氨法烟气脱硫SO2吸收传质系数研究

喷淋塔氨法脱硫技术被广泛应用于净化烟气的SO₂，传质系数是喷淋吸收塔重要的设计和运行参数，但目前文献中有关氨法脱硫传质系数的报道很少，还有待进一步研究。在喷淋塔中对氨法脱硫SO₂吸收传质过程进行了实验研究，结合对液滴和塔壁液膜运动的计算，得到不同实验条件下SO₂的吸收传质速率，并建立了氨法脱硫SO₂吸收传质系数表达式。该传质系数包含浆液pH、烟气流速u_g和液气比L/G等主要参数，能够反映不同pH、u_g和L/G条件下SO₂在单位气液接触面积上的传质速率。对比验证结果表明，该传质系数计算得到的SO₂吸收传质速率与实验值之间的相对误差小于±12%，二者能够较好地吻合。建立的传质系数表达式能够为喷淋塔氨法脱硫的优化设计和运行提供理论参考。

Investigation of mass transfer coefficient of absorption of sulfur dioxide by ammonia

The ammonia-based flue gas desulfurization (FGD) using spray scrubber is widely used for removing SO₂ from flue gas. However, the reports about mass transfer coefficient of SO₂ in the ammonia-based desulphurization process are little in the literature and a further investigation is needed, even though the mass transfer coefficient of SO₂ is much needed for optimizing the design and operation of the absorption tower of ammonia-based FGD system. On basis of experiments of absorbing SO₂ with ammonia in a lab-scale spray scrubber, the mass transfer rate per unit gas-liquid interfacial area was investigated by calculating the motion of droplets and liquid membrane. The correlation to predict the mass transfer coefficient of SO₂ absorption by ammonia was also proposed, including parameters pH, u_g and L/G. The yielding correlation could be used for quantitatively predicting the mass transfer rate per unit gas-liquid interfacial area under different operating conditions such as pH, gas flow rate and liquid-to-gas ratio. The comparison results show that the calculated SO₂ mass transfer rate agrees well with the measured data. The relative error between the calculated mass transfer rate and the measured data is within ±12%. The established mass transfer coefficient expression can provide a theoretical reference for the optimal design and operation of spray tower ammonia desulfurization.