Fundamental Processes of Solid and Liquid Biofuels Combustion

固体和液体生物燃料的基本过程燃烧木材和其他生物质燃料，无论是固体还是液体，作为“碳中性”能源都很有吸引力。它们的有效利用需要彻底了解它们的燃烧过程，该建议涉及生物燃料燃烧及其实验验证的某些方面的计算工具的开发。所有项目的共同点是需要处理具有一定复杂性的固体和液体混合物。固体生物质燃料最常在填充床中燃烧或气化：在炉排上的相当大的燃料颗粒的非流化床。这是一个复杂的过程，迄今为止还没有像许多燃烧过程那样被很好地理解。实际燃料通常是具有各种不同颗粒大小和形状的混合物，并且通常具有具有不同燃烧特性的几种组分（例如木材废料）。拟议的工作将开发在填充床燃烧的数值模型中处理这种混合物的方法，并将对一系列燃料进行实验以验证该模型。木屑等燃料颗粒也会在床层中重叠，从而显著减少可用于燃烧的表面积。将开发通过在床上进行压力损失试验来测量这种影响的方法。还将研究纤维取向（晶粒）对燃烧和热解的影响。大多数液体生物燃料，如传统的石油燃料，是具有大量组分的混合物，并且可以有效地建模为连续混合物，将它们表示为一个或多个概率密度函数，而不是离散物种。该提案将进一步发展用于模拟液体生物燃料蒸发和燃烧的连续热力学技术。特别感兴趣的两个领域是需要描述复杂混合物的化学反应动力学的方法，以模拟点火和燃烧，以及极性化合物（如许多生物燃料中发现的醇类）的非理想相平衡的处理。

Fundamental Processes of Solid and Liquid Biofuels Combustion Wood and other biomass fuels, both solid and liquid, are attractive as "carbon-neutral" energy resources. Their efficient utilisation requires a thorough understanding of their processes of combustion, and this proposal addresses the development of computational tools for some aspects of biofuels combustion and their experimental verification. Common to all the projects is the need to deal with mixtures, both solid and liquid, of some complexity. Solid biomass fuels are most often burned or gasified in a packed bed: a non-fluidized bed of fairly large fuel particles on a grate. This is a complex process that as yet is not as well understood as many combustion processes. Practical fuels are usually mixtures with a wide range of different particle sizes and shapes, and often have several components with different combustion characteristics as well (e.g. wood wastes). The work proposed will develop methods for dealing with such mixtures in a numerical model of packed bed combustion, and will conduct experiments on a range of fuels to verify the model. Particles of fuels such as wood chips can also overlap in the bed, reducing the surface area available for combustion significantly. Methods will be developed to measure this effect through pressure loss tests on the bed. The effects of fibre orientation (grain) on combustion and pyrolysis will also be investigated. Most liquid biofuels, like conventional petroleum fuels, are mixtures with large numbers of components, and may be modelled effectively as continuous mixtures, representing them as one or more probability density functions rather than in terms of discrete species. This proposal will further develop continuous thermodynamics techniques for modelling the evaporation and combustion of liquid biofuels. The two areas of particular interest are methods are needed to describe chemical reaction kinetics of complex mixtures in order to model ignition and combustion, and the treatment of non-ideal phase equilibrium for polar compounds such as alcohols found in many biofuels.