Novas tecnologias de precipitadores eletrostáticos_Charles Hayes_Southern Environmental

New Electrostatic Precipitator Technologies in

the Pulp & Paper Industry

Charles Hayes

Regional Sales Director

SOUTHERNenvironmental ,INC

.

Pensacola, Florida

Introduction

New technologies which may be of particular

interest in the Brazilian Pulp & Paper Industry

• Customized discharge electrodes to reduce outlet emissions

• High frequency SMPS to replace conventional T/R sets

• New techniques for better gas distribution

• Top-rapped ESP design – advantages compared to “European” design

• ESP Conversion – Tumbling Hammer to Top-rapped design – a case study

Techniques to improve performance

in ESP Rebuilds/Upgrades

Your logo • Customized RDEs

• Increase Electrical Sectionalization

• Increase Rapping Sectionalization

• Enhance ESP Flow Distribution by Modeling

• Enhance Hopper & Anti-Sneakage Baffling

• Advanced SMPS Power Supplies

• Convert Tumbling Hammer to Top-Rapped design

ELEX Rigid Discharge Electrode

• Rigid –Unbreakable – Electrode Design

• Variable Emitter Point Settings

• Variable Emitter Tab settings

• Low Corona Onset Voltage

• Uniform Current Distribution to Plates

• Plate Spacing Between 250 and 400 mm

ELEX Rigid Discharge Electrode

• Customized throughout ESP fields

• More Points – for high dust load in Inlet Fields

• Superior in overcoming space charge effects

• Optimum Particulate Charging

• Eliminates lower frame spit sparking

ELEX RDE Configurations

Aggressive – More

points per meter

Standard – fewer

points per meter

ELEX Rigid Discharge Electrode

(Optimized)

ELEX VRS Pipe & Spike

ELEX vs. Pipe & Spike

Airload V-I Curves

Top-Rapped ESP Internals

Internals showing DE & CE Rappers

Collecting Plate Design

• 1.3 – 1.6 mm thick A-366 Steel

• 445 mm Segments or Opzels

• Cold roll Formed

• Edge Arc-Over Prevention

• Uniform Thermal Movement

Rapping System

• Design Objectives: • To Clean Collecting and Discharge Electrodes

• Minimize Re-entrainment, Stack Puffs, and Back Corona

• Maintenance Needs: • Reliability, Low Maintenance, and Serviceability

• Types: • Electromagnetic, Hammer, and Vibrators

ICAC Gas Distribution Criteria

• 3.2.1 Guaranteed precipitator operating efficiency. Gas flow uniformity becomes

• increasingly important as operating efficiencies approach 100% due to:

• 3.2.1.1 The tendency for the smaller particles to follow the gas flow streamlines more

closely.

• 3.2.1.2 The increased need for almost total suppression of gas bypassing and hopper

sweepage. Thus, the higher the guaranteed operating efficiency of a precipitator, the more

important the optimization of the gas flow.

• 5.1.1 Within the treatment zone near the inlet and outlet faces of the precipitator collection

chamber, the velocity pattern shall have a minimum of 85% of the velocities not more than

1.15 times the average velocity, and 99% of the velocities not more than 1,40 times the

average velocity. Average velocity refers to the mean of all velocity measurements made at

a given face of the precipitator.

• Copied from: Institute of Clean Air Companies – Publication ICAC – EP- 7

CFD of Recovery Boiler ESP

High Frequency Power Supply

Features

• Operating Frequency = 25 kHz compared to 50

to 60 Hz for conventional T/R set energization

• Typically provides 10% increase in secondary

voltage & about a 25–40% increase in secondary

current

• 3-phase input results in higher power factor

• Performance Enhancement Factor (w’/w) for

moderate to low resistivity applications

• Similar installed cost as conventional T/R sets

SMPS offer Big Benefits

• More efficient – up to 30% more power into the ESP

• Combines T/R, controller, Reactor and ground switch in one package

• Higher power factor (.94 vs .63) means lower power consumed per kw of power to ESP

• Easier to install – no AVC room

• Field serviceable – plug-in, plug-out components

• Smaller & lighter than Traditional T/R’s

• Less/limited bus duct required

[ms]

[kV]

0

20

40

60

80

Conventional T/R

SMPS

Time (ms)

ESP

Current

[mA]

