United States Air and Energy Engineering

Environmental Protection Research Laboratory

Agency Research Triangle Park, NC 27711

E AP Project Summary

Research and Development EPA/600/SR-95/015 February 1995

tory research, pilot-scale tests, and field

demonstrations on technologies for reduction of SO2 emissions from fossil fuel combustion. This symposium was held in Boston, MA, August 24-27, 1993. The proceedings from the symposium are available in four volumes, covering over 100

papers in 13 technical sessions:

Session Subject Area

1 Clean Air Act Regulatory Strategies

2 Phase I Designs

3A Additives for High Efficiency

FGD

3B Materials for FGD

4A Clean Coal Demonstrations

4B Applied Research

5A Dry FGD Technologies

5B Wet FGD Process Issues

(Part I)

6A Air Toxics Removal in FGD Systems

6B Wet FGD Process Issues

(Part II)

7 Poster Papers

8A Emerging Technologies

8B Waste Utilization and Disposal

Clean Air Act Regulatory

Strategies

Four papers comprised the introductory

session, Session 1, to the symposium.

The first paper presented the potential

synergies and conflicts that have arisen

between the acid rain provisions of the

Clean Air Act Amendments of 1990

(CAAA) and the other titles involving hazardous air pollutants. These conflicts may

lead to inefficient decisions by utilities as

their risk-averse posture and the structure

of the CAAA discourage integrated deciProceedings: 1993 SO2

 Control

Symposium

Brian K. Gullett

This report compiles over 100 papers presented at the 1993 Sulfur Dioxide (SO2) Control Symposium held in

Boston, MA, August 24-27, 1993. Papers in this symposium covered a

wide range of topics: industry’s strategies for dealing with the Clean Air

Act Amendments of 1990, including

Phase I strategies, the emission allowance trading system, and retrofit

construction; additives, materials, and

operating issues for wet flue gas desulfurization (FGD); clean coal demonstration programs; the effect of FGD

systems on air toxics; dry FGD technologies of spray drying and furnace

sorbent injection; applied SO2 control research results and emerging

acid rain control technologies; and

waste disposal issues. Papers covered results obtained from full-scale

demonstration/operation to pilot- and

bench-scale work.

This Project Summary was developed

by EPA’s Air and Energy Engineering

Research Laboratory, Research Triangle Park, NC, to highlight key topics

on SO2 control. Full documentation of

the report of the same title is available

(see Project Report ordering information at back).

Introduction

The symposium was jointly sponsored

by the Air and Energy Engineering Research Laboratory, U.S. Environmental

Protection Agency (AEERL/EPA), the Electric Power Research Institute (EPRI), and

the U.S. Department of Energy (DOE). It

is held approximately every 18 months to

transfer technical information from labora-
2

sions in reaching the goals of all titles of

the CAAA. Another paper presented a

model based on four utilities’ data that

estimates key factors regarding the SO2

allowance trading system. An interactive

multidimensional analysis for risk assessment was described by 1) a risk-based

methodology for setting detection limits

for field testing and 2) a framework for

analyzing health risks from mercury emissions. The last paper of the session described the Clean Air Technology,

WorkstationTM*, a tool for determining the

economics of methods for systemwide

emission reduction. This system allows

commercial and emerging technologies to

be evaluated and allows users to vary

system parameters of unit configurations,

technologies, and fuels.

Phase I Designs

This session (Session 2) contained eight

papers that discussed system designs for

meeting Phase I requirements of the

CAAA. Wet lime or limestone FGD systems were or will be installed or retrofitted

by Indiana Power & Light Company, Tennessee Valley Authority (TVA), the

Conemaugh Station owners, Kentucky

Utilities (with fuel switching), Henderson

Municipal Power and Light, Navajo Generating Station, and PSI Energy Inc. Guidelines for economics decisions, design, and

retrofit concerns for duct injection systems

were also presented.

Additives for High Efficiency

FGD

Wet FGD systems’ SO2 removal can

often be improved by use of additives. In

this session (Session 3A), papers were

presented discussing the effect of organic

acid additives (dibasic acid, formate) on

pilot- and full-scale facilities both in terms

of SO2 removal and solids disposal properties. A model was developed and tied

into EPRI’s FGD Process Integration and

Simulation Model ( FGDPRISM) that estimates consumption rates of dibasic acid

and formate ion in wet limestone FGD

systems. A new ammonia-based process

on a pilot plant using ammonium sulfate

liquor for SO2 absorption was described.

