United States
Environmental Protection
Agency
Industrial Environmental
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S7-84-024cj Sept. 1984
Project Summary
Evaluation of Low Emission
Coal Burner Technology on
Industrial Boilers: Third Annual
Report (1981)
B.A. Folsom, A.R. Abele, F.B. Jones, and J.L Reese
This report summarizes the third
year's effort under EPA Contract 68-
02-3127. The objective of the program
is to conduct a field evaluation of the
distributed mixing burner (DMB) on an
industrial size boiler. The DMB concept
provides for controlled mixing of coal
with combustion air to minimize NO*
emissions, while maintaining an overall
oxidizing environment in the furnace to
minimize slagging and corrosion. Major
accomplishments in 1981 included
completion of baseline host boiler tests,
completion of prototype DMB tests in a
burner test facility, and installation of
the DMBs in the host boiler.
This Project Summary was developed
by EPA's Industrial Environmental
Research Laboratory, Research Triangle
Park, NC, to announce key findings of
the research project that is fully
documented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
For the last several years. Energy and
Environmental Research Corporation has
been working with the EPA to develop a
low N0« pulverized coal burner. This
distributed mixing burner (DMB) controls
the mixing of coal with combustion air to
minimize NO,emissions, while maintain-
ing an overall oxidizing environment in
the furnace to minimize slagging, fouling,
and corrosion. DMBs have been tested at
firing rates up to about 100 x 106 Btu/hr*
"Readers more familiar with the metric system may
use the factors listed at the back of this Summary to
convert the nonmetric units used here.
in single- and four-burner arrays in two
research furnaces. The tests covered
wide ranges of burner adjustments and
operating conditions. When coal was
fired in the research furnaces under
optimum conditions, NO, levels less
than 0.15 lb/106 Btu were obtained.
However, the DMB performance has not
been evaluated in a commercially operated
steam generator. The objective of this
program is to evaluate the DMB concept
on two commercially operated industrial-
size boilers. The goal is to attain NO*
emission levels less than 0.2 lb/106 Btu
for new boilers, without adverse effects
on boiler operability and durability,
thermal efficiency, and the emission of
other pollutants. The field evaluation
involves: 1) translation of development
burner test data into a practical prototype
DMB, 2) verification of prototype burner
performance through testing in a research
furnace, 3) construction and installation
of these burners in the field boiler and
evaluation of their performance under
typical operating conditions, 4) documen-
tation of the results, and 5) input to the
parallel utility field evaluation (EPA
Contract 68-02-3130). The program is
being conducted in nine tasks. Table 1
lists the tasks and progress achieved.
In Task 1 all of the basic elements of the
program were planned, including boiler
selection, burner design, and establish-
ment of a measurements plan. The host
site boiler was selected, and negotiations
with the operators completed so that a
firm schedule for the remaining aspects
of the study could be established.
The final burner design was established
-------
Table 1. Program Status Summary
Task
Program
Field
Evaluation
Second
Prototype
Burner
Evaluation
Task 1 • Program Definition
Host Boiler Selection
Burner Engineering Design
Analytical Measurements Plan
Task 2 - Prototype Construction and
Testing
Prototype Burner Tests
Host Burner Tests
Task 3 - Boiler Baseline Evaluation
Task 4 - Burner Installation
Task 5 - Performance Evaluation
Task 6 - Industry Coordination
Task 7 - Restoration
Task 8 - Data Analysis
Task 9 - Guideline Manual
Boiler inventory
evaluated
Design criteria
identified
Measurements protocol
completed
Two panel meetings
were held
Selected
Prototype DMB
designed
Sampling system
constructed and
installed
Completed
Completed
Completed
Completed
Scheduled
for 1982
April 1984
In progress
September 1984
Selected
Scheduled
for 1982
when the boiler was selected. Prototype
burners (including all controls) were then
constructed, installed in EPA's large
watertube simulator (LWS) furnace, and
evaluated using several coals as part of
Task 2. In addition, the commercial
burners used in the host site boiler were
also evaluated in the LWS so that a one-
to-one comparison of operating charac-
teristics could be determined, and
potential problems identified.
