In this study, 11 coal mono-combustion tests and four co-combustion tests of coal and tannery sludge were conducted on a 35 kW fluidized-bed combustor. The combustion behavior and emission characteristics of the fuels were investigated on a bubbling fluidized bed (BFB) and a circulating fluidized bed (CFB). The effects of an excess air ratio, primary air rate, secondary air ratio, and fuel type on flue gas emissions were studied. The results showed that the fluidization status and temperature distribution had direct influences on CO emission. Sufficient fluidization and high temperature effectively reduced CO emission. NO_x emission was relatively sensitive to the excess air ratio and increased with increasing excess air ratio. By comparing BFB and CFB, we found that CFBs have an advantage in optimizing combustion and controlling emissions by enhancing mixing and increasing freeboard temperatures. The Cr speciation and distribution among different ash types were extensively investigated in four co-combustion tests. The results showed that the distribution modes of Cr in BFBs and CFBs were different and determined by separate fluid dynamics modes of sludge ash particles in the combustor. The extent of Cr oxidation in ash in CFB tests was higher than that in BFB tests, particularly for bottom ash and heat exchanger ash, due to longer residence times in high-temperature regions.

中文翻译：

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台式流化床燃烧器中制革污泥的共燃烧：气体排放和铬的分布与形态

在这项研究中，在一台35 kW流化床燃烧器上进行了11次煤炭单燃烧试验和4次煤和制革污泥的联合燃烧试验。在鼓泡流化床（BFB）和循环流化床（CFB）上研究了燃料的燃烧行为和排放特性。研究了过量空气比，一次风量，二次风量和燃料类型对烟气排放的影响。结果表明，流化状态和温度分布对CO的排放有直接影响。充分的流化和高温可有效减少CO排放。NO _X排放对过量空气比相对敏感，并随着过量空气比的增加而增加。通过比较BFB和CFB，我们发现CFB通过增强混合和增加干舷温度在优化燃烧和控制排放方面具有优势。在四种混合燃烧试验中，对Cr的形态和分布进行了广泛的研究。结果表明，Cr在BFBs和CFBs中的分布方式是不同的，并且是由燃烧器中污泥灰分颗粒的单独流体动力学模式决定的。CFB试验中灰分中的Cr氧化程度高于BFB试验中的Cr氧化程度，特别是对于底部灰分和热交换器灰分，因为在高温区域的停留时间更长。