School of Chemical and Biomolecular Engineering, The University of Sydney, NSW 2006, Australia.
Environ Sci Technol. 2009 Dec 15;43(24):9329-34. doi: 10.1021/es902367x.
Methane constitutes 15% of total global anthropogenic greenhouse gas emissions. The mitigation of these emissions could have a significant near-term effect on slowing global warming, and recovering and burning the methane would allow a wasted energy resource to be exploited. The typically low and fluctuating energy content of the emission streams makes combustion difficult; however porous burners-an advanced combustion technology capable of burning low-calorific value fuels below the conventional flammability limit-are one possible mitigation solution. Here we discuss a pilot-scale porous burner designed for this purpose. The burner comprises a cylindrical combustion chamber filled with a porous bed of alumina saddles, combined with an arrangement of heat exchanger tubes for preheating the incoming emission stream. A computational fluid dynamics model was developed to aid in the design process. Results illustrating the burner's stable operating range and behavior are presented: stable ultralean combustion is demonstrated at natural gas concentrations as low as 2.3 vol%, with transient combustion at concentrations down to 1.1 vol%; the system is comparatively stable to perturbations in the operating conditions, and emissions of both carbon monoxide and unburned hydrocarbons are negligible. Based on this pilot-scale demonstration, porous burners show potential as a methane mitigation technology.
甲烷占全球人为温室气体排放总量的 15%。减少这些排放将对减缓全球变暖产生重大的近期影响，而且回收和燃烧甲烷将使浪费的能源得到利用。排放物流的典型低热值和波动能量含量使得燃烧变得困难；然而，多孔燃烧器——一种能够在传统可燃极限以下燃烧低热值燃料的先进燃烧技术——是一种可能的缓解解决方案。在这里，我们讨论了为此目的设计的一个试点规模的多孔燃烧器。该燃烧器包括一个圆柱形燃烧室，其中填充有氧化铝鞍座的多孔床，以及一组用于预热进入的排放物流的换热器管。开发了一个计算流体动力学模型来辅助设计过程。呈现了说明燃烧器稳定运行范围和行为的结果：在天然气浓度低至 2.3 体积%的情况下，实现了稳定的超低燃烧，在浓度低至 1.1 体积%的情况下，实现了瞬态燃烧；该系统对操作条件的干扰相对稳定，并且一氧化碳和未燃烧的碳氢化合物的排放可以忽略不计。基于此试点规模的演示，多孔燃烧器显示出作为一种甲烷缓解技术的潜力。
