United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S8-85/024 i Nov. 1985
&ERA Project Summary
Lime/Limestone Flue Gas
Desulfurization Inspection and
Performance Evaluation Manual
E. R. Kirshnan, R. S. McKibben, M. T. Melia, and B. A. Laseke
This manual on wet nonregenerable
lime/limestone flue gas desulfurization
(FGD) systems is intended to guide
Federal and State regulatory personnel
concerned with the inspection and
permitting of FGD systems for coal-
fired steam electric generators in the
U.S. The manual is structured as a
"working document" for someone who
periodically inspects power plants to
ensure compliance with emission stand-
ards. Orientation material in the manual
on the design, operating, and perform-
ance characteristics of FGD systems
may also be useful to the environmental
regulatory agency permitter. With its
goal of facilitating the systematic in-
spection of an FGD system to determine
the system's present and probable
future compliance status, the manual
limits process theory to a necessary
minimum and makes ample use of
charts, checklists, and simplified dia-
grams in providing important guidelines
and recommendations.
Following the introductory section
defining its purpose, approach, and
scope, the manual contains sections on
lime/limestone technology, perform-
ance monitoring, inspection methods
and procedures, performance evalua-
tion and problem diagnosis/correction,
operation and maintenance, and safety.
Appendices provide supplementary
reference material, definitions of FGD
terms, calculation sheets, and example
checklists, the latter two for use by
someone inspecting a plant.
This Project Summary was developed
by EPA's Air and Energy Engineering
Research Laboratory. Research Triangle
Park, NC. to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Purpose
The purpose of the manual is to guide
Federal and State environmental regu-
latory personnel involved in the inspection
and permitting of flue gas desulfurization
(FGD) systems for electric utility coal-
fired steam generators (boilers) in the
U.S.
The primary intended audience of the
manual is the field inspector directly
involved in the inspection of operational,
FGD-equipped, coal-fired, utility boilers.
For the purposes of the manual, the field
inspector is defined as the individual who
periodically inspects power plants to en-
sure compliance with emission standards.
The scope of the inspector's responsibil ity
ranges from confirmation of existing
status reports to anticipation of future
compliance status (i.e., avoidance of
potential noncompliance episodes).
A secondary intended audience of the
manual is the environmental regulatory
agency permitter, the individual who
reviews permit applications for new
capacity in accordance with adherence to
environmental regulations and emission
standards. Although the permitter is not
specifically "targeted" in the manual,
pertinent orientation material is present-
ed on the design, operating, and perform-
ance characteristics of FGD systems.
Approach
The philosophy adopted for the prepa-
ration of this manual is unique in compar-
ison to other FGD technology manuals.
-------
As stated above, the intended audience is
environmental regulatory personnel.
Other similar manuals generally define
their intended audience as the owner/
operator utility, architect-engineer, re-
search firm, and/or technology investiga-
tor. This manual, for the first time,
addresses solely the needs of environ-
mental regulatory agency personnel.
Another unique feature of the manual
is its intended use. The manual is struc-
tured as a "tool," or working document,
which will accompany the inspector on
each plant inspection. This contrasts to
the use of other similar manuals which
are often read and then filed away for
possible future reference. To adequately
serve as a working document, two major
objectives must be met in the organization
of the material. First, the document must
provide practical information tailored to
its intended use; e.g., the systematic
inspection of an FGD system to determine
present and future compliance status.
This requires that information on process
theory be limited to a necessary minimum.
Secondly, the information must be pre-
sented in a "user-friendly" format to
encourage its use. This is accomplished
by nomographs, checklists, matrices,
simplified diagrams, cross-referencing
and indexing of textual information, and
presenting important guidelines and rec-
ommendations in a conspicuous fashion.
A final unique feature of the manual is
its use for the interpretation of sulfur
dioxide (802) excess emission reports. If
an FGD-equipped boiler is a source of
frequent S02 excess emission reporting,
the manual will provide guidelines to
determine the cause and to evaluate the
remedial actions taken by the plant
operator. If an FGD-equipped boiler is a
source of infrequent S02 excess emission
reporting, the manual will provide guide-
lines to identify the contributing factors
that are associated with this situation.
Scope and Content
FGD systems are generally the last
pieces of equipment to handle the boiler
flue gas before it reaches the stack. In
lime/limestone slurry processes, S02 in
the flue gas stream is removed with the
aid of dilute limestone or lime slurries.
The treated flue gas is cooled and satu-
rated with moisture in the process. A
thorough description of the processes is
presented in Section 2 of the manual.
The FGD technology addressed in this
manual is limitedtotail-end, "wet" lime/
limestone slurry processes, excluding:
• all tail-end processes that do not use
calcium-based (lime/limestone) addi-
tives as the SO2reactant (e.g., sodium/
calcium [dual or double alkali]), so-
dium/thermal regeneration [Wellman-
Lord], magnesium oxide [Mag-Ox], and
sodium [once-through soda ash, so-
dium hydroxide, trona, nahcolite]).
