&EFK
United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EMB Report 80-NHF-15
September 1980
Air
Urea Manufacture
Emission Test Report
Union Oil Company of
California
Brea, California
-------
REPORT ON PROCESS EMISSIONS TESTS
AT THE
UNION OIL COMPANY
UREA MANUFACTURING FACILITY
IN
BREA, CALIFORNIA
Thomas M. Bibb
EPA Project Officer
Clyde E. Riley
EPA Technical Manager
EPA Contract #68-02-2820
Work Assignment #20
TRC Project I0988-E80-91
Prepared by:
Willard A. Wade III, P.E.
Project Manager
Leigh A. Ganunie
Project Engineer
Eric A. Pearson
Project Scientist
August 29, 1980
-------
PREFACE
The work reported herein was performed by personnel from TRC Environmental
Consultants, Inc. (TRC), Radian Corporation, the Union Oil Company, Brea,
California, and the U.S. Environmental Protection Agency (EPA).
The scope of work, issued under EPA Contract No. 68-02-2820, Work
Assignment No. 20, was under the supervision of the TRC Project Manager, Mr.
Willard A. Wade III. Mr. Leigh Gammie of TRC served as Project Engineer and
was responsible for summarizing the test and analytical data presented in this
report. Sample analysis was performed at the TRC laboratory in Wethersfield,
Connecticut under the direction of Mr. Samuel S. Cha.
Mr. John H.E. Stelling III of Radian was responsible for monitoring the
process operations during the emissions testing program. Radian personnel
were also responsible for preparing Section 3.0, Process Description and
Operations, of this report.
Personnel of Union Oil Company, Brea, California, whose assistance and
guidance contributed greatly to the success of this program include Mr. J.D.
Swanburg, Process Superintendent - Central Plant Engineering, and Mr. Robert
W. Waddell, Process and Control Superintendent.
Mr. Eric A. Noble, Office of Air Quality Planning and Standards,
Industrial Studies Branch, EPA, served as Test Process Project Engineer and
was responsible for coordinating the process operations monitoring.
Mr. Clyde E. Riley, Office of Air Quality Planning and Standards, Emission
Measurement Branch, EPA, served as Technical Manager and was responsible for
coordinating the emission test program.
-11-
-------
TRC-Environmental Consultants, Inc.
Willard A. Wade III, P.E,.
Project Manager
August 29, 1980
NOTE: Mention of trade names or commercial products in this publication does
not constitute endorsement or recommendation for use by the United
States Environmental Protection Agency.
-iii-
-------
TABLE OF CONTENTS
SECTION PAGE
1.0 INTRODUCTION 1
1.1 Background 1
1.2 Brief Process Description 1
1.3 Emissions Measurement Program 3
2.0 SUMMARY OF RESULTS 5
2.1 Prill Tower Emission Test Results for Northeast
Scrubber Outlet . 5
2.2 Prill Cooler Scrubber Inlet Emission Test Results . 5
2.3 Sample Collection Efficiency at the Prill Tower
Scrubber 10
2.4 Volumetric Flowrates in the Prill Tower
Scrubber Outlets 10
2.5 Pressure Drop Measurements Across the Prill Tower
Northeast Scrubber 12
2.6 Scrubber Liquor Analysis Data 12
2.7 Ambient Air Temperature and Relative Humidity
Measurements 12
3.0 PROCESS DESCRIPTION AND OPERATIONS 16
3.1 Process Equipment 16
3.2 Process Monitoring 18
3.3 General Plant Operations 24
4.0 LOCATION OF SAMPLING POINTS 26
4.1 Prill Tower Scrubber Outlet (Northeast Stack) ... 26
4.2 Prill Cooler Scrubber Inlet 26
4.3 Scrubber Liquor Common Inlet Sampling Location . . 31
4.4 Velocity Traverse Measurement Locations 31
4.5 Ambient Air Temperature and Relative Humidity
Measurement Location 31
4.6 Pressure Drop Measurement Location. . . 34
5.0 SAMPLING AND ANALYSIS METHODS 35
5.1 EPA Reference Methods Used in This Program .... 35
5.2 Urea Sampling and Analysis at the Prill Tower
Northeast Scrubber and Prill Cooler Scrubber. . . 36
5.2.1 Sampling Methods 36
5.2.2 Sample Recovery and Preparation 39
5.2.3 Sample Analysis 40
5.3 Ammonia Sampling and Analysis at the Prill Tower
Northeast Scrubber and Prill Cooler Scrubber. . . 41
5.3.1 Sampling, Sample Recovery and Preparation .... 41
5.3.2 Sample Analysis 41
5.4 Northeast Scrubber Liquor Sampling and Analysis . . 41
5.5 Volumetric Flowrate Measurements in the Northwest,
Southeast, and Southwest Scrubber Outlets .... 41
5.6 Ambient Air Temperature and Relative Humidity ... 42
5.7 Pressure Drop Measurements Across the Northeast
Scrubber 42
-iv-
-------
TABLE OF CONTENTS (Continued)
APPENDICES
A Urea and Ammonia Emission Test Results
A.I Prill Tower Northeast Scrubber Outlet
A.2 Prill Cooler Scrubber Inlet
A.3 Example Equations and Sample Calculations
B Field Data Sheets for Urea and Ammonia Testing
B.I Prill Tower Northeast Scrubber Outlet
B.2 Prill Cooler Scrubber Inlet
C Miscellaneous Field Data
C.I Scrubber Liquor Samples
C.2 Ambient Air Temperature and Relative Humidity Measurements
C.3 Velocity Traverse Data for Northwest, Southwest, and
Southeast Prill Tower Scrubber Outlets
D Daily Summary Logs
E Sampling and Analytical Procedures
E.I Urea
E.2 Ammonia
F Analytical Data
F.I Summary of Analytical Results
F.2 Summary of Analytical Procedures
F.3 Discussion of Analytical Methods and Results
F.4 Audit Samples
F.5 Clean-Up Evaluation
F.6 Sample Recovery and Preservation
F.7 Laboratory Notebook
G Sampling Train Calibration Data
G.I Orifice Calibrations
G.2 Nozzle Measurements
G.3 Pitot Tube Calibrations
H Project Participants
I Scope of Work
. Work Assignment
. Technical Directives
. Associated Correspondence
-v-
-------
• LIST OF FIGURES
FIGURES PAGE
1-1 Urea Manufacturing Process Flow Diagram, Union Oil
Company, Brea, California 2
3-1 Urea Manufacturing Process Flow Diagram, Union Oil
Company, Brea, California 17
4-1 Overhead Schematic of Prill Tower Scrubber Outlets,
Union Oil Company, Brea, California 27
4-2 Urea Prill Tower Scrubber, Union Oil Company,
Brea, California 28
4-3 Location of Sampling Points in Prill Tower Scrubber
Outlet, Union Oil Company, Brea, California .... 29
4-4 Rotary Cooler Sampling Site, Union Oil Company,
Brea, California 30
4-5 Location of Sampling Points in Rotary Cooler Inlet,
Union Oil Company, Brea, California 32
4-6 Prill Tower Scrubber Liquor Sampling Location,
Union Oil Company, Brea, California 33
5-1 Modified EPA Particulate Sampling Train 37
-vi-
-------
LIST OF TABLES
TABLE PAGE
2-la (English) Summary of Urea and Ammonia Measurements on Gases
Exiting the Prill Tower Northeast Scrubber on
April 24-25, 1980 at Union Oil Company, Brea,
California 6
2-lb (Metric) Summary of Urea and Ammonia Measurements on Gases
Exiting the Prill Tower Northeast Scrubber on
April 24-25, 1980 at Union Oil Company, Brea,
California 7
2-2a (English) Summary of Urea and Ammonia Measurements on Gases
Entering the Rotary Prill Cooler Scrubber on
April 28, 1980 at Union Oil Company, Brea,
California 8
2-2b (Metric) Summary of Urea and Ammonia Measurements on Gases
Entering the Rotary Prill Cooler Scrubber on
April 28, 1980 at Union Oil Company, Brea,
California 9
2-3 Urea Sampling Train Collection Efficiency Results,
Union Oil Company, Brea, California 11
2-4 Prill, Tower Scrubber Outlet Flow Rates at Union
Oil Company, Brea, California 13
2-5 Summary of Prill Tower Common Inlet Scrubber
Liquor Analysis Results, Union Oil Company,
Brea, California 14
2-6 Ambient Air Temperature and Relative Humidity
Measurements during Emissions Tests at Union Oil
Company, Brea, California 15
3-1 Summary of Monitored Process Operating Parameters
for the Urea Prill Tower Tests at Union Oil
Company, Brea, California 19
3-2 Summary of Monitored Process Operating Parameters
for the Emission Control Equipment at Union Oil
Company, Brea, California 21
3-3 Summary of Monitored Process Operating Parameters
for the Urea Rotary Drum Cooler Tests at Union Oil
Company, Brea, California 22
3-4 Summary of Operating Conditions and Production Rates
at Union Oil Company, Brea, California 25
-vii-
-------
1.0 INTRODUCTION
1.1 Background
Section 111 of the Clean Air Act of 1970 charges the Administrator of the
United States Environmental Protection Agency (EPA) with the responsibility of
establishing Federal standards of performance for new stationary sources which
may significantly contribute to air pollution. When promulgated, these stand-
ards of performance for new stationary sources (SPNSS) are to reflect the
degree of emission limitation achievable through application of the best
demonstrated emission control technology. Emisson data, collected from con-
trolled sources in the particular industry of concern, provide a portion of
the data base used by EPA to develop the SPNSS.
