Energy saving and emission reduction opportunities in mixed-fueled industrial boilers

In this article, an “energy efficiency” study has been performed in an industrial establishment. The boiler of this industrial establishment is a mixed‐fueled (solid + gas) type and operated with different fuels as coal, coke gas, and blast furnace gas, the pressure of 7000 kPa (70 bars) and temperature of 778.15 K (505°C) and with a nominal capacity of 27.77 kg/s (100.000 kg/h) steam. In this context, the working temperature, pressure, velocity, and combustion gas measurements have been carried out at the boiler operation conditions. Using with all these measurements, the energy and mass balance equations have been set and the boiler efficiency has been calculated as the value of 85.91%. The main efficiency losses have been determined as: operating the boiler at the high air excessiveness coefficient, the air leakage in the rotary type air heaters and the heat losses of the surface. Total energy savings potential is 2,029,692 kcal/h. When anticipated enhancements can be carried out, the boiler efficiency will be 88.94%. In this case, 4861.7 tons of carbon dioxide emissions per year will be reduced. © 2014 American Institute of Chemical Engineers Environ Prog, 33: 1350–1356, 2014