2005/07/20 - PDF Free Download

2005/07/20 E-mail: mbchang@ncuen.ncu.edu.tw

plasma At the beginning of this talk, let s be sure what plasma is. 2

Plasma Non-Thermal Plasma (NTP) 3

PLASMA IS EVERYWHERE. PLASMA TECHNOLOGY Environmental Application 4

http://images.spaceref.com/news/2005/webimage110504.l.jpg 5

Initiation Cosmic Rays e - O 2, N 2 + e - e - O 2 + O 2 + e - e - Electron impact ionization (require E t ) Secondary electron emission e - e - e - e - e - e - e - e - e - e - e - e - e - e - e - Electron avalanche etc. 6

e + pollutant products e + O 2 O( 1 D) + O + e e + H 2 O OH + H + e e + M M + + 2e O, O( 1 D), OH, M + + pollutant products O( 1 D) + H 2 O OH + OH O + O 2 + M O 3 + M O 3 + pollutant products 7

The gas stream contains 7% CO 2, 8% O 2, 6% H 2 O, 400 ppm CO, 260 ppm NO, 133 ppm H 2, 0-1100 ppm C 3 H 6 and N 2 as balanced gas.

(Thermal Plasmas) ( ) (Non-Thermal Plasmas, NTP) >> ( ) (Cold Plasmas) 9

etching, cleaning, PECVD, surface modification, plasma polymerization ESP is a well known plasma technology. The mainstream technology used for ozone synthesis. Be suitable for air and wastewater treatments. 10

* COD * (NO x,so 2 ) * (VOCs) * (H 2 S) (CO * 2,CH 4 ) (PFCs) / * (ODS) ( ) (Hg 0 ) # # UV * * / * * # 12

Plasma Reactors 13

1. (electron beam, E-beam) 2. (corona discharge) 3. (dielectric barrier discharge, DBD) 14

(e-beam) 1960 1. X-ray 2. 3. 4. 5. 15

X Y 16

(corona discharge) 1980 (pulsed corona discharge) 2000 NO x SO x 17

(dielectric barrier discharge, DBD) 1900 1980 DBD 19

DBD 1. 1. 2. 2. 1. DBD 2. DBD 1. 2. 20

(a) (b) (c) (d) (e) (f) (a) (b) (c) (d) (e) (f) 21

NO X SO X NO x NO NO 2 NO 2 HNO x NO 2 HNO x NH 3 NH 4 NO 3(s) (ESPBag-House) 23

NO x NO NO, NO2 conc. (ppm) (2). (3~8%) 1.0E+04 1.0E+02 1.0E+00 1.0E-02 (1). NO NO 2 NO>90% NO NO 2 1.0E-04 0 500 1000 1500 2000 Temp. (K ) 24

NO X SO X NOxSOx 1 NH 3 NH 3 25

NO X SO X NOxSOx 2 NTP Hg 0 An integrated air pollution control technology named ECO system is currently in field demonstration testing in a 1-2 MW slipstream unit at FirstEnergy's R.E. Burger Plant since February 2002. It achieves great reductions in four primary air pollutants of concern from coal-fired power plants, specifically 98% reduction of sulfur dioxide (SO 2 ) emissions, 90% of nitrogen oxide (NO x ) emissions, 80-90% of mercury (Hg) emissions, and 95% of fine particulate matter (PM2.5) emissions. http://www.powerspancorp.com/technology/scrubber_overview.shtml 26

Simultaneous Removal of NO/NO /SO from Gas Streams 2 2 by Combined Plasma Scrubbing (CPS) Technology Chang M.B., Lee H.M., Wu F.L., and Lai C.R. "Simultaneous Removal of NO/NO 2 /SO 2 from Gas Streams by Combined Plasma Scrubbing Technology," Journal of Air & Waste Management Association (2004). (accepted for publication)

Illustration of NO x /SO 2 removals with CPS t dry gas streams NO + SO 2 N 2 NO 2 /HNO 3 SO 2 /H 2 SO 4 NO O NO 2 NO O 3 NO 2 O 2 NO OH HNO 2 NO 2 OH HNO 3 NO N N 2 + O Additive Plasmas NO 2 + SO 2 wet gas streams NaS 2 /Na 2 SO 3 Na 2 SO 4 absorbers residuals Scrubber NO 2 NO 2(aq) Exhaust NO 2(aq) + 2Na 2 SO 3(aq) 1/2 N 2 + 2Na 2 SO 4(aq 2 NO 2(aq) Na 2 S N 2 Na 2 SO 4 SO 2 SO 2(aq) SO 2(aq) + Na 2 SO 3(aq) + H 2 O 2 NaHSO 3(aq) HNO 2 HNO 2(aq) HNO 3 HNO 3(aq) HSO 3 HSO 3(aq) H 2 SO 4 H 2 SO 4(aq)