• all tail-end processes that do not
completely saturate the flue gas during
treatment, known as "dry scrubbing"
(spray drying, dry sorbent injection).
• precombustion and in-situ (combus-
tion) SO2 control techniques which
may involve the use of calcium alkali
additives (e.g., limestone injection
multistage burner [LIMB], lime furnace
injection).
The rationale for emphasizing lime/
limestone slurry processes is based on
their widespread use in the power in-
dustry due to their level of process
development and economics. Since the
early application of FGD to control SOa
emissions from boiler flue gas, there has
been pronounced preference for lime/
limestone slurry processes. Presently,
plants equipped with FGD systems using
lime or limestone slurry represent over
80 percent of the electric generating
capacity with emissions controlled by
FGD. A perspective of the historical and
projected future application of lime/lime-
stone slurry processes is illustrated in
Figure 1 which shows the installed
capacity controlled by lime/limestone
120
110\-
100\-
90
CD
u
I
Cj
s
!
s
CD
80
70
60
50
40
30
20
10
Actual
. __ Projected
/
/H
//
*»v
^ /
*v
72 74 76
78 80 82 84 86 88 90 92
Year
Figure 1. Lime/limestone FGD capacity and total FGD-controlled capacity through 1992
(totals reflect end-of-year values).
-------
slurry processes as a function of the
capacity controlled by all processes.
Detailed cost studies indicate that both
the capital and the annual costs are
generally less than those of other FGD
processes. Additionally, the on-line ex-
perience of commercial systems at utility
plants has generated a wealth of opera-
tional data which are being used to
enhance system reliability. Advances in
waste disposal technology (e.g., forced
oxidation to produce more easily dewater-
ed calcium sulfate) have enabled utility
operators to reduce the volume of waste
for disposal as well as improving its
handling and disposal properties. Ad-
vances in process chemistry (e.g., mag-
nesium salts and organic acid additives)
have enabled operators to improve per-
formance with respect to SO2 removal,
process chemistry, service time, and cost
effectiveness. With continuing techno-
logical advances and increasingly wider
utilization, lime/limestone slurry process-
es are considered the major means of
compliance with New Source Perform-
ance Standards promulgated by the
USEPA for control of SO2 emissions from
power plants.
The scope of the manual is the complete
battery limits of the entire FGD process,
from the inlet gas stream to the final
waste disposal site. All operations in
between are examined, including: gas
handling and treatment, reagent prepara-
tion and feed, and waste solids handling
and disposal. Moreover, operations and
factors that influence the FGD process
envelope are considered, including: coal
characteristics and consumption, boiler
design and operation, and paniculate
emissions control and operation.
Organization of the Manual
The manual is structured to be a
constant companion to the environmental
regulatory agency inspector of FGD-
equipped, coal-fired, utility boilers. Sec-
tion 1 follows the format of this Summary.
Section 2, Lime/Limestone FGD Tech-
nology, discusses: (1) pertinent environ-
mental regulations; (2) coal properties
and flue gas characteristics; (3) basic
principles of lime/limestone slurry pro-
cesses; (4) design configurations; and (5)
operation and maintenance (O&M) con-
siderations.
Section 3, Performance Monitoring,
discusses a major element in the O&M
activities of every lime/limestone slurry
FGD system. Monitoring the FGD system
is required to demonstrate compliance
with applicable standards and that the
system meets the vendor performance
guarantees. Additionally, routine moni-
toring can identify potential operating
problems before they significantly impact
the performance of the system and/or
the generating unit. This section is de-
voted to lime/limestone slurry FGD sys-
tem performance indicators and their
measurement. Addressed in this section
are the instrumentation systems that
measure process parameters, manual
testing and continuous emission monitor-
ing methods used for emission measure-
ments, and recordkeeping practices of
the operator utility. This information is
presented from the perspective of the
agency inspector; e.g., what monitoring
techniques will yield what kinds of data,
how are these data recorded and logged,
and how to interpret these data in terms
of SOz compliance status.
Section 4, Inspection Methods and
Procedures, gives detailed procedures
and guidelines for the inspection of lime/
limestone slurry FGD systems. The objec-
tive of this section is to assist the agency
inspector in examining the FGD system,
looking first for telltale signs that might
suggest misrepresentations of emissions
such as faulty monitors or leakage in or
out of ducts, and looking secondly for
factors in addition to S02 removal •effi-
ciency that suggest poor reliability of the
FGD system. If excess emissions are
reported, this section guides the inspector
in collecting information for the deter-
mination of causes for the problem and
the assessment of remedial action(s)
taken by the utility. When no excess
emissions are reported, suggested pro-
cedures allow the inspector to assess the
preventive actions taken by the utility. It is
important that the inspector make specific
observations and record pertinent data in
order to make intelligent decisions for
resolving compliance problems or pro-
cessing variance requests.
