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Electric Utility Baghouse
Specification
Client Electric Utility
Description In
a recent contract we provided a utility client with a design package that
included items such as materials of construction, insulation and access
requirements, bag cleaning system components, damper requirements, fabric
specification, G/C ratio, fabric type, bag and cage specification, bag spacing,
number of modules, etc. This design specification was incorporated into
the client's procurement package. We then assisted the client in the
subsequent procurement process by providing proposal review and commentary.
Coal-Fired Boiler Bag Specification
Client Utility Client
Description ETS was retained by a utility client to improve the performance of their
pulse jet baghouse. The operation was plagued with premature bag
failure. ETS concluded that the underlying cause of the problems was
an uneven distribution of the gas. This maldistribution results in
very high localized velocities which rapidly erodes the bags. We
designed a modification to the inlet gas plenum which solved the uneven
distribution and thus bag wear. The modifications were made and the
system has since experienced improved bag life and significantly lower
operating costs.
Consulting
and Engineering Program for Steel Mill
Client Inland
Steel - Harbor Works
Description ETS was contracted
to execute a major consulting and engineering program for Inland Steel
- Harbor Works coal pulverizing facility to assess the pulverized coal
injection emission control system for a large (10,000 molten tons/day)
blast furnace. The work scope entailed a detailed baghouse and emission
control assessment, an engineering feasibility study of repairing and/or
replacing the emission control system, and options for that design. ETS
was responsible for sizing and specifying the system hardware, including
two 70,000-acfm cyclone precleaners, screw conveyors, and supporting equipment
that was to be engineered into the existing system. The work scope also
included various conceptual baghouse/cyclone designs (including costs),
conveying capacity analysis, system sizing, connecting ductwork and explosion
vent sizing, calculating structural steel loads, structural steel design,
and selecting and developing the instrumentation to ensure reliable system
operations. ETS also assisted in system start-up and troubleshooting.
Reverse Air Baghouse System EvaluationClient Utility Company - Electrical Generating
Description ETS was contracted
by a major utility to conduct an inspection of the fabric filter system located
in one of their facilities in central Pennsylvania. The baghouse
had been in service for many years and had a history of operation at lower than
design inlet gas temperatures (sub acid dew point) due to frequent low boiler
load conditions and other operational problems. Utility personnel were
concerned about the overall condition of the system and requested inputs so that
they could make decisions about extending its length of service versus
purchasing new equipment. They also expressed concerns over a high rate of
bag failures, high pressure drop across the bags, and corrosion related failures
in several specific areas of the baghouse, inlet ductwork, and the penthouse
gallery.
The ETS work scope called for conducting external and internal inspections of
the baghouse system including the inlet and outlet ductwork, inlet and outlet
turning vanes, system control panels and component monitoring instrumentation,
all baghouse compartments and all associated equipment including bags and bag
tensioning systems, tube sheets and thimbles, access doors and gaskets, all
compartment flow dampers (inlet, outlet, reverse air, and relief), reverse air
manifolds, baghouse hoppers and dampers, and the baghouse penthouse.
The inspection identified several problems; among them was improper bag
tensioning practices, outdated controls and broken component monitoring
instrumentation, eroded inlet turning vanes, several malfunctioning dampers,
etc. In addition the back section of the inlet ducting was almost
completely plugged with fly ash that had accumulated over the years. It
was our concern that this accumulation restricted gas flow to the last few
compartments of the baghouse, causing a system flow imbalance, thus having a
negative impact on bag life, emissions and pressure drop. There was
evidence of acid condensation on the internal walls of the outlet and reverse
air ductwork, however there appeared to be very little or no loss of metal in
these areas. In general the physical integrity of the baghouse and its
connecting ductwork was in good condition, considering the age of the system and
its history of operating at low inlet gas temperatures.
