10122-07

Primary Performer
GE Global Research

Additional Participants
GE Water & Process Technologies
Endicott Interconnect Technologies, Inc.

Abstract
Horizontal drilling and slickwater hydrofracturing have given the Marcellus shale the potential to become the second largest natural gas field in the world. One limitation to developing the Marcellus is the cost of disposing hydrofracturing flowback and produced water (collectively, “frac” water), which, on average, is about twice as saline as seawater. Much Marcellus frac water also contains significant levels of naturally occurring radioactive materials (NORM), particularly radium, as well as barium, which is toxic. Besides recycle and reuse, a significant volume of Pennsylvania Marcellus frac water is trucked into Ohio, at a cost of up to $15 per barrel (bbl), for disposal by deep-well injection.

The overall project objective is to develop a cost-effective process to recover distilled water and a salable salt product from Marcellus frac water. The first goal is to develop a pretreatment process that removes NORM, particularly 226Ra, from frac water and enables disposal of a NORM-concentrate in an environmentally responsible manner. The second goal is to develop a brine concentrator based on membrane distillation (MD) that is suitable for Marcellus frac water desalination and is significantly less capital cost-intensive than currently available evaporators. The emphasis of both objectives is that pretreatment and brine concentration may be accomplished in mobile facilities. It is anticipated that crystallization will occur in a central treatment facility. Successful execution of this project will reduce the cost and environmental impact of hydrofracturing.

In this project, GE Global Research (GEGR) will develop and validate at the pilot scale, two technologies to economically recover 90-95% of Marcellus frac water as clean water and a salable salt: NORM removal pretreatment and MD brine concentration (Figure 1). Work is in progress (under RPSEA project 08122-36) to identify frac water NORM removal pretreatment technologies. Prior to the start of the proposed project, GEGR will downselect a single NORM removal pretreatment process for further development. The proposed project will also leverage GEGR’s experience with membrane distillation, which has the potential to significantly reduce capital and operating costs for frac water concentration. In order to reduce frac water transportation costs and exploit the economy of scale for crystallizer and salt handling equipment, the team envisions mobile pretreatment and MD concentration units combined with a central, stationary crystallizer and salt handling facility.

During the first year of this 2-year project, GEGR will conduct lab and pre-pilot studies on several Marcellus frac waters to establish a pretreatment process for NORM removal and MD equipment protection. GEGR will also establish and validate a MD module design through a combination of modeling, lab-scale tests, and pre-pilot validations. During the second year, GEGR will conduct pilot validations of Marcellus frac water pretreatment and water recovery by MD.

Principal Investigators: James Silva

Project Duration: 2 years