Brine extraction is a promising strategy for the management of increased reservoir 2 pressure, resulting from carbon dioxide (CO 2) injection in deep saline reservoirs. The extracted brines usually have high concentrations of total dissolved solids (TDS) and various contaminants, and require proper disposal or treatment. In this article, first by conducting a critical review, we evaluate the applicability, limits, and advantages or challenges of various commerciallyavailable and emerging desalination technologies that can potentially be employed to treat the highly saline brine (with TDS values greater than 70,000 ppm) and those that are applicable to a ~200,000 ppm TDS brine extracted from the Mt. Simon Sandstone, a potential CO 2 storage site in Illinois, USA. Based on the side-by-side comparison of technologies, evaporators are selected as the most suitable existing technology for treating Mt. Simon Brine. Process simulations are then conducted for a conceptual design for desalination of 454 m 3 /h (2,000 gpm)pretreated brinefor near-zero liquid discharge by multi-effect evaporators. The thermal energy demandis estimated at 246 kWh per m 3 of recovered water, of which 212 kWh/m 3 is required for multiple-effect evaporation and the remainder for salt drying. The process also requires additional electrical power of ~ 2kWh/m 3 .

A new class of robust carbon nanotube (CNT) membranes is developed using a scalable chemical vapor deposition method by direct growth of the CNT on a nickel alloy (Hastelloy) mesh with micrometer-sized openings. The developed membranes have a dense, entangled network of CNT with 50-500 nm pore openings and are superhydrophobic. These CNT membranes are resistant to air oxidation up to ~500 °C and chemical corrosion in concentrated HCl or NaCl solutions. Adhesion and utrasonication tests suggest that the developed CNT membranes are resistant to delamination and demonstrate a high interfacial bonding of the grown CNT with the alloy substrate. Potential application of the developed CNT-Hastelloy membranes for separation is explored by conducting membrane distillation tests using a 10,000 mg/L NaCl solution. The developed membranes show similar salt rejection performance compared with a carbon bucky paper membrane. These robust carbon nanotube membranes are reusable and expected to be less susceptible to fouling because of their superhydrophobic properties. Furthermore, if fouled, they can be regenerated by heating in air or using an acid wash.

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Please cite this article in press as: Dastgheib, S.A., et al., Treatment of produced water from an oilfield and selected coal mines in the Illinois Basin. Int. J. Greenhouse Gas Control (2016), http://dx. a b s t r a c tIf large-scale CO 2 sequestration operations are implemented in oilfields or coal mines, large volumes of water (i.e., produced water) could potentially be generated that would need to be properly managed. In this work, produced water samples with total dissolved solids (TDS) values of 18,000-102,000 mg/L (ppm) were collected from an oilfield, a coal-bed methane field, and a coal mine in the Illinois Basin of the United States and were treated by selected conventional pretreatment processes followed by a reverse osmosis desalination process. Pretreatment processes included coagulation by lime, ferric chloride, or aluminum sulfate; filtration by sand, walnut shells, anthracite coal, or microfiltration; and adsorption by organoclay, activated carbon, or ion-exchange resins. Selected pretreatment processes were sufficient for removing most of the contaminants, but the high sodium background of the high-TDS produced water (102,000 ppm) limited the effectiveness of the ion-exchange pretreatment in removing scale-forming species. Reverse osmosis was a practical process for desalination of pretreated produced water samples tested (by reducing the TDS more than 96%) except for the high-TDS produced water. Reported benchscale produced water treatment data might be beneficial for the design and operation of pilot-scale plants for treating produced waters with similar properties.

The feasibility of utilizing lime sludge in the flue gas desulfurization process of coal-fired power plants was evaluated through laboratory-scale studies. Eight lime sludge samples, collected from various water treatment plants, and a high-purity limestone sample were extensively characterized and tested for their ability to capture SO from a simulated flue gas, while investigating the mercury reemission profiles during the scrubbing process. The reactivity of lime sludge samples for acid neutralization was significantly higher than the reactivity of the tested limestone sample. At doses less than that of the limestone sample, the lime sludge materials reduced the SO concentration from 2,000 to <0.5 ppm. The residual lime, higher surface area, and more accessible pores in lime sludge samples were the major factors contributing to their higher reactivity. Concentrations of several elements including B, Mg, Mn, Fe, Cu, Zn, As, Sr, and Ba in some of the tested lime sludge samples were considerably higher than those elements in the limestone. However, no significant leaching of these elements into the scrubber solutions was observed. To investigate mercury reemission during the scrubbing process, ionic mercury was introduced into the simulated slurry and mercury reemission was monitored continuously. Results showed that compared with the limestone sample, the lime sludge samples tested had lower or similar cumulative mercury reemissions. However, different lime sludge samples showed different emission profiles. No conclusive correlation between the composition or trace element content of lime sludge samples and their mercury reemission could be identified. This result was likely due to the oxidative condition of the scrubbing process, which prohibited the reducing species from transforming the ionic mercury into elemental mercury.

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Nitric oxide can be removed from flue gas by catalytic oxidation of NO to NO 2 , followed by dissolution of NO 2 in water. The work presented here includes catalytic NO oxidation by activated carbons (ACs) at atmospheric and elevated pressures under dry and wet conditions at ambient temperature. The AC samples had different physicochemical characteristics including surface areas of ∼400–1600 m 2 /g and micropore volumes of ∼0.2–0.6 cm 3 /g while having different surface chemistries. Dry tests indicated that introducing nitrogen functionalities or coating with pyrolytic carbon could enhance the catalytic activity of AC for NO oxidation. Nitric oxide concentration profiles from the oxidation experiments under dry conditions showed maximum values after 5–15.5 h of testing and a steady-state condition after ∼12–30 h and that a major release of NO 2 began after reaching the maximum values in the NO concentration. Adsorption profiles showed a high rate of NO x adsorption during the early hours of these experiments, and this rate decreased almost exponentially to a near-zero value. A near-complete catalytic conversion was achieved for NO oxidation at 120 psig under dry conditions, substantially higher than the 62% value of the noncatalytic NO oxidation at 217 psig. The wet trickle-bed experiments revealed that an inert packing material with a high external surface was a more suitable option than the ACs for NO oxidation in a wet trickle-bed system, even for ACs that exhibited high catalytic reactivity under dry conditions. Noncatalytic NO oxidation in the trickle-bed system was enhanced by the higher gas–liquid contact surface of the packing material for NO 2 dissolution in water. Complete wetting of the hydrophilic AC or the presence of water vapor in the gas in contact with the surface of the superhydrophobic AC could eliminate or drastically reduce the catalytic activity of the AC for NO oxidation.