where Tj = hot fluid inlet temperature, °F T2 = hot fluid outlet temperature, °F T3 = cold fluid inlet temperature, °F T4 = cold fluid outlet temperature, °F AT] = larger temperature dif
Trang 1Table 3-3 Tube Materials
Sweer Senice Glycol, MEA, and Sulfinol
Temperatures above ~20°F, A-2 14 ERW or A- 1 79 (seamless)
shell-In the basic heat transfer equation it is necessary to use the log meantemperature difference In Equation 2-4 it was assumed that the two flu-ids are flowing counter-current to each other Depending upon the con-figuration of the exchanger, this may not be true That is, the way inwhich the fluid flows through the exchanger affects LMTD The correc-tion factor is a function of the number of tube passes and the number ofshell passes
Figures 3-10 and 3-11 can be used to calculate a corrected LMTDfrom the formula
where Tj = hot fluid inlet temperature, °F
T2 = hot fluid outlet temperature, °F
T3 = cold fluid inlet temperature, °F
T4 = cold fluid outlet temperature, °F
AT] = larger temperature difference, °F
AT2 = smaller temperature difference, °F
LMTD = log mean temperature difference, °F
F = correction factor
(text continued on page 64)
Trang 262 Design of GAS-HANDLING Systems and Facilities
Figure 3-10 LMTD correction factors (From Gas Processors Suppliers Association,
Engineering Data Book, 9th Edition.)
Trang 3Figure 3-11 LMTD correction factors (From Gas Processors Suppliers Association,
Engineering Data Book, 9th Edition.)
Trang 464 Design of GAS-HANDLING Systems and Facilities
(text continued from page 61)
To size a shell-and-tube exchanger, first the duty is calculated Then it
is determined which fluid will be in the shell and which in the tube, and aheat* transfer coefficient assumed or calculated A choice is made of thenumber of shell and tube passes to get a reasonable LMTD correctionfactor (F), and a corrected LMTD as calculated from Equation 3-1.Next, a tube diameter and tube length are chosen The number of tubesrequired is calculated by:
where N = required number of tubes
q = heat duty, Btu/hr
U = overall heat transfer coefficient, Btu/hr-ft2-°F
LMTD = corrected log mean temperature difference, °F
Once the number of tubes is determined, the flow velocity of fluidinside the tubes should be checked, using the criteria set forth for flow inpipes in Chapter 8 of Volume 1
Trang 5DOUBLE-PIPE EXCHANGERS
A double-pipe exchanger is made up of one pipe containing the tubefluid concentric with another pipe, which serves as the shell The tube isoften finned to give additional surface area The double-pipe exchangerwas developed to fit applications that are too small to economicallyapply the requirements of TEMA for shell and tube exchangers
Double-pipe exchangers can be arranged as in Figure 3-12 such thattwo shells are joined at one end through a "return bonnet," which causesthe shell-side fluid to flow in series through each of the two shells In thisconfiguration, the central tube is bent or welded into a "U" shape, withthe U-bend inside the return bonnet, The principal advantage to this con-figuration is that a more compact exchanger can be designed, thus sim-plifying installation
A variation of the U-tube exchanger is the hairpin style of exchanger
In the hairpin exchanger, multiple small tubes are bent into a "U" shape
in place of the single central tube This variation allows for more surfacearea to be provided in the exchanger than would be obtained with a sin-gle tube U-tube exchangers may be designed with or without fins.The advantages of double-pipe exchangers are that they are cheap andreadily available, and because of the U-tube type of construction, thermalexpansion is not a problem Double-pipe exchangers are normallydesigned and built in accordance with the applicable requirements ofTEMA Thus, they can be applied to most services encountered in oil andgas production facilities as long as the required surface area can be fitinto the physical configuration of the exchanger Although they can bebuilt in almost any size, double-pipe exchangers are most frequently usedwhen the required surface area is 1,000 ft2 or less
PLATE-AND-FRAME EXCHANGERS
Plate-and-frame exchangers are an arrangement of gasketed, pressedmetal plates aligned on carrying bars and secured between two covers bycompression bolts The pressed metal plates are corrugated in patterns toprovide increased surface area, to direct the flow in specific directions,and to promote turbulence The plates are gasketed such that each of the
