May 1-5, 2011
One of the measures of the prosperity of a nation is per capita consumption of electricity. In developing countries like India the gap between supply and demand is strongly increasing. The demand for all forms of energy is expected to increase substantially in the foreseeable future and is forecasted to double by 2020. Although coal would continue to be a major energy source in India due to its availability, lignite is fast emerging as an alternate source of fuel for electricity generation. In India the total lignite potential is 4177 million tonnes. The varieties found in India (Gujarat & Rajasthan region) have moderate to high sulphur (1 to 15 %wt dry ash free) content. It has become economically necessary to use this lignite for power generation in view of spurt in energy demand while caring for the environment (by controlling the SO2 emission). CFB boilers with their in-furnace SO2 capturing capability perfectly suit these demands and are very attractive while their utilization in comparison with pulverized fuel boilers would require very expensive add-on flue gas conditioning systems. The CFB boiler technology designed by BHEL (see Notation list for acronyms) has been successfully demonstrated for utilities at the 2x125 MWe power project at Surat. Based on the excellent performance of the units at SLPP, BHEL has bagged order for 2x125 MWe CFB power plant for RVUNL at Giral, Rajasthan and 1x75 MWe CFB power plant for GEB, at Kutch, Gujarat. The plant at Giral is now operating after overcoming unique challenges for firing >15%daf sulphur lignite (one of highest sulphur-content fuel used in CFB utility-scale units). This paper provides an overview of the CFB process, its advantages, the development of CFB technology, and the experience gained from these units in particular attention to lignite fired units of 125 MWe capacities. The teething problems experienced during initial operation and their resolution form part of this paper. With the experience gained at Giral, firing high-sulphur lignite, BHEL is uniquely placed among CFB boiler manufacturers to meet market requirement of using such demanding fuels for power generation. The successful operation of the boiler after surmounting the issues is bound to stimulate utility users to adopt CFB technology for their proposed projects for such challenging fuels also. Many other large capacity BHEL CFB boilers (firing range of fuel: from Indonesian coal, lignite with high/medium sulphur to petroleum coke) are under various stages of commissioning and will be in operation in another few months.
M. Lakshminarasimhan, B. Ravikumar, A. Lawrence, and M. Muthukrishnan, "High Sulfur Lignite Fired Large CFB Boilers-Design and Operating Experience" in "10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10", T. Knowlton, PSRI Eds, ECI Symposium Series, (2013). http://dc.engconfintl.org/cfb10/65