The Task 3 boiler baseline evaluations
of the host unit establish normal operating
characteristics and the potential for
reducing NO. emissions by utilizing
various combustion modification tech-
niques associated wth operating point
changes. After the baseline characteri-
zation, the low NO. coal burners and all
support systems are installed on the host
boiler in Task 4. The burner and burner
systems then undergo checkout testing to
ensure their ability to perform similarly to
the original burners.
After Task 4, the low emission burner
system is ready for extensive evaluation
in Task 5. The retrofit boiler is operated
over a sufficient range of operating
conditions consistent with the operational
steam requirements to define the multi-
burner optimization of emissions so that
the operating point can be established. A
long-term evaluation (18 months) is then
conducted with the boiler operating
under a normal duty cycle. After this task,
the boiler/burner system is inspected
and the condition of all systems docu-
mented. Task 7 involves the restoration of
the boilers.
The remaining Tasks 6 and 8 are
accomplished concurrent with all of the
other tasks. Lastly, the final report. Task
9, involves integrating the overall effort
into a concise summary illustrating the
application of the technology to a wide
variety of coal-fired industrial boilers.
Originally the program involved field
evaluation of DMBs on two industrial size
boilers. Work on the initial field evaluation
has been in progress for 3 years. The
boiler is Pearl Station, a 215,000 Ib/hr
unit owned and operated by Western
Illinois Power Corporation (WIPCO).
DMBs have been installed in the WIPCO
unit and testing began in 1982. Due to the
complexity of the burner installation at
WIPCO and the resultant high cost, only
one field installation will be completed.
Work on the second field evaluation will
proceed only through prototype burner
testing in the LWS.
The progress on each task listed in
Table 1 was achieved over the last 2
years. Major accomplishments in 1981
include:
• Completion of the prototype burner
tests for the WIPCO unit (Task 2).
• Completion of the baseline field test
of the WIPCO unit (Task 3).
• Installation of the DMBs at WIPCO
(Task 4).
Prototype Burner Tests
The DMB concept involves staging the
combustion process to minimize NOx
emissions while maintaining an overall
oxidizing atmosphere in the furnace to
avoid furnace slagging and corrosion.
NOx production from fuel nitrogen
compounds is minimized by driving a
majority of the compounds into the gas
phase under fuel-rich conditions and
providing a stoichiometry/temperature
history which maximizes the decay of the
evolved nitrogen compounds to N2.
Thermal NO, production is also minimized
by enthalpy loss from the fuel-rich zone,
which reduces peak temperatures.
Figure 1 shows the DMB concept
schematically. Staging is achieved by
arranging the components for three-zone
combustion. In the first zone, pulverized
coal (transported by the primary air)
combines with the inner secondary air to
-------
Tertiary Air
Inner
Secondary Air
X
Coal and .
Primary Air
Very Fuel Rich
Zone (Average
Stoichiometry 4O%)
Progressive Air Addition Zone
(Overall Stoichiometry 70%)
Final Air Addition Zone for Burnout
(Overall Stoichiometry 120%)
Figure 1. DMB concept.
form a very fuel-rich (30 to 50 percent
theoretical air) recirculation zone which
provides flame stability. The coal devola-
tilizes, and fuel nitrogen compounds are
released to the gas phase. Outer secon-
dary air is added in the second burner
zone, where Stoichiometry increases to
about 70 percent theoretical air. This is
the optimum range for reduction of bound
nitrogen compounds to N2. Air to complete
the combustion process is supplied
through tertiary ports outside the burner
throat. This allows substantial residence
time in the burner zone for decay of bound
nitrogen compounds to N2 and radiative
heat transfer to reduce peak temperatures.
The tertiary ports surrounding the burner
throat provide an overall oxidizing
atmosphere in the burner zone.
A prototype DMB was designed to meet
the requirements of the intital host boiler.
The design involved integrating DMB
design parameters (based on previous
tests), the characteristics of the host
boiler, and Foster Wheeler burner
components. Figure 2 shows the central
portion of the burner without the tertiary
air ports.
