Info

0.1 10 100 1000 Reiotive volatility of corrponent. a,

Figure 2.23 Application of d/b plots to examine nonkey component distribution in products. Depropanizer example, 20 theoretical stages, R/Rmin = 1.40.

0.1 10 100 1000 Reiotive volatility of corrponent. a,

Figure 2.23 Application of d/b plots to examine nonkey component distribution in products. Depropanizer example, 20 theoretical stages, R/Rmin = 1.40.

i i i i i i i i I_i i i I_i i i i i i i given C3/C4 split, feeding the column higher than the ideal feed point improves the light nonkey split at the expense of a worse heavy nonkey split. Conversely, feeding the column lower than the ideal feed point improves the heavy nonkey split at the expense of a worse light nonkey split.

2.5 Nomenclature 2.5.1 English Letters

B Bottom flow rate, lb-mole/h b Flow rate of a component in bottom product, lb-mole/h

D Overhead product flow rate, lb-mole/h d Flow rate of a component in top product, lb-mole/h

Emv Murphree tray efficiency, Eq. (2.33), fractional

F Feed rate, lb-mole/h

H Enthalpy, Btu/lb-mole

AH Heat added or removed, Btu/h

Hv Latent heat of vaporization, Btu/lb-mole. In Eq. (2.3) only, Hv is vapor enthalpy, Btu/lb-mole i,j Counter of the number of components

J A section identifier in a complex column

K Equilibrium lvalue, Eq. (1.1)

k Section counter in a complex column k' Section counter for second simultaneous stream at the point of heat addition or removal in a complex column

L Liquid flow rate, lb-mole/h. In Sees. 2.2.1 to 2.2.5 and 2.3.3 to 2.3.5, L specifically denotes liquid flow rate in rectifying section

I Flow rate of nonkeys in the liquid, lb-mole/h

L' Stripping section liquid flow rate, lb-mole/h

JV + 1 Number of sections in a complex column

N,n Stage number

P Flow rate of side product, lb-mole/h

P' Flow rate of stream going to interboiler or intercondenser, lb-mole/h

<7 Pound-moles of liquid introduced with the introduction of 1 lb-mole of feed

Q Heat added, Btu/h

Q Pound-moles of liquid withdrawn with the withdrawal of 1 lb-mole of side product

Q' Pound-moles of liquid per 1 lb-mole of stream going to intercon-denser or interreboiler

S Stripping ratio, V'/B

T Temperature, "F

u Mole fraction of the more volatile component in a side product u' Mole fraction of the more volatile component in stream going to intercondenser or interreboiler

V Vapor flow rate, lb-mole/h. In Sees. 2.2.1 to 2.2.5 and 2.3.3 to 2.3.5, V specifically denotes vapor flow rate in rectifying section

V Stripping section vapor flow rate, lb-mole/h

* Mole fraction of the more volatile component in the liquid (binary distillation); mole fraction of a component in the liquid (multi-component distillation)

y Mole fraction of the more volatile component in the vapor (binary distillation); mole fraction of a component in the vapor (multi-component distillation)

y* Equilibrium mole fraction of the more volatile component in the vapor y( 0) Intercept of the component balance line on the y axis of an x-y diagram z Mole fraction of the light key in the feed

2.5.2 Greek letters a Relative volatility

2.5.3 Subscripts

1,2,... Section number in a complex column

B,b Column bottom

BP Bubble point

C1(...,C6 Refers to each hydrocarbon in the worked example

D,d Column overhead product

DP Dew point e Equivalent binary of the keys

F,f Feed

HK Heavy key

HNK Heavy nonkey ij Counter of the number of components i Component balance lines intersection point int Point of intersection of the component balance line with the 4S°

diagonal

A section of identifier in a complex column Section counter in a complex column

Section counter for second simultaneous stream at the point of heat addition or removal in a complex column

Liquid

Limiting composition of a nonkey component

Light key

Light nonkey

Stripping stage

Minimum

Stage number

Number of sections in a complex column Vapor

L,l lim LK LNK

2.6 References

1. McCabe, W. L., and E. W. Thiele, Ind. Eng. Chem. 17, 605, 1925.

3. Savarit, R., Arts et metiers, pp. 65, 142, 178, 241, 266, 307, 1922.

4. Van Winkle, M„ Distillation, McGraw-Hill, New York, 1967.

5. Henley, E. J., ed., Stage wise and Mass Transfer Operations, Vols. 1 and 2, A-I.Ch.E., New York, 1980.

6. Robinson, C. S. R., and E. E. Gilliland, Elements of Fractional Distillation, 4th ed., McGraw-Hill, New York, 1950.

7. King, C. J., Separation Processes, 2d ed., McGraw-Hill, New York, 1980.

8. Brian, P. L. T., Staged Cascades in Chemical Processing, Prentice-Hall, Englewood Cliffs, N.J., 1972.

9. Gallant, R. W., Physical Properties of Hydrocarbons, Vols. 1 and 2, Gulf Publishing, Houston, Texas, 1968 and 1984,

10. Fisher, G. T., Ind. Eng. Chem. Proc. Des. Dev. 2(4), 284, 1963.

11. Ledanois, J., and C. Olivera-Fuentes, ind. Eng. Chem. Proc. Des. Dev. 23, 1, 1982.

12. Kister, H. Z., Distillation Operation, McGraw-Hill, New York, 1990,

13. Arnold, V, E., Chem. Eng., February 4, p. 59, 1985.

14. Hengstebeck, R. J., The Refining Engineer, p. C-6, November, 1957.

15. Hengstebeck, R. J., Distillation—Principles and Design Procedures, Reinhold Publishing, 1961.

16. Edujjee, H. E„ Br. Chem. Eng. 9(10), 668, 1964.

17. Granville, W. H„ Br. Chem. Eng. 9(2), 89,1964.

18. Yaws, C. L., K. Y. Li, and C. S. Fang, Chem. Eng., May 18, p. 153, 1981.

19. Kister, H. Z„ Ckem. Eng., January 21, p. 97, 1986.

20. Jenny, P. J., Trans. Am. Inst. Chem. Engrs., 35, 635, 1939.

21. Hengstebeck, R. J„ Trans. Am. Inst. Chem. Engrs., 42, 309, 1946.

22. Edmister, W. C., Petrol. Engr., p. 47, June 1948.

23. Kister, H. Z„ Chem. Eng., May 13, p. 71, 1985.

24. Hengstebeck, R. J., Chem. Eng., July 29, p. 145, 1968.

25. Hanson, D. N., and J. S. Newman, Ind. Eng. Chem. Proc. Des. Dev. 16, 223, 1977.

27. Stupin, W. J., and F. J. Lockhart, Paper presented at the AIChE annual meeting, Los Angeles, December, 1968.

28. Johnson, J. E., and D. J. Morgan, Chem. Eng., July 8, p. 72,1985.

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