Effect of Coconut Shell Moisturizing on Combustion in Conical Swirling Fluidized Bed Combustor

บทคัดย่อ

 This work aimed to study the effects of fuel moisture on firing in conical swirling fluidized bed combustor by using shredded coconut shell as a fuel. Annular spiral distributor at 14 degree to horizontal axis was used to generate the swirled motion inside the combustor. The fuel was moisturized by spraying water to acquire fuel moisture content from 10-35%. Sand particle size of 600–850 μm was used as the inert bed material with 20 cm bed height. The fuel feed rate was fixed at 45 kg h-1, for variable excess air (of 40–100%). The axial temperature profile in free board region were found to be rather uniform and independent of excess air but noticeably affected by the fuel moisture. CO and NO concentrations reduced drastically along the combustor height in all the test run affected by the injection of secondary air from the burner. Therefore, CO and NO emissions were at a quite low level. As revealed by experimental results, through moisturizing as–received coconut shell, NO emission could be reduced, however, CO emission increased, its depend on the excess air. CO emission were found about 100-350 ppm and 50-230 ppm for NO emission. Firing shredded coconut shell at the above fuel moistures could be achieved 88-99% combustion efficiency.