用修正的E-L模型描述二元VOCs气体在活性炭上的吸附平衡
Modified E-L model to correlate the adsorption equilibrium of binary VOCs gases on activated carbon
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摘要: 对不同VOCs气体二元吸附平衡进行了研究。结果表明，对于甲苯-苯、甲苯-乙酸乙酯、甲苯-丙酮、丙酮-乙酸乙酯及苯-丙酮二元吸附体系，吸附过程存在置换现象，即随着高沸点组分在床层内吸附量的逐渐增加，相对挥发性大的低沸点组分更易脱附，出现高沸点组分置换低沸点组分的现象，表现为被置换组分的穿透曲线上出现峰值；但对于苯-乙酸乙酯二元体系，由于沸点相近，吸附过程没有明显的置换现象。将活性炭对吸附质吸附量的大小与亲和系数相关联，通过引入抑制因子建立了修正的E-L模型，该模型对不同VOCs二元体系平衡吸附量的预测值与实验值吻合较好，其对二元体系中单组分和总吸附量预测的平均误差分别为9.6%和6.2%。Abstract: The binary adsorption equilibrium of different VOCs gases was studied. Results show that for the binary adsorption systems， as of toluene-benzene， toluene-ethyl acetate， toluene-acetone， acetone-ethyl acetate and benzene-acetone， displacement phenomena take place in the adsorption processes. With the increase of adsorbed amount of high boiling point components in adsorber， the low boiling point components desorb more easily， and displacements from high boiling point components to low boiling point components occur， with the breakthrough curves of components displaced having peaks. But for the benzene-ethyl acetate， there is no clear displacement effect because of their close boiling point. Associating the adsorption amount of activated carbon to adsorbate with affinity coefficient， the modified E-L model was proposed to predict VOCs binary adsorption equilibrium by introducing depression factor. The values of prediction by the modified E-L equation for amount of single component and the total in binary system show good agreement with the experimental results， with average errors about 9.6% and 6.2%， respectively.
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Key words:
- VOCs /
- adsorption /
- displacement phenomenum /
- affinity coefficient /
- E-L model
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