Novel Treatment Technologies for Desalination and Selective Ion Removal

Transcription

1 Novel Treatment Technologies for Desalination and Selective Ion Removal Lucy Mar Camacho, Ph.D. Department of Environmental Engineering Texas A&M University - Kingsville Eagle Ford Center for Research, Education and Outreach City of Cotulla, Texas November 15, 2013

2 Outline Background The Fact The need The opportunity Novel Desalination Technologies Electrodialysis/Electrodialysis metathesis (ED/EDM) Membrane distillation (MD)

3 Background

4 The Fact Water pumping, treatment, and distribution Energy production and generation

5 The Need Growing competition for freshwater supplies has motivated interest in use of saline groundwater for water supply. USGS, Delineating and assessing saline groundwater water resources, 2009.

6 Saline-Water Withdrawals Texas Withdrawals Fresh Saline Total Million gallons per day 23,600 3,130 26,730 USGS, Delineating and assessing saline groundwater water resources, 2009.

7 The Opportunity Natural Gas Production Unconventional Sources Shale Gas Flowback from Hydraulic Fracturing Formation Water

8 Water use in US Shale Gas Plays Average water use for drilling and hydraulic fracturing a shale gas well (Million gallons ) Texas Oklahoma 3.0 Marcellus shale Initial volume returned as flowback (%) 8-15% 30-70% TDS concentrations (mg/l) 8, ,000 U.S. Energy Information Administration based on data from various published studies; May 9, Shaffer et al.; Environ. Sci. Technol. 2013, 47,

9 The Challenge Growing restrictions on produced water disposal Strong incentives for produced water desalination for external reuse Higher water quality than for internal reuse within the shale gas industry

10 Desalination Challenges for High- Salinity Water Reuse Water Corrosion and scale products. Calcium sulfate. Barium sulfate. Strontium sulfate Organic fouling. Dissolved organics. Suspended organics Naturally occurring radioactive. Barium and radium isotopes TDS. Hardness. Heavy metals Energy Thermal separation process. Technically feasible. Economically relevant Alternatives for high-salinity produced water Municipal wastewater treatment Industrial wastewater treatment Underground injection wells Reuse for subsequent hydraulic fracturing operation (90%) (Internal Use).

11 Novel Desalination Technologies

12 Thermal and Membrane Separation Technologies Mechanical Vapor Compression (MVC) Forward Osmosis (FO) Membrane Distillation (MD) Electrodialysis Metathesis (EDM) Efficiency Achieve stringent permeate TDS concentration limits for external reuse. Modular nature Facilitate on-site treatment at shale gas well sites. Energy requirements Competitive compared to conventional thermal technologies kw-h/m kw-h/m kw-h/m 3 (with energy recovery) Less than 10 kw-h/m 3 (based on NaCl purity) Shaffer et al.; Environ. Sci. Technol. 2013, 47, CIDS, 2013

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14 Electrodialysis

15 EDM Process Mixed Sodium Mixed Chloride Mixed Sodium Mixed Chloride Mixed Sodium C A C A C A C A C A C1 D1 C2 D2 C1 D1 C2 D2 C1 Anode (+) SO 4 = Cl - Na + Mg +2 Ca +2 Na + Mg +2 Ca +2 Cl - SO 4 = Na + Mg 2+ Ca 2+ Cl - SO 4 = (-) Cathode Na 2 SO 4 Feed: NaCl Feed: NaCl Na 2 SO 4 High-salinity water High-salinity water

16 EDM Process H 2 O H 2 O Feed + EDM - Mixed Mixed NaCl Feed Na Cl C1 C2 D2 D1 E-Rinse (Na 2 SO 4 )

17 EDM Experimental Electrodes EDM Operating Conditions Number of repeating cells (quads) 5 Compartments per cell 4 Number of membranes 20 Anode: Pt/Ti Cathode: Stainless steel Membrane type Anion-, cation-exchange Active membrane area per cell (m 2 ) 0.02 Current (Amp) (constant) 1.56 Applied voltage (Volts) 8-12 Pressure (psi) 3.0 EDM system Average flow rate (gpm) D1: 0.45; D2: 0.45 C1: 0.60; C2: 0.50 E-Rinse: >1.3

18 EDM - Experimental C1 Mixed Sodium Stream

19 EDM - Experimental C2 Mixed Chloride Stream

20 Voltage (Volts) EDM - Experimental 14 Effect of D2 impurities on cell voltage Time (hours) Pure 1350 mg/l SO4 563 mg/l Ca SO4, Ca, Mg mixture High recovery mixture

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22 MD - Principle Water vapor pressure difference Heat transfer By diffusion Heat transfer by conduction

23 Membrane Distillation - Process

24 MD - Configurations

25 MD Modules & Membranes Flat Sheet Spiral Wound Hollow Fiber

26 MD - Experimental Combined water outfall sample Parameter As received After treatment with AGMD After treatment with DCMD Ca (mg/l) Mg (mg/l) below D.L Hardness as CaCO3 (mg/l) TDS (mg/l) TOC (mg/l) Iron (mg/l) silica (mg/l) ph

27 MD - Experimental Selenium unit outfall sample Parameter As received After treatment with AGMD After treatment with DCMD Ca (mg/l) Mg (mg/l) Hardness as CaCO3 (mg/l) TDS (mg/l) TOC (mg/l) Iron (mg/l) silica (mg/l) ph

28 MD Heavy Metals Removal S. Yarlagadda, S. Gnaneswar, L.M. Camacho. J. Hazardous Materials, 2011, 192, Camacho, L.M. et al., Water, 2013, 5,

29 MD - Water-Energy Nexus Energy alternatively obtained from waste Heat. DCMD module

30 Thank you!!