Preliminary Performance Results on Retrofitting Gas Cofiring on a Coal Stoker Boiler

The realities of boiler operation at the end of the 20th Century require that the boiler run as clean as possible. No more are we allowed startup opacity spikes, no more soot blowing opacity spikes, NOx and S02 can be sold as commodities on the open market and downwind states require upwind operators to clean up their smog. We all breathe the same air and it seems like there is less and less. Forward looking boiler operators are looking for solutions to these problems at the lowest cost. Up to now, stoker boilers have been grandfathered and have been allowed to operate within certain limits. The application of continuous opacity monitors has sharpened the dialogue with state regulators to look for solutions. One of these solutions is the installation of a small gas burner in the upper furnace. This burner can be used for boiler warmup, cold start up or shut down; but it can also be used to reduce NOx, S02 and particulates. This paper presents actual results from a single burner installed in the upper furnace of a 70,000 LB/hr stoker boiler. The results are a preliminary snapshot without any tuning or optimization of the process.