The EPA Office of Air Quality Planning and Standards (OAQPS) selected the
Union Oil Company urea manufacturing plant in Brea, California, as a site for
an emission test program. This plant produces feed and fertilizer grade urea,
and is considered to employ process and emission control technology represen-
tative of modern urea solution formation and prilling processes.
EPA engaged TRC to conduct tests designed to characterize and quantify
controlled emissions from the solids production (prill tower) and cooling
processes. Figure 1-1 shows a flow diagram of the complete urea production
process. Emission tests were performed during April 1980 at the outlet of one
of the four prill tower scrubbers and at the inlet of the rotary drum cooler
scrubber. These tests were performed during production of fertilizer grade
urea.
1.2 Brief Process Description
This facility produces feed and fertilizer grade urea, utilizing one
continuously operating prill tower. A flow diagram of the urea production
process is shown in Figure 1-1. Concentrated urea melt from the urea solution
-1-
-------
I
to
I
AMMON
* SFR1PF
CESS
IA
>ER
TO ATMOSPHERE
i 1 1 1
NSATE MAKE-UP FOR
crDiinncoc:
qq 7% IIRF
A
PRILL
TOWER
BUCKET
ELEVATOR
OFFSIZE, TO DISSOLVING TANK
TO ATMOSPHERE
ROTOCLONE
SCRUBBER
SCREEN
SCRUBBER LIQUOR TO
DISSOLVING TANK
COOLER
AGRICULTURE (FERTILIZER)
GRADE PRODUCT
FEED GRADE
PRODUCT
FIGURE 1-1 : UREA MANUFACTURING PROCESS FLOW DIAGRAM
UNION OIL COMPANY OF CALIFORNIA
BREA, CALIFORNIA
-------
formation process is pumped to a rotating chamber at the top of the prill
tower, from which the melt is sprayed downward against a countercurrent of
ambient air drawn through the tower. The falling urea droplets solidify and
the solid urea particles (prills) are removed from the bottom of the tower by
a conveyor. The fertilizer-grade product is cooled in a rotary drum cooler
and then transported to bulk storage; the feed product is transported directly
to storage. The chemical processes for producing the two product grades are
nearly identical. The prill tower operation is changed in order to produce
the smaller feed grade prills. Approximately 370 tons of fertilizer grade
urea can be produced per day at this plant.
The emissions control system used on the 150-foot high prill tower is a
group of four scrubbers located at the top of the tower. The four scrubbers
operate simultaneously and have a common sump and pump system for collecting
and recycling the scrubbing liquor. Air flow through the rotary drum prill
cooler is controlled by a rotoclone scrubber.
1.3 Emissions Measurement Program
The emissions measurement program was conducted on April 24, 25, and 28,
1980 at the Union Oil Company, urea manufacturing plant in Brea, California.
The measurement program consisted specifically of the following:
1. Urea and ammonia in the outlet gas stream of the prill tower North-
east scrubber.
2. Urea and ammonia in the inlet gas stream of the prill cooler scrubber.
3. Urea, solids content, pH, and temperature of the inlet liquor of the
prill tower Northeast scrubber.
4. Volumetric flowrates in the three prill tower scrubber outlets not
tested for emissions.
5. Ambient air temperature and relative humidity during emission tests.
-3-
-------
6. Prill tower Northeast scrubber pressure drop measurements during
emission tests.
TRC personnel were responsible for collecting the above emissions data.
Concurrently, Radian personnel were responsible for monitoring and recording
pertinent process operation parameters. The chronology of the emissions tests
is contained in the Daily Summary Logs in Appendix D.
The following sections of this report present the results of the fertiliz-
er grade emissions tests (Section 2.0), process description (Section 3.0),
location of sampling points (Section 4.0), and a discussion of the sampling
and analysis methods (Section 5.0). Detailed descriptions of methods and
procedures, field and laboratory data, and calculations are presented in the
various appendices, as noted in the Table of Contents.
Appendix F.4 contains the results of audit sample analyses. Urea stand-
ards where prepared by EPA and then analyzed by TRC in accordance with EPA
instructions in order to assess the accuracy of the urea analysis procedure.
Appendix F.5 contains the results of the cleanup evaluations performed on
the sampling train equipment. The sampling train was assembled and charged as
if ready to perform a test for urea and ammonia. The unexposed impinger con-
tents were then recovered, prepared and analyzed according to procedure in
order to establish background/contamination levels of urea from the sample
collection equipment.
-4-
-------
2.0 SUMMARY OF RESULTS
This section presents summary tables of results and narrative on the emis-
sions testing conducted April 24-28, 1980, at the Union Oil Company urea manu-
facturing facility in Brea, California. Testing was performed on the gas
stream exiting, and the liquor stream entering, one of the prill tower scrub-
bers; and on the gas stream entering the prill cooler scrubber.
Urea analyses were performed with the p-dimethylaminobenzaldehyde (PDAS)
method (with preliminary distillation). Ammonia analyses were performed with
the specific ion electrode (SIE) method. Both analysis methods are discussed
in Section 5.0 and Appendices E and F.
2.1 Prill Tower Emission Test Results for Northeast Scrubber Outlet
Table 2-1 presents the urea and ammonia results for the emission test runs
performed on the prill tower Northeast scrubber outlet gas stream. In accord-
ance with instructions from the Technical Manager, the acid impinger urea
analysis results are not included in the data shown in Table 2-1. As shown in
Appendix F.I, the acid impinger urea analysis results indicate essentially no
urea in the acid impingers. These results reflect the fact that, as discussed
in Section 2.3, all the sampled urea is caught in the first two water imping-
ers and in the probe.