Prototype burner tests in the LWS were
initiated in December 1979. These tests
utilized Utah bituminous coal, which was
used as a baseline fuel in previous burner
Perforated Plate
Air Hoods
Inner
Register
Outer
Register
Coal Inlet
Cast Refractory
Exit
Figure 2.
Prototype DMB based on Foster Wheeler mechanical components (tertiary ports not
shown/.
-------
tests. Later testing used the host boiler
coal. The tests were directed toward
evaluating burner performance under
unstaged conditions (with the tertiary air
ports closed). Some testing was also
conducted under staged conditions.
However, testing was halted when the
LWS furnace walls (which had already
exceeded their design life) deteriorated.
Analyses of these data showed that the
operability, flame shape, smoke, and CO
emissions for the prototype DMB were
comparable to the Foster Wheeler
intervane boiler, as installed at the host
site; however, NOX emissions were much
lower (as expected).
The LWS was rebuilt with several
design changes to make burner perform-
ance in the LWS more representative of
burner performance in field units as well
as to facilitate testing. The original LWS
was cooled on all surfaces, resulting in a
thermal environment significantly cooler
than that typically found in field operating
boilers, such as WIPCO's host boiler. To
produce a thermal environment compar-
able to that found in the WIPCO furnace,
the new LWS was partially lined with
insulating refractory.
The prototype burner was retested in
the new LWS under both unstaged and
staged conditions. The NOX emissions
from these tests were nearly identical to
those from the old LWS. However, the CO
emissions were substantially lower and in
the range of CO emissions from the
baseline field test at WIPCO. These
results suggest that the NO* emissions
from the DMB are insensitive to furnace
thermal environment over the range
investigated. Thus, NOX emissions from
the DMBs operated in the field are
expectd to be in the same range as those
from the LWS if comparable operating
conditions can be achieved. The results of
these tests were discussed in the Second
Annual Report (1980).
During the third year (ending November
1981), the prototype burner tests in the
new LWS were continued, to identify
optimum operating conditions. These
tests showed that operation at the burner
design point resulted in flame instability.
As the combustion air was diverted from
the burner throat to the tertiary air ports,
the flame became unstable at a burner
zone stoichiometry of 85 percent theoret-
ical air while the design point was 70
percent theoretical air. (NOTE: Burner
zone stoichiometry, expressed as percent
of theoretical air requirements, is the
ratio of the air supplied through the
burner throat to the air required for
stoichiometric combustion of the fuel.)
Stability limits were observed with some
of the development DMBs, and perform-
ance was improved by adjusting nozzle and
exit geometry.
Based on the original program plan, the
next step would have been to modify the
prototype burner geometry, retest it in the
LWS, and thus iteratively search for
conditions that optimize performance.
However, this would have delayed the
field installation of the DMBs by about a
year (due to WIPCO's outage schedule).
The alternative was to incorporate a
proven burner configuration known to be
stable under staged operating conditions
and to confirm burner performance in the
LWS while preparing for the field
installation. Foster Wheeler's controlled
flow burner has been operated in Japan
with burner zone stoichiometries com-
parable to the DMB, but using overfire
(instead of tertiary) air ports. Thus it was
decided to incorporate the Foster Wheeler
geometry into the DMB. This modified
prototype DMB was tested in the LWS
under unstaged and staged conditions.
The unstaged tests verified that flame stabi-
lity and shape were satisfactory over the
WIPCO boiler operating range. Thus the
DMBs can be operated unstaged if a
problem develops with the tertiary air port
system. The staged tests covered a range
of operating conditions and burner set-
tings. Flame stability at the burner design
point was satisfactory, and NOX emissions
were comparable to the original prototype
DMB tests. After the LWS tests, the
modified prototype DMB was tested in
another research furnace, the medium
tunnel (MT), to evaluate the effects of
furnace design on burner performance.
