Jan. 2023 - Periodic Monitoring can Prevent Forced Outages During Peak Demand

Storm Technologies, Inc. has long been an advocate for performance-driven maintenance programs. By conducting routine performance testing on the coal pulverizers and boilers, small problems can be identified and often addressed before they potentially cause the unit to be derated or even worse, forced into an unplanned outage. These unplanned forced outages often come during peak power demand periods when the price per MW is high and desired for the boiler to be operated at maximum capacity with a “hands-off” operating policy.

• Air In-Leakage
• Corrected Gas Outlet Temperature
• X-Ratio
• Gas Side Efficiency
• Pressure Drop

Most boilers are equipped with tube metal thermocouples installed on the terminal superheater and reheater tubes and provide an indication of the final metal temperatures of the selected tubes. This is important because metals, just like most other materials when heated, have properties that begin to change and, therefore, knowing your metal’s limitations is important.  This newsletter will address the common questions of:

1. How hot is too hot for your tubes?
2. What kind of reduction in tube life can be expected if the tubes are operated above design temperatures?
3. How can we prevent elevated tube metal temperatures?

This is a follow-up to our June Newsletter which focused on combustion airflow measurement and balance. Fuel Balance and fineness are also important for optimum combustion, best heat rate, fuel flexibility, minimal slagging, best NOx performance and more. If one were to take a look at Storm’s 13 Essentials for achieving optimum combustion in pulverized coal boilers, 9 of the 13  essentials are fuel related. We hope that you appreciate it and find it useful.

Storm Technologies has been solving difficult combustion problems for many years. We thought that sharing some of our experiences and case studies would be helpful to those of you working in the utility industry. Some of these same issues that we have identified and made corrections to are certain to still be challenges today. This is the first newsletter of a series that uses data and experiences from the last three decades. Most of the figures used are slides from our “Large Utility Boiler Combustion and Performance Improvements” seminar. We hope that you appreciate it and find it useful.

In our last newsletter, pt. 1 explored the limitations in emissions and obstacles in furnace performance in extremely low load operations. This time, we look at low load impacts on the pulverizers and the solid fuel injection system. This covers primary air flow and velocities and potential damage to out of service burners and their components...