2.2 Prill Cooler Scrubber Inlet Emission Test Results
Table 2-2 presents the urea and ammonia results for the emission test runs
performed on the Rotary Drum Prill Cooler scrubber inlet gas stream. As with
the prill tower scrubber data, the acid impinger urea analysis results are not
included in the data shown in Table 2-2.
-5-
-------
TABLE 2-la (English Units)
SUMMARY OF UREA AND AMMONIA TESTS
ON GASES EXITING THE PRILL TOWER NORTHEAST SCRUBBER
ON APRIL 24-25, 1980
AT UNION OIL COMPANY, BREA, CALIFORNIA
Run Number 123 Average
Date 4-24-80 4-25-80 4-25-80
Volume of Gas Sampled (DSCF)a 94.69 97.19 103.3 98.39
Stack Gas Flow Rate (DSCFM)b 13070 13730 13870 13560
Stack Temperature (°F) 77 76 77 77
Percent Moisture 4.799 4.584 5.676 5.020
Percent Isokinetic 106.3 103.9 109.3 106.5
Production Rate (Tons/Hour) 12.0 12.5 12.3 12.3
Urea Datac
Total Sample Weight (mg)
Grains/DSCF
Pounds/Hour
Pounds Aon
Ammonia Data
Total Sample Weight (mg)
Grains/DSCF
Pounds/Hour
Pounds/Ton
77.90
0.01269
1.423
0.1186
50.13
0.007959
0.9366
0.0749
61.98
0.009262
1.101
0.0895
172.4
0.0281
3.149
0.2624
195.0
0.0310
3.644
0.1518
375.5
0.0561
6.668
0.5421
63.34
0.009932
1.154
0.0938
247.6
0.0284
3.304
0.2686
aDry standard cubic feet @ 68°Ff 29.92 inches Hg.
bDry standard cubic feet per minute.
cP-dimethylaminobenzaldehyde (with preliminary distillation) Analysis Method.
"Specific Ion Electrode Analysis Method.
-6-
-------
TABLE 2-lb (Metric Units)
SUMMARY OF UREA AND AMMONIA TESTS
ON GASES EXITING THE PRILL TOWER NORTHEAST SCRUBBER
ON APRIL 24-25, 1980
AT UNION OIL COMPANY, BREA, CALIFORNIA
Run Number 1
Date 4-24-80
Volume of Gas Sampled (Nm3) a 2.682
Stack Gas Flow Rate (Nm3/Min)b 370.3
Stack Temperature (°C) 25
Percent Moisture 4.799
Percent Isokinetic 106.3
Production Rate (Mg/Hour) 6.0
Urea Datac
4-25-80
2.752
388.8
24
4.584
103.9
6.3
4-25-80
2.924
392.7
25
5.676
109.3
6.2
Average
2.786
383.9
25
5.020
106.5
6.2
Total Sample Weight (mg)
mg/Nm3
Kg/Hour
Kg/Mg
Ammonia Data
Total Sample Weight (mg)
mg/Nm3
Kg/Hour
Kg/Mg
77.90
29.05
0.6458
0.1076
172.4
64.30
1.430
0.2383
50.13
18.21
0.4252
0.0675
195.0
70.86
1.654
0.2625
61.98
21.20
0.4998
0.0806
375.5
128.4
3.027
0.4882
63.34
22.82
0.5236
0.0845
247.6
87.85
2.037
0.3285
aNormal cubic meters @ 20°C, 760 mm Hg.
formal cubic meters per minute.
cP-dimethylaminobenzaldehyde (with preliminary distillation) Analysis Method.
dSpecific Ion Electrode Analysis Method.
-7-
-------
TABLE 2-2a (English Units)
SUMMARY OF UREA AND AMMONIA TESTS
ON GASES ENTERING THE ROTARY PRILL COOLER SCRUBBER
ON APRIL 28, 1980
AT UNION OIL COMPANY, BREA, CALIFORNIA
Run Number 1 2
Date 4-28-80 4-28-80
Volume of Gas Sampled (DSCF)3 50.68 46.92
Stack Gas Flow Rate (DSCFM)b 7696 7102
Stack Temperature (°F) 127 127
Percent Moisture 2.991 3.336
Percent Isokinetic 105.1 105.5
Production Rate (Tons/Hour) 11.7 11.7
Urea Datac
4-28-80
51.52
7733
125
3.270
106.4
11.7
Average
49.71
7511
126
3.199
105.7
11.7
Total Sample Weight (mg)
Grains/DSCF
Pounds/Hour
Pounds/Ton
Ammonia Data
Total Sample Weight (mg)
Grains/DSCF
Pounds/Hour
Pounds Aon
5357
1.631
107.6
9.197
3780
1.243
75.67
6.468
4517
1.353
89.65
7.662
4551
1.413
90.96
7.774
21.70
0.006607
0.4358
0.0372
31.88
0.01048
0.6382
0.0545
36.40
0.01090
0.7225
0.0618
29.99
0.009309
0.5993
0.0512
aDry standard cubic feet @ 68°F, 29.92 inches Hg.
bDry standard cubic feet per minute.
cP-dimethylaminobenzaldehyde (with preliminary distillation) Analysis Method.
Specific Ion Electrode Analysis Method.
-8-
-------
TABLE 2-2b (Metric Units)
SUMMARY OF UREA AND AMMONIA TESTS
ON GASES ENTERING THE ROTARY PRILL COOLER SCRUBBER
ON APRIL 28, 1980
AT UNION OIL COMPANY, BREA, CALIFORNIA
Run Number 123 Average
Date 4-28-80 4-28-80 4-28-80
Volume of Gas Sampled (Nm3)a 1.435 1.329 1.459 1.407
Stack Gas Flow Rate (Nm3/Min)b 218.0 201.1 219.0 212.7
Stack Temperature (°C) 53 53 51 52
Percent Moisture 2.991 3.336 3.270 3.199
Percent Isokinetic 105.1 105.5 106.4 105.7
Production Rate (Mg/Hour) 5.9 5.9 5.9 5.9
Urea Datac
Total Sample Weight (rag)
mg/Nm3
Kg/Hour
Kg/Mg
Ammonia Data
Total Sample Weight (mg)
mg/Nm3
Kg/Hour
Kg/Mg
5357
3733
48.85
8.280
21.70
15.12
0.1979
0.0335
3780
2845
34.35
5.822
31.88
23.99
0.2897
0.0491
4517
3096
40.70
6.900
36.40
24.95
0.3280
0.0556
4551
3224
41.30
7.000
29.99
21.35
0.2719
0.0461
aNormal cubic meters @ 20°C, 760 mm Hg.
formal cubic meters per minute.
cP-dimethylaminobenzaldehyde (with preliminary distillation) Analysis Method.
Specific Ion Electrode Analysis Method.
-9-
-------
2.3 Sample Collection Efficiency at the Prill Tower Scrubber
Three emission tests runs were performed on the outlet of the Northeast
scrubber atop the prill tower. One purpose of these tests was to provide
information on the urea collection efficiency of the EPA Method 28 sampling
train.
