oEPA
United States Industrial Environmental Research EPA-600/7-78-166
Environmental Protection Laboratory August 1978
Agency Research Triangle Park NC 27711
Design and
Construction of a
Fluidized-bed
Combustion
Sampling and
Analytical Test Rig
Interagency
Energy/Environment
R&D Program Report
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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
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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)
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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 goaf 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
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This report has been reviewed by the participating Federal Agencies, and approved
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This document is available to the public through the National Technical Informa-
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EPA-600/7-78-166
August 1978
Design and Construction of a
Fluidized-bed Combustion
Sampling and Analytical Test Rig
by
H. Dehne
Acurex Corporation/Energy and Environmental Division
485 Clyde Avenue
Mountain View, California 94042
Contract No. 68-02-2170
Program Element No. EHE623A
EPA Project Officer: John H. Wasser
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
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DISCLAIMER
This report has been reviewed by the Environmental Protection Agency
and approved for publication. Approval does not signify that the contents
necessarily reflect the views and policies of the Environmental Protection
Agency, nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
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ABSTRACT
A Flu1d1zed-Bed Coal Combustion Sampling and Analytical Test Rig was
designed, fabricated and installed in the High Bay area (Wing G) of the
Industrial Environmental Research Laboratory (IERL) at Research Triangle Park,
North Carolina to be used by IERL for research programs. It is a research
tool where the design philosophy was based on considerations of flexibility,
accuracy and utility. The system operating ranges are:
Coal feedrate - 10 to 50 kg/hr (22 to 110 Ibm/hr)
Sorbent feedrate - 0 to 25 kg/hr (0 to 55 Ibm/hr)
Excess air - 10 to 300 percent
Bed temperature - 750°C to 1100°C (1380°F to 2010°F)
Fluidizing velocity - 1 to 5 mps (3 to 16 fps)
The purpose of this project was to provide EPA with the capability to investigate
the emission characteristics of fluidized-bed combustors.
The program was completed in three phases: preparation of the conceptual
design; preparation of the final design; purchase, fabrication, installation, and
checkout, testing and documentation.
During the conceptual design phase the capability of sampling the
composition of all process streams was especially considered. Recommendations
were made for sampling and analytical procedures and equipment to measure
pollutants of interest. At least four particulate control devices were to be
incorporated in the design. They were a conventional inertial separator, a
"tornado-type" cyclone, a fabric filter and an electrostatic precipitator.
Emphasis was placed on the approximation of full-scale conditions as closely
as possible and to minimize the manpower required to conduct tests and change
conditions between tests.
VI
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The final design was carried out in sufficient detail to enable the
purchase, fabrication and installation of the unit.
The equipment was procured, fabricated and installed in accordance with
the requirements set forth in the drawings and specifications in Phase II of
the program.
Upon completion of the installation an acceptance test was conducted
to demonstrate that the system was completed in accordance with the approved
design and that all equipment was properly installed to serve its intended
purpose.
An operating manual and as-built drawings have been submitted.
This work was submitted in fulfillment of Contract Number 68-02-2170
by Acurex Corporation, Energy and Environmental Division under sponsorship of
the Environmental Protection Agency.
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TABLE OF CONTENTS
Section
ABSTRACT iv
ILLUSTRATIONS viii
TABLES x
ACKNOWLEDGMENT xiv
1 INTRODUCTION 1-1
2 EQUIPMENT DESCRIPTION . . 2-1
2.1 General Arrangement 2-1
2.2 Combustor 2-8
2.3 Air System 2-13
2.4 Solid Feed System 2-16
2.4.1 Introduction 2-16
2.4.2 Storage Bins 2-20
2.4.3 Feeders 2-20
2.4.4 Loadcells 2-21
2.4.5 Vibrators 2-21
2.4.6 Pressure Relief 2-22
2.5 Gas Cleanup System 2-22
2.5.1 Primary Cyclones 2-22
2.5.2 Tornado Cyclone 2-23
2.5.3 Electrostatic Precipitator . 2-24
2.5.4 Baghouse 2-25
2.6 Flue Gas Heat Exchangers and Soot Blowing
Lance 2-26
2.7 Control System . 2-29
2.7.1 Introduction 2-29
2.7.2 Control Systems ~ Panels 2-31
2.7.3 Process Variables ~ Oxygen and Combustibles
Analyzer 2-45
2.7.4 Safety Interlocks 2-47
2.7.5 Instrument Listings 2-47
3 FACILITY OPERATION 3-1
3.1 System Characteristics 3-1
3.1.1 Operating Preparations and Configurations . . . 3-10
3.1.2 Startup 3-14
3.1.3 Shutdown 3-21
viii
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TABLE OF CONTENTS (Concluded)
Section Page
3.2 Combustor Operation 3-22
3.3 Air System Operation 3-26
3.4 Solid Feed System 3-31
3.4.1 Safety Considerations . 3-31
3.4.2 Solid Feed System Calibration and Setup .... 3-35
3.5 Gas Cleanup System Operation 3-40
3.6 Flue-Gas Heat Exchanger and Soot-Blowing Lance
Operation 3-42
3.7 Emergency Shutdown 3-43
4 FBC TEST RIG SAMPLING AND ANALYSIS 4-1
5 TRAINING AND ACCEPTANCE TEST 5-1
6 RAW MATERIALS SOURCES, HANDLING, AND PRICES ....... 6-1
7 SAMPLING SUPPORT FEATURES 7-1
ix
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LIST OF ILLUSTRATIONS
Figure Page
2-1 General arrangement drawing 2-2
2-2 General arrangement drawing 2-3
2-3 General arrangement drawing 2-4
2-4 General arrangement drawing 2-5
2-5 Combustor 2-9
2-6 Air system schematic 2-14
2-7 Solids feed system 2-17
2-8 Solids feed system 2-18
2-9 Flue gas heat exchanger 2-27
2-10 Soot blowing lance 2-28
2-11 P&ID 2-32
2-12 Control console 2-33
2-13 Main control console solids feed system panels . . . 2-37
2-14 Pneumatic diagram 3-38
2-15 Air ejector nomenclature 3-40
2-16 Ejector pressure rise vs. air flow 2-41
2-17 Pneumatic control console 2-42
3-1 Air flowrate versus coal flowrate 3-5
3-2 Fluidizing velocity versus total gas flowrate 3-6
3-3 FBC test rig system schematic 3-9
3-4 Main air flow versus pressure drop 3-16
3-5 Coolant flow versus pressure drop 3-19
3-6 Secondary air and FGR versus pressure drop 3-27
3-7 Air flowmeter AP versus sdnr/min (scfm) 3-28
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LIST OF ILLUSTRATIONS (Concluded)
Figure Page
4-1 FBC test rig sampling locations 4-9
4-2 Typical analyzer conditioning system 4-15
4-3 High volume stack sampler (HVSS) 4-21
4-4 Tenax module and vaporous trace element impinger
train 4-23
4-5 SASS train sampling and analysis 4-25
7-1 FBC test rig sampling locations . . 7-2
XI
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LIST OF TABLES
Table Page
2-1 Air Supply System Instrumentation 2-35
2-2 Solids Feed System Instrumentation 2-43
2-3 Fluidized Bed Combustion Unit Instrumentation 2-44
2-4 Flue Gas Cleanup System Instrumentation 2-46
2-5 Safety Interlocks 2-48
2-6 Instrument Nomenclatures 2-49
2-7 Temperature Selector Switch Indication 2-54
3-1 Design Point Conditions 3-2
3-2 Combustor Design Point Energy Balance kJ/hr
(Btu/hr) 3-3
3-3 Flow and Temperature Design Ranges 3-7
3-4 Design Point Pressure Distribution 3-8
3-5 Distributor Plate Flow Range 3-11
3-6 Solids Feed System Specifications 3-32
3-7 Suggested Vibrator Timer Setpoints 3-39
4-1 Sampling Services Contractors 4-2
4-2 Potential Analytical Contractors 4-4
4-3 Example List of Chemical and Physical Forms of
Pollutants of Concern: Pollutant Chemical Forms ... 4-5
4-4 Sampling and Analytical Methods Summary 4-10
4-5 Sampling Locations and Requirements 4-12
4-6 Online Pollutant Analyzers 4-16
4-7 Coal and Ash Analyses 4-29
Xll
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LIST OF TABLES (Concluded)
Table Page
6-1 Sunroary of Selected Coals 6-3
6-2 Coal Transportation Costs from Mine to Cincinnati . . . 6-5
6-3 Typical Analyses of Limestones and Dolomites 6-7
6-4 Source and Cost of Sorbent Materials 6-9
7-1 Sampling Locations and Requirements 7-3
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ACKNOWLEDGMENTS
The author wishes to express his appreciation to the many
individuals who contributed to this program at Acurex Corporation. I wish
to thank the members of the design team; Hal Williams, Jim Gotterba,
Bob Fulton, George Deutsch, for the special efforts expended. Particular
thanks also go to Robert Larkin and Carlo Castaldini for their
contributions to the reports and special thanks to the publications
department.
The personnel of the Industrial Environmental Research Laboratory
of the EPA are recognized for their role in achieving this goal. Special
thanks go to J. Wasser the EPA Project Officer and Walt Steen.
xiv
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SECTION 1
INTRODUCTION
The need for environmentally acceptable coal-based steam and power
generation processes gave rise to this project. As stated in the Scope of
Work.
"Fluidized-bed combustion (FBC) offers the potential for coal-based
steam and power generation with low environmental impact, and at
the same time with improved thermal efficiency and reduced manpower
costs in comparison with conventional boilers. It is important to
completely characterize emissions from FBC units. The purpose of
this project is to provide EPA with the capability to investigate
the emission characteristics of fluidized-bed combustors. The
major goals of the test rig schedule are:
0 Sampling the wide range of potential contaminants
t Testing alternative sampling and analytical techniques
Testing alternative control devices."
The contract called for the design, fabrication and installation in
the High Bay area (Wing G) of the Industrial Environmental Research
Laboratory (IERL) at Research Triangle Park, North Carolina of a
fluidized-bed combustion sampling and analytical test rig and auxiliary
equipment that would be used for IERL in-house research programs. The
test rig was to be a research tool and the design philosophy should stress
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operational feasibility, accuracy and utility. Flexibility was required
to allow the operation in a wide range of interest, accuracy to be able to
draw significant conclusions from the experiments and utility to allow
economic operation of the facility.
The program called for a program in three phases.
Phase I : Determination of Conceptual Design
Phase II : Preparation of Final Design and
Phase III: Purchase, Fabrication and Installation
The conceptual design considered specifically the identification of
requirements and based upon these requirements a conceptual design was
prepared. The requirements were the approximation of full-scale
conditions, the capability to sample the composition of all process input
and output streams, recommendations of sampling and analytical procedures,
the inclusion of four particulate control devices, the ease of subsequent
additions and testing of control devices, the flue and combustion
conditions and considerations of solids handling.
Based upon the requirements identified a conceptual design was
prepared and submitted. Included in the design package were schematic
drawings and flow sheets, drawings and specifications of key components,
material and heat balances, equipment and instrument lists and discussions
of methods of solids handling and subsequent addition of add-on control
devices.
Upon completion and approval of the conceptual design the final
design was generated. Detailed component and construction drawings were
prepared along with equipment duty and performance specifications. The
final process flow analysis verified the material and energy balance. The
1-2
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fate of all input and output streams was determined and a survey of new
material sources and prices was conducted.
The final design was approved and the Phase III begun and
completed. Tasks completed under the Phase III program were the hardware,
fabrication and installation, the preparation of an operating manual,
personnel training, the acceptance test and as-built drawings.
The objective of the program was accomplished. Section 2 of the
report details the fluidized-bed sampling and analytical test rig
construction and Section 3 the operation of the test rig.
The procedures and equipment to be used for sampling and analysis
are discussed in Section 4.
Section 5 discusses the acceptance test and results and Section 6
the raw material sources and prices.
1-3
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SECTION 2
EQUIPMENT DESCRIPTION
2.1 GENERAL ARRANGEMENT
The FBC Test Rig located at Research Triangle Park in the Wing G
Facility was built to allow the evaluation of a number of different pollu-
tion control devices for fluidized bed flue gas control applications. The
fluidized bed essentially provides the flue gases to be controlled. To
permit comparison studies to be conducted, control devices can be exchanged
by connecting these devices onto convenient locations in the system. All
major components in the system were placed along the Wing G mezzanine floor
to allow easy access to the flue gas ducting for sampling and servicing.
The following requirements were considered important in the design:
Size of components
Reconfiguration capability
Normal traffic patterns
0 Solids handling and storage
Forklift accessibility
0 Sampling port location and sampling convenience
The general arrangement drawings presented in Figures 2-1 through
2-4 show the FBC Test Rig major components. The major features of the sub-
systems are briefly presented below.
0 Combustion unit
- 38 x 38 cm (15 x 15 in) combustor area
- 20.3 cm (8 in) refractory
2-1
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ro
i
ro
GENCRM. ARRANGEMENT
TEST «fc
Figure 2-1. General arrangement drawing.
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ro
GENERAL ARRANGEMENT
F.B.C TEST wo
Figure 2-2. General arrangement drawing.
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fertSni... .. ...!..*..
GENERAL ARRANGEMENT
F BC TEST ME
I »- T
Figure 2-3. General arrangement drawing.
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rvs
01
ARRANGEMENT
F8 C TfST RIG
Figure 2-4. General arrangement drawing.
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- 3.05 m (10 foot) freeboard
- 122 cm (48 in) bed height
- Perforated plate distributor
- Ash removal through distributor plate
- Automatic bed height control
Air system
- Spencer blower 7080 sdm3/min, 93°C, 34.5 kPa
(250 scfm, 200°F, 5 psi), low noise
96 kW preheater
FGR mixing chamber
Staged combustion capability
Coal, sorbent and ash feed system
8 hour service bins (three)
- Vibratory feedrate controllers
- Pneumatic injection
Bin weight monitors
Primary cyclone
Refractory lined
- Nominal collection size 7y at facility design point
Secondary cyclone
- Aerodyne "tornado" cyclone
- Externally insulated stainless steel 310
ESP
Double chamber design
- Temperature rating to 260°C (500°F)
Baghouse
- Reverse pulse
2-6
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- 6.8 m2 (73 ft2) teflon felt material
- Temperature rating to 260°C (500°F)
Flue gas heat exchangers
- Refractory-lined housing
- Water-cooled cooling modules
- Bare tube design
- First two modules with double pitch to prevent clogging by
flyash
- Manual soot blowing lance
0 Control system
- Manual control
- Safety interlocks
Alarm lights
- Automatic heater temperature control
- Pressure and temperature readouts
- Weight readouts
The FBC test rig is designed to take full advantage of the available
space. The 122 cm (4 foot) bed height and the 3.05 m (10 foot) freeboard are the
maximum that could be accommodated below the false ceiling in the EPA Wing G
Laboratory. The components of the rig are placed to allow access to the
combustor and other heavy parts by forklift for servicing or for a con-
figuration change. All major components are placed along the mezzanine.
By placing the flue gas ducting along the mezzanine, the design allows
sampling from that floor without requiring inconvenient, costly, and dan-
gerously high platforms.
In addition, the unit is designed to be used with all or only some
of the components onstream. Provisions have been made to enable the opera-
tor to bypass or change the flow through the secondary cyclone by adjusting
three damper valves to the appropriate positions. The secondary control
devices can also be evaluated in parallel, series, or separately by
2-7
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connecting them 1n the desired configuration with flexible ducting. Four
exit ports are provided on the flue gas heat exchanger to connect secondary
control devices. The stack Is equipped with several equipment ports and
sampling ports to gain this versatility.
The baghouse has been designed to be placed on rollers to enable the
operator to clear the central area quickly should access from the outside
be required. This would normally not be the case while the facility 1s
operating. Access by forkllft Is only required for configuration changes
and servicing of the feed bins; both of these activities can be accomplished
by entering the area from the other side.
All components of the FBC test rig have been designed to reduce the
Tabor and minimize the chance of injury to the operator. Controls and ser-
viced components are easily accessible, and all high-temperature surfaces
are insulated to reduce heat loss and make them safe for personnel.
2.2 COMBUSTOR
The major component in the FBC test rig is the combustor. As shown
in Figure 2-5, it consists of the following elements:
Combustor section
Freeboard chamber
Distributor plate
0 Heat exchangers
Air plenum box
Bed height and temperature sensors
Sampling and view ports
Injection ports
Ash removal system
Combustor Section
The combustor section houses the fluidized bed during operation. The
combustor shell measures 91.5 cm (36 inches) wide, 79 cm (31 inches) deep, and
152 on (60 inches) high. The shell is lined with mineral wool and refractory
of minimum 20 cm (8 inch) thickness. The refractory used is Harbison Walker
2-8
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Figure 2-5. Corribustor.
2-9
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40-64. It features a maximum operating temperature of 1430°C (2600°F)» low
iron oxide content and a small linear change of -0.2 to -0.6 percent at 815°C
(1500°F). The shell has been designed to permit the casting of different com-
22 7
bustor cross sections. The principal sizes are 968 cm , 1451 cm, and 1935 cm
22 ?
(150 in , 225 in , and 300 in'). These sizes are optimum for the noted heat
release rate of the combustor. Rectangular openings in two opposing sides
allow the installation of either heat exchangers or sight, sampling or injec-
tion ports. The third side contains ports for pressure and temperature measure-
ment instrument installations. Sizes and locations of the ports are noted on
the respective facility drawings.
Freeboard Chamber
The freeboard chamber consists of the upper two sections of the com-
bustor. The modules are constructed similarly to the combustion chamber but
consist of a 152 cm (60 inch) and 122 cm (48-inch high module with 1935 cm
2
(300 in ) cross sectional area. The cross sectional area of the freeboard
chamber was chosen in anticipation of the largest combustor cross sectional
areas to be used. This will reduce particulate carryover due to lower free-
board gas velocities. The modules are carbon steel, mineral wool insulated
and refractory lined. The top module is referred to as the exit module and
the lower freeboard module as the intermediate module.
With the exception of its large cross-sectional area and its lack
of a solids injection port, the intermediate module is identical to the
combustor section. This configuration allows for the insertion of free-
board heat exchangers which will be installed to maintain the gas tempera-
tures within the specified limits if a high portion of the combustion takes
place in the freeboard due to staged combustion. More importantly, the
configuration allows for the installation of staged combustion air ports and
sight and sampling ports. Not all openings are effectively usable because
of the location of the mezzanine floor and structural steel. The exit mod-
ule, otherwise similar in construction, has no rectangular access ports for
service modules; however, it is equipped with the 15 cm (6 inch) exit ports
for the mounting of flue gas ducting or particulate control devices. The top
of the module is covered with a refractory-lined lid.
2-10
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Distributor Plates
To simulate full-scale facilities and to fluidize the bed properly,
a distributor plate must have a pressure drop of approximately 30 percent of
the bed weight. For this combustor, it is in the range of 0.98 to 3.92 kPa
(4 to 16 inches) of water. To allow for the wide variation in operating con-
ditions from 1133 sdm3/min at 21°C (40 scfm at 70°F) to 7080 sdm3/min at
427°C (250 scfm at 800°F), six to seven plates are required. This number
allows for some overlap, and covers the entire range but does not represent
optimum design for all operating conditions in this range. A perforated plate
design has been selected for this combustor to accommodate the flow range at
an economical cost. The plates are made of stainless steel 310 for tempera-
ture and corrosion resistance, reinforced by 0.82 cm (1/8 inch) by 1.27 cm
(1/2 inch) flat stock ribs to reduce warpage. The edges of the plates
have been slotted to reduce the thermal stresses introduced due to tempera-
ture gradients in the plate. The plate when mounted is "floating" in its
seal, again reducing internal stresses. Since the plate is only slightly
larger than the cross-section of the maximum bed, it will attain a fairly
uniform temperature which also helps to minimize distortion.
Heat Exchangers
The combustion zone heat exchangers are bare tube and water-cooled.
To accommodate the large turndown requirement, heat exchanger modules can
be independently added and removed to attain the cooling requirement for
the required mode of operation.
The heat exchangers consist of a plenum, an insulating cover, and
hairpin cooling tubes. The tubes and the insulating cover are manufactured
from SS 310 and the cooling plenum from low carbon steel. Because a re-
fractory plug would have been too sensitive to cracking, the insulating
cover forms the sidewall of the fluidized bed when the heat exchanger is
installed. The sidewalls of the cover are made of RA 330 expanded metal to
minimize the transfer of energy to the outside wall of the FBC. The cool-
ing tubes may be operated without coolant, particularly during startup when
all the energy available should be used to bring the facility up to tem-
perature (up to 871°C (1600°F)). The heat exchangers are vented if no flow
is passing through them.
2-11
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Air Plenum Box
The air plenum box serves as the retainer for the distributor plate,
guides the air through the plate and holds the standpipe for the ash removal
system. The box is designed so that it can be easily removed. Although
blanket insulation is used rather than refractory lining in order to keep
the weight of the box down, it is still heavy and requires some support
(e.g., a forklift) for servicing. The air pipe connected to the plenum box
is mounted on a flexible line and misalignment problems have been minimized.
The inner chamber is made of stainless steel 304, and the outside shell is
carbon steel.
Bed Height and Temperature Sensors
The bed height is measured via three pressure ports by two differential
pressure measurements. One measurement will give the indication of bed
density and the other of bed height.
Two temperature probes are provided in the bed and two in the free-
board. Additional thermocouples can be added if desired.
Sampling and View Port
The combustor and the intermediate section both have rectangular
openings for the mounting of heat exchangers, sampling, view or injection
ports. As described above in the discussion of heat exchangers, view or
sampling ports are mounted on carbon steel plates equipped with a cover to
form the wall of the bed section or the freeboard. Purge air is provided
to keep these ports free of combustion materials.
