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Air Pollution 

Control Systems:

Parts and Service Guide
Welcome to Southern Environmental.

We truly hope that you will find this Parts and Service Guide useful as you work toward 

maintaining and servicing your equipment in this competitive business environment. A 

wise man once told me that there is little reward for hard work unless “smart work” is 

part of the equation.

This guide provides a multitude of information concerning your air pollution control 

equipment, including photographs, descriptions and case histories. SEI is a principal 

supplier of particulate control equipment with extensive experience in Power, Recovery, 

Refinery, Steel and Cement applications.

Given our vertical integration of Engineering, Design, Manufacturing, Construction 

and Service, our philosophy is simple:

 “If we don’t have it, we’ll find it.

 If we can’t find it, we’ll make it.”

SEI has built a solid reputation for retrofitting older equipment to meet today’s emission 

standards. We have extensive experience with equipment built by other manufacturers; 

many of whom no longer service equipment.

Our parts and service team is a group of air pollution control veterans with the single 

mission of keeping your air pollution control systems functioning. No matter the 

complexity of your problem, these men and women can help you with trouble shooting, 

inspections, component replacement, rebuild or upgrade challenges. They understand 

the need for rapid support and timely execution. 

We look forward to working with you,

Southern Environmental, Inc.

Michael R. Johnson

Director
Air Pollution Control Systems: Parts and Service Guide 3

TABLE OF CONTENTS

About SEI ..................................................................................................................4

Purchase Options .....................................................................................................6

Upgrade Services .....................................................................................................7

Inspections ...............................................................................................................8

Repair & Maintenance ..............................................................................................9

Fabrication Facility ..................................................................................................10

ESP Replacement Parts: Wet & Dry .......................................................................11

•	 Discharge Electrodes ....................................................................................12

•	 Collecting Surfaces .......................................................................................17

•	 Electronics & Controls ..................................................................................19

•	 Rappers ...........................................................................................................20

•	 Rapper Components ......................................................................................21

•	 Insulators ........................................................................................................23

•	 Purge Air Systems .........................................................................................25

•	 Access ............................................................................................................27

•	 Dampers & Expansion Joints .......................................................................29

•	 Process Instrumentation ...............................................................................30

•	 Water Recycle System ...................................................................................31

Fabric Filter Replacement Parts .............................................................................33

•	 Bags & Cages .................................................................................................34

•	 Baghouse Parts ..............................................................................................36

•	 Evaporative Cooler Parts ..............................................................................42

•	 Gas Stream Components ..............................................................................43

•	 Reagent Storage ............................................................................................44

Case Histories .......................................................................................................45
4 Southern Environmental, Inc.

ABOUT SEI

Founded in 1973, SEI has served the Power, Recovery, Refinery, Steel, and Cement markets 

heavily for much of these past 40 years. The SEI-Group is comprised of three operating units: 

Southern Environmental, Inc., Southern Erectors, Inc. and Thermal Systems Group. These 

business units are integrated into a tightly knit group who self-perform vertically integrated 

Design and Erect Air Pollution Control Projects.

Operating throughout the Americas, SEI’s focus is on particulate and acid gas control. 

Design, manufacture and construction of Electrostatic Precipitators (ESP) and Fabric Filters 

with sorbent injection systems represents SEI’s core product lines. Over the past 10 years 

the EPA has continued its regulatory tightening of air pollution emission standards, and SEI’s 

design team has responded with the highest quality products in the marketplace to address 

these needs. Specifically, SEI’s S3 electrostatic precipitator design collects particulate and 

added sorbent loads with less specific collecting area than any other ESP available.

With the tightening restrictions on acid gas pollutants, SEI’s fabric filter team in Westerville, Ohio 

specializes in fabric filter systems that are designed around acid gas scrubbing requirements. 

All baghouses are not created equally and the SEI team specializes in custom engineered 

solutions to provide the best fabric filter design to meet a particular customer’s process 

and facility requirements. Media selection, air-to-cloth ratio, gas flow and materials of 

construction all play important roles in final fabric filter design.

Maintenance and service represents a significant portion of SEI’s contribution to our 

customers. SEI has an active replacement parts team that works very closely with 

Serving the Following Industries

Power Generation • Pulp and Paper • Cement • Iron and Steel • Mining

Petro Chemical • Non-Ferrous Metal • Fiberglass
Air Pollution Control Systems: Parts and Service Guide 5

ABOUT SEI

our application engineers to ensure that our customers receive 

the correct replacement component for any given process. In 

addition, our maintenance crews travel throughout the United 

States, providing inspection, repair and replacement services on 

baghouses and both wet and dry electrostatic precipitators. This 

team within the SEI-Group actively supports our customers as 

they plan and budget for their scheduled outage activities. If SEI 

is not an active supplier for your maintenance team, then your 

company is not taking full advantage of a highly skilled resource. 

SEI maintains offices in Pensacola, Florida and Westerville, Ohio. 

The Pensacola campus serves as the corporate headquarters for 

the SEI-Group and houses our fabrication facility, as well as the 

leadership for our ESP engineering and construction management 

teams. The Westerville, Ohio office houses our Fabric Filter 

Specialists, who focus on baghouse design and acid gas scrubbing 

solutions. Both of SEI’s offices interact as a cohesive unit to bring 

vertically integrated Design and Erect solutions to our client base.

 

SEI Projects

SEI Headquaters

Internationally, SEI-Group has performed projects in Antarctica, Argentina, Brazil, 

Canada, China, India, Mexico, Qatar, Russia, Singapore, South Korea, Sweden, 

Taiwan and Thailand.
6 Southern Environmental, Inc.

PURCHASE OPTIONS

EASY PAYMENT OPTIONS 

We strive to offer you more benefits in order 

to assist in keeping your Air Pollution Control 

systems operating at peak efficiency and in 

compliance. One of those ways is to make 

acquiring replacement parts as effortless as 

possible. 

We have the ability to process: Visa, 

American Express and MasterCard. Purchase 

Orders are also accepted.

PURCHASE PARTS ONLINE

Our innovative web based computer program 

makes ordering parts for your ESP or Fabric 

Filter simple, quick and cost effective. SEI’s 

Parts Online System may be beneficial to your 

company in different ways. 

HOW IT WORKS

This system allows our customers to access 

their specific parts information via username 

and password. You can review a listing of your 

spare parts by unit and plant and purchase 

them as you see fit. The purchase can be 

completed using a purchase order or credit 

card. 

When you access the Parts Online System 

you can:

1. View Parts previously purchased

2. View recommended Parts

3. Purchase Parts 

4. View your order status information

BENEFITS

This program is designed specifically for your 

plant and is available to you free of charge. 

Many of our customers have seen this as a 

great benefit for the following reasons:

– Information at your fingertips.

– Helps users to share information, such as 

 order history.

– Makes the process of pricing and 

 ordering straightforward and 

 uncomplicated. 

– Saves time and effort. Time spent for:

• Figuring out part information (part 

 number and description)

• Contacting people within and outside 

 the company

• Receiving quotes

• Placing orders

• Follow-up
Air Pollution Control Systems: Parts and Service Guide 7

UPGRADE SERVICES

Southern Environmental (SEI) can upgrade the 

performance of most fabric filters and precipitators. 

Recent changes to the U.S. emission standards are 

driving all companies to evaluate replacement or 

modification of their existing equipment. SEI is a 

custom solution provider and has devoted the last 

40 years to applying its knowledge base to custom 

engineered upgrade or retrofit solutions. Performance 

upgrades and enhancement may include the following:

Fabric Filter Systems

• Gas distribution modifications

• Filter media change

• Controls upgrade

• Compartmental expansion

• Ash removal system modifications

• Sorbent change – for acid gas scrubbing solutions

Electrostatic Precipitator Systems

• Gas distribution modifications

• Substitution of SEI/ELEX rigid discharge electrodes

• Sectionalization modifications

• Increase collecting electrode spacing

• Rapping system upgrade

• Controls upgrade

• Ash removal system modifications

• Increase collecting area vertically or in the direction 

of gas flow

• Power supply upgrades

• Module expansion – Wet ESP

Each system is unique and requires our engineers to evaluate each unit’s particular 

challenges. There is never a question as to whether we make it better. SEI can always 

make the equipment operate better. The question remains: “What is the best approach 

that meets our customer’s operating, maintenance and economic objectives?”
8 Southern Environmental, Inc.

