Fabric and Fabric Filter Bag Testing Case Studies |
Testing Case Studies Steel Plant Electric Arc Furnace Electric Utility Reverse Air Baghouse Molecular Sieve Supplier Utility Plant in Southeastern United States East Coast Based Utility Union Chemical Division of Union Oil USEPA/IERL, Research Triangle Park, NC Lonestar Steel Co. Ironton Iron Baltimore Gas & Electric - Crane Station
Fabric Testing to Assist in Making Purchase Client Steel Plant Electric Arc Furnace Baghouse Purchasers of fabric filter baghouses and fabric filter bags who are aware of the BFP verification program have appreciated the credible and high-quality performance information that is generated by the program. ETS is the only laboratory approved for filtration product testing within the EPA ETV Program. To date there have been several reported cases where fabric filter operators have used the information gleaned from verification statements and their accompanying reports to assist them in their filter media purchasing decisions. A U.S. based steel producer was replacing the fabric filter bag set from a reverse-air baghouse serving its electric arc furnace. The baghouse contained more than 2,000 bags and was treating approximately 14,000 m3/min. (500,000 ft3/min.) of flue gas. The purchaser was deciding between either a non-membrane or membrane filter fabric. In this case the purchaser selected the membrane filter fabric because the verification test data indicated that the membrane offered lower operating pressure drop and minimized the potential for process upsets than would the non-membrane fabric. The lower pressure drop offered a savings of $20,000/cm w.g. ($50,000/in. w.g.). This savings resulted in a lower total cost of compliance for the membrane fabric, in spite of its higher purchase price when compared with the non-membrane fabric. Fabric Testing to Assist in Making Purchasing Decisions Client Electric Utility Reverse Air Baghouse Purchasers of fabric filter baghouses and fabric filter bags who are aware of the BFP verification program have appreciated the credible and high-quality performance information that is generated by the program. ETS is the only laboratory approved for filtration product testing within the EPA ETV Program. To date there have been several reported cases where fabric filter operators have used the information gleaned from verification statements and their accompanying reports to assist them in their filter media purchasing decisions. An electric utility used the ETV test data for guidance in replacing 9,000 fabric filter bags in its reverse-air baghouse. The baghouse contained over 9,000 bags treating 68,000 m3/min. (2,400,000 ft3/min.) of flue gas from a coal-fired boiler. The utility's procurement budget was well over $1,000,000. An evaluation of viable filter fabric candidates resulted in a short list of two filter fabrics. Both filter fabrics had membranes. The facility used the ETV data to identify differences in emissions and pressure drop performance between the competing membrane fabrics, and ultimately selected an ETV-verified media based on the verification data. A representative of the company supplying the selected membrane stated that "the verification test report demonstrated that membrane fabric is a viable means to lower pressure drop and that all generic membranes are not the same." Using Bag Filtration Products (BFP) Verification Testing to Accelerate Permit Process
Client Molecular Sieve Supplier Purchasers of fabric filter baghouses and fabric filter bags who are aware of the BFP verification program have appreciated the credible and high-quality performance information that is generated by the program. ETS is the only laboratory approved for filtration product testing within the EPA ETV Program. In addition to being a valuable marketing tool for vendors and informational resource for fabric filter operators making purchasing decisions, the BFP verification program provides federal, state, and local regulators with improved ability to make informed decisions. In providing access to credible and objective performance test data, the BFP verification statements provide the regulators with a demonstrated technology basis for streamlining the permitting process and compliance testing requirements. The California South Coast Air Quality Management District (SCAQMD) has recently adopted a rule (Rule 1156) that provides incentives for cement manufacturing facilities to use ETV-verified baghouse filter fabrics to control particulate emissions. By reducing the required compliance testing frequency from annual to every five years, this rule can provide significant cost savings to users of verified technologies (SCAQMD, 2005, Pham, 2006). Recognizing the importance of having a global standard for fabric filter media testing, the ASTM has adopted the ETV Baghouse Filtration Products testing protocol as the basis for its standard (ASTM D6830-02) promoting standardization and consistency in performance evaluation for these technologies. The International Standards Organization (ISO), a worldwide voluntary standards organization, has also proposed ETV testing protocol as their standard. A major supplier of molecular sieve adsorbents, with facilities in Europe and the United States, was in the process of revising the operating permit at its Louisville, Kentucky plant. The facility operates about 25 baghouses on a variety of process operations, including a number of high temperature (greater than 300° F) applications. In an effort to streamline the permitting process, the company requested that the Kentucky Department of Environmental Quality (KYDEQ) consider verification test data from the ETV program in lieu of compliance testing. The agency agreed to this request with the provision that additional tests be conducted using the ETV and ASTM test protocols. These additional tests were to be conducted using test dusts that were actual process dusts extracted from the applications identified in the revised permit application. Tests were conducted on three different dusts. Three fabrics supplied by BWF-America were tested; a 22-ounce polyester felt fabric with a singed collection side, a specialty aramid felt fabric crafted of micro-denier fibers and an enhanced scrim (the same construction as the BWF polyester material that was tested and verified by EPA/ETV in June, 2002), and a P84 felt fabric with a finish treatment for improved dust cake release. Testing was conducted in accordance with ASTM 6830-02 with test specifications and conditions as detailed in the Generic Verification Protocol (GVP) for Baghouse Filtration Products developed by the ETV Air Pollution Control Technology (APCT) Center, operated by RTI International under a cooperative agreement with the EPA's National Risk Management Research Laboratory. Because of time constraints and the limited quantity of test dust available, testing was limited to one test run per fabric/dust combination. The test results showed that outlet (exiting the tested filter fabric) emission levels were extremely low for both total mass particulates and PM 2.5 and were significantly below regulated levels set by the agency. These very favorable results were achieved for all filter fabric/dust combinations and were consistent with the results of the verification tests as reported in the June, 2002 Verification Statement for "BWF America's Grade 700 MPS Polyester Felt". The KYDEQ considered the ETV data along with the results of the additional filter fabric testing when reviewing the permit application. Furthermore, the agency accepted the data as a substitute for compliance tests and subsequently granted the revised permit. It is estimated that the acceptance of the ETV data (in lieu of compliance tests) significantly reduced the time and cost of the permitting process. Clint Scoble, president of BWF-America at the time, stated "the customer made the permitting process easier by running our materials through the ETV testing process". Develop Filter Fabric/Bag Quality Assurance Plan and Assist Client in Implementing the Plan
Client Utility Plant in Southeastern United States
The plan called for all fabric roll cases to be inspected to insure roll number, lot number, and certifications were in agreement. A sequential list of fabric roll numbers defining their order through the finish lot process was developed and roll numbers to be sampled identified. The group of fabric rolls for the subject fabric filter bag set were tagged and separated from other stock. Three levels of fabric testing were performed, with the highest percentage of stock being tested in Level III. In all there were 18 different parameters tested. Sewing thread was inspected for organic content (Loss on Ignition), breaking strength, ply quantity, and yarn designation.