NO, and CO emissions measured in the
LWS and MT with an Indiana coal similar
to that fired at WIPCO are compared in
Figure 3. In the MT, NOx emissions are
higher and CO emissions are lower than
in the LWS. The differences between
Prototype 2 performance in the LWS and
MT may be due to thermal environment
and furnace confinement. The effects of
thermal environment on NOX emissions
from Prototype 1 were evaluated by
testing in the old and new LWS and were
reported in the Second Annual Report
(1980). The geometries for these furnaces
are almost identical: the primary differ-
ence is thermal insulation in the new LWS
which reduced the cooled surface area by
a factor of about two. NOX emissions from
Prototype 1 in the old and new LWS were
comparable. This indicates that NOX
emissions were unaffected by thermal
environment over the range investigated.
Of course, as furnace cooling is reduced
further, NOX emissions would be expected
to increase due to thermal NOxformation.
The smaller size of the MT narrowed
and elongated the flame, perhaps altering
the mixing of the tertiary air. Since the
basis of the low NOX emissions of the
DMB is delayed mixing of the tertiary air,
this may have affected NOX emissions.
One key objective of the prototype
burner tests was to verify that all aspects
of the burner performance meet the host
boiler requirements. Table 2 compares
the requirements of the WIPCO unit with
the performance of Prototype 2 in the
LWS. The LWS furnace geometry is
similar in shape to the WIPCO furnace.
The flame length in the LWS was 19 ft
which is shorter than the WIPCO furnace
depth, 20.6 ft. Thus, rear wall flame
impingement should not be a problem at
WIPCO. The flame was stable over the
WIPCO load and excess air ranges, and
flame stability was not affected by small
changes in burner settings or burner zone
stoichiometry. The flame scanning and
ignition system operation was compatible
with commercial standards.
Windbox-to-furnace pressure drop
with the secondary sleeves open full was
in the range of 1.5 to 2.0 in. HzO. This is
less than the 3.5 in. pressure drop
required by the original equipment
intervane burner. If required, the secon-
dary sleeves may be closed to increase
the pressure drop and to direct more air to
the tertiary ports.
CO emissions and carbon content of
the particulate were slightly greater than
the values measured during the WIPCO
baseline test. However, these parameters
are sensitive to furnace design, and the
differences are insignificant.
The prototype burner tests were
conducted using a 2 x 2 array of tertiary
air ports spaced symmetrically around
the burner throat. Due to structural
problems, a different array of tertiary air
ports will be used at WIPCO. The WIPCO
ports operate with the same air velocity
and distribute the air around each burner.
Thus the specific design details are not
expected to affect burner performance
significantly.
NOx emissions with the design fuel
(Indiana coal) were 0.22 lb/106 Btu at the
optimum full-load operating point. This is
very close to the program goal of 0.2
lb/106 Btu. The differences between the
prototype burner tests in the LWS and the
field operating DMBs at WIPCO are
expected to affect NOx emissions. These
differences include:
The precise effects of these differences
cannot be evaluated based on existing
data. Minimum NOX emissions for the .
DMBs operating at WIPCO are expected m
to be in the range of 0.2 to 0.3 lb/106 ^
-------
900
7*00
500
[5001-
L
,4OO'
i3OO
200
700
0
T.A. = Theoretical Air
300
250
ISO
100
SO
i i i
Fuel = Indiana Coal
O MTSRt = 120% T.A.
15.4 MW
(52.4 x 10s Btu/hr)
• LWSSfa= 126% T.A.
20.2 MW
*<•$*
GD
50 60 70 80 90 1OO SO 60 70 80 90 100
Burner Zone Stoichlometry. % T.A.
Figure 3. Comparison of Prototype 2 performance in the L WS and MT with Indiana coal.
Table 2. Prototype 2 Performance Summary
Parameter
Requirement
Btu/hr, if the operating conditions tested
in the research furnaces can be achieved.
Boiler Baseline Evaluation
The objective of the Task 3 boiler
baseline evaluation is to evaluate the
performance of the host boiler with the
original equipment burners. The data are
used to establish the operating require-
ments for the DMBs and to determine the
baseline boiler performance and emis-
sions for assessing the net change due to
retrofitting the DMBs.
