|Swellable Organosilica Materials to Clean Produced Water
||Last Reviewed 6/24/2014
The goals of this project are to (1) develop and improve several water treatment technologies to remove dispersed and dissolved organic species from produced water with a focus on flow back water treatment and (2) develop a production process to make these technologies commercially viable.
ABS Materials Inc., Wooster, Ohio 44691-9359
The primary commercial and research focus of this project is the treatment of flowback water resulting from gas field hydraulic fracture stimulations. Unconventional natural gas is an important growing domestic energy supply typically found in shale plays. The challenge industry faces is determining what to do with the flow back water. The Energy Information Agency (EIA) projects shale gas natural gas production will continue to grow, reaching 45 percent of the total volume of produced U.S. natural gas by 2035.Thus, advanced methods to treat flow back water are important for developing this substantial domestic energy source.
Flow back water is an amalgamation of dispersed oil, dissolved volatile and semi-volatile organics, organic acids, metal ions, radionuclides, oilfield treatment chemicals, salt, polymers, insoluble material (rock dust, organic species), or any combination of these. However, very little effective technology exists to address dissolved hydrocarbons, slicking agents, and polymers, which can prevent flow back water from being recycled or discharged.
This project examines a novel and innovative solution to treat flow back water dissolved organics by using swelling glass - Osorb®, which is an engineered organosilica material with high porosity. Osorb® functions as nanomechanical sponge since the porous matrix rapidly swells up to eight times its dried volume upon exposure to non-polar liquids. Osorb® does not swell in water, but is highly effective at removing a wide range of free or dissolved organics from water, including polar species (such as alcohols and carboxylic acids) and non-polar species (such as toluene, benzene, naphthalene, nonane, octane, and 90 percent of naturally occurring organic acids). The goal is to engineer Osorb-based materials into systems that will reduce flow back fluid clean-up costs, effectively clean flow back water streams, and create purified water that can be safely discharged to the environment. Recovered hydrocarbon products can be sold or used as fuel to power the purification system.
Successful development of the Osorb-based materials to remove hydrocarbons and organic process chemicals would benefit the treatment of flow back water and produced water in the following ways:
- Significantly reduce water storage and disposal costs.
- The portable treatment unit would reduce off-site water hauling and associated costs.
- Water can be recycled for fracturing operations or returned as agricultural water in arid regions.
- Modification of the base Osorb® formulation may allow for selective removal of metal and/or radionuclide contaminants from Marcellus Shale flow back and produced waters.
ABS Materials has completed all Phase I objectives. ABS Materials, in conjunction with three global oil service companies, designed and built a trailer-mounted, 3600 gallon per hour (gal/hr.) flow back water purification system for field use. One major oil services company, with scientific leadership present, was contracted to conduct a full pilot test in the field using produced water from the Clinton Formation (Ohio) in July 2010 and March 2011. Total petroleum hydrocarbon (TPH) levels were reduced from 227 mg/L to 0.1 mg/L during testing. TPH is a more stringent measurement than oil and grease, indicating the treated water was well below the discharge threshold of 29 mg/L. This test successfully demonstrated the effectiveness of Osorb® in a large system.
ABS Materials constructed PWU 1.5, a 65 gal/min fully automated treatment system mounted on a 53 ft. drop-deck trailer, and conducted successful wet testing in June 2012 with fresh water only. Wet testing with the addition of Osorb and the recovery of Osorb from the fresh water was successfully completed in August 2012. The recipient conducted a pivot based on the project costs of running the PWU 1.5 system and the changing value proposition for onsite treating of flowback water vs. sending it to a disposal well. A pilot unit (VOC Capture Unit) capable of a 1 bbl./min flow rate was designed and built based on a replaceable cartridge design. The VOC Capture unit is being used on contaminated industrial waste and the lessons learned are being utilized to improve both the pilot unit design and provide a means to evaluate Osorb regeneration concepts. Industrial wastewater was used as a substitute for produced water in these field trials. The system is modular in design allowing for easy scale up to higher bbl./min flow rates. The replaceable cartridge design for the pilot system virtually eliminated the loss of Osorb during capture and regeneration processes. The two main cost drivers for using Osorb technology are the base cost and costs associated with regeneration. The project has focused significant effort on reducing the cost basis for Osorb through increased manufacturing efficiencies, alternative raw materials utilization, and an increase in the acceptable particle size range for hydrocarbon capture. A second equally important focus was on the regeneration process. Replacing the initial solvent wash, heated-vacuum process is still underway. The use of supercritical carbon dioxide (SC-CO2) was evaluated and determined to be feasible, even with surface water-wet Osorb. The capital costs for even a small SC-CO2 sized integrated system for the 60 gpm pilot unit are approximately $500,000. Therefore, ABS is evaluating other suitable but less capital-intensive regeneration methodologies.
ABS designed, fabricated, and is currently testing a combined solvent wash plus low-pressure steam follow-on treatment all-in-one system. A combined (solvent plus steam) regeneration of Osorb (5.0 kg) that captured mixed-phenols and BETX (benzene, ethylbenzene, toluene, and xylenes) from a Gulf of Mexico offshore platform reduced contamination levels from 12,000 ppm to <200 ppm in 50 minutes.
Osorb® modified with organic groups that bind metals ions was developed and shown to selectively bind certain cations. ABS Materials completed bench-scale testing of forms of Osorb® that co-extract radionuclides (ex. 235U, 212Pb, 228Ac). In addition, ABS Materials has begun evaluating formulations that can be used to harvest rare earth cations from produced water. Variants of the Osorb technology for binding metal ions have led to several proposals to capture copper and nickel from effluent streams to achieve compliance with environmental discharge limits.
Current Status (June 2014)
The cost basis for producing the base Osorb material continues to be driven down through improved manufacturing processes, reduced labor, distillation and re-use of solvents, and improved particle grinding and recovery efficiencies. These combined improvements have resulted in achievement of 75% of the targeted cost reduction goal. Additional cost reduction activities continue with 100% of the cost reduction goal expected to be met over the next year.
Osorb was stress tested under the combined (solvent plus low-pressure steam) regeneration process for 30-cycles. The goal was to determine how robust Osorb would be when subjected to repeated regeneration events. Osorb that experienced more than 12-combined regeneration cycles exhibited a 20% loss in capture capacity. No further loss in capture efficiency was observed. ABS Materials currently recommends that our clients use no more than 12-combined regeneration cycles. A major client on an offshore natural gas platform is evaluating this regeneration process (with a 300 kg charge of Osorb). Initial results indicated that Osorb performed as expected and had 20% more capacity vs. a granular activated carbon-based system. Low-pressure steam regeneration is scheduled to be performed at an on-shore location.
ABS Materials initiated an additional regeneration approach to utilize liquid butane as the regeneration solvent plus heat process. The approach is to pass liquid butane through corn oil-laden Osorb to remove the oil via a gas reclamation pump. Pilot-scale testing has demonstrated 75 percent corn oil removal, which is comparable to SC-CO2 regeneration. A small-scale butane extraction system is being built to further explore this approach with the goal of replacing butane with liquefied petroleum gas in follow-on designs.
Project Start: June 19, 2010
Project End: August 14, 2014
DOE Contribution: $1,082,434
Performer Contribution: $175,000
NETL – John Terneus (firstname.lastname@example.org or 304-285-4254)
Absorbent Materials Corporation (ABS Materials) – Stephen Jolly (email@example.com) or 330-234-7999)
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