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NOxAssure The first initiative under this strategy was to prove the commercial viability of catalyst
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SCR-Tech uses only certified testing laboratories operated under VGB regulations (VGB Guideline for the Testing of DeNOx Catalyst (VGB-R302He), the international standard for catalyst testing. We measure under actual field conditions with full-size catalyst plates or elements. The lab personnel are some of the front runners in the development of the cleaning and/or regeneration process. VGB, the equivalent of America’s EPRI, developed these testing guidelines in cooperation with utilities, catalyst manufacturers, equipment manufacturers, and European testing institutes. For this testing we prefer laboratories that have the capability to test full length elements and include prototypical humidity in the test gases. This prevents two sources of error that can result from using corrections for both length and humidity when actual values are excluded. In addition, U.S. laboratories also have developed the capability of including high prototypical concentrations of sulfur dioxide in the test gases to mimic those produced in the U.S. through the use of high sulfur coals. Europeans, who generally do not fire such high sulfur coals, may not have this capability. Reports from these certified catalyst testing and chemical analysis labs are consistent in their content and layout for ease of comparison between operations of various SCR systems and catalyst types. Testing information is compared to our extensive database and interpreted based on long-term SCR operating experience with different fuel types. The combined results of this effort are used to monitor and forecast SCR system and catalyst performance and to accurately forecast the development of the installed DeNOx potential. By comparing the forecast with the required minimum DeNOx potential, the point in time for the need for catalyst regeneration or replacement can be identified allowing for the necessary outage planning well in advance of the actual occurrence. |
As part of our SCR management program, SCR-Tech provides ammonia injection grid (AIG) tuning services to optimize the operation of the AIG and reduce O&M costs. A team of experienced technicians and engineers will test the unit’s AIG under actual operating conditions and then, using the fixed installed sampling grid after the last catalyst layer, a series of tests will be conducted for tuning the AIG until it is operating at peak performance. We recommend an optimization of the flue gas distribution and tuning of the ammonia injection grid (AIG) at least once a year and prior to the start of each ozone season utilizing a MAFGAS (mobile automated flue gas analysis system) which is used to measure the NO and O2 distributions after the last catalyst layer The MAFGAS system is used for fine tuning the ammonia injection grid, the investigation of load dependent NO operating points and possibly the determination of the NOx reduction efficiency of a single catalyst layer. Providing quasi-simultaneous flue gas analysis over the SCR’s entire cross-sectional area by operating up to six (6) NO/O2 analyzers in parallel, the MAFGAS accurately determines the NO and O2 concentrations in the flue gas at up to 100 measuring points within thirty (30) minutes using the fixed sampling grid installed after the last catalyst layer. The results are directly converted online into a three dimensional concentration profile in order to allow a correct evaluation of the found distribution, which then can be optimized. Mobile Automated Flue Gas Analysis System (MAFGAS)
Minute monitoring of NH3 slip through NH3 in the fly ash is essential for tracking the SCR system performance and the catalyst deactivation. operating hours |
SCR-Tech maintains a stock of regenerated catalyst to provide emergency or spare layers of catalyst for our customers. We currently have an inventory of more than 1,000 m3 of catalyst available for sale. Providing regenerated catalyst offers power plant operators a new, more cost-effective alternative to purchasing new catalyst for the initial fill of empty layers. As demand increases, this inventory is expected to grow. Stock of Regenerated Catalyst at SCR-Tech’s Warehouse in Charlotte, NC StorageIt is essential that catalyst be stored in a catalyst-friendly dry environment that will prevent deterioration, further deactivation, or the solidification of fly ash and popcorn ash into a hard conglomerate on the catalyst surface. We have approximately 33,700 square feet of storage space capable of housing more than 1,000 catalyst modules. Our storage facility is a steel and concrete structure located adjacent to our regeneration plant and consists of a receiving office, final inspection station, and packaging / shipping areas. Additional storage space is available in another on-site building, and off-site storage can be made available as well. ShippingCatalyst requires special handling during shipment. SCR-Tech has the experience to advise our clients on the correct way to package, load and unload catalyst module for shipping and in particular the correct manner in which the modules need to be positioned on the truck to prevent damage during shipment. SCR-Tech’s facility includes loading docks and bays which can accommodate 15 trailer trucks.
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SCR-Tech uses the services of certified labs for catalyst testing and analysis to determine catalyst deactivation causes and provide information for system optimization and determining the best catalyst regeneration process required for each client. Testing includes:
Bench-scale reactor in EnBW’s catalyst testing laboratory All testing is done in strict accordance with the internationally accepted German |
SCR-Tech recommends that the SCR reactor be inspected at least once a year. A visual inspection provides valuable information on the operation of the SCR reactor and the reasons for actual or potential problems.