Periodic inspections are a fundamental aspect of any routine maintenance program. Particulate 

Control Equipment is specialized and requires technicians with a specific experience base to 

identify and troubleshoot problem areas.

SEI employs engineers and technicians experienced with the equipment we manufacture and 

service every day. SEI has built its reputation retrofitting older equipment and also has a working 

knowledge of other manufacturers’ components. 

SEI’s staff is technically proficient at inspecting a variety of equipment:

• Fabric Filter Systems

• Dry Electrostatic Precipitators

• Wet Electrostatic Precipitators

• Dry Sorbent Injection Systems

Each system identified has a multitude of subsystems requiring structural, mechanical and 

electrical expertise. Our engineers and technicians are available to assist you with scheduled 

inspections or specific troubleshooting to correct a known problem.

INSPECTIONS

Typical items of interest are as follows:

• Excessive corrosion

•	 Casing, hopper and duct leaks

• Bag failures

• High spark rate issues – ESP

• Internal equipment alignment problems

• Gas distribution problems

• Auxiliary fan failures

• Heater failures

• Controls calibration

• Grounding problems

• Ash and dust removal problems

• Specific material handling failures

• Power supply failures

• Damper failures

• Evaluation of process changes to system
Air Pollution Control Systems: Parts and Service Guide 9

SEI has been providing our customers with engineers, service technicians and specialized craft 

labor for 40 years. SEI’s maintenance crews travel throughout the contiguous United States 

serving the power generation, pulp and paper, refinery, cement and other markets. Our specialty 

is maintaining electrostatic precipitator and fabric filter systems.

With over 500,000 craft-hours annually, our field crews are supported by technical staff in Pensacola, 

Florida and Westerville, Ohio. In addition, our steel fabrication facility can manufacture most any 

steel component needed on an emergency basis in support of our traveling maintenance teams. 

Thereby preserving our motto:

 If we do not have it, we will find it 

 If we cannot find it, we will make it.

Since beginning business in 1973, SEI has had 

numerous long-term maintenance contracts 

whereby our personnel were stationed at a 

particular facility permanently. Some of these 

long term maintenance relationships spanned 

more than 20 years. SEI has supported full 

time maintenance teams in Florida, and in two 

Virginia locations in the past. 

Most recently SEI supports its customer base 

with both long-term contracts and annual firm 

proposals in support of our clients’ maintenance 

needs. SEI is proud to note that its specialty in 

the maintenance arena centers on fixed price, 

fixed schedule contracts. We believe that we 

bring the most value to many of our clients by arriving on time, doing quality work on a defined 

scope and leaving on time. Most of our clients need maximum production uptime and minimum 

downtime.

We believe that it is our job to keep the plant’s equipment running with minimum disruption 

in contract management. SEI’s field crews are supported by a full-time safety team and 

field quality control personnel.

REPAIR & MAINTENANCE
10 Southern Environmental, Inc.

FABRICATION FACILITY

SEI is a complete in-house design build mechanical contractor, providing domestic and 

international industrial metal fabrication and erection work. Our 100,000 ft2 office and fabrication 

facility houses the equipment needed to do virtually any type of metal fabrication. SEI has a 

completely enclosed sandblast and paint building as well as a 10,000 ft2 warehouse. Our 10-

acre campus facilitates storage of large fabrication orders. Company trucks allow us to remain in 

complete control of quality from time of purchase to final installation. When a project is awarded, 

your company can be assured it will receive the highest quality of service at each phase of design, 

fabrication, shipping and installation.

Listed below is some of our fabrication equipment: 

Shears

• 1 – 12’ – 10 gauge capacity

• 1 - 10’ – 1⁄4” capacity

• 1 – 10’ – 1⁄2” capacity; 3/8” SS capacity

Hand Brake

• 1 – 16 gauge capacity

Automated Hole Puncher

• 1 – 100 ton capacity

Cut-off Saw

• 1 – 14” diameter blade

Power Brake – 200 ton

• 12’ – 1⁄4” plate capacity

• 8’ – 3/8” plate capacity

• 6’ – 1⁄2” plate capacity

• 1 Powerbrake 10’ – 16 gauge capacity

Power Roller

• 1 – 8’ wide – 1⁄4” capacity

• 1 – 5’ wide – 1⁄4” plate capacity

• 1 – 4’ wide – 16 gauge capacity

• 1 – 5’ wide – 16 gauge capacity

Lock Former 

• 1 – 16 gauge capacity

• 60” wide automated coil line

• 1 – 14 gauge maximum

Band Saw

• 20” throat

Forklifts

• 1 – 15,500 pound lift

• 1 – 12,000 pound lift – new

• 1 – 6,000 pound lift

• 7 – 5 ton capacity overhead shop cranes

Plasma cutters Table 10’x43’ (Extreme 

3100 Cutting Machine)

• 1 – up to 2” SS plate

• 1 – up to 2-1/2” CS plate

• 10 – Oxyacetylene

Welding Machines

• 24 MIG Systems

• 2 DC Power Sources (SMAW)

• 5 TIG Systems 
Air Pollution Control Systems: Parts and Service Guide 11

ESP 

Replacement

Parts:

Wet & Dry
12 Southern Environmental, Inc.

DISCHARGE ELECTRODES

RIGID DISCHARGE ELECTRODES (RDEs)

For more than 20 years SEI/ELEX 

electrostatic precipitators have been 

equipped with our patented RS Discharge 

Electrodes.

The RS Discharge Electrode consists of a 

rigid tubular mast to which emitter points 

are positively attached by spot welding. 

The RS Discharge Electrode is, in turn, 

firmly connected to its own suspension system.

This unique electrode is incorporated in over 1,000 SEI/ELEX precipitators with more than 

500,000,000 linear feet of installed electrodes worldwide.

• It is unbreakable and not susceptible to electrical erosion or mechanical wear, which are the 

principal causes of discharge electrode failure.

•	 Improved Cleaning Effects. The vibrations set up by the rapping systems are transmitted 

over the entire length of each and every electrode.

•	 Optimum Corona Effect. The corona discharge is guaranteed at every point because the 

points are geometrically disposed throughout the whole effective column of the precipitator. 

The excellent corona distribution ensures optimum charging of particles; therefore, a superior 

and constant cleaning efficiency is achieved.

•	 No Bending or Distorting. The provisions of suitable guides ensure that the RS Electrode 

will not bend or deform, even when it is subjected to excessive variations of temperature in 

the precipitator.

• Easy and quick installation of the RS Electrode in gas passages spaced from 8” to 16”.

• The RS Discharge Electrode is essential to the high efficiency and reliability required of 

the precipitator. 

SEI / ELEX

Discharge Electrode
Air Pollution Control Systems: Parts and Service Guide 13

DISCHARGE ELECTRODES

Why are so many precipitator manufacturers copying the SEI style Rigid Discharge Electrode? 

There is bound to be confusion, but it is easy to tell the original – SEI’s RS Electrode.

• Look for equally spaced dual emitter sources. They assure equal corona over the entire length 

of the electrode.

• Look for cantilevered suspension of the emitter arms away from the center support. It is a 

design feature that makes sure dust cannot build up and cover the discharge points.

The SEI Rigid Electrode has been retrofitted into 8”, 9”, 10”, 11”, 12” and 16” spaced units replacing 

weighted wires.

• More installations than any other manufacturer

• Over 20 years installed experience

• Over 1,000 precipitator installations worldwide

• Over 500,000,000 linear feet in service

Cantilevered Suspension of 

Dual Emitter Points Eliminates 

Dust Build-Up and Guarantees 

Uniform Corona Distribution.

Heavy Corten 9 Gauge Top 

and Bottom Attachment Clips 

Eliminate Hanger Failure. Roll Formed 2-Piece Tubular 

Support Member Eliminates 

Fatigue and Breakage.

How to tell the original from the copies:

Do not settle for a copy – Insist on the original!
14 Southern Environmental, Inc.

REPLACEMENT WIRES AND SHROUDS

When properly designed and manufactured, weighted wires can provide you with years of reliable 

cost effective service.

Smooth Round 

Wire

Barbed Wire Dual Strand Wire Square Wire Ribbon Wire

Choose the shroud style that best suits your needs from the illustrations on the following page. 

Be sure to record the required dimensions listed below.

A – Overall length

B – Top shroud length

C – Bottom shroud length

D – Wire Diameter

E – Top shroud diameter

F – Bottom shroud diameter

G – Electrode hanger style (see next page)

H – Weight hanger style (see next page)

A

G

H

F

D

E B

C

DISCHARGE ELECTRODES
Air Pollution Control Systems: Parts and Service Guide 15

DISCHARGE ELECTRODES
16 Southern Environmental, Inc.

