United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S7-83-061 Jan. 1984
Project Summary
Evaluation and Demonstration
of Low NOX Burner Systems for
TEOR Steam Generators—
Test Report: Preliminary
Evaluation of Commercial
Prototype Burner
G. England, Y. Kwan, and R. Payne
The report summarized here describes
the preliminary testing of a 16 MW low-
NOX burner for thermally enhanced, oil
recovery (TEOR) steam generators.
These "steamers" are often required to
burn low-grade fuels with minimum
environmental impact.
The 16 MW commercial prototype
burner described in this report was
developed from scaling criteria gener-
ated in previous bench- and pilot-scale
experiments supported by EPA. NO«
emissions can be reduced by staging
the combustion process. The design of
this burner is based on optimizing
conditions of stoichiometry, tempera-
ture, residence time, and mixing so that
NOx emissions are minimized. The cur-
rent design utilizes a separate, regener-
atively cooled prechamber. Fuel and a
portion of the combustion air enter the
prechamber and burn under optimum
fuel-rich conditions. Secondary air is
injected at the prechamber exit into the
furnace where combustion is com-
pleted.
The tests were conducted in an experi-
mental test furnace which closely simu-
lates the thermal environment of a
watertube boiler. Firing a 0.74 percent
nitrogen residual fuel oil with the opti-
mum burner configuration produced 49
ppm of NO,, 35 ppm of CO (corrected
to 3 percent oxygen), and a Bacharach
smoke number of 2 to 4. Flame condi-
tions within the furnace were favorable,
with no impingement on any of the test
furnace surfaces. Although the geom-
etry of the test furnace (L/D = 1.4) is
different from TEOR steamers (L/D = 4)
the flame characteristics appeared to be
well suited for the intended applications.
This document summarizes the results
of tests to determine the effects of first-
stage parameters (swirl, throat geom-
etry, stoichiometry) and second stage
parameters (air injection geometry, ex-
cess air) on emissions and flame charac-
teristics. Turndown was also investi-
gated. Thermomechanical performance
of the burner hardware and control
system performance are also discussed.
The results of the preliminary evalua-
tion demonstrated the ability of the
burner to produce very low NOX levels
on a high-nitrogen heavy residual oil,
with low smoke and CO emissions, and
with a flame which appears to be
compatible with field steam generators.
The burner hardware has performed
without serious mishap for the short
duration of these tests. Final optimiza-
tion and detailed evaluation of the
burner hardware and control system
will take place during the field evalua-
tion.
This Project Summary was developed
by EPA's Industrial Environmental Re-
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search 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 in-
formation at back).
Introduction
Enhanced oil recovery processes are
applied to oil field production in order to
extract heavy, viscous crude oil and tar
sands which cannot otherwise be pro-
duced. A significant fraction of total U.S.
oil reserves require application of en-
hanced oil recovery in order to be realized.
Thermally enhanced oil recovery
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Controls
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Figure 1. TEOR steamer low-NO* burner, regeneratively cooled concept.
100
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1
50
1 1 1 1 1
. 1 5.7 MW thermal
3.0% Excess O2
. A^o diffuser, primary swirl No. =0.9 -
12 axial/0 radial secondary ports
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100
o
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i
1
50
15.5MW
- 2.9% Excess O2
16 Axial/0 Radial Secondary Ports
O With Diffuser fS = 0.3)
_ D Without Diffusion (S = 0.9)
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1
m
•s
150 -
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o 100
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o
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0.50
0.60
0.70 0.50
SRi
0.60
0.70
Figure 3. Effect of primary configuration on emissions.
Medium Tunnel
6m —
16 MW
2.0 - 3.0% O2
12 Axial Ports
No Radial Ports
4.3m
Steam Generator
Radiant Section
2.7m
16 Axial Ports
No Radial Ports
| 1
Figure 4.
Comparison of flame length observed in the MTforthe 12and16axialports(J6MW,
2.0-3.0% Ot).
sions increased. The high smoke and CO
emissions were associated with the long
flame produced with no radial air injection
and with the primary diffuser in place.
Variation of the number of axial ports
(hence velocity) without radial air injec-
tion showed that moderate variation of
flame length is possible without strongly
affecting emissions. Figure 4 compares
flame shape for 12 and 16 axial ports,
corresponding to secondary air injection
velocities of 50 and 35 m/s, respectively,
at the minimum NOX condition. A de-
crease in flame length of approximately 1
meter was observed when the number of
axial ports was decreased from 16 to 12
(thereby increasing velocity), while mini-
mum NOX emissions decreased slightly
from 54 ppm to 48 ppm, corrected to 3
percent O2. Based on these results, final
optimization of second-stage mixing with
respect to flame shape should be possible
in the field without significantly compro-
mising emissions performance.
Hardware Performance
Excess oxygen in the second stage was
also varied under one test condition:
results showed that NOX emissions were
relatively insensitive to Qz level.
Hardware performance was generally
excellent, except for minor shakedown
problems. Inspection of the refractory
lining after the test revealed no signs of
significant damage. A portion of the lining
appeared to have shifted slightly due to
thermal expansion; however, this was
not considered serious. Overall appear-
ance of the lining was excellent.
Thermal performance of the first-stage
chamber was well within the calculated
design performance. Temperature of the
stainless steel shells was well below the
design point maximum at normal full-
load conditions. Transient thermal perform-
ance of the lining during a long-term
sudden shutdown was not determined.
Control system operation during light-
off and shutdown sequences was satis-
factory. Full control system characteriza-
tion was not achieved; however, a brief
test of the programmable controller trim
loop showed that SRi and excess O2could
be closely maintained over a narrow
range of load near full load. Final setup
and optimization will take place in the
field.
Conclusions
The results of the preliminary evalua-
tion are encouraging and suggest that the
program emission goals will be easily
achieved in the field. Characteristics of
the flame produced by the commercial
prototype burner in the medium tunnel
furnace are very good and should easily
fit within the confines of the field steam
generator radiant section.
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G. England, Y. Kwan, and R. Payne are with Energy and Environmental Research
Corporation. Irvine, CA 92714-4190.
W. S. Lanier is the EPA Project Officer (see below).
The complete report, entitled "Evaluation and Demonstration of Low /VOX Burner
Systems for TEOR Steam Generators—Test Report: Preliminary Evaluation of
Commercial Prototype Burner," (Order No. PB 84-128 727; Cost: $10.00,
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
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use S30O
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U.S. GOVERNMENT PRINTING OFFICE: 1984-759-102/836
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