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Characterization of a dielectric barrier discharge (DBD) for waste gas treatment

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The motivation of this project was to enhance the removal of pollutants in waste gas streams from primarily biological sources like poultry farms or food industry which have a high load of odorous gases and methane.

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Characterization of a dielectric barrier discharge (DBD) for waste gas treatment

  1. 1. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Characterization of a dielectric barrier discharge (DBD) for waste gas treatment Examiner: Prof. Dr. rer. Nat. Thomas Hirth Supervisor: Dr. -Ing Andreas Schulz Institute of Interfacial Process Engineering and Plasma Technology (IGVP), Stuttgart MSc Thesis Presentation Devansh Sharma
  2. 2. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Biological sources of air pollution- a major cause for concern  Volatile Organic Compounds (VOCs), odoros gases  Greenhouse Gases (GHGs) like CH4, NxOy  Animal husbandry, food processing, waste and sewage handling  Low loads < 1g C/m3  Up to 9.5 Mt CO2/a reduction potential Sharma, MSc Thesis, 31.10.2014 2 Smog over ShanghaiCommercial pig barn Waste collection in biogas plant http://commons.wikimedia.org/wiki/File: Hog_confinement_barn_interior.jpg http://commons.wikimedia.org/wiki/File: Shanghaiairpollutionsunset.jpg Sharma,WASTEexcursion2013, VergärungsanlageLeonberg
  3. 3. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology State-of-the-art treatment Sharma, MSc Thesis, 31.10.2014 3 Biofilter for biogas plant Thermal catalytic combustion  Bio-filtration  Thermal incineration with/without catalyst  Adsorbtion Sharma,WASTEexcursion2013, VergärungsanlageLeonberg http://users.humboldt.edu/cbeaudry/project_beaudry.html (Oct2014) UrashimaKandChangJ2000 DielectricsandElectricalInsulation,IEEETransactionson7602.
  4. 4. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Structure of the presentation  Introduction  Plasma  Electrical discharges  Dielectric barrier discharge  Chemistry of non-equilibrium plasmas  Experimental setup and modification  Characterization of the discharge  Visual charaterization- variation of operating parameters  Excited species detections with Optical Emission Spectroscopy (OES)  Ozone measurement by absorption spectroscopy  Electrical characterization Sharma, MSc Thesis, 31.10.2014 4
  5. 5. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Plasma Sharma, MSc Thesis, 31.10.2014 5  Quasi-neutral mixture of electrons, ions and neutrals  Thermal plasmas: Te ≈ Ti ≈ Tn  Non-thermal plasmas: Te >> Ti ≈ Tn  Natural and artificial plasmas www.nasa.gov Verhoeff JJ, www.flickr.com/photos/jjverhoef/3567635422 http://www.lucnix.be Alchemist-hp https://commons.wikimedia.org/wiki/File:Glowing_noble_gases.jpg
  6. 6. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Electric discharge in gases Sharma, MSc Thesis, 31.10.2014 6  High electric field between two electrodes – avalanches and streamers form  Electrical breakdown of gas  Gas partially ionized conducting channel – plasma https://en.wikipedia.org/wiki/File: Electric_arc.jpg Chirokov, Pure Appl. Chem., Vol. 77, No. 2, pp. 488, 2005. SchulzA,IGVP Dielectric barrier Anode Cathode
  7. 7. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Dielectric Barrier Discharge (DBD)  Charge deposition on dielectric surface – electric field reversal – discharge stops  On second half cycle, current reversal  Not possible with continuous DC Sharma, MSc Thesis, 31.10.2014 7 KogelschatzUed2000Fundamentalsandapplicationsof dielectricbarrierdischarges Sharma D, IGVP
  8. 8. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Chemistry of non-equilibrium air plasma Sharma, MSc Thesis, 31.10.2014 8  Reactive species needed for destroying pollutants  High energy electrons collide with air molecules and pollutants  Radicals and ions created  Further reactions between excited species  Reactive species like O3 and excited species react with pollutants 𝑒 + 𝑁2 𝑒 + 𝑁2 ∗ 𝑁2 ∗ + 𝑂2 𝑁2 + 2 𝑂 𝑂 + 𝑂2 + 𝑀 𝑂3 + 𝑀
  9. 9. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Experimental setup Sharma, MSc Thesis, 31.10.2014 9
  10. 10. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology DBD stack Sharma, MSc Thesis, 31.10.2014 10 DBD Stack  Approx electrode dimensions: 220 x 220 mm2  34 steel electrodes, 1 mm thick  35 ceramic barrier plates, 5 mm thick  Nose height = 3 mm  Plasma volume = 9.87 liters Electrodes and barrier plate
