o
EPA PROJECT REPORT NO. 75-LS6-2
I SSI
MINNKOTA POWER COOP, INC.
Milton R. Young Station
Center, North Dakota
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Emission Measurement Branch
Research Triangle Park. North Carolina
-------
REPORT NO. Y-8479-6 PAGE
TEST REPORT
of
NITROGEN OXIDE EMISSIONS
at
THE MINNKOTA POWER COOPERATIVE
MILTON R. YOUNG STATION
CENTER, NORTH DAKOTA
Prepared For
i
THE ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK
NORTH CAROLINA 27711
UNDER CONTRACT NO. 68-02-1401 TASK 6
REPORT NO. 75-LS6-2
Submitted By
YORK RESEARCH CORPORATION
ONE RESEARCH DRIVE
STAMFORD, CONNECTICUT 06906
REPORT NO. Y-8479-6
May 16, 1975
CORPORATION SB STAMFORD. CONNECTICUT
-------
REPORT NO. Y-8479-6 PAGE
TABLE OF CONTENTS
SECTION TITLE PAGE
I. INTRODUCTION ]_
II. SUMMARY AND DISCUSSION OF RESULTS 2
Table 1A - Summary of Average Test 4
Results
Table IB - Comparison Duct 2 to Duct 1 6
Data
Table 1C - Average Excess Air at 7
Sampling Site
Table II - Test Results 8
Table III- Volumetric Flow 11
Table IV - Plant Operating Data 13-
Table V - Coal Analysis Results 14
III. PROCESS DESCRIPTION AND OPERATION 15
IV. LOCATION OF SAMPLING POINTS 16
V. SAMPLING AND ANALYTICAL PROCEDURE 26
RESEARCH CORPORATION feSI STAMFORD, CONNECTICUT
-------
REPORT NO. Y-8479-6
PAGE.
NUMBER
1.
2
3
4
5
6
7
8
LIST OF FIGURES
TITLE
Milton R. Young Station
Schematic of Ducts 1 and 2
including Port Locations
Cross Section of Duct
NOX Sampling Train
Chemiluminescent NO-NO Gas
Analyzer and Conditioning
Flue Gas Collection by Leveling
Bottle
Preliminary Moisture Determination
Train
Pitot Tube-Manometer Assembly and
Thermocouple-Pyrometer
PAGE
18
19
20
21
22
23
24
25
STAMFORD, CONNECTICUT
-------
REPORT NO. Y-8479-6 PAGE
I. INTRODUCTION
York Research Corporation, an independent consultant in Environ-
mental Engineering, was retained by the United States Environ-
mental Protection Agency, under Contract No. 68-02-1401, Task 6
to conduct a series of tests at the Minnkota Power Cooperative,
Milton R. Young Station, Center, North Dakota.
These tests were performed on a Babcock and Wilcox designed
cyclone burner boiler burning lignite and equipped with a
cyclone dust collector. A York Research team consisting of a
Project Director and four test engineers conducted the series.
The primary purpose of the test program was to determine nitrogen
oxide emission levels. Analysis of the test results will then
assist the Environmental Protection Agency in establishing NO,
standards of performance for new lignite fired boilers.
x
Sampling of the exhaust gases was conducted from sampling ports
located on two ducts to determine nitrogen oxide concentrations,
molecular weight, moisture content, velocity and flow. Con-
currently, samples of the lignite were collected for examination.
Pertinent process data was supplied by A.D. Little, Inc., under
a separate contract, and was used to calculate some of the
emission rates presented in this report.
N0-x emissions were also recorded with a Thermo Electron Corpora-
tion "Chemiluminescent NOX Analyzer" to check for variations in
the NOX emissions which would not be detected by the EPA Method
7 sampling program. This included monitoring under varied
excess air situations to confirm that NO emissions were depen-
dent on operating conditions.
CORPORATION fsmsj STAMFORD, CONNECTICUT
-------
REPORT NO. Y-8479-6
PAGE. 2
II. SUMMARY AND DISCUSSION OF RESULTS
STAMFORD, CONNECTICUT
-------
REPORT NO. Y-8479-6 PAGE 3
11• DISCUSSION OF RESULTS
In determination of the NO emissions the following results
were obtained:
The NOX emissions (gin per 1C)6 joules) could be reduced by an
average of 16.7% with a reduction in excess air (at the test
sampling point) from 20.85% to 18.7% or a reduction in excess
air at the furnace outlet from 21.5% to 17%. The reduction in
excess air resulted in a 1.0% reduction in gas flow.
By increasing the excess air to 22.45% (3% increase in gas
volume) the N0x emissions were increased by 3.8%. Although
these variations in NOX were obtained by changing boiler
operating conditions, no long runs were made under these
conditions. Therefore, York Research cannot ascertain if the
boiler can operate under these conditions permanently and
maintain the same level of reduction.
The TECO NOX analyzer averaged 15-30 ppm higher than the
EPA-7 test methods at this plant. As the TECO's purpose was
to indicate significant trends in the NO concentrations, its
results should not be considered equivalent to the EPA-7
data.
A comparison of Duct 2 data with Duct 1 data has been shown
in Table IB. Contrasted at the same time period, it indicates
that NO emissions in the two ducts were very close to one
another, confirming the suspected similarity between the two
gas streams.
