A URS and MHIA Company

Double Contact Flow Scrubber

Advanced FGD Technology for Your Multi-pollutant Control Needs

SO2
ADVATECH formed in 2002 as a joint 

venture of URS Corporation and 

Mitsubishi Heavy Industries America 

(MHIA) to bring the unique and highly 

effective Double Contact Flow 

Scrubber (DCFS) wet FGD technology 

to the U.S. marketplace. As a jointly 

owned company, ADVATECH pairs 

MHI’s technology with the engineering, 

design, procurement, and construction 

(EPC) services of URS. 

The DCFS is unique in that the 

slurry sprayed from each nozzle contacts the flue gas twice—as it sprays 

upward and as it rains down. This 

double contact provides more 

efficient mass transfer and higher SO2 

removal per unit of L/G. ADVATECH 

offers both a Single Tower and Twin 

Tower DCFS to cost effectively achieve 

your removal requirements. The Single 

Tower DCFS is for units burning low- to 

medium-sulfur fuel, and the Twin Tower 

DCFS is for units burning medium- to 

high-sulfur fuel.

Through nearly five decades of 

experience, and years of research and 

development, MHI has continuously 

made design improvements that 

augment performance and reliability 

while driving down O&M costs. This 

has resulted in a design capable of 

achieving greater than 99% SO2

removal with 100% availability, 

regardless of boiler size and/or fuel 

sulfur content. 

Single Tower DCFS

Features Common to the DCFS

Low profile – The DCFS technology introduces 

all of the recycle spray at a single elevation, 

resulting in a shorter absorber than a 

traditional open spray tower or tray tower.

The low elevation of the spray header and lowpressure spray nozzles employed in the design 

translates into low recycle pump head, resulting 

in lower overall power consumption.

Single spray level – Since there is only 

a single elevation of spray nozzles supplied 

by a common header, the spare recycle 

pump does not require a spare spray 

header. Furthermore, the potential for 

header-to-header erosion is reduced. Since 

the spray header is always in service with 

slurry constantly raining down on it, it is 

self cleaning, resulting in decreased 

maintenance.

Efficient oxidation and agitation – The 

DCFS uses the patented Jet Air Sparger (JAS) 

technology for efficient oxidation and agitation 

of the absorber slurry. The JAS acts as an 

eductor, making use of existing recycle pump 

capacity to induce air into the absorber reaction 

tank. For low-sulfur systems, a series of JAS can 

educt enough ambient air into the process to 

eliminate the need for oxidation air blowers. 

For high-sulfur systems, smaller capacity blowers 

are required. In all instances, agitator 

requirements are minimized.

Fountain spray nozzles – Our 

proprietary nozzles have no internals and 

a large free passage (2"), making them

much less susceptible to plugging 

and erosion, longer lasting, and less 

maintenance intensive. Since the 

nozzles generate a fountain, they can be 

located close to each other and the 

absorber walls without risk of 

increased erosion from direct 

impingement. The tighter nozzle 

spacing reduces gas sneakage and 

helps to ensure high removal efficiency. 

Slurry Distribution Level

2
ADVATECH DCFS Offers:

•	The highest demonstrated 

performance worldwide

– 99.8% SO2 removal efficiency 

– Ultra-high removal through a wide 

range of SO2 concentrations 

(up to 7,800 ppm demonstrated)

•	High reliability

– 100% reliability demonstrated in 

plants operating domestically and 

internationally

•	Simple operation and maintenance 

– Forgiving to fuel fluctuations

– Easy access and maintenance

– Low power consumption

•	Attractive economics driven by:

– Superior low-cost technology

– Project and technology integration

– Optimized business structure

•	The largest installed WFGD 

experience base

– 82,000 MW worldwide

– >20,000 MW domestic

•	The largest installed base of 

tile-lined concrete absorbers

– 10,200 MW domestic

Twin Tower DCFS

Carbon Steel Inlet Duct – Flue 

gas enters the vessel at the top of the 

first tower, placing the wet-dry interface 

approximately 10 feet into the vessel. 

The nature of this design makes it 

impossible to get recycle slurry into 

the absorber inlet ductwork, thus 

avoiding the need for exotic materials of 

construction.*

Expandability – The common header 

allows for the future ability to treat 

higher-sulfur fuel or achieve higher 

removal efficiencies with minimal, 

upfront capital investment. Provisions 

can be designed into the system that 

allow for the future procurement and 

installation of recycle pumps and, if 

necessary, other equipment at a 

reasonable retrofit cost.