Treatment of diesel exhaust with CPS. Exhaust High-Voltage ac Power Supply Power Meter A Oscilloscope V A side flow of 3.5 lpm was pumped into the CPS system. Pump Rotameter Compositions of diesel exhaust were: 17.6% O 2, 64 ppm NO, 18 ppm NO 2, 385 ppm CO, 11 ppm SO 2, and 1.9% H 2 O (g). DBD Exhaust Gas Analyzers FT-IR Testo-350 Wet Scrubbing Combined Plasma Scrubbing (CPS) Diesel Engine The diesel generator tested was a four-cylinder engine with a compression ratio of 16 and electric power output of 37.5 kw.

Treatment of diesel exhaust with CPS. ependence of NO, NO 2, NO x and SO 2 concentrations on applied voltage DBDs only CPS system 100 100 Concentrations (ppmv). 80 60 40 20 NOx NO NO2 HNOx SO2 Concentrations (ppmv). 80 60 40 20 NOx NO NO2 HNOx SO2 0 0 5 10 15 20 Applied voltage (kv) 0 0 5 10 15 20 Applied voltage (kv) EXPERIMENT: The tested diesel generator (Perkins 4.236 Series) was a four-cylinder engine with a compression ratio of 16 and electric power output of 37.5 kw. Typical compositions of its exhaust were 17.6% O 2, 64 ppm NO, 18 ppm NO 2, 385 ppm CO, 11 ppm SO 2 and 1.9% H 2 O (g). A side flow of 3.5 lpm was pumped into the CPS system.

A (1) NH 3 ) B (2) NH 3 ) C (1) D (2) NH 3 ) NH 3 ) smaller space needed. 31

Destruction of VOCs and PFCs with Nonthermal Plasma Technologies Lee, H.M. and Chang, M.B., "Destruction of VOCs via Silent Discharge Plasmas," Chemical Engineering and Technology, 21(12), 987-989 (1998). Lee H.M. and Chang M.B., "Gas-Phase Removal of Acetaldehyde via Packed-Bed Dielectric Barrier Discharge Reactor," Plasma Chemistry and Plasma Processing, 21(3), 329-343 (2001). Lee H.M. and Chang M.B., "Removal of Gaseous Acetaldehyde via a Silent Discharge Reactor Packed with Al 2 O 3 Beads," Journal of Advanced Oxidation Technologies, 6(1), 48-54 (2003). Lee H.M. and Chang M.B. "Abatement of Gas-phase p-xylene via Dielectric Barrier Discharges," Plasma Chemistry and Plasma Processing, 23(3), 541-558 (2003).

VOCs & PFCs Global warming PFCs, CH 4 Ozone depletion CFCs, Halons Building & Material Human health 34

VOCs & PFCs Main Mechanisms for VOC Removals VOCs + (e, ion, O, OH, HO 2, O 3 ) CO 2 + H 2 O Main Mechanisms for PFC Removals PFCs + (e, ion) C-F fragments C-F fragments + (O, OH, HO 2, O 3 ) CO 2 + HF/F 2 + H 2 O C-F fragments + C-F fragments PFCs 35

VOCs VOCs + (e, ion, O, OH, HO 2, O 3 ) CO 2 + H 2 O (g) 1. CO and/or HCs 1. E/N 2. NO x and/or PMs 2. E/N 3. 3. 36

Effect of Additives O 2 H 2 O 100 100 Removal Efficiency (%) 80 60 40 20 24 kv 22 kv 20 kv 18 kv 16 kv 14 kv Removal Efficiency (%) 80 60 40 20 18 kv 16 kv 13 kv 0 0 5 10 15 20 Oxygen (%) 0 0.0 0.5 1.0 1.5 2.0 2.5 H 2 O concentration (%) as streams contained 500 ppmv p-xylene, selected xygen concentrations and balanced N 2 with a total as flow rate of 0.5 slpm. Gas streams contained 500 ppmv p-xylene and selected water vapor concentrations in N 2 with a total gas flow rate of 1.0 slpm. Lee H.M. and Chang M.B. "Abatement of Gas-phase p-xylene via Dielectric Barrier Discharges," Plasma Chemistry and Plasma Processing, 23(3), 541-558 (2003). 37

