THE LOCAL HEAT BALANCE IN A STATIONARY FLUIDIZED-BED FURNACE BURNING BIOMASS FUELS

机译：燃烧生物质燃料的固定流化床炉中的局部热平衡

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This work investigates the influence of biomass fuel properties on the local heat balance in a commercial-scale fluidized bed furnace. Experiments with different wood based fuels were performed in the Chalmers 12MW_(th) circulating fluidized bed boiler, temporarily modified to run under stationary conditions. A two-phase flow model of the bed and splash zone is applied, where the combustion rate in the bed is estimated by global kinetic expressions, limited by gas exchange between oxygen-rich bubbles and a fuel-rich emulsion phase. The outflow of bubbles from the bed is treated as "ghost bubbles" in the splash zone, where the combustion rate is determined from turbulent properties. It is found that a large amount of heat is required for the fuel and air to reach the temperature of the bed, in which the heat from combustion is limited by a low char content of the fuel. This implies that a substantial fraction of the heat from combustion of volatiles in the splash zone has to be transferred back to the bed to keep the bed temperature constant. It is concluded that the moisture content of the fuel does not considerably alter the vertical distribution of heat emitted, as long as the bed temperature is kept constant by means of flue gas recycling.

机译：这项工作研究了生物质燃料特性对商业规模流化床炉中局部热平衡的影响。在Chalmers 12MW_（TH）循环流化床锅炉中进行了不同木材燃料的实验，暂时修改以在静止条件下运行。应用床和飞溅区的两相流动模型，其中床中的燃烧速率由全球动力学表达估计，受到富氧气泡与富含燃料乳液相之间的气体交换的限制。从床的气泡流出被视为飞溅区中的“鬼气泡”，其中燃烧速率从湍流性能确定。结果发现，燃料和空气需要大量的热量，以达到床的温度，其中来自燃烧的热量受到燃料的低炭含量的限制。这意味着从飞溅区中挥发物燃烧的大部分热量必须转回床以保持床温常数。得出结论，燃料的水分含量不会显着改变发射的热量的垂直分布，只要床温通过烟道气回收率保持恒定即可。

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《International Conference on Fluidized Bed Combustion》|2003年||共12页
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Fredrik Niklasson; Filip Johnsson; American Society of Mechanical Engineers;
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中图分类 TQ051.13-53;
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fluidized bed boiler; heat balance; biomass; combustion;

机译：流化床锅炉;热平衡;生物质;燃烧;

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1. Kinetics of the Catalytic Decomposition of N_2O over Bed Materials from Industrial Circulating Fluidized-Bed Boilers Burning Biomass Fuels and Wastes [J] . Vesna Barisic, Fredrik Klingstedt, Pia Kilpinen, Energy & fuels . 2005,第6期

机译：工业循环流化床锅炉燃烧生物质燃料和废物时床材料上N_2O催化分解的动力学
2. Experimental investigation on combustion and heat transfer characteristics in a furnace fueled with unconventional biomass fuels (date stones and palm stalks) [J] . S.-A.B. Al-Omari Energy Conversion & Management . 2006,第6期

机译：用非常规生物质燃料（大枣和棕榈秸秆）供热的燃烧和传热特性的实验研究
3. BIOMASS ENERGY FUELS CORN ETHANOL PRODUCTION: Replacing natural gas increases net energy balance, lowers costs and improves process sustainability - creating fuel from locally available feedstocks [J] . Diane Greer BioCycle: Journal of Composting & Recycling . 2007,第4期

机译：生物质能源燃料玉米乙醇的生产：替代天然气可提高净能源平衡，降低成本并提高流程的可持续性-利用当地可用的原料生产燃料
4. THE LOCAL HEAT BALANCE IN A STATIONARY FLUIDIZED-BED FURNACE BURNING BIOMASS FUELS [C] . Fredrik Niklasson, Filip Johnsson, American Society of Mechanical Engineers International Conference on Fluidized Bed Combustion . 2003

机译：燃烧生物质燃料的固定流化床炉中的局部热平衡
5. Numerical study on vaporization and burning of multi-component stationary fuel droplets and single-component convective fuel droplets both with complex configuration and variable properties. [D] . Wu, Guang. 2010

机译：具有复杂结构和可变特性的多组分固定燃料液滴和单组分对流燃料液滴的蒸发和燃烧的数值研究。
6. A health intervention or a kitchen appliance? Household costs and benefits of a cleaner burning biomass-fuelled cookstove in Malawi [O] . Katie Cundale, Ranjeeta Thomas, Jullita Kenala Malava, -1

机译：健康干预或厨房用具？马拉维清洁燃烧生物质燃料的灶具的家庭成本和收益
7. This article presents a new numerical model describing the behaviour of a thermally thick wood sample exposed to high solar heat flux (above 1 MW/m2). A preliminary study based on dimensionless numbers is used to classify the problem and support model building assumptions. Then, a model based on mass, momentum and energy balance equations is proposed. These equations are coupled with liquid-vapour drying model and pseudo species biomass degradation model. By comparing to a former experimental study, preliminary results have shown that these equations are not enough to accurately predict biomass behaviour under high solar heat flux. Indeed, a char layer acting as radiative shield forms on the sample exposed surface. In addition to this classical set of equations, it is mandatory to take into account radiation penetration into the medium. Furthermore, as biomass contains water, medium deformation consecutively to char steam gasification must also be implemented. Finally, with the addition of these two strategies, the model is able to properly capture the degradation of biomass when exposed to high radiative heat flux over a range of sample initial moisture content. Additional insights of biomass behaviour under high solar heat flux were also derived. Drying, pyrolysis and gasification fronts are present at the same time inside of the sample. The coexistence of these three thermochemical fronts leads to char gasification by the steam produced from drying of the sample, which it is the main phenomenon behind medium ablation. [O] . Pozzobon, Victor, Salvador, Sylvain, Bézian, Jean Jacques 2018

机译：本文提供了一个新的数值模型，该模型描述了暴露于高太阳热通量（高于1 / MW / m2）的热厚木材样品的行为。基于无量纲数的初步研究用于对问题进行分类并支持模型构建假设。然后，提出了一种基于质量，动量和能量平衡方程的模型。这些方程式与液体蒸汽干燥模型和假物种生物质降解模型耦合。通过与以前的实验研究进行比较，初步结果表明，这些方程不足以准确预测高太阳热通量下的生物量行为。的确，在样品暴露的表面上形成了充当辐射屏蔽层的炭层。除了这套经典的方程式之外，还必须考虑到辐射向介质的渗透。此外，由于生物质中含有水，因此还必须在炭蒸气汽化后进行连续的介质变形。最后，通过添加这两种策略，该模型能够在一定范围的样品初始水分含量下暴露于高辐射热通量的情况下，正确捕获生物质的降解。还得出了在高太阳热通量下生物量行为的其他见解。样品内部同时存在干燥，热解和气化前沿。这三个热化学前沿的共存会导致样品干燥产生的蒸汽产生焦炭气化，这是介质烧蚀的主要现象。

THE LOCAL HEAT BALANCE IN A STATIONARY FLUIDIZED-BED FURNACE BURNING BIOMASS FUELS

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