Evaluation of Electrodialysis for the Desalinization of Shale Gas Flowback Water
This project was a portion of a larger investigation into the quantity and quality of the flowback water and process alternatives available to 1) maximize the reuse of recovered water, 2) minimize the volume of deep well disposal, and 3) reduce the cost and environmental impact of disposal of flowback water. This report represents the first laboratory published investigation of the potential of electrodialysis as an alternative desalination process for flowback water, culminating in the treatment of field water from the Marcellus and from the Barnett.
Document Type
Report
Report Type
Topical Report
Report Period
March 2012
Author(s)
Blaine F. Severin, Ph.D., P.E.; Tom Hayes, Ph.D.
Corporate Source
Gas Technology Institute (GTI)
Sponsor
Research Partnership to Secure Energy for America (RPSEA)
Evaluation of Electrodialysis for the Desalinization of Shale Gas Flowback Water
Barnett and Appalachian Shale Water Management and Reuse Technologies
RPSEA Report No: 08122-05.12
Electrodialysis is an electrochemically driven membrane separation technology. A pair of electrode cells generates a potential across a number of cell pairs designed to segregate ions into a diluate stream and a concentrate stream. This process has historically been successfully used for water containing several thousand mg/l (roughly parts per million) TDS down to several hundred mg/l. The range of TDS expected in flowback water is several tens of thousands mg/l, and includes ranges of divalent cations in the thousands of mg/l.
Eight full electrodialysis runs were performed with pure sodium chloride. Seven runs were dedicated to understanding the effect of calcium to the electrodialysis process. An additional seven runs addressed the added complexity of treating water in the presence of calcium, barium, magnesium, and iron. Eleven tests were performed with waters from the Marcellus and the Barnett.
During the test period, a number of problems were encountered. Literature suggests that these problems historically impeded development of electrodialysis for complex solutions of concentrated divalent cations. As these problems were encountered in this project, they were addressed by making a number of improvements to the electrodialysis process specific to this laboratory unit. Some of these improvements represent potentially scalable means for cost savings. Others of these improvements represent critical changes needed to keep the electrodialysis unit operational.