The impinger sequence used for these tests was as follows:
impingers 1 and 2 - deionized, distilled water
impingers 3 and 4 - IN sulfuric acid
impinger 5 - empty
impinger 6 - silica gel
The probe wash, the contents of impinger 1, the contents of impinger 2, and
the combined contents of impingers 3, 4, and 5 were analyzed individually for
urea and ammonia at the TRC laboratories within 20 days of sample collection.
Urea analysis was performed using the p-dimethylaminobenzaldehyde method with
preliminary distillation. Ammonia analysis was performed using the specific
ion electrode method.
The results of the component analyses for these three prill tower scrubber
test runs are shown in Table 2-3. These data indicate that 70% of the urea in
the sampled gas is retained by the probe and first water impinger, and the
remaining urea is retained by the second water impinger. The ammonia data
indicate that half the ammonia is retained by the water impingers and half by
the acid impingers.
2.4 Volumetric Flowrates in the Prill Tower Scrubber Outlets
Velocity traverses were performed in the Southeast, Southwest, and North-
west scrubber outlets immediately before and after each emissions test run.
The calculated flowrates resulting from these velocity traverses and from the
-10-
-------
TABLE 2-3
UREA SAMPLING TRAIN COLLECTION EFFICIENCY RESULTS
UNION OIL COMPANY, BREA, CALIFORNIA
Test
Run
Urea 1 milligrams
percent
2 milligrams
percent
3 milligrams
percent
Average milligrams
percent
Ammonia 1 milligrams
percent
2 milligrams
percent >
3 milligrams
percent
Average milligrams
percent
Probe
Wash
4.50
5.8
4.83
9.6
5.58
9.0
4.97
7.8
5.43
3.1
2.83
1.5
3.10
0.8
3.79
1.5
Impinger
1
44.6
57.3
31.8
63.4
41.1
66.3
39.2
61.9
72.6
42.1
50.1 •
25.7
110
29.3
77.6
31.3
Impinger
2
28.8
36.9
13.5
27.0
15.3
24.7
19.2
30.3
26.9
15.6
40.1
20.6
63.3
16.9
43.4
17.5
Impingers
3,4,5
< 1.64*
0
< 1.58*
0
< 1.49*
0
0
67.5
39.2
102
52.2
199
53.0
123
49.7
Total
77.90
100
50.13
100
61.98
100
63.34
100
172.43
100
195.03
100
375.40
100
247.62
100
*Detection Threshold (0.010 absorbance reading). Urea standards were prepared
with similar acid contents as these acid impinger samples.
-11-
-------
Northeast scrubber emission tests are shown in Table 2-4. The total average
flowrate through the entire prill tower (all four scrubber outlets) was
approximately 49,900 dry standard cubic feet per minute.
2.5 Pressure Drop Measurements Across the Prill Tower Northeast Scrubber
Pressure drops across the prill tower Northeast scrubber were monitored
periodically (but not recorded) during each emission test run. During these
runs the pressure drop averaged approximately 2.5 inches water.
2.6 Scrubber Liquor Analysis Data
Scrubber liquor samples from the common inlet to the four prill tower
scrubbers were collected approximately every hour during each prill tower
emission test run. The liquor temperature was measured immediately after the
sample was collected, and when the sample reached room temperature the pH was
measured and recorded. After each emission test run, the samples taken during
that run were combined into one composite sample. The composite samples were
then analyzed for urea and undissolved solids. A summary of the analysis data
is shown in Table 2-5.
2.7 Ambient Air Temperature and Relative Humidity Measurements
The temperature and relative humidity of the ambient air were measured
periodically at the base of the prill tower during each emission test run.
These data are presented in Table 2-6.
-12-
-------
TABLE 2-4
PRILL TOWER SCRUBBER OUTLET FLOW RATES*
AT UNION OIL COMPANY, BREA, CALIFORNIA
Scrubber Outlet
Northeast
Time
During
Run 1
13070
Run 2
13730
Run 3
13870
Average
13560
Southeast
Southwest
Northwest
Before3
Afterb
Average
Before
After
Average
Before
After
Average
11258
11258
10496
**
10496
11814
11814
11808
12609
12208
12645
12888
12766
12076
12902
12489
12609
12150
12379
12888
12798
12843
12902
12497
12699
11892
12379
12135
12010
12843
12426
12264
12699
12481
Total Flowc
46600
51200
51800
49900
aFlow rates calculated from velocity traverses performed before the indicated
runs.
bFlow rates calculated from velocity traverses performed after the indicated
runs.
cSum of during and average flow rates, rounded to the nearest 100 DSCFM.
* Dry standard cubic feet per minute @ 68°F, 29.92 inches Hg.
**Velocity traverse data invalid due to shut down of the prill tower.
-13-
-------
TABLE 2-5
SUMMARY OF PRILL TOWER COMMON INLET SCRUBBER LIQUOR
ANALYSIS RESULTS AT UNION OIL COMPANY, BREA, CALIFORNIA
Date Run No.
Time
£H
4-25-80
4-25-80
Average 8.62
1000
1100
1130
1210
8.33
8.38
8.30
8.51
Average 8.38
1330
1430
1510
1600
8.58
8.77
8.40
8.37
Average 8.53
Measurements on Composite Samples
Temperature
4-24-80 1
1430
1515
1600
1630
8.60
8.63
8.60
8.65
83
82
82
83
83
80
82
80
82
81
82
82
81
82
82
Urea (ppm)
Undissolved
Solids(mg/1)
24300
15.5
22500
5.9
24200
64.4
-14-
-------
TABLE 2-6
AMBIENT AIR TEMPERATURE AND RELATIVE HUMIDITY MEASUREMENTS
DURING EMISSIONS TESTS AT UNION OIL COMPANY, BREA, CALIFORNIA
Wet Bulb Dry Bulb Relative Humidity
Run No. Date Time
Prill Tower 2
Prill Tower 3
All 3 Prill
Cooler Runs
4-25-80
4-25-80
4-28-80
1030
1100
1145
1330
1440
1545
1330
1640
58
58
58
59
59
60
57.5
55.5
68
68
67
70.5
70
70
63.5
51.0
54
54
58
49.5
51
56
69.5
91
-15-
-------
3.0 PROCESS DESCRIPTION AND OPERATION
3.1 Process Equipment
The urea manufacturing process consists of urea solution synthesis and
prill tower solids production/ and the process produces either feed grade or
fertilizer grade urea. A flow diagram of the process is shown in Figure 3-1.
The urea solution leaving the synthesis process is at a concentration of
about 75 percent. This solution then passes through two falling-film vacuum
evaporators in series and is concentrated to 99.7 percent. From the evapora-
tors the solution (urea melt) is pumped to a head tank at the top of the prill
tower. The melt is sprayed from a spinning bucket and the melt droplets fall
against a counter-current of ambient air drawn through the tower. As they
fall, the droplets dry to form the solid urea granules (prills) . The prills
are removed from the bottom of the tower by a conveyor and are screened.
Agriculture (fertilizer) grade product passes through a rotary drum cooler and
is then transported to bulk storage; feed grade is brought directly to bulk
storage. Offsize material is redissolved and reprocessed.
The prill tower operates 24 hours each day, 365 days per year and has an
extended production capacity of about 370 tons/day for fertilizer grade prod-
uct and 220 tons/day for feed grade product. The chemical process for both
products are nearly the same. The prill tower operation is changed in order
to produce the smaller sized feed granules.