CORPORATION ™&3 STAMFORD, CONNECTICUT
-------
TABLE 1A
SUMMARY OF AVERAGE TEST RESULTS
Concentration Emission Rates^
(ppm @ 3% (Gm/106
Flow (ppm, dry) 02, dry) (Lb/Hr) (Lb/MMBTU) noules) Lb/ Gm/
Date Phase/Duct (SCFMD) EPA-7 TECO EPA-7 TECO EPA-7 TECO EPA-7 TECO EPA-7 TECO MMBTU3 I06ioulei
10/5 Prelim/1 NM 427 453
Prelim/2 NM
Total NM 427 453 NM NM . NM NM NM NM • NM NM
10/7 Baseline/1 306,346 532 581 555 609
Baseline/2 303,521
Total 609,867 532 581 555 609 2313 2546 .853 .930 .367 ^400 .782 .336
(13) (7)
10/8 AM Base-
line/1 330,343 560 581 587 608
AM Base-
line/2 314,682
Total 645,025 560 581 587 608 2575 2682 .990 1.03 .426 .443 .879 .378
(5) (3)
AM Low
Air/1 313,926 461 470 469 478
AM Low
Air/2 307,787
Total 621,713 461 470 469 478 2044 2083 .788 .803 .339 .345 .703 .302
(5) (5)
PM Base-
line/1 329,812 551 559 571 579
PM Base-
line/2 315,073
Total 644,885 551 559 571 579 2534 2570 .977 .991 .420 .426 .867 .373
(5) (5)
-------
TABLE 1A (Con't)
SUMMARY OF AVERAGE TEST RESULTS
Concentration Emission Rates^
(ppm i> 3% (Gm/106
Flow (ppm, dry) 0?, dry) (Lb/Hr) (Lb/MMBTU) joules) Lb/ Gm/
Date Phase/Duct (SCFMD) EPA-7 TECO J5PA-7 TECO EPA-7 TECO EPA-7 TECO EPA-7 TECO MMBTU3
^ 10/9 Baseline/1 307,136 491 528 513 550
O Baseline/2 308,738
Total 615,874 491 528 513 550 2156 2319 .809 .870 .348 .374 .756 .325
O (5) (4)
High Air/1 329,243 609 617 646 664
High Air/2 322,985
Total 652,228 609 617 646 664 2832 2869 1.05 1.06 .451 .456 .944 .406
(5) (5)
Baseline/1 316,547 635 622 658 644
^ Baseline/2 316,837
Total 633,384 635 622 658 644 2868 2809 1.06 . 1.04 .456 .447 .969 .417
(5) (5)
10/10 Baseline/1 309,868 534 536 . 552 554
Baseline/2 309,642
Total 619,510 534 536 552 554 2359 2368 .881 .884 .379 .380 .846 .364
(5) (5)
High Air/1 325,610 519 542 547 571
High Air/2 316,319
Total 641,929 519 542 547. 571 2375 2481 .889 .928 .382 .399 .829 .356
(5) (5)
Note 1: Number of samples used to determine averages are shown in parenthesis below the
"Lb/Hr" values.
O Note 2: These emission rates are based on volumetric flow rates and process data as shown
in Tables III and IV, respectively.
Note 3: These emission rates were determined using "F Factors" as described in Section V
of this report.
O
d
H
-------
<
D
?d
^
^
3
Tcj
>
33
D
s
rial
n
D
^
p~-i
TO
D
sd
>
^
D
2
•ft
3m
T!
P
**
1FORD, CONNECT]
14
O
C
>*
TABLE IB
COMPARISON DUCT 2 TO DUCT 1 DATA
Concentration Emission Rates
(Gm/106
Flow (ppm) (Lb/Hr) 2 (Lb/MMBTU) 2 -joules2)
Date Phase/Duct (SCFMD) EPA- 7 TECO EPA- 7 TECO EPA- 7 TECO EPA- 7 TECO
10/7 Baseline/1 304,868 609 700 1324 1521 .487 .560 .209 .241
(13) (7)
Baseline/2 300,941 640 70.0 1373 1502 .506 .553 .218 .238
(3) (1)
10/8 PM Baseline
/I 331,114 541 550 1278 1298 .470 .501 .202 .215
(5) (5)
PM Baseline
/2 314,584 520 545 1167 1222 .450 .471 .193 .203
' (3) (1)
10/9 High Air/1 325,935 627 620 1457 1441 .537 .534 .231 V230
(5) (5)
High Air/2 323,512 626 640 1444 1476 .536 .547 .230 .235
(4) (1)
10/10 High Air/1 323,614 501 540 1156 1246 .426 .466 .183 .200
(5) (5)
High Air/2 323,892 517 540 1194 1247 .447 .467 .192 .201
(3) (1)
Lb/
MMBTU 3 Gm/106 Cal3
.893 1.61
.943. 1.70
.846 1.53
.821 1.47
.991 1.78
.989 1.78
.801 1.45
.840 1.52
Note 1: Number of samples used to determine averages are shown in parenthesis below the
"Lb/Hr" values.
Note 2: These emission rates are based on volumetric flow rates and process data as shown
in Tables III and IV, respectively.
