4. wesp round table presentation october 2010

8/11/2019 4. WESP Round Table Presentation October 2010

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Operating Experience of Wet

Electrostatic PrecipitatorsSam Kumar & Adel Mansour

Babcock & Wilcox Company, USA

Round Table Sulfuric Acid Conference

Puerto Varas, Chile

October 17-20, 2010


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Typical Acid Product Specifications

Hg PPM 0.5

As PPM 0.5

Se PPM 0.5

Pb PPM 1.0

As+Cu+Ni+Cd PPM 1.0


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Venturi Scrubber Performance Alone

Is Not Enough

To achieve low levels of arsenic emissions

highly efficient wet ESPs will be required

High level of fine particulate control is needed

High level of sulfuric acid mist control is needed

Maximum practical particulate control ahead

of wet ESPs ( in the dry ESPs and venturis ) will

reduce maintenance requirements of WESPs


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B&Ws Wet ESP Technology Milestones

2010 Babcock & Wilcox PowerGeneration Group, Inc. All rights reserved.

.4

The B&W Company offers WESP products based on the technology, experience and

know-how of Western Precipitation, Joy, Fluid Ionics, and FLS.

B&W licensed all of FLS WESP technology for all applications

on a world-wide basis

B&W acquired the pollution control business of Joy Environmental, which

included that of Joy Western and Western Precipitation

1907

1995

2004

2003

B&W entered into a contract with FLS to supply WESPs for supply of (2)

power plant capturing sulfuric acid mist ESPs for a power plant complex

totaling 1,050 MW of generation

Western Precipitation installs their first wet precipitator on a smelter in Selby

California


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Several B&W wet ESP reference plants

in the Americas

Groupo Mexico, SPCC, Ilo, Peru

CODELCO El Teniente, Chile

Groupo Mexico, Mexicana DeCobre, Mexico Cominco Trail, BC, Canada

Xstrata Horn, Canada

Xstrata CEZinc, Canada Xstrata Falconbridge, Canada


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Lead wet ESP Codelco EL Teniente

Casing bottom and middle section installation


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Codelco EL Teniente

ChileInstallation of lead tubesheet


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Grupo Mexico-Southern Peru Copper ILO


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Grupo Mexico-Southern Peru Copper, ILO

Lower High Voltage Discharge Electrode Frame


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Wet ESP Tube/Rigid Electrode Design

Old Cells

New Cells


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WESP Corona Current Profiles

Acid Plant Inlet Outlet Electrode

Field* Field*

#1 15 23 Star wire#2 7.5 20 Star Wire

#3 15 15 Star Wire

#4 50 60 Pipe & Spike#5 60 - Pipe & Spike

* Corona current density in mA/1000 ft2


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Benefits Of Alloy Design


.13

All alloy materials

Excellent electrical conductor

Continuous irrigation system not required

Robust construction permits periodic high pressure washing

Greatly reduces risk of damage by fire


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Hex Tube WESP Design Collector DesignMore Capacity in Same Footprint


.14

More efficient

footprint with the

hex tube design

More collection surface using double sided collection

Replacement of round tube design with higher capacity alloy hex tube

B&W WESPs


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Rigid Discharge Electrodes in Alloy Design

Electrode DesignHigh Reliability


.15

Self-supporting

rigid discharge

electrodes

Rigid pipe and nail construction = higher reliability

Higher corona producing discharge electrodes = superior WESP

performance

Self supporting arrangement, no insulators in the gas stream


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Hex Tube Design and Project Advantage


.17

Modular designFits existing footprint

Flexibility in size (surface area)

Maintenance accessibility


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Transporting Collector Assemblies


.19


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Lifting the Collector Assembly


.20


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Installing the WESP Collector

Assembly


.21


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Alloy WESP Units Replacement

for Lead Acid Mist Units


.22

Customer A B1 B2 C

Application Pet-Coke

Calciner #3, #1& #2

Metallurgical

Sulfuric Acid Plant

#1

Metallurgical

Sulfuric Acid

Plant #2

Spent Acid Regeneration

WESP unit Cell #4, #1 (in

parallel) & #6

2 cells

(in parallel)

4 cells

(2+2 in series)

2 cells ( in series)

Foot print 16 ft x 17.5 ft

(each)

13.5 ft x 15.5 ft

(each)

13.5 ft x 15.5 ft

(each)

15 ft x 16 ft (each)

New WESP

No. of tubes

238 & 248 hex(each)

17 ft long tubes

150 hex (each)

17 ft long tubes

150 hex (each)

17 ft long tubes

248 hex (each)

15 ft long tubes

New WESP

collecting area

11,650 sq. ft.