Stable and forgiving operation – The DCFS is designed to operate at 30 wt% 

suspended solids, twice that of competing technologies. The resulting buffer capacity 

and close proximity of nucleation sites provides for stable operation and low scaling 

potential. The DCFS is less susceptible to fluctuations in performance as a result 

of variations in gas flow rate or composition, and high removal efficiency can be 

achieved without the need for organic acid addition.

Top-mounted agitators – Adequate agitation 

and oxidation are critical to scale-free operation. 

The Twin Tower DCFS has the added advantage of 

using top-mounted agitators installed between 

the two towers, which ensures top-to-bottom 

mixing of the reaction tank slurry.*

Maintainability – The ease of access and 

minimization of internals make the DCFS the 

lowest cost-to-maintain absorber module in 

the world. There are no oxidation air spargers to 

plug, only a single spray header elevation to 

inspect and maintain, no scaffolding requirements 

to inspect the slurry nozzles, commonality of 

equipment, and easy access to all equipment. 

Spray Nozzle Fountains Jet Air Sparger (JAS) Recycle Pumps

* Feature specific to Twin Tower DCFS 3

Based upon ADVATECH and MHI experience
4

A Cost-Effective and Space Conscious Solution for Air Quality Control

ADVATECH has developed, 

standardized, and implemented a 

simplified and integrated wet FGD 

process that requires less capital 

investment and a smaller footprint 

than traditional designs. The 

Simplified DCFS, shown above, is 

designed specifically for small and 

industrial boilers, and has a total 

installed cost of nominally $200/KW.

The Simplified DCFS eliminates 

costly and, in some instances, 

maintenance-intensive capital 

equipment. Furthermore, its design is 

close coupled to minimize ductwork, 

piping, and electrical runs, as well as 

overall space requirements. Specific 

features include the following:

Pre-ground limestone

Rather than grinding limestone on 

site, pre-ground limestone is 

procured. The powdered limestone is 

directly fed to the absorber reaction 

tank to control pH, eliminating the 

ball mill, tank, agitator, and pump 

requirements associated with grinding 

limestone and handling a slurry.

Direct feed to primary dewatering

Since the DCFS is designed to 

operate at 30 wt% solids, in most 

instances only a single dewatering 

stage is required. As a result, slurry 

from the reaction tank can be directly 

fed to the locally placed belt filter 

using existing recycle pump capacity.

Integrated stack

For stack height requirements of 

approximately 300 feet or less, 

ADVATECH offers a wet FGD design in 

which the stack is mounted directly 

to the top of the absorber vessel. 

This integrated design dramatically 

reduces both footprint and capital 

cost requirements. Through the 

avoidance of a stand-alone stack, 

expensive FGD-outlet ductwork is 

eliminated, and both foundation and 

access requirements are reduced.

ADVATECH’s Simplified DCFS

Integrated Stack

>750 MW of Operating Capacity

Pre-Ground Limestone System

45,000 MW of Operating Capacity

Direct-Feed Dewatering 

23,000 MW of Operating Capacity
Fly Ash Zero Liquid Discharge

NOx Control

• SCR

• SNCR

• Low NOx Burners

Opacity/Fine PM Control

• NH3

• SBS InjectionTM

• Lime/Trona

• High Efficiency System

• Wet ESP (WESP)

PM Control

• ESP

• Fabric Filter

Acid Gas Control

• Wet FGD

Hg Control

• Fuel Additives

• Halogen Injection

• NH4Cl Injection

• Wet FGD

• PAC Injection

• ORP Control

Coal

Gypsum to Wallboard

ADVATECH takes an integrated 

approach to meeting the stringent 

emission requirements for existing 

and new plants. By combining 

proprietary MHI technologies with 

established commercial technologies, 

ADVATECH maximizes the co-benefits 

of each process component for 

achieving multi-pollutant control. As a 

result, we are able to offer sustained, 

reliable performance while minimizing 

total lifecycle cost.

The centerpiece of ADVATECH’s 

multi-pollutant control strategy is the 

DCFS. The DCFS, while highly 

efficient at removing acid gases, is 

also beneficial for controlling other 

pollutants. 