At the top of the prill tower are four exhaust ducts, each equipped with a
fan, and each controlled by a packed bed scrubber. While fertilizer grade
prills are being produced, all four fans are in operation pulling air upward
through the tower. Air enters the tower through louvers at the base of the
prill tower. When feed grade prills are being produced, the fans are not
-16-
-------
AMMON
~* STRIPI
CESS
IA
JER
»~
NSATE MAKE-UP FOR
SCRUBBf
qq It IIRF
A
IRS
10 ATMOSPHERE
L i 1 1
PRILL
TOWER
I
BUCKET
ELEVATOR
OFFSIZE, TO DISSOLVING TANK
n
TO ATMOSPHERE
ROTOCLONE
SCRUBBER
SCREEN
SCRUBBER LIQUOR TO
DISSOLVING TANK
COOLER
AGRICULTURE (FERTILIZER)
GRADE PRODUCT
FEED GRADE
PRODUCT
FIGURE 3-1 :
UREA MANUFACTURING PROCESS FLOW DIAGRAM
UNION OIL COMPANY OF CALIFORNIA
BREA, CALIFORNIA
-------
operating but the louvers at the bottom of the tower are left open. Air flow
in the tower results from natural convection: the air in the tower is heated
by the falling prills and rises to be replaced by the cooler ambient air
entering through the louvers.
The four scrubbers atop the 150-foot high prill tower operate simultane-
ously and consist of two sections: a low pressure spray section and a high
pressure spray section. The scrubbers have a common sump and pumping system
for collecting and recycling the scrubber liquor. These scrubbers were de-
signed by Union Oil Company personnel and the design is considered proprietary.
The rotary drum cooler in the urea plant is used to supply the additional
cooling required when agricultural prills are being produced. Prills are con-
veyed through the rotary cooler by means of a series of lifting flights. Air
flow is countercurrent to prills and is induced by the Rotoclone mechanically-
aided wet scrubber. Inlet air is conditioned to remove water vapor before
introduction to the cooler.
3.2 Process Monitoring
During the emissions tests at the prill tower and prill cooler, a number
of operating parameters were monitored to ensure that process and control
equipment were operating normally. These parameters are shown in Tables 3-1
through 3-3. The numerical values of some parameters are considered confiden-
tial by the Union Oil Company. In order to indicate trends in magnitude of
operating parameters during each run and between the runs without revealing
confidential information, normalized values were calculated for these para-
meters. The normalized value is based on a deviation from a standard value.
The standard value is an average value representative of normal operation at
-18-
-------
TABLE 3-1
SUMMARY OF MONITORED PROCESS OPERATING PARAMETERS FOR
THE UREA PRILL TOWER TESTS AT UNION OIL COMPANY,
BREA, CALIFORNIA
Time3
(Minutes)
Run 1
-26
-11
0
4
19
34
49
64
79
94
109
124
139
149
Run 2
-30
-15
0
15
30
48
60
75
90
105
120
135
150
Ammonia
Feed Rate
to Reactorb
2.14
.47
.47
.47
.47
.47
.47
1.02
1.58
1.58
1.58
-.09
-.09
-.09
-2.88
-2.88
-2.88
-2.88
-.65
-.65
-.65
-.65
-.65
-.65
-.65
-.65
-.65
Carbon
Dioxide
Feed Rate
to Reactor*5
-4.80
-3.65
-3.65
-3.08
-2.50
-4.23
-4.23
-4.23
-4.23
1.51
1.51
2.66
2.66
2.66
-5.37
-5.37
-5.37
-5.37
-5.37
-5.37
-5.37
-5.37
-3.65
-.78
-2.66
-2.66
-2.66
75% Urea to
1st Stage
Evaporator
Flowrateb
.03
.03
.03
.03
.03
.03
.03
.03
.03
.03
.03
.60
1.75
1.75
.03
.03
.03
.03
.03
.03
.03
.03
.03
.03
.03
.03
.03
Level in
75% Urea
Storage Tankb
6.8
10.1
13.4
16.8
20.1
26.8
30.1
33.4
40.1
43.5
46.8
46.8
46.8
46.8
13.43
6.76
-3.25
-13.26
26.6
33.3
-40.0
-36.6
-36.6
36.6
36.6
-36.6
-36.6
Temperature
of Urea
to Head
Tank (°F)
278
278
278
278
278
278
278
278
277
278
276
280
279
278
279
279
279
279
279
279
279
279
278
278
278
278
279
-19-
-------
Run 3
TABLE 3-1 (Continued)
SUMMARY OF MONITORED PROCESS OPERATING PARAMETERS FOR
THE UREA PRILL TOWER TESTS AT UNION OIL COMPANY,
BREA, CALIFORNIA
(Continued)
Time3
(Minutes)
Ammonia
Feed Rate
to Reactor*3
Carbon
Dioxide
Feed Rate
to Reactorb
75% Urea to
1st Stage
Evaporator
Flowrateb
Level in
75% Urea
Storage Tankb
Temperature
of Urea
to Head
Tank (°F)
-15
0
15
30
45
60
75
90
105
120
135
150
-.09
-.09
-.09
-.09
-.09
-.09
-.09
-.09
-.09
-.09
-.09
-.09
-4.95
-4.38
-4.38
-4.38
-4.38
-4.38
-4.38
-3.80
-2.66
2.66
2.66
2.66
.03
.03
.03
2.89
2.32
1.18
.60
.60
.60
.32
.03
.03
-26.6
-23.3
-19.9
-16.6
-13.3
-9.9
-6.6
-6.6
-6.6
-6.6
-6.6
— o • 6
286
279
281
279
280
278
278
278
278
279
277
279
aDates and times corresponding to t =
0 were as follows: Run 1 - 4/24/80, 1426
Run 2 - 4/25/80, 0945
Run 3 - 4/25/80, 1330
Values reported as % deviation from standard value = [(xt - xs)/xs]xlOO
-20-
-------
TABLE 3-2
SUMMARY OF MONITORED PROCESS OPERATING PARAMETERS
FOR THE UREA PRILL TOWER EMISSION CONTROL EQUIPMENT
AT UNION OIL COMPANY,
BREA, CALIFORNIA
Time3
(Minutes)
Run 1
-11
0
4
34
64
94
124
154
Run 2
-15
0
45
75
105
135
Run 3
-15
0
30
60
90
120
Scrubber
Liquor
Make Up
Flowrateb
4.93
4.93
4.93
6.01
2.76
8.17
3.85
4.93
-1.56
.48
-1.56
-1.56
-1.56
-.48
-4.81
-1.56
-6.97
-4.81
-4.81
-5.89
High
Pressure
Spray
Flowrateb
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Low
Pressure
Spray
Flowrateb
.87
.87
.87
-.68
.87
.87
-.68
-.68
-.68
-.68
-.68
-.68
-.68
-.68
.87
.87
aDates and times corresponding to t = 0
were as follows: Run 1 - 4/24/80, 1426
Run 2 - 4/25/80, 0945
Run 3 - 4/25/80, 1330
bValues reported as % deviation from standard value = [(xt - xs)/xs]xlOO
-21-
-------
TABLE 3-3
SUMMARY OF MONITORED PROCESS OPERATING PARAMETERS FOR
THE UREA ROTARY DRUM COOLER TESTS AT UNION OIL COMPANY,
BREA, CALIFORNIA
Time
(Minutes)
Run 1
-14
0
16
31
46
61
76
91
Run 2
-25
0
20
35
50
65
80
95
110
Run 3
-13
0
17
32
47
62
77
92
99
Ammonia
Feed
Rate
t0 b
Reactor
-.65
.47
.47
.47
.47
.47
.47
.47
-.09
-.09
-.09
-.09
-.09
-.09
-.09
-.09
-.09
-.09
-.09
-.09
-.47
-.47
-.47
-.47
-.47
-.47
Carbon
Dioxide
Feed
Rate
t° b
Reactor
-1.36
-1.36
-1.36
-1.36
-1.36
-1.36
-1.36
.94
.36
.36
.36
.36
.36
.36
.36
.36
.36
.36
.36
-.21
-.21
-.21
-.21
.36
.94
.94
75% Urea to
1st Stage
Evaporator
Flowrateb
-.83
-.83
-.83
-.83
-.83
-.83
-.83
-.83
-.25
-.25
-.25
-.25
-.25
-.25
-.25
-.25
-.25
-.25
-.25
. .03
.03
.03
.03
.03
.03
.03
Level to
75% Urea
Storage
Tankb
.08
.08
.08
.08
.08
.08
.08
.08
3.42
3.42
3.42
3.42
3.42
3.42
3.42
3.42
3.42
3.42
3.42
3.42
3.42
3.42
3.42
3.42
3.42
3.42
Temp.