After conducting the inspection ETS
provided an inspection report listing all observations, concerns, and commentary
on the condition of the equipment. The report also included a list of
items that should be addressed. The list was prioritized based on a
perceived return on investment (ROI) starting with the best ROI and ending with
the least ROI. The report also included ETS recommendations for equipment
restorations and O&M procedures that would not only improve baghouse operations
but enable the system to operate for at least ten additional years. The
initial ETS inspection took place in 2001. In 2007 ETS was requested to
conduct a follow-up inspection to determine the status of the system and monitor
the effect that the actions taken in follow up to our original report had on the
condition and operational reliability of the system. While the control
panel has not yet been updated, most of the other recommendations were acted
upon. It was reported that removing the ash in the inlet duct and
replacing the turning vanes had resulted in improved flow distribution across
the system, bag life had improved and the system has been operating reliably,
even though the baghouse system sees frequent dew point excursions because of
operational upsets such as boiler tube leaks and continual swinging of load
levels.
Develop Preventive Maintenance Plan and
Manual
Client Railroad
Company Industrial Boiler Baghouse
Description ETS was hired
by an eastern based railroad company to develop a Preventive Maintenance (PM)
plan for the air pollution control system (APC) serving three stoker boilers at
one of their work facilities in Pennsylvania. Each boiler was followed by
its own mechanical collector, the flue gases were then directed to a common
reverse air baghouse, an ID fan, and stack. A dry acid gas removal reactor
was expected to be installed just prior to the baghouse in the future.
The purpose of the PM plan and its
accompanying PM manual was to fulfill state air pollution MACT permit
requirements and to formalize the current PM practices that have produced
acceptable APC operation and performance and to maintain optimum operating
parameters for the APC system. An additional benefit of the manual was to
provide an aid in training of new operations and maintenance (O&M) personnel
assigned to the baghouse and associated APC equipment.
This preventive maintenance manual
was to provide direction to the maintenance department by monitoring and
documenting maintenance of the equipment. A systematic walk through by a
qualified mechanic checking equipment parameters and operating conditions, and
noting any unusual visual or audible conditions, can be very effective if done
on a regular basis. These scheduled PM inspections were to insure that the
baghouse equipment was operating properly; to insure proper and timely
maintenance; to provide audible and visual checks to detect abnormal equipment
operation; and to assist in scheduling regular maintenance and repairs to
eliminate downtime. The manual represented a recommended preventive
maintenance plan. It identified the parameters that needed to be
monitored, how frequently, and the level of personnel assigned to the task.
It also provided expected parameter ranges and what actions should be taken if
the parameter reading fell outside that range.
The PM plan was implemented by the
facility in 2007 and a subsequent plan was developed by ETS for a second
facility in 2008.
Baghouse System Design Consultation
Client Electric
Utility
Description A prominent
Virginia based utility company retained ETS, Inc. to assist them in the design
and specification of a new fabric filter system for the client's generating
plant in the eastern portion of the state. The initial ETS task was to
develop a techno-economic comparison of an ESP, a reverse-air fabric filter system,
and a pulse-jet fabric filter system. This effort included comparative
analysis of different fabrics and two different gas-to-cloth (G/C) ratios for
each baghouse type. Space requirements for all three devices were estimated and
comparative capital and operating costs were developed using methodology
detailed in the EPA OAPQS Control Cost Manual. In addition ETS addressed
current and future fine particulate emission and their impact on evaluated
technologies.
In this case the pulse-jet was the
recommended approach; the client embraced the recommendation and requested that
ETS develop a baghouse system specification. This flange-to-flange (inlet
to outlet) design included all baghouse items including, baghouse and hopper
materials of construction, baghouse insulation and access requirements, bag
cleaning system components, damper requirements, fabric specification, G/C
ratio, bag and cage dimensions and specification, bag spacing, and number of bag
modules. Additional details addressed were gas distribution modeling and
requirements, baghouse instrumentation and monitoring requirements, and
performance guarantees such as pressure drop (expected and maximum), bag life,
and outlet emission requirements. The design also established vendor
experience criteria as well as listing suggested general and technical
requirements that would be relevant to final design and subsequent operation of
the baghouse.