Particulate emissions can be 

further reduced by up to 95 percent 

when located downstream of an ESP. 

In tandem with a reagent injection 

process, wet ESP, or High Efficiency 

System to control acid mist, opacity 

levels can be reduced to single digits. 

The DCFS is also efficient in 

removing oxidized mercury. In combination with an SCR, halogen 

injection, PAC injection, and/or ORP 

control, 95% or greater removal of 

total mercury (from coal pile to stack) 

can be achieved. 

For plants where the wet FGD 

system needs to operate “closed 

loop” to comply with Zero Liquid 

Discharge (ZLD) requirements, 

Advatech can either design a DCFS 

where the only chloride purge is with 

the gypsum solids, or supply one of our 

proprietary ZLD technologies. Our 

Wastewater Spray Dryer (WSD) 

technology is a low-cost means of 

complying with ZLD requirements while 

still allowing operation of the wet FGD 

at economical chloride levels. With the 

WSD, the required liquid purge from the 

wet FGD process is added to a spray 

dryer installed in a slipstream that 

bypasses the air heater. The chlorides 

and other dissolved species form solid 

particulates that are removed from the 

flue gas with the fly ash in the 

particulate control device. As a result, a 

liquid purge from the plant is completely 

eliminated, as is a costly wastewater 

treatment process.

An Integrated Approach to Multi-Pollutant Control

Multi-pollutant Control

5
6

ADVATECH Domestic Experience

URS is the largest provider of 

engineering, design, construction, 

and start-up support for commercially 

available air emission controls 

systems, and provides clients with 

the appropriate technology mix and 

emissions strategy to bring them into 

regulatory compliance for the lowest 

installed and lifecycle cost.

Plant / Unit Utility Capacity Coal Sulfur S02 Removal

Absorber 

Materials

Scope of 

Work

Paradise 3 TVA 1,060 3% 98% 6% Moly / 2205 Full EPC

Gorgas 8-10 Alabama Power Company / 

Southern Company 1,021 2% 98% Stebbins EP

Bull Run 1 TVA 920 2% 98% 6% Moly / 2205 Full EPC

Hammond 1-4 Georgia Power Company /

Southern Company 800 2% 98% Stebbins EP

Harding Street 7 AES 465 3.6% 97% 6% Moly Full EPC

Kingston 1-9 TVA 2 x 755 2% 98% 2205 Full EPC

Miller 1-4 Alabama Power Company /

Southern Company 4 x 660 0.4% / 1% 98% Stebbins EP

Scherer 1-4* Georgia Power Company /

Southern Company 4 x 818 0.3% / 1.5% 98% / 96% Stebbins EP

Newton 1-2** Ameren Energy Resources 2 x 670 0.57% 98% Stebbins Full EPC

Daniel 1-2** Mississippi Power Company /

Southern Company 2 x 530 0.33% / 1.5% 98% / 96% Stebbins EP Process 

Island

 * Partially operational as of August 2011

** Not yet operational

Unrivaled Experience

 WFGD Upgrades 45,000 MW

 FGD Turnkey Systems 41,000 MW

 Domestic Wet FGD Systems >20,000 MW

 SO3 Control Systems: SBS 15,000 MW

 WESP* 4,300 MW

 High Efficiency System 7,200 MW

SCR 24,000 MW

*Located at stack inlet

URS & MHI Domestic AQCS Experience

MHI is the world’s leading supplier 

of FGD systems. The first system was 

installed in 1964 and, today, over 

82,000 MW of wet FGD technology is 

in operation on more than 214 boilers 

in 14 countries.

ADVATECH has successfully 

delivered more than 14,000 MW of 

Brownfield wet FGD capacity to the 

U.S. utility industry. The 

scope of our services 

range from engineering 

and procurement to full 

EPC, and all of our 

operating installations 

continue to 

demonstrate 

exceptional 

performance.

