PACKING MATERIALS Study in a 5.1-Cm.
Fractionating Column M. R. E N S K E , S. LAWROSKI, RND C. 0.TONGBERG The Pennsylvania State College, State College, Pa.
possible, the middle portion of the vapor-liquid diagram should be used. In ?a-heptane-methylcyclohexane mixtures differencesof analysis due to refractive index readings only 0.0002 a art may, when still concentrations of n-he tane or distillate concentrations o r methylcyclohexane are ohtained, cause $iffelences of eight theoretical plates when these concentrations lie near the ends of the va r liquid diagram. 4. components of the binary mixture should be pure. 5. A sufficient number of tests should he made to ensnre t,he reliability of the vas,.l,e
B-T+EL?MOCOUPLE
FIGURE 1. DIAGRAM OF COLUMN
The column used in this study is shown in Figure 1. The still was of the thennosiphon type and was heated by a 2500-watt immersion heater. Connections to the column were made by flexible metal hose. The column itself was a piece of 5.1-cm. diameter Pyrex glass pipe 2.9 meters (114 inches) long. The packing \vas supported by a cone made of Monel metal scroen.
PREVIOUS study (3) of packing mat e r i a l s was mainly concerned with columns having an inside diameter of 1.57-2.03 em. (0.62-0.80 inch). E a r l i e r data on 6.1-cm. (%inch) diameter columns awe incomplete. It was considered necessary to make a complete study of 5.1-cm. diameter columns since they are widely used in laboratory and pilot plant w o r k , and since, in addition, the data would be valuable in the general problem of the relation hetween efficiency and column diameter. It is necessary in any study concerning the testing of fractional distillation columns t.o observe as closely as possible certain fundamental rules. These are as follows: 1. Ahinarymixture whose v a p o r - l i q u i d equilibrium data are known should he wed. If the number of theoretical dates is ealeu-
used.
2. The hinary mixt.ure should give results at least a p p r o x i m a t e l y bhe same as other hinary mixtures. If the binary mixture is new. it should he eomoared in B distillation column with one of the'weil-known binary mixtures. 3. The ori inal concentration of the binary mixture shoulf be chosen so that at equilibrium the concentration of the less volatile component in the distillate or the more volatile component in the still is not too smsll. That is, whenever
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PIOURE 2. S o m 297
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OF
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m PACKLVQ USED
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INDUSTRIAL AND ENGINEERING CHEMISTRY
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VOL. 30, NO. 3
Efficiency Tests NO.
Time be- -Velocity tween Liquid Test Tests at No. Listed b. p.
Hr.
1 3 4 5 6 7
IIB. 11 13 15 16 17
18
Vapor
-n-HeptanePresBotsure Top tom Drop 001. col.
IA. 33.5(1.1) 24.5(0.8) 13.5(0.45)
Mole % Open Column