The design specification was
reviewed, and the client's management team decided to incorporate the ETS design
into a final design specification that would be incorporated in a procurement
package. ETS provided technical oversight in the development of the final
design package. We then assisted the client in the subsequent procurement
process, including vendor interviews and selection.
Baghouse
Design
Client Great
Wall Iron Works, Taiwan
Description Three
new residual oil fired boilers were to be installed at a brewery contracted
by Great Wall Iron Works. The boilers were to be equipped with limestone
injection systems to reduce sulfur dioxide emissions, and the resulting
high particulate emissions required the addition of particulate controls.
Each boiler would operate eight hours per day, exhaust 36,000 acfm at 385°F
with a 480 ppm SO2 concentration, and require 99.5% particulate removal
to meet local emission standards. Because of very limited space for emission
control equipment, a custom-designed baghouse was needed, and a major metal
fabrication facility in Taiwan was retained. In order to obtain the expertise
needed to design the baghouse for this relatively unique application, ETS
was retained by the fabricator.
Because of the space constraints, ETS chose a pulse-jet
baghouse design with five independent filter modules; provisions were made
for both off-line and on-line cleaning. Off-line cleaning was recommended
to enhance removal from the bags of potentially sticky particulates resulting
from incomplete oil combustion. The high exhaust temperature and SO2 content,
combined with the daily start-up and shut-down cycle, meant that the filter
bags had to be designed to withstand temperature extremes and possible
acid attack, in addition to the stresses generated by the pulse-jet cleaning
system. Several filter fabric options including acid resistant woven and
felted fiberglass, aromatic polyimide (P84) and polyphenelyne sulfide (PPS)
were provided to the client.
ETS completed the total design of the baghouses and their
support structures, and provided detailed fabrication drawings for every
aspect of construction of the baghouse. Both the design and the drawing
processes were greatly facilitated by the use of computer-aided design
techniques. ETS also provided specifications for the baghouse components
that would not be fabricated, such as the filter bags/cages, inlet and
outlet dampers, air compressor, and the dust removal system. Additionally,
ETS designed the baghouse control systems and provided drawings and component
specifications for their assembly and operation. Finally, ETS also provided
supporting manuals describing operation and maintenance procedures specific
to this application.
VOC Control
System Specification
Client Midwest
Furniture Manufacturer
Description ETS was contracted
by a large furniture manufacturer in the midwest to research and specify
the best-suited VOC emission control system for their operation. ETS had
previously consulted with this company to resolve a notice of violation
(NOV) for VOC emissions with State and USEPA officials. This client had
neglected to obtain an air permit to construct and operate their three
year old plant (which is the reason they wish to remain anonymous). ETS
was able to successfully negotiate an agreement with the regulators and
avoid fines and significant operating limitations. Using stack test data
and mass balance data, ETS was charged with performing the following tasks:
Removal
of Dust-Collection System at a Tire Retread Facility
Client Bandag
Incorporated
Description ETS was retained
by Bandag, Inc. to conduct an engineering evaluation on its Tread Grinding
Dust Collection System and to identify and design a system that would improve
dust pickup at the buffing stations, and at the same time reduce the potential
for fires in the system baghouse. The engineering evaluation of the existing
dust collection system included the following:
- Buffer station gas volume measurements and experiments
to determine the gas volume that provides satisfactory dust pickup
- Determination of baghouse inlet dust loading, gas volume,
static pressure, and dust particle size distributions
- Ductwork structural evaluation
- Baghouse structural evaluation
- System fan evaluation and analysis of various upgrade/replacement
options.
Ultimately, ETS outlined specifications to describe the
general qualities, performance, and basic systems required in the fabrication
and construction of the finishing line modification. The system modification
involved replacing an existing spark arrestor with a medium-low energy
cyclone, replacing the existing fan with a larger fan with improved system
entry, and recommending fabric types to provide superior resistance to
burning with Hysil used as a precoat. Included in the specifications were
identification of all labor, materials, equipment, tools, supplies, taxes,
and services required for construction activities, such as:
- Demolition and removal of existing ductwork from above
buffing hoods to baghouses, including spark arrestor boxes and ductwork
support
- Demolition and removal of ductwork from baghouses to
fans and fan discharge duct
- Constructing two foundations and making roof penetrations
for two new columns
- Installing new structural steel platform framing in cyclone
area
- Removing fans and motors
- Removing platform and decking handrail
- Installing new motor and fan support framing and deck
extension framing.