(text continued on page 72)
Trang 6on next pagf)
Trang 7Heat Exchanger Tube Count
1912 2189
2489
4 12 16 36 68 100 128 176 234 302 376 460 530 632 736 858 976 1098 1242 1386 1618 1878 2134 2432
2792 2752
3527 1 3477 3414
Outside Packed Floating Head
No of Passes 1
10 19 38 70 109 130 187 241 313 384 469 544 643 744 859 973
1 1 1 8 1253 1392 1616 1870 2145 2411 2733 3400
2 10 18 36 66 98 126 176 236 298 368 449 529 616 732 835 959 1093 1224 1359 1602 1833 2107 2395 2683 3359
4 4 12 28 56 92 112 160 220 276 344 430 500 600 704 812 926 1054 1184 1318 1552 1800 2060 2344 2642 3294
1 — ' '
"U"-Tube
No of Passes 2 3 7 16 28 56 57 83 110 145 180 220 253 307 360 415 477 538 609 683 800 927 1061 1205 1366
1699 j
4 2 4 12 26 40 52 74 102 134 170
1 Shell
210 244 290 342 402 458 520 592 662 776 900 1032 1178 1334 1668
l.D, (Inches) 5.047 6.065 7.981 10.02 12.00 13.25 15.25 17.25 19.25 21.25 23.25 25.00 27.00 29.00 31.00 33.00 35.00 37.00 39.00 42.00 45.00 48,00 51,00 54.00 60.00
Fixed Tube Sheet
No of Passes
! 14 22 42 71 106 130 184 237 296 361 434 507 596 689 790 906 1031 1152 1273 1485 1721 1968 2221 2502 3099
2 14 19 38 68 102 124 169 228 290 354 420 489 585 679 775 891 1003 1134 1259 1461 1693 1941 2187 2465 3069
4 8 16 36 60 92 114 160 212 272 336 408 476 562 660 756 860 976 1090 1222 1434 1650 1902 2134 2414 3010
Outside Packed Floating Head
No of Passes ]
10 19 37 61 92 121 163 212 268 335 416 475 556 653 756 859 978 1106 1218 1426 1652 1894 2142 2417 2990
2 6 14 30 56 90 110 152 202 262 330 395 466 554 642 734 848 959 1081 1208 1399 1620 1861 2101 2379 2957
4 4 12 28 48 76 100 140 188 244 308 380 452 528 620 720 818 932 1054 1174 1376 1586 1820 2060 2326 2906
"U"-Tube
No, of Passes 2 3 5 14 28 43 53 74 100 127 157 194 226 269 316 366 419 475 537 600 703 816 935 1061
4 2 4 12 22 36 48 68 92 120 150 184 216 262 306 354 404 458 520 582 682 792 916 1038
1198 1170 |
1496 1468 |
(table continued on next page)
Trang 8Table 3-4 (Continued) Heat Exchanger Tube Count
(table on ne\l fmsffi
3/4" O.D Tubes on 1 " C Pilch 3/4" O,D Tubes on 1 " Pilch
No of Passes 1
12 16 32 52 81 97 140 188 241 296 356 414 482 570 658 742 846 952 1062 1232 1424 1636 1845
2 6 16 28 52 78 94 132 178 224 280 344 406 476 562 640 732 831 931 1045 1222 1415 1634 1832
2080 | 206f
4 4 12 24 52 76 88 124 172 216 276 332 392 468 548 640 732 820 928 1026 1218 1386 1602 1818 2(W4
i i 25X2 :56(- i J55n
"U"-Tube
No of Passes 2 3 4 12 22 34 45 64 88 112 138 170 200 236 277 320 362 418 470 524 till 710 812
«26 1042 1298
4 2 4 10 20 34 44 60 84 108 134 166 194 230 272 312 360 406 462 520 602 700 802 910
Shell
! l.D.
(Inches) 5.047 6.065 7.981 10.02 12.00 13.25 15.25 17.25 19.25 21.25 23.25 25,00 27.00 29.00 31.00 33.00 35.00 37.00 39.00 42.00 4500
48 OT
51 00 HH2 1 i MOO
i 1
1282 \ J W.OO
Fixed Tube Sheet
No of Passes 1
12 21 37 61 97 113 156 208 256 314 379 448 522 603 688 788 897 1009 1118 1298 1500 1714
2 10 18 32 54 90 108 146 1%
244 299 363 432 504 583 667 770 873 983 1092 1269 1470 lh81
4 8 16 28 48 84 104 136 184 236 294 352 416 486 568 654 756 850 958 1066 1250 1440 1650 1Q« j i<)03 1 1868 217- 135 2'Wn
l
2692 2»ol j 2h\2
Outside Packed Floating Head
No, of Passes 1
12 16 32 52 81 97 140 188 241 300 359 421 489 575 660 749 849 952 1068 1238 1432 1644 1864 209X 2600
2 10 12 28 46 74 92 134 178 228 286 343 404 472 556 639 728 826 928 1041 1216 1407 1611 183"
1062
4 8 8 24 40 68 84 128 168 216 272 328 392 456 540 624 708 804 908 1016 1196 1378 1580 1804 2026 i Ii60 ; 2520
"U"-Tube
No of Passes 2 2 5 12 21 33 43 62 87 109 136 167 195 234 275 313 360 409 464 518 610 706 804
4 2 4 10 18 32 40 58 82 104 130 160 190 226 266 304 350 398 452 508 596 692 788
917 [ i)02 ' 1018 i )2t)2 j !2"2
Trang 9Heat Exchanger Tube Count
1" O.D Tubes on 1-1/4" A Pitch ]» O,D» Tubes on M/4" a Pitch
1 904
Outside Packed Floating Head
No of Passes 1
7 10 22 38 56 73 100 130 170 212 258 296 355 416 475 544 619 696 768 908 1041 1189 1348 1531 1906
2 4
10 18 36 52 72 98 126 162 201 250 294 346 408 466 529 604 679 753 891 1017 1182 1337 1503 1879
4 4 4 16 28 48 60 88 116 148 188 232 276 328 392 446 510 582 660 730 860 990 1152 1300 1462 1842
"U"-Tube
No of Passes 2 0 2 7 13 22 28 43 57 76 96 116 135 161 189 222 254 289 330 370 436 505 578 661 748 933
.„._,„ , IL ^
4 0 2 4 12 18 26 38 52 68 88no128 152 182 212 246 280 316 356 418 490 562 642 726 914
Shell 1,0.
