Events Calendar

09 Jun
PhD Final Defense - Ritesh Dinkar Pawar
Event Type

Defenses

Topic

Research

Target Audience

Faculty, Graduate Students, Postdocs

University Unit
Department of Chemical and Petroleum Engineering
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PhD Final Defense - Ritesh Dinkar Pawar

This is a past event.

Title: Fundamentals and Scale-up of Membrane Distillation for Treating Produced Waters from Unconventional Oil and Gas Reservoirs

 

Abstract: Hydraulic fracturing of shale oil and gas reservoirs poses significant environmental concerns related to water management. This process generates a large volume of produced water with high total dissolved solids (TDS). Membrane distillation (MD) can be a cost-effective solution for treating produced water, especially when waste heat is utilized. The distributed nature and varying characteristics of produced waters in shale plays create an opportunity for deploying modular MD systems. The objective of this study is to evaluate the feasibility of using membrane distillation for treating produced water from unconventional reservoirs with emphasis on fundamental developments and scale-up of the process.

 

Lab-scale tests were conducted on commercially available membranes, which showed excellent salt rejection but continuous increase in permeate conductivity due to the passage of volatile compounds and certain organic substances. Detailed organics analysis revealed passage of some organics like nonylphenol ethoxylates (NPEOs) and octylphenol ethoxylates (OPEOs) from feed to permeate but did not lead to wetting of the membranes. In an attempt to better understand the interaction between non-ionic surfactants and hydrophobic membrane, lab-scale studies were conducted with non-ionic surfactants like NPEOs and OPEOs with varying ethoxylate chain length and concentration. Alternative surfactants like linear alcohol ethoxylates (LAEs), branched secondary alcohol ethoxylates (BAEs), alkyl polyglycosides (APGs) were also examined due to concerns surrounding NPEOs in hydraulic fracturing. The study's results shed light on the impact of traditional surfactants on MD and identify alternative surfactants that can support hydraulic fracturing, address environmental concerns, and enable membrane distillation.

 

To upscale the lab-scale findings, pilot-scale studies were conducted using an air gap MD system to treat produced water from the Permian Basin. Filtration-only pre-treatment resulted in precipitation of certain salts (SrSO4, NaCl, and Fe) when their solubility limits were exceeded. However, chemical pre-treatment involving pH adjustment, aeration, and barite precipitation allowed successful steady-state operation of the pilot system for 5 days, recovering 50% of the produced water as high-quality permeate. The pilot-scale studies were extended to test produced water from different shale gas plays across the United States, including the Bakken formation, Eagle Ford Basin, and Marcellus play, considering varying salinity levels and pre-treatment methods. The pilot plant performance was evaluated to determine the cost of treating produced water, and the obtained permeate was assessed for beneficial reuse.

 

Drawing on the comprehensive understanding gained from lab and pilot-scale studies, this study offers insights into the potential use of MD as a cost-effective treatment option for high salinity wastewaters, yielding good quality water.

 

Chair:

Dr. Radisav D. Vidic

Department of Chemical and Petroleum Engineering and Department of Civil and Environmental Engineering, University of Pittsburgh

 

Committee: 

Dr. Vikas Khanna

Department of Chemical and Petroleum Engineering and Department of Civil and Environmental Engineering, University of Pittsburgh

 

Dr. Lei Li

Department of Chemical and Petroleum Engineering, University of Pittsburgh

 

Dr. Carla Ng

Department of Civil and Environmental Engineering, University of Pittsburgh

Dial-In Information

Zoom link: https://pitt.zoom.us/j/92786104341

Meeting ID: 927 8610 4341

Passcode: PWMD

Friday, June 9 at 10:00 a.m. to 12:00 p.m.

Benedum Hall, 702
3700 O'Hara Street, Pittsburgh, PA 15261

PhD Final Defense - Ritesh Dinkar Pawar

Title: Fundamentals and Scale-up of Membrane Distillation for Treating Produced Waters from Unconventional Oil and Gas Reservoirs

 

Abstract: Hydraulic fracturing of shale oil and gas reservoirs poses significant environmental concerns related to water management. This process generates a large volume of produced water with high total dissolved solids (TDS). Membrane distillation (MD) can be a cost-effective solution for treating produced water, especially when waste heat is utilized. The distributed nature and varying characteristics of produced waters in shale plays create an opportunity for deploying modular MD systems. The objective of this study is to evaluate the feasibility of using membrane distillation for treating produced water from unconventional reservoirs with emphasis on fundamental developments and scale-up of the process.

 

Lab-scale tests were conducted on commercially available membranes, which showed excellent salt rejection but continuous increase in permeate conductivity due to the passage of volatile compounds and certain organic substances. Detailed organics analysis revealed passage of some organics like nonylphenol ethoxylates (NPEOs) and octylphenol ethoxylates (OPEOs) from feed to permeate but did not lead to wetting of the membranes. In an attempt to better understand the interaction between non-ionic surfactants and hydrophobic membrane, lab-scale studies were conducted with non-ionic surfactants like NPEOs and OPEOs with varying ethoxylate chain length and concentration. Alternative surfactants like linear alcohol ethoxylates (LAEs), branched secondary alcohol ethoxylates (BAEs), alkyl polyglycosides (APGs) were also examined due to concerns surrounding NPEOs in hydraulic fracturing. The study's results shed light on the impact of traditional surfactants on MD and identify alternative surfactants that can support hydraulic fracturing, address environmental concerns, and enable membrane distillation.

 

To upscale the lab-scale findings, pilot-scale studies were conducted using an air gap MD system to treat produced water from the Permian Basin. Filtration-only pre-treatment resulted in precipitation of certain salts (SrSO4, NaCl, and Fe) when their solubility limits were exceeded. However, chemical pre-treatment involving pH adjustment, aeration, and barite precipitation allowed successful steady-state operation of the pilot system for 5 days, recovering 50% of the produced water as high-quality permeate. The pilot-scale studies were extended to test produced water from different shale gas plays across the United States, including the Bakken formation, Eagle Ford Basin, and Marcellus play, considering varying salinity levels and pre-treatment methods. The pilot plant performance was evaluated to determine the cost of treating produced water, and the obtained permeate was assessed for beneficial reuse.

 

Drawing on the comprehensive understanding gained from lab and pilot-scale studies, this study offers insights into the potential use of MD as a cost-effective treatment option for high salinity wastewaters, yielding good quality water.

 

Chair:

Dr. Radisav D. Vidic

Department of Chemical and Petroleum Engineering and Department of Civil and Environmental Engineering, University of Pittsburgh

 

Committee: 

Dr. Vikas Khanna

Department of Chemical and Petroleum Engineering and Department of Civil and Environmental Engineering, University of Pittsburgh

 

Dr. Lei Li

Department of Chemical and Petroleum Engineering, University of Pittsburgh

 

Dr. Carla Ng

Department of Civil and Environmental Engineering, University of Pittsburgh

Dial-In Information

Zoom link: https://pitt.zoom.us/j/92786104341

Meeting ID: 927 8610 4341

Passcode: PWMD

Friday, June 9 at 10:00 a.m. to 12:00 p.m.

Benedum Hall, 702
3700 O'Hara Street, Pittsburgh, PA 15261

Event Type

Defenses

Topic

Research

Target Audience

Faculty, Graduate Students, Postdocs

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