Spreadsheet Problem Solving fo r ChE Faculty Single-effect Single-effect Evaporator Design
D. E. Clough 1/19/98 Basic Data
Feed Flow Rate Feed Composition Feed Temperature
6.93 kg/s 0.14 mass fraction 21 degC
Product Composition
0.47 mass fraction
Steam Pressure Steam Temperature
100 psig 164.3 degC
Vapor Condensation Pressure Vap Vapor Condensati satio on Tem Temperatu rature re
2 psia 39 degC
Flow Rates (kg/s) Total NaOH 6.93 0.97 2.06 0.97 4.87 -- or --
Overall Material Balance
Feed Product Overall Evaporation Rate Boiling Point Elevation
69 degF
Temperature Drop Total Elevation Net Temperature Summary
W ater 5.96 1.09 4.87 20.6 degC
125.3 degC 20.6 degC 104.7 degC Solution
Saturation 59.6
39 degC
Enthalpy Balance
Stream Steam Feed Vapor Steam Condensate Product
Saturation No Temperature Composition Superheat (degC) (kJ/kg) 164.3 164.3 21 0.14 59.6 39 2573 164.3 59.6 0.47
Temperature (degC)
Evaporator Duty Ove Overall rall Heat Tra Transfe sfer Coeffic fficie ien nt Area
20979 kW 2 600 W/(m .K) 2 333.8 m 333.8 m
Steam Economy
78.9%
Capital Cost
Operating Costs Steam Cash Flow Cost of Capital 10% Inflation 3% NPV ($5,129,234)
$370,000 1990 index $473,017 $473,017 1997 index
$750,920 per year 1998 1999 2000 2001 2002 2003 2004 2005 2006 2006 2007 2007 2008 2008
($473,017) ($750,920) ($773,447) ($796,651) ($820,550) ($845,167) ($870,522) ($896,638) ($92 ($923, 3,53 537) 7) ($95 ($951, 1,24 243) 3) ($97 ($979, 9,78 780) 0) ($9,081,471)
3593 ft 3593 ft
Enthalpy (kJ/kg) 2750 76.1 2613 651 368
Flow Rate Enthalpy (kg/s) Rate (kW) 6.17 6.93 4.87 6.17 2.06
16963 528 -12716 -4016 -760 0 Overall
2
1.28 CPI
Steam Cost $1.5 per 1000 lb $1.9 pe per 1000 lb 6.17 kg/s 391586 Mlb/yr
1990 1997
Property Tables
Table Interpolation
Boiling Point Elevation
Composition (mass fraction)
Boiling Pt. Elev. (degF)
0.00 0.10 0.20 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70
0 4 14 25 35 47 65 75 88 100 120 138
data from McCabe, Smith & Harriott, p. 421
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Property Tables
Table Interpolation
Steam and Condensate Enthalpy
Index
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Temperature degF 90 95 100 110 120 130 140 150 160 170 180 190 200 210 212 220 230 240 250 260 270 280 290 300 310
Vapor Enthalpy degC BTU/lbm kJ/kg 32.2 35.0 37.8 43.3 48.9 54.4 60.0 65.6 71.1 76.7 82.2 87.8 93.3 98.9 100.0 104.4 110.0 115.6 121.1 126.7 132.2 137.8 143.3 148.9 154.4
1100.9 1103.1 1105.2 1109.5 1113.7 1117.9 1122.0 1126.1 1130.2 1134.2 1138.1 1142.0 1145.9 1149.7 1150.4 1153.4 1157.0 1160.5 1164.0 1167.3 1170.6 1173.8 1176.8 1179.7 1182.5
2560.7 2565.8 2570.7 2580.7 2590.5 2600.2 2609.8 2619.3 2628.8 2638.1 2647.2 2656.3 2665.4 2674.2 2675.8 2682.8 2691.2 2699.3 2707.5 2715.1 2722.8 2730.3 2737.2 2744.0 2750.5
Liquid Enthalpy BTU/lbm kJ/kg 57.99 62.98 67.97 77.94 87.92 97.90 107.89 117.89 127.89 137.90 147.92 157.95 167.99 178.05 180.07 188.13 198.23 208.34 218.48 228.64 238.84 249.06 259.31 269.59 279.92
134.9 146.5 158.1 181.3 204.5 227.7 251.0 274.2 297.5 320.8 344.1 367.4 390.7 414.1 418.8 437.6 461.1 484.6 508.2 531.8 555.5 579.3 603.2 627.1 651.1
Reference: McCabe, Smith and Harriott, p. 926.
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Index
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Property Tables
Table Interpolation
NaOH-H2O Solution Enthalpy
Comp. Mass Fraction
0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50
Temperature -- degF 50
90
150
200
250
18 18 17 16 17 20 22 38 64 74 112
58 55 52 49 48 49 56 68 82 112 130
120 115 108 102 99 102 108 120 137 158 180
170 160 152 147 142 143 149 162 177 196 220
223 210 200 192 187 188 191 202 220 235 263
Entries in BTU/lbm Reference: McCabe, Smith & Harriott, p. 429. Converted Table First column entries below indices are temperatures in degC. First row entries to right of indices are compositions in mass fraction. Main table entries are enthalpies in kJ/kg.
0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50
10.0 41.9 41.9 39.5 37.2 39.5 46.5 51.2 88.4 148.9 172.1 260.5
32.2 134.9 127.9 121.0 114.0 111.6 114.0 130.3 158.2 190.7 260.5 302.4
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65.6 279.1 267.5 251.2 237.3 230.3 237.3 251.2 279.1 318.7 367.5 418.7
93.3 395.4 372.2 353.6 341.9 330.3 332.6 346.6 376.8 411.7 455.9 511.7
121.1 518.7 488.5 465.2 446.6 435.0 437.3 444.3 469.9 511.7 546.6 611.7
Property Tables
300
350
265 257 242 238 235 236 238 245 259 277 297
320 306 290 280 277 276 279 282 300 318 338
148.9 616.4 597.8 562.9 553.6 546.6 548.9 553.6 569.9 602.4 644.3 690.8
176.7 744.3 711.8 674.5 651.3 644.3 642.0 649.0 655.9 697.8 739.7 786.2
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