DISCHARGE ELECTRODES

WEIGHTS

Weights are used on rigid discharge electrodes and weighted 

wire systems. The weights are designed to keep the RDE’s 

and wires straight and aligned, also to deter any swaying 

which could lead to breakage through arcing and fatigue. 

We offer a designed weight for our unique RDE’s and can 

provide a direct replacement casting for most weighted wire 

OEM weights.

SEI Standard Rigid Discharge Electrode Weights
Air Pollution Control Systems: Parts and Service Guide 17

COLLECTING SURFACES

COLLECTING PLATES

Solid Collecting Plates

Solid collecting surfaces are roll-formed surfaces that are factory 

assembled to form a single-piece baffled structure, providing 

maximum stiffness, optimum gas exposure, uniformity of profile 

and require no field assembly.

The smooth curving geometry of the top and bottom edges of 

the collecting surfaces prevent edge effect arc-over where the 

discharge electrodes enter and leave the collecting field.

The arrangement of the collecting plate baffles are specifically 

designed to match the discharge electrode arrangement for 

your application. This design flexibility ensures the optimum 

relationship between the collecting plates and the discharge 

electrodes.

Segmented Plates

This type of collecting surface is comprised of roll-formed 

segmented steel collecting surfaces.

The roll-formed ribbed design resists bowing and resulting 

misalignment due to temperature excursions and rapping 

forces. Aerodynamically, when properly rapped, the collected 

dust particles are effectively sheared from the entire length of 

the plate segment with minimum re-entrainment.

The supporting “tadpoles” are designed to prevent edge 

effect arc-over where the discharge electrodes enter and 

leave the collecting field.
18 Southern Environmental, Inc.

COLLECTING SURFACES

PLATE STRAIGHTENERS

Having problems with bowed collecting plates? 

Plate straighteners are designed to keep the collecting 

plates apart and in their original positions.

Whether you need replacement plate straighteners or 

you would like to install new ones, we can supply you 

with what you need.

COLLECTING PATCH 

PLATES

Intact collecting plates are vital to maintaining 

the efficiency of your precipitator. Plates that 

are damaged could decrease the rapping 

effectiveness, gas flow distribution and 

cause reduction in corona generation. The 

corrosion of the plates decreases the amount 

of available collecting surface and the rough, 

jagged edges could cause arcing. SEI can 

offer a designed patch plate to attach to the 

existing collecting plate to help eliminate 

these potential problems.
Air Pollution Control Systems: Parts and Service Guide 19

Electrostatic precipitators require various electronic 

components to function optimally:

• The transformer/rectifier set is specifically 

designed to provide the high voltage DC necessary 

for electrostatic precipitation.

• T/R Controls - The control units contain all 

components necessary for controlling and 

protecting a T/R set. Serial data ports are included 

for transmitting and receiving data from a central 

control system.

• Microprocessor-based controls are used to manage and control the rapping of the precipitator 

for proper cleaning of the collecting plates and discharge electrodes.

• A computer program monitors, predicts and troubleshoots electrostatic precipitator 

performance.

Whether you need a transformer/rectifier set, controls or current limiting reactor, we can facilitate 

your order. We provide AVC’s and T/R’s for any requested manufacturer.

ELECTRONICS & CONTROLS

ELECTRONICS & CONTROLS

•	 T/R Controls

•	 Rapper Controls

•	 Current Limiting Reactors

•	 Electronic Components

•	 Transformer / Rectifier Sets

•	 Switchmode Power Supplies

Photos courtesy of NWL and Stock Equipment
20 Southern Environmental, Inc.

ELECTROMAGNETIC RAPPERS

The acceptable balance of rapping intensity, 

frequency and duration is vital for optimum 

precipitator performance.

Southern Environmental supplies rappers for 

dependability and minimal maintenance.

Some of the rapper features include:

• The rappers are “solenoid-driven,” 

meaning an electric solenoid lifts the 

plunger which is then returned by 

gravity to impact the rapper.

• 20 pound plungers with stainless steel 

laminated ends eliminate magnetizing.

• Coils are available in 120v DC or 240v 

DC.

• Shaft mounted or roof mounted

• Pigtail or junction box electrical 

connections.

PNEUMATIC RAPPERS

Inexpensive and reliable pneumatic rappers successfully remove 

persistent deposits.

The air-cushioned pistons lessen stress on plate heads.

The mounting design is tapered to fit most metal and insulated 

shafts.

RAPPERS
Air Pollution Control Systems: Parts and Service Guide 21

RAPPER COMPONENTS

Our rapper components are available individually or as custom-engineered systems that 

specifically suit your needs.

Our inventory consists of:

• Steel Rapper Shafts

• Insulated Rapper Shafts

• Boot Seals/Clamps

• Impact Caps

• Double-Tapered Adapters

• Ground Straps

• Rapper Sockets

• Rapper Donuts

RAPPER COMPONENTS

GROUND STRAPS

Ground straps insure electrical bonding of the 

rapper, the stationary anvil rod, and the ESP 

casing to prevent electrostatic build up, which 

can result in damage to the rapper controller 

due to electrostatic discharge.
22 Southern Environmental, Inc.

RAPPER COMPONENTS

BOOT SEALS

Boot seals ensure that atmospheric elements such as 

rain and cold air do not enter the ESP.

Leakage of gasses and corrosion of rapper shafts is 

prevented by the positive seal between the rapper 

shafts and nipple guides.

Rapper sleeves that are too small can cause various 

problems including corrosion, particulate buildup and 

binding of the rapper shaft, which ultimately can lead 

to rapping of the roof instead of the plates or discharge 

electrodes.

We offer an assortment of boot seals in various styles 

and materials suitable for your particular application.

RAPPER CAGES

Electromagnetic rappers are designed to drop a piston from their 

housing for both the collecting and high voltage systems. These 

pistons can weigh anywhere from eight (8) pounds to twenty (20) 

pounds. To prevent safety mishaps, rapper cages are used as a 

safety guard on the rapper at the area of the exposed piston. SEI 

can offer a designed rapper cage to attach to the existing collecting 

plate and high voltage rappers to deter safety incidents. 

RAPPER INSULATORS

Rapper insulators electrically isolate the 

discharge electrode rappers while dispersing 

the mechanical forces required to generate 

vibration or shock in the high voltage 

system. 
Air Pollution Control Systems: Parts and Service Guide 23

INSULATORS

The ceramic material of choice for discharge electrode 

system support insulators, rapping system insulators 

and feed-through bushing insulators is 85% alumina 

ceramic. These insulators are engineered to perform 

in hostile electrostatic precipitator environments.

This material has been shown to considerably reduce 

the costs associated with repeated system repairs and 

plant downtime. Replacement insulators are available 

for any OEM.

Material Temperature Limitations

Teflon – Up to 450 degrees

FRP – 250 to 400 degrees

Alumina – Up to 1,400 degrees

SEI CAN SUPPLY THE FOLLOWING 

INSULATOR PARTS:

• Support Insulators

• Anti-Sway Bars

•	 Alumina

•	 Teflon

• Rapper Shafts

•	 Alumina

•	 Fiberglass

•	 Porcelain

• Wall Bushings

• Stand-Off Insulators

• Bus Duct Insulators

• Feed-Through Insulators

• Insulator Gaskets

• Drive Shaft Insulators
24 Southern Environmental, Inc.

INSULATORS

COMPRESSION SPRINGS

A component of the high voltage suspension 

system is compression springs. They are used 

to support and distribute the weight of the system. 

There are varying sizes to choose from which are 

dependent on the weight and frame size of the 

high voltage system. 

INSULATOR HEATERS

Rapid temperature changes or the introduction 

of moisture can cause tracking and cracking of 

insulators. Heaters should be utilized to prevent 

condensation and ash build up by warming 

the insulators prior to start up.

SUPPORT INSULATORS

Support insulators physically support and electrically isolate the 

high voltage system from ground. The support insulators are 

designed to support compressive strength loads generated by 

the high voltage electrodes and frames. 

ANTI-SWAY INSULATORS

Anti-sway insulators are connected to the high voltage guide 

frame to sustain alignment and stability. The anti-sway insulators 

are used to prevent the high voltage system from swaying. One 

end of the insulator is attached to a grounded portion of the ESP 

while the other end is attached to the lower high voltage frame. 

