循环流化床富氧燃烧SO_2排放和石灰石脱硫特性研究

Study on SO_2 Emission and Limestone Desulfurization Characteristics for Oxy-fuel Circulating Fluidized Bed Combustion

在50kW循环流化床燃烧试验台上进行了大同煤在O2／CO2气氛下未添加石灰石和添加石灰石的富氧燃烧试验，试验各工况进口的氧气浓度为25％～50％，燃烧温度为850-950℃。试验研究的目标是获得燃烧温度和进口氧气浓度等参数对循环流化床富氧燃烧过程中SO2的排放特性和石灰石的脱硫特性的影响。试验研究表明：未添加石灰石时，SO2的排放量随着燃烧温度的升高而升高，随着进口氧气浓度和过氧系数的升高而降低。在相同[Ca]／[S]情况下，石灰石的最高脱硫效率所对应的燃烧温度在900℃。随着进15氧气浓度的增加，石灰石的脱硫效率显著提高，在[Ca]／[S]为3的条件下，进口氧气浓度从25％增加到50％，石灰石的脱硫效率从39．0％增加到83．5％。

Experiments with and without limestone addition were carried out in a 50 kW circulating fluidized bed （CFB） combustor under the O2/CO2 atmosphere. The combustion temperatures were within the range of 800- 950℃, and the inlet oxygen concentrations was within the range of 25%-50%. SO2 emission and the limestone desulfurization characteristics were studied. Without limestone addition, SO2 emission increases with the increase in combustion temperatures and decreases with the increase in inlet oxygen concentration and oxygen excess. With the same [Ca]/[S] molar ratio, the optimum combustion temperature to achieve the highest desulfurization efficiency is 900℃. As the oxygen concentration increased, the desulfurization efficiency is increased. At a [Ca]/[S] molar ratio of 3, the desulfurization efficiencies increases from 39.0% to 83.5% as the inlet oxygen concentration increased from 25% to 50%.