Due to changes in design and operating parameters aimed at reducing NOx formation, cyclone-fired plants have had increased system challenges related to slag-flow behavior, including freezing of slag, water-wall slagging, convective-pass fouling, and fine-particulate formation. To address these challenges, MTI has just launched a multi-client project to develop improved tools to manage lignite properties and plant operations based on measureable lignite properties. These tools can be used to improve low-NOx cyclone operation.
MTI has extensive experience developing tools to address slag-flow challenges in combustion systems. These tools have been aimed at improving combustion system (pulverized and cyclone fired) performance, managing ash deposition, and controlling particulate-matter emissions. Our clients have used these tools in fuel planning and blending.
Further improvement of these tools is needed as a result of changes in cyclone design and operation. To reduce NOx formation, cyclones are now operated at substoichiometric combustion conditions with air added to upper regions of the furnace to complete combustion. The new tools developed by this project will take into account the new modifications in cyclone-fired system design and operating parameters.
To achieve the project’s goal to develop new tools to manage lignite properties and plant operations toward improved low-NOx cyclone operation, MTI has identified the following objectives: 1) Review past and current strategies to optimize system performance, 2) Review properties of coal being delivered to the plant (current and future), 3) Determine impacts of combustion control of NOx on slag and ash behavior, 4) Improve existing tools and develop new tools for plant operations and mining personnel to utilize, and 5) Test and validate tools through testing at the plant.
In addition to providing updated tools to facilitate optimum slag-flow management with low-NOx cyclone operation, MTI will also provide plant personnel training sessions on lignite properties, slag-flow behavior, slagging/fouling, and particulate control associated with cyclone-fired systems.
Finally, this project is of value to the state of North Dakota. A major challenge facing North Dakota lignite-fired utilities is managing highly variable lignite properties. This project will develop data and tools to identify cost-effective measures to decrease NOx emissions, slag freezing, ash deposition, and particulate collection and handling problems as a function of system operation conditions and lignite blends.
Funding for this project is from a Lignite Research Fund (administered through a partnership between the Lignite Energy Council and the North Dakota Industrial Commission), Minnkota Power Cooperative, BNI Coal Ltd, and Clean Coal Solutions.
For more information, please contact us at 701-777-6530.