Injection Ports
Solids injection is accomplished pneumatically. A special entry port
has been designed for the inlet pipe to allow the injection of materials
close to the distributor plate. If it becomes desirable to change the loca-
tion of this port, a special injection port could be built to be installed
in a heat exchanger slot. The material of construction for the injection
tube is stainless steel 310.
2-12
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A second type of port has been designed and is standard for the
staged combustion system with various configurations to satisfy the require-
ments of tangential and center injection. Very substantial injection
velocities can be achieved with these ports if as much as 30 percent of the
air is injected at one location by one tube, resulting in very high imping-
ing rates on the opposite side in the combustor. Since these high impinging
rates cause local hot spots and wear, it is recommended that the injection
rates at any one location be kept low to minimize this problem.
Ash Removal System
The ash removal system consists of a 5 cm (2 inch) diameter pipe that
extends through the distributor plate and is held in place by the plenum box.
An air operated slide gate valve is operated when the bed height exceeds a
preset upper limit initiating a sequence and sounding an alarm of 0 to 5
seconds duration. The valve is opened for 0 to 10 seconds and the actuation
is limited to once every 6 to 60 minutes. The ash is discharged into an open
container that can accommodate the material from an 8-hour full load test run.
The operation of the valve is automatic, with manual override. After the test
run, the bin should be emptied to insure the proper operation on the next
succeeding test.
2.3 AIR SYSTEM
The air system supplies the fluidized bed combustor with combustion air.
In order to burn 10 to 50 kg/hr (22 to 110 Ibs/hr) coal as planned, 1133 to
7080 sdm /min (40 to 250 scfm) of combustion air is required. The system is
capable of heating the air to 427°C (800°F) during startup to preheat the sys-
tem and ignite the coal. High excess air conditions also require preheated
air to maintain combustion temperatures. With flue gas recirculation, up to
25 percent of combustion products may be recirculated.
For staged combustion, the air system is also designed to allow air
injection in various locations above the distributor plate.
Figure 2-6 shows the schematic of the air system.
As shown in the flow diagram, air enters the system through a filter/
silencer and passes through a throttling valve. This valve is normally
open, but can be used to establish a vacuum condition to draw flue gases
2-13
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ro
i
0-538"C
(0-1,000»F)
5 cm (2")
FGR frw
suck
To c«ri>ustor
Figure 2-6. A1r system schematic.
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into the mixing chamber when flue gas recirculation is utilized. The air
passes then through the mixing chamber and mist eliminator and is metered
for total flow. The inlet valve upstream of the blower is used to regulate
the total flowrate. This valve has been placed upstream of the blower to
reduce blower surge in low flow conditions. The air is then passed through
the blower and the preheater and into the air distribution network. Staged
air is metered in each branch.
As the schematic shows, it is possible to draw only flue gases into
the blower by closing the throttling valve. This will initiate a fault
condition due to overtemperature. Under normal conditions the inlet tem-
perature should not exceed 93°C (200°F). It has been verified that no con-
densation of SO components will occur at the concentrations expected and no
damage to the blower will result.
A number of safety interlocks have been provided in the air system.
These interlocks are discussed in greater detail in the controls section.
The specifications of the major air system components are as follows:
Control Valves
V-orifice for good flow control at low flowrates
5 cm (2 inch) and 10 cm (4 inch) valves
Blower
Spencer turbine 5010-H
7080 sdm3/min at 34.5 kPa (250 scfm at 5 psi) pressure, low noise
93°C (200°F) inlet temperature
15-hp motor, 480 V, 30, 60 cycle
Orifices
Maximum pressure drop at rated flow: 2.49 kPa (10 inch) H20
Heater
96-kW duct type design
34.5 kPa (5 psi) airtight
2-15
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SCR control with over-temperature shutoff (815°C (1500°F))
480 V/30
Magnetic contact Isolation
The air system utilizes a low-noise Spencer turbine blower, a high
reliability device.
2.4 SOLID FEED SYSTEM
2.4.1 Introduction
The solids feed system meets the following requirements:
t Coal feedrate - 10 to 50 kg/hr (22 to 110 Ibs/hr)
Sorbent feedrate - 0 to 22 kg/hr (0 to 50 Ibs/hr)
a Ash feedrate - 0 to 10 kg/hr (0 to 22 Ibs/hr)
Air injection flowrate - less than 15 percent (by weight) of
total combustion air
Continuous operation
Solids particle diameter - 0.63 cm (1/4 inch)
t Pressure at injection point - nominal 117 kPa (17 psia)
The system is shown in Figures 2-7 and 2-8. The major components
are:
a Solid feed bins (three) for 8-hour service
a Support frame
a Load cells and readouts on the control console
a Vibratory feeders (3)
a Pressure controlled mixing chamber
a Jet ejector
a Pneumatic transport line
a Service air compressor
a Various gauges and regulators
2-16
-------
Figure 2-7. Solids feed system.
-------
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Figure 2-3. Solids feed system.
-------
Following is a discussion of the injection mechanism methodology.
The coal, sorbent, and flyash is stored in three 8-hour service bins,
from which it passes through downspouts onto the base of three vibrating
feeders. The feedrate of each feeder can be adjusted at the control console
by varying the voltage applied. The mouth of each feeder delivers the
materials into a common mixing hopper. The mixing hopper and the vibrating
feeders are enclosed in a housing that may be pressurized, if necessary, at
high flowrates and pressures. The common hopper guides the materials
through a jet ejector that accelerates the particles toward the combustor
for injection. A number of gauges, regulators, and valves allows proper
adjustment of injection air flowrates.
The bins are supported by load cells that deliver an analog signal
to the control console, where a direct readout indicates the respective bin
levels. This output can be converted into solids flowrates and gives an
accurate indication of mass flowrate. This direct reading method has the
advantage of giving accurate results for different materials.
The transport line has been sized to permit flow without saltation over
the specified range of solids loading. For a single 2.5 cm (1 inch) inner dia-
meter transport line, using 10 percent of the total combustion gas, it is pos-
sible to convey from 16 to 81.5 kg/hr (35 to 180 Ibs/hr) of coal/sorbent/ash
without saltation (50y to 0.32 cm (1/8 inch)). Theoretically, at transport
velocities greater than the saltation velocity, all solids will be transported.
As the transport velocity falls below the saltation velocity, solids begin to
drop out of the airstream to roll and slide along the bottom of the transport tube.
In this system, saltation is a problem only if it leads to plugging of the
line or excessive pressure fluctuations. If this occurs, a 50 percent increase in
transport air flow (or 15 percent of the total combustion gas) will eliminate any
saltation in this particle size range. If this alternative proves unattractive,
a 1.9 cm (3/4 inch) diameter transport line can be used instead of the 2.5 cm
(1 inch) line. This will provide solids flow capability down to 11.3 kg/hr
(25 Ibs/hr) with 10 percent air flow. Nearly twice the transport velocity, or
four times the pressure drop, is required. Maximum transport velocities for the
2-19
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2.5 cm (1 inch) line would be 30.5 mps (100 fps), using about 906 sdm3/min
(32 scfm) of air.
The soltds feed system consists of subsystems accomplishing storage,
metering, mixing, and pneumatic transport of coal, sorbent, and flyash to
the FBC. Controls and instrumentation are included to assure constant flow
and easy regulation of solids feedrate and air flow to the combustor.
Detailed descriptions of the individual components are given in the
following subsections.
2.4.2 Storage Bins
Each bin has been sized to allow more than 8 hours supply of material
at maximum feedrate.
The 60° cone-bottom, cylindrical bins are each suspended at two
points just below the top flange. One of the supports is a radiused load-
cell, and the other (on the opposite side of the bin) is a Vlier pivot
mount. Horizontal constraint is provided by a rubber restraining grommet
located below and at 90° to the pivot line.
Each bin is sealed to a common "mixing box" below by a 7.6 cm (3 inch)
rubber sleeve. Each bin is also sealed at the top with a gasketed lid.
An adjustable feed nozzle at the outlet of each bin provides cross-
flow regulation. Adjustment of these nozzles is addressed in Section 3.
2.4.3 Feeders
The solids feedrates are individually controlled with three specially
modified Eriez Model ISA vibratory feeders. By regulating the input voltage
of each feeder (through individual auto transformers), the vibration ampli-
tude of each feeder tray is controlled, and hence, the feedrate of each
solid.
Each feeder has been modified to prevent particle size segregation
due to vibration, and to control the amount of solids on the tray (which is
important for uniformity of flow). Because of differences in particle size
distribution, and other dust characteristics (density, sphericity, etc.),
2-20
-------
the flyash feeder requires a slightly different tray design than the coal
and sorbent feeders.
2.4.4 Loadcells
BLH Electronics Type C2M1 strain gage loadcells are used as the
primary measurement of individual solids feedrate. Each bin is supported
(on one side only) by a loadcell of the appropriate range, a 900 kg (2000 Ib)
model for the coal bin, a 450 kg (1000 Ib) model for the sorbent bin, and a
225 kg (500 Ib) model for the flyash bin.
As mentioned, each loadcell supports only half the total bin weight.
But, because each loadcell circuit has a span adjustment, each has been
adjusted to read actual total weight (in Ibs.). Also, through an adjust-
able zero level, the weight of an empty bin can be set to be zero (or some
other convenient number if zero is out of range).
There are several possible sources of error in the loadcell reading
that can be avoided through proper action. Because only one loadcell is
used, it is important to load the bin evenly to distribute the weight
equally. Secondly, the loadcell reading has a slight dependence on bin
pressure, hence, a change in air flow can affect weight readings if con-
stant bin pressure is not maintained. These and other possible sources of
error in weight readings are discussed further in Section 3.
2.4.5 Vibrators
To assure smooth and continuous flow of solids to the feeder
(especially at low bin levels), and to prevent "ratholes and bridges" in
each of the materials, it is necessary to provide external agitation. For
this purpose, the bins are equipped with Vibco Model VS-130 turbine
vibrators. Both the coal and sorbent are fairly easy to handle solids and
therefore need only one vibrator each. The vibrator is located on the cone
section of the bin and is used primarily at near-empty conditions.
The flyash, however, being less dense, smaller, and stickier has a
vibrator mounted on the outlet downcomer in addition to one on the cone.
2-21
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Controls exist to vary the inlet pressure to all vibrators and to
vary the duty cycle of each vibrator. They are discussed in the controls
section.
2.4.6 Pressure Relief
The solids feed system comes equipped with two, redundant Circle-seal
model 559 pressure relief valves.
Without pressure relief, if the transport tube clogged, the bin would
be quickly pressurized to the ejector supply pressure - as high as 689 kPa
(100 psi). Obviously, the bins and mixing box are not designed to withstand
this pressure. The relief valves will insure that the bin pressure does not
exceed a preset level.
For adjustment instructions, see Section 3 and the manufacturer's
instructions.
2.5 GAS CLEANUP SYSTEM
The gas cleanup system can be divided into two categories: high-
temperature devices and low-temperature devices. The high-temperature
devices are the primary and secondary (or "tornado") cyclones (540°C to 1080°C)
(1000°F to 2000°F). The low-temperature devices are the electrostatic pre-
cipitator (ESP) and the baghouse (149°C to 260°C) (300°F to 500°F). Each of
these is discussed in further detail in the following subsections.
Other kinds of cleanup devices can easily be evaluated by rerouting
the ducting or bolting the devices in place of the installed equipment.
The low-temperature systems can be particularly easily adapted with flexible
hoses.
2.5.1 Primary Cyclones
Experience with FBC units has shown that a small portion (^10 per-
cent) of the coal carbon is not combusted during the first combustion cycle.
These unburned materials are usually collected in vertical separators or
cyclones and recycled to the combustor or fed into special burnup cells for
combustion.
2-22
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The primary cyclone collector has been designed to have a cut size
of 7y at the typical operating condition of 18,400 adm /min (650 acfm).
Since this facility will be used over a wide range of operating con-
ditions, some of the components have been oversized. This is particularly
true of the blower. A higher than normal pressure drop in the cyclone can
thereby be tolerated. Higher pressure drops or velocities through a cyclone
also imply smaller cut sizes - a desirable feature. The cyclone has, there-
fore, been slightly undersized for the design point, in order to allow col-
lection of materials at low flowrates. Higher pressure drops (to a maximum
pressure drop of 2.49 kPa (10 inches H20) at higher operating flowrates must
be accepted. The cyclone must also operate at elevated temperatures.
Two methods of construction were considered for the primary cyclone:
(1) Hastelloy X lined construction with high-temperature insulation on the
outside, and (2) refractory-lined construction of carbon steel. The
refractory-lined carbon steel shell construction was selected because refrac-
tory is not as sensitive to corrosion or limited to a maximum operating con-
dition of 1080°C (2000°F). Some pilot scale facilities have also experienced
fires in the cyclones during upset conditions and this was considered in the
design.
2.5.2 Tornado Cyclone
For the collection of particles not captured by the primary cyclone,
a tornado-type cyclone is provided and placed in series with and immediately
downstream of the primary cyclone. Gas flow from the primary cyclone can
be directed through the tornado device.
The unit installed is an Aerodyne Model 400SV dust collector. It is
reported to have greater collection efficiencies for small particles than
conventionally designed cyclones due to the increased vorticity within the
cyclone body. This added swirl results from the provision of a secondary
airstream directed in such a way as to increase the tangential velocity of
the flow within the cyclone body.
The unit is constructed from SS 310 and is externally insulated with
a ceramic fiber felt for heat retention and personnel safety. For this unit
2-23
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to operate properly, the pressure drop between the secondary inlet and outlet
duct must be adjusted by dampers during operation. The pressure drop must be
on the order of 30.5 kPa (12 inches H,0). At this pressure drop, the flowrate
3
in the secondary leg is 7530 adm /min (266 acfm). The primary flow can then
be adjusted to make up for the difference in flow, to a maximum of 11,330
adm /min (400 acfm). A portion of the flow may be bypassed should the
capacity of the unit be exceeded.
2.5.3 Electrostatic Precipitator
The combustion gases are initially cleaned by the two inertial col-
lectors immediately downstream of the FBC. The gas is then cooled, in order to
allow for the use of commercially available electrostatic precipitators (ESP)
and fabric filters (baghouse). Several full-scale industrial ESP's have been
operated at temperatures of about 427°C (800°F). Temperature limits for
fabric filters, however, are established by the temperature limits of the
filter materials now available. Teflon, fiberglass, and Nomex are recog-
nized to be state-of-the-art high-temperature filter materials. Their
maximum allowable temperature limit is in the range of 232°C to 260°C (450°F
to 500°F). In order to provide a cost-effective solution to the need for
evaluating both ESP and filter technology, the gas will be cooled to approx-
imately 260°C (500°F) by using the flue gas heat exchanger.
Full-scale industrial electrostatic precipitators are of the single-
stage design. A two-stage design was, however, the only design available in
the size required for this project (11,300 adm /min at 260°C) (400 acfm at
500°F). The design point represents the nominal midpoint in the flow range for
the FBC. This value has also been used in the selection of the baghouse. On
the average, efficiency will increase for lower flow and will decrease for
higher flow values.
ESP's in the 11,330 to 14,200 adm /min (400 to 500 acfm) size range are
typically designed for cleaning air circulating through heating and air-
conditioning systems or for cleaning the effluent from grease cookers. Due to
cost, weight and ease of fabrication, aluminum is generally used in constructing
ESP's of this kind. Aluminum, however, is not acceptable for the 260°C (500°F)
inlet condition specified above. Therefore, a special design using 304 SS was
selected for this project. The unit was fabricated by Beltran Associates using
2-24
-------
o
their standard design dimensions for a 11,330 adm /min (400 acfm) unit. The
unit consumes less than 100 watts of power and collects 70 to 95 percent of
the particles that are not collected by the upstream collectors. (Ninety
percent of the particle sizes passing through these inertia! devices are pre-
dicted to be less than 2 um; achieving high overall collection efficiencies
is made difficult by these smaller particles.)
2.5.4 Baghouse
In order to evaluate the compatibility of available fabric filtration
technology with the combustion products generated by an FBC, a fabric filter
(baghouse) was installed in series with the ESP. Although the inlet grain
loading and the mass median diameter of incoming particles is significantly
reduced (approximately 0.023 gm/fm (0.01 grains/scf) and 0.8 to 0.9 um), the
provision of this unit allows for the evaluation of filtration devices on
FBC effluents.
o
Commercially available baghouses in the 11,330 adm /min (400 acfm) range
offer any of the following techniques for cleaning the accumulated dust cake
from the filter surface:
Reverse flow
t Mechanical shake
Reverse pulse
Multiple units would be required for either of the first two mechanisms due
to the need for removing the filter from the process during fabric cleanup.
Moreover, the gradually increasing pressure drop followed by a sudden drop
(as one unit is taken off stream and another is put back online) is undesir-
able for the air system being designed.
The reverse pulse technique of fabric cleaning is not burdened with
either of these limitations. The reverse pulsing technique is accomplished
by rapidly pulsing (^0.1 sec) the tubular bags with compressed air. The
shock wave, as it travels the length of the filter, dislodges the accumu-
lated dust cake. The interval between pulsing is usually determined by the
inlet grain loading, and is preprogrammed so that the pulsing of various
bags is continuous.
2-25
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A reverse pulse unit with a virtually static pressure differential
has been procured for this program. The unit is a Young Industries
vertical/modular "UniCage" filter collector, Model Number VM 42-16. The
design of this unit allows for the easy replacement of the filter tubes for
the evaluation of various high-temperature fabrics. The VM 42-16 is constructed
p
of carbon steel and contains 6.78 m (73 square feet) of teflon felt. The unit
requires 57 sdm3/min (2 scfm) of dry, oil-free air at 620 kPa (90 psig) for
the reverse pulse cleaning.
2.6 FLUE GAS HEAT EXCHANGERS AND SOOT BLOWING LANCE
The flue gas heat exchanger cools the high-temperature exhaust gases
from up to 1094°C (2000°F) to approximately 204°C (400°F). At this temperature,
no condensation will occur in the ESP or baghouse. Thus, severe corrosion will
be avoided. The flowrate is 1133 to 7080 sdm3/min (40 to 250 scfm) and the
heat transfer requirement is 42,400 kJ (40,000 Btu/hr) to 594,000 kJ
(560,000 Btu/hr).
The heat exchanger installed (Figure 2-9) consists of a refractory-
lined carbon steel shell. Ten bare tube heat exchangers provide the large
turndown required. During operation, only those units required for cooling are
turned on. All other units are connected to a drain. The tubes themselves
are made out of 1.6 cm (5/8-inch) outer diameter SS 304 tubing mounted in
carbon steel plenums.
Experience with the heat exchangers in multifuel furnaces has shown
that considerable solid material can collect on the tubes. This calls for
wider spacing of the first heat exchanger tubes than of the later tubes. To
clean the tubes without requiring the removal of the heat exchangers, a soot
blowing lance (Figure 2-10) has been provided. The lance can be used to
clean the tubes while the unit is in operation. Entry ports for the probe
have also been provided. Through these, the probe can be inserted and an
air spray jet be directed onto the tubes. The soot material falls to the
bottom of the heat exchanger, where it is collected in an ash drawer that
can be easily removed and emptied.
2-26
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Figure 2-9. Flue gas heat exchanger.
2-27
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Figure 2-10. Soot blowing lance.
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2.7 CONTROL SYSTEM
2.7.1 Introduction
The controls and instrumentation of the FBC test rig serve four basic
subsystems:
Fluidization air supply system
0 Coal/sorbent storage and transport system
0 Fluidized-bed combustion unit
§ Flue gas cleanup system
Each of these subsystems has distinct measurement capabilities which
are equipped with special alarms or interlocks. These alarm systems have
adjustable set-points and are interlocked with the process safety and inter-
lock system.
Three of the above systems are essentially always used in a similar
configuration and represent the heart of the FBC. The flue gas cleanup sys-
tem, however, will be arranged into many different configurations to suit the
needs of the test. These devices are also relatively passive and require
little control. The philosophy followed here is to provide "plug in" capa-
bility to measure the desired temperatures and pressures, and to provide the
required alarm capability.
Fluidization Air Supply System
The fluidization air input to the combustor is controlled by separately
controlling the total air flowrate and the flue gas recirculation (FGR) rate.
Each of these is controlled by the operation of manual valves. The total
fluidization air flowrate and the FGR flowrate are derived by measuring the
differential pressure across orifices. The absolute pressure and temperature
are measured for mass flowrate computations. The amount of excess air is
measured indirectly by measuring the oxygen content in the flue gas. The
excess air is controlled by adjusting the ratio of ambient air to flue gas.
2-29
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Coal/Sorbent Storage and Transport System
The coal, sorbent, and ash feedrates are controlled by manually ad-
justing a variac controller on the control console. The voltage variation
in turn causes a more or less severe vibration of the vibratory feeders.
Direct-reading mass transducers give indications of the various amounts of
materials being fed into the FBC.
When coal, sorbent, or ash is fed, the pneumatic transport air is
controlled by manual valves and measured by means of a laminar flow element
in the line. As before, absolute pressure and temperature are measured for
mass flowrate computations.
Each supply bin is equipped with a status alarm to indicate a low
supply. Because of the abrasive nature of coal, erosion of pneumatic trans-
port lines can cause problems. These have been minimized by design.
Fluidized-Bed Combustion Unit
Temperature in the fluidized bed combustion unit is measured at
multiple locations within the bed and the freeboard. Although any one of the
temperatures could be controlled, only bed temperature is controlled. This
is done by controlling the water flowrate in the cooling coils and by adding
or removing heat exchanger surface area. Cooling water flowrate and inlet/
outlet temperatures are measured for energy balance computations. The bed
height can be controlled by installing an overflow port at the appropriate
location. Ash can be removed automatically through the removal tube to main-
tain the bed height within a certain height tolerance band. Bed height is
measured by noting the pressure differential between three known points -
two in the bed region and one in the freeboard. In the same way, bed density
is measured by reading the pressure differential between two points a known
distance apart within the bed, and the bed height in proportion to a third
point. Other pressures measured are inlet pressure, freeboard pressure, and
distributor pressure differential.
