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Clean Air Technologies CIBO-2003 Electrostatic Precipitation Technology Dry ESPs vs. Wet ESPs CIBO 2003 Electrostatic Precipitation For Multi-Pollutant Control By Dr. Isaac Ray Clean Air Technologies

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Page 1: Electrostatic Precipitation For Electrostatic

Clean Air Technologies

CIBO-2003

Electrostatic Precipitation Technology

Dry ESPs vs. Wet ESPs

CIBO 2003

Electrostatic PrecipitationFor

Multi-Pollutant ControlBy

Dr. Isaac Ray

Clean Air Technologies

Page 2: Electrostatic Precipitation For Electrostatic

Dry ESP vs. Wet ESP Technology• ESP History • Particle Size & Opacity• Primary Functions • Benefits of ESPs • ESP Process• Dry-Wet ESP Comparison • Design Parameters• ESP Configurations• Application-Test Results • New ESP Technologies

Corona Discharge

Page 3: Electrostatic Precipitation For Electrostatic

History of ESP Technology

• Century Old Technology• Developed by Dr. Cottrell in 1907• Originally Applied to Sulfuric Acid Mist• 1925 Power Boiler Industry adopts Dry ESP• Dry ESPs are Foundation of Modern APC• New MACT Regulations are requiring Wet ESPs

Page 4: Electrostatic Precipitation For Electrostatic

PM2.5

PM10

PM1

Particle Size

Page 5: Electrostatic Precipitation For Electrostatic

OPACITY LIGHT EXTENSION

0.5 MICRON PARTICLES ARE THE WORST ACTORS

Page 6: Electrostatic Precipitation For Electrostatic

As Particle Size DecreasesElectrostatic Forces Increase

Page 7: Electrostatic Precipitation For Electrostatic

Primary Functions

• Dry ESP– Course Particulate Removal– Fly Ash -2-10 micron

• Wet ESP– Final “Polishing” Device – PM2.5– Acid Mist -H2SO4 – Metals (including Hg)– Opacity Reduction

Rebuilt Dry ESP at Duke Powercourtesy of Southern Environmental

Page 8: Electrostatic Precipitation For Electrostatic

Benefits of ESP Technology

• Low-Pressure Drop– Low Energy Usage

• Proven Performance - 99% Removal– PM10- Dry ESPs– PM2.5/Acid Mists/Metals- Wet ESPs

• Reliable Control Devices– Dry ESPs- Mechanical Cleaning– Wet ESPs-Washing – Wet ESPs

Page 9: Electrostatic Precipitation For Electrostatic

Ionizing ElectrodeGAS

MOLECULESIONIZED

CORONADISCHARGE

CURRENT METER

HIGH VOLTAGETRANSFORMER

mA

1. Charging •Gas ions formed by high voltage corona discharge•Particles charged by bombardment of gaseous ions

2. Collection •Ions transport particles to collector•Particle charge given up to collector

3. Cleaning •Dry ESP-

•Particles collect on collection surface •Particles accumulate •Plate cleaned by rapping or sonic horns

•Wet ESP•Particle trapped in liquid film•Not on the collection plate•Liquid film continuously cleans surface•No accumulation on collection surface

CLEANING OF THE COLLECTION SURFACE IS THE KEY DIFFERENCE

ALLOWS FOR MUCH HIGHER POWER AND NO RE-ENTRAINMENT

Electrostatic Precipitation Process

PARTICLEENTERS PARTICLE

COLLECTED

PARTICLECHARGED

PARTICLEIRRIGATEDFROM WESP

Dry ESPCollection Surface

CHARGE RETURNS TO TRANSFORMER

Wet ESPCollection Surface

Liquid SlurryParticles

Page 10: Electrostatic Precipitation For Electrostatic

ISSUE DRY ESP WET ESPPM10 Removal YES NOCarbon Steel MOC YES NOCleaning via Rapping/Sonic Horns YES NOBack Corona YES NORe-Entrainment YES NOUnsaturated Flue Gas YES YES*Saturated Flue Gas NO YESPM2.5 Removal NO YESPM1 Removal NO YESSO3 Removal NO YESToxic Metal Removal NO YESMercury Removal NO YES

Dry-Wet ESP Comparison

Page 11: Electrostatic Precipitation For Electrostatic

Design Parameters

PARAMETER UNITS DRY WETESP ESP

PRECIPITATION RATE FT/SEC 0.05 - 1.00 0.15 - 2.00SCA FT2/MCFM 50 - 1000 50 - 500CORONA POWER WATTS/MCFM 50 - 500 500 - 3000GAS VELOCITY FT/SEC 3 - 8 3 - 12+?

Page 12: Electrostatic Precipitation For Electrostatic

ESP Configurations

• Tubular TypeVertical Down Flow-wetVertical Up-flow -wet

• Plate TypeHorizontal Flow-dry/wetVertical Up-flow -wet

For a given volume, a tubular ESP has twice the collection area as a plate ESP. Therefore, a tubular WESP can operate at twice the velocity of a plate type ESP, resulting in a smaller footprint for a given efficiency. .