Removal Efficiency (%). 100 80 60 40 20 0 10 12 14 16 18 20 22 Applied Voltage (kv) 100 80 60 Removal Efficiency (%). 40 20 0 10 12 14 16 18 20 22 Applied Voltage (kv) 5 mm Al 2 O 3 5 mm glass non-packed 5 mm Al 2 O 3 3 mm Al 2 O 3 2 mm Al 2 O 3 Enhancing E e by Packing Dielectric Materials within DBD Conditions: [CH 3 CHO]=1000 ppmv [O 2 ]=5% N 2 as carrier gas T = 303 K Q 1.0 splm Lee H.M. and Chang M.B., "Removal of Gaseous Acetaldehyde via a Silent Discharge Reactor Packed with Al 2 O 3 Beads," Journal of Advanced Oxidation Technologies, 6(1), 48-54 (2003). 38

. VOCs 1000000 100000 10000 1000 100 10 1 0.01 0 0.1 0 1 10 100 1000 10000 100000 1000000 0 39

(Gas) [] (Atmospheric Lifetime) (GWP 100 ) CO 2 50-200 1 CH 4 12±3 21 N 2 O 120 310 HFC-23 (CHF 3 ) 264 11,700 HFC-32 5.6 650 HFC-125 32.6 2,800 HFC-134 14.6 1,300 HFC-143 48.3 3,800 PFCs HFC-152 1.5 140 HFC-227 36.5 2,900 HFC-236 209 6,300 HFC-4310 17.1 1,300 CF 4 50,000 6,500 C 2 F 6 10,000 9,200 C 4 F 10 2,600 7,000 C 6 F 14 3,200 7,400 SF 6 3,200 23,900 GHG Greenhouse Gases 41

PFCs PFCs + (e, ion) C-F fragments C-F fragments + (O, OH, HO 2, O 3 ) CO 2 + HF/F 2 + H 2 O C-F fragments + C-F fragments PFCs 1. 2. 3. 1. E/NInert gases 2. Additives 3. Combined Plasma Catalysis, CPC 42

PFCs (Point-of-Use, POU) (End-of-Pipe) Deposition! 43

Enhancing PFC Abatement by Catalysts --- Combined Plasma Catalysis (CPC) 44

Combined Plasma Catalysis (CPC) influent dielectric outer electrode teflon inner electrode packed materials effluent Combined Plasma Catalysis, CPC Cu/Zn Catalyst Chemical Compositions (wt.%) CuO 64 ZnO 24 Al 2 O 3 10 MgO 2 45

CF 4 Abatement by Catalysis, DBD, and CPC 70 CF4 Abatement (%). 60 50 40 30 20 10 0 Catalysis DBD CPC only only The inlet gas streams contain 300 ppm CF 4, 40% Ar, 20% O 2, and N 2 as balance. The gas flow rate is kept at 600 sccm. For CPC and DBD, applied voltage and frequency are 15 kv and 240 Hz, respectively. hang M.B. and Lee H.M. "Abatement of Perfluorocarbons with Combined Plasma Catalysis in Atmospheric-Pressure Environment," Catalysis Today, 89, 109-115, (200 46

Abatement of PFCs with Combined Plasma Catalysis (CPC) 100 PFC Abatement (%). 80 60 40 20 0 NF3 3 SF6 6 C2F6 2 F 6 CF4 4 0 100 200 300 Applied Frequency (Hz) The inlet gas streams contain 300 ppm PFCs, 40% Ar, 20% O 2, and balanced N 2. The gas flow rate is kept at 600 sccm. The applied voltage is kept at 15 kv. hang M.B. and Lee H.M. "Abatement of Perfluorocarbons with Combined Plasma Catalysis in Atmospheric-Pressure Environment," Catalysis Today, 89, 109-115, (200 47

Products Selectivity for PFC Abatements by DBD and CPC CF 4 C 2 F 6 100 DBD CPC (a) 100 DBD CPC (b) 80 80 Selectivity (%). 60 40 20 Selectivity (%). 60 40 20 0 CO2 2 CO COF2 2 CF4 4 0 CO2 2 CO COF2 2 CF4 4 The inlet gas streams contain 300 ppm CF 4 or C 2 F 6, 40% Ar, 20% O 2, and balanced N 2. The gas flow rate is kept at 600 sccm. The applied voltage and frequency are kept at 21 kv and 60 Hz, respectively. hang M.B. and Lee H.M. "Abatement of Perfluorocarbons with Combined Plasma Catalysis in Atmospheric-Pressure Environment," Catalysis Today, 89, 109-115, (200 48

