The novel SiC foam valve tray was made of thin slices of SiC foam material with a high specific surfacearea. Hydrodynamic performances of the novel SiC foam valve tray were studied with air-water system at atmos-pheric pressure. These performance parameters included pressure drop, entrainment, weeping and clear liquidheight. The mass transfer efficiency of the SiC foam valve tray was measured in laboratory plate column. Comparedwith the F1 float valve tray, the dry pressure drop was decreased about 25%, the entrainment rate was about 70%lower at high gas load, the weeping was much better, and the mass transfer efficiency was far higher. Thus, theoverall performance of the novel SiC foam valve tray was better than that of F1 float valve tray.
In this study,a suitable CFD(computational fluid dynamics)model has been developed to investigate the influence of liquid height on the discharge coefficient of the orifice-type liquid distributors.The orifice flow in different diameters and liquid heights has been realized using the shear stress transport(SST)turbulence model and the Gamma Theta transition(GTT)model.In the ANSYS CFX software,two models are used in conjunction with an automatic wall treatment which allows for a smooth shift from a wall function(WF)to a low turbulent-Re near wall formulation(LTRW).The results of the models coupled with LTRW are closer to the experimental results compared with the models with WF,indicating that LTRW is more appropriate for the prediction of boundary layer characteristics of orifice flow.Simulation results show that the flow conditions of orifices change with the variation of liquid height.With respect to the turbulence in orifice,the SST model coupled with LTRW is recommended.However,with respect to the transition to turbulence in orifice with an increase in liquid height,the predictions of GTT model coupled with LTRW are superior to those obtained using other models.
以环戊烷/苯二元物系为例,采用动态模拟软件Aspen Plus Dynamics,对差压热耦合精馏的动态控制性能进行研究与分析。根据其工艺流程特点与分离操作要求建立了一种合理的控制方案。同时,对进料的流量、温度和组成扰动进行分析,考察塔顶、塔釜产品组成和流量等对进料扰动的闭环响应特性,分析该控制方案下差压热耦合精馏工艺对不同干扰因素的抗干扰性能和动态稳定特性。结果显示,该流程动态可控性强,各指标均能在干扰施加后较短时间内达到稳定,对各项干扰的稳定性能良好。