  11. 11. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Sharma, MSc Thesis, 31.10.2014 11 DBD stack installed in the frame Air inlet from blower Air outlet to absorber Rebuild - avoiding arcing
  12. 12. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Macroscopic analysis of the discharge  Diffuse glow discharge (GD) with column patterns  Filamentary discharge (FD) with big discharge foot  Stable filament formations due to metal surface inhomogeniety  In between FD and GD Sharma, MSc Thesis, 31.10.2014 12
  13. 13. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Current and frequency variation Sharma, MSc Thesis, 31.10.2014 13
  14. 14. Institute of Interfacial Process Engineering and Plasma Technology 14Sharma, MSc Thesis, 31.10.2014
  15. 15. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Frequency variation Sharma, MSc Thesis, 31.10.2014 15 400 Hz 800 Hz
  16. 16. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Air flow variation Sharma, MSc Thesis, 31.10.2014 16 200 m3 h-1 650 m3 h-1 Air in Air in
  17. 17. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Optical Emission Spectroscopy Sharma, MSc Thesis, 31.10.2014 17
  18. 18. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology N2 Second positive system identified Sharma, MSc Thesis, 31.10.2014 18
  19. 19. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Ozone measurements Sharma, MSc Thesis, 31.10.2014 19 0 50 100 150 200 250 0 0,5 1 1,5 2 Ozone(ppm) Power (kW) 300 Hz 385 Hz 460 Hz 540 Hz 630 Hz 735 Hz 780 Hz 800 Hz 0 10 20 30 40 50 0 10 20 30 Ozoneyield(g/kWh) Specific Energy Input (J/L) 385 Hz 300 Hz 460 Hz 540 Hz 630 Hz 735 Hz Max: 45 g O3/kWh According to Beer Lambert Law: O3 (ppm)= 10 6 T 273 P k l log 𝐼 𝑜 𝐼 𝑎
  20. 20. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Voltage - Current characteristics Sharma, MSc Thesis, 31.10.2014 20
  21. 21. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Conclusions  Mixture of Glow Discharge and Filamentous Discharge  Ozone production efficiency – 45 g/kWh  N2 C-B molecular system visible by OES Sharma, MSc Thesis, 31.10.2014 21  Mineral adsorbers would increase contact time  Catalyst to increase reaction rates  Potential of direct/indirect economical remediation of pollutants Outlook
  22. 22. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology THANK YOU FOR YOUR ATTENTION Sharma, MSc Thesis, 31.10.2014 22
  23. 23. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Appendix Sharma, MSc Thesis, 31.10.2014 23 DBD time scales Self repulsion of MDs Chemistry Biofilters Biofilter odor reduction Vibrational temperature O3 absorbance Yield-frequency n-Butanol Evaluating a technique Power supply Equivalent circuit
  24. 24. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology DBD time scales Sharma, MSc Thesis, 31.10.2014 24
  25. 25. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Self repulsion of microdischarges Sharma, MSc Thesis, 31.10.2014 25
  26. 26. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Detailed reactions Sharma, MSc Thesis, 31.10.2014 26 𝑒 + 𝑂2 𝑒 + 𝑂2 𝐵3 Σ 𝑢 − 𝑒 + 𝑂 3 𝑃 + 𝑂 1 𝐷 𝑒 + 𝑁2 𝑒 + 𝑁2 𝐴3 Σ 𝑢 + 𝑁2 𝐴3Σ 𝑢 + + 𝑂2 𝑁2 + 2 𝑂 𝑂 + 𝑂2 + 𝑀 𝑂3 + 𝑀 𝑂 1 𝐷 + 𝐻2 𝑂 2 𝑂𝐻 Machala, J. Phys. D: Appl. Phys. 33 (2000) 3198–3213.
  27. 27. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Biofilter and substrate Sharma, MSc Thesis, 31.10.2014 27 Biofilter substrate Biofilter for biogas plant
  28. 28. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Biofilter odor reduction Sharma, MSc Thesis, 31.10.2014 28
  29. 29. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Vibrational temperature Sharma, MSc Thesis, 31.10.2014 29
  30. 30. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Ozone absorbance Sharma, MSc Thesis, 31.10.2014 30
  31. 31. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Ozone yield vs frequency Sharma, MSc Thesis, 31.10.2014 31
  32. 32. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Removal efficiency of n-butanol vs specific input energy Sharma, MSc Thesis, 31.10.2014 32
  33. 33. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Evaluations are based on  pollutant removal efficiency (%),  Energy efficiency (g/kWh, J/L or kWh/m3)  Pressure drop (kPa/m)  Wanted and unwanted byproducts concentrations (ppm or kg/h) Sharma, MSc Thesis, 31.10.2014 33
  34. 34. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Electrical supply Sharma, MSc Thesis, 31.10.2014 34
  35. 35. www.igvp.uni-stuttgart.de Institute of Interfacial Process Engineering and Plasma Technology Reactor equivalent circuit Sharma, MSc Thesis, 31.10.2014 35

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