Safety interlocks include low air velocity, bed overtemperature and
heat exchanger overtemperature.
2-30
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Flue Gas Cleanup System
For each cleanup device, three measurements are made;
t Pressure differential inlet/outlet
Inlet pressure
Inlet temperature
Of these, only the first inlet temperature after the chiller is controllable.
This control is achieved by adjusting the water flowrate in one or more of
the chiller banks, using manual valves. The inlet and outlet bulk tempera-
tures on each bank are measured. To provide the required flexibility, out-
let boxes for the measurement umbilicals are provided near these devices.
This allows the setup in any required configuration.
Safety interlocks include a cleanup device inlet overtemperature
warning light and a high differential pressure warning. Figure 2-11 shows
the system P&ID.
2.7.2 Control Systems - Panels
The control system is divided into four major sections corresponding
to the functional systems (see Figure 2-12).
t Air supply system instrumentation
t Coal/sorbent storage and transport'system instrumentation
t Fluidized-bed combustion unit instrumentation
Flue gas cleanup system instrumentation
The controls and meters are on standard 48.2 cm (19 inch) panels mounted
in vertical twin rack assemblies which are bolted together. Each panel is
assigned to a specific subsystem, thus simplifying console operation and
providing minimum disruption if maintenance or modification is required on a
given subsystem.
2-31
-------
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Figure 2-11. P&ID.
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2-33
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Measurement Methods
Process Variables - Pressure
Pressure measurements in all areas of the FBC are made using magne-
helic pressure gauges. These gauges have proven their accuracy and economy
in many applications.
Process Variables - Temperature
Temperature measurements within the system are designed to be within
the range of 0 to 1204°C (0°F to 2200°F) in an oxidizing atmosphere. Acurex
has selected ISA Type K thermocouples in a closed tip stainless steel sheath
for these measurements.
2.7.2.1 Air Supply System Instrumentation
The air system provides the primary and secondary air at a con-
trolled temperature and flowrate to the combustion chamber. Flue gas re-
circulation of up to 25 percent is also possible. The primary air supply
system consists of manual flow control valves, flow measurement devices, the
blower, heater and controllers. The secondary air system provides air for
staged combustion at desired flowrates to three combustor locations. The
flow is controlled by manual valves and flowrates are indicated indirectly
by pressure and temperature measurements. The same control philosophy ap-
plies to the flue gas recirculation loop. Table 2-1 lists the measurements,
ranges and identification numbers for the air system. Controls located on
the air system panel are the:
Blower power controls
Heater power controls
Heater controllers
Temperature sensing selector switch and
Heater lights for the blower, heater, blower inlet temperature,
heater overtemperature and air flowrate.
Two temperature controllers are provided to control the air preheat tempera-
ture and protect the heater from sheath overtemperature. The heater was
2-34
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TABLE 2-1. AIR SUPPLY SYSTEM INSTRUMENTATION
Measurement
FGR & air mixing
screen diff. pr.
Main orifice inlet pr.
Main orifice diff. pr.
Main orifice inlet temp.
Blower trip temp.
FGR inlet pressure
FGR orifice diff. pr.
FGR inlet temperature
Low air velocity switch
Air heater sheath temp.
Air heater outlet temp.
Secondary air inlet pr.
Secondary air LEG I
orifice diff. pressure
Secondary air LEG I
inlet temperature
Secondary air LEG II
orifice diff. pressure
Secondary air LEG II
inlet temperature
Secondary air LEG III
orifice diff. pressure
Secondary air LEG III
inlet temperature
Range
0-1.25 kPa
(0.5" H20)
0-5 kPa
(0-20" H20)
0-2.5 kPa
(0-10" H20)
0-93°C
(0-200°F)
93°C
(200°F)
0-2.5 kPa
(0-10" H20)
0-2.5 kPa
(0-10" H20)
0-316°C
(32°F-600°F)
0-0.125 kPa
(0-0.5" H20)
0-871 °C
(0-1600°F)
0-649°C
(0-1200°F)
0-37.3 kPa
(0-150" H20)
0-25 kPa
(0-10" H20)
38-538°C
(100-1000°F)
0-2.5 kPa
(0-10" H20)
38-538°C
(100-1000°F)
0-2.5 kPa
(0-10" H20)
38-538°C
(100-1000°F)
P&ID Identification
7255-101D
DPI-100
PI-100
DPI-101
TE-100/TI-100-1
PI-105
DPI-108
TE-115/TI-100-2
DPS- 100
TE-101/TY-101
TE-102/TIC-102
PI-102
DPI-102
TE-103/TI-102-2
DPI-103
TE-104/TI-102-3
DPI-104
TE-105/TI-102-4
P&ID Loc.
7255-101 D
D-7
D-7
D-7
D-7
A-4
A-4
A- 3
D-6
D-6
D-6
C-6
C-6
C-6
C-6
C-6
C-6
C-6
2-35
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designed to deliver up to 427°C (800°F) air to the combustor. This requirement
dictates slightly higher temperatures at the heater outlet of approximately
454°C (850°F). The sheath temperature must not exceed 871°C (1600°F) and in
order to insure that this does not occur, should be controlled to a maximum
of 815°C (1500°F) at the sensing location. Tests have verified that 538°C
(1000°F) heater outlet temperatures are safely achievable.
2.7.2.2 Solids Feed System Instrumentation
The solids feed system controls are divided into two sections. All
pneumatic controls are located on the solids feed frame control panel,
whereas electrical controls and interlocks are located on the main control
panel. Figure 2-13 clearly identifies those controls located on the solids
feed system and those located on the main control console.
There are two panels on the main control console used in controlling
and monitoring the air and solids flow (Figure 2-14).
The air flowmeter panel is located at the top right of the console.
It shows air flowmeter inlet pressure and differential pressure across the
flowmeter.
The solids control panel is located on the lower right side. It pro-
vides the following functions:
Feeder controls on/off control only
Bin weight monitors - load cell readout and selector switch
Low bin level indicator lights
Ejector
It is advantageous, for two reasons, to be able to control the air
flowrate and bin pressure independently. First, it allows continuous load-
cell readings while varying air flowrate. Secondly, the bins can be loaded
without stopping the airflow (.by depressurizing the bins). Normally (with a
plain transport line), the bin pressure will vary with the square of the air
flowrate, and will also vary directly with the combustor inlet pressure.
2-36
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AIR FLOWMETER
INLET PRESSURE
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COAL BIN LOW
LOADCELL
SELECTOR
SWITCH
SORBENT
BIN LOW
SOLIDS
FEEDRATE
ON/OFF
CONTROLS
AIR FLOWMETER YP
LOADCELL READOUT
FLYASH BIN LOW
SOLIDS FEED OFF
BIN VIBRATOR
ON/OFF CONTROLS
SOLIDS
FEEDRATE
CONTROLLERS
Figure 2-13. Main control console -~ solids feed system panels.
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Figure 2-14. Pneumatic diagram.
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By adding an Air-Vac engineering Model TORH-750 air ejector to the
transport line, the air flowrate and bin pressure are decoupled. This can
be seen by noting that the air flow can be made up of virtually any com-
bination of Inlet air and supply air (as shown in Figure 2-15), and by not-
ing that as the supply air increases, so does the pressure rise across the
ejector. Figure 2-16 shows the map of values that the ejector can cover in
this system.
Local Control Panel
The local control console is located at the right edge of the solids
feed system structure. It is mounted on a swivel to permit viewing and
access from either the main control console or from the front of the solids
feed system.
The local pneumatic control panel, shown in Figure 2-17, provides
nearly all of the control and instrumentation to regulate and monitor the
air flow, bin pressure, and vibrator pressure. FBC inlet pressure is also
provided on the local control console.
Operation and specific function descriptions are contained in
Section 3. Table 2-2 identifies all measurements, identification and
locations for the solids feed system.
2.7.2.3 Fluidized Bed Combustion Unit Instrumentation
The active control subsystems in the FBC test rig are the air system
and the solids feed system. Although the combustion actually takes place
in the combustor, it is otherwise a rather passive element. The instru-
mentation associated with the combustor consists primarily of overtempera-
ture protection devices and temperature and pressure measurement devices.
Temperature alarms alert the operator and simultaneously shut down the
solids feed. Measurements are listed in Table 2-3. The temperature in the
bed is primarily controlled by the amount of heat exchanger surface sub-
merged in the bed and secondarily by the water flowrate. The water flow-
rate control can only achieve a 2:1 heat transfer turndown and is therefore
not viable for temperature control. The temperature is primarily controlled
through excess air and coal feed rates.
2-39
-------
AIR
INLET
AIR
SUPPLY
L_J
t
OUTLET
(TO FBC)
Figure 2-15. Air ejector nomenclature.
2-40
-------
ro
ts.
z
m
WG
50
I
~2 40-f 10.0
CO
0.
o
m
cc
o
LU
3
5
111
(A
E
cc
(O
£
10-
kPa
12.5
30- 7.5
276 kPa (40
206 kPa (30 PSI)
20- 5.0
138 kPa (20
69 kPa (10 PSI)
2.5
AP @551 kPa INLET PRESSURE
("WG @80 PSI INtET PRESSURE)
0.5 1.25 1.75
(2) (5) (7)
0 kPa
(0 PSI)
6.89 kPa
(1 PSI)
13.8 kPa
(2 PSI)
20.6 kPa
(3 PSI)
ill
cc
34.5 kPa
PSI)
48.2 kPa
PSI)
68.9 kPa
(10 PSI)
(5)
(10)
(15)
(20)
(25)
(30)
(35)
(SCFM)
0
1
100
200
300
400
I
500
I
600
700
I
800
1
900
1000
SDM3/MIN
AIR FLOW
Figure 2-16. Ejector pressure rise vs. air flow.
-------
ro
i
ro
PRIMARY
REGULATOR
PCV-118
SECONDARY
REGULATOR
PCV-119
BIN VIBRATOR
AIR SUPPLY
REGULATOR
PCV-117
TRANSPORT AND
VIBRATOR AIR
ON/OFF
V-120
PURGE AIR
REGULATOR
PCV-122
PURGE AIR
ON/OFF
V-112
s. PI-11C
X)
PI-116 PI-117 PI-113
| PI-111 PM12
o o-
PURGE AIR
FLOW CONTROL
EJECTOR
AIR SUPPLY
REGULATOR
PCV-120
EJECTOR
INLET
REGULATOR
PCV-121
BIN PRESSURE
FBC INLET
PRESSURE
Figure 2-17. Pneumatic control console.
-------
TABLE 2-2. SOLIDS FEED SYSTEM INSTRUMENTATION
Measurement
Coal feedrate
Sorbent feedrate
Ash feedrate
Bin coal weight
Bin sorbent weight
Bin ash weight
Coal bin vibrator timer
Sorbent bin vibrator
timer
Ash bin vibrator timer
Vibrator supply air pr.
Primary air supply reg.
Secondary air sply. reg.
flow element inlet pr.
Flow element air temp.
Flow element diff. pr.
Ejector supply pressure
Mixer supply pressure
Pneumatic inlet FBC pr.
Purge air
Range
0-50 kg/hr
22-110 Ibs/hr
0-22 kg/hr
0-50 Ibs/hr
0-8 kg/hr
0-20 Ibs/hr
0-906 kg/hr
0-2000 Ibs
0-453 kg/hr
0-1000 Ibs
0-226 kg/hr
0-500 Ibs
3-120 sec
3-120 sec
3-120 sec
0-1102 kPa
0-160 psi
0-1102 kPa
0-160 psi
0-1102 kPa
0-160 psi
0-93°C
32-200°F
0-7.5 kPa
0-15" H20
0-1102 kPa
0-160 psi
0-34.5 kPa
0-5 psi
0-34.5 kPa
0-5 psi
0-1102 kPa
0-160 psi
P&ID Identifica-
tion 7255-1 01 D
HRC-100
HRC-101
HRC-102
WE-100/WI-100-1
WE-101-WI-100-2
WE-102/WI-100-3
HS-113/LV-113
HS-114/LV-114
HS-115/LV-115
PI-m/PEV-117
PI-116/PEV-117
PI-117/PEV-119
FE-118/TI-100-3
DPI-113
PEV-120/PI-113
PCV-121/PI-112
PI-115
FI-100/FI-101
P&ID Loc.
7255-101D
C-7
C-7
B-7
C-8
C-8
B-8
C-8
C-8
B-8
A-8
A-8
A-8
A-7/3-7
A- 7
B-6
B-7
B-5
B-6
2-43
-------
TABLE 2-3. FLUIDIZED BED COMBUSTION UNIT INSTRUMENTATION
Measurement
Air plenum box pressure
Air plenum box temp.
AP distributor
AP bed density
AP bed height
Freeboard pressure
Bed temperature probes
Freeboard temp, probes
Heat exchanger bulk
water inlet temperature
Heat exchanger water
inlet pressure
Differential Orifice I
pressure
Differential Orifice II
pressure
Heat exchanger bulk
outlet temperature
Heat exchanger -1 outlet
temperature
n H _2 H
H II O II
"*
:: ;; -,4 :;
» -
" -10 "
Range
0-37 kPa
0-150" H20
0-538°C
32-1000°F
0-5 kPa
0-20" H20
0-7.5 kPa
0-30" H20
0-7.5 kPa
0-30" H20
0-25 kPa
0-100" H20
0-1204°C
32-2200°F
0-1204°C
32-2200° F
16-38°C
60-1 00°F
0-689 kPa
0-100 psi
0-7.5 kPa
0-30" H20
0-7.5 kPa
0-30" H20
16-100°C
60-21 2°F
Adjust to
60°C
140°F
16-100°C
60-212°F
P&ID Identification
7255-101 D
PI-103
TE-300/TI-300-1
DPI-107
DPI-107
DPI-106
PI-104
TE-301/TI-300-2
TE-305/TI-300-3
TE-302/TAH-302
TE-303/TI-300-3
TE-304/TI- 300-4
TE-200/TI-200-1
PI-200
DP 1-200
DP I -201
TE-202/TI-200-2
TE-201-A/TI-200-3
-B -4
-C -5
-D -6
1 1
-J -12
P&ID Location
7255-101D
B-5
B-4
B-5
C-5
C-5
D-5
B-4
C-4
C-4
D-4
D-4
D-6
D-5
D-5
C-5
C-4
D-4
D-4
i '
2-44
-------
The heat exchanger water supply system has been provided with a high
and low water flowrate orifice. This configuration allows for accurate
measurements and a minimum changeover service requirement. The two branches
of the water supply system can be installed and used in separate cooling
circuits such as a freeboard heat exchanger circuit and the bed heat ex-
changer circuit. Each branch flow can be monitored independently.
2.7.2.4 Flue Gas Cleanup System Instrumentation
The flue gas cleanup system instrumentation consists principally of
temperature and pressure sensors and indicating devices located on the flue
gas ducting and control console respectively. The only controls are valves
controlling the flowrate through the secondary cyclone and thereby setting
the pressure drops and the coolant control valves for the flue gas cooler.
Like the heat exchanger coolant manifold for the combustor, the coolant
manifold for the flue gas cooler has a high and low flow orifice branch to
permit accurate flow measurements to be made while accommodating a high turn-
down capability. The flue gas exhaust temperature is principally controlled
by adding and subtracting heat exchanger surface. The temperature and pres-
sure measurement capabilities of the provided flue gas cleanup system are
listed in Table 2-4.
Certain operating modes are undesirable because they may result in
equipment damage. These modes of operation are indicated to the operator by
warning lights on the control console. Undesirable operating conditions are
excess coolant water temperatures, high baghouse inlet temperatures and high
differential pressures across the baghouse.
2.7.3 Process Variables Oxygen and Combustibles Analyzer
To gain close control over the combustion process, the oxygen concen-
tration (excess air) must be monitored. A Teledyne combustion process
analyzer Moder 9700 has been provided for this purpose. The analyzer can be
divided into the oxygen and combustibles monitoring sections.
The oxygen analyzer employs an electrochemical transducer to provide
an electrical signal that is directly proportional to the oxygen concentra-
tion in the gas phase immediately adjacent to its sensing surface.
2-45
-------
TABLE 2-4. FLUE GAS CLEANUP SYSTEM INSTRUMENTATION
Measurement
Primary Cyclone
Inlet temperature
AP primary cyclone
Downspout temperature
Secondary Cyclone
Inlet temperature
Inlet static pressure
AP primary to secondary inlet
AP secondary inlet to outlet
Downspout temperature
Outlet temperature
Flue Gas Heat Exchanger
Gas inlet temperature
Flue gas cooler outlet 1
Flue gas cooler outlet 2
Heat exchanger bulk water inlet temp.
Differential Orifice I pressure
Differential Orifice II pressure
Heat exchanger bulk outlet temperature
Heat exchanger -1 outlet temperature
H * _? " "
U N 1 N M
" " -10 " "
Electrostatic Precipitator
Inlet gas temperature
Baghouse
AP inlet-outlet
Inlet gas temperature
Pulse plenum pressure
Range
0-1094°C
(32-2000°F)
0-3.8 kPa
(0-15" H20)
0-816°C
(32-1500'F)
0-927°C
(32-1700°F)
0-7.5 kPa
(0-30" H20)
0.75 kPa
(0-30" H20)
0-3.8 kPa
(0-15" H20)
0-816'C
(32-1500eF)
0-3.8 kPa
( 32-2000° F)
0-3.8 kPa
(32- 2000° F)
0-288°C
(32-550°F)
0-2888C
(32-550°F)
16-38°C
(60-100°F)
0-7.5 kPa
(0-30" H20)
0.7.5 kPa
(0-30" H20)
16-38°C
(60-212-F)
16-388C
(60-212°F)
1
0-288°C
(32-550-F)
0-2.5 kPa
(0-10" H20)
0-260°C
(32-500°F)
o-no2
(0-160 psi)
P&ID Identifica-
tion 7255-1 01 D
TE0304/TI-300-3
OPI-109
TE-109/TI-102-6
TE-107/TI-102-5
PI-106
DPI-111
DPI-110
TE-110/TI-102-8
TE-108/TI-102-7
TE-116/TI-102-9
TE-117/TI-100-4
TE-lll/TI-100-5
TE-203/TI-201-1
DPI -202
DPI-203
TE-205/TI-201-2
TE-201-A/TI-201-3
-B/TI-201-3
-J/TI-201-12
TE-113/TI-102-10
DPI-112
TE-112/TI-100-6
PI-108
P&ID Location
7255-101D
D-4
D-3
D-3
D-3
D-3
D-3
D-3
D-3
D-2
C-l
B-2
B-2
C-3
C-3
C-3
B-2
C-l
B-3
B-2
B-2
B-2
T-808
2-46
-------
One of the three available ranges of analysis is 0 to 25 percent so
that air (2.9 percent oxygen) may be used to calibrate the sensitivity of
the analyzer. It is equipped with an exceptionally accurate 12.7 cm (5 inch)
panel meter for direct readout of the analysis. An output signal of 0 to
1 V D.C. is also available.
The combustibles monitor consists of controls, readout meters, alarm
relays, sensors, flowmeters, valves and heaters. A prominent meter displays
the gas concentration at the detection point as a percentage of the com-
bustible gases and is graduated from 0 to 5 percent combustibles. An alarm
bell will sound off should the concentration exceed a predetermined value.
The complete description of the equipment, operation and service re-
quirements is given in the instruction manual for the oxygen and combustibles
system Model 9700.
2.7.4 Safety Interlocks
The following system safety interlocks are provided to reduce the
danger of failure. Attended operation, however, is required to monitor the
operation of the facility. All circuits are protected by circuit breakers
for overload conditions. The devices are listed in Table 2-5.
2.7.5 Instrument Listings
The FBC Test Rig has been instrumented with temperature, pressure and
other sensors to allow measurements to be made for purposes of safety,
energy and mass balance's trend analysis and to generate those conditions of
interest for pollution control tests. The following Tables 2-6 and 2-7 list
the instruments, their function and the location on the system P&ID. The
tables, together with the P&ID, allow for quick identification during tests.
2-47
-------
TABLE 2-5. SAFETY INTERLOCKS
Condition
High blower Inlet
temperature
Low air velocity
Bed over-temperature
Coolant overtemperature
High baghouse AP
High cleanup device
temperature
Low water pressure-bed
Low water pressure cooler
Solids level Indicator
- low -
High combustibles
Device
Temp, switch
AP switch
Temp, switch
Temp, switch
AP switch
Temp, switch
AP switch
AP switch
Transducers
Analyzer
Response
Power off/heater off/
solids off
Solids off/heater off
Solids off
Solids off
Red light
Red light
Red light
Red light
Red light
Bell
2-48
-------
TABLE 2-6. INSTRUMENT NOMENCLATURES
Identification
Temo. Element
TE-100
TE-101
TE-102
TE-103
TE-104
TE-105
TE-106
TE-107
TE-108
TE-109
TE-110
TE-111
TE-112
TE-113
TE-114
TE-115
TE-116
TE-117
TE-118
TE-200
TE-201A
B
" C
11 D
11 E
11 'F
" G
" H
I
11 J
TE-202
TE-203
TE-204A
B
11 C
11 D
" E
11 F
" G
11 H
11 I
" J
TE-205
Location
D-7
D-6
D-6
C-6
C-6
C-6
D-6
D-3
D-2
D-3
D-2
B-2
B-2
B-2
B-3
A- 3
C-2
B-2
B-7
D-6
D-4
H
M
H
ii
H
u
n
n
it
C-4
C-3
C-2
ii
u
n
u
H
n
n
ii
n
B-l
Indication
TI-100-1
TI-101
TIC-102
TI-102-2
TI-102-3
TI-102-4
TI-102-1
TI-102-5
TI-102-7
TI-102-6
TI-102-8
TI-100-5
TI-100-6
TI-102-10
TI-102-11
TI-100-2
TI-102-9
TI-100-4
TI-100-3
TI-200-1
TI-200-3
11 4
" 5
" 6
" 7
11 8
11 9
11 10
11 n
12
TI-200-2
TI-201-1
TI-201-3
11 4
11 5
" 6
" 7
11 8
11 9
11 10
11 11
12
TI-201-2
Function
Main orifice inlet
Heated sheath T. contr.
