CO_(2)在单乙醇胺溶液吸收塔中的传质阻力模拟研究

Simulation study on the mass transfer resistance of CO_(2)in the monoethanolamine aqueous solution absorption tower

为了探究吸收塔内CO_(2)传质随着塔高变化情况,进一步指导吸收塔强化。将吸收塔分为“塔顶”“塔中”“塔底”3个部分,通过鼓泡吸收实验分别对“塔顶”“塔中”“塔底”处单乙醇胺(MEA)水溶液吸收CO_(2)行为进行模拟,获得不同位置的CO_(2)出口体积分数。结果表明,根据双膜理论和传递的连续性建立动力学模型对实验数据进行分析,获得模拟塔“塔顶”“塔中”“塔底”处CO_(2)的吸收速率、吸收量和传质阻力,“塔中”吸收速率是“塔顶”吸收速率的1.7倍,是“塔底”吸收速率的3.7倍;“塔中”吸收量是“塔顶”吸收量的1.7倍,是“塔底”吸收量的4.4倍;“塔底”的阻力是“塔中”阻力的6.8倍,是“塔顶”阻力的9.2倍。因此“塔顶”阻力最小,“塔中”吸收量和吸收速率最大,“塔底”阻力最大,“塔底”吸收量和吸收速率最小。吸收塔的“塔底”是CO_(2)处理能力最弱的部位,对“塔底”进行设计改造有望提高吸收塔处理CO_(2)的能力。

In order to explore the CO_(2)mass transfer situation in the absorption tower with the change of tower height,and further guide the strengthening of the absorption tower,the absorption tower was divided into three parts of"top""middle"and"bottom",the CO_(2)absorption behavior in the monoethanolamine aqueous solution at the"top""middle"and"bottom"was simulated by bubbling absorption experiments to obtain the CO_(2)outlet volume fraction at different locations.Results showed that based on the double membrane theory and the continuity of transmission,a dynamic model was established to analyze the experimental data,and the absorption rate,absorption capacity and mass transfer resistance at the simulation tower"top""middle"and"bottom"were obtained.The absorption rate at the"middle"was 1.7 times than that of the"top"and 3.7 times than that of the"bottom";while the absorption amount at the"middle"was 1.7 times than that of the"top"and 4.4 times than that of"bottom";the resistance at the"bottom"was 6.8 times than that of the"middle"and 9.2 times than that of the"top".Therefore,"top"had the least resistance,"middle"had the largest absorption amount and absorption rate,and"bottom"had the largest resistance,and"bottom"had the smallest absorption amount and absorption rate.The"bottom"of the tower is the weakest part of the absorption ability,and the design and modification of the bottom of the tower can hopefully improve the absorption ability of the absorption tower.