The material of choice is either Alumina or Teflon. The Alumina 

insulator is available in a flat bar or a solid round bar. The flat bar 

is also available in Teflon. 
Air Pollution Control Systems: Parts and Service Guide 25

PURGE AIR SYSTEMS

PURGE AIR SYSTEMS

Purge Air Systems protect high-voltage support insulators 

from moisture and dust that could accumulate on their 

surfaces and cause them to fail.

Support insulators provide many years of use when properly 

maintained, such as preheating prior to start-up. The constant 

flow of dry heated air prevents condensation and prevents 

flue gas from entering.

Volume, temperature and pressure of the purge air are 

critical design parameters that vary significantly. Southern 

Environmental designs each purge air system to satisfy the 

specific requirements of each application.

Purge Air System 

Components:

• Heaters

• Filters

• Fans

• Heater Box

• Purge Air Controller

• Heater Controller
26 Southern Environmental, Inc.

PURGE AIR SYSTEMS

PURGE AIR FILTERS

Filters are utilized on the Purge Air to prevent foreign matter from 

entering the system. Filters should be changed or cleaned on a 

routine basis.

INSULATOR COMPARTMENT

Insulator compartments provide heated purge air 

to keep the high voltage insulator of a WESP free 

from dirt and moisture that can accumulate on their 

surfaces and cause them to fail. 

The insulator compartment shown is a low purge 

flow design with an integral heating element 

that uses a very low flow of air (or inert gas for 

combustible gas applications). These units can 

be designed to permit use on any WESP unit. 

Engineering support is available to allow an exact 

match for any application. 

 Insulator Compartment Components:

• Heating elements

• Temperature controls

• Sight glasses

• Purge flow controls 

 (complete with flow alarms)
Air Pollution Control Systems: Parts and Service Guide 27

ACCESS

DOORS 

Southern Environmental can provide all types of 

doors for precipitators, fabric filters and ductwork. 

Our standard carbon steel doors resist harsh 

environments and hard wear, providing years of leakfree service.

We offer round and rectangular doors in various 

standard and custom sizes for your specific 

application. Stainless steel doors are also available.

Door seals require regular inspection and replacement. 

Over time, seals may shift, deform, become brittle or fail 

to seal properly due to warping of the door itself.

Stock material consists of a variety of quality door seals 

to meet the specific needs of any application.

High and low temperature caulking material is also 

available.

One tube of caulking material can cover a length of 25 

feet. (Expect to use an additional 10% on corners and 

splices.)

DOOR SEALS
28 Southern Environmental, Inc.

GROUND STICKS

LADDERS & PLATFORMS

Would improved ladders, stairs and platforms make your ESP maintenance easier and more 

efficient? If you are in need of ladders or platforms, Southern Environmental can help.

We custom design, fabricate and install ladders and platforms to suit your specific needs. Access 

can be fabricated in carbon steel, stainless steel or fiberglass. Coating options can be provided 

by SEI or we can coat the equipment to your specifications.

Ground sticks are used to positively de-energize/

ground the precipitator before entering the door. They 

are a critical safety component to have at each access 

point to an ESP.

ACCESS

KEY INTERLOCK SYSTEMS

A functioning key interlock system provides protection for your precipitator and for your 

operators. The interlocking system ensures the voltage has been locked out and the equipment 

rendered safe before entry is permitted.
Air Pollution Control Systems: Parts and Service Guide 29

PROCESS DAMPERS

Most air pollution control systems incorporate 

process dampers for flow control, compartment 

isolation or bypass. Dampers can be actuated 

manually, electrically or pneumatically. SEI can 

provide replacement parts, such as actuators, 

solenoids, limit switches, bearings, seals or 

linkage, for your existing dampers. We can also 

supply complete replacement dampers to match 

your existing damper specifications, including size, 

flange, bolt pattern, pressure, temperature, flow 

and actuation. Damper styles include butterfly 

(wafer), multi-blade louver, poppet and guillotine.

Damper Components

• Seals

• Actuators (pneumatic and hydraulic cylinders)

• Control Solenoid valves

• Limit Switches

EXPANSION JOINTS

Expansion joints are utilized on both process gas duct and 

in process liquid (irrigation and flushing fluid) systems. 

Expansion joints can be tailored to the application as 

required to exceed the original process conditions, thereby 

providing an equal or superior replacement to original 

equipment. SEI’s engineering department can assist in 

determining failure modes to offer the optimum materials 

and construction in the full range of expansion joints to 

restore or improve the overall system performance. 

DAMPERS & EXPANSION JOINTS
30 Southern Environmental, Inc.

PROCESS INSTRUMENTATION

Various process instrumentation is available to replace and upgrade 

an assortment of critical operational parameters. 

• Pressure transmitters (gauge and differential)

• Temperature transmitters

• Thermocouples

• Flowmeters (magnetic flowmeters, turbine meters, rotameters 

and totalizers)

• Flow switches

• pH analyzers/transmitters

• Level transmitters

• Level switches

• Conductivity, turbidity and specific ion analyzers and transmitters

All popular communication and data handling protocols 

are available. Process control equipment that can be 

smoothly integrated to existing DCS or PLC is available.

PROCESS INSTRUMENTATION
Air Pollution Control Systems: Parts and Service Guide 31

PUMPS

Pumps utilized to supply irrigation and flushing 

water are essential to the optimum operation of 

any WESP. 

Pump Components

• Seals

• Impellers 

• O-rings

• Motors 

• Couplings 

• Complete pumps

SPRAY NOZZLES

Proper operation of a WESP requires aggressive 

cleaning of the internal components on varying 

frequencies to remove material buildup that is inherent 

in the operation of any WESP system. Spay nozzles are 

available to cover the range of potential requirements. 

SEI can offer direct replacement components or 

engineer a retrofit to enhance the cleaning effectiveness 

of your existing equipment. Two-fluid nozzles are 

available to ensure 100% saturation of the flue gas.

WATER RECYCLE SYSTEM
32 Southern Environmental, Inc.

FILTERS

Process fluids utilized in WESP systems contain varying 

amounts of entrained suspended solids that require 

removal from the process fluid streams in order to 

achieve the optimum design performance of a WESP. 

We provide an extensive selection of filter equipment to 

replace existing filter systems or, when the application 

demands have changed, upgrade the filtration equipment 

to address changing performance requirements in the 

fluid system. 

Filter Components

• O-rings 

• Seals

• Filter media (bags, cartridges, screens, etc.)

• All related controls

• Complete filtration systems

VALVES

Valves are utilized in a variety of WESP support equipment. Valves are available for all liquid 

systems for process fluid isolation as well as flow control in the full range of available materials to 

suit any process requirements. Actuators are also available for on/off service as well as modulating 

service as either direct replacements or add-on equipment where an enhanced level of automated 

process control is required. Isolation and control valves for purge air and water are available to 

ensure optimum WESP operation. Check valves in all materials are available. 

WATER RECYCLE SYSTEM
Air Pollution Control Systems: Parts and Service Guide 33

Fabric Filter 

Replacement Parts
34 Southern Environmental, Inc.

BAGS & CAGES

Bags and cages are the heart of any fabric filter 

system. Proper material selection, based on 

process conditions and emission guarantees, 

bag to cage fit and bag to tubesheet fit is 

essential for a system to operate properly. If you 

are having short bag life, high pressure drop or 

not meeting emission limits then our technical 

experts can recommend the appropriate bag 

material. 

BAGS

Southern Environmental, Inc. can provide you with bags that ensure maximum filtration efficiency, 

cake release and durability. 

Many variables affect the type of fabric needed for a specific system. These variables include:

Use the chart below to assist in selecting the appropriate bag to meet your filtration system needs.