Note 3: These emission rates were determined using "F Factors" as described in Section V
of this report.
-------
<
D
a
*
?d
*1
ff)
5j
>
S)
^
3!
f}
D
s
°d
D
^H
#9
>
H
5
7»
<£<
fl
-I'M
°3>x
STAMFORD
CONNEC
P
O
G
*4
TABLE 1C
,
AVERAGE EXCESS
AIR AT SAMPLING SITE
MILTON YOUNG
Phase
Baseline
Baseline
Low Air
Baseline
Baseline
High Air
Baseline
Baseline
High Air
Time CO-> 0^
10/7
10/8
10/8
10/8
10/9
10/9
10/9
10/10
10/10
15.91
AM 16.0
AM 16.05
AM 16.05
AM 16.0
AM 16.3
PM 16.3
AM • 15.35
AM 15.8
^_
3.71
4.05
3.5
3.7
3.75
3.6
3.5
4.05
3.85
ORSAT DATA
CO
.07
.0
.1
.45
.1
.15
.35
.1
.15
80.31
79.95
80.35
79.8
80.15
79.95 •
79.85
80.5
80.2
EA*
21.0
23.7
19.4
19.8
21.2
20.0
18.7
23.2
21.7
Average Base-
line
Average Low
Air
Average High
Air
*Excess air
figures
%EA -
16.05
16.3 .
15.58
computed with the
100 x %0?
0.264 x %N2- %02
3.72
305
3.95
following
.145
.35
.125
equation:
80.09
79.85
80.35
20.85
18.7
22.45
-------
YORK RESEARCH CORPORATION STAMFORD, CONNECTXCUI
TABLE II
TEST RESULTS
Concentration
Date & Flow*
Phase Time (SCFMD)
10/7 0830 618,732
Base- 0900 618,732
line 0930 621,338
1000 621,338
1030 598,929
1100 598,929
1130 620,323
1200 620,323
1230 599,961
1300 599,961
1330 612,970
1400 612,970
1430 596,811
10/8 0800 639,372
Base- 0830 639,372
line 0900 650,860
0930 650,860
1000 650,860
10/8 1030 624,101
Low 1100 624,101
Air 1130 619,324
1200 619,324
1230 619,324
(ppm.
EPA- 7
489
500
412
385
421
546
479
594
625
578
628
666
597
564
566
562
530
577
447
408
484
482
483
dry)
TECO
480
480
365
700
700
680
665
600
600
545
460
430
480
480
500
(ppm d> 3%
09, dry)
EPA- 7
524
536
426
401 .
431
572
496
618
651
609
661
681
611
597
566
599.
555
619
460
412
498
490
483
TECO
515
515
378
729
729
716
680
600
639
584
473
435
494
488
500
Emis
Lb/Hr **.
EPA- 7 TECO
2157 2118
2206 2118
1825 1617
1706
1798
2332
2119
2627 3096
2674 2994
2473
2745 2972
2911 2906
2540
2571
2580 2735
2608 2784
2460
2678 2529
1989 2047
1916 1913
2137 2120
2128 2120
2133 2207
sion Rates
Lb/
MMBTU**
EPA- 7 TECO
.794 .780
.812 .780
.672 .595
.628
.662
.859
.780
.967 1.13
.984 1.10
.910
1.01 1.09
1.07 1.07
.935
.989
.992 1.05
1.00 1.07
.946
1.03 .973
.767 .789
.700 .738
.824 .817
.821 .817
.823 .851
Gm/**
106ioules
EPA- 7
.341
.349
.289
.270
.285
.369
.335
.416
.423
.391
.434
.460
.402
.425
.427 .
.430 .
.407
.443 .
.330 .
.301 .
.354 .
.353 .
.354 .
TECO
.335
.335
.256
.486
.473
.469
.460
451
460
418
339
317
351
351
366
Lb/***
MMBTU
.750
.767
.610
.573 .