Installed FGD Capacity 82,000 MW

FGD Orders Since 1964 214 FGDs

FGD Domestic Experience >20,000 MW

Highest SO2 Guaranteed Removal 99.80%

Highest SO2 Removal w/o Additives 99.90%

Highest SO2 Concentration 7,800 ppm

Largest Single Absorber* 1,021 MW

Longest Time Between Outages 4 yrs

Spare Modules Installed None

Availability, Single Module 99.9% / 18 yrs

Highlights of MHI’s 

Worldwide Wet FGD Experience

* Based on flue gas volume
7

n TVA – Paradise Kentucky

1 x 1,060 MW Twin Tower DCFS Absorber

Boilers 1 x 1,060 MW

Design “S” Fuel 3.0%

Design Gas Volume, ACFM 4,028,000

Guaranteed Removal 98%

ADVATECH Scope of Supply Full EPC 

Absorber Materials 6% Moly / 2205

Award Date / Operation Date 2002 / Fall 2006

This project was the first application of the ADVATECH DCFS process in the U.S. 

and the first unit for the system-wide contract with TVA. It was a full EPC contract with balance-of-plant project scope, including the stack. At the time of its 

design, it was the largest single absorber in the world.

n TVA – Bull Run Tennessee

1 x 920 MW Twin Tower DCFS Absorber

Boilers 1 x 920 MW

Design “S” Fuel 2.0%

Design Gas Volume, ACFM 3,065,000

Guaranteed Removal 98% 

ADVATECH Scope of Supply Full EPC

Absorber Materials 6% Moly / 2205

Award Date / Operation Date 2005 / Fall 2008

This project included a full EPC contract with balance-of-plant project scope, 

including the stack. It was selected for Engineering News-Record Project of 

the Year, 2009.

n Southern Company – Gorgas Alabama Power

1 x 1,021 MW Twin Tower DCFS Absorber

Boilers 1 x 800 MW, 2 x 110 MW

Design “S” Fuel 2.0%

Design Gas Volume, ACFM 4,020,000

Guaranteed Removal 98% 

ADVATECH Scope of Supply EP Supply Process Islands 

Absorber Materials Concrete Tile Lined (Stebbins)

Award Date / Operation Date 2005 / Dec 2007

We started big. Not only was Gorgas ADVATECH’s first application of a Stebbins, 

semplate-lined, concrete absorber, but it is the largest absorber vessel in the 

world in terms of gas volume and the first application of a DCFS designed to 

treat multiple boilers.

U.S. Commercial Experience
n IPL – Harding Street Indiana

1 x 465 MW Twin Tower DCFS Absorber

Boilers 1 x 465 MW

Design “S” Fuel 3.6%

Design Gas Volume, ACFM 1,690,000

Guaranteed Removal 97% 

ADVATECH Scope of Supply Full EPC 

Absorber Materials 6% Moly

Award Date / Operation Date 2005 / Sept 2007

This full EPC contract included balance-of-plant project scope such as reagent 

receiving/prep, gypsum dewatering/loadout, and stack. Executed at a congested 

site with a tight schedule, the project required processing high-sulfur fuel with 

high SO2 removal while producing wallboard-grade gypsum.

n Southern Company – Hammond Georgia Power

1 x 800 MW Twin Tower DCFS Absorber

Boilers 3 x 125 MW, 1 x 425 MW

Design “S” Fuel 2%

Design Gas Volume, ACFM 3,026,000

Guaranteed Removal 98% 

ADVATECH Scope of Supply EP Supply Process Island and BOP

Absorber Materials Concrete Tile Lined (Stebbins)

Award Date / Operation Date 2005 / July 2008

Four boilers are treated by a single absorber module while maintaining ultra-high 

SO2 removal and producing wallboard-grade gypsum. Procurement of the 

Stebbins absorber vessel was excluded from ADVATECH’s scope of supply.

n TVA – Kingston Tennessee

2 x 755 (1,510) MW Twin Tower DCFS Absorber

Boilers 4 x 140 MW, 5 x 190 MW

Design “S” Fuel 3.0%

Design Gas Volume, ACFM 2,915,000 per Absorber

Guaranteed Removal 98%

ADVATECH Scope of Supply Full EPC 

Absorber Materials 2205

Award Date / Operation Date 2005 / Nov 2009, April 2010

This project brought the challenge of designing a system capable of processing 

flue gas from nine boilers using two twin tower DCFS alloy absorbers. The scope 

included full EPC for two process islands and all balance-of-plant requirements, 

including stack.

