Page 258 - Chemical Process Equipment - Selection and Design

3. Comparative Data ob Refrigerants"

Evaporator
Temp PFI -80 -60 -40 -20 0 20 40 80
Evaporator ammonia 5.55 10.4 18.3 30.4 48.0 73.0 107.5
pressure propylene 7.20 12.5 20.7 32.1 48.0 70.0 96.0 131
(psis) propane 5.55 9.78 16.2 25.5 38.1 56.0 80.0 '110
freon 12 2.88 5.36 9.3 15.3 23.8 35.7 51.7 72.4
Condensed Liquid Temperature 95°F; Condenser Pressure in psia:
Ammonia 197; Propylene 212; Propane 177; 12 123
I$ refrigerant/ ammonia 0.454 0.446 0.438 0.432 0.426 0.422 0.418
min/ton propylene 2.07 1.96 1.87 1.79 1.72 1.66 1.60 1.54
refrigeration propane 2.18 2.04 1.93 1.83 1.74 1.67 1.59 1.53
freon 12 5.18 4.89 4.65 4.42 4.22 4.05 3.88 3.74

CMF of ammonia 20.4 11.1 6.45 3.96 2.52 1.69 1.14
refrigerant/ propylene 27.1 15.7 9.18 5.85 3.84 2.53 1.80 1.28
m ii n/to n propane 37.4 20.0 12.0 7.29 4.77 3.12 2.13 1.50
refrigeration freon 12 59.9 31.7 18.0 10.8 6.79 4.44 3.00 2.09
Brake ammonia 4.31 3.23 2.41 1.78 1.26 0.835 0.483
horsepower/ propylene 5.00 3.96 3.10 2.35 1.74 1.20 0.830 0.485
toin refrigeration propane 4.98 3.87 3.03 2.32 1.75 1.24 0.800 0.458
freon 12 5.70 4.33 3.31 2.47 1.83 1.30 0.848 0.490
Condensed Liquid Temperature 125'F; Condenser Pressure in psia:
Ammonia 303; Propylene 314; Propane 260; Freon 12 184
Ib refrigerant ammonia 0.492 0.483 0.474 0.466 0.460 0.454 0.450
m i n/ton propylene 2.67 2.50 2.35 2.22 2.11 2.01 1.93 1.86
refrigeration propane 2.86 2.63 2.44 2.29 2.16 2.04 1.94 1.84
freon 12 6.42 5.98 5.61 5.28 5.00 4.75 4.53 4.33
CFMI of ammonia 22.0 12.0 6.97 4.26 2.72 1.82 1.23
refrigerant/ propylene 35.2 20.0 11.5 7.32 4.72 3.08 2.18 1.56
ton/ propane 50.0 25.8 15.4 9.16 5.94 3.79 2.63 1.80
refrigeration freon 12 74.0 38.8 21.7 12.9 8.05 5.21 3.50 2.42

Brake ammonia 5.68 4.38 3.33 2.54 1.90 1.38 0.952
horsepower/ propylene 7.49 5.96 4.71 3.66 2.79 2.03 1.55 1.10
ton refrigeration propane 7.47 5.85 4.60 3.59 2.81 2.07 1.50 1.03
freon 12 8.09 6.25 4.78 3.67 2.78 2.07 1.49 1.02
"The horsepowers are based on centrifugal compressor efficiencies without economizers.

Absorber @ 45 psia
95% equilibrium
0.96 MBtu/hr

Stripper @ 21 0 psia

600,000 Btu/hr 1.1 HP
Figure 8.27. An ammonia absorption refrigeration process for a load of 50 tons at
30°F. The conditions were established by Hougen, Watson, and Ragatz (Thermo-
dynamics, Wile]?, New York, 1959, pp. 835-842).

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