Heater air temp, contr.
Sec. air temp, leg 1
II II II II 0
II II II II 0
Main air temperature
Pr. cyclone outlet gas temp.
Sec. " " " "
Primary cyclone dipleg
Sec. cyclone dipleg
Flue gas cooler outlet 1
Baghouse inlet
ESP inlet
Stack temp.
FGR orifice inlet
Flue gas cooler inlet
Flue gas cooler outlet 2
Flow element inlet, air
temp, solid feed system
Fluid, bed exchanger water in
Fluid, bed exchanger 1 " out
ii n n y " "
II II II o " H
n ii n A ii ii
II II II C II II
II II II C II II
II II II 1 II II
II II II O II II
ii ii ii n n n
ii ii u iQ u n
bulk out
Water inlet FG cooler
Water outlet exchanger 1
II II II n
II II II -j
4
5
6
M n M y
ii H n p
M ii ii Q
" " 10
Water bulk out FG cooler
2-49
-------
TABLE 2-6. Continued
Identification
TE-300
TE-301
TE-302
TE-303
TE-304
TE-305
Temp. Switch
TS-100
TS-200
TS-201
TS-102
Flow Orifice
FO-200
FO-201
Location
B-4
B-4
C-4
D-4
D-4
C-4
D-7
C-3
B-l
B-2
C-3
C-3
Indication
TI-300-1
TI-300-2
TAH-302
TI-300-4
TI-300-5
TI-300-3
TAH-200
TAH-201
TAH-102
Function
Air plenum temperature
Fl . bed temperature I
Fl . bed overtemperature alarm
Lower freeboard temperature
Upper freeboard temperature
Fl. bed temperature II
Blower overtemperature
Water out overtemp. /light
Water out overtemp. cooler
Baghouse overtemp. alarm light
Water restr. dipleg primary
secondary
Hand Rheostat Contr
HRC-100
HRC-101
HRC-102
HS-113
HS-114
HS-115
HS-116
Pressure Indicator
PI-100
PI-102
PI-103
PI-104
PI-105
PI-106
PI-107
PI-108
PI-109
PI-110
PI-111
PI-112
PI-113
PI-114
PI-115
PI-116
PI-117
C-7
C-7
B-7
C-8
C-8
B-8
B-8
D-7
C-6
B-5
D-5
A-4
D-3
B-3
B-2
A-8
A- 7
A-8
B-7
B-6
B-7
B-5
B-7
B-7
Auto-transf. vibrators coal
. sorbent
flyash
Timer-coal bin vibrator
Timer-sorbent bin vibrator
" ash
11 ash
Main orifice inlet pressure
Sec. air plenum pressure
Plenum box pressure
Freeboard pressure
FGR-orifice inlet pressure
Sec. cyclone inlet pressure
Stack pressure
Baghouse air plenum pressure
Compressor supply pressure
Purge air pressure
Vibrator line pressure
Reg. mixing chamber pressure
Ejector pressure
Mixing chamber pressure
Injection outlet pressure
Regulator pressure
Flow element inlet pressure
2-50
-------
TABLE 2-6. Continued
Identification Location
PI-200
PS-200
PS-201
Diff. Pressure
DPI-100
DPI-101
DPI-102
DPI-103
DPI-104
DPI-105
DPI-106
DPI-107
DPI-108
DPI-109
DPI-110
DPI-111
DPI-112
DPI-113
DPI-200
DPI-201
DPI-202
DPI-203
Diff. Pres. Sys.
DPS- 100
DPSH-106
DPSL-106
DPS-107
Flow Alarm
FAL-100
Pres. Contr. Valve
PCV-117
PCV-118
PCV-119
PCV-120
PCV-121
PCV-122
PCV-123
D-5
C-3
C-3
D-7
D-7
C-6
C-6
C-6
B-5
C-5
C-5
A-4
D-3
D-3
D-3
B-2
A- 7
D-5
C-5
C-2
C-2
D-6
C-6
C-6
B-2
D-6
A-8
A- 7
A- 7
B-7
B-7
A-7
A- 7
Indication Function
Water inlet pressure
PAL-200 Low-pr; alarm light dip! eg 1
PAL-201 Low pr. alarm light dipleg 2
Mixing ch. AP
Main orifice indicator
Secondary air leg 1
H it ii p
II II II o
Distributor plate
Bed height pressure
Bed density
FGR orifice
Primary cyclone
Sec-outlet-sec, cyclone
Prim-secondary-sec, cyclone
Baghouse diff.
Flow element diff. pr.
Bed exchanger main water
sec.. "
Cooler-exchanger main water
Cooler-exchanger sec. water
Low air flow sensor
Bed height control
Bed height control
Baghouse high AP height
Low air flow light
Vibrator pressure regulator
Transport air line pr. reg.
n H H n n
Ejector pressure regulator
Mixing chamber pr. regulator
Purge air pressure regulator
Baghouse pulse pressure
2-51
-------
TABLE 2-6. Continued
Identification Location Indication Function
Pr. Safety Valve
PSV-100
PSV-101
Valve
v-m
V-112
V-113
V-114
V-115
V-120
V-121
V-204
V-205
Flow Contr. Valves
FCV-100
FCV-101
FCV-102
FCV-103
FCV-104
FCV-105
FCV-106
FCV-107
FCV-108
FCV-109
FCV-110
FCV-200
FCV-201
FCV-206
FCV-207
Selector Valve
SV-202A
" B
11 C
11 D
" E
" F
11 G
" H
" I
" J
C-7
B-7
D-8
A- 7
A-7
B-5
B-a
A-7
B-5
C-3
C-3
D-7
D-6
C-6
C-5
C-5
C-5
D-3
D-3
0-3
B-5
D-8
D-5
C-5
C-2
C-2
D-5
n
M
n
n
n
n
M
n
H
Bin pr. relief valve
Mixing chamber pr. rel valve
Mixing chamber inlet
Air supply shutoff
Air supply shutoff
Air shutoff ash valve
Ash valve
Air supply shutoff
Solids transport shutoff
Pr. dipleg water
Sec. dipleg water
Main air flow
Secondary air
Secondary air heater bypass
Secondary air leg 1
n ii n p
3
Secondary cyclone bypass dampr
11 sec. inlet
Secondary cyclone prim, inlet
Flue gas recirculation contr.
Bed exch. prim. wtr. control
" " sec. "
Cooler exchr. prim. wtr. contr
Cooler exchr. sec. wtr. contr.
Bed exchanger selector valve
n n it n
n n n ii
n n n n
n n n n
H n M n
n n n M
n M n n
n n n n
n n n n
2-52
-------
TABLE 2-6. Continued
Identification
SV-208A
" B
" C
" D
11 E
" F
" G
" H
" I
11 0
NV-203A
" B
" C
11 D
11 E
11 F
11 G
11 H
" I
" 0
NV-209A
11 B
" C
11 D
" E
11 F
11 G
11 H
11 I
" J
Solenoid Valve
SOV-113
SOV-114
SOV-115
SOV-116
SOV-117
EC-100
WE-100
WE-101
WE-102
FI-100
FI-101
Location
C-2
"
ii
11
"
"
11
11
11
"
D-A
II
II
II
II
11
II
II
II
II
C-l
n
n
n
n
n
11
n
n
M
C-8
B-8
B-8
A- 5
B-8
D-7
C-8
C-8
B-8
B-6
B-6
Indication Function
Bed exchanger selector valve
n n ii n
n n H n
n n M n
n n n n
n n n n
ii n n n
ii ii n ii
H II II II
II II II II
Bed check valves exchanger
n n n n
n n n n
n n n n
n n H n
n n n n
n n n n
n n n ii
n n n n
n n n n
Cooler check valves exchanger
n M n n
n n n M
n n n n
II M II II
n n n n
n » n n
n ii ii ii
n n n n
n n n M
Vibrator contr. solenoid val
n n n n
n n M n
ES-116 Bed height sol. contr. valve
Vibrator contr. sol. valve
Blower contactor.
ve
WI-100-1 WAL 100 coal wt. ind/alarm log
WI-100-2 WAL 101 sorbent " " "
WI-100-3 WAL 102 ash " '
Purge flow meter
n n n
2-53
-------
TABLE 2-7. TEMPERATURE SELECTOR SWITCH INDICATION
Temperature
Indicator
TI-100-1
TI-100-2
TI-100-3
FI-100-4
TI-100-5
TI-100-6
TI-102-1
2
3
4
5
6
7
8
9
10
11 11
TI-200-1
2
3
4
5
6
7
8
9
" 10
" 11
11 12
TI-201-1
2
3
4
5
6
7
8
9
11 10
11 11
11 12
Temperature
Element
TE-100
TE-115
TE-118
TE-117
TE-111
TE-112
TE-106
TE-103
TE-104
TE-105
TE-107
TE-109
TE-108
TE-110
TE-116
TE-113
TE-114
TE-200
TE-202
TE-201A
" B
11 C
" D
11 E
" F
11 G
11 H
11 I
" J
TE-203
TE-205
TE-204A
" B
11 C
11 D
11 E
" F
" G
" H
11 I
" J
Description
Main orifice inlet
FGR orifice inlet
Flow element inlet-solids feed
Flue gas cooler outlet
n H H H
Baghouse inlet
Heater air temperature
Secondary air inlet I
Secondary air inlet II
Secondary air inlet III
Primary cyclone outlet
Primary cyclone dip! eg
Secondary cyclone outlet
Secondary cyclone diplet
Flue gas cooler inlet temperature
ESP inlet temperature
Stack temperature
Fluidized bed heat exchanger water in
Fluidized bed heat exchanger water out
Heat exchanger 1 out
n n f) n
3 "
n ii ^ n
II II C II
6 "
ii n -i n
M n n 'I
n n q ii
"10 "
Flue gas cooler water inlet
Flue gas cooler water outlet
Heat exchanger 1 out
1 II O It
1 II -J I'
1 II ^ II
I 'I C H
6 "
n n -j n
8 "
n n n n
10 "
2-54
-------
SECTION 3
FACILITY OPERATION
This section describes the operation and operating characteristics of
the system and subsystems. The operation of the overall system depends on
many variables and conditions. Not all variables are independent, and a
judicious choice of the principal variables must be made to obtain the de-
sired test operation. System characteristics are described in Section 3.1,
whereas subsystems are described in the various following sections.
3.1 SYSTEM CHARACTERISTICS
The FBC test rig has been designed and constructed to operate in the
following basic ranges:
Coal feedrate - 10 to 50 kg/hr (22 to 110 Ibm/hr)
Sorbent feedrate - 0 to 25 kg/hr (0 to 50 Ibm/hr)
Excess air 10 to 300 percent
Bed temperature - 750°C to 1110°C (1380°F to 2010°F)
Fluidizing velocity 1 to 5 mps (3 to 16 fps)
The facility is capable of attaining these ranges, but since the variables
listed above are not independent of each other, the ranges may not all be
attainable at the same time.
The facility has been sized for an optimum operating condition. This
condition was selected near the upper limits of the given ranges to give the
test rig the greatest possible accuracy. The design point conditions are
shown in Table 3-1. The resulting energy balance in the combustor is shown
in Table 3-2. The basic operating ranges define the operating envelope to
the degree that a bed cross-sectional area can be selected. For this
3-1
-------
TABLE 3-1. DESIGN POINT CONDITIONS
Coal feed rate (m )
Heating value (hy)
Air rate (ifr) (20% excess air)
a
Sorbent feed rate (msorb)
/limestone = 50% CaO by wt
I Cals = 3
\3% sulfur coal
Bed temperature (T)
Fluidizing velocity (U )
Heat removal by cooling (Q*.ukes)
Top particle size
31.7 kg/hr (70 Ibm/hr)
23,400 kJ/kg (10,000 Btu/lbm)
289 kg/hr (3990 sdm3) 638 Ibm/hr (141 scfm)
9.98 kg/hr (22 Ibm/hr)
843°C (1,550°F)
1.83 m/sec (6 ft/sec)
455,800 kJ (430,000 Btu/hr)
0.159 cm (1/16 inch)
3-2
-------
TABLE 3-2. COMBUSTOR DESIGN POINT ENERGY BALANCE kJ/hr (Btu/hr)
Energy content of coal 742,000 (700,000)
Energy added to fluidizing air 241,680 (228,000)
Energy removed by cooling tubes 455,800 (430,000)
Energy lost through insulated
walls 31,800 ( 30,000)
Energy lost to offtake ash 4,240 ( 4,000)
Energy lost to elutriated solids 8,480 ( 8,000)
742,000 742,000 (700,000) (700,000)
3-3
-------
2 2
facility, the area has been sized as 968 to 1935 cm (150 to 300 in ) in order to
meet all specified conditions for fluidizing velocity and excess air. Figure 3-1
(Air flowrate versus coal flowrate) and Figure 3-2 (Fluidizing velocity
versus total gas flowrate) show the effects of changing a particular variable.
Figure 3-2 also shows that at least two combustor cross-sectional areas are
required to accommodate the entire range of superficial velocities specified.
This was a necessary compromise, since not all components can tolerate the
high turndown specified and still perform their function. Sizing of the
test rig and its components was based on the design point conditions and the
effects of varying the operating parameters. The values shown in Table 3-3
reflect the maximum and minimum conditions. Table 3-4 shows the pressure
distribution at the design point; Figure 3-3 shows the locations where tem-
perature, pressure, and flow are measured in the system.
Since the flow and temperature ranges are not independent of each
other, setting the flow or temperature at any one location will preclude the
attaining of the entire listed range at other locations. It is noted also
that the total mass air flowrate is composed of two components. They are
the main air flow and the solids transport air. To achieve a desired air
preheat rate the composite temperature must be calculated to arrive at an
accurate value.
Initial tests have indicated that all variables specified as basic
operating ranges can be obtained. The ranges specified, however, were such
that they cannot be obtained without requiring the reconfiguration of at
least the combustor section and the exchange of the distributor plate. The
fluidizing velocity is perhaps the variable causing the greatest inconve-
nience, particularly during startup, if low velocities are desired. The
attainable fluidizing velocity is dependent on the bed material density and
size, the distributor pressure drop, the combustor size and the desired
operating temperature. Low initial actual gas volume flowrates due to low
temperature cause the bed not to fluidize. Increasing the flowrates with
high preheat temperatures results in high pressure drops across the distri-
butor which may limit the maximum attainable flow. Should it not be possible
to inject sufficient air through the distributor, a secondary air port may be
utilized for this purpose during startup.
3-4
-------
1000 i-
Ol
4->
10
100 -
60
(Ibm/hr)
I
10
20 30
mc kg/hr
40
50
hy = 23,400 kJ/kg (10,000 But/1bm)
9 = Design point
Figure 3-1. Air flowrate versus coal flowrate.
3-5
-------
o
o
01 O
> 91
0 »-
16-
12-
o
at
^ 8-
Desiqn T = 1092°C2
'8 on
V range A =96
T = 760° C
A = 968 cm2
1098°C
1451 cn.2
500
= 1451 cm?
T = 760°C
A = 1451 cm2
T = 843° C
A = 1935 cm2
©Design point
1,000 1,500
Total gas mass flowrate (Ibm/hr)
2,000
2,500
I
I
I
1
100 200 300 400 500 600
kg/hr
700 800 900 1000
Figure 3-2. Fluidizing velocity versus total gas flowrate.
3-6
-------
TABLE 3-3. FLOW AND TEMPERATURE DESIGN RANGES
OJ
I
Location
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
a
1133
1133
1133
569
0
0
0
10
0
0
97.5
3.6
79
0
78
0
78
78
78
0
78
Flow
0
- 7080 sdm/min
- 7080 sdm3/min
- 7080 sdm3/min
- 3414 sdm3/min
- 853 sdm3/min
-1133 sdm3/hr
-1416 sdm3/hr
- 50 kg/hr
- 148 kg/hr
- 378 dm3/min
- 654 kg/hr
- 18 kg/hr
- 650 kg/hr
-1.4 kg/hr
- 650 kg/hr
-114 dm3/min
- 650 kg/hr
- 650 kg/hr
- 650 kg/hr
- 1700 sdm/min
- 650 kg/hr
(40
(40
(40
(20
( o
( o
( o
(22
( o
( o
(215
( 8
(175
( o
(172
( o
(172
(172
(172
( o
(172
- 250 scfm)
- 250 scfm)
- 250 scfm)
- 120 scfm)
- 30 scfm)
- 40 Ibm/hr)
- 50 Ibm/hr)
-110 Ibm/hr)
- 326 Ibm/hr)
- 100 gpm)
- 1442 Ibm/hr)
- 40 Ibm/hr)
- 1434 Ibm/hr)
- 3 Ibm/hr)
- 1434 Ibm/hr)
- 30 gpm)
- 1434 Ibm/hr)
- 1434 Ibm/hr)
- 1434 Ibm/hr)
- 60 scfm)
- 1434 Ibm/hr)
0°C -
0°C -
15°C -
15°C -
15°C -
15°C -
15°C -
15°C -
15°C -
15°C -
15°C -
15°C -
15°C -
15°C -
15°C -
15°C -
15°C -
15°C -
15°C -
150°C -
15°C -
Temperature
50
170°C
454°C
454°C
65°C
50°C
50°C
50°C
50°C
60°C
1204°C
1093°C
1204°C
1093°C
1149°C
60°C
260°C
260°C
260°C
260°C
260°C
( 30°F -
( 30°F -
( 60°F -
( 60°F -
( 60°F -
( 60°F -
( 60°F -
( 60°F -
( 60°F -
( 60°F -
( 60°F -
( 60°F -
( 60°F -
( 60°F -
( 60°F -
( 60°F -
( 60°F -
( 60°F -
( 60°F -
(300°F -
( 60°F -
120°F)
340°F)
850°F)
850°F)
150°F)
120°F)
120°F)
120°F)
150°F)
140°F)
2200°F)
2000°F)
2200°F)
2000°F)
2100°F)
140°F)
500°F)
SOOT)
500T)
500T)
500T)
See Figure 3-3
-------
TABLE 3-4. DESIGN POINT PRESSURE DISTRIBUTION
Location3 kPa Pressure (psia)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
99.90
121.95
121.95
121.95
118.51
101.28
101.28
101.28
118.51
406.51
113.00
111.62
110.24
108.86
107.48
413.4
106.80
105.42
104.04
103.35
103.35
(14.5)
(17.7)
(17.7)
(17.5)
(17.2)
(14.7)
(14.7)
(14.7)
(17.2)
(59)
(16.4)
(16.2)
(16.0)
(15.8)
(15.6)
(60)
(15.5)
(15.3)
(15.1)
(15.0)
(15.0)
aSee Figure 3-3
3-8
-------
OJ
vo
Figure 3-3. FBC test rig system schematic.
-------
The operating limitations are indicated in the following subsections.
3.1.1 Operating Preparations and Configurations
To accommodate a test plan and obtain the desired operating para-
meters, the facility will have to be set up in the appropriate configuration.
The principal subsystems requiring configuration adjustments are the com-
bustor section and the flue gas cleanup system.
Variables that affect the combustor configuration are the coal feed-
rate, bed temperature, fluidizing velocity and bed height. Figure 3-2 shows
the gas mass flowrate restrictions for a particular combustor size for the
range of fluidizing velocities or operating temperatures. The total gas mass
flowrate will dictate a coal flowrate for a certain excess air condition
(Figure 3-1). The coal flowrate in turn will dictate the bed energy removal
rate and the amount of heat exchanger surface area.
The first component that must be selected after the combustor cross-
sectional area has been determined is the distributor plate. The guideline to
be followed here is to have a pressure drop across the plate of 0.996 to 3.98 kPa
(4 to 16 inches) of H~0 or 30 percent of the bed pressure drop. The pressure
drop is influenced by the gas mass flowrate, the gas temperature and slightly by
absolute pressure. The distributor plates provided are perforated plates with
varying numbers of holes per area. Four plates are provided with the following
2 2
number of holes for the 1451 cm (225 in ) combustor area covering the indicated
flow ranges. The flow capability is obviously proportional with the number of
holes. The effect of preheat temperatures can be approximated by treating the
holes as orifices. The flow through one 0.254 cm (0.100 inch) diameter hole at
21 °C (70°F) and 101.3 kPa (14.7 psia) has been measured to correspond to 10.8 to
21.54 dm3/min (0.38 to 0.75 cfm) for the 0.996 to 3.98 kPa (4 to 16 inch) H20
pressure drop. (See Table 3-5.)
Select the appropriate plate and install it into the air plenum chamber.
Be sure to use a Fiberfrax or similar gasket at the interface as shown in the
drawing to minimize side leakage.
The next items to be determined are the number of heat exchanger tubes
required to remove the excess bed energy. Bed energy removal is a function of
excess air, air preheat, coal flowrate and energy/kg, facility heat loss,
3-10
-------
TABLE 3-5. DISTRIBUTOR PLATE FLOW RANGE
CO
I
Plate
1
2
3
4
Holes/Plate
1935 cm2 Area
(300 1n2)
n
848
564
376
252
Holes
2
1451 cm Area
(225 in2)
n
632
420
280
160
0
Flow Range 1n dcm /m1n (cfm)
for 1451 cm2 at 15°C
(225 in2 at 70°F)
0.996 to 3.98 kPa AP
(4 1n - 16 in)
6797 - 13424
(240 - 474)
4531 - 8921
(160 - 315)
3001 - 5947
(106 - 210)
1727 - 3398
(61 - 120)
-------
energy lost to the offtake ash, energy lost to elutriated solids and the
reaction of the sorbent with S02. A good approximation, however, can be
made by simply considering three of these components miscellaneous and assign-
ing 9376 watts regardless of operating conditions. This reduces the energy
equation to:
q tubes - q coal - q air - 9376 watts
hnAtube {tbed " ttube) = "coalh/ '"air (tair in ' W bed* ' 9376
. "c ' hv - "air "air in "W bed* " 9376
h atube (tbed ' ttube)
Some. of the values to be used in this equation are still not known accurately
since only few test runs have been made, h must be estimated to lie in the
range of 255.6 to 368 W/m2K (Btu/ft2 - °F-hr), increasing with fluidizing
2 2
velocity. The area of each cooling tube is equal to 0.0403 m (ft ) and the
maximum t. . should not exceed 93°C (200°F) to prevent boiling. Heat exchangers
with five and seven tubes have been provided. Some small adjustment in the heat
transfer is possible by varying the water flowrate; however, the principal
temperature control of the bed rests with the coal feedrate. After determining
how many cooling tubes are required to establish the appropriate test condition,
the heat exchangers should be installed in the desired locations.
