Eclipse Engineering Guide

CHAPTER 5 – STEAM & WATER
BOILER TERMINOLOGY AND CONVERSION FACTORS
Boiler horsepower – One boiler horsepower
= 33,479 Btu/hr heat to steam
= 34.5 lb/hr of water evaporated
from and at 212°F
= 9.8 Kilowatts
Dry Steam – Steam which contains no liquid water.
Enthalpy – Heat content, Btu/lb, of a liquid or vapor.
Latent heat of vaporization – The heat required to convert a
material from its liquid to its vapor phase without raising its
temperature. The latent heat of vaporization of water at 1
atmosphere pressure and 212°F is 970.3 Btu/lb.
30
Quality – In a mixture of steam and water, the weight percentage
which is present as steam; in other words, the percent
of complete vaporization which has taken place. The quality of
saturated steam is 100%.
Saturated Steam – Steam which is at the same temperature as
the water from which it was evaporated.
Wet Steam – Steam which contains liquid water. Its quality is
less than 100%.
PROPERTIES OF SATURATED STEAM
V g,
Specific h f, h fg, h g,
Volume of Heat Content Latent Heat, Heat Content
Temperature, Pressure, psi Vapor of Liquid, of Vaporization, of Vapor
°F Absolute Gauge cu ft/lb Btu/lb Btu/lb Btu/lb
32 .089 – 3304.7 -0.018 1075.5 1075.5
40 .121 – 2445.8 8.03 1071.0 1079.0
50 .178 – 1704.8 18.05 1065.3 1083.4
60 .256 – 1207.6 28.06 1059.7 1087.7
70 .363 – 868.4 38.05 1054.0 1092.1
80 .507 – 633.3 48.04 1048.4 1096.4
90 .698 – 468.1 58.02 1042.7 1100.8
100 .949 – 350.4 68.00 1037.1 1105.1
110 1.28 – 265.4 77.98 1031.4 1109.3
120 1.69 – 203.3 87.97 1025.6 1113.6
130 2.22 – 157.3 97.96 1019.8 1117.8
140 2.89 _ 123.0 107.95 1014.0 1122.0
150 3.72 – 97.07 117.95 1008.2 1126.1
160 4.74 – 77.29 127.96 1002.2 1130.2
170 5.99 – 62.06 137.97 996.2 1134.2
180 7.51 – 50.22 148.00 990.2 1138.2
190 9.34 – 40.96 158.04 984.1 1142.1
200 11.53 – 33.64 168.09 977.9 1146.0
212 14.696 0 26.80 180.17 970.3 1150.5
220 17.19 2.49 23.15 188.23 965.2 1153.4
240 24.97 10.27 16.32 208.45 952.1 1160.6
260 35.43 20.73 11.76 228.76 938.6 1167.4
280 49.20 34.50 8.64 294.17 924.6 1173.8
300 67.01 52.31 6.47 269.7 910.0 1179.7
320 89.64 74.94 4.91 290.4 894.8 1185.2
340 117.99 103.29 3.79 311.3 878.8 1190.1
360 153.01 138.31 2.96 332.3 862.1 1194.4
380 195.73 181.03 2.34 353.6 844.5 1198.0
400 247.26 232.56 1.86 375.1 825.9 1201.0
500 680.86 666.16 0.67 487.9 714.3 1202.2
600 1543.2 1528.5 0.27 617.1 550.6 1167.7
700 3094.3 3079.6 0.075 822.4 172.7 995.2
705.47* 3208.2 3193.5 0.051 906.0 0 906.0
*Critical Temperature