The process produces high purity ammonium sulfate crystals with market value.

Materials for FGD

Eight papers in Session 3B covered

topics related to materials of construction

for FGD systems. Topics covered included

economics, comparative technical performance, and design considerations. Structural materials and coatings used in ducts,

towers, stacks, sumps, tanks, and pumps

were discussed for a PSI Energy, Inc.,

unit. An EPRI research program investigating a wide variety of construction materials for FGD systems was presented

with feedback from operating FGD plants.

Finally, a failure analysis of FGD materials from 33 different investigations was

reported, showing that 31% of failures resulted from quality control breakdown and

27% resulted from inadequate material

selection.

Clean Coal Demonstrations

Results from DOE’s Clean Coal Technology program were presented for eight

implementations in Session 4A. Bechtel’s

Confined Zone Dispersion Technology,

Pure Air’s demonstration at the Bailly Generating Station, Ohio Edison’s SNOX technology, the Passamaquoddy Technology,

L.P. potassium or sodium process,

Babcock & Wilcox’s SOx -NOx -ROx BOxTM

(SNRB) process, the Chiyoda CT-121

project at Georgia Power’s Plant Yates

(Unit #1), Tampella Power Corporation’s

LIFAC sorbent injection technology, and

the Air Pol, Inc., demonstration of Gas

Suspension Absorption FGD were all discussed in papers from this session.

Applied Research

This session (4B) covered research-oriented topics in eight papers. A paper from

University of Lund, Sweden, reviewed the

limits and potential of furnace sorbent injection, finding that small particles (< 3 m)

with sufficient mixing can achieve 95%

SO2 removal at a residence time of 2s

and at a calcium/sulfur ratio of 2/1. The

application of gas-phase ionic chemistry

for pollution control was discussed, including a look at the equipment, experimental results, applications, and costs.

Work from the Universidad de Cantabria,

Spain, was presented on kinetic modeling

of the low temperature, humidified reaction of hydrated lime in an FGD system.

Production of the ADVAnced siliCATE

(ADVACATE) sorbent utilizing fly ash was

examined, where researchers at the University of Texas at Austin related batchand flow-reactor-derived sorbents and

found that grinding the ash dramatically

increased the reaction rate. Researchers

at Lawrence Berkeley Laboratory presented development of a catalyst capable

of >90% sulfur yield for a process that

would catalytically reduce SO2 to elemental sulfur. The University of Kentucky and

TVA presented results on pilot scale tests

of a circulating bed absorption system,

covering effects of stoichiometry, gas temperature, fuel chloride, gas residence time,

and total sulfur capture. The University of

Cincinnati’s work on sorbents for spray

dryers slurried fly ashes with quicklime

and determined reactivity, suggesting that

the compressive strength of the material

may be a reactivity indicator. Other work

at the university studied the economizer

temperature reactivity of injected calcium

hydroxide and dolomitic hydroxide sorbents.

Dry FGD Technologies

Several varieties of dry sorbent systems for FGD were covered in eight papers in Session 5A. Furnace sorbent injection (FSI) processes were discussed in

papers on full-scale results. A paper by

Combustion Engineering, Inc., Virginia

Power Company (VPC), and EPA discussed optimization (in progress) of the

combined SO2/NOx demonstration at

VPC’s Yorktown Power Station. A combined SO2/NOx retrofit program at the

Bastardo power plant in Italy was discussed. Combining gas reburning with

FSI (GR-SI), a Clean Coal Technology

Round I demonstration project was discussed, along with results from an earlier

project. An overview of supported sorbents

technology (magnesia or lime coated on

vermiculite or perlite substrates) and demonstration results was presented. Pilotscale work on spray dryers with fabric

filters achieving 95% SO2 removal was

discussed for medium- and high-sulfur

coals. The final three papers presented

commercial operating results for dry FGD

technologies in Canada, Japan, and Germany.