Fabric Construction

Tensile 

Strength

Abrasion 

Resistance

Acid 

Resistance

Alkali 

Resistance

Support 

Combustion Continuous* Surge*

Cotton Woven Good Good Poor Good Yes 180 200

Polypropylene Woven / Felted Excellent Excellent Excellent Excellent Yes 200 200

Nylon Woven Excellent Excellent Poor Excellent Yes 200 250

Wool Woven / Felted Poor Fair Good Poor No 200 230

Homopolymer 

Acrylic

Woven / Felted Good Good Very Good Fair Yes 260 284

Copolymer 

Acrylic

Woven / Felted Average Fair Good Fair Yes 230 248

Polyester Woven / Felted Excellent Excellent Fair Fair Yes 275 300

Aramid Woven / Felted Very Good Excellent Fair Good No 375 425

Teflon® Woven / Felted Average Fair Excellent Excellent No 500 550

Fiberglass Woven / Felted Excellent Fair Good Fair No 500 550

PPS Woven / Felted Very Good Excellent Excellent Very Good No 375 425

P84 Woven / Felted Very Good Excellent Very Good Fair No 500 550

*Maximum Recommended

Operating Temperature °F

• Temperature

• Moisture Level

• Particulate Size

• Gas Stream Chemistry

• Air-to-Cloth Ratio

• Particulate Abrasiveness

• Mechanical Factors, such as cleaning 

style, installation etc.
Air Pollution Control Systems: Parts and Service Guide 35

2 PIECE ROUND

CAGE CONNECTIONS

SLIDE LOCK 2 PUNCHES

FINGER

TWIST-LOK TM

SLIDE LOCK 1 PUNCH

CAGES

Proper support of your filter bags is critical for efficient 

cleaning and long bag life. Over time, cages become 

corroded, which can cause wear and premature bag 

failure. We can assist you in selecting the proper 

cage design, material and fit.

Filter cages are available in mild steel, galvanized 

steel, epoxy coated or stainless steel. If designing for 

a corrosive environment, multiple piece cages can 

be provided with dissimilar metals at the connecting 

point.

MULTIPLE PIECE CAGES

The recent advances in long bag technology necessitate the 

use of multiple piece cages. The connection between cage 

pieces must be designed to withstand the rigors of installation 

and everyday operation without becoming a maintenance 

burden. SEI offers several cage connection options. We 

can replace your existing cages in-kind or assist you with an 

upgrade to the latest technology.

RIGID WIRE CAGES

These cages are manufactured by pulling wire off a coil, through a straightening die and cutting 

it to precise lengths. These individual stringer wires are then loaded into a magazine which 

maintains the exact spacing of the wire. They are fed to the welding mandril and welded to the 

inside of the bottom pan. Spacer rings are then attached using digitally controlled resistance 

welding. The top component is fixture welded to the tube to maintain finished cage length and 

assure proper alignment and installation.

The cage spacer rings are automatically manufactured by pulling wire off a coil, through a cutting 

die and around a coiling pin which forms the wire into an open ring. Welding jaws grasp the 

ring and close the ends, applying pressure and introducing a precisely controlled pulsing 

current which fuses the ends into a continuous ring. Statistical process control techniques 

monitor quality. Standard and specialty cage tops are available. Crimped bottom pans 

are available for mesh and welded bottom pans are available for rigid wire cages.

BAGS & CAGES
36 Southern Environmental, Inc.

BAGHOUSE PARTS

CLAMPS

Clamps are a necessary part of proper bag installation and are designed 

to increase bag life by decreasing the chances of clamp failure. Clamps 

are manufactured in many sizes and are designed for use with raw 

edge top bags or cord bottom bags fitted on a thimble.

Before purchasing, you should consider the many reasons why clamps 

can fail: misapplication, misplacement, overtorquing and reuse of old 

clamps.

VENTURI

A venturi is an integral component of some pulse-jet collectors. It directs the 

blast of compressed air into the center of the filter bag to prevent abrasion 

caused by misaligned blowpipes and turbulent airflows. If venturis become 

damaged or worn, compressed air doesn’t gain the velocity required to 

effectively clean the filter bags.

PULSE VALVE

Pulse cleaning of the fabric filter bags is critical to maintain system pressure 

and facilitate smooth system operation. Additionally, this cleaning extends 

the life of the bags by clearing the material from the bags prior to idling the 

system. Replacement pulse valves are available as total units, rebuild kits 

or coil only. Although other sizes are also available, typical pulse valve sizes 

range from 1.5 to 3”. 120 VAC or 24 VDC are the standard voltages supplied; 

however, other voltages are also available. Various diaphragm materials are 

available as required for your process.

PULSE VALVE REBUILD KITS

AND COILS

Pulse valve rebuild kits are available in various materials based on your 

process requirements. 

Replacement pulse valve coils can be purchased separately. 120 

VAC or 24 VDC are the standard voltages supplied; however, other 

voltages are also available.
Air Pollution Control Systems: Parts and Service Guide 37

PULSE TIMER BOARD

The pulse timer board is an integral 

part of the bag pulsing system. Pulse 

timer boards ensure proper cleaning of 

your baghouse. The operation times are 

adjustable and the number of outputs are 

3, 10, 20 and 32. The standard voltage is 

120 VAC, other voltages are available.

TUBESHEETS

The connection between the filter bag and tubesheet is critical 

to both environmental performance and bag life. The integrity of 

this connection depends on tight tolerances for the bag, cage and 

tubesheet hole. Corrosive flue gas will attack the tubesheet and, 

over time, the hole diameter tolerance will be lost. SEI can supply 

and install replacement tubesheets that meet or exceed the original 

manufacturers specifications and tolerances.

BAGHOUSE PARTS

PULSE HOSES

Pulse valve hoses and hose clamps are available. 

Standard hoses are 4” long with a maximum operating 

temperature of 200°F. Hoses are constructed of aramid 

polyester wrapped Neoprene and have a working 

pressure of 178 psig. Other lengths and specifications 

are available. 

AUTOMATIC PURGE VALVE

Automatic purge valves are designed to eliminate moisture buildup in the compressed 

air header before entering the unit, causing corrosion and dustcaking on the top of bags. 

This valve is located at the bottom of the air header assembly and connected to a pulse 

valve. When the pulse valve fires, the valve opens a discharge port on the air header 

assembly, removing excess moisture.
38 Southern Environmental, Inc.

BAG LEAK DETECTION

Quickly finding and replacing broken or leaking bags is critical to maintaining compliance with 

today’s strict emission standards. It is also important to locate a broken bag before the dust can 

contaminate the clean side of adjacent bags, thereby causing premature failure.

SEI can provide fluorescent powder to be injected upstream 

of the baghouse. The powder will take the path of least 

resistance and find its way to the source of the leak. Some of 

the fluorescent powder will accumulate around the top of the 

leaking bag where the velocity is reduced, allowing fallout.

A blacklight is then used to locate the areas of accumulated 

powder. The fluorescent powder glows brightly under the 

blacklight. Once leaks are found and repaired, a second leak 

test can be performed using a different color powder to verify 

that all leaks have been eliminated.

Leak detection powder is available in a variety of colors. It 

is important to select an appropriate color for your specific 

application and it is best to alternate colors for each round of 

testing. One pound of leak detection powder is recommended 

for every 1000 square feet of filter cloth.

•	 Pink - Appropriate for all industries

•	 Orange - Should not be used where iron 

oxide is present.

•	 Green - Generally good for all industries.

•	 Yellow - Good for all industries except 

where high sulfur concentrations are 

present.

SEI can provide a complete leak detection kit, 

including powder, black light, charger and UV 

protection glasses. SEI can also send one of 

our trained professionals to perform the leak 

check for you. 

FLOURESCENT

SATURN YELLOW

FLOURESCENT

IRIDESCENT BLUE

FLOURESCENT

ELECTRIC VIOLET

FLOURESCENT

AURORA PINK

FLOURESCENT

BLAZE ORANGE

FLOURESCENT

SIGNAL GREEN

BAGHOUSE PARTS
Air Pollution Control Systems: Parts and Service Guide 39

BAGHOUSE PARTS

BAG PRECOAT

Precoat material is a dry, inert powder. 

When introduced into the gas stream 

at the inlet of your baghouse it coats 

and conditions the fabric filters 

promoting maximum particulate 

collection efficiency and effectiveness. 

Precoat material can be used as an 

initial control layer for start-ups to 

precondition fabric filters. It can also 

be continuously injected into the gas 

stream to blend with the process 

dust to help collection efficiency. The 

precoat material forms a uniform 

three-dimensional, porous dust cake 

that is ideal for efficient and effective 

baghouse operation. Due to its multiwalled, curved structure of varying 

sizes and shapes, precoat material 

provides a naturally well balanced particle size distribution that promotes increased air flow, thus 

reducing differential pressure and energy costs for your baghouse.

Benefits:

• Aids in collection efficiency while optimizing airflow.

• Protects against blinding and plugging your fabric filters.

• Inhibits sparks in the airstream due to its high melting point.

• Absorbs damaging moisture, oils and hydrocarbons due to its chemically inert and neutral pH 

nature.