8
n Southern Company – Scherer Georgia Power

4 x 818 (3,272) MW Single Tower DCFS Absorber

Boilers 4 x 818 MW

Design “S” Fuel 0.3 / 1.5%

Design Gas Volume, ACFM 3,710,000 / 3,507,000

Guaranteed Removal 98% / 96%

ADVATECH Scope of Supply EP Supply Process Island 

Absorber Materials Concrete Tile Lined (Stebbins)

Award Date / Operation Date 2008 / 2010-2013

The four single-tower absorbers are designed to achieve 98% SO2 removal when 

burning low-sulfur PRB coal, while allowing future expandability to treat a higher 

sulfur fuel with minimal upfront cost and a modest cost of retrofit. Procurement 

of the Stebbins absorber vessel was excluded from ADVATECH’s scope of supply.

n Ameren Energy Resources – Newton Station Illinois

2 x 670 (1,340) MW Single Tower DCFS Absorber

Boilers 2 x 670 MW

Design “S” Fuel 0.6%

Design Gas Volume, ACFM 2,700,000

Guaranteed Removal 98%

ADVATECH Scope of Supply Full EPC 

Absorber Materials Concrete Tile Lined (Stebbins)

Award Date / Operation Date Sept 2008 / Under Construction

This project represents a full EPC contract with direct hire construction and balance-of-plant project scope, including the stack. Design features include the use 

of pre-ground limestone, gypsum dewatering, and a common pump building for 

the two absorbers.

n Southern Company – Daniel Mississippi Power

2 x 530 (1,060) MW Single Tower DCFS Absorber

Boilers 2 x 530 MW

Design “S” Fuel 0.33%

Design Gas Volume, ACFM 1,900,097

Guaranteed Removal 98%

ADVATECH Scope of Supply EP Supply Process Island 

Absorber Materials Concrete Tile Lined (Stebbins)

Award Date / Operation Date Jan 2011 / Feb & Mar 2015

The two single-tower absorbers are designed to achieve 98% SO2 removal when 

burning low-sulfur, blended coal, while allowing future expandability to treat a 

higher sulfur fuel with minimal upfront cost and a modest cost of retrofit. 

Procurement of the Stebbins absorber vessel was excluded from ADVATECH’s 

scope of supply.

n Southern Company – Miller Alabama Power

4 x 660 (2,640) MW Single Tower DCFS Absorber

Boilers 4 x 660 MW

Design “S” Fuel 0.4 / 1.0%

Design Gas Volume, ACFM 2,850,000 / 2,533,000

Guaranteed Removal 98%

ADVATECH Scope of Supply EP Supply Process Island 

Absorber Materials Concrete Tile Lined (Stebbins)

Award Date / Operation Date 2007 / 2009-2011

Named Best Coal-fired Project 2011 by Power Engineering magazine. 

The project included four single-tower DCFS to achieve 98% SO2 removal on 

Powder River Basin coal. The system uses pre-ground limestone and Jet Air 

Sparger technology (for oxidation) to produce wallboard-quality gypsum.

9
Creating and 

Preserving Value Through 

Project Integration

Project Integration









	

















	

















 











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n Technology Provider

Like most technology providers, 

ADVATECH can provide all technology 

performance requirements necessary for a 

customer to achieve regulatory compliance. Where ADVATECH differs, however, 

is through optimization of technology integration, allowing delivery of the lowest 

cost solution.

ADVATECH offers a full range of technologies for control of NOx, SO2, SO3, 

PM, Hg, and HAPs. We also offer technological solutions for Zero Liquid Discharge, 

and can optimize around any fuel and 

even provide for maximum fuel flexibility. 

n Single-Point Responsibility 

EPC Contractor

Unlike a traditional OEM, ADVATECH’s 

world-class EPC capabilities provide 

complete, seamless project and technology integration. With single-point 

responsibility, ADVATECH minimizes or 

eliminates multi-company interfaces to 

deliver a low-cost project.

Our experienced and outstanding team 

provides expertise for full program and 

project management, conceptual and 

detailed design engineering, optimized 

procurement and quality management, 

direct hire or managed subcontract 

construction, commissioning, startup, 

and tuning.

Through our wide ranging and demonstrated capabilities, we deliver certainty 

of outcome.

ADVATECH’s mission is to deliver 

certainty of outcome—something our 

customers demand and deserve. We 

believe this is best accomplished by 

integrating technology solutions with all 

other aspects of project execution. 