(each)

7,395 sq. ft. (each) 7,395 sq. ft.

(each)

10,711 sq. ft. (each)

Old WESPNo. of tubes

98 lead tubes

(each)

(in parallel)

3 cells x 126 lead

tubes

(in parallel)

6 cells x 120 lead

tubes (3+3 in

series)

2 cells x 164 lead tubes

(in parallel)

Old WESP

collecting area

4,360 sq. ft.

(each)

4,950 sq. ft. each 4,712 sq. ft.

each

4,126 sq. ft. each

In Operation 1999, 2007 &

2008

2000 2000 2006


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Alloy WESP Replacement Example For

Lead Acid Mist Units


.23

Customer B1 - Acid Plant

6 Old Lead WESP Modules with

Lead Tubes and Steel Shell

4 New HEX WESP Modules 150 Tubes

replaced 6 old Lead WESP modules


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Alloy Materials Suitability Curve


.24

Approximate Service Limits for Stainless Steels and Nickel-Base Alloys in Flue Gas Condensates and Acid Brines

at Moderate Temperatures (140176 F)


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Corrosion Study

Confirm Material SelectionCorrosion rack will include alloy coupons of 904L,

6%Mo, 654SMO, C276, C22, etc.

Test rack to be installed in operating unitsat the inlet and outlet sides

Test rack to be removed and analyzed after

test period

A key planning tool to switch to highperforming , economical alloy WESP design



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Design and Maintenance Issues with

wet ESPs

Uniform Flow Distribution improves performance

Well aligned electrodes maximize power toWESP to maximize performance Poorly aligned electrodes lower power input

Increased sparking can lead to wire breakage and de-energizing of precipitator stage affecting performance

Insulators need to be kept warm and dry Premature tracking leads to low power

Damaged insulators can short the entire precipitatorstage

Purge air systems need periodic maintenance


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Perforated Plate Gas Flow Distributor

& Lower Flush Header


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Misalignment of Discharge Wire

limits operating power


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Insulators Must Be Clean & Dry


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Frequent Inspection & Maintenance is important

Acid and dust buildup on HV insulators

limits operating power


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V/I Curves: Indicative of Performance

and Maintenance Issues

Normal curve. After corona is formed,

current increases with increasing voltage.

0

200

400

600

800

1000

1200

0 10 20 30 40 50 60

Voltage, kV

Current,ma

1


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V/I Curves (2)

Indicates resistance path to ground. May be due tocracked insulator or loose wire touching tube wall.

0

200

400

600

800

1000

1200

0 10 20 30 40 50 60

Voltage, kV

Current,ma

12


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V/I Curves (3)

Indicates severe misalignment betweenemitting electrodes and collecting plates.

0

200

400

600

800

1000

1200

0 10 20 30 40 50 60

Voltage, kV

Current,ma

12

3*


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V/I Curves (4)

Acts like increased radius of emittingelectrode (heavy deposits on rounded star

wire edges).

0

200

400

600

800

1000

1200

0 10 20 30 40 50 60

Voltage, kV

Current,ma

12

3*

*4


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V/I Curves (5)

Indicates corona quenching due to severe spacecharge. Little increase in current with increasing

voltage because corona is not formed.

0

200

400

600

800

1000

1200

0 10 20 30 40 50 60

Voltage, kV

Cur

rent,ma

12

3* 5

*4


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Conclusions

Dedicated maintenance can result in highly

improved reliability and availability of wet

ESPs

Alloy designs have been introduced to

replace lead WESPs

Designs show much noticeable improvements in

both performance and reliability

Better footprint efficiency can help retrofit and

expansion options considerably


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Thank You !! Local Babcock & Wilcox Contact in Chile

Technagent

Raul A. Sigren O.

Gerente General

Presidente Emazuriz 3262

Casilla 25Santiago 35, CHILE

[email protected]

[email protected]
mailto:[email protected]:[email protected]

4. wesp round table presentation october 2010

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