Browsing by Subject "combustion"

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    On the existence of traveling waves in the 3d Boussinesq system
    (2008-10-14) Lewicka, Marta; Mucha, Piotr B.
    We extend an earlier work on traveling waves in premixed ames in a gravitationally stratified medium, subject to the Boussinesq approximation. For three-dimensional channels not aligned with the gravity direction, and under the Dirichlet boundary conditions in the fluid velocity, it is shown that a non-planar traveling wave, corresponding to a non-zero reaction, exists, under an explicit condition relating the geometry of the crossection of the channel to the magnitude of the Prandtl and Rayleigh numbers, or when the advection term in the flow equations is neglected.
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    Production of Energy and Chemicals by Thermochemical Conversion from Recycled and Renewable Biomass
    (2016-08) Zhu, Cheng
    Recovery energy from municipal solid waste and biomass are one of the leading methods to achieve maximum energy efficiency and environmental sustainability. My research mainly includes two projects, novel biomass-supported sorbent for coal combustion emission control and fundamental study of biomass fast pyrolysis in the presence of alkaline earth metals. The first research project was collaborated with Accordant Energy LLC. on the development of ReEngineered Feedstock (ReEF), consisting of sorbent containing post-recycled paper and plastics. ReEF was evaluated in a laboratory-scale fluidized bed combustor system. The results indicate that co-firing ReEF with coal provides SO2 reduction in flue gas up to 85% as well as higher carbon conversion than pure coal combustion. Sulfation kinetics of ReEF combustion were evaluated in a drop-tube reactor. Sulfation of calcium hydroxide in ReEF was delayed due to RDF combustion when compared with pure calcium hydroxide sorbent. The second project investigated the catalytic effect of alkaline earth metals on cellulose pyrolysis primary (transport-free) and secondary (diffusion-limited) reaction pathways. Catalytic materials included homogeneous metal ions from their inorganic salts, and their corresponding heterogeneous metal oxides. While oxides were shown to have limited impact on cellulose pyrolysis chemistry, metal ions were found to significantly alter the secondary reaction pathways of cellulose under diffusion-limited conditions. The initial breakdown kinetics of cellulose were examined using a millisecond, thin-film reactor called PHASR (Pulse-Heated Analysis of Solid Reactions). Using the cellulose surrogate, α-cyclodextrin, the energetics of cyclodextrin decomposition were characterized. An interesting finding is that cellulose undergoes two distinct kinetic regimes with a distinct transition at 467 °C, which is interpreted as a reactive melting point.