.615
.819
,709
.884
.930
.872
.948
.976
.875
.771
.730
.773
.717
.798
.594
.533
.643
.630
.625
Gm/***
106 loules
.323
.330
.262
.246
.264
.352
.305
.380
.400
.375
.408
.420
.376
.332
.314
.332
.308
.343
.255
.229
.276
.271
.269
-------
YORK RESEARCH CORPORATION STAMFORD, CONNECTICUT:
TABLE
II
TEST RESULTS
Concentration
Date &
Phase
10/8
Base-
line
10/9
Base-
line
10/9
High
Air
10/9
Base-
line
Flow*
Time (SCFMD)
1300 645,698
1330 645,698
1400 644,072
1430 644,072
1500 644,072
0800 614,998
0830 614,998
0900 616,750
0930 616,750
1000 616,750
1030 655,008
1100 655,008
1130 649,447
1200 649,447
1230 649,447
1300 631,893
1330 631,893
1400 634,874
1430 634,874
1500 634,874
(ppm,
EPA- 7
524
558
542
560
571
473
503
503
472
506
581
586
655
598
624
621
615
631
684
626
dry)
TECO
540
560
565
560
570
520
520
520
550
605
600
620
620
640
620
610
630
640
610
(ppm d> 3%
0?, dry)
EPA- 7
552
578
545
580
598
495
527
521
491
530
612
621
702
641
653
650
629
657
704
648
TECO
569
580
568
580
597
544
538
541
576
637
635
665
665
718
649
624
656
658
631
Lb/Hr
EPA- 7
2412
2569
2489
2572
2622
2074
2206
2212
2076
2225
2713
2737
3033
2769
2889
2798
2771
2856
3096
2834
Emission Rates
Lb/ Gm/**
** MMBTU** 106-joules
TECO EPA- 7 TECO EPA- 7
2486 .930 .959 .400
2578 .991 .994 .426
2595 .960 1.00 .413
2572 .992 .992 .427
2618 1.01 1.01 .434
.779 .335
2280 .828 .856 .356
2287 .830 .858 .357
2287 .779 .858 .335
2419 .835 .908 .359
2825 1.01 1.05 .434
2802 1.02 1.04 .439
2870 1.13 1.06 .486
2870 1.03 1.06 .443
2964 1.07 1.10 .460
2793 1.03 1.03 .443
2748 1.02 1.01 .439
2852 1.05 1.05 .451
2897 1.14 1.07 .490
2761 1.05 1.02 .451
TECO
.412
.427
.430
.427
.434
.368
.369
.369
.390
.451
.447
.456
.456
.473
.443
.434
.451
.460
.439
Lb/***Gm/***
MMBTU 106 ioules
.713
.746
.677
.749
.823
.629
.669
.661
.623
.674
.778
.720
.893
.815
.790
.826
.800
.834
.895
.824
,307
.321
.291
.322
.354
.270
.288
.284
.268
.296
.334
.340
.384
.350
.340
.355
.344
.359
.385
.354
-------
M
z
a
%
o
o
»
*3
o
o
§
o
o
z
z
m
O
a
o
c
H
TABLE
II
TEST RESULTS
Concentration
Date &
Phase Time
10/10 0800
Base- 0830
line 0900
0930
1000
10/10 1030
High 1100
Air 1130
1200
1230
* Total gas
** Emission
(ppm d> 3%
Flow* (ppm, dry) 0? , dry)
(SCFMD) EPA- 7 TECO EPA- 7 TECO
623,582
623,582
615,437
615,437
615,437
636,351
636,351
647,506
647,506
647,506
flow rate
518 540
517 520
550 540
560 560
524 520
503 530
518 540
464 540
538 540
573 560
542 565
541 544
568 . 552
583 583
530 526
527 555
545 569
494 575
557 559
610 596
Emission Rates
Lb/
Lb/Hr ** MMBTU*
EPA- 7
2303
2299
2413
2457
2299
2207
2350
2142
2484
2645
TECO
2401
2312
2370
2457
2282
2405
2450
2493
2493
2585
EPA- 7
.860
.858
.901
.917
.858
.826
.879
.801
.929
.990
Gm/**
* 106 ioules Lb/***
TECO
.896
.863
.884
.917
.852
.900
.917
.933
.933
.967
EPA- 7 TECO MMBTU-
.370 .
.369 .
.387 .
.394 .
.369 .
.355 .
.378 .
.344 .
.399 .
.426 .
385 .
371 .
380 .
394 .
366 .
387 .
394 .
401 .
401 .
416 .
(Duct 1 plus Duct 2) .
rates based on Duct
flow rates for each duct and
Tables III and IV,
1 concentrations
the process data
multiplied
by the total gas
utilized in the
computations
710
709
738
765
695
691
716
647
730
800
flow
are
Gm/***
105 joules
.305
.305
.317
.329
.299
.297
.308
.278
.314
.344
rate. The
shown in
respectively .
*** These emission rates were determined using "
report.
NOTE: Maxima and minima values
underlined
F Factors"
as described
in Section
V of this
for each phase.
-------
REPORT NO. Y-8479-6
PAGE 1]-
TABLE III
MILTON
YOUNG
- NORTH DAKOTA
VOLUMETRIC FLOW
Plant
Date & Load
Phase
10/7
Base-
line
10/8
Base-
line
10/8
Low
Air
10/8
Base-
Line
10/9
Base-
line
10/9
High
Air
Time (MW)
0830 251
0930
1030
1130
1230
1330
1430
0800 252
0900
1030 25.1
1130
1300 251
1400
0800 252
0900
1030 254
1130
Duct
No.
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
Duct
Temp
Gas
Flow Rates
Orsat Data Standard
Moisture Actual Dry
(°F) COp 00
309
323
300
306
309
291
302
284
289
305
269
318
259
309
327
321
326
319
327
318
317
326
333
324
328
310
308
310
314
312
320
317
341
15
14
16
16
16
16
16
16
16
16
16
15
16
16
16
15
15
.8
.8
.0
.0
.0
.0
.8
.0
.0
.3
.3
= 9
.2
.0
.1
.4
.3
-------
REPORT NO.