SMPS wave form vs conventional T/R

SMPS - No Ripple

New High Frequency Power Supply

70 kV@1000mA SMPS Smaller & lighter

SMPS INSTALLATIONS

• Results and Benefits

• More power into ESP

• Lower emissions

• Less line power consumed

Electromagnetic Rapping Advantages

• External Location Allows Online Servicing

• Control Sequencing, Timing, Rapping Forces

• Same Rapping System on CEs & Des – Copper coil (10 kg)

– 27 joules capacity

– Variable intensity

– 10 kg Piston with Stainless Steel Tip

Common Parts for All Rapping Systems

Modern Rapper Controls

• Microprocessor Control

• Password protected

• Variable duration, lift, and sequence

• Anti-coincidence Grouping

• Rapper failure alarms

• Remote display option with fiber optics

• Multiple rapper programs

• DCS compatible

Top-Rapped

vrs Tumbling Hammer Design vrs Tumbling Hammer Design

Top Rapped

Tumbling Hammer

• Two- point suspension

• MIGI Rappers

• Rappers out of gas stream

• Variable rapping frequency

• Variable rapping intensity

• Short (1 m – 4 m) field length

• 0.3 m – 0.5 m between-field

length

• Typically penthouse design

• Typically single CE plate

• Heavy duty, reliable DE’s

• Four point suspension

• Tumbling hammers

• Rappers in gas stream

• Variable rapping frequency

• Fixed rapping intensity

• Large (2 m – 5.5 m) fields

• 1.5 m – 5.5 m between-field

space required

• Insulator Compartments

• Panel plate assembly

• DE’s subject to breakage &

tension loss

Top-Rapped

vrs Tumbling Hammer Design

• Multiple CE plates per rapper

• Typical CE rapping ratio -

< 138 m2 per rapper

• Customizable DE emitter

points

• Straightforward assy of DE

• Bottom frame simplifies

alignment

• More shop fabrication –

lower field erection cost

Typical CE rapping ratio - Typical CE rapping ratio - Typical CE rapping ratio - Typical CE rapping ratio -

• One CE plate per rapper

• Rapping ratio could be

higher w/long field

• Limited customization

possible

• Frame assembly is field-

labor intensive

• No bottom frame

• Overall field erection is labor

intensive

Tumbling Hammer TOP RAPPED

Top-Rapped

vrs Tumbling Hammer Design

• Typically smaller ESP for a

given gas flow

• Greater cost effective

electrical sectionalization

available

• Minimal internal maintenance

• Routine maintenance can be

performed on line

• Typically better performance

for a given SCA (f value)

• Typically more cost-effective

for a given gas volume

• Typically larger ESP for a

given gas flow

• Minimal sectionalization;

larger TR sets

• Internals are maintenance

intensive

• Most routine maintenance

performed off line Typically

Inferior performance for a

given SCA

• Typically less cost-effective

for a given gas volume

Tumbling Hammer TOP RAPPED

Improving ESP Performance

in a

SHORT TIME

a

Case History

The rebuilt Unit uses the same casing as the

existing ESP, but with internals converted from

tumbling hammer to top-rapped design. The

other design changes are:

Old New

3 Mechanical fields 6 mechanical fields

250 mm CE spacing 400 mm CE spacing

Conventional TR’s SMPS

Opacity 15-20% Opacity <<10%

Converting a Tumbling Hammer ESP to

Top-rapped Design - a case history

Pre Outage work to pre-assemble the roof

extension and penthouse

Penthouse

Ring/Roof

Girder

This shows that the unit was originally a tumbling

hammer design

Day 4

Starting to remove the old collecting electrodes

Day 7

Internals removal complete

Day 8

Lifting the pre-assembled ring/roof girder

Day 8

Lowering the pre-assembled

ring/roof girder onto the prepared flange

Day 12

Lifting a bundle of new Collecting electrodes

Day 12

Installing the new Collecting electrodes

Day 20

Starting to install the hot roof

Day 23

Cold roof installation complete

Day 24

Installing the CE rapper sleeves & shafts

Day 25

Rappers, T/R sets installed, LV wiring started

Day 27

Nighttime lifting of weather enclosure

Day 28

Weather enclosure in place - finish LV wiring

Day 29

Rebuild

complete

Ready for

Startup

Startup

Successful

After

4 week

outage

Contact Information

Charles Hayes

Regional Sales Director

SOUTHERNenvironmental,INC.

6690 West Nine Mile Road

Pensacola, Florida 32526

850-941-3001

chayes@sei-group.com

Renato Greco

New Technologies Development Manager

ENFIL

Renato.greco@enfil.com