Mass Transfer And Microscopic Flow Behavior Of Ring Random Carbon Foam Packing(RRFP-C)

The carbon foam material has the advantages of low density,high strength,high void ratio,large specific surface area and corrosion resistance,and has good application prospects in the fields of medicine,architecture and catalyst carrier.In the field of distillation,our research group combines foam materials with tower packing,and develops a series of novel packing with high mass transfer efficient.In this paper,the carbon foam material was introduced into the field of random packing,and the Ring random Carbon foam packing(RRFP-C)were developed and mass transfer performance,wetting process and wetting area were studied.The mass transfer efficiency experiment was carried out in 300 mm stainless steel distillation column.Experiments were carried out on ceramic and metal Raschig ring & RRFP-C.A system of cyclohexane n-heptane was selected to test under full reflux experiment and atmospheric pressure.The experimental results show that,on the aspects of mass transfer efficiency,RRFP-C is better than the traditional ring packing and has a wider range of operation,which is about 20% higher than traditional raschig ring.RRFP-C's HETP achieves 0.24 m at a higher flow rate.On the aspects of the pressure drop,RRFP-C shows a lower operating pressure drop.The microscopic flow behavior experiments were carried out in the laboratory.The fluid was marked by the fluorant tracing technique,and the wetting process and wetting area of ceramic and metal Raschig ring & RRFP-C were tested by high speed photography.Experiments of wetting process show that the diffusion process of liquid on the surface of unwetted annular dispersed RRFP-C is divided into three stages: vertical flow stage,lateral flow stage and stable stage.In the lateral flow stage,there is a process of liquid spreading in the inner side of the filler,which increases the wetting area on RRFP-C surface.The diffusion process on the surface of wetted RRFP-C is divided into 2 stages: diffusion stage and stable stage.In the diffusion stage,liquid spreads in the inner part of the packing,which achieves a short stable time and large wetting area.The wetting area experiment shows that the overall wetting area of the RRFP-C is more than 80%,much higher than that of the other two traditional raschig ring 10-60%.The wetting area of the surface of RRFP-C is less than 10%,and it has a better wetting distribution and stability under a large range of liquid flow.The wetting condition of RRFP-C in the top feed reach the best,and the wetting area ratio is less affected by the position of the feed point,within 10%,and the whole wetting area is kept higher than 80%.Through the study of mass transfer and flow performance of RRFP-C,the results show that RRFP-C has a high mass transfer efficiency and wide operating range and has a good wetting area and a relatively uniform distribution performance and has a broad application prospect.