Regular catalyst inspection and sampling can pinpoint potential problems, provide information on deactivation causes and their prevention, and also extend the life expectancy of the installed catalyst. We recommended that catalyst samples be taken from the reactor at least once a year and whenever there is access to the reactor. The more data points that can be generated from catalyst testing, the easier it will be to determine the catalyst’s deactivation cause and rate. This information is essential in planning a cleaning, rejuvenation, regeneration, or catalyst replacement strategy well in advance of the next scheduled outage.
Plugged honeycomb catalyst Plugged plate catalyst
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Minimizing overall costs for a single SCR system or for large fleets requires an intimate knowledge of catalyst, its replacement, rejuvenation and regeneration cycles, and how a plant’s upstream and downstream equipment and fuels fired can play a factor in its performance. Effective catalyst management often means cutting ties with a “one size fits all” approach. The best and / or most cost-effective solution often results from flexibility in catalyst selection, methods of replenishment, and an informed management approach. SCR-Tech develops catalyst management plans for its customers consistent with catalyst activity decay, ammonia slip and scheduled outages, with the understanding that some plants make a market in ash. SCR-Tech’s comprehensive catalyst management programs include performing inspections, AIG tuning, computer simulation and tracking of catalyst decay rates, evaluating the effects of fuels fired, providing catalyst test programs and guidance on catalyst interchangeability between units with options for new, brokered, rejuvenated and regenerated catalyst for either a single unit, a plant site, or the entire fleet. As part of its catalyst management program, SCR-Tech offers a customized catalyst regeneration plan scheduled around planned outages.
The Perpetual Cycle of SCR Catalyst Management There are a considerable number of options for optimal catalyst management: add a layer; replace a depleted layer with new or regenerated catalyst; or mix and match plate, corrugated, or honeycomb catalyst in the same reactor. All of these options will change with year-round SCR operation. No matter which catalyst type is being used, there are many possibilities for minimizing costs associated with a fleet of SCR systems. Other considerations include trying to match the use of catalyst to scheduled outages – the intervals between which will only get longer with the onset of year-round SCR operation. This alone may mean planning for catalyst replacement or replenishment in multiple layers. There are also possibilities for managing or avoiding catastrophic catalyst failure. Pooling spare catalyst within the fleet and even within the industry at a central location can provide a safe margin for avoiding long, unplanned, and economically devastating outages. This strategy can be accomplished without a significant investment. SCR-Tech has developed many programs that can evaluate nearly any catalyst management scenario. These programs can predict catalyst life, allow for the mixing and matching of different catalyst types, handle multiple fleet SCR systems, and evaluate site-specific economics associated with each scenario. They also provide risk assessment associated with extending catalyst life, based on previous experience. These assessments are always backed by independently verified third-party catalyst testing. SCR-Tech Catalyst Management Benefits
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Proven SCR Catalyst and Management Services Now Available in North America The most effective way to operate an SCR system is via a comprehensive catalyst management program. Catalyst management is often viewed as developing a plan for a given SCR system to maintain sufficient catalyst activity necessary to achieve the required NOx reduction with an acceptable margin to avoid inadvertent NOx or ammonia slip excursions beyond allowable limits. SCR-Tech provides a broad array of customized SCR and catalyst management services, including guidance on effective SCR and catalyst management strategies, with the objective of assisting plant operators in optimizing the operation and performance of their SCR systems while reducing their O&M costs and achieving cost-effective NOx compliance. These services include:
Custom-tailored Service Plans Augmented by Custom-tailored ServicesSCR-Tech provides SCR management services for individual plants, on a multi-plant basis, or under a fleet-wide blanket agreement. All SCR management services are offered “a la carte,” ensuring a pre-stated price for each specific service portion, while allowing the flexibility to select and combine portions on an as-needed basis, tailored to the individual SCR system. This approach augments the advantages of a clearly defined scope of services delivered at a firm lump-sum price, with the ability to pick and choose only the service portions required at any specific point in time, for an individual SCR unit. Data-driven planning and scenario analysis facilitate:
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SCR performance tracking is based on the catalyst data generated in certified labs and is part of the perpetual cycle of SCR management. It provides an overall view of the efficiency of the SCR reactor as well as the activity level of each layer of catalyst.
The above chart illustrates the potential as well as actual activity level of a reactor and its individual catalyst layers. The above referenced plant was originally designed to use plate catalyst but currently uses both plate and honeycomb catalyst from different manufacturers. |
SCR-Tech has developed a “Wrap” program to offer its customers the option of leasing SCR catalyst purchased and owned by SCR-Tech. For one plant or an entire fleet, the lease option provides customers with a complete catalyst management program including:
Benefits to customers include:
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