Benefits of performance monitoring:
- Regular feedback on catalyst activity and conversions
- Performance analysis for each layer
- Analysis of deactivation mechanisms
- Prediction of future behavior of each layer
- Guidance for catalyst replacement
Product Surveillance provides valuable information about the SCR DeNOx catalyst and system during operation to predict catalyst lifetime and to remain in compliance with clean air regulations.
In order to estimate catalyst lifetime and appropriate catalyst replacement intervals to ensure that clean air regulations are met over the operating lifetime, the performance of the DeNOx system should be monitored. Johnson Matthey offers as part of the Product Surveillance Program full support for the SCR catalyst and system: reactor inspection and catalyst sampling, catalyst evaluation and catalyst management and replacement strategies.
SCR catalyst performance monitoring
To assess the condition of the catalyst during its operation, it is important to monitor the overall DeNOx SCR catalyst system performance (e.g., temperature, NOx conversion, NH3 slip). It is especially useful to remove catalyst samples at regular intervals for performance and analytical evaluation. Johnson Matthey can design a customized test plan for each application which specifies catalyst sampling intervals and appropriate test conditions. Test results can often identify potential causes of catalyst deactivation such as sintering, plugging with ammonium bisulfites or ash, and poisoning. This allows correction of potential problems to minimize future deactivation. Regular screening creates a history of catalyst performance which allows the design of the best catalyst management strategy.
Long-term catalyst management - max NOx reduction
and min NH3 slip correspond to catalyst replacement
SCR catalyst management strategy
The catalyst management plan is based on experience with each application. Once a history of catalyst performance is established by regular monitoring of the overall system performance and evaluation of each catalyst layer, Johnson Matthey can recommend the optimum catalyst replacement schedule.
SCR maintenance contracts
Upon SCR system delivery, customers can choose a maintenance contract with different levels of service to meet their specific needs. A basic contract includes two visits per year. During these visits SCR systems are inspected and preventive maintenance is performed. Other contracts, typically for large SCR systems, may also include catalyst monitoring. Catalysts are inspected according to a defined interval depending on operating hours, fuel type, etc. Some catalyst blocks may be removed for analysis in our laboratories and based on the results, life-time predictions can be given.
We also offer comprehensive Full Service Contracts that cover preventive maintenance, corrective maintenance and catalyst monitoring, cleaning and replacement. If you are interested in a service contract for your existing or new SCR system, contact us for information or for a contract proposal.
Johnson Matthey's technology centers have world-class capability for catalyst evaluation. We can evaluate the activity of a catalyst by exposing the catalyst to simulated exhaust conditions while measuring catalyst performance. This can also be done under accelerated aging conditions. Complete forensic evaluation of the catalyst can be done using highly sensitive X-ray techniques, surface area and pore structure analysis and microscopy to identify effects of over-temperature, masking or poisoning. Product surveillance will ensure that the plant is always in compliance with all clean air regulations. In addition, the catalyst management plan lays the groundwork for technical and commercial planning.