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Biomass is one of the important renewable energy sources. Biomass fuels exhibit a range of chemical and physical properties, particularly size and shape. Investigations of the behavior of a single biomass particle are fundamental to all practical applications, including both packed and fluidized-bed combustion, as well as suspended and pulverized fuel (pf) combustion. In this paper, both experimental and mathematical modeling approaches are employed to study the combustion characteristics of a single biomass particle ranging in size from 10 µm to 20 mm. Different subprocesses such as moisture evaporation, devolatilization, tar cracking, gas-phase reactions, and char gasification are examined. The sensitivity to the variation in model parameters, especially the particle size and heating rates, is investigated. The results obtained from this study are useful in assessing different combustion systems using biomass as a fuel. It helps to clarify the situations where the thermally thin and thermally thick cases interface. It is clear that simple models of particle combustion assuming constant particle temperature are sometimes inadequate and that for large particles a more detailed mathematical representation should be applied.

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This paper describes a novel laser diagnostic and its demonstration in a practical aero-propulsion engine (General Electric J85). The diagnostic technique, named hyperspectral tomography (HT), enables simultaneous 2-dimensional (2D) imaging of temperature and water-vapor concentration at 225 spatial grid points with a temporal response up to 50 kHz. To our knowledge, this is the first time that such sensing capabilities have been reported. This paper introduces the principles of the HT techniques, reports its operation and application in a J85 engine, and discusses its perspective for the study of high-speed reactive flows.

Reactive absorption with an aqueous solution of amines in an absorber/stripper loop is the most mature technology for postcombustion CO 2 capture (PCC). However, most of the commercial-scale CO 2 capture plant designs that have been reported in the open literature are based on values of CO 2 loadings and/or solvent circulation rates without an openly available techno-economic consideration. As a consequence, most of the reported designs may be suboptimal, and some of them appear to be unrealistic from practical and operational viewpoints. In this paper, four monoethanolamine (MEA) based CO 2 capture plants have been optimally designed for both gas-fired and coal-fired power plants based on process and economic analyses. We have found that the optimum lean CO 2 loading for MEA-based CO 2 capture plants that can service commercialscale power plants, whether natural-gas-fired or coal-fired, is about 0.2 mol/mol for absorber and stripper columns packed with Sulzer Mellapak 250Y structured packing. Also, the optimum liquid/gas ratio for a natural gas combined cycle (NGCC) power plant with a flue gas composition of approximately 4 mol % CO 2 is about 0.96, while the optimum liquid/gas ratio for a pulverized-coal-fired (PC) power plant can range from 2.68 to 2.93 for a flue gas having a CO 2 composition that ranges from 12.38 to 13.50 mol %.

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