x>EPA
United States Industrial Environmental Research EPA-600/7-78-158
Environmental Protection Laboratory August 1978
Agency Research Triangle Park NC 2771 1
Sampling System
Evaluation for
High-temperature,
High-pressure
Processes
Interagency
Energy/Environment
R&D Program Report
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5, Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from the
effort funded under the 17-agency Federal Energy/Environment Research and
Development Program. These studies relate to EPA's mission to protect the public
health and welfare from adverse effects of pollutants associated with energy sys-
tems. The goal of the Program is to assure the rapid development of domestic
energy supplies in an environmentally-compatible manner by providing the nec-
essary environmental data and control technology. Investigations include analy-
ses of the transport of energy-related pollutants and their health and ecological
effects; assessments of, and development of, control technologies for energy
systems; and integrated assessments of a wide range of energy-related environ-
mental issues.
REVIEW NOTICE
This report has been reviewed by the participating Federal Agencies, and approved
for publication. Approval does not signify that the contents necessarily reflect the
views and policies of the Government, nor does mention of trade names or commercial
products constitute endorsement or recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
-------
EPA-600/7-78-158
August 1978
Sampling System Evaluation
for High-temperature, High-pressure
Processes
by
William Masters, Robert Larkin, Larry Cooper, and Craig Fong
Acurex Corporation/Energy and Environmental Division
485 Clyde Avenue
Mountain View, California 94042
Contract No. 68-02-2153
Program Element Nos. EHE623 and 624
EPA Project Officer: William B. Kuykendal
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
-------
TABLE OF CONTENTS
Section Page
1. INTRODUCTION 1
2. OVERVIEW OF RESULTS 3
2.1 Phase I ~ Demonstration Tests 3
2.2 Phase II — Condensation Tests 4
3. EQUIPMENT DESCRIPTION 7
3.1 Sampling System 7
3.1.1 Phase I ~ Demonstration Tests 7
3.1.2 Phase II -- Condensation Tests 44
3.2 Exxon Miniplant Test Facility 53
4. TEST DESCRIPTION 60
4.1 Phase I — Demonstration Tests 60
4.1.1 Procedures 50
4.1.2 Pretest Activities 51
4.1.3 First Run 61
4.1.4 Second Run 62
4.1.5 Third Run 62
4.1.6 Post-Test Activities 63
4.2 Phase II -- Condensation Tests 63
4.2.1 Procedures 63
4.2.2 Pretest Activities 63
4.2.3 Runs 1 and 2 64
Runs 3 and 4 65
4.2.5 Post-Test Activities 65
5. DATA AND RESULTS ' 66
5.1 Phase I ~ Demonstration Test Data 66
5.1.1 Test Conditions 66
5.1.2 Instrument Readings 66
5.2 Phase I — Demonstration Test Results 73
5.3 Phase II ~ Condensation Test Data 78
5.3.1 Test Conditions 78
5.3.2 Instrument Readings 98
-------
TABLE OF CONTENTS (Concluded)
Section Page
5.4 Phase II — Condensation Test Results 102
5.4.1 General Results and Observations 104
5.4.2 Initial Analyses for Condensation Effects ... Ill
5.4.3 Alternate Approach 122
6 CONCLUSIONS 126
REFERENCES 128
-------
LIST OF ILLUSTRATIONS
Figure Page
3-1 High-temperature, high-pressure sampling system 11
3-2 System schematic 13
3-3 Exploded view of HTHP probe 15
3-4 Aerotherm HTHP sampling probe and duct interface
valve 19
3-5 Access valves 21
3-6 HTHP probe housing/side view 23
3-7 HTHP probe housing/end view 24
3-8 HTHP probe/side view/front half 25
3-9 HTHP probe/side view/back half . 27
3-10 HTHP probe rear access plate and controls/side
and end view 28
3-11 HTHP probe rear access plate and controls/top view ... 29
3-12 Dowtherm system 30
3-13 Dowtherm console 31
3-14 Gas sampler train - flow control oven 34
3-15 Oven assembly 35
3-16 Organic cartridge 37
3-17 Organic module 38
3-18 Organic module — exploded view 39
3-19 Flow control oven and gas train 41
3-20 Organic module and impinger bottles 43
3-21 Control consoles 45
3-22 Probe configurations 47
3-23 Scalping cyclone assembled 49
vii
-------
LIST OF ILLUSTRATIONS (Continued)
Figure Pa9e
3-24 Scalping cyclone disassembled 50
3-25 Transport tube 52
3-26 Pressurized fluidized bed coal combustor system .... 54
3-27 HTHP probe assembly installed at Exxon miniplant .... 57
5-1 Probe inlet bias 72
5-2 Particle size distribution 76
5-3 Impactor substrates 79
5-4 Impactor substrates 81
5-5 Impactor substrate — Run 3, Stage 5 83
5-6 Impactor substrate — Run 2, Stage 5 85
5-7 Particle photomicrographs Stage 1 87
5-8 Particle photomicrographs Stage 2 89
5-9 Particle photomicrographs Stage 4 91
5-10 Particle photomicrographs Stage 6 93
5-11 Particle chemical composition 95
5-12 Condensation of H2S04 101
5-13 Particle Photomicrographs -- Run 1, front filter .... 107
5-14 Particle photomicrographs -- Run 4, front filter .... 109
5-15 Particle photomicrographs -- Run 4, rear filter .... 113
5-16 Particle photomicrographs — Run 1, rear filter .... 115
5-17 Particle chemical composition — blank rear filter ... 117
5-18 Particle chemical composition -- Run 4 119
vm
-------
LIST OF TABLES
Table
3-1
3-2
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
5-10
5-11
5-12
5-13
5-14
Sampling System Capabilities
Utility Requirements
Test Conditions
Phase I Probe Instrumentation Readings
Gas Train Instrument Readings
Anisokinetic Correction Factors — Phase I
Structure Temperatures
Parti cul ate Content
Particle Size Distribution
Exxon ~ Phase II FBC Operating Conditions
Probe Instrumentation Readings
Anisokinetic Correction Factors ~ Phase II
Particulate Concentration
Visual Observation of Filters — Phase II
Concentration of Elements in Flyash SSMS
Analysis (Partial)
Partial Comparison of Front and Rear Particulate ....
Catches from Exxon Test Series I and II
Page
9
59
67
68
69
70
74
75
77
97
99
103
105
106
123
124
IX
-------
SECTION 1
INTRODUCTION
Advanced coal conversion processes present new problems in parti -
culate sampling, including severe environments beyond the capabilities of
conventional equipment.
Fluidized bed combustion and coal gasification processes emit
gases containing large quantities of fine particles. These particles
must be removed to prevent damage to process equipment (mainly turbines)
and to eliminate potential environmental pollution. Development of par-
ticulate removal equipment is an important step toward making advanced
coal conversion processes practical. The sampling system described in
this report is one of the first tools available for measuring the collec-
tion efficiency of fine particle removal devices operating in high-
pressure, high-temperature environments. The sampling system described
in this report is specifically designed for the high temperatures and
pressures found in pressurized fluidized bed combustors (PFBC). The
system uses an extractive sampling approach, withdrawing samples from the
process stream for complete analysis of particulate concentration, shape,
size, and chemical composition. The capabilities of the new system have
been demonstrated in two phases of sampling operations at Exxon
Corporations pilot-scale pressurized, fluidized bed combustion Miniplant
located in Linden, New Jersey. The first phase of testing was performed
-------
during the week of March 21, 1977 with the sample probe in its basic
configuration. The second test phase used modified probe internals
designed to investigate possible condensation of alkali metals as a
result of cooling the sample prior to collection. These tests were
performed the week of May 23, 1977. The system performed successfully in
a variety of operating modes, producing sample data from both test series.
Acurex has developed the HTHP sampling system for the Industrial
Environmental Research Laboratory of the U.S. Environmental Protection
Agency. This work is part of the program, Measurements of
High-Temperature, High-Pressure Processes (Contract 68-02-2153), intended
to produce the new sampling technology needed for advanced coal
conversion processes. The EPA project officer was William B. Kuykendal.
An overview of the results of both sampling operations is
presented in Section 2. Section 3 discusses the sampling system
equipment in detail and gives a brief description of the Exxon Miniplant
test facility. Section 4 describes assembly and operating procedures and
contains a narrative of events in each phase of tests. All results and
supporting data are presented in Section 5 while Section 6 summarizes the
program conclusions.
-------
SECTION 2
OVERVIEW OF RESULTS
This Section presents an overview of the results from both series
of sampling operations, including the Phase I demonstration tests and the
Phase II condensation tests. A more thorough discussion of the results
can be found in Section 5.
2.1 PHASE I — DEMONSTRATION TESTS
The objective of the first sampling operation was to demonstrate
the HTHP sampling system's range of capabilities. Three sampling runs
were successfully made: one using a filter* to collect total
particulate, and two using a cascade impactor to collect particle sizing
data. Trace metals and trace organics sampling equipment was operated
during the filter run. The tests produced the following data:
• Particulate concentration
• Particulate size distribution
t Moisture content
• Particulate chemical composition
• Particulate shape
*A complete detailed description of the sampling equipment'is given in
Section 3.
-------
• Duct gas temperature and pressure
• Access port and valve external surface temperatures
The test also produced samples of trace organics collected on XAD-2
porous polymer sorbent and trace elements collected in oxidizing impinger
solutions. However, the analysis of these samples is beyond the scope of
the HTHP program.
The test series demonstrated the capability of the sampling system
to operate in a severe PFBC environment of 740°C (1360°F) and 910 kPa
(9 atm). Generally, the system operated as designed with regard to:
obtaining access to the pressurized duct while the process was operating,
inserting the sampling probe, sampling the gas stream, and withdrawing
the sampling probe. However, as might be expected in a first field test
demonstration, a few hardware problems were found. Most of these were
corrected before the sampling tests, but one uncorrected problem, a
malfunctioning impactor heater, gave sample collection temperatures which
were lower than desired. The heater was replaced for the second phase of
testing.
During the test sequence, the sampling operations proceeded very
smoothly. The three sampling runs were completed within a 30-hour period
(20 working hours). The tests showed the versatility of the system,
operating with two different types of particle collectors, with and
without trace element sampling equipment.
2.2 PHASE II — CONDENSATION TESTS
The goal of Phase II was to determine the effect of sample cooling
on measured particlate mass and composition. We were particularly
concerned that trace elements might condense in the probe in significant
quantities between process temperature and 450°F. The condensation
-------
effects tests were also successfully performed. A total of four separate
runs were completed with the cyclone-dual filter configuration. The only
difference between the runs was the sampling time of each, and, in the
case of test number three and four, two Saffil alumina filters were
"sandwiched" to comprise the front filter (at stream conditions). Tests
1 and 2 used a single front filter. All other conditions, both in the
FBC system and in the sampling system remained, nominally, the same.
