Experimental Investigation of Combustion Characteristics and Emissions for a Pilot-Scale Bubbling Fluidized Bed Combustor Fueled by Biomass Chips of Sesame and Broad Bean Stalks

ABSTRACT

The study work investigated the combustion characteristics and gaseous emissions during burning chips of sesame and broad bean stalks in a pilot-scale Bubbling Fluidized Bed Combustor (BFBC). The effects of the startup temperature, excess air percentage, moisture content, and injection location of secondary air on axial temperature profiles along the combustor and flue gas emissions were studied. The results indicated that biomass fuel characteristics have a significant role in the distribution of axial temperature along the reactor height. A great effect on the axial temperature profile was detected when the startup temperature was changed. The 30% and 100% excess air represent the near percentages for better combustion characteristics for burning the stalks of broad bean and sesame, respectively. Enhancement was observed in the combustion behavior when using the dried samples compared to the as-received samples. Higher values of axial temperature and lower concentrations of flue gas emissions are a result of rising injection location of the secondary air. The combustion efficiency reached to 92.4% for burning the sesame stalks and 96.6% for the broad bean stalks. Based on an energy balance performed on the BFBC, the thermal efficiency was ranged from 28.2% to 59.4% for SS and from 17.2% to 42.1% for broad bean stalks.

KEYWORDS:

• Sesame stalks
• broad bean stalks
• biomass chips
• bubbling fluidized bed combustion
• combustion characteristics
• emissions