The information in this section is
presented in a practical fashion that facil-
itates comprehension by regional/state
agency personnel; theoretical principles
underlying the inspection procedures are
not discussed.
The section begins with a brief discus-
sion of inspection procedures for the
overall plant, followed by detailed inspec-
tion procedures addressed by equipment
area and equipment items in the order
presented in Section 2. Inspection pro-
cedures for each equipment item include
an inspection checklist, an illustration
(where applicable) showing the relative
sizes of the associated components, and
brief supporting text. Performance param-
eters addressed in the equipment inspec-
tion checklists are classified under three
categories (observation, process, and
operation and maintenance) to facilitate
the interpretation and evaluation of data
obtained during inspections. The various
checklists presented in this section are
compiled in Appendix C.
Section 5, Performance Evaluation and
Problem Diagnosis/Correction, describes
guidelines that can be used by the field
inspector to interpret FGD system per-
formance data with respect to present
and future compliance status. The guide-
lines presented are "independent" in that
they are designed to assist the field
inspector irrespective of performance
interpretation or "biasing" by the plant
operator. The guidelines are designed to
be used in both immediate and long-term
performance evaluations. The latter con-
sideration is important in that an FGD
system may yield performance data indi-
cating compliance at the time of the
inspection; however, process data may
indicate the existence of problems which
will jeopardize future compliance status.
This section is a continuation of Section
3 (which describes lime/limestone slurry
FGD performance indicators and their
measurement) and Section 4 (which
describes lime/limestone slurry FGD
inspection methods and procedures). In
this section the sources of data available
to the field inspector are described, as
well as the "form" these sources take.
Techniques are described that are avail-
able to aid the field inspector in per-
formance evaluation. Cause-and-effect
problem relationships and corrective
measures are identified using simplified
sequence diagrams. Finally, followup
procedures are presented that can verify
the success of the corrective measures
taken.
As in Section 4, the information pre-
sented in this section is organized in
accordance with the equipment areas
and subsystems identified in Section 2.
Section 6, Model O&M Plan, highlights
a model O&M plan for lime/limestone
slurry FGD systems. This section intro-
duces the field inspector to the elements
of an "idealized" O&M plan which the
field inspector can use as a benchmark
from which to evaluate (compare) actual
FGD systems. "Idealized," in this context,
refers to practices that are determined to
be "preferable" based upon their suc-
cessful application in specific systems
throughout the industry.
This section is a continuation of the
material introduced in Sections 2 and 5. It
addresses the operator utility's manage-
-------
ment and staff at both the corporate and
plant levels. Operating and maintenance
manuals are described, complete with
suggested outlines. Troubleshooting tech-
niques are described in terms of an
organized multiphase program. Necessary
spare parts are described for inventories
of shelf spares. The work order system is
described in terms of its importance for
monitoring O&M response. Computerized
tracking is discussed as a necessary
function to store, retrieve, and analyze
the current and projected status of FGD
performance.
Section 7, Safety, discusses the safety
of agency personnel during field inspec-
tions. The field inspector should take
adequate precautions to guard against:
(1) inhalation of toxic gases; (2) skin
irritation and/or chemical burns; and (3)
exposure to fugitive dust. In addition,
normal industrial safety practices should
be followed such as attention to electrical
power lines and connections, attention to
steam lines and connections, attention to
rotating equipment, and protection
against falling objects. During an FGD
inspection, many of these concerns are
simultaneous and can result in potentially
serious injuries to the inspection person-
nel. Familiarization with safety proce-
dures and use of safety equipment can
result in inspections being performed
safely without risk of injury.
This section discusses many of the
potential hazards and addresses proper
safety procedures. Further information
concerning safety precautions/consider-
ations can be found in specific vendor
equipment O&M manuals for the FGD
systems and subsystems, Occupational
Safety and Health Administration (OSHA)
publications, and National Institute for
Occupational Safety and Health (NIOSH)
publications.
The appendices consist of supplemen-
tary reference material: definitions of FGD
terminology (Appendix A), calculation
sheets (Appendix B), and example check-
lists (Appendix C) which will be used by
the inspector during a plant inspection.
The inspector may wish to reproduce and
make several copies of the checklists and
keep them separate for the purpose of
conducting an inspection. The more ex-
perienced inspector may be able to tour
the facility without carrying the manual.
E. Kirshnan. R. McKibben. M. Melia. andB. Laseke are with PEI Associates, Inc..
Cincinnati, OH 45246-0100.
Theodore G. Brna is the EPA Project Officer (see below).
The complete report, entitled "Lime/Limestone Flue Gas Desulfurization
Inspection and Performance Evaluation Manual," (Order No. PB 86-107
398/AS; Cost: $28.95, subject to change} 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, NC27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
N A'>..
Official Business
Penalty for Private Use $300
EPA/600/S8-85/024
0000329 PS
SGENCY
------- |