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Levendis Awarded $240K NSF Grant

MIE Professor Yiannis Levendis was awarded a $240K NSF grant to determine the "Combustion characteristics of pulverized torrefied biomass for use in co-firing boilers".


Abstract Source: NSF

To satisfy energy needs of the fast-growing global population and minimize the negative impact on the environment, alternative energy sources are needed. The U.S. has a large capacity for renewable biomass production, the utilization of which can reduce the total carbon emissions. Partial substitution of coal with biomass can be a viable option for generating the baseload power that most alternative sources (wind, solar, tidal) cannot supply due to their intermittent nature. However, biomass is moist, biodegradable and fibrous. Thus, it is costly to transport, store and grind for use in the boilers. This research will address the combustion of torrefied biomass, which has been subjected to the process of torrefaction (akin to coffee roasting) to remove moisture, chlorine and sulfur. However, as grinding costs drastically increase with decreasing targeted grind size, this work aims to identify appropriate maximum torrefied biomass particle size ranges for effective combustion in existing boilers. Such knowledge is needed for torrefied biomass to become a standardized product for burning in virtually unmodified coal-fired plants. During the course of this research, students will be educated in the energy field and several international collaborations will be advanced on the subject of harvesting bioenergy to help achieve a sustainable environment.

This research will generate new knowledge pertinent to effective combustion of torrefied biomass in utility boilers. This investigation will identify methods for assessing the proper size of various kinds of torrefied biomass materials (including several typical woody and herbaceous biomass types) for co-firing with pulverized coal, while maintaining high combustion efficiencies and high radiative fluxes in existing boilers. Data pertinent to particle burnout times, temperatures of both volatile matter flames and residual chars, in-flame soot volume fractions, particle-to-particle interactions, carbon burnout are needed to predict reaction rates, heat fluxes, and slagging and fouling deposition tendencies in boilers. The proposed fundamental research will assess these combustion parameters of pulverized torrefied biomass at the particle level, by monitoring entire combustion histories of single particles pyrometrically and cinematographically. These will be compared to analogous data for coal particles of all ranks, previously collected in this laboratory. Subsequently, combustion effectiveness and particle-to-particle interactions will be assessed by burning streams of neat and blended fuels and emissions will be monitored.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Related Departments:Mechanical & Industrial Engineering