One pound of precoat material will cover over 22 ft2

 of cloth with a 1/16” coating; compared with 

lime and flyash that will only cover up to 5 ft2

 of cloth per pound.
40 Southern Environmental, Inc.

BAGHOUSE PARTS

Southern Environmental can provide all types of doors for 

fabric filters, precipitators and ductwork. 

Our standard carbon steel doors resist harsh environments 

and hard wear, providing years of leak-free service.

We offer round and rectangular doors in various standard 

and custom sizes for your specific application. Stainless 

steel doors are also available.

DOORS

Door seals require regular inspection and replacement. Over 

time, seals may shift, deform, become brittle or fail to seal 

properly due to warping of the door itself.

Stock material consists of a variety of quality door seals to 

meet the specific needs of any application.

High and low temperature caulking material is also available.

One tube of caulking material can cover a length of 25 feet. 

(Expect to use an additional 10% on corners and splices.)

DOOR SEALS
Air Pollution Control Systems: Parts and Service Guide 41

REMOVABLE TOP LIDS

Southern Environmental’s removable top lid design 

incorporates the pulse header, pulse valves and 

blow pipes into the lid. This allows for fast and safe 

maintenance, as the entire tubesheet is exposed and 

bags and cages can be immediately accessed without 

removing individual blow pipes once the lid has been 

lifted. Our design also incorporates integral stacking 

legs so that the removed lid can be placed on top of 

an adjacent compartment without risk of damage to the 

pulse system. 

SEI can repair or replace damaged top lids as well as retrofit them onto existing fabric filters.

HOPPER VIBRATOR

To aid in moving the material out of the compartment hoppers, 

electro-mechanical and pneumatic vibrators are installed. We 

can offer replacement units for use on your equipment. 

LEVEL PROBE

Single point vibrating level probes (pictured left) are installed 

in the system to monitor reagent storage levels, material flow 

and hopper level. These level probes are available for standard 

temperature duty (300°F) and higher temperature applications. 

(One is used in the baghouse and one is used in the Ash 

Removal system).

BAGHOUSE PARTS
42 Southern Environmental, Inc.

EVAPORATIVE COOLER PARTS

SPRAY NOZZLES AND LANCES

Proper spray atomization is key to successful 

evaporative cooler operation. Over time, nozzles 

can wear due to erosion and/or corrosion. SEI can 

supply replacement nozzle tips, nozzles or entire spray 

lances to restore the evaporative cooler performance 

to its original design specifications. The SEI spray lance design allows 

for in-place adjustment to ensure proper nozzle placement and spray 

direction. Standard configurations are available in 316L stainless steel 

and 440 stainless steel. Other materials such as Hastelloy C276 and 

Inconel 600 are also available. 

HOSES

SEI can supply replacement hoses for connecting spray 

lances to the supply header. Hose materials are selected 

to meet your site specific temperature, pressure and 

environmental requirements.

PUMP SYSTEMS

SEI can provide replacement pumps, 

control valves and actuators for your 

evaporative cooler pump system. SEI 

also designs and builds our own pump 

skids and can provide an entire new 

pump skid designed to reliably supply 

the water and atomizing air required 

for optimum evaporative cooler 

performance.
Air Pollution Control Systems: Parts and Service Guide 43

PROCESS DAMPERS

Most air pollution control systems 

incorporate process dampers for flow 

control, compartment isolation or bypass. 

Dampers can be actuated manually, 

electrically or pneumatically. SEI can provide 

replacement parts, such as actuators, 

solenoids, limit switches, bearings, seals 

or linkage, for your existing dampers. We 

can also supply complete replacement 

dampers to match your existing damper 

specifications, including size, flange, bolt 

pattern, pressure, temperature, flow and 

actuation. Damper styles include butterfly 

(wafer), multi-blade louver, poppet and 

guillotine.

GAS STREAM COMPONENTS

ID FAN COMPONENTS

Should your system fan require a replacement coupling, belts, bearings, shaft or other 

parts, our spare parts specialists can assist you in the supply of OEM replacement parts. 

If your entire fan needs to be replaced or upgraded, our engineers can help you be sure 

that you are getting the right fan for the job.

EXPANSION JOINTS

Expansion joints are utilized on both process gas duct and in 

process liquid (irrigation and flushing fluid) systems. Expansion 

joints can be tailored to the application as required to exceed the 

original process conditions, thereby providing an equal or superior 

replacement to original equipment. SEI’s engineering department 

can assist in determining failure modes to offer the optimum 

materials and construction in the full range of expansion joints to 

restore or improve the overall system performance. 
44 Southern Environmental, Inc.

REAGENT BLOWER AIR INTAKE FILTER ELEMENT

For systems pneumatically conveying reagent for process gas conditioning, it is imperative the 

conveying air supply remain constant. To protect your conveying air equipment, replace your inlet 

air filter. We offer replacement filter elements for your specific equipment.

DOWNSPOUT FILTER

A clear reagent injection line is critical for maintaining dependable reagent 

injection. Ambient air is pulled through the downspout filter and through the 

injection line. Replacement air inlet filter elements are available through our 

spare parts department.

REAGENT FEEDER BEARING

To keep your reagent feeder operating smoothly, replacement auger drive catridges are available 

through our spare parts department.

REAGENT FEEDER SCREW / 

AUGER AND FEED TUBE

Our reagent feeders offer optimum flexibility should you 

require adjusting your reagent feed rates outside of the 

VFD range. This can be achieved by swapping out 

the feeder screw and auger by a simple 1/4 turn of the 

auger and feed tube.

REAGENT STORAGE
Air Pollution Control Systems: Parts and Service Guide 45

Case Histories
46 Southern Environmental, Inc.

Canfor Pulp Limited Partnership

Northwood Pulp Mill

5353 Northwood Pulp Mill Road

Prince George, British Columbia, Canada

Challenge:

Existing recovery ESP was old and undersized for new emission standards.

Southern Environmental’s Solution:

Southern Environmental, Inc. provided a new state-of-the-art Recovery ESP with 

POWER PLUS transformer technology, using SEI-ELEX electrodes. The ESP is designed with a dry bottom conveyor system and heated shell. The SEI design utilizing the high frequency transformers is cutting edge application for recovery boiler 

ESPs. SEI has been on the forefront utilizing this technology in other applications 

since 2002.

Project Duration:

•	 PO Received 6/4/10

•	 Materials delivered to site by 2/28/11

•	 Start-up 10/1/11

Detailed Engineering 

in the following disciplines:

•	 Structural

•	 Mechanical

•	 Electrical

•	 1/12 Physical Scale Model Study

Fabrication and Erection Services:

•	 ESP Fabrication

•	 Field Technical Support

CASE HISTORIES
Air Pollution Control Systems: Parts and Service Guide 47

 Application / Operating Conditions:

Inlet design flue gas temperature:	 421°F

Design flue gas flow:	 	 	 435,000 acfm

Design flue gas moisture:	 	 22.5% (by vol)

Design flue gas O2 (dry):	 	 4.0% (by vol)

Maximum inlet loading:	 	 	 8.7 grains/dscf (Corr. To 8% O2)

Flue Gas Distribution @ ESP Inlet:	 ICAC EP-7 or better

Virgin Black Liquor Solids firing rate:	 3.75 MM lb/day

Virgin Black Liquor Solids conc.:	 	 76.5%

Performance Guarantee:

When operated at the operating conditions noted above the ESP will perform well below the guaranteed 

outlet emission levels noted below:

 Both Chambers Operating:

Guaranteed Outlet Emissions:	 	 0.021 grains/dscf (Corr. To 8% O2)

	 	 	 	 	 	 60 mg/dscm (Corr. To 8% O2)

Guaranteed Efficiency:	 	 	 99.7%

 One (1) Chamber Offline (50% Boiler Load):

Guaranteed Outlet Emissions:	 	 0.021 grains/dscf (Corr. To 8% O2)

60 mg/dscm (Corr. To 8% O2)

Guaranteed Efficiency:	 	 	 99.7%

Scope of Work:

SEI provided detailed engineering, material supply, 

fabrication, construction management and 1/12 physical 

model study, inlet flange to outlet flange, conveyor systems,

slide plates to weather enclosure. The ESP is a two chamber, 

five mechanical field (in direction of gas flow) recovery

precipitator.

SEI provided a climate controlled building at the cold roof 

level that contains rapper controllers, PLCs, MCC equipment, 

PCAMS communication and drag scraper controls.

