|Swellable Organosilica Materials to Clean Produced Water
||Last Reviewed 1/15/2015
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 flowback 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 flowback fluid clean-up costs, effectively clean flowback 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 flowback 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.) flowback water purification system for field use. One major oil services company, with scientific leadership present, 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 projected 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. ABS is evaluating other suitable regeneration methodologies.
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 percent of the targeted cost reduction goal. Additional cost reduction activities continue with 100 percent of the cost reduction goal expected to be met over the next year.
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.
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. 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.
The liquid butane extractor was redesigned to improve cleaning effectiveness and perform regeneration of the contaminate-laden Osorb. The new design removed +99 percent of corn oil from water-wet Osorb. The project team determined that other low boiling gases (LPG [liquefied petroleum gas] and refrigerant R134a) are suitable for use in the liquid-gas extractor for regeneration of Osorb.
Current Status (January 2015)
The Phase IIB Award was granted. Modified scope and new project title; “Removal of Organics and Phenol from Refinery Water using Swellable Organosilica”. The goal is to economically treat “hard to treat” wastewater streams that adversely affect the refinery's wastewater infrastructure. One problematic stream contains phenols, which inhibit the biological activity of the water treatment plant when dosed in high concentrations. Another problematic stream is jet-fuel wash water that contains a high loading of naphthenic acids that cause the water treatment plant to experience a high biological oxygen demand.
The first task is to define the kinetics of phenol bio-digestion for use in a Modular Osorb Biodigestion system. A biotic (factors that affect biology) assay is underway. Three sources of bacteria, two levels of macro-nutrients, and four levels of phenol were studied in batch reactors held at room temperature. The levels of macro-nutrients studied had insignificant influence on biodigestion; high levels of bacterial source material are more effective than low levels. An abiotic (non-biological components) assay is concurrently underway (two levels of phenol, two levels of exposure, three particle size ranges, and seven types of modified Osorb.) Both sulfur-modified and regular Osorb have the highest absorption at high phenol levels. Sulfur, iron-oxide, and regular Osorb have equally high absorption of phenol at low phenol levels. Both biotic and abiotic assays will continue.
The potential for removing organics from jet-fuel wash water was investigated using a simple naphthenic acid (cyclo-pentyl-propionic acid [CPPA]). Regular Osorb was dosed with 25wt percent CPPA and then treated with liquefied butane (LB). The LB removed +99 percent of the CPPA from the dry Osorb and the neat CPPA was recovered. The potential exists for recovered naphthenic acids to be sent to a hydrotreater for conversion to suitable jet-fuel feed stock materials.
Discussions with a refinery development partner to identify the higher value proposition, phenol removal from water stream or recovery of naphthenic acids from jet-wash water are proceeding. Shipment of refinery waters of both types are being arranged to support continued investigation.
Project Start: June 19, 2010
Project End: August 14, 2016
DOE Contribution: $2,081,935
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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