Page 101 - Fluid Catalytic Cracking Handbook

78 Fluid Catalytic Cracking Handbook

Because V is positive:

%C A = 20.16

Because w is positive:

10,000
%C R =820xw-(3xS) + -
MW

10,000
%C R = 820 x 0.0226 - 3 x 0.48 +
430

The API method is a generalized method that predicts mole fraction
of paraffinic, naphthenic, or aromatic compounds for an olefin-free
hydrocarbon. The development of the equations is based on dividing
the hydrocarbon into two molecular ranges: heavy fractions (200 <
MW < 600) and light fractions (70 < MW <200). Appendix 7 contains
API correlations applicable to the FCC feed.

Example 2-4

Use the feed property data in Example 2-1 to calculate MW, RI (20r
X A, X N, and X p, employing API correlations (see Appendix 7).

Calculate MW:

MW = a x exp(b x MeABP + C x SG + d x MeABP x SG)
e
x (MeABP) x (SG/

Where:
Constants a = 20.486
b = 1.165 xlO" 4
c = -7.787
d = 1.1582xlO" 3
e = 1.26807
f = 4.98308