Y-8479-6
PAGE
12
TABLE III
J ' J~'~"" • i
MILTON YOUNG - NORTH DAKOTA
VOLUMETRIC FLOW
(Continued)
Gas Flow Rates
Plant Duct Orsat Data Standard
Date & Load Duct Temp. Moisture Actual Dry
Phase Time (MW)
10/9 1300 256
Base- 1400
line
10/10 0800 252
Base- 0900
line
10/10 1030 251
High 1130
Air
0? CO (%v/v) (ACFMW) (SCFMD)
1
2
1
2
1
2
1
2
1
2
1
2
321 16.0 3.8 .2
320
328 16.0 3.7 .0
344
313
326
309
314
312
326
319
333
16.3 3.8 .1
16.3 3.4 .2
15.9 3.6 .3
15.7 4.1 .0
12.76 591,154 311,962
615,137 319,931
613,982 321,131
614,339 313,743
12.84 592,804 311,518
601,542 312,064
579,742 308,218
581,841 307,219
12.21 618,847 327,605
591,600 308,746
617,085 323,614
626,330 323,892
NOTE: 1-A grab sample Orsat was taken every half hour. The values
resulting from the samples taken at the times shown above
were used in computing the flow rates for that particular
hour.
NOTE: 2-Two or three flue gas moisture samples were taken each day,
The first moisture value was used in the flow computations
until a new sample was taken, and this new value was then
used until the next sample was taken, etc.
STAMFORD, CONNECTICUT
-------
O
9*
«
sa
o
PS
O
O
&
*d
^*
0
^
f**
>
Tr
O
-^-fT™"--^
rVOf^
B
P
§
§
, CONNJ
icncui
TABLE IV
\
i
SUMMARY OF PLANT OPERATING DATA
MILTON
YOUNG BOILER NO . 1
OPERATING CONDITIONS
"
Date
10/ 7/74 08
10/ 8/74 08
10
13
10/ 9/74 08
10
13
10/10/74 08
10
Time
:30-14
:00-10
-.30-12
:00-15
: 00-10
:30-12
:00-15
:00-10
:30-12
Gross
MW
:30 251
:00 252
:30 251
:00 251
:00 252
:30 254
:00 256
:00 252
:30 251
Coal
Rate
Feed
(Ibs/
BTU/Lb
Coal
Hr.,as reed) as reed
409
410
409
409
410
415
417
410
409
* Measured between air heater
Type OC1530A
Analyzer.
** This value appears different
,000
,000
,000
,000
,000
,000
,000
,000
,000
6641
6341
6341
6341
6497
6497
6497
6535
6534
Gross
Heat
Input % Excess
. MMBTU/Hr Burner Air*
2716 6
2600 7
2593 2
2593 7
2664 7
2696 9
2709 6
2679 6
2673 6**
%
Excess
Total
Air* Test Phase
21 Base Line
22 Base Line
17 Low Air
22 Base Line
22 Base Line
24 High Air
21 Regular Air
21 Base Line
24 High Air
tube banks. Excess air is measured with Bailey Model A610,
than
expected
from data trend.
-------
TABLE V
COAL ANALYSIS
Date
Sample No.
BTU/Lb. (Dry)
BTU/Lb .
(as received)
Proximate
(as received)
Volatile C
Fixed C
Ash
Moisture
Proximate Dry
Volatile C
Fixed C
Ash
Ultimate (Dry)
Ash
S
N
C
H
0
F Factors
(DSCF/104 BTU)
(DSCM/104joules)
10/7
10
8,424
6,796
38.09
34.46
8.13
19.32
47.21
42.71
10.08
10.08
.49
.71
55.28
4.45
28.99
104.25
.00279
10/7
11
9,115
6,485
26.18
31.62
13.35
28.85
36.79
44.45
18.76
18.76
.57
1.04
56.11
4.29
19.23
102.1
.00275
MILTON
10/8
12
10,369
6,441
25.04
32.69
4.39
37.88
40.3-1
52.62
7.07
7.07
.46
1.07
59.42
4.59
27.39
92.0
.00246
YOUNG PLANT
10/8
13
10,189
6,240
25.64
30.31
5.29
38;76
41.87
49.50
8.63
8.63
.49
1.03
59.66
4.41
25.78
94.1
.00253
10/9
14
10,340
6,522
24.06
33.18
5.84
36.92
38.15
52.59
9.26
9.26
.64
.99
58.21
4.46
26.44
90.6
.00244
10/9
15
10,281
6,472
24.38
32.39
6.28
37.05
38.73
51.29
9.98
9.98
.47
1.03
59.00
4.42
25.10
92.6
.00248
10/10
16
10,375
6,547
23.52
34.14
5.44
36.90
37.28
54.10 '
8.62
8.62
,92
.97
60.23
4.62
24.64
94.7
.00253
10/10
17
10,407
6,523
23.30
35.12
4.26
' 37.32
37.18
56.03
6.79
6.79
.58
1.00
60.92
4.50
26.21
94.2
.00253
-------
REPORT NO. Y-8479-6 • PAGE. 15
III. PROCESS DESCRIPTION AND OPERATION
Milton R. Young Unit #1 is a 234-MW steam-electric plant which
burns crushed lignite (1/4 in. size) in a boiler designed by
Babcock and Wilcox, using cyclone burners. The boiler is de-
picted in Figure 1. There are a total of seven burners located
in two rows on the front wall of the furnace. Crushed lignite
is fired tangentially into each burner at a high velocity,
creating a vortex effect. The burner temperature is maintained
at a sufficiently high temperature to melt the fly ash and there-
by create a molten layer of ash on the inside surface of the
burner. The ash is continuously tapped from the burner and is
drained out through the bottom of the furnace. In order to
maintain the high temperatures within the cyclone, relatively
low excess air is used. Additional air is added to the hot
gases after they leave the burners, creating a form of stage
combustion. This plant was put into operation in 1970 and, at
the present time, is the only operating cyclone design firing
lignite.