As a major EPC provider with a worldclass technology, ADVATECH has been 

exceptionally successful in delivering over 

14,000 MW of AQCS systems worth over 

$2B to the U.S. utility industry. Not only 

are we the lowest cost provider, we also 

meet or exceed all project parameters. 

ADVATECH achieves these results by providing a world-class superior portfolio of 

technologies, single-point EPC responsibility, and unique long-term services.

n Long-Term Service Provider

In addition to technology and project 

delivery, ADVATECH offers much more.

Our unique relationship with regulatory 

agencies (local and national) allows us to 

offer advantages in permitting support and 

system monitoring.

Our unmatched experience in process 

and system improvement, dating back to 

the 1970s, provides you with ongoing 

support as regulations evolve.

Our unprecedented R&D efforts in the 

U.S. and Japan means new technologies 

are developed and commercialized on a 

regular basis, thus providing for future 

optimization and efficiency improvements

Through these long-term services, 

certainty of outcome is ensured in the 

future.

10
The 400-MW Single Tower 

DCFS Test Facility

(MHI Mihara, Japan)

SiC spray 

nozzle

Pilot plants 

can use a 

client’s coal, limestone, and 

makeup water to simulate desired 

conditions.

100 MW absorber fluid 

dynamics model

ADVATECH, through MHI and URS, is 

strongly committed to research and 

development, and to bringing continuous 

improvements to the utility industry. 

We have large, modern research facilities 

dedicated to air pollution control. 

ADVATECH’s wet FGD system has 

evolved to a simple, reliable, and highly 

efficient single loop, double contact flow 

scrubber. Prominent technology 

improvements inlcude the single-stage 

DCFS spray header design and Jet Air 

Sparger (JAS) for gypsum oxidation. The 

JAS has no moving parts and is so 

effective at oxidation and agitation that it 

not only reduces oxidation air and 

agitator requirements, but also eliminates 

the need for blowers on units burning 

low-sulfur fuel. 

A full-featured, wet FGD pilot plant that 

can use site-specific coal, limestone, and 

water sources is available to model 

client-specific operating conditions, and 

characterize the multi-pollutants in the 

flue gas. 

Recent developments have focused on 

control of trace emissions such as sulfuric 

acid mist (H2SO4), Hg, HCl, HF, and 

selenium. URS and MHI have developed 

technologies for 90 percent or greater 

reduction of mercury emissions. URS has 

significant operating experience for the 

control of SO3 emissions with the use of 

SBS InjectionTM. When treatment takes 

place upstream of the air heater, the 

acid dew point is significantly decreased, 

paving the way for boiler efficiency 

improvements. 

ADVATECH brings the full talent and 

capabilities of MHI and URS research 

and development to the U.S. market. We 

can design our control technologies to 

account for future emissions requirements, 

providing reassurance that you can comply 

with future emissions control legislation.

Relentless Improvement
Corporate Strength and Commitment

ADVATECH combines the strength and corporate commitment of two world-class organizations – 

URS and Mitsubishi Heavy Industries – to manage, engineer, procure, and construct the optimum technology 

solutions for emerging environmental requirements. Over $35B in annual revenue stands behind ADVATECH, 

the most successful solutions provider in the industry. 

Washington Division

CERTAINTY OF OUTCOME

For more information contact:

George Sacco

Vice President Business Development 

ADVATECH

Atlanta, GA

Phone: 678.808.8841

Mobile: 770.335.3559

Email: george.sacco@urs.com

Scott Miller

Director of Engineering Technology

ADVATECH

Austin, TX

Phone: 512.419.5386

Mobile: 512.431.4790

Email: scott.d.miller@urs.com

Naoki Kojima

Vice President Commercial

ADVATECH

Austin, TX

Phone: 512.219.2369 

Mobile: 512.815.8036

Email: naoki_kojima@mhiahq.com 

www.AdvatechLLC.com

SBS Injection is a trademark of URS Corporation

The information contained herein is provided for advertising and general information 

purposes only, and does not constitute any warranties or guarantees.

Copyright © 2013 ADVATECH LLC

Certainty of outcome is what ADVATECH has delivered since 2002 through:

Superior, low-cost technologies

Exceptional single-point integrated EPC project execution

Business structure that aligns Owner and ADVATECH goals for project delivery