At CSU Drake Station With Targeted In-Furnace Injection™ Technology
Excerpt from technical paper presented at ASME Power 2010 – Chicago, IL
James Towell, Tom Martinez, David Hightower, Richard Maxey – Colorado Springs Utilities
Gerry Snow, PE; Hector Gonzalez; Robert Rians – Fuel Tech, Inc. Warrenville, IL
Power generating stations are under continuous pressure to achieve maximum availability, high efficiency, and minimum environmental emissions at the lowest possible cost. In recent years, increased fuel flexibility has become more critical, financially and operationally, than ever before. Colorado Springs Utilities (CSU) has been very progressive in adopting and implementing benchmark technologies and operating strategies to help achieve these goals across their diversified generation portfolio, and in particular at four operating coal units representing 462 megawatts in the system. One key strategy employed at CSU’s Martin Drake Station has been to continuously evaluate and test alternative coal feedstocks which have potential to reduce cost while maintaining capacity, fuel supply security, availability, and efficiency. These tests were made possible by the use of Fuel Tech’s Targeted In-Furnace Injection™ (TIFI®) technology to control slagging1 and fouling, reduce forced outages and load drops, and enhance unit efficiency. The TIFI process uses Computational Fluid Dynamic (CFD) modeling to predict the precise trajectory of an injected chemical, helping to ensure as close to 100% coverage of the targeted zones as possible.
With TIFI installed on Units 6 and 7 at Martin Drake Station, the operators were able to blend Powder River Basin coal with design fuel up to double the percentages previously achievable. Using TIFI, the plant was able to maintain full load generation, better control slagging deposits, show improvements in heat absorption, and reduce attemperator spray flows over previous blend trials. Including the cost of the TIFI program, the station has demonstrated a potential annual operating cost reduction approaching $4.9 million. Effective return on TIFI program investment is 4:1.
The Martin Drake Power Plant comprises Units 5, 6, and 7. Units 5 and 6 are wall-fired boilers rated at 46 MW and 77 MW, respectively. Drake Unit 7 is a 1,336 MMBtu/hr (nameplate) Babcock & Wilcox wall-fired, dry bottom, coal-fueled boiler rated at 131 MW (net). Unit 7 entered commercial operation on June 14, 1974 and a reverse-air fabric filter baghouse was placed in service on Drake Unit 7 in November 1993. Low NOx burners were installed in October 1999.