Trace element and trace organic sampling equipment were not employed in
the Phase II tests.
Again, as in the first test series at the Miniplant, certain
hardware problems prevented some measurements, the most important of
which, was the malfunctioning of the stack thermocouple. This
temperature is approximated at 730°C (1350°F), the average stack
temperature during the first test series. Very similar PFBC system
operating conditions between the two test series make this a reasonable
approximation. Another less critical malfunction occurred in the
transport tube outlet filter thermocouple. This problem was an
intermittent electrical short. Consequently, the measurement could be
made only periodically. Another problem occurred with the scalping
cyclone. Its protective gold plating blistered and peeled causing gold
contamination in the cyclone and front filter catches. The resultant
oxidation of the titanium cyclone body did not appear to contribute to
the contamination problem.
As previously mentioned, the purpose of the Phase II tests was to
investigate the effect of sample cooling on measured particulate mass and
composition. Based on one test at one set of PFBC operating conditions,
the Phase II tests showed no apparent indication of trace element
-------
condensation at the reduced sample collection temperature. In other
terms, we can say that sample cooling seems to have had little effect on
measured particulate mass and composition.
-------
SECTION 3
EQUIPMENT DESCRIPTION
The following discussion is divided into two parts: (1) a
description of the advanced sampling system, this section being further
divided to discuss the original probe configuration and the modified
configuration for the condensation effects tests, and (2) a description
of the PFBC Miniplant test facility.
3.1 SAMPLING SYSTEM
The sampling system described in this report samples particulate,
trace organics and trace metal contaminants in high-pressure, high-
temperature gas streams. The system represents an advancement in the
state of the art designed to sample new coal conversion processes. This
section is divided into a discussion of the sampling as it was used both
in Phase I and Phase II tests. Since there were many similarities
between the two systems, such as the pressure containment vessel and
traversing mechanism, only the differences between the two probe
configurations will be mentioned in Section 3.1.2.
3.1.1 Phase I -- Demonstration Tests
The basic functions of the sampling system are to:
• Safely contain facility pressure
• Insert the sample probe into the process duct while the
process is operating
• Extract a representative sample
-------
• Cool the sample to a temperature which is compatible with
developed particle collectors yet prevents condensation
(230°C)
t Collect and aerodynamically size particulates
• Collect trace organics and trace metals
• Monitor duct conditions and control sample flowrate to give
accurate isokinetic capture conditions
• Remove the sample probe and close off duct access so that
collected samples may be removed while the process remains
pressurized
To perform these functions, the sampling system includes the
following subsystems:
• Sample probe assembly
t Dowtherm coolant system
• Hydraulics for probe traverse actuation
• Flow control oven
• Trace organics module
• Trace metal impinger train
• Control consoles
System capabilities are described in Table 3-1. Figures 3-1 and
3-2 show system schematics of the HTHP sampler.
3.1.1.1 Probe Assembly
The probe assembly includes the sample probe, probe housings, and
duct access valves. The sample probe itself, shown in Figure 3-3, con-
sists of the sample nozzle, pitot tube, Dowtherm-cooled section with man-
ifold, a sample particulate collection device, a flowmeter, a heated
transport tube section, transducer and control devices mounted on the
8
-------
TABLE 3-1. SAMPLING SYSTEM CAPABILITIES
Sample Environment
t Temperature
• Pressure
Gas Constituency
CO
C02
NO
S02
H20
NOX
H2S
trace orgam'cs
trace inorganics
Stream Velocity
Particulate Grain Loadings
• Particulate Size Range
(for classification)
• Duct Size
Sampling System Configuration
Traverse Capability or Penetration
of Nozzle into Duct or Vessel
650°C - 1000°C (1200°F - 1800°F)
300 - 2000 kPa (3 - 20 atm)
Concentrations subject to further
investigation, dependent on process
sampled
2-46 m/s (8 - 150 fps)
0 - 34.3 g/m3 (0-15 gr/ft3)
(subject to further consideration
and actual process characteristics)
0.2-26 microns (Notes: Larger
particulates may be acceptable in
most cases of total mass determination.
or if classified, they may be amenable
to "scalping" ahead of classification
device)
Variable depending on probe; std.
is 20.3 cm (8 in.) I.D. minimum
Modular, so as to allow in-situ or
extractive sampling by cooled probe
Approximately 46 cm (18 in.) either
in-situ or extractive configuration
(some dependence on internal config-
uration of duct or vessel). Can be
extended by relatively minor hardware
modification (longer probe, chamber
extension, spool piece, etc.)
-------
TABLE 3-1. (Concluded)
Access Process Port Requirements
Stream Constituency Analysis
Standard: 10.2 cm (4 In.) IPS
minimum, 136 kg (300 lb.) flange
access through 10.2 cm (4 In.)
IPS alloy gate value (Note:
Smaller ports may be acceptable
If special probe assembly is used)
Particulates, gases (inorganic and
organic, trace elements, trace
organics)
10
-------
S-038b
Probe Drive
Hydraulic Cylinder
Microswitches For
Transverse Control
Inner Tubular Housing
Hydraulic Lines
Control Umbilical
Dowtherm Coolant
Systems And Controls
JL
Outer Tubular
Housing
Dowtherm Coolant
Supply And Return
=_^_^._=_=^===,-^-^ /
Sample Line
B T) H a
a 3 ra§
3* ® -s S
•aa* Hts'4
-»' A IV
Hydraulic
Control Valve
And Operator
Control Console Supply System
Figure 3-1. High-temperature, high-pressure sampling system.
ACUREX
-------
i
Flow
Process Duct
Access Valves
Enclosure
(Pressure Boundary)
s
KNKNL/
Control Valves
Flexible Line
Heat Tracing
Vent
Flow Organic
Controls Collector
Figure 3-2. System schematic.
Trace
Metals
Impingers
-------
Transducers
& controls
Impactor
stacks
Heated
transport
tube
5
i
Nozzles
Figure 3-3.
Exploded view of HTHP probe.
Pi tot
tube
15
-------
end of the probe. All probe components, internal and external, that
would be exposed to temperatures in excess of 1000°F, were constructed
of 625 Inconel. These include the probe tip, nozzle, cooling section,
and transport tube up to the cascade impactor. Most other probe
components were constructed of grade 316 stainless steel. The assembled
sample probe is then installed in an inner probe housing. The inner
probe housing is a tube that telescopes into an outer probe housing and
is sealed by a bolted flange and sliding seal. The outer probe housing,
on its laboratory support stand designed to a factor of safety of 4.0, is
shown in Figure 3-4. The outer probe housing is bolted to the process
duct by two 10.2 cm (4-in) diameter gate valves in series. This 10.2 cm
(4-in) opening provides clearance for the sample probe to be inserted
into the sample stream, as shown in Figure 3-5. The entire telescoping
system, shown in Figures 3-6 and 3-7, is driven by hydraulic cylinders.
Two types of sample particulate collection devices were used in
the demonstration tests. They were a University of Washington Mark III
cascade impactor with seven stages of particulate sizing and a glass
fiber thimble filter with a large total mass capacity but with no sizing
capability.
The inlet nozzle is interchangeable to allow isokinetic sampling.
The nozzle diameter used was 1.9 cm (0.75 in) for all tests and was sized
according to the anticipated Exxon miniplant stream conditions. The
actual stream velocity (a calculated, not measured value) was not as
close to expected conditions as would be desirable. A discussion of
isokinetic sampling rates is in Section 5.
17
-------
Figure 3-4.
Aerotherm HTHP sampling probe and duct interface valve.
-------
I- •
eo
in
o
Figure 3-5.
Access valves.
-------
ro
CO
SEE SEPARATE PARTS LIST PL 7123-053
1 23
Figure 3-6. HTHP probe housing/side view.
-------
Figure 3-7. HTHP probe housing/end view.
-------
ro
en
Figure 3-8. HTHP probe/side view/front half.
-------
Sample gas enters the inlet nozzle isokinetically and travels
through the Dowtherm-cooled section, shown in Figure 3-8. The sample gas
then passes through one of the particulate collection devices mentioned
above. It then goes to a flowmeter and an electrically heated and
controlled transport tube section which is mounted to and routed through
a rear access plate. Process pressure, velocity pressure, orifice
differential pressure, and sample gas temperature instrumentation lines,
lead aft to the access plate, as shown in Figures 3-8 and 3-9.
Thermocouples, pressure transducers, control valves, and Dowtherm
manifolds are mounted behind the rear access plate (Figures 3-10 and
3-11). After cooling, the sample gas, now at 232°C (450°F), is
transported through a heat-traced line to the flow control oven.
3.1.1.2 Dowtherm Coolant System
The sample conditioning heater/cooler in the front probe assembly
receives working fluid from the Dowtherm system, shown in Figures 3-12
and 3-13. This system maintains the Dowtherm temperature at about
232°C (450°F). The system consists of a pump, heater, heat
exchanger, flowmeter, transfer lines, and a primary receiver/deareator
tank with a Dowtherm surge/supply tank and an air receiver tank.
Dowtherm can be quickly heated or cooled by selected valving
arrangements. The pressure can be controlled to raise the boiling
point. Heat flux can be controlled with a flowmeter. The self-contained
unit also has mechanical instrumentation for flowrate, system pressure,
temperature, and fluid level for process monitoring.
3.1.1.3 Hydraulics
Probe insertion, extraction, and precise positioning is
accomplished by hydraulic cylinders. These drive the telescoping probe
26
-------
M M "-ACCEPTABLE ROUTING
SELTION ?i-n LOCATION FOR HEATER
2 PLACED ACCEPTABLE ROUTING
" LOCATION FOR THERMOCOUPLE
, REF
Figure 3-9. HTHP probe/side view/back half.
-------
D 50726 7123-053 A
Figure 3-10. HTHP probe rear access plate and controls/side and end view.
-------
SEE SHEET I FOR REVISIONS
36) LOCATE AT ASSf
50726
7l23r053
Figure 3-11. HTHP probe rear access plate and controls/top view.
-------
GO
o
aur
outlet
temperature
OmercutUi
pressure gtuge
System outlet
temp
Fran HTHP
probe
outlet
Heat
exchanger
Figure 3-12. Dowtherm system.
-------
Figure 3-13. Dowtherm console.
31
-------
housing, which, in turn, is driven by a hydraulic pump powered by an
electric motor. Solenoid valves plumbed in line with the hydraulic
supply lines are used to control the hydraulic cylinders. These operate
by remote switches on the probe control console. Fail-safe devices .have
also been incorporated to avoid inadvertantly traversing the probe.
