To separate pure alcohol from an alcohol-water mixture, it is necessary to add a third non-toxic component such as ethylene glycol, to increase the volatility of the alcohol; this makes it possible to obtain pure alcohol as a dome product in a distillation column. A mixture of 68% alcohol and 32% water is fed to the tower, which gives a bottom with 17.5% alcohol, 7.9% water and 74.6% ethylene glycol. (The percentages are weight percent) Make the flow diagram, label and state degrees of freedom.
a) what mass flow rate of ethylene glycol must be fed to the column to produce 1250 cm³ / h of pure alcohol in the dome?
b) what percentage of fed alcohol is obtained as absolute alcohol?
c) would it be appropriate to feed a low concentration of ethanol?

To separate pure alcohol from an alcohol-water mixture, it is necessary to add a third non-toxic component such as ethylene glycol, to increase the volatility of the alcohol; this makes it possible to obtain pure alcohol as a dome product in a distillation column. In one of these processes, a mixture of 68% alcohol and 32% water is fed to the tower, which gives a background with 17.5% alcohol, 7.9% water and 74.6% Ethylene glycol. Make the flow diagram with a ruler, labeling and state degrees of freedom. 

a. What mass flow rate of Ethylene Glycol must be fed to the column to produce 1250 cm3 / h of pure alcohol in the dome?

b. What percentage of fed alcohol is obtained as absolute alcohol?

c. Would it be appropriate to feed a low concentration of ethanol? Justify your answer
Density data
Ethanol = 785 kg / m³
Ethylene glycol = 1110 kg / m³

Answer rating: 100% (QA)

Feed Composition 68 alcohol and 32 water Bottoms composition 175 alcohol 79 water a... View the full answer