Dioxins the highest toxicant Introduction: Dioxins the highest toxicant dioxin formation potential in flue gas NTPs <200 o C dioxin formation temperature window 250~450 o C T ( o C) Close to the typical operation temperature of SCR. Catalysis working at low T might avoid dioxin formation. 50

Gas-phase Dioxin Control Technologies Traditional Fast quenching DSI + FF Adsorption bed Catalysis Novel Non-thermal plasmas UV/TiO 2 Low-temp. catalysis Inhibitors How about a technology combining them together? 51

Introduction: Combined Plasma Catalysis (CPC) Plasmas Catalysts High Efficiency Low Temp. CPC High Selectivity Middle Temp. high efficiency, high selectivity, low temperature... 52 high efficiency, high selectivity, low temperature...

CPC Reactors influent dielectric outer electrode teflon inner electrode influent dielectric outer electrode teflon inner electrode effluent Dielectric Barrier Discharge, DBD packed materials effluent Combined Plasma Catalysis, CPC TiO 2 Catalyst Chemical Compositons (wt.%) Al 2 O 3 88 TiO 2 12 Cu/Zn Catalyst Chemical Compositions (wt.%) CuO 64 ZnO 24 Al 2 O 3 10 MgO 2 53

Process / Sampling Location Demonstration Pilot Test Position Stack sampling point SCR inlet S li i 54

Experimental Conditions the flue gas characteristics the CPC characteristics Sampling Location between ESP & SCR Temperature () 100±3 CO 2 (%) 5.1 O 2 (%) 15.5 H 2 O (g) (%) 12.9 Particulate matters (mg/nm 3 ) 19.7 Diameter of Inner Electrode Dielectric Thickness Dielectric Material Discharge Gap Discharge Length Gas Temp. Gas Flow Rate Mass of Weight Voltage Frequency 0.6 cm 0.2 cm quartz 1 cm 20 cm 100 0 C 10 LPM Cu/Zn 15 g TiO 2 25 g 15 kv 60 Hz 55

100 80 60 40 20 0 PCDD/F Congener Removal TiO2 catalyst Cu/Zn catalyst 56 1,2,3,7,8-PeCDD 1,2,3,4,7,8-HxCDD 1,2,3,6,7,8-HxCDD 1,2,3,7,8,9-HxCDD 1,2,3,4,6,7,8-HpCDD OCDD 2,3,7,8-TCDF 1,2,3,7,8-PeCDF 2,3,4,7,8-PeCDF 1,2,3,4,7,8,-HxCDF 1,2,3,6,7,8-HxCDF 1,2,3,7,8,9-HxCDF 2,3,4,6,7,8-HxCDF 1,2,3,4,6,7,8-HpCDF 1,2,3,4,7,8,9-HpCDF 2,3,7,8-TCDD OCDF Removal Efficiency (%)

Comparison of Dioxin Removals with CPC and Catalysis PCDDs 2,3,7,8-TeCDD 1 1,2,3,7,8-PeCDD 0.5 1,2,3,4,7,8-HxCDD 0.1 1,2,3,6,7,8-HxCDD 0.1 1,2,3,7,8,9-HxCDD 0.1 1,2,3,4,6,7,8-HpCDD 0.01 OCDD 0.001 PCDFs 2,3,7,8-TeCDF 0.1 1,2,3,7,8-PeCDF 0.05 2,3,4,7,8-PeCDF 0.5 1,2,3,4,7,8-HxCDF 0.1 1,2,3,6,7,8-HxCDF 0.1 1,2,3,7,8,9-HxCDF 0.1 2,3,4,6,7,8-HxCDF 0.1 1,2,3,4,6,7,8-HpCDF 0.01 1,2,3,4,7,8,9-HpCDF 0.01 OCDF 0.001 PCDD/F removal efficiency (%) 100 80 60 40 20 0 100 80 60 40 20 0 CPC Catalysis 2,3,7,8-TeCDD 1,2,3,7,8-PeCDD 1,2,3,4,7,8-HxCDD 1,2,3,6,7,8-HxCDD 1,2,3,7,8,9-HxCDD,2,3,4,6,7,8-HpCDD OCDD 2,3,7,8-TeCDF 1,2,3,7,8-PeCDF 2,3,4,7,8-PeCDF 1,2,3,4,7,8-HxCDF 1,2,3,6,7,8-HxCDF 1,2,3,7,8,9-HxCDF 2,3,4,6,7,8-HxCDF CPC (TiO2 catalyst) CPC (Cu/Zn catalyst) Catalysis (Ti/V/W) 57 1,2,3,4,6,7,8-HpCDF 1,2,3,4,7,8,9-HpCDF OCDF