Probe positioning in the process duct can be automatically repeated by
setting cams prior to testing.
3.1.1.4 Flow Control Oven
Sample gas at duct pressure exits the throttling valve of the
probe and enters the flow control oven. This oven contains a back
pressure regulator to reduce sample gas pressure to 172 kPa (25 psig), an
adjustable-choked orifice for flow measurement, a heater, and a flow
control valve, as shown in Figures 3-14 and 3-15. Excess sample gas is
vented to the atmosphere. The balance is routed to the impingers and
organic train at a known pressure, flowrate, and temperature. The oven
was run at 232°C (450°F) for this series of tests to avoid
condensation of selected sample gas constituents. Controls and
instrumentation are remotely mounted in the gas train control console
which is connected by an umbilical cord containing the various pressure,
power, and temperature lines.
3.1.1.5 Organic Module
An organic module was used to collect trace organic gas
constituents. It cools the sample gas to 20°C (68°F) and collects
organic vapors in a porous polymer granular sorbent bed. Rohm-Haas XAD-2
chromatographic packing material -- chemically cleaned prior to testing
~ was the sorbent used. Cooling and conditioning is accomplished by a
single and double concentric shell heat exchanger, and by water
33
-------
To
Back pressure relief
To ATM
To organic tr«1n
•nd linger bottles
Over prtisure
rupture disk
Insulated httt
traced staple
line
Gas saeple
fran HTHP
probe
Indicating heat
trace temperature
controller
Differential
pressure
gauge
.r*in w^
control console I
Figure 3-14. Gas sampler train —flow control oven.
-------
CO
en
3,4,. ,/2,QDX .04-9
MA_E CDsJKtECLTCR
CONNE.CToa
STA^4DARD CVCLQNJE, CVEN t
"'° ^ff ^
'"'." -' '".- .-L5S1JS
&CUREX
' Aerolhem
D 50726 7237-OOe
Figure 3-15. Oven assembly.
-------
circulating through the impinger ice bath. The water is either heated or
cooled automatically to the preset system temperature. Condensation is
expected to occur and a valve is available for decanting the sample.
This unit is identical to that used in the Acurex commercially available
Source Assessment Sampling System. The organic cartridge and the organic
module assembly are shown in Figures 3-16, 3-17, and 3-18 respectively.
3.1.1.6 Trace Metal Collectors
A train with three high-volume glass impingers followed by a
silica gel dryer was used to collect trace metals. The impingers were
charged with the following oxidizing reagents as prescribed by the
IERL-RTP Procedures Level 1 Environmental Assessment Manual (Reference 1)
Impinger Solution
No. 1 6M - H202
No. 2 0.2 M (NH4)2 S208 + 0.02 M AgN03
No. 3 0.2 M (NH4)2 S208 + 0.02 M AgN03
No. 4 Indicating Type Silica Gel
Figure 3-19 is a photograph of the trace element impingers along with the
organic module and flow control oven as they appear assembled for a test
run. Figure 3-20 shows a schematic of the organic module and impinger
bottle assembly.
3.1.1.7 Controls
The sampling system includes instruments for measuring
temperatures and pressures in the process duct, the gas sample, system
heaters and coolant. The system has controls for sample flowrate,
traverse drive, heaters, coolant pump and purge gas. Sample flowrate was
controlled by a motor-actuated valve located at the probe exit. A
36
-------
80 MESH 316SS
UPPER CRIMP RING
AND SEALING FLANGE
316SS TUBE
LOWER CRIMP RING
Figure 3-16. Organic cartridge.
-------
oo
CXI
Return Flow
Impinger Bath
Cold Water From
Impinger Bath
Hot Gas
From Oven
Liquid Passage
Gas Passage
Gas Cooler
Organic Cartridge
Condensate
Reservoir
Section
3-Way Solenoid Valve
To Heat Exchanger
In Impinger Case
From Heat Exchanger
In Impfnger Case
Cooling Fluid
Reservoir
Immersion
Heater
Liquid Pump
Temperature
Controller
Figure 3-17. Organic module.
-------
Ice Water In
Hot Gas In
I I
Ice Water Return
Gas Cooler
Inner Wall
Coolant Fluid Out
Coolant Fluid In
Organic Cartridge
• Case
Cool Gas Out
Condensate Out
Figure 3-18. Organic module —exploded view.
39
-------
Flow
Control
Oven
rganic
odule
Figure 3-19. Flow control oven and gas train.
-------
From gas sample
train-flow control
Primary concentric
double-shell heat
exchanger
Secondary
concentric
single shell
heat exchanger
CO
3-way
solenoid
valve
Hater cooling lines
1
.
>
>
>
r
t
Imners
heater
7
Ion
In
te
CO
dlcatlng
mperature
ntrol ler
<^>
Accumulating
(cooling
reservoir)
To ATM
0
s
•S
Cr
Bottle No. 4
silica gel
Bottle No, 1 t No. 2
silver nitrate &
ammonium persutfate
Bottle
silica
No.
gel
3 \ ^F
Ice bath
coolant
pump
Figure 3-20. Organic module and impinger bottles.
-------
redundant manual valve preceeded the automatic valve for safety
purposes. The probe traverse drive was hydraulically actuated from a
control console. All heaters were thermoscatically controlled. The
coolant pump was manually operated by a switch located on the Dowtherm
console. The nitrogen purge gas was supplied by Exxon and controlled by
a single stage regulator mounted adjacent to the probe housing. Most of
the instrument readouts and controls are housed in the two portable
control consoles, shown in Figure 3-21. Control, power and instrument
connections are made by multi-pin connectors and umbilical cords.
3.1.2 Phase II — Condensation Tests
Following the system demonstration tests, a second series of sam-
pling operations was conducted at the Exxon Miniplant. The purpose of
these tests was to investigate the effect of sample cooling on measured
particulate mass and composition. There was specific concern that trace
elements in vapor form might condense to the solid state between process
temperature and pressure conditions and the particulate collection
temperature and pressure.
Of particular interest to process developers are the more common
corrosive alkali metals, sodium and potassium. For these tests, the
sampler was configured to collect particulate at process temperature (see
Figure 3-22), so trace element condensation occurring within the sampling
system could be investigated. First, particulate would be filtered at
process conditions, then the sample could be cooled and filtered to
collect condensation products. The trace element concentrations could be
analyzed and compared for significant differences between the hot and
cold filters.
44
-------
en
Figure 3-21. Control consoles,
Control consoles.
-------
Normal
Cooler
Impactor
Process Flow
Condensation Test
Scalping 732° C
Cyclone Filter
Sample Flow
Process Flow
(Or Filter) Throttling
Valve
Control
Valve
Choked
Orifices
I
1
Cooler
^
!
(400°F)
Filter
Figure 3-22. Probe configurations.
-------
The individual components of this sampling train, where different
from the standard configuration, are discussed in the following
sections. It should be noted that since this test series was to study
condensation phenomena only, no provisions for sampling trace organics or
trace elements by the impinger method were included. After final
filtering through the cold filter, the sample gas was simply vented to
the atmosphere.
3.1.2.1 Scalping Cyclone
The cyclone (shown in Figure 3-23 and 3-24) at the front of the
probe was designed and fabricated by Southern Research Institute to
operate at stream ccnditions. It was made of 6AL-4V titanium alloy with
a 26-ym thick gold plate for corrosion resistance. Because of the high
temperature, it was designed with flat faced flanges and bolted with ti-
tanium nuts and bolts.
The cyclone's nominal D5Q cutpoint is 0.3 urn (aerodynamic
diameter) at 4.38 x 10"5 m3/sec (1.01CFM) at standard temperature and
pressure. SRI was unable to predict the DSQ cutpoint at stream
temperature and pressure.
3.1.2.2 Front-End Filter (Saffil Alumina)
The front end filter element is made from Saffil alumina fiber
matt. Saffil alumina is a ceramic fiber material that Acurex is
currently testing for high-temperature baghouse filters. This material
seems to offer excellent temperature resistance and effective filtration,
but its performance has not yet been fully characterized. Its
performance in the condensation tests (Phase II) was quite good,
particularly with a two-filter "sandwich". The filter matt is sandwiched
between two 47-mm 316 SST screens stitched together with 316 SST wire.
48
-------
Figure 3-23. Scalping cyclone assembled.
-------
T
1.905 cm
(0.7
75 in
0.508 cm
(0.2 in)
0:836 cm
(0.329 in)
1.524 cm
(0.6 in)
0.9525 cm
(3/8 in)
Figure 3-24. Scalping cyclone disassembled.
50
-------
The filter housing is made from 316 SST and uses flat face bolted flanges
for sealing.
3.1.2.3 Sample Conditioning
The primary requirement of the sample conditioning system is to
reduce the temperature and pressure to 204°C (400°F) and 101 kPa
(1 atm). A further requirement of the system is to not let the
temperature drop significantly below 204°C (400°F).
To accomplish this, the sample undergoes the following process:
• Cooling from stream conditions to 232°C (450°F) in the
existing Dowtherm cooling section
• Transport through a bypass sleeve in the impactor housing
section because it is important to keep the velocity high to
keep any condensates from settling
• Reheat to approximately 300°C (570°F). This is necessary
because sonic throttling (done in the next section) will cool
the gas about 80°C (170°F) at the throat (the temperature
will then recover back to 300°C (510°F)). Heating is done
by running the gas through an annular passage past electrical
heaters, as shown in Figure 3-25. The gas is passed through
the annular passage because a high velocity is required to get
the necessary heat transfer coefficient.
• Pressure drop from stream pressure to ambient occurs through
three critical orifices. This is done to avoid supersonic
conditions downstream of each throat and hence very large
local temperature drops. The orifices were sized such that
the velocity downstream of each throat was slightly supersonic
at the design flowrate.
51
-------
xxx x x x x" x x" x*
tn
ro
Flow measurement
orifice
Sonic orifices
Figure 3-25. Transport tube.
-------
• Cooling from 300°C (570°F) to 204°C (400°C). This is
done between the exit of the probe and the rear-end filter
housing through natural air convection. The tube is heat
traced to give a final temperature control.
3.1.2.4 Final Filter Gelman Micro-Quartz Glass Fiber
The final cleanup filter was a 47-mm Gelman microquartz glass
fiber filter. It has a minimum 99.9-percent retention of 0.3 m
particles. It was selected because of its low trace metal content.
3.2 EXXON MINIPLANT TEST FACILITY
This section describes the Exxon Miniplant facility itself and the
deployment of the sampling system in the facility during both series of
sampling operations.