The baseline tests were conducted in
four series: burner modification tests, 30-
day baseline tests, effluent stream
analysis, and a thermal efficiency test.
The burner modification tests involved
monitoring burner and boiler performance
and emissions as the operating conditions
and emissions were adjusted over the
maximum possible ranges. As part of
these tests, operating limits were estab-
lished. After the burner modification
tests, boiler performance and emissions
were monitored for 30 days while the
operators met the normal duty cycle.
Results of the burner modification and
30-day baseline tests are discussed in
this report. The effluent stream analysis
and thermal efficiency test involved a
comprehensive assessment of burner/
Demonstrated Performance
Flame Shape
Flame Stability
Ignition
Flame Scanning
Pressure Drop
Efficiency
Tertiary Air
Ports
Control System
/I/O,
Compatible with host furnace
Stable over host load range;
insensitive to burner settings
Compatible with commercial system
Compatible with commercial system
Less than/equal to host burner
Equal to/better than host burner
Locations compatible with host furnace
Compatible with commercial standards
Program goal: 0.2 lb/106 Btu
Flame length: 19 ft
Minimum load less than 50 percent MCR*
Stability insensitive
Confirmed
Confirmed
1.5 to 2.5 in. H£>
CO = 70 ppm; carbon in ash =4.4percent
Ports redesigned for
field evaluation
0.22 lb/10e Btu at design point
Sensitive to excess air and burner zone
stoichiometry
Insensitive to load
'Maximum Continuous Rating.
Parameter
Number of Burners
Number of Tertiary Air Ports
Fuel
Furnace Depth., ft
Thermal Environment, Q/A,
Btu/hr-ft1
Prototype
Tests in
LWS
1
4
Indiana
22
^lOO.OOO
WIPCO DMB
Field Evaluation
4
12
Varies
20.6
"130.OOO
-------
boiler performance and emissions,
including an EPA Level 1 environmental
assessment at the nominal full-load
operating point. Results of these tests will
be presented in a later report.
Measurements conducted during the
burner modification and 30-day baseline
tests followed the measurements proto-
col, discussed in the Second Annual
Report (1980). Detailed results are
discussed in the full Third Annual Report
(1981) and are summarized below. Table
3 summarizes the emissions at nominal
conditions, during both the 30-day
baseline test and the effluent stream
analysis. During the 30-day baseline test,
boiler operating conditions were selected
by the operators. During the effluent
stream analysis, the boiler was operated
at nominal operating conditions. Boiler
operating conditions were similar during
each of the three test series. The average
load measured during the 30-day test
was 18.5 MW, showing that the unit
operates primarily at or near full-load.
The excess air was slightly higher during
the 30-day baseline test and the effluent
stream analysis, but this higher excess
air did not significantly affect boiler
emissions. Combustion efficiency, mea-
sured by carbon utilization, was nearly
constant for all three test series. NOX and
CO emissions during the 30-day baseline
test and effluent stream analysis were
very close to the baseline emissions
measured during the burner modification
tests. SO a SO 3, and paniculate emissions
varied due to changes in the sulfur and
ash content of the coal. Hydrocarbon,
HCN, and NH3 emissions were all very
low. The low CO and hydrocarbon
concentrations are comparable to those
observed on other Foster Wheeler boilers
of similar design. The baseline NOX
emissions are about 15 percent higher
than had been previously estimated by
Foster Wheeler for this type of boiler.
Operating conditions and burner
adjustments evaluated during the burner
modification test included load (firing
rate), excess air, core air valve settings
and register positions. The effects of load
and excess air on NOX emissions are
shown in Figures 4 and 5. CO emissions
were essentially constant at about 40
ppm (@ 0% Oa dry) over the ranges
evaluated. Burner adjustments had no
significanteffect on NOx or CO emissions.
Results of the 30-day test are summa-
rized in Figure 6. The boiler operated at
nearly full-load during this period, and
the measured performance was compar-
able to that observed during the burner
modification tests.
