Experience with Combining PRB and Eastern Bituminous Coals on two 511MW Boilers with an Advanced Low NO_X Combustion System

摘要

Kentucky Utilities Company purchased new low NO_X burners and an overfire air system for Ghent Generating Station Units 3&4 in 1998 and 1999 respectively. The turnkey projects were awarded to Advanced Burner Technologies Corp. The boilers had been firing low sulfur Kentucky bituminous coal and the new combustion system was designed for that coal range. In between the two ABT combustion modifications, the station began using a blend (in furnace) of PRB and bituminous coal. Plant data and NO_X emissions were recorded while burning various PRB/bituminous ratios. The effects on plant operating equipment and on the pre and post low NOx burner retrofitted boilers were observed. As a result of the effects of burning higher PRB/bituminous ratios, the plant now limits the PRB to a 50/50 blend. Using this in-furnace blend, NO_X is below 0.3 lb/MBtu with OFA ports closed.