Turnkey
Dust Handling and Control System
Client Boxley
Quarries
Description ETS was retained
by a large rock quarry operation to design a turnkey crushed stone transfer
and air pollution control system. The work scope included design, specification,
fabrication and installation of appropriate screw conveyors, belt conveyors,
dust supression systems and a 25,000 acfm fabric filter control system.
This system allowed the client to meet the federal and state air pollution
standards for both point source and ambient dust.
Obtain
Permit to Construct and Operate
Client Anonymous
Concrete Manufacturer
Description ETS was retained
by a national concrete and polymer concrete manufacturer to obtain state
permits to construct and operate a polymer concrete plant after the fact.
An initial background study of the case revealed that the plant had been
operating for two years without a permit. The obvious task was to obtain
an operating permit and bring this source into compliance.
To accomplish this, ETS did the following:
- Performed EPA emission tests for particulate and volatile
organic compounds
- Performed the necessary input-output calculations to
determine air pollutant emissions from the plant stacks not tested
- Acted as liaison between the state Air Pollution Control
Board and the client, including representing client during meetings with
state
- Completed proper state permit forms to construct and
operate the source.
Assessment
of an Air Pollution Control Technique Serving a Complex Chemical Process
Client E.
I. DuPont de Nemours & Company, Inc.
Description ETS
was retained by a major chemical company to assess the air pollution control
equipment of a catalyst production process. The system was plagued with
visible emissions and was a constant source of complaints from local enforcement
agencies. A program was agreed upon that included the following main tasks:
- Problem definition and profile of emission chemistry.
- Selection of alternative control techniques.
- Specific recommendations - including equipment specification
and recommended operation.
The project was a success due to ETS's ability to first
define the problem and then apply basic chemical engineering principles.
ETS recommended a solution to achieve the program goals.
Baghouse
System Upgrade
Client Kerr
Industries
Description The fabric
finishing division of this Fortune 500 company had a baghouse operating
on a coal-fired boiler. ETS was involved in upgrading the overall capability
of the baghouse system. This application had been plagued with high system
pressure drop. The causes for excessive pressure drop were numerous, including
insufficient bag cleaning, poor coal quality, improper boiler operation,
and, at full load conditions, excessive gas-to-cloth ratio. Improvements
were made to the cleaning system and alternate fabrics were screened to
determine their capability to operate effectively at extremely high gas-to-cloth
ratios (>8:1). Tremendous improvements were made and the system in now
able to operate at full boiler load conditions.
Engineering
Evaluation, Testing, and Expert Witness
Client Anonymous
Description ETS was retained
as an expert witness by a major steel manufacturer for problem assessment
and testimony. The client was operating a pulse jet baghouse for control
of particulate emissions from an electric arc furnace. The system was designed
to handle 100,000 acfm, but due to excessive pressure drop could handle
no more than 80,000 acfm. To date, ETS has researched this problem, including
conducting a detailed data and inspection review, an engineering evaluation
with economic analyses, and issuance of a report discussing the problem
assessment and solutions to the problem.
Baghouse
System Upgrade
Client Titan
Description ETS was retained
by a leading cement manufacturer to improve the performance of a large
clinker cooler baghouse system. The operation was plagued with high emission
rates and premature fabric failure. ETS was able to identify the causes
and recommended a list of solutions, including modification of bag construction
and baghouse system components. ETS was given the contract to engineer
and supervise the implementation of these modifications. The end result
is that the system is operating reliably with no emission problem, and
bag life has been increased from less than one to more than three years.
The client was so pleased with ETS's work, they contracted
ETS to upgrade their finish mill and row mill baghouses. ETS has also performed
numerous diagnostic and compliance tests along with trial burn emission
tests for this client over the last 20 years.
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