Page 189 - Applied Process Design For Chemical And Petrochemical Plants Volume III
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66131_Ludwig_CH10E 5/30/2001 4:33 PM Page 152
152 Applied Process Design for Chemical and Petrochemical Plants
Because this rate is so close to the previous G s of 24,000, p c 0.867 psia at 97°F
it is reasonable to assume that the h o value will be close p g 32.0 0.867 31.133 psia
also. Use h o 70.0.
31.133 30.058
Latent heat, , at 130°F 1,020.0 Btu/lb p gf 30.2 psia
31.133
Assume condensate temperature, t c 98.5°F 2.3 log
30.058
P c at 98.5°F 0.907 psia
P g 32.5 0.907 31.593 5.41 1.942 0.867
701125 972 118211,022.92a b
£ 30.2 § 14.7
a b
31.593 30.27 14.7
P gf 31.6
31.593 1,140197 92.32
2.3 log
30.27
1,960 3,540 5,350
h o (t g t c ) K G M V (p v p c ) h io (t c t w ) 5,500 5,350
(See the previous note regarding h io .) Close enough check.
701130 98.52 5,500 5,350
U t 5425
2
5.41 12.223 0.9072 5,425
118211,0202 1,140198.5 932 U 166 Btu>hr 1ft 21°F2
2
£ 31.6 § 14.7 125 92.3
14.7
Interval 115°F—104°F
2,210 4,140 6,270 Point at 104°F
6,350 6,270 t g 104°F
p v 1.069 psi at 104°F
Close enough check (slightly 1%). p g 31.0 1.069 29.931 psia
6,350 6,270 314,730
U t 6,310 t¿ w 91.1 90.05°F, close enough check to 90°F
2 299,00112
6,310
U 170 Btu>hr 1ft 21°F2 New gas rate 970(14) 34.6(18) 14,223 lb/hr
2
130 93
Note that this is the same as the previous interval; the
Interval 125°F—115°F
difference is discussed there. Using Kern’s outline, this
t g 125
effect is as discussed and not as demonstrated here. In
p v 1.942 psia at 125°F
p s 32.0 1.942 30.058 psia this case, the difference is negligible.
213,940
t w 93.0 1from previous interval2 92.3°F Use h o 65
1299,0002112
Latent heat at 104°F 1034.9 Btu/lb
Assume condensate temperature, t c , of 91.7°F
New gas rate (970)(14) (46.8)(18) - 14,442 p c 0.736 psia at 92°F
14,442 p’ g 3.10 0.736 30.264 psia
2
G s 23,100 lb>hr 1ft 2
0.624
30.264 29.931
p gf 30.0
This is still not enough change in G s from 24,000 to 30.264
2.3 log
justify a calculation of a new h o . Use of the water vapor 29.931
flow leaving the assumed interval means the actual G s 5.41 1.069 0.736
through that interval will be equal to or greater than 65(104 92) 118211,034.92
£ 30.0 § 14.7
the value for conditions at 115°F. This value is on the
14.7
safe side for h o .
1,140(91.7 90)
Latent heat at 125°F, 1022.9 Btu/lb 800 1120 1940
Assume condensate temperature of t c 97.0°F 1920 1940