The Miniplant is a pilot-scale pressurized, fluidized bed
combustor operated by the Exxon Research and Engineering Company at
Linden, New Jersey. The PFBC process is being developed as a more
efficient and cleaner method of burning coal. A sketch of a typical PFBC
system is shown in Figure 3-26. Coal, along with limestone or dolomite,
which act as SO^ sorbents, is injected into the bottom of the
pressurized boiler. Coal is burned in the limestone bed which is
fluidized by the incoming combustion air. Sulphur dioxide formed in the
combustion process is removed by the limestone bed. Steam coils immersed
in the fluidized bed remove some of the heat of combustion and maintain
the bed temperature in the range of 816°C (1500°F) to 927°C
(1700°F). Steam thus generated operates a steam turbine. The
desulphurized flue gas passes through a particulate removal system and is
then expanded across a gas turbine. The particulate removal system must
reduce the particulate loading down to levels sufficiently low to protect
53
-------
Gas turbine
Sampling location
Separator
Jl
Coal and'
make-up
sorbent
Air
compressor
Boiler
Solids
transfer
system
£
X.
r
To sulfur
recovery
I Separator
I
fl
Discard
Regenerator
Figure 3-26. Pressurized fluidlzed bed coal combustor system.
54
-------
the gas turbine and meet current pollutant emission standards. The
Miniplant facility does not presently include a final gas cleanup device
or turbines.
The Miniplant facility consists of the combustor tower and control
building. The combustor is a four-story structure, with platforms at
each level. Stairways connect the platforms. A crane on the top level
is available for moving large equipment. The control building includes a
laboratory area.
For both test phases, the sampling location was downstream of the
secondary cyclone (particulate removal device), as indicated in Figure
3-26. At this location, there is a specially constructed duct section
with a sampling port. The sampling port has a 10.2-cm (4-inch) 136-Kg
(300-pound) pipe flange which interfaces with the sampling system access
valves. The duct diameter at the sampling location is 25.4 cm (10
inches).
The sampling location was physically located at the top of the
combustor tower. When installed, the probe assembly was horizontal,
about 1.22 m (4 feet) above the platform (see Figure 3-27). The coolant,
console and hydraulic pump were also placed on the top platform, near the
probe assembly. The control consoles and gas train equipment were set up
one floor below, where a partial enclosure gave some weather protection.
The route between the laboratory area and the sampling location
included four flights of stairs and about a 30.5 m (100-feet) walk. The
sample probe assembly was hand-carried along this route before and after
each sampling run. Probe cleaning, assembly, disassembly and sample
removal were all done in the laboratory. The lab facility had an
analytical balance, oven, desiccator and other equipment used in sampler
55
-------
Figure 3-27
HTHP probe assembly
installed at Exxon miniplant.
-------
preparation and sample processing. Labware and materials were supplied
by Acurex.
The Exxon facility provided a number of utilities supporting the
sampler operation. Power connections, water, and nitrogen supplies are
summarized in Table 3-2. In addition, Exxon supplied technician support
during equipment setup and disassembly.
TABLE 3-2. UTILITY REQUIREMENTS
Electrical:
480 VAC, 3 phase, 40 amp
115 VAC, 15 amp
Water:
18.9 L/min (5 gpm), 34.47 kPa (50 psi)
Pure Nitrogen:
(flow and pressure required depending on stream
conditions)
• For this test, about 8.76 x lO"1* Nm3/sec.
(2 scfm) at 861.8 kPa (125 psi)
1 line
6 lines
1 line
1 line
59
-------
SECTION 4
TEST DESCRIPTION
This section describes assembly and operating procedures for the
sampling equipment and some of the significant events which occurred
during the two test phases. The narrative of events in each phase is
divided into four sections: procedures, pretest activities, sampling
runs, and post-test activities.
4.1 PHASE I -- DEMONSTRATION TESTS
4.1.1 Procedures
Equipment setup and operation was done according to a formal
procedure which defined proper installation of access valves and probe
housing, probe setup and assembly, system preparations for testing, test
sequence, shutdown and sample removal.
In several cases, decisions were made in the field to change
predefined procedures. For example, the exposure and limited space on
the sampling platform made impactor removal at the sampling location
impractical. The entire probe was carried to the lab for disassembly.
In precleaning the sampling equipment, the procedures in the
IERL-RTP Procedures Manual for Level 1 Environmental Assessment were
followed with one exception; the nitric acid passivation of some internal
surfaces of the probe, organic module and flow control oven was omitted
60
-------
because large acid containers were not available. Sample removal and
post-test cleaning also followed Level 1 procedures.
4.1.2 Pretest Activities
Pretest activities included planned unpacking, setup and checkout,
plus fixing several problems with the facility and sampling system. The
test preparations were completed between March 22 and March 30.
Heavy equipment was installed with the help of Exxon personnel. For the
nitrogen purge gas, Exxon provided a connection to the facility nitrogen
supply. Exxon also assisted in making a support for the cantilevered
probe housing.
4.1.3 First Run
For the first test run, the sampling system was set up using the
thimble filter particulate collector and gas train equipment for the
purposes of obtaining grain loadings. Following preheating, the duct
access valves were opened and the sampling probe inserted into the duct
stream. The sample flow control valve was opened until the flow orifice
indicated a sample flow of 0.75 acfm at nominal particulate collector
conditions. When flow conditions were established, the gas train flow
control valve was opened, diverting total sample flow through the organic
module and impinger train. Sampling continued for 30 minutes.
Instrument readings during the test run are listed in Table 5-2. At the
end of the test run, the motor driven sample flow valve was left open and
the sample flow was shut off using the manual ball valve. The probe was
then withdrawn and gate valves were closed. After cooldown, the probe
assembly was removed. The probe and gas train were taken to the lab area
for sample recovery and cleaning.
61
-------
4.1.4 Second Run
For the second test run, the cascade impactor was used for
participate collection. Since this was to be a very short test with a
small amount of gas sample collected, the gas train equipment was not
used. Based on estimated particle concentration and impactor capacity,
the maximum sampling duration was estimated to be between 30 seconds and
1 minute. For this test run, 30 seconds was chosen. To achieve proper
sample flow as soon as possible, the motor driven control valve was left
at the same setting as the earlier filter run, and on-off control
accomplished with the manual ball valve. As soon as the probe reached
the in-stream position, the sample flow was started. No attempt was made
to adjust flow while sampling. After 30 seconds, sample flow was stopped
with the ball valve, the probe was withdrawn and access valves closed.
After cooldown and probe removal, the probe assembly was carried as
carefully as possible down the combustor tower stairs to the lab. There,
the impactor assembly was removed, disassembled and inspected. The
amount and patterns of the catch seemed to indicate normal operation of
the device (see Figures 5-3). However, on one stage (Stage 4) the
substrate shifted slightly, and on another (Stage 7} some of the jets
were plugged. After sample removal and cleaning, the probe was ready to
be set up for the third and final test run.
4.1.5 Third Run
The third test run also used the impactor for particulate
collection and omitted the gas train equipment. Based on the lightly
loaded appearance of the 30-second impactor catch from Run No. 2, the
duration of this run was increased to 1 minute. The flow control method
for this run was identical to Run No. 2. The manual valve was again used
62
-------
to start and stop sample flow with no attempt to adjust flowrate during
sampling. Again the probe was taken to the lab for disassembly and
sample removal. The impactor substrates were noticeably more heavily
loaded than for the 30-second impactor run (see Figures 5-3 and 5-4).
Figures 5-3 and 5-4 also show that the substrates from Stage 7 were
partially plugged for these runs. We were unable to clear the jets
without risking alteration of the jet diameter. With the completion of
sample removal and cleaning of the sampling equipment, the testing phase
was finished.
4.1.6 Post-Test Activities
Following test completion, sampling system hardware was packed and
stored onsite at Exxon in preparation for the Phase II sampling program.
Test samples were brought back to Acurex, where analysis was performed.
4.2 PHASE II - CONDENSATION TESTS
4.2.1 Procedures
Equipment setup and operation was executed according to an amended
formal procedure which was developed from the previous demonstration
tests. This defined a proper sequence of assembly of the gate valves,
probe housing, ancillary equipment and prescribed probe setup, systems
preparations for testing, test sequence, shutdown and sample removal.
As in the previous demonstration tests, all procedures followed
the IERL-RTP Procedures Manual for Level 1 Environmental Assessment.
4.2.2 Pretest Activities
Pretest activities consisted of unpacking the probe from Exxon,
storage, setup and checkout, and check fitting the modified probe parts.
Test preparations were completed between May 21 and May 22. Exxon
personnel assisted in the installation of heavy equipment and utilities
63
-------
supply. The previous nitrogen purge gas, probe housing support, and
cooling water lines were used.
The front cyclone and filter housing, choked orifice train,
extension tube and rear filter housing were fitted to the outer probe
housing for check fitting and traversed through the operating modes.
During the first traverse through the access valves, the front cyclone
and filter failed to clear the sampling valve seats resulting in a damage
to the cyclone nozzle and filter housing. A redesigned filter housing
which featured a reduced profile and an integrated filter screen was
machined on May 23 with the assistance of Exxon personnel. The assembly
was retested May 25 with success.
4.2.3 Runs 1 and 2
For the first test run, the choked orifice train was not used due
to an installation problem involving 0-ring seal abrasion. Instead, the
o
primary flow control valve was set to the desired flow of 0.0144 m /min
using the previous demonstration test data results. Following the
prescribed preheating, the duct access valves were opened and the sampling
probe inserted into the duct stream. The manual ball valve was opened
and the flow measured by the existing orifice within the inner probe.
Sampling continued for 30 minutes with data taken at 5-minute intervals.
The manual ball valve was closed with the flow control valve left in its
initial position. The probe was then withdrawn and gate valves closed.
The system was then cooled and the probe assembly removed and taken to
the lab area for sample recovery and cleaning. During sample recovery,
it was noted that the front filter had evidence of particulate blowby.
Cleaning solvent rinses were bottled and labeled for analysis.
64
-------
For the second test run, the choked orifice train was installed by
modifying mechanical links for more clearance within the existing
transport tube. To prevent mechanical abrasion of the 0-ring seals, a
rinse solvent mixture was used as a final rinse and lubricant. Both test
runs were conducted May 23.
4.2.4 Runs 3 and 4
For Test Runs 3 and 4, the choked orifice train, extension tube,
front and rear filters, and the cyclone were used following the identical
procedures and test parameters as Run 2. Two saffil alumina filters were
"sandwiched" to comprise the front filter in order to minimize
particulate blowby. Sample recovery showed little or no sign of
particulate blowby on these runs. However, chemical analysis of the
cyclone and front filter catch showed significant gold contamination.
