year. If the last plate added to the column just earns the required capital charge, then ψ = on 2 6 6 e If the extract composi6. tion is set at 1 1 % by the azeotrope, then Ε = 2.35. Substituting in Equation 2, 266 _ (1 - 2.35) In 2.35 2.55 X 10» " 2.35- + 1
or η = 10.
Finally, consider the distillation column. Figure 3 shows the varia tion of annual distillation cost as the function of tower diameter for several distillate compositions. The optimum occurs between 5 1 / 2 and 6 feet. A diameter of 6 feet was selected since this requires less capi tal than the 5l/2 foot diameter. Using the 6-foot tower diameter, Figure 4 shows the annual cost with the effect of the lost acid added in vs. XD. A mole fraction of 0.0002 acetic acid in the solvent is the optimum. The major operating costs of an extraction process are associated with the distillation step. For this ex ample : Acid not recovered in extractor = $300 per year Acid not removed from solvent = $2200 per year Steam and cooling water costs = $51,500 per year An extraction process, in essence, substitutes one distillation system for a more costly distillation system.
specialists in
FEON
LIQUID SOLIDS
NATURAL AND MAN-MADE FILTER MEDIA
separation by Centrifugal Extrac tion · Pressure Leaf and Continuous Vacuum or Pressure Filtration · Filter Media
FABRIC CONSTRUCTION DETAILS ARE NOT ENOUGH! CORRECT DESIGN AND FIT AFFECT FILTER MEDIA LIFE AND PERFORMANCE FEON manufactures correctly designed • Anode
Literature Cited (1) Eaglesfield, P., Kelly, Β. Κ., Short, J. F., Ind. Chemist 29, 243 (1953). (2) Mayfield, F. D., Church, W. L., I N D . ENG. C H E M . 44, 2253 (1952). (3) Treybal. R. E., " L i q u i d Extraction," McGraw-Hill, New York, 1951.
bags and
•
Centrifugal
•
Dust tubes
diaphragms
liners
• Plate and frame filter
covers
• Pressure leaf discs • Pressure leaf sacks •
Vacuum disc sector bags
•
Vacuum drum covers, belts,
•
Yardage produced
or slit to
blankets width
See complete data in the FEON section in Chemical Engi neering Catalog, or write Dept. IEF-460 for Bulletin A180. Our authors like to hear from readers. If you have questions or comments, or both, send them via The Editor, l/EC, 1155 16th Street N.W., Washington 6, D.C. Letters will be forwarded and answered promptly.
A
DIVISION
OF
American Machine and Metals,Inc. EAST MOLINE, ILLINOIS
FEON®
Circle No. 6 on Readers' Service Card VOL. 52, NO. 4
·
APRIL 1960
53 A
