【摘要】 为研究循环流化床锅炉炉内石灰石脱硫+炉外烟气循环流化床半干法脱硫除尘一体化系统在不同负荷下,锅炉出口和布袋除尘器出口烟气中SO₂和SO₃质量浓度的变化规律,对某300 MW循环流化床锅炉进行了试验研究。结果表明:锅炉出口原烟气中SO₂质量浓度随锅炉负荷的增加而减小,SO₃质量浓度随锅炉负荷的增加而增大;在炉内氧过量及二次风分级送入的情况下,炉温和流化速度是影响炉内SO₃质量浓度的重要因素,导致在大于75%锅炉负荷后SO₃质量浓度增加趋势明显增大,100%锅炉负荷时达到18.5 mg/m³;在炉外烟气半干法循环流化床脱硫除尘一体化系统中,消石灰、再循环脱硫灰、工艺水等的协同作用使净烟气中SO₃质量浓度降至1.4 mg/m³以下,表明炉外半干法循环流化床脱硫除尘一体化工艺具有良好的负荷适应性和脱除能力。更多还原

【Abstract】 To study the variation law of SO₂ and SO₃ concentration in the flue gas at outlet of a 300 MW circulating fluidized bed（CFB） boiler and its bag filter, where in-furnace limestone desulfurization and external semi-dry desulfurization combined with dust removal were adopted at different loads, experimental tests were conducted. Results show that with the increase of boiler load, the SO₂ concentration in raw outlet gas of boiler decreases, while the SO₃ concentration increases. In the presence of excess oxygen in the boiler and under the grading supply of secondary air, both the furnace temperature and fluidizing velocity are the main factors influencing the in-furnace SO₃ concentration, leading to the obvious increase in SO₃ concentration at the load above 75%, which gets up to 18.5 mg/m³ at 100% load. For the external flue gas sulfur/ash removal system, the combined action of slaked lime, desulfurization ash recycling as well as process water helps to reduce the SO₃ concentration to be below 1.4 mg/m³, indicating high sulfur/ash removal ability and good load adaptability of the integral semi-dry CFB system.更多还原