Effects of firing coal and biomass under oxy-fuel conditions in a power plant boiler using CFD modelling
Effects of firing coal and biomass under oxy-fuel conditions in a power plant boiler using CFD modelling
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DOI：
10.1016/j.fuel.2013.03.075
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发表时间：
2013-11-01
期刊：
影响因子：
7.4
通讯作者：
Pourkashanian, M.
中科院分区：
文献类型：
--
作者：
Black, S.;Szuhanszki, J.;Pourkashanian, M.
氧燃料燃烧是最有前途的碳捕获与封存技术之一。本研究使用商业计算流体动力学（CFD）代码，模拟了现有500mwe全尺寸燃煤公用锅炉在空气和全氧燃料条件下的煤和生物质燃烧。结果提出了传统的空气煤燃烧，对应于现有的实验数据和内部经验模型。在保持相同的热输入和出口氧气浓度的情况下，采用CFD作为预测工具，结合标准物理子模型，研究了空气-生物质、氧-煤和氧-生物质条件下燃烧的影响。研究了湿式烟气循环中氧浓度为25%和30%（体积比）的氧燃料条件。预计在空气和全氧燃料条件下燃烧生物质的效果比燃煤情况下对管壁的总传热更低，锅炉中的炉膛出口温度更低。这可能归因于大型生物质颗粒的影响，它们具有较低的总表面积，因此导致向管壁的辐射热传递减少以及灰分碳（CIA）预测的增加。对于氧煤燃烧，研究表明，传热的最佳氧浓度与空气煤密切匹配，在25%到30%之间，但对于氧生物质燃烧可能需要大于30%的值。这项研究强调了改变燃料和燃烧气氛对现有电厂锅炉传热特性的可能影响，强调了在空气和氧燃料条件下转换为生物质燃烧时可能需要进行微小的重新设计。(C) 2013 Elsevier Ltd.版权所有。
One of the most promising technologies for carbon capture and storage (CCS) is oxy-fuel combustion. This study uses a commercial computational fluid dynamics (CFD) code to simulate the firing of coal and biomass under air and oxy-fuel conditions in an existing full-scale 500 MWe coal-fired utility boiler. Results are presented for conventional air-coal combustion that corresponds well against available experimental data and an in-house empirical model. Maintaining the same thermal input and exit oxygen concentration, CFD was used as a predictive tool with standard physical submodels, to examine the effects of firing under air-biomass, oxy-coal and oxy-biomass conditions. The oxy-fuel conditions were investigated at oxygen concentrations of 25% and 30% by volume for a wet flue gas recycle. The effects of firing biomass in both air and oxy-fuel conditions are predicted to have a lower total heat transfer to the tube walls, with a lower furnace exit temperature in the boiler than the coal-fired cases. This may be attributed to the effects of large biomass particles, which have a lower total surface area and therefore causes a reduction in the radiative heat transfer to the tube walls as well as an increase in carbon in ash (CIA) predictions. For oxy-coal firing, the study suggested that the optimum oxygen concentration for heat transfer to be closely matched with air-coal, lies between 25% and 30%, but for oxy-biomass firing a value greater than 30% may be needed. This study highlights the possible impact of changing the fuel and combustion atmosphere on the heat transfer characteristics of an existing power plant boiler, underlining that minor redesign may be necessary when converting to biomass firing under air and oxy-fuel conditions. (C) 2013 Elsevier Ltd. All rights reserved.