Difference point stripping column sections

As in distillation, sidestreams can be introduced or sidestream products can be withdrawn at different points or stages. In distillation practice at least, it is preferable that the sidestreams introduced be approximately of the same composition as at the point or stage introduced. Again by analogy, the membrane section above the feed location may be referred to as the rectifying section, and the section below as the stripping section or vice versa. The former is the accepted convention in distillation practice, where the more-volatile component(s) move toward the top of the column, the less-volatile toward the bottom. 

The SEM pictures were shown in Fig. 3 were scale layers stripped flnm different sections of quartz rod. Fig. 3(a) was a cross sectional profile of scale from the severe scaled point. Level (1) was quartz rod substrate scale tightly appressed to level (1) was named level (2). It could be seen from Fig. 3(a) that there was no obvious interface between the scale and quartz substrate. The positive face of this scale block was shown in Fig. 3(b) and the scale stripped from the smooth scaled point was shown in Fig. 3(c). Compared with Fig. 3(b), there were less agglomerations and shorter whisker columns in Fig. 3(c). The XRD patterns were shown... 

The column has two feeds, as in Example 9.1, but in this application the feeds are of very different average boiling points, and they enter the column at about the same temperature. The oil feed has the higher boiling point and is fed at the top of the column as external reflux, while the gas mixture is fed at an intermediate tray. The top section of the column between the two feeds is the absorption section where most of the propane recovery takes place. The lower section, between the gas feed and the reboiler, is the reboiled stripping section where ethane and lighter components are stripped off as in conventional columns. 

The ratio of enthalpy differences, which appears in this equation and which we denoted q, represents the molar heat of vaporization of Hie feed divided by the molar heat of vaporization of the liquid in the column, assumed to be constant. Suppose, for example, that the feed consists of either saturated vapor or saturated liquid. Then the value of q will be 0 or 1, respectively, and for a partially vaporized feed it will be somewhere between ese two limits. The quantity q is therefore a dimensionless measure of the thermal quality of the feed. It turns out that q also enters into the construction of the locus of the points of intersection of the two operating lines of the enriching and stripping sections. That locus is represented by the expression... 

Distillation is based on the differences between the boiling points of the desired alcohol and water. The distillation column has two distinct sections, the rectifying section above the feed stream and the stripping section below the feed stream. In the rectifying section the alcohol increases in purity as it travels as a vapor to the top of the column, where it is... 

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