This was caused by failure of the cyclone's protective gold plating upon
extended exposure to the PFBC flue gases. Titanium contamination due to
heavy oxidation of the cyclone body was not evident in any of the
samples. With the completion of sample recovery and cleaning, the
testing phase was finished.
4.2.5 Post-Test Activities
The sampling system hardware was packed for surface shipment back
to Acurex. Solvent wash test samples were sent by special surface
carrier and test filters were hand-carried back to Mountain View.
Packing and packaging were completed May 24.
65
-------
SECTION 5
DATA AND RESULTS
This section presents the detailed information collected and the
results obtained during the complete HTHP sampling system test program at
Exxon's Miniplant. This section has been divided into subsections which
discuss the individual data and results from each of the two test series,
the Phase I ~ Demonstration Tests and the Phase II ~ Condensation
Effects Tests. The Phase II discussion also includes a discussion on the
comparative results of both phases of testing.
5.1 PHASE I ~ DEMONSTRATION TEST DATA
5.1.1 Test Conditions
Plant operating conditions are listed in Table 5-1. The nominal
conditions were identical for all three sampling runs. The facility ran
steadily without interruption during the tests.
5.1.2 Instrument Readings
The sampling system includes a number of instruments which measure
duct, sample and equipment operating conditions. Readings from these
instruments are presented in Tables 5-2, 5-3 and 5-4.
Table 5-2 gives readings from probe assembly instruments. Duct
temperature and pressure were typically about 740°C (1360°F) and 860
kPa (110 psig). The drop in temperature from 900°C (1650°F) in the
combustor to 740°C (1360°F) at the sampling location is due to normal
66
-------
TABLE 5-1. TEST CONDITIONS
Run:
#2
Date
Time
Ambient temperature
Bed Conditions
Temperature
Pressure (gage)
Ca/Sulphur Ratio
Excess Air
Coal
Dolomite
Flowrate - sm /m1n (scfm)
Average Duct Velocity -
m/s( ft/sec)
3-31-77
3:30 p.m.
18°C (64°F)
900°C (1650°F)
912 kPa (9 atm)
1.25
30%
Champion
Pfzizer
14(544)
2.0(6.7)
4-1-77
10:30 a.m.
21°C (70°F)
900°C (1650°F)
912 kPa (9 atm)
1.25
30%
Champion
Pfzizer
14(546)
1.9(6.3)
4-1-77
2:40 p.m.
19°C (67°F)
900°C (1650°F)
912 kPa (9 atm)
1.25
30%
Champion
Pfzizer
14(546)
2.0(6.7)
CT>
-------
TABLE 5-2. PHASE I PROBE INSTRUMENTATION READINGS
Run No. 1
Insertion
Sample Flow
Shut-off
Run No. 2
Before Insert
Sample Flow
Run No. 3
Insertion
Sample Flow
Time
3:10 p.m.
3:22 p.m.
3:32 p.m.
3:35 p.m.
10:30 a.m.
2:58 p.m.
Elapsed
Time
(minutes)
0
0
0
0.1
5.0
10.0
15.0
20.0
25.0
30.0
0
0.5
0
0
0
0.33
0.67
0.83
1.0
Stack
Pressure
(pslg)
861.8(125)'
861.8(125)"
758.4(110)
751.5(109)
758.4(110)
758.4(110)
751.5(109)
758.4(110)
758.4(110)
758.4(110)
834.3(121)"
827.4(120)
861.8(125)a
765.3(111)
Stack
Gas
Temp
°C(°F)
77(170)
83(190)
738(1360)
732(1350)
732(1350)
727(1340)
716(1320)
716(1320)
716(1320)
716(1320)
91(195)
738(1360)
88(190)
738(1360)
738(1360)
738(1360)
738(1360)
738(1360)
738(1360)
Dowtherm
Inlet
Temp
•C(°F)
222(431)
218(425)
225(437)
225(437)
225(437)
225(437)
225(437)
218(425)
225(437)
225(437)
222(431)
222(431)
222(431)
Dowtherm
Exit
Temp
°C(°F)
216(420)
208(407)
224(435)
224(435)
224(435)
224(435)
224(435)
208(407)
224(435)
224(435)
216(420)
216(420)
216(420)
Sample
Temp
Impactor
Inlet
°C(°F)
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Sample
Temp
Orifice
Inlet
°C(°F)
161(322)
167(332)
167(332)
178(352)
189(373)
202(395)
210(410)
216(421)
227(441)
237(459)
167(332)
107(225)
164(327)
164(327)
Sample
Temp
Transport
Tube Exit
•CPF)
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Sample
Flow-
rate
m'/sec » 10'"
(acfm)6
0(0)
0(0)
0(0)
3.45(.73)
3.02(.64)
3.87(.82)
3.92(183)
4.0K.8S)
4.11(.87)
4.15(.88)
0(0)
4.25(.90)
0(0)
0(0)
0(0)
4.29(.91)
4.20(.89)
4.15(.88)
Impactor
Heater
Temp
•CCF)
.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Transport
Tube
Heater
Temp
'C('f)
232(450)
233(452)
233(452)
233(452)
233(452)
233(452)
229(445)
238(460)
238(460)
238(460)
229(445)
229(445)
229(445)
CT>
oo
-------
TABLE 5-3. GAS TRAIN INSTRUMENT READINGS
MO
Run No. 1
Start Flow
Stop Flow
Time
3:10 p.m.
3:22 p.n.
3:32 p.m.
Elapsed
Tine
0
0
0
0
5.0
10.0
15.0
20.0
25.0
27.65
Flow-
rate
a'/sec x 10"*
(acf«)
4.72(1.0)*
0(0)
0(0)
0{0)
3.45(.73)
3.02(.64)
3.87(.82)
3.92(.83)
4. 01 (.85)
4.n(.B71
4.is(.sa)
Transport
Line Terap
«C(«F)
229(444)
234(453)
-
-
232(449)
232(449)
231(447)
231(447)
236(456)
232(450)
Flow Control
Oven Tenp
•Ct-F)
232(449)
-
-
-
202(396)
218(425)
237(458)
234(45*)
230(446)
229(444)
Organic
Module
Tenp
-cm
14(58)
-
-
-
21(70)
22(72)
23(74)
22(71)
24(76)
24(75)
Inpinger
Train
lemp
'C('f)
21(70)
-
-
-
21<69)
21(69)
21(70)
2?(7)3
23(73}
23(73)
Anfctent
Ten?
°C(*F)
18(65)
18(64)
18(65)
19(67)
19(67)
18(65}
19(66)
U1
I
oo
£T>
f-
CO
3
73
At orifice conditions - see Table 4-2.
cn
-------
TABLE 5-4. ANISOKINETIC CORRECTION FACTORS - PHASE I
Run
1
2
3
Sampl e
Flowrate
m'/sec
(acfm)
4.0 x 10""
(0.85)
4.0 x 10""
(0.90)
4.0 x 10""
(0.90)
Nozzle
Velocity
m/sec
(ft/sec)
2.8(9.3)
4.0(13.0)
3.4(11.3)
Estimated
Duct
Velocity
m/sec
(ft/sec)
2.0(6.7)
1.9(6.3)
2.0(6.7)
Velocity
Ratio
0.72
0.48
0.59
Particle Concentration3
Correction Factor
measured
true
0.99
0.98
0.99
Calculation per method in Handbook of Aerosols, TID-26608, 1976, Section 5.1-1 and Figure 5-2.
-------
system heat losses. Sample conditioning data showed that the sample gas
was cooled below the desired 230°C (450°F) in passing through the
unheated particle collection device. In Run 1, with the filter
collector, minimum temperature after the impactor was 107°C (225°F).
Temperatures did, however, remain above the dewpoint for 97°C
(207°F), 930 kPa (120 psig) 6 percent water (although probably not
above the H2SO. dewpoint). Consequently, no water condensation
occurred during these tests. Correcting the impactor heater malfunction
will eliminate the low collection temperatures in future sampling.
The sample flowrate, 380 cm3/s to 425 cm3/s (0.8 to 0.9 acfm)
at orifice inlet conditions, was maintained within the impactor operating
range throughout the test series. This flowrate gave nozzle velocities
which were somewhat above duct velocity (anisokinetic). The flowrate was
chosen based on the expected stream velocity. Unfortunately, a damaged
pitot tube prevented measuring the velocity to confirm the proper
flowrate needed to maintain isokinetic conditions. However, for the high
gas temperature and pressure, fine particles and low velocities involved,
the variance from isokinetic conditions has no significant effect on
measured particulate concentration. The error in measured particle
content as a function of an isokinetic velocity mismatch can be estimated
analytically (see Figure 5-1). A comparison of duct and sampling
velocities and the calculated correction factors for anisokinetic
conditions is presented in Table 5-4. As shown, the measured particulate
concentrations are within 1 or 2 percent of isokinetic measurements.
Table 5-3 lists the instrument readings from the gas sampling
equipment used during Run 1. Gas sample flow was started shortly after
particulate sampling began, so the total elapsed time is less than shown
71
-------
2.0
1.8
1.6
§ 1-«
Z
O
o
UJ
D
CC
o
tr
UJ
O
o
o
o
UJ
cc
UJ
v>
CO
o
u.
O
1.2
2 1.0
0.6
0.4
0.2
k = 0.005
k = 0.02
k = 0.04
k = 0.08
k = 0.14
. k = 0.32
k = 1.0
0.1
eo
co
"
CcpVd2
18nD
where
d = diameter of particles, cm
p = density of particles, g/cm3
0 = probe diameter, cm
v = probe inlet velocity, cm/sec
V = main stream velocity, cm/sec
n = gas viscosity, poise
Cc = Cunningham correction factor.
dimensionless
I
10
0.3 1 3
VELOCITY RATIO (R)
Figure 5-1. Probe inlet bias (from Reference 3).
72
-------
in Table 5-2. During gas sampling, all sample flow was diverted to the
gas-train, so the flowrates given for the gas train are the same as those
for the parti oil ate collector. The temperature readings show that all
gas train components were operating correctly.
During the test series, the surface temperatures of the access
port, gate valves and probe housing were measured. These readings are
presented in Table 5-5. The gate valve surface temperature remained
below 126°C (258°F) at all times . Accessible surfaces of the probe
housing also remained cool, below 75°C (167°F).
5.2 PHASE I -- DEMONSTRATION TEST RESULTS
The tests produced data on particulate concentration, size
distribution, appearance, chemical composition, and moisture content.