CASE HISTORIES
48 Southern Environmental, Inc.

Hoosier Energy

Merom Generating Station

5500 W. Old 54, Sullivan, IN 47882

Challenge: The advent of MATS requires greater acid gas and particulate control. 

SEI was tasked with designing an ESP retrofit solution that addresses greater

particulate capture with the addition of dry sorbents upstream of the ESP. The 

solution had to be implemented during an eight week outage subject to limited work 

area.

Southern Environmental’s Solution:

Southern Environmental, Inc. provided 2 new 500 MW state-of-the-art S3 ESPs with 

high frequency power supplies using SEI-ELEX electrodes. The ESP is designed with 

wide plate spacing, top rapped systems, seven foot penthouse and new hoppers. 

The SEI design allowed for reuse of the existing structural steel and construction 

of a new ESP above the ash handling system during an eight week outage. SEI 

achieved far lower emissions within the same footprint and with a much larger inlet 

loading due to DSI/ACI injection for SO3 control.

Project Duration:

•	 PO Received: November 2010

•	 8 week outage on each unit 

•	 Unit #2 Spring 2012

•	 Unit #1 Spring 2013

Detailed Engineering 

in the following disciplines:

•	 Structural

•	 Mechanical

•	 Electrical

•	 Civil

Fabrication and Erection Services:

•	 ESP Fabrication

•	 Field Technical Support

•	 Mechanical Construction

•	 Insulation Installation

•	 Electrical Installation

CASE HISTORIES
Air Pollution Control Systems: Parts and Service Guide 49

CASE HISTORIES

Scope of Work:

Southern Environmental, Inc. provided detail engineering, 

material supply, fabrication, construction and start-up 

services to retrofit the ESPs for Units #1 and #2. The first

unit was installed in the Spring of 2012. The second unit will 

be installed during the Spring 2013 outage. Each unit was 

designed and built from the hopper support steel up including 

new hoppers, structural modifications, casing, internals, roof

and power equipment. SEI’s S3 technology was utilized to 

achieve increased collection efficiency. In addition to the ESP

retrofit work, SEI also performed several SCR catalyst layer

replacements.

 Application / Operating Conditions:

	 Bituminous Coal (Min. HHV-10,500

Btu/lb, Max. Ash - 15%)

Nominal Rating, MW 540

Draft Type Balanced

Maximum Boiler heat input, MBtu/h 5,088

Flue gas inlet temperature, °F 	 340

Flue gas volumetric flow, ACFM (wet) 	 2,400,000

Flue gas inlet pressure, in. wc -13

Maximum Economizer Oxygen, % w 	 4.5

Maximum Air Heater In-leakage, % 	 15

Maximum Inlet particulate loading, gr/acf 4

Fly Ash, LOI, % 	 Under 10

Uncontrolled H2SO4 content, ppm 20-60

Controlled H2SO4 content, ppm ~1

Reagent to be used for H2SO4 control Trona or Sodium Carbonate

Approximate Trona Loading, lb/hr 	 3,700 (45% Na2SO4, 54% Na2CO3)

Approximate Sodium Carbonate 	 3,000 (50% Na2SO4, 50% Na2CO3)

 Loading, lb/hr

Maximum Limekiln dust loading to the 0.35

boiler, % weight of coal

Stack exit inside diameter, ft 	 19’-0”

Performance Guarantee: With the boiler in operation at the conditions noted and the precipitator 

operated in accordance with the instructions provided, the filterable particulate emissions from the

revised particulate collection system will not exceed 0.015 lb/mmBTU while all SMPS’ in service and, 

0.02 lb/mmBTU while one SMPS per ESP chamber is out of service.
50 Southern Environmental, Inc.

Westar Energy, Inc.

Jeffrey Energy Center

25905 Jeffrey Rd.

St. Marys, KS 66536

Scope of Work:

Southern Environmental, Inc. provided detailed engineering, material supply, fabrication, 

construction and start-up services. SEI/ELEX rigid discharge electrodes and High Frequency

Switch-Mode Power Supplies were utilized to achieve increased collection efficiency within

the same footprint. In addition to the rebuilds, SEI also performed several structural 

studies for Westar, as well as designed and installed the proper reinforcement needed to 

accomodate the higher draft system pressures requested.

Application:

•	 3 Units - 750 MW Coal Fired Power Boiler

Project Duration:

•	 8 week outage on each unit 

Detailed Engineering 

in the following disciplines:

•	 Structural

•	 Mechanical

•	 Electrical

•	 Civil

Fabrication and Erection Services:

•	 ESP Fabrication

•	 Field Technical Support

•	 Mechanical Construction

•	 Insulation Installation

•	 Electrical Installation

Performance Guarantee:

•	 Emissions guarantee: 0.015 lb/mmBTU Inlet Gas Flow: 3,706,000 ACFM at 350F

per unit

CASE HISTORIES
Air Pollution Control Systems: Parts and Service Guide 51

Climax Molybdenum, Inc.

2598 Hwy 61

Fort Madison, IA 52627

Scope of Work:

Southern Environmental, Inc., provided detail design engineering, material supply, 

fabrication, construction supervision, and start-up services for two FRP casing upflow

Membrane Wet ESPs. The units are in series and are collecting primarily Sulfuric Acid mist.

Application:

•	 Molybdenum Roaster Off-Gas Sulfuric 

Acid Mist Collection

Project Duration:

•	 1st Materials PO Received: 2/12/08

•	 1st Unit online: 11/6/08

•	 2nd Materials PO Received: 6/17/09

•	 2nd Unit Online: 1/29/10

Detailed Engineering 

in the following disciplines:

•	 Structural

•	 Mechanical

•	 Electrical

•	 Civil

Fabrication and Erection Services:

•	 ESP Fabrication

•	 Field Technical Support

•	 Insulation Installation

•	 Electrical Installation

Performance Guarantee

•	 H2S04 outlet loading <10ppmv wet Inlet

Gas Flow: 48,500 ACFM

CASE HISTORIES
52 Southern Environmental, Inc.

Duke Power Company

Marshall Steam Station

8320 East Hwy 150

Terrell, NC 28682

Scope of Work:

Southern Environmental, Inc. provided detailed 

engineering, material supply, fabrication, 

construction management, a 1/12 scale physical 

model study, electrical wiring, foundation, 

field construction, insulation and lagging,

painting and start-up services for the Marshall 

Steam Station Unit #3 & Unit #4 Electrostatic 

Precipitator Project Replacement.

The new precipitator is upstream of a new 

FGD. The unique construction approach allowed 

for the addition of a future SCR to be located 

upstream of the ESP and reduced projected 

outage time by 50%. Application:

•	 2 - 700 MW Coal Fired Power Boiler Unit

#3 & #4

Project Duration:

•	 PO Received: October 2004

•	 Mobilize: April 2005

•	 Demobilize: May 2007

•	 12 week outage 

Detailed Engineering 

in the following Disciplines:

•	 Civil Engineering

•	 Structural Engineering

•	 Mechanical Engineering

•	 Electrical Engineering

•	 1/12th Scale Physical Model 

Study

Fabrication and Erection Services: 

•	 Caisson Installation 

•	 Structural Steel Fabrication and Erection 

•	 ESP Fabrication and Erection 

•	 Electrical Construction 

•	 Ductwork Fabrication and Erection 

•	 Project Management 

•	 Site Management 

•	 Insulation and Lagging

•	 Painting

•	 Lead Abatement

Performance Guarantee

•	 SEI provided a broad range of guarantees for twenty-five coals. Outlet Emissions: Ranging between 0.04 #/mmBtu

and 0.05 #/mmBtu Opacities: Ranging

between 12% Opacity and 10% Opacity

Inlet Gas Flow: 2,512,000 ACFM at 320 F

CASE HISTORIES
Air Pollution Control Systems: Parts and Service Guide 53

Associated Electric Cooperative, Inc.

Thomas Hill Energy Center

5693 Hwy F

Clifton Hill, MO 65244

Scope of Work:

Southern Environmental, Inc. provided detailed engineering, material supply, fabrication, 

construction technical assistance and start-up services. This project was unique in 

the approach taken by making the ESP modular in design. This approach allowed for 

the modules to be constructed with the unit still online. The ESP was then shutdown, 

demolished and the modules were set individually making a shorter outage time possible.