The remaining ports are available to mount secondary air injection
ports and sight or sampling ports.
The air injection ports provide the user with the capability to inject
air in the desired location of the combustor or into the freeboard. The
secondary air supply panel is very versatile and allows for the insertions
of tubes of various lengths at almost any location.
The view and sampling ports are also designed and constructed to pro-
vide versatility. Care must be exercised to use them as intended to avoid
injury. The panel provides access to the bed or freeboard via a 7.6 cm (3
inch) pipe (SS 330). This pipe can be blocked by a 7.6 (3 inch) slide gate
valve to maintain the view glass clear or while installing a sampling adapter.
Low pressure purge air (34.5 kPa (5 psi)) may be applied to blow debris from
3-12
-------
the port through an adapter on the side of the access pipe. Two sizes of view
ports are provided, a 3.8 cm (1-1/2 inch) and a 7.6 cm (3 inch) peepsight. The
The 3.8 cm (1-1/2 inch peepsight is rated at 689 kPa at 38°C (100 psi at
100°F) and 413 kPa at 204°C (60 psi at 400°F). The large view port is rated
for 69 kPa (10 psi). The small peepsight is intended to be used in the bed
area whereas the large unit may be used in the freeboard.
All remaining combustor and freeboard ports must be closed by install-
ing a refractory plug and installing a cover plate.
The configuration of the flue gas cleanup devices is prescribed by
each test. It is anticipated that the primary cyclone will always be used
to accomplish the preliminary collection of particulates. From the primary
cyclone the flue gases may be routed to the secondary cyclone via damper
control or to the flue gas heat exchanger. The baghouse or the ESP may be
connected to the flue gas heat exchanger in parallel or in series. Other
control devices can be installed and connected utilizing the supplied flex-
ible ducting. Since the flue gas ducting is under slight positive pressure
to expel the gas out of the stack, the configuration of the cleanup devices
will change the pressure drop characteristics of this part of the system.
For sampling purposes positive pressure is not desirable since the probe
entry ports would have to be sealed to reduce the hazard of high-temperature
exhaust gases. A damper-controlled stack draft fan may be the ultimate
solution to this drawback.
The test plan further calls for the type of coal and sorbent to be
used in the FBC Test Rig. These materials must be loaded into their re-
spective feed bins. Both the coal and sorbent must be screened for particles
larger than .63 cm (1/4 inch). Loading of the bins is discussed in greater
detail in the Solids Feed System Subsection.
Before the system can be started, a bed of fine inert material mixed
with 5-10 percent coal must be loaded into the combustor. The material can be
either from a previous run or shale of the appropriate size. It can be loaded
into the combustor in two modes. Material can be loaded through a sampling
port, or it can be fed pneumatically from the third solids feed bin when it is
not used to recycle ash from the primary cyclone. The second method has the
advantage of being able to raise the bed height faster during startup.
3-13
-------
Limestone should not be used to start the bed since it requires a great deal
of time to neutralize it and stabilize the reaction after startup.
The system is now ready for startup.
3.1.2 Startup
After the equipment has been prepared, a final visual check should
be made of the system to verify the proper test configuration and that
everything is properly installed and fastened down. The following described
startup sequence can then begin.
Step 1
Close the water system drain valve.
Step 2
Open the main water valves for water supply and discharge. Note
the differential pressure on the two local gages. The inlet
pressure is typically between 206 kPa (30 psi) and 276 kPa (40 psi)
and the discharge pressure between 138 kPa (20 psi) and 172 kPa
(25 psi). A minimum differential pressure of 41 to 69 kPa (6 to
10 psi) is required for proper heat exchanger operation.
Step 3
Turn the coolant flow to all heat exchangers off by turning the
three-way inlet valves to the vent position. Observe the flow
indicator gages on the control console for zero differential
pressure. (A pegged gage may indicate air in the instrument
line bleed the line if this is the case.) The waterflow
indication system responds slowly to any flow adjustments and
adequate time must be allowed.
Step 4
Check the power circuit breaker panel and insure that all breakers
are in the on position for startup.
Step 5
Close the air line valves to the solid feed system (2) and the
ash dump valve.
3-14
-------
Step 6
Start the air compressor by placing the wall switch in the on
position. Observe the air line pressure on the gage mounted on
the wall over the blower.
Step 7
Push the power on button on the control console.
Step 8
Open the main air valve located near the blower approximately
one turn.
Step 9
Start the blower by pushing the blower-on button and establish
3
a high air flowrate (5664 to 7080 dm /min (200 to 250 scfm)) by
adjusting the main air valve. (See Figure 3-4.)
Step 10
Check the solid injection tube valve near the combustor to insure
it is closed. Turn the baghouse on.
Step 11
Turn power to the main air temperature controllers on. Set
the sheath temperature controller to 815°C (1500°F) and the
air temperature controller to 538°C (1000°F). "Reset" the
controllers by pushing the reset button until the blinking
light goes out.
Step 12
Push the heater on power button and hear the contactor close.
Observe the temperature rise on the sheath temperature indicator.
Step 13
If no or little bed material is in the combustor, start feeding
the material from the small bin by the following procedure.
Step 14
Turn the valves located on the pneumatic control panel for the
purge air (V-112) and transport and vibrator air (V-120) on.
Step 15
Set the primary regulator (PCV-118) to 620 kPa (90 psig).
3-15
-------
0
I
10
I
IS
I
20
I
30
I
30
I
"SKJ
o
100
200
300
400
500
550
-10 0 10 20 30 40 SO flO 70 80 90 100 110 120 130 140
f> * 0.048 (0.03)
ig AIR DENSITY - P IN QLDM'(LBM/FP) R
PIPE ID 10.2 CM (4.0M-)
ORIFICE DIA.
4.12 CM (1 825")
ORIFICE OIA.
6.03 CM (2.375")
2.00
1.50
1.00
0.75
050
0251
P - 1.6 (0.1)
« 1.44(0.0*)
P = 1.28 (0.08)
> 1,12 "(0.07)
3 4 56789
X 100 LBS/HH FLOWRATE
25 30
40 SO SCFM 80 90100 12S 150,175,200 250 300
kg/or
SO
75 100
150 200
300 400 500 600
Figure 3-4. Main air flow versus pressure drop.
3-16
-------
Step 16
Set the secondary regulator (PCV-119) to 482 kPa (70 psig).
Step 17
Set the purge air regulator to 68 to 136 kPa (10 to 20 psi) and
the rotameters to 2.8 sdm3/min (0.1 scftn) (Fl-100, Fl-101).
Step 18
Set the ejector inlet regulator (PCV-121) to 13.8 kPa (2 psi).
Step 19
Open the solid injection tube valve near the FBC.
Step 20
Set the ejector air supply regulator (PCV-120) to the required
pressure for the needed pressure rise across the ejector.
See Figure 2-16.
Step 21
Set the bin vibrator air supply regulator (PCV-117) to ss344 kPa
(si50 psig).
Step 22
Note the loadcell readout in the small bin position. Turn the
potentiometer to zero and turn the solids feedrate for the
vibrator on. Increase the solids flow and observe the feeding
through the sight glass.
Step 23
Stop the feeding of solids when the desired amount is in the
combustor.
Step 24
The system has been heating up and will have reached 343 to 371 °C
(650 to 700°F) in 1 hour sufficient for lightoff. If 5 to 10
percent coal is present in the bed material, lightoff will occur
automatically; otherwise coal feed must be started for this to occur.
Step 25
Lightoff can be observed through one of the 3.8 cm (1-1/2 inch)
sight ports. Be sure to purge the sight glass with 207 kPa (30 psi)
purge air.
3-17
-------
Step 26
Open the air shutoff valve to the ash dump valve. Set the
upper limit on the bed level control gage.
Step 27
Include the solids feed and check the timing cycles in the back
of the control consoles on the bin vibrators. Switch on only
those vibrators required.
Step 28
Lightoff results in a rapid increase in the bed temperature
observed on the bed temperature probe indicator. A decrease in
the airflow will result in faster increases in temperature as
well as an increase in coal feed.
Step 29
When the bed reaches 1200°F turn on the water flow to the lowest
heat exchanger in the bed. Do this gradually to cool the tubes
slowly. Turn on the water flow to the diplegs also. (See Figure 3-5.)
Step 30
Further increase the coal feed and turn on the next heat
exchanger, etc.
Step 31
Check the cooler temperature and turn on coolers starting from the
top to maintain an outlet temperature of less than 260°C (500°F).
Step 32
Start the sorbent feed.
Step 33
Adjust the coal feed and reduce the air preheat temperature to
the desired value.
Step 34
If the bed was low on startup, allow the bed to increase in
height growing into the heat exchanger cooling tubes. Further
increase the coal feedrate to maintain the temperature of the
bed.
3-13
-------
10.00
7.50
5.00
3.75
kPa 2.50
2.00
AP
1.25
1.00
0.75
0.50
0.25
Orifice Flowrate vs. Pressure Drop
I
0.907
Orifice
1.61" Line
in
T~
I
1.625"
Orifice
2.469" Line
1.250"
Orifice
2.469" Line
2 3 4 5678910 20 30 40 50 60 708(90 100
Gpm
10
20
40 60 80 100 150 200
Figure 3-5. Coolant flow versus pressure drop.
3-19
-------
Step 35
Adjust the timing cycle on the ash dump valve. Timer one adjusts
the buzzer before the valve opens (0 to 5 seconds). Timer two
adjusts the closing time after the buzzer starts to operate
(0 to 10 seconds) and timer three adjusts the cycle time between
actuation (minimum 6 minutes/maximum 60 minutes).
Step 36
Check and make final adjustments until the desired operating
condition has been obtained.
Several comments are made here to help in successfully starting the
combustion unit and minimizing any damage.
The heat exchangers were designed for water cooling only. Reducing
the flow to the flash point is undesirable. Quenching of the bed during
startup should be avoided by not allowing the tubes to be submerged or by
not establishing any flow in the tubes. The energy removal capability of a
submerged exchanger is 4 to 5 times that of one in the freeboard. The tubes
are made from SS 310. The tubes should be exposed to temperatures in the 427
to 482°C (800° to 900°F) range for short periods only to prevent sensitization or
carbide precipitation to the grain boundary. Higher or lower temperatures
are acceptable.
Prolonged operation of the blower without flow should be avoided. It
is therefore recommended to open the main air valve at least one turn.
The air heater will not operate without a certain minimum flow.
The ash recycle bin may be used to store inert material if ash feed
is not required for a test condition.
During startup the pressure drop across the distributor plate will be
exceptionally high and particularly with high preheat temperatures. This is
normal. Fluidization of the bed is also not likely to occur until a minimum
fluidization velocity with increasing temperature has been achieved.
Until lightoff has occurred it is suggested to operate the unit
adiabatically as much as possible - no heat exchanger surface submerged.
The unit should be brought on line gradually to minimize damage to the
refractory.
3-20
-------
The baghouse should be bypassed until the exhaust gas temperature is
high enough to prevent condensation (122°C (252°F)). This is not necessary
with preheated air.
The method suggested to start the combustion has been successfully
employed but requires many adjustments before the final operating condition
can be acquired. Large volumes of preheated air would be required to speed
up this process or to withdraw heat at the same time via heat exchanger.
Should it not be possible to start the combustion in the outlined fashion due
to a particular test configuration, a lit butane or natural gas lance may be
inserted in the lower portion of the bed for the additional energy required.
3.1.3 Shutdown
Shutdown of the system is extremely simple. The only concerns rest
with the protection of the refractory components and minimizing thermal shock.
The steps to be followed are the following:
Step 1
Reduce the coal feed rate gradually and reduce the temperature of
the combustor to s;425°C (^800°F).
Step 2
Discontinue coal and sorbent feed.
Step 3
Cool the unit further with air, minimizing thermal shock for
refractory protection.
Step 4
If the heater was on, turn if off.
Step 5
Turn all heat exchanger coolant flows off and vent the heat
exchangers.
Step 6
Turn the air supply to the dump valve off.
Step 7
When the combustor has cooled to 600°F, turn the blower off.
3-21
-------
Step 8
Adjust the ejector air supply pressure to zero and close the
solids feed line valve.
Step 9
Turn the transport vibrator air and purge air valves to off.
Step 10
Turn the control console power off.
Step 11
Close the main water valves and open the drain valve.
Step 12
Turn the circuit breakers on the power panel to off.
Operator judgement should be used in the speed with which the system is
shut down. Fast shutdown will result in higher refractor repair requirements.
The facility is equipped with a number of safety interlocks designed
either to warn the operator or to automatically shut off subsystems. The con-
trol console power-off knob will shut down all electrically controlled systems,
principally the solids feed system, the air preheater, the blower, the bag-
house and the ESP. The severity of the malfunction of course dictates the
action. To prevent slug formation the bed will be dumped when the air flow
is too low for fluidization or upon a power failure.
3.2 COMBUSTOR OPERATION
The combustor itself is primarily a passive element although it houses
the combustion. Few controls are located on or near the combustor. The fol-
lowing paragraph will therefore describe the expected conditions of normal
operation of its components.
Combustor and Freeboard Sections
The combustion chamber is refractory lined and sensitive to high-
temperature fluctuations over short periods of time. To minimize thermal
shock, one to two hours are required for warmup and cool down. The expected
surface temperature of the combustion chamber at 900°C (1650°F) operating
combustion temperature is 100°C (212°F).
3-22
-------
During the operation the combustor is under positive pressure. The
extent of pressurization depends on the flowrates and the gas cleanup system
configuration. This feature, however, requires frequent verification that
packings and seals on the combustor are airtight. Small leaks tend to grow
larger because they cause high-temperature gases to pass to the combustor
shell and cause seal erosion.
Distributor Plate
The distributor plate pressure drop should be approximately 30 per-
cent of the bed pressure drop. The combustor has been designed to accom-
modate a maximum 122 cm (48 inch) bed depth and 0.8 kg/dm3 (50 lbm/ft3)
solids density this results in a maximum 4.5 kPa (18 inch h^O) pressure
drop requirement for the distributor plate. Solid to fluidized bed expansion
is assumed to be ^1:2. The operation of the distributor plate must be
anticipated to allow the proper selection. The distributor plate operates
near the bed operating temperature and could experience two modes of failure:
plugging or breakthrough. Both failure modes can be detected by the change
in pressure drop across the plate. A higher than normal pressure drop
indicates plugging and a lower than normal pressure drop breakthrough.
Both failure modes require the shutdown of the facility and correction of
the problem.
The distributor plate can be operated at a lower temperature by
introducing a layer of large inert pebbles (0.95 cm (3/8 inch) in diameter)
into the bed. This layer of pebbles (2.5 to 7.5 cm (1 to 3 inches) thick)
acts as an effective insulation layer in which little combustion takes place.
This may be a desirable mode of operation for some high-temperature tests.
Rapid corrosion rates have been witnessed for material temperatures above
900°C (1650°F) resulting in damage to the distributor at other facilities.
Heat Exchangers
Two types of heat exchangers are provided for the combustion section --
five and seven tube modules. The heat exchangers can be inserted in the
desired location of the bed. The design requires that they be operated in
the liquid coolant phase. Flashing can be prevented by establishing a
minimum heat exchanger tube flow of 2.7 kg/min (6 Ibm/min). A five-tube
bundle therefore requires 13.5 kg/min (30 Ibm/min) and a seven-tube bundle
32.6 kg/min (42 Ibm/min) minimum flow.
3-23
-------
Each heat exchanger outlet is equipped with a thermocouple. Should
the outlet temperature of a heat exchanger exceed 82°C (18Q°F), the flowrate
should be increased. The bulk water outlet temperature should not exceed
60°C (140°F) to protect the cooling tower. An alarm light will indicate
the overtemperature condition and cause the solids flow to be discontinued.
Flowrates to the heat exchangers can be controlled by two control
valves across two orifices of low and high flow capacity. For low flow re-
quirements the 3.8 cm (1-1/2 inch) diameter Schedule 40 line is equipped
with a 2.30 cm (0.907 inch) diameter orifice plate. The 6.35 cm (2-1/2 inch)
diameter Schedule 40 line is equipped with a 3.27 cm (1.250 inch) diameter
orifice. A spare 4.13 cm (1.625 inch) diameter orifice for higher flow
capabilities for a 7.5 kPa (30 inch) HoO pressure differential has been
delivered. Flow characteristics are shown in Figure 3-4. These curves
apply to the combustor coolant flow circuits as well as the flue gas
coolant circuits. These curves are generated from the general orifice
equation
= KaYFa /2g (Ap) p
where
= 0.5930 + 0.4S1
K
a
Y
Fa
gc
Ap
p
6
(0.0015^+ 0.012BH),rjP-
D
= gravimetric flowrate
= orifice coefficient
= orifice area
= expansion factor
- coefficient for thermal expansion of the orifice plate
= scaling factor
= differential pressure across the orifice
= density as a function of temperature
= diameter ratio
Rn = Reynolds number
3-24
-------
When a heat exchanger is mounted in the combustor but has no estab-
lished coolant flow it must be vented to the drain. This is done automatic-
ally when the three-way valve is turned to close the flow off. It is im-
portant, however, to turn the valve handle completely so as not to block
flow in both directions. The drain hose to the drain header must also be
secured and all open drain openings plugged to prevent splashing.
Bed Height and Temperature Sensors
Pressure and temperature measurements are made in various locations
of the combustion and freeboard sections. All thermocouples are Type K,
whereas the temperature switches are of the capillary type. The pneumatic
signal lines may plug on occasions and may have to be cleared by purging.
Pressure measurements are made with magnehelic gages that require little
maintenance. To insure accuracy of the measurements, the "zeros" should be
checked before a run.
Sampling, View, and Secondary Air Ports
The sampling and view ports can be mounted in the unused access ports
of the combustion or freeboard sections. The 7.62 cm (3 inch) peepsights are
intended for use in the freeboard area where the 3.81 cm (1-1/2 inch) units are
to be used in the fluidized bed region. Care must be used to apply safe purge
air pressures to these ports while the slide gate valve is closed. The large
units are rated for 69 kPa (10 psi) purge air whereas the small units may be
used with up to 689 kPa at 38°C (100 psi at 100°F) and 413 kPa at 204°C (60 psi
at 400°F). A regulator with adjustment capability up to 413 kPa (60 psi), hose,
quick connects and shutoff valves is provided.
Secondary air ports are provided that allow injection of air into the
fluidized bed or into the freeboard region. Flexible metallic hoses connect
to these ports and essentially allow the bypass of the distributor plate.
The operation and control of the air quantities is discussed in the section
for the air system.
Ash Removal System
The bed height is controlled by removing excess quantities of bed
material through the 5.08 cm (2 inch) diameter ash dump pipe located in the
center of the distributor.
3-25
-------
Bed height is measured by noting the pressure differential between
three known points two in the bed region and one in the freeboard. The
bed density is measured by noting the pressure differential between two
points, a known distance apart within the bed, and the bed height by pro-
portion to the third port. The bed density measurement is made and indicated
by gage DP1-107. The connection of the pressure tabs should be verified at
the time of the test to insure reliable bed height data.
The bed height is indicated by Photohelic gage DPI-106. The Photo-
he! ic gage controls a solenoid valve between two manually adjustable set-
points that direct the opening or closing of the bed dump valve. The upper
setpoint needle triggers a timing circuit that will sound an alarm, open the
valve for up to 10 seconds and limit the dumping of bed material to once every
6 to 60 minutes. The duration of the alarm, opening and closing of the valve and
the repeat cycle are independently variable. This feature allows the automatic
bed height control of the fluidized bed within a very close tolerance band.
3.3 AIR SYSTEM OPERATION
The air system supplies the required combustion air to the combustor
at the various desirable locations at the desired preheat temperature. It is
also possible to recirculate up to 25 percent of the flue gas for flue gas
recirculation. The prime gas mover is a Spencer turbine blower. The system
is easy to understand and operate. The flow is controlled by manual valves
at the various strategic locations. Flow measurements are indicated by
pressure and temperature measurements across orifices. Figures 3-5, 3-6 and
3-7 show the flowrates for a number of limited cases. The general orifice
equation shown in Section 3.2 should be used to compute the accurate flow
measurement for the specific desired operating condition.
The various air supply lines have been equipped with orifices of the
following indicated sizes. Several plates have been provided for some lines
for high and low flow capabilities.
3-26
-------
250
2.00
1.50
ORIFICE
3.34 CM (1 312") DIA
kPl
1.00
0.50
025
250
2.00
1.50
100
PIPE I.D 5.25 CM (2.067-)
ORIFICE
2.22 CM (0.675") DIA
ORIFICE
3.5 CM (1.375") OIA.
kPa
Q
050
0.25
789 20
X 100 LBS/HR FLOWRATE
I
6 7 8 9 10 125 15
20 SCFM 30
I
40
I I I I I I
90 60 70 80 00 100 125
10 15
20
38
50
KG/MR
75
100
150 200
Figure 3-6. Secondary air and FGR versus pressure drop.