(Inches!
5.047 6.065 7.981 10.02 12.00 13.25 15.25 17.25 19.25 21.25 23.25 25.00 27.00 29.00 31.00 33.00 35.00 37.00 39.00 42.00 45.00 48.00 51.00 54.00 60.00
Fixed Tube Sheet
No of Passes 1
9 12 22 38 56 69 97 129 164 202 234 272 328 378 434 496 554 628 708 811 940 1076 1218 1370 170!
2 6 12 20 38 56 66 90 124 158 191 234 267 317 370 428 484 553 621 682 811 931 1061 1202 1354
4 4 12 16 32 52 66 88 120 148 184 222 264 310 370 428 484 532 608 682 804 918 1040 1192 1350
1699 1 1684
Outside Packed Floating Head
No of Passes 1
5 12 21 32 52 61 89 113 148 178 216 258 302 356 414 476 542 602 676 782 904 1034 1178 1322 1654
2 4 6 16 32 52 60 84 112 144 178 216 256 300 353 406 460 530 596 649 780 894 1027 1155 1307 1640
4 4 4 16 32 44 52 80 112 140 172 208 256 296 338 392 460 518 580 648 768 874 1012 1150 1284 1632
^
"IP-Tube
No of Passes 1 2
0 2 6 12 19 25 36 49 64 83 100 120 142 166 145 221 254 287 322 379 436 501 573 650 810
L.- „, ,_
4 0 2 4 10 18 24 34 48 62 78 98 116 138 166 192 218 248 280 314 374 434 494 570 644 802
(table continued on next page)
Trang 10Table 3-4 (Continued) Heat Exchanger Tube Count
1 " O.D Tubes on ! - 1 /4* O Pitch 1 - 1 /4" O,D Tubes on 1 -9/16" A
1220 j 119') i tl/6
1389 j B59 [mo
1714 1 !69i ! 1064
Outside Packed Floating, Head
No of Passes 1
5 12 21 32 52 61 89 113 148 180 221 261 308 359 418 477 540 608 674 788
<JIO 1037 1181 ]4T7
2 4 10 18 32 46 58 82 112 138 174 210 248 296 345 401 460 526 588 654 765 885 1018 1160
4 4 8
16 28
40 56 76 104 128 168 200 236 286 336 388 448 508 568 640 756 866 1000 1142
1107 j 1292
1658 ! 162A j l:W4
"U"-Tube
No of Passes 2 0 2 5 12 18 25 35 48 62 78 100 116 141 165 191 220 249 281 315 372 436 501
%9
4 0 2 4 10 16 22 32 44 60 76 94 110 134 160 184 212 242 274 310 364 426 490
She!!
I.D.