Wet FGD Process Issues (Part I)

This session (5B) contained seven papers on various issues related to wet FGD

processes. Several papers compared and

discussed inhibited and fully oxidized operating modes of wet lime and limestone

FGD systems. Topics of operating guidelines for cyclic FGD systems, high efficiency pilot plant results, control of a limestone grind circuit, design of mist eliminators, and economics of chloride removal

were covered.

Air Toxics Removal in FGD

Systems

 With the passage of the CAAA, control

of toxic or hazardous air pollutant emissions may become an issue of concern

for facilities burning fossil fuels. Eight papers in this session (6A) covered various

topics related to air toxics control and the

interrelationship with control of SO2. EPRI’s

program on reviewing air toxics literature

_________________________

* Mention of trade names or commercial products does

not constitute endorsement or recommendation for

use.
3

coupled with its pilot wet FGD tests for

mercury removal were presented. Other

topics included the ability of available control technologies to deal with organic and

metallic pollutants; performance of three

spray dryer pilot plants at removal of mercury, selenium, and boron; reduction of

submicrometer metal emissions of arsenic,

selenium, mercury, and antimony by FSI;

performance of SNRB versus electrostatic

precipitators for collection of air toxics;

effect of a semi-dry FGD system in Germany to remove heavy metals; and the

use of Fourier Transform Infrared technology as a continuous emission monitor.

The session closed with a summary of

research needs in air toxics determined

from a workshop sponsored by EPRI and

DOE.

Wet FGD Process Issues (Part

II)

This session (6B) continued papers on

this topic started in Session 5B. Seven

papers were presented, covering development of a plume opacity engineering

workbook, reduction of sulfur trioxide by

sorbent injection to lower plume opacity,

optimization of the FGD system at the

Bruce Mansfield Plant, the magnesiumenhanced lime scrubber at the Zimmer

Generating Station, development of a clear

liquor scrubbing process, development of

a test facility for studying wet scrubber

fluid mechanics, and an update on

FGDPRISM. The last paper in this session discussed the European view of FGD

applications and new advances and topics in flue gas cleaning systems.

Poster Papers

Session 7 included 19 papers that were

also presented as posters at a special

session. These papers covered a variety

of subjects, encompassing the major topics of the symposium. The poster papers

included a mixture of field demonstration

and pilot- and bench-scale reports on both

wet and dry FGD processes, multipollutant

control processes, foreign and domestic

authors, and modeling efforts.

Emerging Technologies

Seven papers were presented in Session 8A on developments in new FGD

processes. They included a report on a

moving limestone bed process, pilot plant

results of several new technologies,

ADVACATE studies at a TVA plant, demonstration of a sodium-based scrubber and

membrane separation for sulfur recovery,

and optimization of the Advanced Coolside

technology, which uses sorbent injection

and flue gas humidification.

Waste Utilization and Disposal

The last session of the symposium, Session 8B, included seven papers on topics

including economics of FGD waste disposal, use of FGD waste as a saleable

gypsum product, application of FGD

wastes to agricultural production, waste

stabilization, and use of FGD as a component of a landfill liner.
4

Brian K. Gullett (also the EPA Project Officer see below) is with the U.S.

Environmental Protection Agency, Research Triangle Park, NC 27711.

The complete report, entitled “Proceedings: 1993 SO2

 Control Symposium,” consists of four volumes:

Volume I (Order No. PB95-179222, Cost: $52.00, subject to change) consists of

Sessions 1, 2, 3A, and 3B.

Volume II (Order No. PB95-179230, Cost: $52.00, subject to change) consists of

Sessions 4A, 4B, and 5A.

Volume III (Order No. PB95-179248, Cost: $44.50, subject to change) consists of

Sessions 5B, 6A, and 6B.

Volume IV (Order No. PB95-179255, Cost: $61.00, subject to change) consists

of Sessions 7, 8A, and 8B.

The complete set, consisting of all four volumes, can be ordered using Order No.

PB95-179214. The cost is $178.50 (subject to change).

All documents will be available only from

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Telephone: 703-487-4650

The EPA Project Officer can be contacted at

Air and Energy Engineering Research Laboratory

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

• •

United States

Environmental Protection Agency

Center for Environmental Research Information

Cincinnati, OH 45268

EPA/600/SR-95/015

Official Business

Penalty for Private Use $300

BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35