 M NaCl solution was hardly affected by counter anions. This study is part of a broader project seeking to make desalination of oilfield-produced waters economically viable.