The extraction of aromatics with N-formylmorpholine (NFM) has been widely used in petrochemical and coal tar industries.However, the vapor-liquid equilibrium (VLE) data of N-formylmorpholine-aromatics systems are very limited, and no isobaric VLE data can be found in literature.The VLE data of benzene-NFM system were determined by using an improved VLE equipment EC-2.The experimental VLE data were correlated with the thermodynamic models NRTL and UNIQUAC, and the corresponding binary interaction parameters for these two models were obtained.The results showed that the VLE data agreed well with the two models, and passed the thermodynamic consistency test of Herington.By comparison with these models from literature, it is found that these two models are more suitable for VLE prediction for NFM systems above 80℃.The VLE data and model parameters obtained are essential for the engineering design of N-formylmorpholine-aromatics distillation processes.
Air was fed into a packed extraction column to increase turbulence,enhance liquid droplet dispersion and surface renewal,and thus raise mass transfer area.This led to improvement of liquid-liquid contact and mass transfer.The experiments on hydrodynamics and mass transfer were carried out with air-kerosene (benzoic acid)-water system, and the effect of air agitation was investigated.It is clear from the results that the air hold-up ,dispersed phases hold-up and mass transfer coefficient increase and flooding velocity goes down while increasing superficial air velocity.The over-agitation of air can cause over-dispersion and emulsification of the dispersed phase,deterioration of mass transfer performance,and even flooding.Packing helps to break up the droplet of dispersed phase and can effectively prevent the liquid from longitudinal mixing in extraction column,so the mass transfer performance of packed column is far better than that of non-packed.