Although trace organic and trace element samples were collected,
demonstrating that particular HTHP system capability, the analysis of
these samples was beyond the scope of the program.
The measured particle concentrations are listed in Table 5-6. The
values of 1.06 to 1.58 g/m3 (0.43 to 0.64 gr/scf) are reasonable
compared to other measurements made in the unpressurized portions of the
3
Exxon process. Those measurements have ranged from 0.5 to 2.96 g/m
(0.2 to 1.2 gr/scf). The 1.58 g/m3 (0.64 g/scf) value from the
30-minute sample is the most accurate measurement from the current
tests. It comes from the largest sample and best defined conditions.
The moisture content measured in Run 1 was 6.2 percent by volume.
This compares well with Exxon's preliminary estimate of 5.8 percent.
Particle size distribution information is presented in Figure 5-2
and Table 5-7. As shown, there is some difference in the results from
73
-------
TABLE 5-5. STRUCTURE TEMPERATURES
Pretest (11:00 a.m., 3-30-77)
Duct Wall 176°C (349°F)
Pressure Cylinder
Top 146°C (294°F)
Side 138°C (280°F)
Bottom 87°C (189°F)
Gate Valve - Duct Side
Top 126°C (258°F)
Side 104°C (220°F)
Bottom 91°C (195°F)
Run No. 1 (3:30 p.m., 3-31-77)
Time
0
10 min
20 min
60 min
Valve-
Probe
Side
64°C(147°F)
71°C(159°F)
69°C(157°F)
88°C(190°F)
Inner
Probe
Housing
56°C(133°F)
55°C(131°F)
56°C(133°F)
N/A
Outer
Probe
Housing
56°C(133°F)
68°C(154°F)
75°C(167°F)
N/A
74
-------
TABLE 5-6. PARTICULATE CONTENT
Run #1
Run
Run #3
Date:
Time:
Particle Catch:
(grams)
Filter
Impactor
Residue
Total
Sample Volume:
m3(scf)
Particle Content:
(9/m3)(gr/scf)
Particle content:
(g/m3)(gr/scf)
(Anisokinetic
Correction Applied)
3-31-77
1530
3.2515
-
1.8565
5.108
3.22(122.5)
1.58(0.64)
1.60(0.65)
4-1-77
1030
-
0.0554
0.0334
0.0884
0.082(3.13)
1.06(0.43)
1.08(0.44)
4-1-77
1500
-
0.0892
0.0595
0.1497
0.132(5.03)
1.13(0.46)
1.16(0.47)
75
-------
100
80
60
40
10
e
E
a.
& A
Hi 4
UJ
o
s.
o.
i.o
0.8
0.6
0.4
0.2
0.1
10
PERCENTAGE UNDERSIZE (BY WEIGHT)
20 30 40 50 60 70 80
90
90 80 70 60 50 40 30
PERCENTAGE OVERSIZE
20
10
98
§
N
4
Figure 5-2. Particle size distribution — Phase I tests.
76
-------
TABLE 5-7. PARTICLE SIZE DISTRIBUTION
Stage
1
2
3
4
5
6
7
Filter
D50
Microns
26.0
12.0
4.3
2.1
1.2
0.6
0.3
Run #2
Weight
Collected
0.0076
0.0080
0.0171
0.0139
0.0022
0.0036
0.0020
0.0010
% Total
Weight
13.7
14.4
30.9
25.1
4.0
6.5
3.6
1.8
%
Smaller
86.3
71.8
41.0
15.9
12.0
5.4
1.8
0.0554 grams
Run #3
Weight
Collected
0.0093
0.008
0.0221
0.0215
0.0135
0.0081
0.0039
0.0028
0.0892 grams
% Total
Weight
10.4
9.0
24.8
24.1
15.1
9.1
4.4
3.1
%
Smaller
89.6
80.6
55.0
31.7
16.6
7.5
3.1
-------
the two impactor runs. However, both show that most of the participate
falls within the 1-to 20-micrometer range.
The impactor substrates are shown in Figures 5-3 through 5-6.
Generally, the patterns are typical of normal impactor operation.
Stage 7, however, shows evidence of several plugged jets. A comparison
of Figures 5-4 and 5-5 show the differences in particulate loading for
substrates from Run 2 and Run 3. Run 2 substrates were lightly loaded,
while those from the longer duration Run 3 showed heavy,
three-dimensional deposits.
The particulate sample from Run 2 were photographed using a
scanning electron microscope (see Figures 5-7 through 5-10). The
particulate is irregular in appearance, suggesting that it may be calcium
sulphate crystals from the dolomite bed and ash from low-temperature
combustion. Some of the photos show congealed masses of particles. The
source of this phenomena could be any of the following: a property of
the collected particulate, condensation on the particulate, or the
conductive spray applied to the sample for SEM photography.
The chemical composition of collected particulate was analyzed by
dispersive X-ray fluorescence analyzer. Spectra of X-ray emissions are
shown in Figure 5-11. The peak heights for each element indicate the
relative elemental concentration. The analysis shows detectable amounts
of aluminum, silicon, calcium, sulphur, iron, potassium, titanium and
copper.
5.3 PHASE II ~ CONDENSATION TEST DATA
5.3.1 Test Conditions
Plant operating conditions are listed in Table 5-8. As in the
Phase I tests, the nominal conditions were similar for all test runs. In
78
-------
Impactor substrates.
Impactor substrates.
Figure 5-3.
79
-------
Impactor substrates.
Impactor substrates.
Figure 5-4.
81
-------
00
Figure 5-5.
Impactor substrate Run 3, Stags 5
-------
oo
n
Figure 5-6.
Impactor substrate — Run 2, Stage 5,
-------
1000X
10 Microns
3000X
Figure 5-7.
Particle photomicrographs Stage 1
87
-------
\ooox
10 Microns
3000X
3 Microns
Figure 5-8.
Particle photomicrographs Stage 2,
89
-------
1000X
10 microns
3000X
3 microns
Figure 5-9.
Particle photomicrographs Stage 4.
91
-------
3000 X
10000X
1 micron
Figure 5-10.
Particle photomicrographs Stage 6.
93
-------
S£^
Stage 1, Run 2
•=COO
U_ O
Stage 6, Run 2
Figure 5-11. Particle checmical composition.
95
-------
TABLE 5-8. EXXON - PHASE II FBC OPERATING CONDITIONS
Run
Date
Sampling Time
Ambient Temperature °C(°F)
Bed Conditions
Temperature °C(°F)
Combustor Pressure
kPa(atm)
Ca/Sulphur Ratio
Coal
Dolomite
Combustor Flowrate -
sm^/mi n
Avg. Duct Velocity -
^
n/s
m/sec(ft/sec)
1
5-24-77
1433 - 1503
32(90)
893(1640)
932.2
1.25
CHAMPION
PFZIZER
16.5(628)
2.43(7.97)
2
5-24-77
0900 - 0920
29(85)
891(1635)
932.2
1.25
CHAMPION
PFZIZER
16.6(630)
2.44(7.99)
3
5-24-77
1134 - 1153
29(85)
893(1640)
922.1
1.25
CHAMPION
PFZIZER
16.6(631)
2.44(800)
4
5-24-77
1700 - 1715
31(88)
896(1644)
922.1
1.25
CHAMPION
PFZIZER
16.8(639)
2.47(8.11)
-------
fact, the test conditions for both phases of testing were very similar.
Champion coal from the same shipment and Pfzizer dolomite were used for
all testing. Combustor flowrate and average duct gas velocity were
approximately 15 percent greater in the Phase II tests. The facility ran
steadily with no interruptions during the tests.
5.3.2 Instrument Readings
The Phase II sampling system employed the same instrumentation
control modules as the Phase I tests. Readings of duct, sample and
equipment operating conditions are presented in Table 5-9.
The stack gas thermocouple malfunctioned throughout the four
tests. This temperature was approximated at 732°C (1350°F) -- the
average stack temperature during the first test series. Very similar
PFBC operating conditions between the two test series make this a
reasonable approximation. Another less critical malfunction occurred in
the transport tube outlet filter thermocouple. This problem had the
nature of an intermittent electrical short. Consequently, the
measurement could be made only periodically.
The sample conditioning data showed the sample temperature falling
below the target of 232°C (450°F). Temperatures sometimes fell as
low as 93°C (200°F) immediately after the flow control valve and
rarely exceeded 204°C (400°F) in the transport tube leading to the
final filter. Assuming that flue gas S03 concentrations are below
30 ppm, as they are in conventional fossil fuel fired boilers, then
Figure 5-12 indicates the H2S04 dewpoint temperature to be between
177°C (350°F) and 204°C (400°F). Consequently, it should be
expected that formation of sulfuric acid mist occurred in the transport
tube. Upon analysis of the rear filter catch, this was found to be the
98
-------
TABLE 5-9. PROBE INSTRUMENTATION READINGS
Run No. 1
5-24-77 Tues.
Zero Point
Closed Ball Valve
Retract Probe
Run No. 2
5-24-77 Tues.
Zero Point
Closed Ball Valve
Retract Probe
Time
of
Day
1333
1351
1358
1404
1408
1412
1416
1420
2100
2105
2110
2115
2119
2122
Elasped
Time
(Mln)
0
5
10
15
20
25
29
30
Stop-off
0
0
5
10
15
19
20
Stop-off
Stack
Pressure
kPa(psl)
882.5(128)
765.3(111)
758.4(110)
758.4(110)
758.4(110)
758.4(110)
758.4(110)
758.4(110)
765.3(111)
758.4(110)
758.4(110)
765.3(111)
765.3(111)
765.3(111)
765.3(111)
Stack
Temp
•cm
M
M
-
-
M
-
-
510(950)
493(920)
493(920)
493(920)
493(920
Dow therm
Inlet
Temp
•C('F)
185(365)
188(370)
182(360)
188(370)
189(372)
188(370)
189(372)
188(370)
182(360)
188(370)
185(365)
187(368)
189(372)
189(372)
182(360)
Dowtherm
Outlet
Temp
*C(°F)
188(370)
193(380)
188(370)
193(380)
194(372)
193(380)
194(381)
188(370)
188(370)
193(380)
193(380)
193(380)
194(381)
188(370)
Traverse
Tube Heater
Temp
2 'C(°F)
206(403)
201(394)
203(397)
203(397)
202(395)
201(393)
202(395)
202(395)
209(409)
203(397)
203(398)
204(400)
206(402)
rintnrf
208(407)
Traverse
Tube Outlet
Temp
3 °C(°F)
41(106)
102(215)
122(252)
125(257)
124(255)
129(265)
129(264)
71(160)
36(97)
141(285
148(298)
144(291)
144(291)
l/j.1 ,,n
Value
86(187)
Traverse
Tube Outlet
Filter Temp
4 «C(°F)
33(91)
34(93)
33(92)
33(92)
34(93)
33(92)
34(93)
33(92)
33(91)
163(325)
173(344)
174(345)
176(349)
84(183)
Sample
Flowrate
ro'/sec x 10"*
(acfm)
2.41(.51)
2.4K.51)
2.41(.51)
2.4K.51)
2.4K.51)
2.4K.51)
2.41(.51)
2.41(.51)
2.41(.51)
2.41(.S1)
2.41(.51)
2.41(.51)
2.41(.51)
2.4K.51)
Transport
Tube Temp
°C(°F)
277(530)
277(530)
277(530)
277(530)
277(530)
277(530)
277(530)
OFF
293(560)
293(560)
249(480)
254(490)
257(495)
257(495)
OFF
Note: M Indicates malfunction
-------
TABLE 5-9. (Concluded)
Run No. 3
5/25/77, *d.