During the test program, the gross electrical load and excess aii
were recorded from company instruments. Burner air was assumed
to be 85 percent of the total air flow (as recorded by the
plant). The remaining 15 percent of the total air flow was
assumed to be used for predrying the lignite and then injected
above the cyclone burners. (This air was considered "staged".)
Table IV summarizes the boiler conditions which were tested for
Milton Young #1. -Essentially, four operating configurations
were tested: baseline, low air-overfire, high air, and high air>
overfire. A copy of the process data collected can be found
in Appendix 8.
Operating conditions during any of the identified test phases
were subject to 'changes because of the nature of plant opera-
tion. An example of the reasons for this drift is that the
electrical output arid steam flow typically are maintained con-
stant within about +.05 percent by continually adjusting excess
air or burner tilt to compensate for transient slag buildup/
coal heating value, or air flow variations. This drift contri-
butes to the scatter in successive NOX measurements taken at one'
half hour intervals. Therefore, the averaged NO data corre-
sponds to an average condition representative of the range
over which the boiler conditions drifted.
STAMFORD, CONNECTICUT
-------
REPORT NO. Y-8479-6 PAGL. 16
IV. LOCATION OF SAMPLING POINTS
The sampling ports for the emission tests were located 12 feet
upstream from the nearest disturbance, a bend, and 8 feet
downstream from an expansion. The location is depicted in
Figure 1. As described by Method 1 of the December 23, 1971
Federal Register, this represents a distance of, 0.93 equivalent
diameters upstream and 0.62 equivalent diameters downstream
from these disturbances.
STAMFORD, CONNECTICUT
-------
REPORT NO. Y-8479-6
PAGE.
11
FIGURES
333 STAMFORD, CONNECTICUT
-------
STACK
COAL SILO
..-•-• \;..._
PRIMARY
SUPERHEATER
f/£¥••;. • .m-^.'-fln
I i'f' F, .SECOMBARYI-!•• v-iij.' "•.; 0
feJf.(.s=5 • SUPERICATER ,.,/;• -f .f-jr pR|MA,
1 !-|'-t -§';•' • : ''',?'V-,, |T"-'^{ ||| SUPERH1
I HP. i ^HTz'jf^
MINNKOTA POWER COOPERATIVE. INC.
CENTER POWEH PLANT -UNIT NO. I
CENTLR. NORTH DAKOTA
MILTON R. YOUNG STATION
FIGURE I
R9-
CO
-------
8'0"
h2'0"
TECO
SAMPLE
H
WHNNKOTA POWER-CORPERATIONSINC.
CENTER POWER PLANT-UNIT NO. I
FIGURE 2
-------
Y-8479-6
Page 20
CROSS SECTION
11
1
4"
— T 1 c ' -L" <-
15 v
1
j- o 3/4' ^° I 3/8'
? r
« e e o
0 0 « «
s • o »
e a i o
« o o o
e 4 e .0
» 0 e o
, ' . •
II. 3'
5.7' ' ° ° ' ' '
f U U U U
/ P v) • 4
1 tsr* f** Jlt\ ••» •»• ju\ ^J IT
12
-««.....,
II
10
9
8
7
6
5
4
3
2
1
MILTON YOUNG
P
0
I
N
T
S
FIGURE 3
-------
-------
Q
&
13
o
O
o
z
z
PI
o
G
H
EXHAUST
NO '
DRY AIR
OR
OXYGEN
PHOTO-
MULTSPL1ER
CONVERTER
KNOCK
OUT
MODE
CHEMILUMINESCENT NO-lSiO, GAS
ANALYZER a CONDITION ING SYSTEM
STRIP CHART
RECORDER
(OPTIONAL)
POWER
SUPPLY
FIGURE 5
-------
REPORT NO.
Y-8M79-6
PAGE 23
PAGES
STACK
FLUE GAS _ COLLECTION! BY
LEVELING BOTTLE
GAS FLOW
SAMPLE
GAS
VENT
.1 M
ORSAT SAMPLE ANALYSIS
VEWT
GAS FLOW
n-
•*—G AS
ORSAT
FIGURE
STAMFORD, CONNECTICUT
-------
STBCK
-------
REPORT NO. Y-8479-6
PAGE 25
AN
PIPE COUPLING TUBING ADAPTER
TVPE's" ^fc-^ /
^s
• Pilot tube-manometer assembly.
YORK RESEARCH CORPORATION
STAMFORD, CONNECTICUT
-------
REPORT NO. Y-8479-6 PAGE 26
v- SAMPLING AND ANALYTICAL PROCEDURES
The sampling at each plant consisted of the following tests:
Nitrogen Oxides - EPA Method 7
Nitrogen Oxides - NO Analyzer
Orsat - EPA Method 3X
Moisture Determination - EPA Method 4
Velocity and Flow - EPA Method 2
Nitrogen Oxides
The nitrogen oxide emissions were determined by two methods,.
