Super-charged Pulsed Jet Combustor for Salt-water Separation in Remediating Hydo Fracturing Brines

Open Access
Author:
Cash, Colin Christopher
Graduate Program:
Environmental Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
February 20, 2015
Committee Members:
  • Fred Scott Cannon, Thesis Advisor
  • Robert Carl Voigt, Thesis Advisor
  • William D Burgos, Thesis Advisor
Keywords:
  • hydraulic fracturing
  • brine
  • pulse combustor
  • pulse jet
  • natural gas
Abstract:
Historically, petroleum production processes (e.g., oil, natural gas, and coal extraction) have produced briny wastewater streams, with total dissolved solids concentrations near saturation. Presently, the unprecedented production of natural gas from deep, low-permeability, sedimentary rock formations within the continental United States (particularly the northeast) has brought heightened scrutiny to oil and gas well stimulation (i.e., through the hydraulic fracturing process). Of particular environmental concern is the collection, transportation, storage and ultimate fate of the hypersaline wastewaters from natural gas wells. Natural gas production wells that have been stimulated by hydraulic fracturing release nearly half of the three to five million gallons of fluid used in the process. This mildly saline water is called flowback. Although flowback lasts for only a few weeks, for the remainder of its lifetime the well will produce a more saline wastewater called produced brine. The chemical composition of these wastewaters is complicated, as they contain significant concentrations of organic molecules and radioactive isotopes. Because the solids content can be over 20% the total solution mass, traditional wet chemistry and conventional desalination techniques (e.g., reverse osmosis, thermal distillation, etc.) are ineffective for remediating these wastewaters. This has led to deep well reinjection to become the sole disposal option for these wastewaters. In this thesis, an unconventional remediation technique for these hypersaline brines is investigated. Since the main contaminant in flowback and produced brines is a high concentration of dissolved solids, the author employed surrogate hypersaline brines that were artificially created and experimentally remediated by using a proprietary super-charged pulsed jet combustor technology. In this research, the super-charged pulsed jet combustor was investigated as a potential technology for separating the salt from water, in solutions near saturation (with respect to sodium chloride). Pulsating combustors are known for their exceptional fuel efficiency, as well as their ability to produce powerfully turbulent exhaust fields, which enhance convective drying rates. In this thesis, the experimental, pilot-scale system used was capable of processing brines with total dissolved solids concentrations above 200,000 mg/L – meeting a current technology gap in the field of flowback and produced brine treatment. It demonstrated the ability to evaporate nearly one-third the solvent mass of a nearly 0.5 gallons per minute (114 liters per hour) hypersaline brine flow, while retaining almost all the mass of processed solids within a five foot (1.52 meter) diameter round basin located beneath the tailpipe end of the combustor.