Temp. Product Temp.
Air from Product
Into Prill from
Cooler Tower Cooler
(0F) (0F) (op)
64 157 123
64
65
64
64
78
76 195 139
73
74
72
183 134
71
71
70
191 136
72
72
aDates and times corresponding to t = 0 were as follows: Run 1 - 4/28/80, 1214
Run 2 - 4/28/80, 1640
Run 3 - 4/28/80, 1913
bValues reported as % deviation from standard value = [(xt - xs)/xs]xlOO
-22-
-------
the operating capacity during the tests. These normalized values were calcu-
lated by subtracting the standard value of a parameter from the value for the
parameter at a given time and dividing by the standard value.
Actual and normalized values for process operating parameters monitored
during prill tower testing are reported in Table 3-1. Normalized values for
operating parameters of the Northeast scrubber during prill tower testing are
reported in Table 3-2. Standard values for these parameters are contained in
the confidential files.
Synthesis process parameters (carbon dioxide flowrate to reactor and
ammonia flowrate to reactor) were recorded as indicators of overall urea
production. The flowrate of 75 percent urea to the first evaporator was used
as an indicator of urea melt and solids production. Changes in the level of
the 75 percent urea storage tank accompanied changes in the urea synthesis
process. The temperature of the urea melt pumped to the head tank was also
used as an indicator of normal operation.
During the prill tower emissions tests scrubber liquor samples were col-
lected and analyzed for urea and solids content, as well as temperature and
pH, in order to characterize variations in the scrubber liquor during each
test run. Pressure drops were monitored periodically and were constant at
about 2.5 inches water. Although formal visible emissions observations were
not made during these emissions tests, scrubber outlet opacities were estimat-
ed to range between 5 and 10 percent, depending on time of day.
Actual and normalized values for process operating parameters monitored
during the cooler emissions tests are shown in Table 3-3. Standard values for
these parameters are contained in the confidential files. Inlet air and prod-
uct temperatures were used as indicators of stable cooler operations
-23-
-------
During Cooler Run 1 on April 28, 1980, there was a shift in the inlet air
temperature resulting from an increase in steam flow to the air precondition-
ing system. This had no apparent effect on cooler outlet air temperature.
During the first traverse of Cooler Run 2, the air flow was noticeably
reduced from the previous velocity traverses. The lower air flow was the
result of caking in the outlet duct from the control device. This duct was
cleaned before continuing with the final traverse for Cooler Run 2. Thus, the
overall average air flowrate for Cooler Run 2 was lower than for the other two
cooler tests. Washing out cooler ducts is a standard practice at this urea
plant.
3.3 General Plant Operations
Operating conditions and production rates during tests are summarized in
Table 3-4. Based upon observations of pertinent operating parameters, all 3
tests on the prill tower are representative of normal conditions. Test 2 on
the rotary drum cooler is expected to show a slightly reduced air flow rate.
However, this should be considered representative of normal operations.
-24-
-------
TABLE 3-4
SUMMARY OF OPERATING CONDITIONS AND PRODUCTION RATES AT
UNION OIL COMPANY, BREA, CALIFORNIA
Prill Tower
Prill Cooler
Production Rate3
(percent capacity)
Anomalies in
Operations
Run 1 Run 2
>90 >90
None
None
Run 3
>90
None
Run 1 Run 2 Run 3
>89 >89 >89
None airflow none
reduced13
aProduction rates are approximations
'•'Caking in outlet duct during first traverse
PRODUCTION RATES OF UREA PRILLING DURING EMISSIONS TESTING
24-28 April 1980
Test Location
Prill Tower
Prill Tower
Prill Tower
Prill Cooler
Prill Cooler
Prill Cooler
Date
24 April 1980
25 April 1980
25 April 1980
28 April 1980
28 April 1980
28 April 1980
Time Period of Test
2 :26 pm - 4:55 pm
9:45 am - 12:15 pm
1:30 pm - 4:00 pm
12:14 pm - 1:45 pm
4:40 pm - 6:30 pm
7:13 pm - 8:52 pm
Production Rate
(tons per day)
289
300 (8:00 am)
295 (1:00 pm)
280 (12 Noon)
280 (4:00 pm)
280 (7:00 pm)
-25-
-------
4.0 LOCATION OF SAMPLING POINTS
Four fiberglass scrubbers are located atop the prill tower at the Union
Oil Company facility. All four scrubbers are of similar design and construc-
tion. The scrubber located on the Northeast corner of the prill tower was
recommended for testing by Union Oil personnel. An overhead schematic of the
four scrubber outlet stacks is shown in Figure 4-1.
4.1 Prill Tower Scrubber Outlet (Northeast Stack)
The cleaned gases exiting the scrubber unit pass through a 4-foot section
of 47-inch I.D. duct and then to the atmosphere. This duct was fitted with
two 4-inch I.D. pipe-flange sampling ports positioned 90 degrees apart in a
horizontal plane. The ports were located 24 inches downstream from a duct
transition and 24 inches upstream from the duct discharge. Since these port
locations did not meet the "eight and two diameters" criteria of EPA Reference
Method 1, 24 sampling points were chosen for each traverse axis, for a total
of 48 sampling points as specified by Method 1. Figure 4-2 shows a schematic
of the scrubber and sampling locations. Figure 4-3 shows a cross-sectional
view of the outlet duct at the sampling location and lists the exact distance
of each sampling point from the outside flange edge.
4.2 Prill Cooler Scrubber Inlet
Sampling for urea particulate was conducted at the inlet of the prill
cooler rotoclone scrubber in a 24-inch I.D. steel duct. A schematic of the
sampling location is shown in Figure 4-4.
The inlet duct was fitted with two 3-inch I.D. pipe-flange sampling ports
positioned 90 degrees apart in a vertical plane. The nearest upstream dis-
turbance was an in-line damper located 55 inches from the ports. The
-26-
-------
N
t
LADDER
FIGURE 4-1: OVERHEAD SCHEMATIC OF PRILL TOWER SCRUBBER OUTLETS
AT UNION OIL COMPANY, BREA, CALIFORNIA.
0988-014
-27-
-------
SCRUBBER WATER IN
74"
16"
48"
PRILL TOWER
OUTLET SAMPLING PORTS
SCRUBBER WATER IN
SCRUBBER
^ JUrtUDDCri
-S> WATER OUT
FAN MOTOR
FIGURE 4-2: UREA PRILL TOWER SCRUBBER
UNION OIL COMPANY,
BREA, CALIFORNIA
-28-
-------
PORT 1
TRAVERSE POINT TRAVERSE POINT LOCATION
NO.