3-27
-------
SCFM
sdm3/m1n
900 -
soo -
700-
600 -
500
400 -
300 -
200 -
100 -
0
35-
32
30
25-
20-
15-
10-
5-
AIR FLOWMETER INLET PRESSURE
10
15
20
25
1.25
I
2.5
I
3.74
I
5.0
6.23
AIR FLOWMETEH YP
30
75
calibration pressure: 620 kPa (90 psi)
temperature: 26.7°C (80°F)
o
Figure 3-7. Air flowmeter AP versus sdm /min (scfm)
3-28
-------
Measurement " P* ?1 ze Ori fi ce Si ze
Schedule 40 cm (in)
Main air 10.2 cm (4") 6.03 (2.375)
Main air 10.2 cm (4") 4.13 (1.625)
Hue gas 5.1 cm (2") 3.33 (1.312)
Secondary air 5.1 cm (2") 3.50 (1.375)
Secondary air 5.1 cm (2") 2.22 (0.875)
The measured pressure differentials are indicated on the control console by
the appropriate gages.
Startup
Step 1
Open the mixing chamber valve.
Step 2
Open the main air valve one turn.
Step 3
Supply power to the control console.
Step 4
Push the blower start button.
Step 5
Adjust the main flow to the desired flowrate.
Step 6
Set the heater controllers to the desired air temperature.
Check the sheath temperature controller for proper setting.
Step 7
Apply power to the heater by turning the heater power switch on.
Step 8
Observe the air temperature indication. To establish a secondary
air flow do the following.
Step 9
Insure the flexible air duct is connected to the air port and
open the appropriate valve slowly. Opening the valve too far
may result in the loss of fluidization due to the loss of head
at the distributor plate.
3-29
-------
Step 10
For secondary temperature control, adjust the two mixing
valves. If more back pressure is required, throttle the flow
with the 10.2 on (4 inch) valve before the air plenum.
Step 11
Adjust the total flow to compensate for pressure and temperature
changes.
Step 12
Flue gas recirculation is established by opening the 5.1 cm
(2 inch) FGR line valve.
Step 13
Slowly close the mixing chamber 10.2 cm (4 inch) valve until the
desired flowrate is established through the FGR line.
Shutdown
Turn the heater and blower power off.
The air system has a number of safety interlocks that protect it from
damage and furthermore require the startup sequence to be followed. The blower
is rated for 7080 sdm3/min (250 scfm) and a pressure rise of 34.5 kPa (5 psi)
at up to 93°C (200°F) inlet temperatures. The blower will shut off if this
temperature is exceeded. If the flowrate is exceeded the blower will thermally
overload the motor and shutdown will also occur. To keep the blower from
surging the flow should never be blocked completely. This is why it was re-
commended to crack the main air valve one turn.
The heater is protected by two interlocks. Low air flow and high
heater sheath temperature will both cause the heater to cut out.
The interlock sensors should be checked periodically to insure that
they indeed supply the expected protection. Adjustments requirements are
discussed in the component literature.
Service of the air system components is minimal. The blower needs to
be lubricated periodically as outlined in the Spencer service manual and
the Oemister screen and inlet filter should be cleaned as required.
3-30
-------
3.4 SOLID FEED SYSTEM
The solid feed system has been designed and constructed to meet the
required performance characteristics listed in Table 3-6.
Section 3.4.1 describes safety considerations, bin loading, startup,
steady-state operation, shutdown and bin unloading. Calibration and setup
of the load cells, flowmeters, feeders, relief valves and timer is discussed
in Section 3.4.2.
3.4.1 Safety Considerations
The safety precautions necessary to operate the solid feed system
are minimal and straightforward.
The most important safety precaution is to verify the operation and
adjustment of the two pressure relief valves. Adjustment of these valves is
covered in Section 3.4.2.
Another necessary safety precaution is to insure that everything is
tight and in place, insure that the plexiglass viewport has been uniformly
tightened down, and that the handrails are installed and bolted securely.
Bin Loading
The bins can be loaded in one of two modes. They can be loaded with
the solid feed system operating, or without. The actual loading procedure
is identical except for one additional step if the system is operating.
During operation of the system, it is necessary to reduce the bin pres-
sure to atmospheric pressure. To do this it is necessary to have at least
566 sdm3/min (20 scfm) of transport (primary) air flow. If it is necessary to
increase the transport air flow, total combustion air can be maintained (if de-
sired) by decreasing the fluidization or secondary air. To reduce the bin pres-
sure to atmospheric conditions, increase supply air (with the supply air regula-
tor on the local control console) to the value shown in Figure 2-16 correspond-
ing to the existing FBC inlet pressure and to zero inlet air pressure. Follow-
ing, reduce the inlet air flow to zero (with the inlet air regulator on the
local control console). It may be necessary to readjust the supply air now
to achieve atmospheric pressure in the bin.
3-31
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TABLE 3-6. SOLIDS FEED SYSTEM SPECIFICATIONS
Dust Feedrates
Coal 10-50 kg/hr (22 - 110 Ib/hr)
Sorbent 0-25 kg/hr (0-50 Ibs/hr)
Ash 0- 9 kg/hr (0-20 Ibs/hr)
Particle Size 0.63 cm (to 1/4") (max dia)
Bin Capacity
Coal - 935 dm3 (33 cu ft)
Sorbent 396 dm3 (14 cu ft)
Ash 198 dm3 ( 7 cu ft)
Run Time (at max. flowrate)
Coal (at 50 kg/hr) - - 15 hrs. - assumes: 0.80 kg/dm3 (50 lbs/ft3)
Sorbent 21 hrs. - assumes: 1.2 kg/dm3 (75 lbs/ft3)
Ash 12 hrs. - assumes: 0.56 kg/dm3 (35 lbs/ft3)
Air Flowrate to 906 sdm /min (32 scfm)
Air/Fuel Ratio from 1.25 kg (Ib) air/kg (Ib) solids
3-32
-------
Example: Given the following conditions
t FBC inlet pressure - 11.2 kPa (45 in WG)
0 Air supply pressure -68.9 kPag (10 psig)
Inlet supply pressure - 34.5 kPag (5 psig)
This would correspond to approximately 396 sdm3/min (14 scfm) air flowrate and
9.2 kPa (+37 inch WG) bin pressure. To load the bins, it is necessary to in-
o
crease the air flowrate to 736 sdm /min (26 scfm) which corresponds to approx-
imately 503 kPa (73 psi) supply air pressure and zero inlet air.
Actual loading details are simple. Remove the lid(s) or cap(s), attach
the funnel and add material. Make absolutely sure that the maximum particle
size is not in excess of 0.64 cm (1/4 inch) (maximum dimension). It is easier
to screen the material before loading. Replace lid(s) or cap(s) and tighten
uniformly.
Startup
Using Figure 2-16, pick a set of air inlet and supply pressures that
satisfy the air flowrate requirement. It is usually to advantage to run as
much inlet air as possible, but some supply air should be used to avoid get-
ting dust into that section of tubing.
With the FBC inlet valve closed, turn on the air and set the
desired inlet and supply pressures (on the local control console).
As the bin pressure reaches 12.45 to 14.94 kPa (50 to 60 inch WG),
open the FBC inlet valve
Set the purge air (on the local control console) to approximately
2.8 sdm3/min (0.1 scfm)
Set each solids feedrate to the desired level. Refer to Section
3.4.2 for calibration procedures.
Turn on flyash vibrators. Also turn on coal and sorbent vibrators
if either bin is near empty.
Recheck and fine-tune the air flowrate using Figure 3-7 and the
flowmeter gages on the remote control console.
3-33
-------
Fine-tune the solids feedrate by monitoring the loadcell readout
of each. The potentiometers have been equipped with a range
control that can be adjusted from the back.
Steady-State Operation
Duties required for steady-state operation are minimal. They are:
Solids feedrate adjustment and monitoring - feedrate 1s computed
by noting the change in loadcell reading over a known time span.
However, it must be noted that the vibrators, or changes in bin
pressure, may have a slight effect on the loadcell reading. It
is best (most accurate) to take readings at an arbitrary condition,
e.g., take reading with the vibrators on, and with a bin pressure
of 7.5 kPa (+30 inch WG). It is possible to maintain a given bin
pressure while changing air flowrate or FBC bed height by changing
the ratio of inlet air pressure to supply air pressure. Consult
Figure 2-16 for this information.
Air flowrate adjustment and monitoring air flowrate is computed
from flowmeter inlet pressure and differential pressure informa-
tion (from the remote control console), and the flowmeter calibra-
tion curves shown in Figure 3-7. Temperature corrections can be
made by multiplying the flowrate given in the figure by the ratio
of the calibration temperature 26.7°C (80°F) to the actual tem-
perature (in absolute units).
Loading three indicator lights on the remote control console
indicate when each of the bins are getting empty. Loading
instructions are given in this section to assure leak-tight
operation.
When the air-flow ratio (between inlet air and supply air) is varied
it is important to maintain the air flow in the transport line (to avoid
clogging).
Bin Unloading
To unload the dust from each bin, it is necessary to open the unloading
port (7.6 cm (3 inch) pipe plug) at the bottom of each cone, and let the material
3-34
-------
fall along a chute, tray, or tube into a drum or barrel. The plug can be
easily replaced even with the bin partially full.
Shutdown
Shutdown of the solids feed system is accomplished in the reverse
order of startup:
Turn off bin vibrators
Turn off vibratory feeders
Shut FBC inlet valve
Shut off purge air
Shut off transport air
3.4.2 Solid Feed System Calibration and Setup
This section covers the adjustment and/or calibration of all of the
applicable devices in the solids feed system. Some devices like the flow-
meter and the loadcells need to be (or have been) calibrated only once.
Others like the feeders and vibrator timers change their characteristics
with any material change, and may have to be readjusted or recalibrated.
The pressure relief valve should be checked periodically and readjusted if
necessary.
Loadcells
Raw output from the loadcell is conditioned by an Action-Pak Model
AP 4051 signal conditioner (located in the back of the control console). The
Action-Pak unit is equipped with an adjustable span and zero. This conve-
niently makes it possible to subtract the weight of the empty bin from the
total weight and indicate only the material.
Set the zero value with each bin completely empty (with the lids
and lid bolts on). Make sure that the internal gage pressure in
the bin is zero, as this has a slight effect on the reading. If
the bin weight cannot be completely eliminated because the zero
adjustment is not sufficient, choose a value of 100, 1000, or
some other convenient number.
3-35
-------
To set the span, add a known weight of dust to each bin and ad-
just the span to read this value. It Is possible that the span
adjustment will not have the range to reach the required value.
For this case It is necessary to increase or decrease the amount
of excitation of the signal conditioner. This adjustment is also
on the Action-Pak module. If the excitation is changed, it is
necessary to repeat the zeroing procedure above.
The loadcell readout can be calibrated in virtually any units. It
must be noted, however, that the decimal point is not shown. For example,
a flyash readout of 1456 is actually 145.6 Ibs. The coal and sorbent, how-
ever, have the decimal at the extreme right.
The limit alarms, used to indicate a low bin-level condition in any
bin, are Action-Pak Model 1020's. These are also located in the back of the
control console. The easiest way to adjust these units is to add the amount
of material that represents a near-empty condition, and adjust the Action-
Pak module until the indicator light turns on. An alternate method is to
apply an adjustable voltage to the input of the signal conditioner to repre-
sent a loadcell output.
Recommended level alarms are:
Coal bin -- 50 kg (110 Ibs)
Sorbent bin -- 22.6 kg (50 Ibs)
Ash bin 9.06 kg (20 Ibs)
These loads give a 1-hour warning to the operator.
Flowmeter
The flowmeter, a Meriam Model 50MJ10 laminar flow element, has been
calibrated in its present configuration. The calibration was done at 620 kPa
(90 psig) and 26°C (80°F) inlet conditions. The calibration curve is shown
in Figure 3-7. Flowrates for other inlet pressures have also been calculated
and plotted on the figure.
3-36
-------
Temperature corrections, as explained in Section 3.4.1, can be made
by multiplying the value obtained in Figure 3-7 by the ratio of the calibra-
tion temperature (26.6°C (80°F)) to the actual temperature usinq absolute
temperature units.
Feeders and Feed Nozzles
To determine initial solids feedrate settings, it is necessary to have
at least a rough calibration of feeder performance. Since solids feedrates
are dependent on material characteristics (density, particle size distribu-
tion, etc.) it is necessary to recalibrate it for every change in dust
characteristics.
Calibration of the feeders is a simple matter. Feedrate is not a
function of bin pressure or air flowrate. The transport line can be removed
and the dust fed directly into a bucket for subsequent weighing.
If it should be necessary to change the characteristics of the feed-
rate curves (either because the feeder does not feed fast enough, or because
the feedrate control is too sensitive), some methods are:
Nozzle height - the clearance between the feed nozzle and the
feeder tray can be varied to increase or decrease the maximum
solids feedrate. The larger the clearance is, the larger the
pile of material on the tray will be, and hence the higher the
maximum feedrate will be. However, as the pile gets larger,
the flow quality goes down.
t Nozzle gate position nozzle gate position has the same effect
on feedrate and flow quality as nozzle position. It has the
additional drawback of increasing the likelihood of clogging in
the low position.
Feeder tray inclination as the feeder tray inclination increases,
so does the feedrate and flow quality. The limiting factor is
purely physical interference with the feed nozzle and with the
mixing cone. The feeder tray inclination is varied by changing the
standoff height of the feeder mount. If the feeder tray inclina-
tion is changed, insure that the standoff-box interface is airtight.
3-37
-------
Feeder performance is optimized when the maximum design feedrate is
at roughly 90 to 95 percent actual maximum. The nozzle gate should be as much
open as possible, the nozzle as low as possible, and the feeder tray inclina-
tion as steep as necessary.
Relief Valves
To keep the bins from ever being pressurized to more than 34.5 kPa
(5 psig), two redundant pressure relief valves are included in the solids
feed system.
The pressure relief valves are adjustable within certain limits. They
must be checked and adjusted at frequent intervals to assure safe operation
of the system.
The relief pressure is set by adjusting the preload on the spring in-
side the valve; higher preload results in a higher relief pressure.
The following steps outline the procedure used in setting the relief
pressure.
Step 1
Set the spring preload to the minimum value.
Step 2
Pressurize the relief valve, and note the relief pressure.
Step 3
If the relief pressure is less than the desired value, increase
the spring preload by a small amount. Repeat Steps 2 and 3 until
the relief pressure is at the desired level.
Vibrator Timers
The vibrator timers are located in the back of the control console.
They are adjustable for both on-time and off-time. Suggested setpoints are
given in Table 3-7 but, because dust-flow characteristics are so variable,
the final setpoints must be determined by experience.
3-38
-------
TABLE 3-7. SUGGESTED VIBRATOR TIMER SETPOINTS
On Time (seconds) Off Time
Coal Bin
(Cone Vibrator)
Sorbent Bin
(Cone Vibrator)
Ash Bin
(Cone Vibrator)
(Down -Comer
Vibrator)
30*
30*
10
10
3
3
5
20
Coal and sorbent should have to be turned on only when the bins are nearly
empty.
3-39
-------
Vibrator tinting should be set to run as little as possible while
continuing to give satisfactory performance. There are two reasons for this:
first, it will minimize the air consumption, and second, it will also
minimize the chance of packing or segregating of any of the materials.
3.5 GAS CLEANUP SYSTEM OPERATION
The gas cleanup system can be classified into two sections. The high-
temperature sections employ two cyclones for particulate control and the
low- (260°C (500°F)J temperature cleanup section a baghouse and an electro-
static precipitator. Operation of these devices is outlined in the following
subsections.
Primary Cyclone
The primary cyclone is a rather passive element once the basic con-
figuration has been established. This particular unit is equipped with a
SS 310 outlet tube insert that may be changed to slightly alter its per-
formance characteristics and pressure drops.
The dipleg is equipped with a water jacket that can be utilized
should the amount of solids collected require active energy removal. A
manual valve controls the flow to this jacket. Care must be exercised to
prevent condensation in the dipleg and cause problems such as plugging due
to wet parti cul ate.
The ash container can be isolated by a slide-gate valve and emptied
during operation.
"Tornado" Cyclone
The secondary cyclone differs from the primary cyclone in its con-
struction and has a reported higher collection efficiency for fine particu-
lates. The body of the cyclone, rather than being refractory lined, is of
SS 310 and externally insulated. This construction method allows operation
to 927°C (1700°F) unless very high corrosion and erosion rates are acceptable.
Operations that encounter higher flue gas temperatures should bypass
this unit. The cyclone can be bypassed by opening the main damper valve in
the flue gas duct and closing the inlets to the cyclone.
3-40
-------
To operate the unit, flow adjustments have to be made to cause the
pressure drop between the secondary inlet and outlet duct to be 2.25 kPa
(9 inch H20) differential pressure. This establishes the required vortex in
the cyclone. The remaining flow is then introduced into the primary inlet.
The pressure and temperature measurements are indicated on the con-
trol console.
The dipleg configuration and service requirement are the same as
those for the primary cyclone.
Electrostatic Precipitator
The service and operation requirements of the electrostatic pre-
cipitator are minimal. To operate the unit the inlet and outlet duct has
to be connected and power applied to the unit from the control unit.
The plates of the ESP should be inspected after each run to insure that
they are clean and the bottom trap should be emptied.
Baghouse
The baghouse, a Young Model VM42-16, also requires very little service
and operating expertise. The hoses have to be connected and power and air
have to be supplied.
3
The dust collected in the bags is discharged into a 208 dm (55 gallon)
drum through a slide-gate valve. The drum can be exchanged during operation
with this feature.
The teflon bags supplied with the unit are rated for up to 232°C (450°F)
operation. An overtemperature and overpressure sensor indicate and warn the
operator if the maximum ratings are exceeded so that they can be corrected.
The equipment is further described in the manufacturer's literature.
The flue-gas ducting can be rerouted to permit the reconfiguration of
the facility to meet the needs of the test program.
3-41
-------
3.6 FLUE-GAS HEAT EXCHANGER AND SOOT-BLOWING LANCE OPERATION
The flue-gas heat exchanger's function 1s to cool the flue gases to 149
to 204°C (300°F to 400°F). The inlet gas temperatures may vary substantially as
well as the flowrates and a very high turndown ratio is required to accomplish
this. This flue-gas heat exchanger contains 10 heat exchanger modules that can
be individually brought on line. The design parallels that for the fluidized
bed comb ustor with the exception that these heat exchanger modules always
remain mounted. Flue gases are cooled as they pass through the maze of
bare tube from the top down. The operation of the heat exchanger requires,
therefore, that 10 heat exchangers be brought on line in sequence from the
top until the desired exit temperature is achieved. The bare tube design
allows for particles to be removed from the tubes by soot blowing. Coolant
outlet temperatures can be monitored on all modules and one measurement pro-
vides a bulk outlet temperature measurement. A second outlet temperature
sensor provides an alarm status light if the bulk temperature rises above 60°C
(140°F).
Coolant water flowrates are monitored by measuring orifice differential
pressure drops in the same fashion as for the fluidized bed. Since the heat
transfer coefficients are substantially lower here than in the bed, flashing
is not likely to be a severe problem. Flowrates can therefore be kept sub-
stantially lower than in the combustor bed. Each tube has a heat transfer
2 2
area of 0.060 m (0.64 ft ). The top base modules have five heat transfer tubes
whereas the remaining eight have nine tubes. Due to the highly varying flue gas
flowrates the outside heat transfer varies substantially. A 1.8 kg/tube
(four-Ibm/tube) flowrate appears to be sufficient to limit the temperature rise
to acceptable limits. Figure 3-4 may be used to set the flowrates. Verifica-
tions of the outlet temperature will confirm the requirement.
The flue gas contains particulate in the Sp-or-less category. Some of
this ash will deposit on the tubes and needs to be cleaned off periodically.
A manually operated soot-blowing lance can be inserted above and below the
bare tube heat exchangers. This task can be done while the unit is operating
or when it is shut down. An air jet is directed at the tubes cleaning them
^s the lance is moved in and out. The dust settles in the bottom ash pan or
3-42
-------
is carried into the baghouse or ESP. The ash pan can only be removed after a
run has been completed. Large dust accumulations on the tubes would indicate
ineffective heat transfer or a rise in the flue gas cooler outlet temperature
for no other apparent reason.
3.7 EMERGENCY SHUTDOWN
Should it ever become necessary to shut the system down due to an
emergency, the following control options exist.
All electrical power to the system is cut off by pushing the control
console power-off button. Coolant flow and the pneumatic transport air will
continue until shut off separately. If the failure is not due to a heat
exchanger tube failure it will be desirable to continue the coolant flow to
reduce the system temperature as quickly as possible.
To turn off the coolant flow and solid transport air flow close the
respective main valves.
When the power to the system is cut off the bed will be dumped.
3-43
-------
SECTION 4
FBC TEST RIG SAMPLING AND ANALYSIS
This section specifies the sampling and analysis techniques
recommended for application to the subscale fluidized bed coal combustion
(FBC) test rig. Many of the techniques and specific equipment suggested
represent "state of the art." That equipment which does not represent
state of the art, has been chosen to meet EPA's requirements of utility,
convenience, minimal expense and ease of operation. However, all decisions
were based on the following criteria:
Flexibility for a wide range of operating variables and
equipment configurations
Accuracy
Utility to minimize EPA manpower requirements
Certain "ground rules" were laid down by EPA with regard to the
sampling and analytical equipment. First, all analysis (with the
exception of online analysis instrumentation) is to be accomplished
offsite. Second, online analysis instruments are to be strictly limited
to those that are commonly available and straightforward in operation.
More complex measurements, such as those involving mass speetrometry or
gas chromatography, are required to be done offsite.
These ground rules have been strictly adhered to. Included in this
report is a tabulation of recommended analytical labs (Table 4-1)
4-1
-------
TABLE 4-1. SAMPLING SERVICES CONTRACTORS
Contractor
Home Location
Nearest Office
Acurex Corporation/
Aerotherm Division
Battelle Memorial
Institute
BETZ Environmental Eng.
George D. Clayton &
Associates
Commonwealth Laboratory,
Inc.