Zero Point
Prtstart
Closed Ball Vtlvt
Run No. 4
5/25/77. Wed.
Ball Valve Cloud
Time
Of
Day
11:12 . ,
11:18 . .
11:34 . .
11:41 . .
11:46 . .
11:51
11:58
4:55 p.m.
5:00 p.m.
5:02 p.m.
5:07 P.M.
5:11 P.M.
Elapsed
Time
(rin)
-5
0
0'
5
10
15
19
Stopoff
-5
0
5
10
14
is
01
Stack
Pressure
kPi (psl)
834.3 (121)
841.2 (122)
765.3 (111)
765.3 (111)
765.3 (111)
765.3 (111)
765.3 (111)
634.3 (121)
765.3 (111)
765.3 (111)
765.3 (111)
765.3 (111)
Stack
Temp.
•c ft)
H
H
M
N
M
H
M
N
N
H
N
M
Stopoff
M
Dowtherm
Inlet
Temp.
•C (*F)
188 (370)
189 (372)
188 (370)
194 (382)
191 (375)
188 (370)
177 (350)
191 (375)
196 (385)
192 (378)
193 (380)
196 (385)
179 (355)
Dowtherm
Outlet
Temp.
•C («F)
188 (371)
188 (370)
188 (370)
198 (389)
193 (379)
188 (370)
182 (360)
189 (372)
199 (390)
193 (380)
194 (381)
197 (387)
182 (360)
Traverse
Tube
Heater
Temp.
•C ("F)
211 (411)
208 (407)
211 (411)
206 (405)
206 (403)
206 (402
87 (188)
206 (402)
199 (390)
201 (394)
202 (396)
201 (394)
fait1* Ihwn
Off
Traverse
Tube
Inlet
Temp.
•C CF)
36 (97)
37 (99)
38 (100)
149 (300)
152 (305)
152 (305
79 (175)
41 (105)
135 (275)
151 (303)
148 (299)
142 (288)
78 (173)
Traverse
Tube
Outlet
Filter
Temp.
•C (*F)
34 (93)
35 (95)
37 (98)
172 (341)
177 (351)
179 (354)
._
35 (95)
158 (316)
171 (340)
173 (344)
172 (341)
Sample
Flow Rate
m'/sec x 10'*
2.41 (0.51)
2.41 (0.51)
2.41 (0151)
2.41 (0.51)
2.41 (0.51)
2.41 (0.51)
2.41 (0.51)
2.41 (0.51)
2.41 (0.51)
2.41 (0.51)
2.41 (0.51)
2.41 (0.51)
2.41 (0.51)
Transport
Tube
Temp.
*C (*F)
266 (510)
271 (520)
282 (540)
268 (515)
268 (515)
268 (515)
Off
263 (505)
271 (520 L
266 (510)
266 (510)
271 (520)
Off
o
o
-------
10130 (100)
1 3 10 30 100
1013 (10)
£
re
re
-------
case (see following section). This analysis also showed contamination
from the disintegration of control valve packing located just upstream of
the rear filter.
Sampling flowrates were predetermined by assuming a duct velocity,
pressure and temperature, based on the Phase I tests, and appropriately
sizing a nozzle and the choked orifices to yield isokinetic nozzle
velocities. The actual sample flowrate gave nozzle velocities
approximately 15 percent below duct velocities. However, as was the case
with the Phase I tests, the high gas temperatures and pressures, the fine
particles and low velocities involved minimized the effect of
anisokinetic conditions on the measured particulate concentration.
Furthermore, since the purpose of the Phase II tests was to examine only
elemental concentrations in the hot and cold filters, particle size
biasing caused by anisokinetic sampling conditions was relatively
unimportant. A comparison of duct and sampling velocities and the
calculated correction factors for anisokinetic conditions is presented in
Table 5-10. The measured particulate concentrations are within 3 percent
of the true concentration.
5.4 PHASE II - CONDENSATION TEST RESULTS
The condensation test results section is divided into three
subsections. General results and observations of the samples, both
visually and by photomicrographs, are discussed first. Attempts at
comparing the analyses of the hot and cold filter catches and the
associated problems are treated next. Finally, an alternate approach to
answering the question of condensation of trace elements is discussed.
Tentative conclusions are drawn from the limited data obtained.
102
-------
TABLE 5-10. ANISOKINETIC CORRECTION FACTORS - PHASE II
Run
1
2
3
4
Sample
Flowrate
m3/s x 10""
(acfm)
2.4(.51)
2.4(.51)
2.4(.51)
2.4(.51)
Nozzle
Velocity
m/sec
(ft/sec)
2.2(7.1)
2.2(7.1)
2.2(7.1)
2.2(7.1)
Estimated
Duct
Velocity
m/sec
(ft/sec)
2.4(8.0)
2.4(8.0)
2.4(8.0)
2.4(8.1)
Velocity
Ratio
1.13
1.13
1.13
1.14
Particle Concentration3
Correction Factor
measured
true
1.03
1.03
1.03
1.03
Calculation per method in Handbook of Aerosols, TID-26608, 1976,
Section 5.1-1 and Figure 5-2.
-------
5.4.1 General Results and Observations
Table 5-11 shows particulate concentration. As noted, Run No. 3
samples were, retained by EPA for SSMS analysis and, consequently, not
weighed. The reported values for particulate catch have been obtained by
using standard EPA drying and weighing techniques. The values of 0.99 to
2.49 g/m3 (0.40 to 1.01 gr/scf) are reasonable compared to other
measurements made on the FBC. As stated earlier, these values have
ranged from 0.49 to 2.96 g/m3 (0.2 to 1.2 gr/scf) on a wet basis.
A flue gas moisture content of 6 percent could be assumed if it is
desired to obtain dry basis particulate concentrations. This is an
approximate value from the Phase I test series.
Visual observations of the front and rear filters from Tests 1, 2,
and 4 are summarized in Table 5-12. In addition, all these samples were
photographed using a scanning electron microscope.
As in the first test series, the particulate is irregular in
appearance, suggesting that it may be calcium sulfate crystals from the
dolomite bed and ash from low-temperature combustion. However, some of
this particulate is undoubtedly gold deposited as a result of corrosion,
blistering, and flaking of the gold plating on the scalping cyclone.
Chemical analysis of the hot filter catch showed considerable gold
concentrations — many times greater than would be expected in flyash.
This gold contamination has little negative effect on the condensation
test results. The photographs in Figures 5-13 and 5-14 show agglomerated
particles. For the front filter, the cause could be either a property of
the collected particulate or the conductive spray applied to the sample
104
-------
TABLE 5-11. PARTICULATE CONCENTRATION
Run #1
Run #2
Run 14
Date
Time
Participate Catch
(grams)
Cyclone
Front Filter
Rear Filter
Probe Wash
TOTAL
Sample Volume
NmMscf)
Particle Content
g/m3/(gr/scf)
Particle Content
g/mV(gr/scf)
(Anisokinetic
Correction Applied)
5-24-77
1445
1.414
.374
.014
.266
2.068
2.05(78)
1.01 (.41)
.99(.40)
5-24-77
0910
2.354
.654
.014
.469
3.491
1.37(52)
2.56(1.04)
2.49(1.01)
5-25-77
1710
1.243
.598
.006
.359
2.206
1.03(39)
2.14(.87)
2.07(.84)
Note: Run 3 samples retained by EPA for SSMS analysis - no weights
available.
105
-------
TABLE 5-12. VISUAL OBSERVATION OF FILTERS - PHASE II
Front
(all disintegrating)
Flesh color - fine particles
light loading
Flesh color - fine particles
medium loading
Flesh color - fine particles
medium loading
Rear
Dark tan - very few metal lie-like
particles, medium coating of
fine particles
Dark tan - more metallie-like
particles, medium coating of
fine particles
Grey with a tan tinge - many
metallic-Tike particles,
light coating of fine particles,
4- to 5-mm hole either abraded
or corroded in center of filter
Note: No observations made on Test 3 - filters given to
EPA for SMS analysis.
106
-------
-.-•
c
L
3 microns
3000 X
n
E.
1 micron
Figure 5-13.
10000 X
Particle photomicrographs -- Run 1, front filter.
107
-------
c
=«=
T3
CD
O
C
• I
3 microns
i
I
1 micron
10000 X
Figure 5-14. Particle photomicrographs -- Rund 4, front letter.
109
-------
for SEM photography. For the rear filters, shown in Figures 5-15 and
5-16, these causes are again possibilities, in addition to the known
existence of H^SO, condensation and valve packing contamination.
The rear filter for Test 4, shown in Figure 5-15, is noticeably
lighter in particulate than Tests 1 and 2 rear filters (Figure 5-13).
This is because two front filters were used in Test 4 while only one was
used in Tests 1 and 2. Figure 5-17 shows a photograph and a dispersive
X-ray analysis of a blank rear filter. Dispersive X-ray fluorescence
analysis for the Test 4 front filter (Figure 5-18) shows detectable
amounts of aluminum, silicon, sulfur, potassium, calcium, titanium, and
iron. The rear filter analysis from the same test shows that the
compounds of most elements almost completely filtered out in the front
filter.
The cyclone used was a Southern Research Institute model designed
for much less severe operating temperatures. It was readily available,
was small enough for insertion into the duct, and had a very efficient
0.6 micron cutpoint. As previously mentioned, the cyclone's protective
gold plating blistered and peeled, leaving titanium surfaces exposed to
heavy oxidation. Chemical analysis of the particulate samples showed
significant gold contamination in the cyclone and front filter catches
but none in the rear filter catch. Titanium contamination was not
evident in any of the samples.