Application:

•	 Unit #3 - 715 MW Coal Fired Power Boiler

Project Duration:

•	 Materials PO Received: 7/27/06

•	 Deliveries Completed: 09/10/07

•	 Startup: 02/28/08

Detailed Engineering in the 

following Disciplines

•	 Mechanical

•	 Electrical

•	 Structural

•	 Civil

•	 Flue Gas Conditioning

•	 Gas Flow Modeling

Fabrication and Erection Design Concepts

•	 Complete pre-outage module assembly

•	 Pre-wired modules for quick installation

•	 Unique connection design at nozzles to save 

structural steel

Performance Guarantee

•	 SEI Guaranteed Efficiency with one field out

of service at: 0.055 lb/MBtu and 11.5%

opacity Inlet Gas Flow: 1,357,500

ACFM at 313 F

CASE HISTORIES

75 Ton Module Lift
54 Southern Environmental, Inc.

Duke Power Company

Cliffside Steam Station

573 Duke Power Road

Cliffside, North Carolina 28114

Scope of Work:

Southern Environmental, Inc. provided detailed engineering, material supply, fabrication, 

construction management, a 1/12 scale physical model study, electrical wiring, foundation, 

field construction, insulation and lagging, painting and start-up services for the Cliffside Unit

#5 Electrostatic Precipitator Project Rebuild. The rehabilitated precipitator is downstream of 

a new SCR.

Phase I consisted of rehabilitating the inlet Chevron duct including stiffening for - 32 inwc 

pressure, roof replacement, and structural penetrations for SCR columns. In Phase II 

the existing precipitator was retrofitted with new internals utilizing customized SEI/ELEX

rigid discharge electrodes and Opzel collecting plates. The lower 8’ of the existing twentyfour hoppers were also replaced. The existing casing was stiffened for increased pressure 

requirements added by the SCR. A new SEI outlet field, including foundations, support

steel, casing, hoppers and Chevron outlet plenum, was added to both precipitator casings. 

The precipitator was re-sectionalized and new transformers, electromagnetic rappers and 

controls were added for increased performance.

Application:

•	 592 MW Coal Fired Power Boiler

Project Duration:

•	 PO Received: January 2001

•	 Phase I: Inlet Duct Rehabilitation

Mobilize: March 2001

•	 Demobilize: May 2001 - Five week

outage

•	 Phase II: Electrostatic Precipitator

Rehabilitation Mobilize: October 2002

•	 Demobilize: May 2002 - Eight week

outage

Performance Guarantee:

•	 SEI provided a broad range of guarantees for twenty-two coals

•	 ESP Efficiency: 99.7% at 15% opacity and at 10% opacity depending upon fuel

•	 Inlet Gas Flow: 1,950,000 ACFM at 280°F

CASE HISTORIES
Air Pollution Control Systems: Parts and Service Guide 55

CASE HISTORIES

DuPont Washington Works

8480 DuPont Road

Washington, WV 26181

Scope of Work:

With the coming demands of the Boiler MACT

requirements, and the baghouses showing their 

age, DuPont decided to implement a major 

revision and upgrade of the entire power house 

air pollution control system. Two of the existing 

baghouses were retained, but one was ducted to 

a different (previously uncontrolled) boiler, two

baghouses were replaced, and a new baghouse 

was added to replace the re-ducted system. All systems included individual lime injection

systems. 

One of the challenges of the project was to fit the new larger baghouse systems in the

space available and also use the existing support steel and foundations as the area is quite 

congested and has significant underground utilities. The design chosen included three

baghouse systems under a common penthouse. The penthouse incorporated a bridge 

crane to remove the baghouse top lids. This crane also can be used to bring material to the 

top of the baghouse from grade through an open area at the end of one of the baghouses.

Two lime silos were supplied with five lime feed and transfer systems to the five boilers. 

The lime feed systems are set up with crossover capability to provide operational flexibility.

Scope of Supply:

•	 Three new baghouse systems totaling eighteen modules

•	 Common penthouse with bridge crane to service all three baghouse systems

•	 Inlet and outlet manifolds for new baghouse systems

•	 Inlet and outlet isolation valves for new baghouse modules

•	 Two lime silos

•	 Five lime feed and conveying systems

•	 Sorbent injection systems for new and existing baghouses

•	 PLC based controls for lime systems

•	 Building to house lime blowers and controls

Project Duration:

•	 System upgrade ordered:	 August 2006

•	 Baghouse modules shipped:	 July 2007

•	 Boiler 4 operation:	 November 2007

•	 Boiler 5 operation:	 October 2007

•	 Boiler 6 operation:	 February 2008
56 Southern Environmental, Inc.

CASE HISTORIES

Kimberly Clark (Scott Paper)

2600 Federal Avenue

Everett, WA 98201

Scope of Work

The boiler location is in the middle of an 

aging plant and severe space limitations had 

dictated that an unconventional ductwork 

layout be used on the original system. 

With the new boiler replacement, there 

were still many interferences, and any 

significant duct and manifold revisions would

require excessive down time. This was not 

acceptable, and the new ductwork design 

had to accommodate the site limitations. 

A significant contract responsibility was to

perform a scale model study of the entire 

system from the inlet duct connection at 

the boiler discharge, through the manifolds, 

baghouse modules, fan and stack discharge.

The baghouse system size was increased by adding two modules, and changing the current 

bag and cage design to increase the cloth area in each module. The woven fiberglass bags

were replaced with a unique felted bag that can operate at a higher air-to-cloth ratio and 

still meet the new, much more stringent emission limitations. 

Scope of Supply

•	 Scale model study for flue gas distribution and pressure drop determination

•	 New baghouse modules with pulse jet bag cleaning and hopper accessories

•	 Inlet and outlet isolation valves for new modules

•	 Modifications to system ductwork and manifolds, penthouse, access and structural to

accommodate the new modules

•	 Complete replacement of the existing bags and cages

•	 Construction: mechanical erection, field piping and insulation

Project Duration:

•	 Original system start-up:	April 1979

•	 System expansion ordered: December 1993

•	 Model study complete: July 1994

•	 Construction start:	March 1995

•	 Start operation: July 1995
ONENTS MAINTENANCE REBUILD SERVICES NEW 

PITATORWET ELECTROSTATIC PRECIPITATORFABRIC F

LD SERVICES NEW UNITS TURN KEY INSTALLATIONS 

PITATOR FABRIC FILTER/BAGHOUSE DESIGN COMP

KEY INSTALLATIONS DRY ELECTROSTATIC PRECIPITA

OUSE DESIGN COMPONENTS MAINTENANCE REBU

ELECTROSTATIC PRECIPITATOR WET ELECTROSTAT

ONENTS MAINTENANCE REBUILD SERVICES NEW 

PITATORWET ELECTROSTATIC PRECIPITATORFABRIC F

LD SERVICES NEW UNITS TURN KEY INSTALLATIONS 

PITATOR FABRIC FILTER/BAGHOUSE DESIGN COMP

KEY INSTALLATIONS DRY ELECTROSTATIC PRECIPITA

OUSE DESIGN COMPONENTS MAINTENANCE REBU

ELECTROSTATIC PRECIPITATOR WET ELECTROSTAT

ONENTS MAINTENANCE REBUILD SERVICES NEW 

PITATORWET ELECTROSTATIC PRECIPITATORFABRIC F

LD SERVICES NEW UNITS TURN KEY INSTALLATIONS 

PITATOR FABRIC FILTER/BAGHOUSE DESIGN COMP

KEY INSTALLATIONS DRY ELECTROSTATIC PRECIPITA

OUSE DESIGN COMPONENTS MAINTENANCE REBU

ELECTROSTATIC PRECIPITATOR WET ELECTROSTAT

ONENTS MAINTENANCE REBUILD SERVICES NEW 

PITATOR WET ELECTROSTATIC PRECIPITATOR 

TENANCE REBUILD SERVICES NEW UNITS TURN K

LECTROSTATIC PRECIPITATOR FABRIC FILTER/BAGH

CES NEW UNITS TURN KEY INSTALLATIONS DR

PITATOR FABRIC FILTER/BAGHOUSE DESIGN COMP

KEY INSTALLATIONS DRY ELECTROSTATIC PRECIPITA

OUSE DESIGN COMPONENTS MAINTENANCE REBU

Corporate Headquarters

6690 West Nine Mile Road

Pensacola, FL 32526

850-944-4475

apcsales@sei-group.com

www.sei-group.com

Fabric Filter Engineering Office

921 Eastwind Drive, Suite 115

Westerville, OH 43081

614-259-6505

apcsales@sei-group.com

www.sei-group.com