Engineering Science, Inc.
Enthopy Environmentalists
Environmental Science and
Engineering
Gilbert Associates
Midwest Research Institute
Monsanto Research
Corporation
Pacific Environmental
Services
Rossnagel Associates
Scott Research Laboratory
TRW Systems Group
York Research Corporation
Mountain View, CA
Columbus, OH
Plymouth Meeting, PA
Southfield, MI
Richmond, VA
McLean, VA
RTP, NC
Gainesville, FA
Philadelphia, PA
Kansas City, MO
Dayton, OH
Santa Monica, CA
Cherry Hill, NJ
Plumbsteadville, PA
Los Angeles, CA
Stamford, CT
RTP, NC
OH
PA
MI
Greenville, SC
VA
RTP, NC
FA
PA
MO
RTP, NC
CA
GA
PA
CA
CT
4-2
-------
including both institutional and private laboratories. Also included
(Table 4-2) is a list of recommended source sampling companies which could
provide support for the FBC test rig experiments. As a further aid the
APCA 1976 Consultant Guide, published in the APCA (Air Pollution Control
Association) Journal in July 1976, may be consulted.
The onsite sampling and analytical instruments chosen are capable
of continuously monitoring such pollutants as S0?, NO, NO , CO, C09,
£- A C.
02, low molecular weight reduced sulfur compounds, and light
hydrocarbons (C^ to Cg). Onsite continuous monitoring instrumentation
for the collection and analysis of low molecular weight reduced sulfur
compounds (H2$, RSH, RSR, etc.) is essential due to the high reactivity
of these species. This mode of analysis eliminates the transportation of
a large number of bulky samples and permits additional sample analysis if
problem areas become apparent during initial sampling.
The vast number of chemical and physical pollutant forms of
interest (Table 4-3 in Attachment No. 1 in the RFP) are impractical to
consider individually. Furthermore, many of them may be grouped and
considered as one species due to their similarity with regard to sampling
and/or analytical technique. Therefore, a pollutant species grouping
approach has been taken in this portion of the report. This approach does
not, however, preclude analysis for specific components. Table 4-4 is a
complete summary of sampling and analytical methods recommended for use
with the FBC test rig. Figure 4-1 is a flow diagram of the proposed FBC
test rig showing all sampling locations. Table 4-5 relates the sample
locations to their general sampling requirements. The gaseous and
particulate sample requirements referred to in Table 4-4 will be
4-3
-------
TABLE 4-2. POTENTIAL ANALYTICAL CONTRACTORS
Laboratory
Location
Battelle Memorial Institute
Commonwealth Laboratory, Inc.
Dow Chemical Interpreting Analytical Services
Environmental Services Associates, Inc.
Galbraith Microanalytical Laboratories
Gilbert Associates
Gulf Energy and Environmental Systems
LFE Environmental Analysis Laboratories
Langston Laboratories
Arthur D. Little
Midwest Research Institute
Monsanto Research Corporation
Research Triangle Institute
Southern Research Institute
Southwest Research Institute
Stanford Research Institute
TRW Systems Group
Columbus, OH
Richmond, VA
Midland, MI
Burlington, MA
Knoxville, TN
Philadelphia, PA
San Diego, CA
Oakland, CA
Kansas City, MO
Boston, MA
Kansas City, MO
Dayton, OH
RTP, NC
Birmingham, AL
San Antonio, TX
Palo Alto, CA
Los Angeles, CA
4-4
-------
TABLE 4-3. EXAMPLE LIST OF CHEMICAL AND PHYSICAL FORMS OF
POLLUTANTS OF CONCERN: POLLUTANT CHEMICAL FORMS
Sulfur Compounds
Elemental sulfur
Oxidized (sulfur dioxide, sulfur trioxide, sulfites, sulfates)
Reduced (hydrogen sulfide, carbonyl sulfide, sulfides,
disulfites)
Nitrogen Compounds
t Oxidized (nitric oxide, nitrogen dioxide, nitrates, nitrites)
0 Reduced (ammonia, cyanides, cyanates, hydrazines)
Organic Compounds
Hydrocarbons
-- Aliphatics
Olefins
-- Aromatics (benzene, toluene, xylene, etc.)
-- Polynuclear aromatic (benzo(a)pyrene, etc.)
Oxygenated Hydrocarbons
Acids (acetic, benzoic, etc.)
Anhydrides
Ketones
Epoxides
Ethers
-- Lactones
-- Phenols (crosols, xylenols, etc.)
4-5
-------
TABLE 4-3. Continued
-- Alcohols (methyl, etc.)
Peroxides
~ Polynuclear (oxa arenes, ring carbonyls)
Ozonides
Aldehydes (formaldehyde, etc.)
Halogenated Hydrocarbons
Chloronated, polychloronated
-- Fluorinated
Sulfur-containing Hydrocarbons
~ Mercaptans
Thiophenes
~ Heterocyclic/monocyclic (thio)
-- Polynuclear (thio arenes)
Alkyl sulfates
-- Sulfonic acids
SuIfoxides
Sulfones
Nitrogen-containing Hydrocarbons
Amines
-- Aliphatic
Aromatic (analines, naphthylamines, etc.)
~ Heterocyclic monocylcic (aziridines, pyridiries, pyrolles)
-- Nitro compoinds (Oimethylnitrosanrine, etc.)
Polynuclear
-- Aza arenes (acradene, etc.)
4-6
-------
TABLE 4-3. Continued
Organometallics (metal-containing hydrocarbons)
-- Metal carbonyls
-- Chelates
Sulfonates
Metal alkyls
Carbon Compounds
t Carbon
Carbon monoxide
t Carbon dioxide
Carbonates
Oxygen Compounds
Ozone
Halogen Compounds
Chlorides (HC1, etc.)
Fluorides (HF, etc.)
Hydrogen Compounds
Hydrogen ion (inorganic acids)
Trace Element Compounds
Arsenic compounds
Barium compounds
Beryllium compounds
Bismuth compounds
t Boron compounds
Cadmium compounds
Chromium compounds
4-7
-------
TABLE 4-3. Concluded
Cobalt compounds
Copper compounds
Fluorine compounds
t Gallium compounds
Germanium compounds
Lanthanum compounds
Lead compounds
Lithium compounds
Manganese compounds
Mercury compounds
Nickel compounds
Phosphorous compounds
Scandium compounds
Selenium compounds
t Strontium compounds
Tin compounds
t Vanadium compounds
Uranium compounds
Ytterbium compounds
Yttrium compounds
Zinc compounds
Zirconium compounds
4-8
-------
COAL
FEED
SYSTEM
SORBENT
FEED
SYSTEM
TRANSPORT
AIR
LOOP
FLUIDIZED
BED
COMBUSTOR
V.
r
FLUIOIZING
AIR LOOP
COMBUSTION PRODUCTS LOOP
PRIMARY
CYCLONE
-©
FGR LOOP
ELECTROSTATIC
PRECIPITATOR
BAGHOUSE
STACK
Q-0
5 I ASH >
* ' '
o-
Figure 4-1. FBC test rig sampling locations.
-------
TABLE 4-4. SAMPLING AND ANALYTICAL METHODS SUMMARY
Species
Swpllng Method
Analysis Method
Organic Compounds
Total light hydrocarbons
Separate light hydrocarbons
Middle to heavy hydrocarbons
(>C7)
NO/HOX
CO/CO,
Reduced sulfur compounds
(H2S, RSH, etc.)
SO,
Nitrates and nitrites
Sulfltes and sulfates
Reduced nitrogen compounds
(ammonia, cyanides, etc.)
Carbonates
Chlorides and fluorides
Hydrogen Ion (Inorganic acids)
Elemental sulfur
Carbon
Trace element compounds
Arsenic
Barium
Beryllium
Online analyzer
Online analyzer
SASS train XAD-2
sorbent trap
Online analyzer
Online analyzer
Online analyzer
Online analyzer
Online analyzer
SASS 1mp1ngers
SASS part leu late catch
SASS Impingers
SASS partleulate catch
SASS Impingers
NaOH absorption
SASS Impingers
SASS partleulate catch
SASS participate catch
SASS Impingers
(quartz probe)
Flame lonlzatlon Detection
(FID)
Gas chromatography with FID
Gas chromatography -
Mass spectrometry
Cheml luminescence
Nondlsperslve Infrared
Absorption (NOIR)
Coulemetrlc tltratlon or
Gas chromatography -
Flame photometric detection
Fluorescence
Electrochemical transducer
Calorlmetrlc or Specific Ion
Electrode (SIE)
Co1or1metr1c or SIE
Colorlmetrlc or SIE
Colorimetrfc or SIE
Colorlmetrlc or SIE
ph meter
Spark Source Mass
Spectrometry (SSMS)
ASTM D3178
Calorlmetrlc
Atomic Absorption Spectroscopy
(AAS)
AAS
T-913
4-10
-------
TABLE 4-4. Concluded
Species
Bismuth
Boron
Cadml urn
Chromium
Cobalt
Copper
Fluorine
Gallium
Germanium
Lanthanum
Lead
Lithium
Manganese
Mercury
Nickel
Phosphorous
Scandium
Selenium
Strontium
Tin
Vanadium
Uranium
Ytterbium
Yttrium
Zinc
Zirconium
Sampling Method
SASS impingers
(quartz probe)
Analysis Method
AAS
Colorimetric
AAS
AAS
AAS
AAS
SIE
AAS
AAS
AAS
AAS
AAS
AAS
Flame! ess Atomic Absorption
Spectroscopy
AAS
AAS
AAS
Colorimetric
Colorimetric
AAS
AAS
AAS
AAS
AAS
AAS
AAS
T-913
4-n
-------
TABLE 4-5. SAMPLING LOCATIONS AND REQUIREMENTS
Sampling Location
Sampling Requirements
A FBC coal feed
B FBC sorbent feed
C ~ Furnace bottom ash
D Primary cyclone inlet
E Primary cyclone ash
F ~ Primary cyclone outlet/
Aerodyne cyclone inlet
G Aerodyne cyclone ash
H Aerodyne cyclone outlet/
electrostatic precipitator
inlet
I -- Electrostatic precipitator ash
J Electrostatic precipitator
outlet/baghouse inlet
K ~ Baghouse ash
L Stack
Grab
Grab
Grab
Gaseous and particulate
Grab
Gaseous and particulate
Grab
Gaseous and particulate
Grab
Gaseous and particulate
Grab
Gaseous, particulate,
opacity
4-12
-------
accomplished either by continuous analyzers and one or any combination of
SASS trains located throughout the effluent system. The specific need
depends on the requirements of the research program.
Online Analysis Instrumentation
The following general remarks apply to all online sampling and
analysis monitors.
Each pollutant species of interest which lends itself to online
continuous monitoring, is capable of being measured with numerous
commercially available instruments (90 or more in some cases). In
addition, each family of instruments employs monitors using as many as ten
operational principles. As an example, NO-NO instruments number over
^
40. Their principles of operation include colorimetric, ion-selective
electrode, electrochemical cell, chemiluminescence, NDIR, nondispersive UV
and visible absorption, and absorption spectroscopy. Naturally,
instruments vary in price depending on various factors such as measurement
method, reliability and durability. In many cases it is necessary to
settle for less than maximum reliability (i.e., accuracy, specificity and
sensitivity) because of limitations in time available for inspection,
maintenance and repair that highly reliable instruments demand. This is
especially true in stationary source monitoring in which the operating
conditions may be quite hostile. However, this is not anticipated to be
the case with the FBC test rig.
Multiparameter capabilities are becoming a common attribute in
monitoring instrumentation. Use of such instruments offer .the advantage
of lower procurement, operational and maintenance costs compared with
using several individual monitors each with a single pollutant measuring
capability. However, due to the research-oriented nature of this task, it
4-13
-------
Is desirable to be able to simultaneously measure and record various
pollutant concentrations. This capability would enable researchers to
observe and analyze relative pollutant concentration fluctuations under
identical operating conditions. Consequently, separate instruments for
each pollutant species to be monitored are recommended.
All recommended monitors require a certain degree of sample
conditioning in which particles and moisture are removed before gases
enter into the instrument. In general, the system components are:
glass-fiber filters internal and external to the sampled flue, heat-traced
sample line, permeation drier for water removal, vacuum source, and
analytical instrumentation. Up to three monitors could use the same
conditioning unit. Figure 4-2 details a typical system. Table 4-6
summarizes pertinent facts regarding the online analyzers recommended.
As noted in Section 1, there are certain online sampling and
analysis instruments that are being strongly recommended for use on the
fluidized bed combustor test rig due to their ease of operation, low cost,
convenience and utility. The pollutants measured by these monitors are
sulfur dioxide (S02), nitric oxide (NO), nitrogen dioxide (N02),
carbon monoxide (CO), carbon dioxide (C02), oxygen (02), and low
molecular weight hydrocarbons (hydrocarbons
-------
Stack
Calibration
qases'
Air in
Parallel
permeation
or refrigeration
drier
Air out
1
Probe with
fiberqlass cylindrical
tube filters
Heated
sample
1 ine
Purge valve
Select valve
Pump
Vent
e
\
t
NO-NO
SO
X
°2
»
*
1
s .
J
s +
J *
\ '
Electrica"
sianal
Electrical
signal
Electrical
signal
\
Figure 4-2. Typical analyzer conditioning system.
4-15
-------
TABLE 4-6. ONLINE POLLUTANT ANALYZERS
Pollutant
co/co2
HO/NOX
so2
°2
Total hydrocarbons
«C6)
Reduced sulfur
compounds
(H2S, RSH, RSR,
etc.)
Manufacturer
Beckman
TECO
TECO
Teledyne
Beckman
Barton ITT
Model
865
IDA
40
326A
400
342
Principle of Operation
NDIR
Cheml luminescence
UV fluorescence
Electrochemical
transducer
Flame lonlzatlon
detection
Coul metric
tltratlon
Mu It 1 parameter
Capability
CO (Hexane, CO^,
S02, NO)
MO, NOX (03)
so2
°2
THC
H2S; RSH + H2S;
H2S + RSH + RSR
Measuring
Range
0.25 ppm - 100X
0.1 - 10,000 ppm
1 - 5000 ppm
0 - 10OT
0.02 ppm - 5X
0 - 1000 ppm
Approximate
Cost $
3000 to 4000
5000
6000
1400
2000
5000
£»
T-914
-------
Recording Sulfur Analyzer equipped with the Barton Model 302 Manual
Analytical Filter is recommended for onsite measurements of the following
sulfur compound groups: hydrogen sulfide; mercaptans and hydrogen
sulfide; and sulfides, mercaptans, and hydrogen sulfide. Thus, specific
determination can be made of H2$, mercaptans, sulfides, and residual
sulfur which includes sulfur dioxide. Included in the approximate base
price of $5000 is the titration module, electronic control modules, and
necessary accessories. A compatible external recorder is available for
approximately $1100.
If more specific identification and quantification of reduced
sulfur compounds is desired, an online, multicolumn, gas chromatograph
would have to be used. The best detector for this purpose is the flame
photometric type. A specific recommendation of which instrument is
preferable cannot be made until the research effort objectives are better
defined. Low molecular weight reduced sulfur compounds (such as H?S,
COS, RSH and RSSR) demand more complex online sampling and analysis
instrumentation. Anything other than online sampling and analysis is
precluded due to high reactivity.
co/co2
Carbon monoxide (CO) and carbon dioxide (CO,,) are best measured
by the principle of nondispersive infrared absorption (NDIR). NDIR is the
most commonly used method with its accuracy and dependability well
established since the early 1970's. However, NDIR instruments are subject
to interference from other gases, such as water and aromatics. The
problem is overcome by using auxiliary absorption cells or optical filters
which remove most of the radiation at wavelengths at which the interfering
substances absorb. Beckman Instruments' Model 865 is recommended for
4-17
-------
application on the F8C test rig. This unit is mainly used for CO detection
but it is also suitable for use in measuring CCL, hexane, SO- and NO.
However, minor modifications to the instrument become necessary for a
multiparameter capability. The need to have this capability cannot be
established until the research effort objectives are better defined.
so2_
Sulfur dioxide is best measured by Thermo Electron Corporation's
(TECO) Model 40 S02 Analyzer. The principle of operation is based on
the fluorescent emission of S02 molecules with ultraviolet light. The
electromagnetic radiation emitted is proportional to the SO-
concentration in the gas sample. The Model 40 is fully self-contained,
requiring no external gases or chemical for operation. There is, however,
a requirement for a gas conditioning system which removes condensible
water and filters particulate matter.
Total Light Hydrocarbons (Cfi)
Flame lonization Detection (FID) has widespread acceptance as the
best method for measurement of total light hydrocarbons (i.e.,
-------
NO. For the detection of N0x (NO + N02), conversion of N02 to NO is
required. N02 is recorded as the difference between the NO and NO
/\
measurements. The recommended Thermo Electron Corporation's Model 10A NO
to N0x Chemi luminescent Analyzer, has this N02 to NO conversion
capability. The unit is self-contained and requires only a few additional
items for operation. They are:
An 02 source (bottled 02 -- commercial purity)
NO calibration gas (no span or zero gas other than room air is
required)
A vacuum source (~2 scfh)
There are a number of adequate oxygen (02) analyzers on the
market. Acurex has experience with and recommends the Teledyne Model
326A, an excellent general-purpose 02 analyzer. The heart of the unit
is an 02 sensing cell. It is an electrochemical transducer requiring no
attention other than periodic replacement (approximately once each year).
Source Assessment Sampling System
The bulk of the FBC test rig pollutant sampling should be done
using the Source Assessment Sampling System (SASS). The capabilities of
this system are:
Measurement of particulate mass emission rate
Particulate sizing distribution into four size ranges (i.e.,>
10//m, 3f/m to lO^m, Ij/m to 3^m, and /m)
The collection of combined organic material
The collection of volatile inorganic matter
The collection of trace metals
4-19
-------
The (SASS) sampling train (Figure 4-3) is an extension of Acurex's High
Volume Stack Sampler (HVSS) and is considered to be the state of the art
in source samplers. All of the components in the HVSS train are found in
the SASS train with some important additions; they share the same probe,
sample lines, impinger system, vacuum source, and control module. The
SASS train has, in addition, particle size fractionating cyclones located
in the filter oven (immediately following the sample probe) and an XAD-2
sorbent trap module (Figure 4-4). The XAD-2 sorbent trap is a porous
polymer resin capable of adsorbing a broad range of organic species. It
is an integral part of the gas treatment system which comprises a gas
conditioner, XAD-2 sorbent trap, aqueous condensate collector, and
temperature controller. After adsorption of the organic species by the
XAD-2 sorbent trap, various organic fractions are desorbed by pentane
extraction in Soxhlet apparatus.
The SASS train will be an indispensable research tool in working on
the FBC test rig. Measuring the particulate fractional collection
efficiencies of the various control devices can be readily and accurately
performed with the SASS by simultaneously testing at the inlet and outlet
of the control device. In addition, from just one test run, data can be
collected regarding particle mass loadings and size distributions, and the
fate of both organic and inorganic species within the control equipment.
The analytical methods required for the samples collected in the
SASS train vary greatly in complexity and all are required to be done
offsite. The following paragraphs deal with those methods. See Figure
4-5 for the SASS sampling and analysis scheme.
4-20
-------
25-FOOT UMBILICAL LINE
OVEN WITH
CYCLONE
AND FILTER
IMPINGER TRAIN
AND ICE BATH
115V 15 AMP
POWER CORDS
CONTROL UNIT
25-FOOT SAMPLE HOSE
10 CFM VACUUM PUM
PUMP-CONTROL UNIT HOSE
-------
ro
CJ
9
Figure 4-4. Tenax module and vaporous trace element impinger train,
-------
tNJ
U1
Particulate
Matter
Source
*
Weigh in<
...
i II Morgan ics S(
SASS Train | _f n P'~
Conditioner' |_ Orr^nics fr
SASS Train f " A<
Impinger " ' | Inoi games Al
'* \ ] "L Ash ^Inorganics se
M Extraction 1 Organic*
_j 3-10u* j 1
1 -3 * r
I - jy* . same as above
.
Organic Pass through SASS
Material < C^ unaffected
.,.-> ,- - ,..., F*trartion _.
Malerla1>C6 absorber
Aliquot for
spectroscon"
,. .. , . , LC -Liquid chrom
iividual catches JR.. Infrared
r,CMS-r'as chroma to
Mass snectru
ements and
'lected anions
ysical separation into
actions LC/IH/MS
omic absorption
einents and
lected anions
vsical separation into
actions LC/IR/MS
,, . Aliquot for
rganics ^as cnroinatoqraphy
7 " 12 analysis
Oraanics Pnysica1 separation
organics 1ntQ fract1ons
12 LC/1R/GCMS
atoqraphy
i
rjranh N
n Ss
Figure 4-5. SASS train sampling and analysis.
-------
Partleu late Mass
The filter collection and residue left after rinsing and drying the
"front half (those exposed sample surfaces upstream of the filter) are
determined gravimetrically.
Particle Size Distribution
The particulate weight from each cyclone is determined
gravimetrically. Cumulative size distribution curves can be generated
from the cyclone and filter collections.
XAD-2 Sorbent Trap
As a first step, the XAD-2 sorbent material is homogenized and
physically separated into two portions. A 2-gram aliquot of one portion
is used in Parr bomb combustion over HNO^ to destroy all constituents
but inorganics. The inorganic components, including possible trace
elements, are then determined quantitatively by spark source mass
spectrometry (SSMS). The remaining portion of the sorbent is extracted
with pentane in a Soxhlet extractor. An aliquot of this organic
extraction is analyzed for C7 - C12 hydrocarbons by gas chromatography
(GC) using a flame ionization detector (FID). An infrared (IR) spectrum
is then obtained on the remaining organic extract. This enables
determination of which of the eight potential organic fractions are
present in the extract. This step saves unnecessary time spent on
analyzing for fractions that are not present.