The first, EPA Method 7, made use of grab flasks. The second
involved utilization of a Thermo Electron Corporation "Chemi-
luminescent NOX Analyzer."
It should be noted that EPA Method 7 procedures followed in our
nitrogen oxide sampling were those specified in a revised
Method 7 draft given York Research's Project Director before
testing began. This draft is included in the Appendix 7.
Furthermore, the sampling schedule consisted of a grab sample
taken every half-hour during the five days of testing, as is
recorded in the Field Data sheets.
As a check for trends in the NOX concentration that might have
gone unnoticed with this half-hour sampling routine, the con-
tinuous NOX analyzer was utilized., The principle of operation
for this monitor is the chemiluminescent reaction of NO and 03;
a synopsis appears below and the procedure is in Appendix 9.
To measure NO concentrations, the gas sample to be analyzed is
blended with 03 in a flow reactor. Light emission results when
electrically excited N02 molecules revert to their ground state.
The resulting chemiluminescence is monitored through an optical
filter by a high sensitivity photomultiplier positioned at one
end of the reactor. The filter-photomultiplier combination re-
sponds to light in a narrow wavelength band unique to the above
reaction. The flow parameters can be adjusted in such a way
that the output from the photomultiplier is linearly proportion-
al to the NO concentration.
To measure NOX concentration as was done for this test, the
sample gas flow was first diverted through an N02 to NO conver-
ter. By transforming any N02 in the NOX concentration to NO,
an effluent of NO was created which was linearly proportional
to the NOX concentration entering the converter. This flow
CORPORATION feslig STAMFORD, CONNECTICUT
-------
REPORT NO. Y-8479-6 PAGE. 27
could then be analyzed "by the monitor to give a reading for
ppm concentration of NOX not just NO.
A conditioning system, depicted in Figure 5, was setup before
the TECO unit for gas preparation. On extraction from the
duct, the gas was sent through a filter that removed particu-
late above 20 u. It then flowed down the probe to a cooling
coil submerged in an ice bath. At the exit of the coil a
water knockout separated and stored the condensate. The
resultant dry gas traversed a Thomas pump and a 1 u filter,
and, subsequently, was fed into the TECO unit.
The monitoring data from the analyzer was recorded on a Rustrak
Recorder. Data reduction was accomplished by obtaining the
arithmetic mean for each period of time recorded and tabulating
this as the concentration, as is shown in Table II. Maxima
and minima for each phase are also noted in Table II.
Daily calibration was performed on -the TECO unit using the manu-
facturer' s guidelines. Generally, this took placed in the
morning, though a calibration was also conducted after each
repair. It consisted of injecting a gas, analyzed as 292 ppm of
N02 on 9/27 at the York Research lab, into the analyzer after
the instrument had been zeroed. The analyzer cal adjust
setting was then changed so that the instrument output read 290.
Full calibration directions are in the instruction manual for
the Model 10B Rack Chemiluminescent NO-NO Gas Analyzer,
November 1973, Thermo Electron Corporation.
Orsat
During the testing an Orsat grab sample was taken every half
hour, at approximately the same time as the Method 7 NO
sample. The field data sheets have a single number recorded
for each gas component of these Orsat analyses.
The leveling bottle technique was used by York Research to
extract the sample from the stack and draw it into the analyzer.
Figure 6 provides an illustration. Though this system differs
from EPA Method 3 procedures, where a squeeze bulb is utilized,
it is the only dissimilarity between the sampling techniques.
The analysis was performed with 'an Orsat unit.
As noted above, a single sample was collected, analyzed, and
recorded every half hour. The Orsat values entered at the
;times indicated in Table III were used to calculate the volume-
tric flow rate for that hour. 'The concentration values, ad~
CORPORATION f$23Qra STAMFORD, CONNECTICUT
-------
REPORT NO. Y-8479-6 PAGE 28
justed to three percent 0 and shown in Tables I and II, were
corrected using the Orsat 02 value of the sample taken at
approximately the same time as the Method 7 NOX sample. This
deviates slightly from the requirements of EPA Method 3, which
stipulates that grab sampling and analysis be repeated until
three consecutive samples vary by no more than 0.5 percent,
by volume, for any gas component sampled. However, this
deviation does not significantly affect results since there
was little variation in the Orsat analyses during any specific
test phase.
Moisture
The percent moisture in the flue gas was determined with EPA
Method 4 (see Figure 7). Sampling was conducted at a single
point four feet from the stack wall for 1-^ to 3 hours at
a constant flow rate of 0.05 cfm. It was repeated during
each of the NOX test phases.
Velocity and Flow
Velocity and flow were established with EPA Method 2 (see
Figure 8). Forty-eight traverse points in each duct were
tested. This did not meet minimum EPA Method 1 requirements
since the ports were less than two equivalent diameters down-
stream from the expansion and the ratio of length to width
of the elemental equal areas was not between one and two.