(Inches) 5.047 6.065 7.981 10.02 12.00 13.25 15.25 17.25 19.25 21.25 23.25 25.00 27.00 29.00 31.00 33.00 3500 37.00 39.00 4200 45.00 -iS.OO
558 J , 51.QO
646 | 632 1 i 54.00
802 i 788 1 ' ftOM
Fixed Tube Sheet
No of Passes 1
7 8 19 29 42 52 69 92 121 147 174 196 237 280 313 357 416 461 511 596 687 790 896 1008 1241
2 4 6 14 26 38 48 68 84 110 138 165 196 226 269 313 346 401 453 493 579 673
4 4 4 12 20 34 44 60 78 104 128 156 184 224 256 294 332 386 432 478 570 662
782 1 758 S" 7 ! j 860
494 [ 968 C'4* 1210
Outside Packed Floating Head
No of Passes ]
0 7 14 22 37 44 64 85 109 130 163 184 221 262 302 345 392 442 493 576 657 7%
859
2 0 6 14 20 36 44 62 78 102 130 152 184 216 252 302 332 183 429 479 557 640 745 Kit,
4 0 4 8 16 28 36 48 72 96 116 144 172 208 242 280 318 364 412 460 544 828
~2«
^2
0^4 j ysg j «j4(, l!9M 1 195 1 > '?H
"U"-Tube
No of Passes 2 0 0 3 7 11 16 24 32 43 57 69 81 98 116 134 155 17K 202 226 267 313 560
41 1 46^
SB,-
4 0 0
2
6 10 14 22 30 40 52 66 76 92 110 128 148 172 194 220 260
*06 3*»()
400 ! 4*a I 1
-TO i
Trang 11Heat Exchanger Tube Count
1 - ! /4" O.D Tubes on 1 -9/ 1 6" D Pitch ! - 1 14" O.D, Tubes on 1 -9/ 1 6" O Pitch
4 4 4 12 16 32 42 52 76 88 120 144 164 202 230 268 302 338 384 434 502 588 676 756 856
1070 j 1054
Outside Packed Floating Head
No of Passes 1
0 6 12 21 32 38 52 70 89 112 138 164 193 224 258 296 336 378 428 492 570 658 742 838 1042
2 0 6 12 16 32 38 52 70 88 112 138 164 184 224 256 296 332 370 426 492 566 648 729 823 1034
4 0 4 12 16 32 32 52 68 88 112 130 156 i84 216 256 282 332 370 414 484 556 648 722 810
"U"-T«be
No, of Passes 2 0 0 3 6 10 14 21 28 37 49 62 70 88 100 116 136 156 174 198 236 276 314 356 404
4 0 0 2 4 10 14 18 28 34 48 60 68 88 98 116 134 148 174 196 228 268 310 354 402
she!!
1 1ST (inches) 5.047 6.065 7.981 10.02 12.00 13.25 15.25 17.25 19.25 21.25 23.25 25.00 27.00 29.00 31.00 33.00 35.00 37.00 39.00 42.00 45.00 48.00 51.00 54.00
Fixed Tube Sheet
No of Passes 1
5 6 13 24 37 45 60 79 97 124 148 174 209 238 275 314 359 401 442 522 603 682 777 875
2 4 6 10 20 32 40 56 76 94 116 142 166 202 232 264 307 345 387 427 506 583 669 762 857
4 4 4 8 16 28 40 56 76 94 112 136 160 192 232 264 300 334 380 424 500 572 660 756 850
Outside Packed Floating Head
No of Passes 1
0 5 12 21 32 37 52 70 90 112 140 162 191 221 261 300 341 384 428 497 575 660 743 843
2 0 4 10 18 28 34 52 70 90 108 138 162 188 215 249 286 330 372 412 484 562 648 728 822
4 0 4 8 16 28 32 48 64 84 104 128 156 184 208 244 280 320 360 404 472 552 640 716 812
'
"U"-Tube
No of Passes 2 0 0 2 6 10 13 20 28 37 48 60 71 85 100 114 134 153 173 195 228 271 309 354 401
4 0 0 2 6 10 12 18 26 34 44 56 68 82 96 110 128 148 168 190 224 264 302 346 392
Trang 1272 Design of GAS-HANDLING Systems and Facilities
Figure 3-12 Double pipe exchanger.
(text continued from page 65)
two fluid streams flow in parallel between alternate pairs of plates Inaddition to directing the flow patterns, the plate gasket keeps the fluidsretained within the plate pack Figure 3-13 shows a plate-and-frameexchanger
Major advantages of plate-and-frame exchangers include the ing: They have a low cost (especially for corrosive service), they arelighter and smaller than comparable shell-and-tube heat exchangers, fullcounter current flow and an LMTD correction factor are not required,and a close temperature approach is possible Standard components allowsimple stocking of spare parts, low maintenance, easy accessibility, andeasy expansion by adding more plates Metal plate-and-frame exchangersare particularly attractive for seawater and brackish water services How-ever, because of the design of plate-and-frame exchangers, wherein flu-ids are separated and retained across gasketed surfaces, they are limited
follow-to moderate temperature and pressure applications In addition, someoperators do not allow the use of plate-and-frame exchangers in hydro-carbon service or limit their use to pressures below 150 psig to 300 psigand temperatures less than 300°F Plate-and-frame exchangers cannot beused for high viscosity liquids and slurry/suspended solids
Because the plates are made of thin pressed metal, materials resistant tocorrosive attack can be easily selected Plates are standard and mass-pro-duced Specific applications are dealt with by changing plate arrangements.Stainless steels, monel, titanium, aluminum bronze, and other exotic metals
Trang 13Figure 3-13 Pfote-and-frame exchanger (Courtesy of Tranter, Inc.)