FROM OUTSIDE FLANGE (IN.)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
3-1/2
3-1/2
4-1/2
5-3/4
7
8-1/2
9-1/2
11
12-3/4
14-3/4
17
20-3/4
30-1/4
34
36-1/4
38
40
41-1/2
42-3/4
44
45-1/4
46-1/2
47-1/2
47-1/2
FIGURE 4-3: LOCATION OF SAMPLING POINTS IN UREA PRILL TOWER SCUBBER OUTLET
UNION OIL COMPANY, BREA, CALIFORNIA.
-29-
0988-016
-------
LO
O
I
FERTILIZER
UREA COOLER
r:
DAMPER
f -i
36"
99"
OUTLET DUCT
23
" '
•55'i-
SAMPLING PORTS
F
47"-
TO ROTOCLONE
SCRUBBER
FIGURE 4-4: PRILL COOLER SCRUBBER INLET SAMPLING SITE AT UNION OIL COMPANY,
BREA, CALIFORNIA.
0988-017
-------
nearest downstream disturbance was a short-radius 90 degree bend 47 inches
from the ports. The "eight and two diameters criteria" could not be met,
hence 16 sampling points were chosen for each traverse axis, for a total of 32
sampling points as specified by EPA Reference Method 1. Figure 4-5 shows a
cross-sectional view of the cooler inlet duct at the sampling location and the
exact distance of each sampling point from the outside flange edge.
4.3 Scrubber Liquor Common Inlet Sampling Location
The prill tower scrubber liquor collects in a common sump and is then
circulated to the four scrubbers through two pump systems: a high pressure
system and a low pressure system. The scrubber liquor samples were taken from
an existing valve downstream from the circulating pump. Figure 4-6 shows the
location of this sampling site.
4.4 Velocity Traverse Measurement Locations
Velocity head and temperature measurements were made in the three prill
tower scrubber outlets not tested for emissions. These measurement locations
were identical to the sampling location in the Northeast scrubber outlet as
shown in Figures 4-2 and 4-3.
4.5 Ambient Air Temperature and Relative Humidity Measurement Location
Ambient air temperature and relative humidity measurements were made
periodically during the emissions testing program from a location near the
base of the prill tower. This location was approximately 30 feet from the
Northwest side of the prill tower directly across from one of the tower air
inlets.
-31-
-------
PORT 2
PORT 1
TRAVERSE POINT
NO.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
TRAVERSE POINT LOCATION
FROM OUTSIDE FLANGE (IN.)
2-3/4
3
3-3/4
4-3/4
5-3/4
7
8-1/2
10-1/2
16-1/2
18-3/4
20-1/4
21-1/2
22-1/2
23-1/2
24-1/4
24-1/2
FIGURE 4-5: LOCATION OF SAMPLING POINTS IN PRILL COOLER INLET AT UNION. OIL
COMPANY, BREA, CALIFORNIA.
0988-018
-32-
-------
TO SCRUBBERS
FROM
SUMP
NE
SE
SW
XXX
NW
PUMP
2" STAINLESS
STEEL LINES
ROTAMETERS
LINE
PRESSURE
GAUGE
•DX)
SCRUBBER
WATER SAMPLE
COLLECTION
POINT
FIGURE 4-6: UREA PRILL TOWER SCRUBBER LIQUOR SAMPLING LOCATION AT UNION OIL
COMPANY, BREA, CALIFORNIA.
0988-019
-33-
-------
4.6 Pressure Drop Measurement Location
Pressure drops across the prill tower Northeast scrubber were made with a
vertical U-tube water manometer. One side of the manometer was connected to a
pressure tap inserted into the scrubber inlet duct approximately 12 feet below
the scrubber. The other side of the manometer was open to the atmosphere.
-34-
-------
5.0 SAMPLING AND ANALYSIS METHODS
This section presents general descriptions of sampling and analysis proce-
dures employed during the emissions testing program conducted at the Union Oil
Company, Brea, California urea manufacturing facility during April 24-28,
1980. Details of sampling and analysis procedures are contained in Appendices
E and F.
5.1 EPA Reference Methods Used in This Program
The following EPA Reference Methods were used during this emission testing
program. These methods are taken from "Standards of Performance for New
Stationary Sources", Appendix A, Federal Register, Volume 42, No. 160, Thurs-
day, August 18, 1977, pp 41755 ff.
o Method 1 - Sample and Velocity Traverses for Stationary Sources
This method specifies the number and location of sampling points within
a duct, taking into account duct size and shape and local flow disturb-
ances .
o Method 2 - Determination of Stack Gas Velocity and Volumetric Flowrate
This method specifies the measurement of gas velocity and flowrate
using a pitot tube, manometer and temperature sensor. The physical
dimensions of the pitot tube and its spatial relationship to the temp-
erature sensor and any sample probe are also specified.
o Method 4 - Determination of Moisture Content in Stack Gases
This method describes the extraction of a gas sample from a stack and
the removal and measurement of the moisture in that sample by condensa-
tion impingers. The assembly and operation of the required sampling
train is specified.
The emissions tests and sample analyses were performed using EPA Reference
Method 28, Determination of Particulate (Urea) Emissions from Urea Plants.
This method incorporates modifications to EPA Reference Method 5, Determina-
tion of Particulate Emissions from Stationary Sources, that reflect the char-
-35-
-------
acteristics of urea and urea sources. With Method 5 as a reference, Method 28
specifies the isokinetic sampling of urea particulate from a gas stream
utilizing techniques introduced in Methods 1, 2, and 4. Sample collection and
recovery, sampling train cleaning and calibration, and gas stream flowrate
calculations procedures are specified. No filter is used in the sampling
train. Analysis of impinger samples for urea is performed with the
p-dimethylaminobenzaldehyde method. Method 28 is described in its entirety in
Appendix E.
5.2 Urea Sampling and Analysis at the Prill Tower Northeast Scrubber and Prill
Cooler Scrubber
5.2.1 Sampling Methods
Urea and ammonia in the outlet gas stream of the prill tower Northeast
scrubber and inlet gas stream of the prill cooler scrubber were sampled at
points located in accordance with EPA Method 1. Duct gas velocities were
measured using S-type pitot tubes constructed and calibrated in accordance
with EPA Method 2.
The sampling train used on this program is shown in Figure 5-1 and is a
modification to the particulate sampling train specified in EPA Method 28.
The modifications used were: two water impingers (instead of three), two acid
impingers (instead of one), use of an empty impinger, and use of a Teflon
line. No filter is used in the sampling train.
The sampling train shown in Figure 5-1 consists of a nozzle, probe, Teflon
line, six impingers, vacuum pump, dry gas meter, and an orifice flow meter.