DMB Field Evaluation
The WIPCO host boiler has been
retrofitted with DMBs. The burner,
tertiary air ports, and control system were
installed in the spring and summer of
1981. For the remainder of the third year
(ending November 1981), the burners
Table 3. Nominal Boiler Operating Conditions and Emissions
Test Series and Dates
Burner
Modification
Tests
(6/30/80 to
7/12/80)
30-Day
Baseline Test
Average
(7/15/80 to
8/17/80)
Effluent
Stream
Analysis
(3/22/81 to
3/27/81)
Boiler Operating
Conditions:
Load. MWe 20.3
Excess Air, % 18.9
Carbon Utilization, % 99.54
Emissions:
/VOx @ O% Oz, ppm 826
CO@0%Ot,ppm 41
SOz @ 0% Oz, ppm 3364
S03 @ 0% On, ppm 22
CO2 @O%Oi,% 18.9
O2@0%02,% 3.4
Hydrocarbons @ O% Oz, ppm 1
Total Paniculate @ O% Oz 7.98
gr/scf
18.5
20.5
99.36
847
37
3299
25
18.5
3.6
1
5.93
19.7
23.2
99.67
807
32
4289
35
18.1
4.0
4
9.83
Paniculate/ ash in coal
HCN @ O% Oa ppm
NH3 @ 0% Oz. ppm
0.965
NM*
NM
0.828
NM
NM
0.812
*NM = Not measured.
"J ppm is detection limit.
were operated with the tertiary air ports
closed (only leakage air passing through).
Performance optimization tests under
staged conditions are scheduled to begin
during the fourth year.
The DMBs installed at WIPCO are
based on the design of Prototype 2 which
was tested in the LWS. The registers, coal
nozzle, and burner exit are identical
except that the materials of construction,
fasteners, etc., for the WIPCO burners
have been upgraded to Foster Wheeler
commercial standards for field operating
equipment. The tertiary air port array at
WIPCO is designed to match the tertiary
air velocity used in the prototype test;
however, due to the multiburner config-
uration and structural constraints, the
number and location of ports are con-
siderably different.
The desired tertiary air port arrangement,
which included nine ports, interfered
with buckstays, windbox trusses, and
pulverizer air supply ducts. Also, it
critically weakened the hopper support
tubes. After considerable analysis and
discussion, the compromise port arrange-
ment shown in Figure 7 was selected.
This arrangement distributes the tertiary
' air around and between the burners
while minimizing structural problems.
The ports above the burners are the
maximum sizS that will clear the buckstay.
The port in the center is reduced in
diameter to allow clearance for its control
mechanism between the burner registers.
The ports along the sides have been
moved to allow free flow into the
pulverizer ducts. The bottom of the
windbox has been lowered to provide a
plenum for installation of the lower ports.
Conclusions and Future Efforts
Conclusions
Based on the work conducted during
this third year of the program, the
following conclusions have been reached:
1. Prototype Burner Tests
The prototype burner tests in the LWS
demonstrated that the DMB meets all
requirements of the host boiler. NO*
emissions were 0.22 lb/106 Btu. This
is close to the program goal of 0.2
lb/106 Btu.
2. Boiler Baseline Evaluation
The host boiler performance was
found to be typical of pre-"NSPS
pulverized-coal-fired boilers. NO*
emissions during a 30-day test
averaged 0.95 lb/106 Btu. No signifi-
cant NOx reduction could be achieved
by low excess air firing or burner
adjustments.
-------
BOO
850
•6
O
ao°
7BO
i
700
650
O
D
NO, Load Correlation
N0, = 2.30 Load ^ 595.1
Note: All data corrected to 18% excess air.
Minimum load test fa) not included in
correlation.
I I I \ I
70
75
80 85
Load. % of full
90
95
100
105
Figure 4. Effect of load on NO*.
950 -
9OO
I
O
8OO
i
750
700
NO, Excess Air
Correlation
NO, = 9.30 Excess Air + 657.7
O
Note: All data corrected to 1OO% load.
Test at minimum load fl3) not
included in correlation.