After the lots were approved, filter bag fabrication was initiated. The plan called for two bags from each lot of 100 fabric filter bags to be tested for compliance to the ETS bag drawing and for the following specifications: length and width of filter bag, filter bag to cage fit, filter bag to tubesheet fit, and defects in the workmanship of the filter bag or fabric. The plan stated that if either of the two fabric filter bags out of a lot of 100 bags failed any inspection criteria, additional fabric filter bags from the same lot of 100 would be inspected for that failure mode. If additional filter fabric or filter bag failures were found, 100% of the lot of 100 filter bags would be inspected. All rejects were to be either repaired or discarded. Specifications were also included for the packaging, handling, and storage of the fabric filter bags that passed the acceptance criteria. The client embraced the plan, presented it to the fabric filter bag supplier and arranged for ETS to commence QA testing. For more information about ETS' QA/QC programs click here. Develop Filter Fabric/Bag Quality Assurance (QA) Plan, Conduct (QA) Testing, and Develop and Implement Long Term Bag Monitoring Program Client East Coast Based Utility The plan called for all fabric roll cases to be inspected to insure roll number, lot number, and certifications were in agreement. A sequential list of roll numbers defining their order through the finish lot process was developed and roll numbers to be sampled identified. The group of fabric rolls for the subject filter bag set were tagged and separated from other stock. Three levels of fabric testing were to be performed, with the highest percentage of stock being tested in Level III. In all there were 18 different parameters tested. After the fabric lots were approved, bag fabrication was initiated. The plan called for two filter bags from each lot of 100 bags to be tested for compliance to the ETS bag drawing and for the following specifications: length and width of filter bag, length under tension, anti-collapse ring alignment and spacing, orientation of cap to bag seam, and defects in the workmanship or fabric. The plan stated that if either of the two fabric filter bags out of a lot of 100 bags failed any inspection criteria, additional bags from that same lot of 100 would be inspected for that failure mode. If additional failures were found, 100% of the lot of 100 would be inspected. All rejects were to be either repaired or discarded. Specifications were also included for the packaging, handling, and storage of the fabric filter bags that passed the acceptance criteria. The bag monitoring program was conceived to determine the strength and flow characteristics of the bag set with on-stream (in service) time. As baghouse availability is always an issue in power generation, the reliability of the bag set was a major concern of the client. It was thought that this program would provide input in determining the useful life of the fabric filter bags, thus enabling the facility to conduct future bag set replacements during scheduled outages of the generating unit. The program called for representative filter bags to be removed from the baghouses every six months and sent to ETS for comparative testing with the new bag specifications. Typically a new fabric filter bag set will show a marked decrease in tested performance levels after the first few months of service time, after which the results level out and remain well above the failure plateau for a long period of time before experiencing another significant decline that approaches a level that would jeopardize the integrity of the bag set. The QA program was first instituted in 1986 and the fabric filter bag sets were installed in 1987. The filter bag monitoring program was instituted shortly thereafter and continued until it was determined that the bags had reached the end of their usefulness in 2000 and replacement was called for. The replacement fabric filter bags were subjected to the same rigorous QA program, and since their installation have continued to be monitored by ETS. Both the QA and bag monitoring programs have been considered successes by the client in that he was insured of receiving a high quality product that exceeded his bag life expectations, the filter bag monitoring testing determined when replacement was needed and the facility was able to schedule the change-out in a manner that didn’t impact on their ability to produce electricity. For more information about ETS' QA/QC programs click here. Improvement of Baghouse Performance Client Union Chemical Division of Union Oil Full-Scale Demonstration of a High-Velocity Fabric Filter System Used to Control Fly Ash Client USEPA/IERL BPMES Installation Client Lonestar Steel Co. Pilot Evaluation of an Iron Foundry Client Ironton Iron (Intermet Foundries, Inc.) A four-week pilot evaluation was conducted using a dry-injection feeder and baghouse treating a similar emission stream. The BPMES was used to monitor, collect, and organize baghouse performance data. Commercially available bag precoat material and powdered-activated carbon were injected over a range of feed rates. Although both types of injected material resolved the condensation problem with the baghouse, the use of carbon completely eliminated the visible emissions. Foundry personnel continue to use the lower-cost precoat material to solve the condensation problem while saving more than $100,000 per year in maintenance costs. The regulatory agency is reviewing the need to require carbon-injection for further control of the organics. BPMES Custom Modification Client Baltimore Gas & Electric - Crane Station
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