5.4.2 Initial Analyses for Condensation Effects
The original intention of the Phase II tests was to compare the
elemental concentrations found in the filtered material of the in-stack
scalping cyclone and backup filter with the material caught on the rear
filter. If the system worked ideally, one could assume all the material
111
-------
ro
a;
3 microns
3000 X
re
-------
t
I
3 microns
-
=«=
N
W
10000 X
1 micron
Figure 5-16. Particle photomicrographs -- Run 1, rear filter.
115
-------
_^
c
-:
I
1 micron
10000 X
Particle photomicrograph — blank rear filter.
*
c
03
CO
Particle chemical composition - blank rear filter.
Figure 5-17.
117
-------
c
o
S-
a; o;
Front filter
-
-
- :
:
-------
on the rear filter was in a gaseous state at stream conditions and would
thereby pass through the hot cyclone/filter combination and thus be
indicative of condensation products produced within the probe.
Unfortunately, the rear (or cold) filter could not be reliably analyzed.
Carryover of glass fiber filter material during sample preparation (the
small amount of the sample available on the cold filter and additional
contamination already mentioned), yielded poor detection limits with the
spark source mass spectrometer (SSMS). Moreover, the values reported for
this filter were in mass units rather than concentration units because a
net filter collection weight was not determined. This made any direct
comparisons of cold and hot catches from Phase II results alone difficult
if not speculative.
Samples of the probe wash were analyzed by Arthur D. Little, Inc.,
to determine the source of the suspected contamination of the rear
filter. A sample from each test was analyzed by thermal gravimetric
analysis (T6A), infrared analysis (IR), X-ray fluorescence (XRF), and low
resolution mass spectra (LRMS). Results indicated there were three
sources of contamination. They were by weight: (1) approximately 30
percent particulate ~ attributed to hot, in-stack filter breakthrough,
(2) approximately 25 percent sulfuric acid and sulfate condensate --
attributed to localized cold spots (measured at 200°F, below the
H2S04 condensation temperature), and (3) approximately 40 percent
organics — later attributed to the disintegration of packing material
from a valve located just upstream of the rear filter. The evidence of
breakthrough particulate contamination was supported by photomicrographs,
which showed similar appearance between material on the front and rear
filters, and by dispersive fluorescent X-ray spectrum which shows a
121
-------
similarity in chemical composition. The sulfur content did, however,
increase on the rear filter, apparently as a result of sulfate
condensation.
5.4.3 Alternate Approach
An alternate approach was taken to resolve the question of trace
metal condensables. During the Phase I demonstration tests at Exxon, a
test run was made at essentially the same operating and stream conditions
as the Phase II tests. A total mass filter was used in place of the
cascade impactor and was maintained at about the same temperature as for
Phase II. Northrop Services, Inc. performed a SSMS analysis of the
Phase I bulk filter catch, as they did with the Phase II hot
cyclone/filter samples.
Table 5-13 presents the results for these analyses. The measured
elemental content is similar to common flyash. A partial,
nondimensionalized comparison of these two sets of results, Phase I and
Phase II, is presented in Table 5-14. Reference quantities Fe and Mg,
have been chosen to nondimensionalize the results because they exist in
significant concentrations in each sample and are not likely to be
present as a result of contamination. Nondimensionalizing was done
because there appeared to be a diluent present in the Phase I sample
filter catch. The Si concentrations indicate that the filter material
itself may be the diluent in the sample. In fact, the sample analyst
acknowledged some difficulty with separating the sample from the
filtering media prior to analysis.
Aside from the silicon results, comparison of the other quantities
shown indicates that there was no detectable change in the concentration
of Na or K from the hot to cold particulate catches. It should be
122
-------
TABLE 5-13.
CONCENTRATION OF ELEMENTS IN FLYASH
SSMS ANALYSIS (PARTIAL)
Element
K
Na
Rb
/%_
cs
Al
S1
Fe
Ca
Mg
T1
Sr
Ba
A..
Au
P
Cu
Zr
N1
Cr
Pb
Cyclone
(ppm)
8,200
1,310
< 70
67
./
164,000
94,000
30,000
20,000
11,400
2,430
810
710
£cn
650
276
248
160
120
< 90
85
TEST #3
Front
(ppm)
8,850
2,500
< 68
oo
.tO
94,000
82,600
13,400
19,000
17,800
1,950
555
694
1 1 Q
1 10
223
165
140
100
< 140
75
- PHASE II
Rear
(ppm)
15.1
< 135. *
< .43 *
^ co *
< .DC
64.2
<2510. *
60.
< 6.6 *
38.
7.1
.6
< 5.0
x 1 A
< \ .H
< 224. *
< 1.5 *
< 2.1 *
5.8
< 13.1
< 4.0 *
Rear Blank
(ppm)
5.4
91.
.13
6.4
1210.
2.36
7.3
5.9
3.1
1.15
1.5
68.
.91
.64
.29
6.4
1.2
PHASE I
Bulk Filter
(ppm)
16,250
3,560
866
80
• o
Major
310,000
36,300
44,000
28,600
10,600
1,320
1,080
?n
C. t O
1,880
142
334
348
366
86
ro
co
Notes: < - natural background limited detection limit
<* - blank limited detection limit
-------
TABLE 5-14. PARTIAL COMPARISON OF FRONT AND REAR PARTICULATE
CATCHES FROM EXXON TEST SERIES I AND II
K
Na
Fe
S1
Fe
Ca
Fe"
Mg.
Fe
Sr
Fe
Ba
Fe"
K
M?
Na
*?
S1
Mg
Fe
Mg
Ca
M?
Sr
M?
Ba
Mg
Phase I Tests
Bulk Filter
0.45
0.10
8.54
1.23
0.79
0.04
0.03
0.57
0.12
10.84
1.27
1.56
0.05
0.04
Phase II Tests
Cyclone Front Filter Avg.
0.27 0.66 0.47
0.04 0.19 0.12
3.13 6.16 4.65
0.67 1.42 1.05
0.38 1.33 0.86
0.03 0.04 0.04
0.02 0.05 0.04
0.72 0.50 0.61
0.11 0.14 0.13
8.25 4.64 6.45
2.63 0.75 1.69
1.75 1.07 1.41
0.07 0.03 0.05
0.06 0.04 0.05
Ratio
0.96
0.83
1.84
1.17
0.92
1.00
0.75
0.93
0.92
1.68
0.75
1.11
1.00
0.80
124
-------
stressed that these are very limited data from two tests taken at
different times comparing hot and cold filter catches. However, the PFBC
was using the same coal and dolomite under very similar operating
conditions for both tests, thereby supporting the validity of the
comparison. Further testing is recommended to provide data points at
other PFBC operating levels and possibly with different filtering media
and collection temperatures.
125
-------
SECTION 6
CONCLUSIONS
The sampling system described in this report demonstrates that
extractive sampling is a feasible approach for sampling high-temperature,
high-pressure processes. In addition, the limited data obtained at one
PFBC operating level during the Phase II condensation tests, seems to
indicate that trace element condensation would have minimal effect on
particulate composition collected at a low temperature (approximately
400°F). Technology for sampling pressurized fluidized bed combustors
is now developed and available. Future development also will be required
to make useful application of this technology and extend it to other
advanced coal conversion processes.
One of the remaining issues for FBC high-temperature,
high-pressure sampling is system cost/performance trade-offs. Process
developers seem to be interested in both upgraded and downgraded versions
of the sampling system. Upgraded versions offer longer sampling
durations, quicker turnaround and better operating convenience.
Downgraded versions, such as fixed-probe designs, are cheaper, but give
less information.
126
-------
The next objective for extractive sampling is to develop sampling
technology for gasifiers. Participate measurement is also important for
developing these processes, and environmental difficulties are even more
severe than for PFBC's.
127
-------
REFERENCES
1. Hamersma, J. W., et. al., "IERL-RTP Procedures Manual: Level 1
Environmental Assessment," EPA-600/2-76-160a, June 1976.
2. JANAF, "Thermochemical Tables," Second Edition, the Thermal Research
Laboratory, Dow Chemical Company, Midland, Michigan, 1971.
3. Dennis, Richard, "Handbook on Aerosols," U.S. Energy Research and
Development Administration, 1976.
128
-------
TECHNICAL REPORT DATA
(Please read tmtructions on the reverse before completing)
1. REPORT NO. 2.
EPA-600/7-78-158
4. TITLE AND SUBTITLE
Sampling System Evaluation for High-temperature ,
High-pressure Processes
7. AUTHOR(S)
William Masters, Robert Larkin, Larry Cooper,
and Craig Fong
&. PERFORMING ORGANIZATION NAME AND ADDRESS
Acurex Corporation/Energy and Environmental Division
485 Clyde Avenue
Mountain View, California 94042
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
August 1978
6. PERFORMING ORGANIZATION CODE
8, PERFORMING ORGANIZATION REPORT NO,
10. PROGRAM ELEMENT NO.
EHE623 and 624
11. CONTRACT/GRANT NO.
68-02-2153
13. TYPE OF REPORT AND PERIOD COVERED
Final; 3/76-7/77
14. SPONSORING AGENCY CODE
EPA/600/13
is. SUPPLEMENTARY NOTES J.ERL-RTP project officer is William B. Kuykendal, Mail Drop 62,
919/541-2557.
16. ABSTRACT The report describes a sampling system designed for the high temperatures
and high pressures found in pressurized fluidized-bed combustors (PFBC). The sys-
tem uses an extractive sampling approach, withdrawing samples from the process
stream for complete analysis of particulate size, mass concentration, shape, and
chemical composition. Two series of tests were run at Exxon's pilot-scale PFBC
in Linden, New Jersey: the first was run to measure particulate mass and size distri-
bution (particulate sizing was achieved using a commercial cascade impactor opera-
ting at about 105 C); the second was run to determine if condensation occurred between
the process temperature of 720 C and the impactor temperature. Results show that
cascade impactors can be successfully used for sizing in the high-temperature, high-
pressure process stream of the PFBC, and that condensation was not a problem in
the tests conducted.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Pollution
Sampling
Extraction
Evaluation
High Temperature
Tests
Condensing
8. DISTRIBUTION STATEMENT
Unlimited
High Pressure Tests
Fluidized Bed Pro-
cessors
Analyzing
Dust
Impactors
b.lDENT!FIERS/OPEN ENDED TERMS
Pollution Control
Stationary Sources
Particulate
Mass Concentration
Cascade Impactors
19. SECURITY CLASS (This Report)
Unclassified
2O. SECURITY CLASS (This page)
Unclassified
c. COSAT1 Field/Group
13B
14B
07A/13H 131
11G
07D
21. NO. OF PAGES
134
22. PRICE
PA Form 2220-1 (9-73)
129
------- |