Page 13: Electrostatic Precipitation For Electrostatic

Make-up

Coal Supply

Flue Gas

Heated Air

Ambient AirDry Bottom Ash Dry Fly Ash Wet FGD Solids

Sluice Water

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Boiler

Air Preheater

Dry ESP

SCR

-

+

Wet FGD

WaterTreatment

WESP

+

High Sulfur Coal Boiler Application with Dry and Wet ESPs

Saturated Flue Gas with FGD

Page 14: Electrostatic Precipitation For Electrostatic

WESP Pilot PlantWESP Pilot Unit

Coal-Fired Power Plant Pilot WESP- 2400 MW plant- >50% opacity-State requires < 20%

-Rated 5,000 CFM -Tubular WESP-Slip-Stream after FGD-PM2.5 & SO3-Mercury Testing

Page 15: Electrostatic Precipitation For Electrostatic

Minimum Power

Maximum Power

View Through Obs. TubeObservation Tube-Opacity

Medium Power

Page 16: Electrostatic Precipitation For Electrostatic

Coal Fired Utility Pilot Test-Designed for 90% Removal at 5,000 cfm in One Field-Tested at 8,000 cfm - 76%-79% Removal in one field- Modified to 2 Fields - achieved 92%-96% removal- Mercury-Limited Testing-Oxidized removed similar to PM2.5

Summary of Pilot Wet ESP Test Results- Bruce Mansfield Plant –2001-2002Mercury

PM2.5 SO3 Mist Tests Particulate Oxidized ElementalAverage of all TestsTest Series Sep-01 Nov-01 Sep-01 Nov-01 Sept –01 Sept -01 Sept –01Airflow-acfm 8394 8235 8394 8235 8000 8000 15000Velocity –ft./sec.

10 10 10 10

# of fields 1 2 1 2 1 1 1Power Levels 100% 100% 100% 100% 100% 100% 100%

ug/dscm ug/dscm ug/dscmInlet 0.0292 0.0506 11.475 10.01 0.011 0.689 6.245Outlet 0.0063 0.002 2.7 0.85 0.004 0.158 3.474

Removal % 79% 96% 76% 92% 64% 77% 44%

Page 17: Electrostatic Precipitation For Electrostatic

Nov-01 InletPM2.5-116mg/m3

SO3-10.1 ppm

Nov-01 OutletPM2.5- 5 mg/m3

SO3- 0.85 ppm

Iso-Opacity Chart of Test ResultsIso-Opacity Curve

Opacity is a function of both PM2.5 & SO3 mist. An Iso-Opacity chart predicts opacity from a given PM2.5 and SO3 concentration

Page 18: Electrostatic Precipitation For Electrostatic

Kyanite Mining-Virginia-Ore Roasting-cyclone/scrubber/WESP system

Pollutant Units Inlet Outlet Removal %SO2 Ppm 3580.07 21.4 99.4ACID MIST(H2SO4)

gr /dscf 0.228 0.0159 93.0

PM2.5 gr /dscf 1.6 0.006 99.6NOx Ppm 41.1 21.5 47.7CO Ppm 640.63 581.6 9.2CONDENSED,INORGANIC

Gr/dscf 0.13102 0.0143 89

CONDENSED,ORGANIC

Gr/dscf 0.14148 0.01573 90

THC Ppm ascarbon

225.3 85.5 62

Opacity >50% <5%

Page 19: Electrostatic Precipitation For Electrostatic

Pollutant Units Test Runs MACTLimits

Removal%

Particulate Gr/dscf, 7%O2 0.0024-0.0030 0.015 99.94

HCL/Cl2 ppmdv, 2.96-4.84 77 99.95

Chromium Ug/dscm 39.7-42.8 97 99.97

Lead Ug/dscm 3.59-3.85 240 99.95

Mercury Ug/dscm 1.82-1.98 130 79%

Dioxin/furan Ng TEQ/dscm 0 0131-0 0892 0 4 N/D

Eastman Chemical- Hazardous Waste Combustors- Test Results-EPA MACT - Simultaneous worst case - All pollutants

Page 20: Electrostatic Precipitation For Electrostatic

Make-up

Plate RecycleDry Fly Ash

Blow dow n

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Dry ESP

Coal Supply

Flue Gas

Heated Air

Ambient AirDry Bottom Ash

Sluice Water

+Boiler

APH

SCR

Recycle

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WESP

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+

Low Sulfur Coal Boiler Application Hybrid Dry-Wet ESP

Unsaturated Flue Gas with No FGD

Page 21: Electrostatic Precipitation For Electrostatic

Substitute WetLast Field

20 º F To 50 º FAbove Saturation

All Dry: 0.2lb/MBtu

Dry/Wet: 0.03lb/MBtu

Hybrid Dry/Wet ESP

EPRI Test ResultsParticulate matter: 95% Sulfur dioxide: 20%Hydrogen chloride: 35%Hydrogen fluoride: 45%Mercury - to be piloted

Page 22: Electrostatic Precipitation For Electrostatic

Conclusions• ESP Technology is Well-Established & Proven• Dry ESPs -Used for Course Particulate (PM10)• Up to 99% Efficiency• Unsaturated Flue Gas • Horizontal Plate Configuration• Cleaning via Mechanical Rapping or Horns

• Wet ESPs- Used for PM2.5, H2SO4 mist & Metals• Final “polishing “ of the flue gas • Up to 99% Efficiency• Saturated & Unsaturated Flue Gas• Tubular & Plate Configuration

• Cleaning via Washing of Collection Surface