Cesário M T, Brandsma J B, Boon M A, Tramper J, Beeftink H H
Department of Food Science, Wageningen Agricultural University, The Netherlands.
J Biotechnol. 1998 Jun 30;62(2):105-18. doi: 10.1016/s0168-1656(98)00052-2.
Hydrophobic pollutants in waste gases are difficult to remove with the conventional biological treatment techniques because of the slow gas/water mass transfer rate. A two-stage system with a water-immiscible solvent as intermediate liquid was developed. This system consisted of a packed absorber for transfer of the model pollutant, ethene, from gas to solvent and a stirred-tank reactor (mixer) for solvent/water transfer and subsequent degradation by Mycobacterium parafortuitum. The solvent FC40, a perfluorocarbon, was recycled between these two compartments. The stability of the system was shown during a run of 10 days. The elimination efficiency was found to be a function of the solvent flow: 9% and 15% elimination were obtained at solvent flows of 6 x 10(-8) m3.s-1 and 11.3 x 10(-8) m3.s-1, respectively. Ethene removal remained constant at increasing solvent hold-ups up to 50% (v/v). In spite of the low elimination efficiencies caused by an inefficient use of the column, the feasibility of the system to remove ethene has been demonstrated. The system's performance was described by a steady-state mathematical model. Simulated ethene removal efficiencies agreed well with the experimental data. Based on this, the model was used to optimise the dimensions and operating conditions. Furthermore, the model was used to compare the performance of the combined system (PA/MS) with the performance of a similar system without solvent. It was found that the use of solvent as intermediate liquid can improve substantially the removal efficiency of hydrophobic gaseous pollutants compared with the system without solvent. This is dependent however, on the solubility of the pollutant in the solvent, on the dimensions of the system and on the operating conditions.
由于气/水传质速率缓慢，传统生物处理技术难以去除废气中的疏水性污染物。为此开发了一种以水不混溶溶剂为中间液体的两级系统。该系统由一个填充吸收器和一个搅拌釜式反应器（混合器）组成，填充吸收器用于将模型污染物乙烯从气相转移到溶剂中，搅拌釜式反应器用于溶剂/水的转移以及随后由偶然分枝杆菌进行降解。全氟碳溶剂FC40在这两个隔室之间循环。在为期10天的运行过程中，该系统的稳定性得到了体现。发现去除效率是溶剂流量的函数：在溶剂流量分别为6×10⁻⁸ m³·s⁻¹和11.3×10⁻⁸ m³·s⁻¹时，乙烯的去除率分别为9%和15%。在溶剂滞留量增加至50%（v/v）时，乙烯的去除率保持恒定。尽管由于柱体使用效率低下导致去除效率较低，但该系统去除乙烯的可行性已得到证明。通过稳态数学模型描述了该系统的性能。模拟的乙烯去除效率与实验数据吻合良好。基于此，该模型用于优化系统尺寸和操作条件。此外，该模型还用于比较组合系统（填充吸收器/搅拌釜式反应器）与无溶剂类似系统的性能。结果发现，与无溶剂系统相比，使用溶剂作为中间液体可显著提高疏水性气态污染物的去除效率。然而，这取决于污染物在溶剂中的溶解度、系统尺寸和操作条件。