I
W
15
20
Excess Air.'
25
30
35
40
Figure. S. Effect of excess air on NO*
3. DMB Field Evaluation
The DMBs were installed in the
host boiler in the spring of 1981. To
accommodate the structural constraints
imposed by the existing windbox/
furnace, it was necessary to modify
the tertiary air port array from the
configuration tested in the LWS. The
burners are now operating satisfac-
torily with the tertiary air ports closed.
Future Efforts
Future efforts will focus on two
principal objectives: field evaluation of
the DMBs installed in the WIPCO host
boiler; and development and research
furnace tests of a prototype DMB based
on the DMB design criteria.
The DMBs have been installed in the
WIPCO furnace and are now operating
unstaged. At a future outage, tubewall
thickness will be measured throughout
the furnace to establish a baseline for
corrosion rate measurements. Following
the outage, the DMBs will be tested over a
range of operating conditions and burner
settings to establish an optimum balance
of flame stability, efficiency, and emis-
sions. The initial operating point will be
the optimum settings established during
the LWS tests of Prototype 2. Due to the
difference between the LWS and WIPCO
furnaces, it is expected that some
adjustments of burner settings may be
required. Burner performance, boiler
performance, and emissions will be
measured over the full range of operating
parameters and burner settings as
specified in the measurements protocol.
Once the optimum operating point is
established the boiler operators will be
trained to operate the unit. After the
training program, the operators will run
the unit over the normal duty cycle while
burner performance, boiler performance,
and emissions are monitored. At the
conclusion of the testing period, the unit
will be restored as required by the boiler
owner. Also, furnace tubewall thickness
will be measured to evaluate the rate of
corrosion.
During the LWS tests of Prototype 1,
the flame stability at the burner design
point was unacceptable. Due to a time
constraint on the burner installation at
WIPCO, a decision was made to alter the
burner exit geometry to that of Foster
Wheeler's controlled flow burner, since
burners with this geometry have adequate
flame stability under reducing conditions
with overfire air ports. However, this
geometry is not necessarily optimum for
DMB operation. Consequently, a second
series of prototype burner tests will be
conducted to optimize performance
under DMB conditions. This will involve
making iterative modifications to the
nozzle and throat geometry, and evaluat-
ing flame stability, efficiency, and
emissions in the LWS.
Conversion Factors
Readers more familiar with metric
units may use the following factors to
convert nonmetric units used in this
Summary to their metric equivalents:
Nonmetric
Times Equals Metric
Btu/hr
Btu/hr-ft2
ft
gr/scf
in.
Ib/IO* Btu
Ib/hr
2.93
11.35
0.305
2.29
2.54
430
0.455
Wt
kJ/hr-m2
m
ff/m3
cm
ng/J
kg/hr
-------
so
CO @ 0% 0» 60
ppm
4O\
20
1000/0
/V0,@0%0» 9OO,
80O
70O
5/6OO,
Ot.%
Boiler Load.
MW.
4
3
25/2
2O
IB
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Std Dev =7.1 ppm
- 36.75 ppm
Std Dev = 39.4 ppm
Avg = 849 ppm
Std Dev = 0.3 ppm
= 3.6%
Std Dev = 0.8 ppm
Avg= 18.5 MW
IB 17 1921 232530311 35 7 9 11 13 15 17
July August
Note: Boiler shut down July 25-30, 1980. fof unscheduled outage unrelated
to 30-day test.
Figure 6. 30-day baseline test results.
-------
4 Pans,
8.0 in. Die
Lowered Windbox
Bottom
Figure 7. Final compromise port arrangement.
B. Folsom, A. Abele, F. Jones, and J, Reese are with Energy and Environmental
Research Corp., Irvine, CA 92714.
G. Blair Martin is the EPA Project Officer (see below).
The complete report, entitled "Evaluation of Low Emission Coal Burner
Technology on Industrial Boilers: Third Annual Report (1981)," (Order No. PB
84-220 284; Cost: $13.00, 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:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
*USGPO: 1984-759-102-10678
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