Fu H, Matthews M A
Department of Chemical Engineering, Swearingen Engineering Center, The University of South Carolina, Columbia, SC 29208, USA.
J Hazard Mater. 1999 Jun 11;67(2):197-213. doi: 10.1016/s0304-3894(99)00037-0.
Mathematical models are developed to compare aqueous surfactant washing to supercritical carbon dioxide (SCCO2) extraction. These two cleaning processes are potentially competitive technologies which can be used to remove oily contaminants from a solid waste. In both processes, the cleaning efficiency for a batch of waste is evaluated by quantifying the residual oil content in the treated sample. A mass transfer model is used to simulate a semi-continuous washing process, and the experimental data, obtained in a batch operation, are used to estimate the equilibrium parameters in the model. For SCCO2 extraction, a linear desorption model is used to describe the supercritical desorption of oil from the solid phase into the CO2 phase and the simulated results agreed very well with the experimental data. The oil removal in aqueous surfactant washing is viewed to be controlled primarily by the diffusional transport of oil from the interiors of the waste elements to the surface, thus, it can be significantly affected by the size of the particles. A pre-cleaning pulverization is then recommended to improve the cleaning efficiency without increasing any other operation costs. In SCCO2 extraction, the desorption of oil from the solid waste is the controlling step and consequently, the solvent flow rate has no influence on oil removal. Our theoretical studies show that the difference between the cleaning efficiencies of these two technologies is not significant, with the oil concentration in the washing products approximately 5% lower than that in the extraction products.
开发数学模型以比较水性表面活性剂洗涤与超临界二氧化碳（SCCO2）萃取。这两种清洁工艺是潜在的竞争技术，可用于从固体废物中去除油性污染物。在这两种工艺中，通过量化处理后样品中的残留油含量来评估一批废物的清洁效率。使用传质模型模拟半连续洗涤过程，并将间歇操作中获得的实验数据用于估计模型中的平衡参数。对于SCCO2萃取，使用线性解吸模型描述油从固相到CO2相的超临界解吸，模拟结果与实验数据非常吻合。水性表面活性剂洗涤中的除油主要被认为是由油从废物元件内部向表面的扩散传输控制的，因此，它会受到颗粒尺寸的显著影响。因此，建议进行预清洁粉碎以提高清洁效率，而不增加任何其他运营成本。在SCCO2萃取中，油从固体废物中的解吸是控制步骤，因此，溶剂流速对除油没有影响。我们的理论研究表明，这两种技术的清洁效率差异不显著，洗涤产品中的油浓度比萃取产品中的油浓度低约5%。