The nozzle is stainless steel and of buttonhook shape. The nozzle was con-
nected to a 5/8-inch stainless steel glass-lined probe wrapped with nichrome
heating wire and jacketed. Following the probe, the gas stream passed through
a 3/8-inch I.D. teflon line into an ice bath/impinger system. The impinger
system consisted of six impingers in series. The first, third, fifth and
-36-
-------
STACK WALL
THERMOMETER
U)
vj
I
LEGEND
1 - NOZZLE 7
2 - PROBE 8
3 - TEFLON LINE 9
4 - ICE BATH 10
5 - FLEXIBLE LINE 11
6 - VACUUM GAGE 12
NEEDLE VALVE
PUMP
DRY GAS METER
ORIFICE
PITOT TUBE & INCLINED MANOMETER
POTENTIOMETER
FIGURE 5-1: MODIFIED EPA PARTICULATE SAMPLING TRAIN
-------
sixth impingers were the Greenburg-Smith design, modified by replacing the tip
with a one-half inch glass tube extended to within one-half inch of the
impinger bottom. The second and fourth impingers were of regular Greenburg-
Smith design including tips with orifice plates located within one-half inch
of the impinger bottom. The first two impingers contained deionized, distil-
led water (100 mis each). The next two impingers contained IN H SO. (100
mis each). The fifth impinger was empty, and the sixth contained 200 grams of
indicating silica gel. Leaving the last impinger, the sample stream flowed
through flexible tubing, a vacuum gauge, needle valve, pump, and a dry gas
meter. A calibrated orifice and inclined manometer completed the train. The
stack velocity pressure was measured using a pitot tube and inclined mano-
meter. Stack temperature was monitored by. a thermocouple attached to the
probe and connected to a potentiometer. A nomograph was used to determine the
orifice pressure drop required for any pitot velocity pressure and stack
temperature in order to maintain isokinetic sampling conditions.
The probe temperature was maintained at about 10 F above the stack gas
temperature in order to prevent condensation within the probe.
Test data recorded at each sampling point included test time, sampling
duration at each traverse point/ pitot pressure, stack temperature, dry gas
meter volume and inlet-outlet temperature, probe temperature and orifice
pressure drop.
The only significant sampling problem occurred at the prill cooler scrub-
ber inlet. The test runs were frequently interrupted by pitot tube tip plug-
ging due to the heavy particulate loading. Because of this problem, test run
1 at the prill cooler scrubber inlet was performed utilizing the velocity head
readings obtained from the preliminary velocity traverse. During test runs 2
and 3, the pitot was blown clear with compressed air each time it plugged.
-38-
-------
5.2.2 Sample Recovery and Preparation
Prill Tower Samples
At the completion of each test run, the train was leak checked. Then the
nozzle, probe and flexible Teflon line were washed with deionized, distilled
water (three times). The volume of the contents of each impinger was
measured, and the samples were put in glass containers with Teflon-lined caps
as follows:
Jar #1 - nozzle, probe, and Teflon line washes.
Jar #2 - contents of the first impinger and the distilled water wash of
the impinger and its glassware connector.
Jar #3 - contents of the second impinger and the distilled water wash of
the impinger and its glassware connector.
Jar #4 - contents of the third, fourth, and fifth impingers and the IN
H2S04 wash of these impingers and their connecting glass-
ware.
Jar 15 - silica gel from the sixth impinger.
These sample containers were then returned to TRC for urea and ammonia
analysis. Only jars 1 and 2 in run 1 contained some rust-colored particulate
matter, possibly pipe scale, which was filtered out before sample analysis.
All other samples were clear.
Prill Cooler Samples
At the completion of each test run the train was leak checked. Then the
nozzle, probe and flexible Teflon line were washed with deionized, distilled
water (three times). Samples were put in glass containers with Teflon-lined
caps, as follows:
Jar #1 - contents of the first two impingers, and the deionized, dis-
tilled water wash of their connecting glassware and the nozzle,
probe and Teflon line.
-39-
-------
Jar #2 - contents of the third, fourth, and fifth impingers and the IN
H2S04 rinse of the impingers and their connecting glassware.
Jar 13 - silica gel from the sixth impinger.
These sample containers were returned to TRC for urea and ammonia analysis.
Rust-colored particulate matter was noted in the Jar 1 samples from test runs
2 and 3. These samples were filtered prior to analysis.
i
5.2.3 Sample Analysis
All samples were analyzed at the TRC laboratory within 20 days after col-
lection. At TRC, the volume of the contents of each sample jar was measured.
Each individual water sample (jars 1, 2, and 3 for the prill tower and jar
1 for the prill cooler) was analyzed for urea with the p-dimethylaminobenzal-
dehyde (PDAB) method with preliminary distillation. For the urea analysis, a
sodium borate buffer and NaOH were added to each sample to adjust the pH to
9.5 or greater. The samples were then boiled to remove ammonia and the PDAB
color reagent was added to the residue. The solution absorbances were then
measured in a spectrophotometer.
The acid samples (jar 4 for the prill tower and jar 2 for the prill cool-
er) were analyzed for urea by the same PDAB method. An additional 1 ml con-
centrated hydrochloric acid per liter of sample was added to acid impinger
sample solutions prior to the absorbance readings to remove the turbidity that
resulted upon addition of the PDAB color reagent.
Urea standards were prepared with the same acid content as the samples.
Sample absorbances were converted to urea concentration with the calibration
curve drawn from the analysis of these standards.
-40-
-------
5.3 Ammonia Sampling and Analysis at the Prill Tower Northeast Scrubber and
Prill Cooler Scrubber
5.3.1 Sampling, Sample Recovery and Preparation
The same samples collected and recovered as described in Sections 5.2.1
and 5.2.2 were analyzed for ammonia as well as urea.
5.3.2 Sample Analysis
The water portions and the acid portions were analyzed for ammonia content
by the specific ion electrode (SIE) method. An Orion model 95-10 ammonia
electrode was used in accordance with the electrode manufacturer's proce-
dures. This method is extremely specific for ammonia and is subject to few,
if any, interferences. All ammonia analyses were performed at the TRC
laboratory within 20 days of collection.
5.4 Northeast Scrubber Liquor Sampling and Analysis
Four 100-ml liquor samples were collected during each of the emission test
runs at the prill tower scrubber outlet. The temperature of each liquor
sample was measured immediately following its collection. Once the sample
reached room temperature, the pH was measured. The samples collected during a
test run were then combined to form one composite sample per run.
At the TRC laboratory, the composite samples were filtered using a tared
glass fiber filter in order to remove undissolved material. The urea analysis
was performed using the PDAB method as discussed in Section 5.2.3. The solids
analysis was performed by desiccating and weighing the filter to a constant
weight.
5.5 Volumetric Flowrate Measurements in the Northwest, Southeast, and
Southwest Scrubber Outlets
Velocity traverses were performed at the Northwest, Southeast, and
Southwest scrubber outlets before and after each emission test run at the
-41-
-------
Northeast scrubber outlet. Two perpendicular traverses were performed at each
outlet during each velocity test, with velocity head and stack gas temperature
measured at each sampling point, in accordance with EPA Reference Method 2.
The duct static pressure and percent moisture values obtained from the
Northeast outlet were applied on a run-by-run basis to the other three outlets
in order to compute volumetric flowrates. Velocity head and temperature
measurement data are contained in Appendix C.
5.6 Ambient Air Temperature and Relative Humidity
Ambient air temperature and relative humidity were recorded periodically
at the base of the prill tower during the emission testing program. Wet bulb
and dry bulb temperature measurements were made with a Bendix psychron.
Psychrometric tables were then used to compute relative humidity from these
measurements.
5.7 Pressure Drop Measurements Across the Northeast Scrubber
Pressure drop measurements across the prill tower Northeast scrubber were
observed but not recorded. During the first test run, it was apparent that
the pressure drop was very small and very steady. Under the direction of the
Technical Manager the pressure drop readings were monitored during each test
run. One side of a vertical U-tube water manometer was connected to a
pressure tap inserted into the scrubber inlet duct approximately 12 feet below
the scrubber. The other side of the manometer was open to the atmosphere.
-42-
------- |