The separate organic fractions are divided by subjecting the
extract to various solvents which exhibit an affinity for various organic
classes. Silica gel liquid chromatography (LC) is the technique used in
the separation procedure. Further identification of specific compounds
within each fraction is performed by infrared (IR) spectrometry. To
4-26
-------
quantify compounds identified in a particular fraction, the sample is
analyzed on a gas chromatograph-mass spectrometer (GC-MS).
2.1 LIQUIDS AND SOLIDS SAMPLING AND ANALYSIS
Solids
A complete and accurate material balance of the entire FBC test rig
system demands careful solids sampling of the coal/sorbent feeds and the
ash deposits from each control device. The sampling techniques, while
straightforward, must be done correctly to ensure a homogeneous
representative sample. Material size, consistency, and sample site vary
widely so one method is not appropriate for all samples.
Manual grab sampling is required in all instances. Coal and
sorbent can be sampled by taking four shovels from different locations in
the storage pile and homogenizing. If possible, a better practice
procedure is to take a shovelful of each feed material from the conveying
system. This is more desirable than storage pile sampling due to the
tendency in piles toward settling by particle size and density. A series
of such grab samples should be taken over a period of time. In either
case, a sample splitter should be used to reduce the size of the sample to
a manageable level and to assume that a representative sample has been
obtained.
Ash samples from the collectors are handled in much the same
manner. If ash hoppers are present, representative samples should be
taken periodically with either a pipe borer or auger sampler across the
width of the hopper (or in some cases, vertically down the hopper).
Samples collected should be stored in airtight, high-density
polyethylene containers until ready for analysis. Large samples should be
placed in metal containers lined with polyethylene bags.
4-27
-------
Coal, sorbent, and ash analytical methodology and equipment is
widely available. Coal and ash analyses and methods are listed in Table
4-7. Preferred sources are Commercial Testing and Engineering in Chicago
and Bituminous Coal Research in Washington.
Opacity Measurements
Opacity of the stack effluent gas has value as a relative
measurement tool when "tuning" the FBC for the cleanest emissions
visually. Two options are available:
Using a trained certified observer to read opacity using the
Ringelmann technique
0 Installation of an opacity monitor which could continuously
read and record smoke opacity. Numerous and comparable
commercial units are readily available
4-28
-------
TABLE 4-7. COAL AND ASH ANALYSES
Stream
Coal
Coal
Coal
Ash
from
bed
Analysis
Proximate
Ultimate
Size
Sulfur
Proximate
Trace
Size
Sample Producer
ASTM 02234
ASTM 02234
ASTM 0197
ASTM D197
Prep. Producer
ASTM D2013
ASTM D2013
Analysis
Moisture
Ash
Volatile Matter
Fixed Carbon
Overall
C, H
S
N
Ash
0
Moisture
Cl
Size
S
Trace Metals
Size
Analysis Procedure
ASTM 03173
ASTM 03174
ASTM 03175
ASTM 03172
ASTM 0271
ASTM 031 78
ASTM 03177
ASTM 03179
ASTM 03174
ASTM 03176
ASTM 03173
ASTM 02361
ASTM 0197-30
ASTM 01757 or
ASTM 0271
ASTM 02795
Section
ASTM 0197-30
T-915
-------
SECTION 5
TRAINING AND ACCEPTANCE TEST
To demonstrate the capabilities of the FBC test rig and its proper
performance within the design parameters, an acceptance test was conducted
upon completion of construction. Some minor operational problems were
encountered that have since been corrected.
Prior to the training and test subsystems had been inspected and
checked out to the extent practical, and the system had been operated by
several hands. The quality of workmanship, materials, and fabrication had
been verified to insure proper operation.
Training
A training program was conducted at the EPA's Research Triangle Park
facility in which representatives of the EPA and Acurex Corporation partici-
pated. The facility was discussed in detail with reference made to the
operations manual and the procedure outlined to derive a particular set of
operating conditions. On the following two days the facility was started
up, operated for several hours and shut down. On the second day of
operation the assigned laboratory technician was permitted under supervision
to operate the facility and gained sufficient confidence to operate the
facility by himself.
5-1
-------
Acceptance Test
Three tests were conducted to demonstrate
Startup, steady-state, and shutdown
Firing at design point
The operating range
Demonstration of Startup, Steady-State Operation and Shutdown
The facility was started up, operated and shut down as described in
Section 4 of this report. All systems performed as expected with the
exception of the solid feed system and the automatic bed height control.
The solid feed system pneumatic transport tube plugged several times
and the sorbent and coal feed was not steady, resulting in substantial
temperature fluctuations in the bed. The plugging of the pneumatic trans-
port line could be traced to some large (1.5 cm dia.) pieces of sorbent that
had not been removed by screening. The coal and sorbent also had a high
moisture content and this was the cause of the uneven feed. Dry, screened
material placed in the bin and run the next day substantially reduced these
problems.
The automatic bed height control gage signal lines were clogged dur-
ing the first test run and the solids dump valve could only be operated
manually. The lines were cleaned out and proper signals were recorded on
the second day. Due to the action of the bed, oscillations in the gage
readings required signal damping. Signal damping, however, also resulted
in slow response of the closing of the dump valve and substantial loss in
the bed height.
The bed height control has since been modified in its logic. Its
new timing contoller activates an alarm when the bed reaches a preset value
5-2
-------
before the valve is opened. Closing of the valve is set by a timer 2 to 10
seconds later. This sequence can also only be activated once every 6 to 10
minutes.
The ash dump valve will also be opened upon a power failure in the
Wing G facility to prevent fusing of the bed.
An air supply line to the valve burned through when a hot piece of
sorbent sprayed on the line. This line was replaced with a copper tube.
Demonstration Firing at Design Point
Operation at a constant coal feed rate and bed temperature is
vertical to obtain meaningful data when samples are withdrawn from the
stack or other parts of the system.
The performance of the FBC test rig to operate at approximately
32 kg/hr (70 Ibs/hr) and 873°C (1600°F) was relatively satisfactory within
a +_ 17°C (25°F) temperature band. Closer control would require the use of
an automatic temperature feedback control on the coal feedrate.
It is noted here that the energy capacitance of the bed is small and
that small variations in the coal feedrate (> 1%) will have larger effects
on the temperature variation than the +_ 14°C (+_ 25°F) fluctuations observed.
The particle size of the coal sorbent and the moisture content influence the
feedrate and energy release rate due to bulk density variations and the
latent heat of vaporization of water. Since these variables are very dif-
ficult to control or even undesirable to control, effective control can only
be achieved by controlling the secondary effects, namely temperature in the
bed. A dual set point controller lowering or raising the voltage for the
coal feeder would accomplish this at a relatively low cost should this
be desirable.
5-3
-------
To increase the resolution on the solid feed rate controllers
additional rheostats have also been installed to control the span.
Further test operations to date have shown the coal feed rtae to be
accurately controllable and plugging with well screened material to be no
problem.
Demonstration of Operating Range
Operation of the FBC test rig over its entire operating range within
acceptable component operating conditions is only possible by reconfiguring
the facility. Whether the facility can achieve all of the operating con-
ditions specified can however be inferred if a judicious set of operating
variables is selected and observed. The critical operating parameters that
needed to be observed were maximum air, coal and sorbent flowrate and the
maximum combustor temperature. The maximum air flow capability was verified
when the system was started up to preheat the bed. Coal and sorbent flow-
rates had been verified before testing began and the bed was operated,
although only for short durations up to 1050°C (1925°F). Since essentially
zero flow can be achieved by all solids flows the limiting factor is the
minimum flow through the blower. Pulsations in the blower have been
observed only below the minimum required flow to meet all specified operat-
ing conditions.
In conclusion, the demonstration test showed that the operating
condition specified in the statement of work can all be met although not
all at the same time or in the same test rig configuration. Minor operating
problems have been corrected. Certain procedures must be observed to insure
stable, reliable solids feed system operation.
5-4
-------
SECTION 6
RAW MATERIALS SOURCES, HANDLING, AND PRICES
Coal Selection
Since changes in coal properties have marked effects on the combus-
tion process and on pollutant emissions, and since coal properties vary sig-
nificantly from coal type, the testing of several different coals is essential
to a good test program and to the understanding of combustion in the FBC.
Important properties of interest include:
t Fuel nitrogen content, which is expected to have an important
effect on FBC NO emissions and on NO control techniques (as it
^ ^
does in conventional combustors)
Fuel sulfur, the retention of which by bed or fuel additives is
usually a major goal, so that a study of the retention effective-
ness of various additives for various coals is a primary part of
most research programs; here it may be necessary to distinguish
pyritic sulfur from organically bound sulfur
0 Ash content which influences flyash amounts and ash retention
Ash properties, such as fusion temperatures and chemical consti-
tuents, which affect ash retention and combustion properties.
t Other coal composition parameters, especially contents of alkali
metals and trace metals, and acid base ratios, which influence
fouling and corrosion
General coal properties such as rank, volatiles content and heating
value, which influence combustion behavior and ash retention
The selection of coals, however, cannot depend only on a "scientific" interest
in the effects of property variations, particularly in a research program of
specific objectives and limited scope, since the number of properties and effects
6-1
-------
to be studied 1s very large. Research programs 1n the FBC facility must con-
centrate on coals of present or future Importance In the power production and
Industrial steam raising markets. This limits choices to three generic market
types, each with reasonable restricted ranges of variation 1n properties.
Appalachian Region High-Volatile Bituminous - coals in this class
represent the single most used steam-raising coals In the United
States and are generally regarded as the finest for conventional
combustion techniques; substantial production Increases are expec-
ted; this coal dominates Eastern markets.
Interior Province, Eastern Region Bituminous this coal dominates
the Midwestern market area of the United States and 1s prominent
in steam-raising applications.
Northern Plains Province Subb1tum1nous economically the most
attractive Western coal with substantial reserves; It has already
achieved large market radius; substantial production increases
are expected; It provides a low sulfur type.
To this list we added a lignite, which has a large market potential and re-
presents an interesting h1gh-ash, low-quality limit.
Table 6-1 briefly describes these four coals, presents the rationale
for selecting each type, and identifies individual sources of supply and coal
cost.
6-2
-------
TABLE 6-1. SUMMARY OF SELECTED COALS
Class
Appalachian Hlgh-
Volatlle Bltuwl-
nous
Interior Province
(High- I Medluw-
Volatlle
BUimlnous)
Mountain Province
SubbltuMlnous
Mountain Province
Lignite
Type
PUtsburg Sean
IB (high-
volatile
bituminous)
Kentucky 19
Western Kentucky
Montana Subbltu-
Inous Power
River Region
N. Dakota
Lignite
Source
Consolidation Coal
PUtsburg. E. Reich!
V.P. Research,
(412) 288-8700
Pea body Coal Co.,
0. Shelton, Hgr.,
M. Region. St. Louts
(314) 342-3400
Peabody Coal Co.»
0. Shelton, Hgr.,
W. Region, St. Louis
(314) 342-3400
Consolidation Coal
Co.. Western Dlv.
Velva Mine, Velva
N. Dakota
(303) 534-2100
Vol
38-40
30-42
44
43
PC
50-57
45-54
46
48
Typlca
ASH
5-8
7-12
9
9
1 Propertle
HV
13.4-14K
10-12*
B.6K
6.8K
1
S
1.5-4.5
2-5
1.0
0.5
N
1.3-1.8
1.2-1.8
1.0
Rationale
Highest Quality U.S.
Coal; Wide Distribu-
tion and Future Ex-
panded Production,
High Sulfur, Highly
Caking
In General Similar to
Appalachian Coal;
Widely Distributed;
Especially In Midwest-
ern State; High Sulfur,
Noncaklng
Increasing Distribu-
tion; Very Abundant;
Expected to be Even
More Available. LoM
In Sulfur; Noncaklng
High Ash Content; Lou
Heating Value; Low
Sulfur; Noncaklng
I/ton*
$26.50
$25. 75
$ 9.75
$ 6.05
en
i
CO
*Cost refers to FOB mint and Includes state sovereign tax
-------
Coal Transport. Pulverization, and Storage
The four coals can be transported by rail 1n bottom dump cars from
the respective mines to Cincinnati, Ohio for grinding by H111 and Griffith,
Inc.3
Table 6-2 shows the railroads that have offered to transport the coal
to Cincinnati, and the cost for each respective transport. H111 and Griffith
has expressed reservations about grinding lignite with their equipment. This
problem can be avoided by grinding this high ash content coal at Smith Facing
in Cleveland, Ohio.
Coal Type Grinding Company Cost
Pittsburgh 18 H111 and Griffith
Kentucky 19 Cincinnati, Ohio $65/ton
Montana Subbltuminous (513) 921-1075
North Dakota Lignite Smith Facing
Cleveland, Ohio $60/ton
(216) 861-6040
The cost includes pulverization, bagging, and palletization. Because
grinding does not include screening of the coal, a mixture of different size
coal 1s obtained. This mixture usually consists of:
4 to 6 percent - 20 mesh
20 to 25 percent - 60 mesh
35 to 55 percent - 100 mesh
15 to 40 percent - 200 mesh
Aerotherm experience on similar programs Indicates that the selection of the
pulverizer subcontractor 1s critical. Very few firms are prepared to handle
research amounts of widely varying coals In the careful and scientific
manner required by a research program. Hill and Griffith appears to represent
the best selection from a very large number of firms considered in a multi-
state region 1n the neighborhood of Raleigh-Durham and of most of the coal
supply.
6-4
-------
TABLE 6-2. COAL TRANSPORTATION COSTS FROM MINE TO CINCINNATI
i
en
Minimum Load
Tons
60
60
60
25
Coal Type
PUtsburg #8
Kentucky#9
Montana
Subb1tum1nous
North Dakota
Lignite
Railroad
Monogahela
Illinois Central
Gulf
Burlington Northern
Soo Line
Mine Location
Fa1rv1ew, W.V.A.
Ohio County, KY
Fordsvllle
Col strip, MN
Velva, NO
Total
Cost
$
585
500
3,630*
1 ,245b
Three routes Col strip MN
Minneapolis
Chicago
Minneapolis
Chicago
Cincinnati
$35.41/ton
$14.067ton
$11.01/ton
}C1an note = $49.80/ton
-------
A screening process permits uniform derived size of the pulverized
coal, but adds significantly to pulverization costs because of time Involved
and coal wastage. Bagged coal would be transported to Raleigh-Durham by
truck at about $36 per ton.
The Indicated tonnage of coal supply represents nominally a 2- to
4-year supply at expected testing schedules. If less than this turns
out to be required, a modest amount of Improvisation usually succeeds 1n
selling the excess, either to the pulverization firm or to local users.
Sorbent Selection, Pulverization, and Storage
The following criteria Influence the choice of sorbent stone:
Acceptable properties for sulfur removal
Attrition resistance
t Trace element emission characteristics
Regeneration characteristics
Suitability of spent sorbent for final processing and disposal
t Economic availability of the stone
Fluid1zed-bed experimentation and modeling has attempted to develop
quantitative guidelines for these criteria, relating these guidelines to
properties of the stone and to combustion and heat transfer conditions 1n
the fluidlzed bed. The results to date provide no definitive Information,
however, and give very little practical guidance In stone selection. For
sulfur capture, limestone 1s generally more effective than dolomite at 1
atmosphere, and partial or total calcining appears to be helpful In most
cases. (For pressures greater than 1 atmosphere, calcining appears
required for limestone and very useful for dolomite 1n most, but not all,
cases.) For the other criteria above, essentially no consistent guidance Is
available.
For costing purposes, therefore, we select a single limestone and a
single dolomite, both of which have been extensively tested In earlier
programs: Limestone 1359 and Dolomite 1357. Table 6-3 gives relevant
properties. Due to their different calcium content, each has a different
6-6
-------
TABLE 6-3. TYPICAL ANALYSES OF LIMESTONES AND DOLOMITES
Component
CaO
MgO
H20 + C02
S102
FC2°3
S03
Total
Composition %
Dolomite
1337
28.9
22.9
47.4
0.5
0.2
99.9
U.K. Dolomite
29.3
21.5
46.3
0.1
97.2
Limestone
18
45.7
1.4
36.6
13.6
0.3
97.6
Limestone
1359
55.7
0.3
43.6
0.5
0.1
100.2
U.K. Limestone
55.4
0.3
43.5
0.7
0.1
_...
99.8
The sources of those materials were:
Limestone 18: Supplied by Fuller Industries Inc., Fort Meyers, Florida. This has been referred
to as "U.S. Limestone No. 18" or "T. 18" 1n Interim reports.
Limestone 1359; Supplied by M. J. Grove Lime Co., Stephens City, Virginia and prepared at the
Argonne National Laboratory. This has been referred to as "Argonne" limestone or "Limestone 1359"
1n Interim reports.
U.K. Limestone; Supplied by J. Gregory & Sons, Kldsgrove, Stoke-on-Trent.
U.S. Dolomite 1337; Supplied by Charles Pfizer 4 Co., Glbonsburg, Ohio.
U. K. Dolomite: Supplied by Steetly (Manufacturing) Ltd., Worksop, Notts.
-------
effect on sulfur oxide retention. Table 6-4 shows absorbent sources with
cost of product and cost of shipping. The dolomite sorbent, low calcium
content, can be furnished 1n three sizes. The cost of pulverized size,
50 to 55 percent, 200 mesh has been reported In the table. The sorbent will
be bagged for storage and shipped to Raleigh-Durham, North Carolina, by
Charles Pfizer and Company. The limestone sorbent 1s supplied by Grove
Lime Company 1n 95 percent, 100-mesh size, but transport would have to be
made 1n an enclosed truck, since the limestone Is not bagged. Bagging the
limestone will bring the price to approximately $50/ton. Larger size lime-
stone (0.16 to 0.32 cm (1/16 to 1/8 inch)), bagged, will cost as much as
$100/ton, because it requires screening to obtain a uniform size. Freight
cost of bulk material will be on a minimum of 20 tons transport; therefore the
freight cost will be $400.
Calcining or other pretreatment should be handled by EPA or the
research program contractor to assure appropriate control and characteriza-
tion.
6-8
-------
TABLE 6-4. SOURCE AND COST OF SORBENT MATERIALS
Absorbent
Source
Cost
Freight to N.C.
Dolomite 1337
Limestone 1359
Charles Pfizer & Co.
Gibsonburg, OH
(419) 637-2101
M.J. Grove L1me Co.
Stephen City, VA
(703) 869-2700
(301) 662-1181
$17.78/tona
for first
8 tons
$5.00/tonb
-$30/ton
$20/ton
Includes cost of bagging and pelletlzlng
Bulk not bagged
6-9
-------
SECTION 7
SAMPLING SUPPORT FEATURES
The basic purpose of the FBC test rig is to evaluate the effect of
changes in operating conditions on emissions. To permit sampling at
significant locations, 3-inch ports are provided at the locations noted in
Figure 7-1 for the purpose elaborated in Table 7-1.
7-1
-------
-J
I
ro
COAL
FEED
SYSTEM
SOftBENT
SORBENT
FEED
SYSTEM
TRMSPMT
AIR
LOOT
COMMESSOft
HUlOUtO
BCD
CQWUSTM
©-
FLUID1ZIN6
AIR LOOP
FLUIDIZIM
AIR
MEHEATER
[ SLOMER |
SILENCER
COMBUSTION PRODUCTS LOOP
-------
TABLE 7-1. SAMPLING LOCATIONS AND REQUIREMENTS
Sampling Location
Sampling Requirements
A Furnace coal feed
B - Furnace sorbent feed
C Furnace bottom ash
D - Primary cyclone Inlet
E - Primary cyclone ash
F - Primary cyclone outlet/
Aerodyne cyclone Inlet
G - Aerodyne cyclone ash
H - Aerodyne cyclone outlet/
electrostatic precipitator
Inlet
I - Electrostatic precipitator
J Electrostatic precipitator
outlet/baghouse Inlet
K - Baghouse ash
L - Stack
Grab
Grab
Grab
Gaseous and parti oil ate
Grab
Gaseous and particulate
Grab
Gaseous and particulate
Grab
Gaseous and particulate
Grab
Gaseous, particulate,
opacity
7-3
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
. REPORT NO.
EPA-600/7-78-166
3. RECIPIENT'S ACCESSION-NO.
4. T.TLE AND SUBTITLE Design and Construction of a Fluidized-
bed Combustion Sampling and Analytical Test Rig
5. REPORT DATE
August 1978
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
H. Dehne
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Acurex Corporation/Energy and Environmental Division
485 Clyde Avenue
Mountain View, California 94042
10. PROGRAM ELEMENT NO.
EHE623A
11. CONTRACT/GRANT NO.
68-02-2170
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
13. TYPE OF REPORT ANC
Final; 8/76-4/78
14. SPONSORING AGENCY CODE
EPA/600/13
is. SUPPLEMENTARY NOTES jERL-RTP project officer is John H. Wasser, Mail Drop 65, 919/
541-2476.
. ABSTRACT
report describes the design, construction, and installation of a
fluidized-bed coal combustion sampling and analytical test rig in the High Bay Area
(Wing G) of EPA's Industrial Environmental Research Laboratory (IERL), Research
Triangle Park, North Carolina. The rig, to be used by IERL to investigate the
emission characteristics of fluidized-bed combustors, was designed for maximum
flexibility, accuracy, and utility. System operating ranges are: coal feedrate 10 to
50 kg/hr; sorbent feedrate zero to 25 kg/hr; excess air 10 to 300%; bed temperature
750 to 1100 C; and fluidizing velocity 1 to 5 mps. The program included four phases:
conceptual design; final design; purchase, fabrication, and installation; and checkout,
testing, and documentation. After installation, an acceptance test demonstrated that
the system had been completed in accordance with the approved design, and that all
equipment was properly installed and corrected to serve its intended purpose.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Croup
Pollution
Fluidized Bed Processors
Fluidized Bed Processing
Test Equipment
Sampling
Analyzing
Coal
Pollution Control
Stationary Sources
13B
07A
13H
14B
2 ID
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
156
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
7-4
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