However, the EPA project officer allowed the use of this site
because it was the best accessible site. The other alternative
site would have required that the sampling equipment be
carried to the 245 foot level on the stack with access by
safety ladder only. Existing ports were used even though the
length to width ratio requirement was not met; substantial
port modifications would have been required to meet this
requirement whereas minimum EPA Method 1 criteria would still
not have been fulfilled.
All measurements were performed with two pitot tubes? and
in reducing the data, the respective Cp values were averaged (to
.85 rounded from .849) for utilization in calculations and
measurements. The velocity traverse measurements were taken
every hour during the NOX sampling, starting with the first
NOX test in the morning and continuing throughout the test
day.
CORPORATION raSEC) STAMFORD, CONNECTICUT
-------
KLl-'ORT NO. Y-8479-6 ' PAGE 29
Table III is a compilation of computed velocity and flow rates.
Moisture values for each calculation were determined with EPA
Method 4, utilizing the moisture data included in the field
data sheets. Orsat values were applied to the relevant flow
computations as descri?oed in the previous subsection; and the
stack temperatures for every calculation were averaged from
the 48 points of the appropriate velocity traverse. The average
temperatures are recorded at the bottom of the velocity
traverse sheets.
Coal Sampling
There were seven feeders at Milton Young. All seven were
sampled.
During each excess air change and baseline test phase, approxi-
mately 5-10 Ibs. of coal were collected from each feeder in
regular intervals over a two hour period. Each sample was
riffled twice after collection from a feeder and the pretained
portion was added to a composite pile. At the end of each test
day the composite pile was riffled to obtain a sample for that
day.
The quartering procedure, as outlined in ASTM Method D271-68, was
used as the basis for this collection procedure.
In addition, a single grab sample was obtained daily from one o.f
the feeders and immediately sealed to prevent moisture loss.
This was felt to be more accurate than using the moisture
analysis of the daily sample because the probability and amount
of moisture loss was reduced.
As mentioned above, ASTM Method D271-68 was applied for coal
sampling and analysis. Moisture corrections were incorporated
into the coal analysis tabulation according to this method. The
HHV (high heating value, BTU/Lb) results depicted in Table V
(Section II) were established by ASTM Method D2015-66, while
the elemental analysis values were obtained through the auto-
mated Pregl Method (ASTM) with a Perkin-Elmer Model 240
elemental analyzer.
CORPORATION fc§§i STAMFORD, CONNECTICUT
-------
30
REPORT NO. Y- 847 9-6 PAGE
F Factor
In Tables I and II of Section II, F Factor emission rates have
been included. They were calculated according to the
equation:
2090
.-_ 20. 9 -
displayed in the Federal Register, Wednesday, September 11,
1974, Vol. 39, No. 177, Part II. Also outlined in this
register (60.46) were procedures for calculating the F
Factor of the coal. The equation involved was:
F = 10° [(364) (%H) + (153) (%C) + (57) (%S) + 14 (%N) - (46) (%02l|
HHV
where the HHV (high heating values) and H, C, S, N and 02 values
were determined by the ASTM methods noted above. Example
calculations with the F Factor are shown in Appendix 5.
As illustrated by the results in Tables I and II, there is a
difference between the emission rates calculated with F Factors
and those determined through measured values. The probable
explanation lies in the advantage of the F Factor itself.
Emission rates calculated by F Factor do not require measure-
ments for heat input and flow. Both are difficult to gauge
and errors in their assessment can easily be incorporated
in the subsequent measured emission rate determinations. It
is felt that this was the reason for the difference noted in
the report..
However, it is possible that the lignite samples analyzed were
not representative of the lignite being used as fuel since Type
II, condition C sampling procedures (as described in ASTM D2234-
72) were followed. Similarly, there is also the possibility
that the Orsat readings were- inaccurate. However, the close
correlation between the Orsat readings attained at North
Dakota and the nomograph supplied by A.D0 Little seems to
preclude this possibility.
YORK RESEARCH CORPORATION feS STAMFORD, CONNECTICUT
-------
REPORT NO. Y-8479-6 PAG£ 31
Extra Work
The EPA Project Officer requested that both ducts be traversed
for NOX and 02 to-check for stratification. The 02 traverses
were done 4 times, but the probe was of insufficient length to
perform the NOX traverses. No stratification was noted from
the oxygen traverses and they are included in Appendix 2.4.
During the normal-testing NOX sampling was conducted with the
TECO unit at one point in each port on both ducts. Also,
3 NOX grab samples a day were run on Duct 2, as is recorded
in the field data sheets. A comparison of the results of this
sampling is given in Table IB.
YORK RESEARCH CORPORATION feffis STAMFORD, CONNECTICUT
-------
REPORT NO. Y-81*79-6
PAGE
32
Project participants and assignments
Donald Fraser - (Project Director) -
Louis Millspaugh -
NO
(analyzer)
(Test Engineer) - NOX EPA Method 7
Ross Kittrell - (Test Engineer) - Orsat and. Moisture Tests
Kurt Mesedahl - (Test Engineer) - Velocity Traverse
Jonathan Gardner - (Test Engineer) - Velocity Traverse and
Coal Sampling
Prepared By;
;dal]
Env&ronriental Sciences
Reviewed By
Anthony Licata
Vice President
STAMFORD, CONNECTICUT
------- |