Boiler performance and cost analysis of fuels and fuel blends using the Fuel Quality Advisor

• Spreadsheet-based advisor developed to estimate fuel quality impacts on boilers
• Utilizes common fuel analyses and boiler information to estimate performance, compared to baseline fuel, in the following areas:
• Slagging
• Fouling
• T250 temperature (Viscosity)
• Corrosion
• Erosion
• Abrasion
• NOx emissions
• Load limitations
• Mercury compliance
• Several examples are presented from various units and boilers of the results from over 100 estimations
• The Advisor correctly estimates changes in fuel quality impacts relative to a baseline fuel

Fuel quality is one of the most critical variables in determining the heat rate, efficiency, and performance of power plants. The drive to leverage fuel switching and/or blending to meet more stringent SO2 and NOx emission requirements has, in many cases, led to both a reduction in power station efficiency and a poorer net plant heat rate (NPHR). In addition, fuel switching and/or blending can lead to a significant reduction in operating margins and increase the risk of unit derates. To maintain boiler efficiency and performance, there is a strong incentive to manage or mitigate this risk. A first step in evaluating fuel options is using the spreadsheet-based Fuel Quality Advisor. The Advisor incorporates fuel quality information, furnace operating conditions, as well as some basic furnace design information to estimate the maximum boiler load potential, fuel cost/MWh, deposition tendency, mercury compliance, ash resistivity, corrosion potential, and backpass erosion potential.The basics of the Fuel Quality Advisor have been presented earlier; this paper presents results from a major US utility who used the Advisor to evaluate over 70 fuels and fuel blends for 10 of their larger coal-fired boilers. Combining the estimated performance from the Fuel Quality Advisor with actual operating experience using the new fuels or fuel blends has permitted the Advisor to be tailored to each specific unit — thus increasing the reliability of the estimations. This paper discusses the use of the Fuel Quality Advisor by the utility as well as several of the resulting estimations and comparisons to actual operations.