Comparison of Dioxin Removals with CPC and Catalysis Trend for Catalysis Removal Efficiency Trend for CPC Trend for Dioxin TEFs lowly chloridated highly chloridated Dioxin Congeners 58

PCB Congener Removal 100 80 60 40 20 CPC (TiO2 catalyst) CPC (Cu/Zn catalyst) 0 59 3,3,4,4 -TCB # 77 3,4,4,5-TCB # 81 2,3,3,4,4 -PeCB # 105 2,3,4,4,5-PeCB # 114 2,3,4,4,5-PeCB # 118 2,3,4,4,5-PeCB # 123 3,3,4,4,5-PeCB # 126 2,3,3,4,4,5-HxCB # 156 2,3,3,4,4,5 -HxCB # 157 3,3,4,4,5,5 -HxCB # 169 2,3,4,4,5,5 -HxCB # 167 2,3,3,4,4,5,5 -HpCB # 189 Removal Efficiency (%) Removal Efficiency (%)

Summary of Simultaneous Removal of Dioxins & PCBs 100 De-PCDD/Fs De-PCBs Removal Efficiency (%) 90 80 > 90% can be achieved!!! CPC (TiO2 catalyst) CPC (Cu/Zn catalyst) 60

SO 2 /NO x Electron Beam (EB) 62

E-beam Results of Industrial Pilot Plants 63

( 1998) 64

( 1999) (Mok et al., 1999) NH 3 HCs +DCHV -DCHV (Corona (EP) Discharge) De-SOx > 90% NOx 65

SO 2 /NO x --Korea 66

SO 2 /NO x --Korea 67

SO 2 /NO x --Korea Without C 2 H 4 With C 2 H 4 200 ppm 68

--ECO 69

--ECO http://www.powerspancorp.com/technology/scrubber_overview.shtml 70

--ECO 71

--ECO 72

NO 2 HC N 2 CO 2 NOHC NO 2 HC NO NO 2 HC HC + HC NO 2 + HC N 2 + CO 2 + H 2 O (g) 74

(conti.) (CPC) / Combined Plasma Catalysis 75

de-nox ( ) Item Value Unit Configuration Conversion (%) NO 260 ppm Plasma 26 CO 400 ppm Plasma+Cu-ZSM 5 H 2 133 ppm Plasma+"A" 50 Ar 1 % Plasma+"A"+Cu-ZSM 46 O 2 8 % CO 2 7 % C 3 H 6 1575 ppm C 3 H 8 525 ppm H 2 O 7 % N 2 balance Temperature 180 Flow Rate 2 slpm Specific Energy 30 J/L DBD test device of Ford Motor Co. The device consists of a pair of alumina plates, 18 mm wide by 90 mm long. Gap = 1.3 mm. Catalyst materials have been coated on cordierite monoliths placed downstream of the plasma device. Two proprietary catalysts are used: Cu-ZSM is a copper zeolite formulation provided by a catalyst supplier. Test piece is 25 mm long by 25 mm diameter. A is a proprietary catalyst formulation developed by the CRADA partners. Two pieces used are 25 mm long by 25 mm diameter. 76

de-nox ( ) Source: SEMATECH, 1997. 77

A lean, low-emission machine Delphi Automotive of Troy, Mich., and Pacific Northwest National Laboratory have teamed to develop a new technology that greatly reduces emissions from lean-burn engines, such as diesels. Their durable, compact and energy-efficient technology can be incorporated into a vehicle s existing exhaust system to break apart and convert environmentally harmful oxides-of-nitrogen (NO x ) and particulate matter in auto emissions, to nitrogen, water and carbon dioxide. Initial tests of this nonthermal plasma (NTP) and selective catalytic reduction (SCR) technology on a diesel engine showed a reduction of NO x by 55% without the need to add hydrocarbons to the exhaust. This technology received the Financial Times Global Automotive Award in late 1999 as a technical development with the greatest potential to improve efficiency, safety, comfort, environmental performance or cost structure of motor vehicles and their associated services. 78

NOxSOx VOCs 79