Page 481 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

Process Safety and Pressure-Relieving Devices 447

400 Values of Coefficient C
I / k c k c k c k c
/'
348
1.02
1.32
374
318
L92
349
1.62
395
380 .,v 1.01 317• 1.31 350 1.61 373 1.91 395
1.33
1.03
1.63
319
396
1.93
375
-: ·- 1.04 320 1.34 351 1.64 376 1.94 397
1.95
1.05
1.35
1.65
321
376
352
397
o 360 / L06 322 1.36 353 1.66 377 1.96 398
1.37
398
1.97
1.67
323
353
378
1.07
/ C=52iiVk(7ffr) : �� 1.08 325 1.38 354 1.68 379 1.98 399
/ 1.09 326 1.39 355 L70 379 1.99 400
1.69
I.IO
400
IAO
356
2.00
380
3Y7
.,' Lil 328 1.41 357 1.71 381
1.72
382
1.42
329
358
1.12
/ 1.13 330 1.43 359 1.73 382
1.14
331
360
1.44
1.74
383
,- � / 1.15 332 1.45 360 1.75 384
320 1.16 333 1.46 361 1.76 384
1.17 334 J.47 362 1.77 385
10 12 14 16 18 20 1.18 335 1.48 363 1.78 386
1.19 336 1.49 364 1.79 386
Specific heat ratio, k = Cp/Cy 1.20 337 1.50 365 1.80 387
1.21 338 1.51 365 1.81 388
1.22 339 1.52 366 l.82 389
1.23 340 1.53 367 1.83 389
1.24 341 1.54 368 1.84 390
1.25 342 1.55 369 1.85 39\
1.26 343 1.56 369 1.86 391
1.27 344 1.57 370 1.87 392
Figure 7-25. Constant "C" for gas or vapor related to spe- 1.28 345 1.58 371 1.88 393
cific heats. By permission, Sizing, Selection and Installa- 1.29 346 1.59 372 l.89 m
tion of Pressure-Relieving Devices in Refineries, Part I 1.30 347 1.60 373 1.90 394
"Sizing and Selection," API RP-520, 5th Ed., July 1990. 'Interpolated value, since C becomes indeterminate as k approaches l .00.
CONSTANT BACK PRESSURE SIZING FACTOR
Kb
- l'!!m��fflfflmmmm�rmfflmmmm1"4'+i++1fflmmmm1"4'+�fflfflfflfflffl�
1 1
w +r-Fc.+-+-+++-+-H·++-++++-1-+-+-++++-+-+-<- � •++-++-1-t-t-++++-t-+-t-++++-1-+-+ � ++-1-++-1-++-++++-1-t-t-++++-1-t-t-++-rl-1-H,+++++-t-1-H++-i-+-t+-1-n1
a:: .j..--J_,
::, 1.0 ,·.
Cl) i$�- -
Cl) 'r+..-+-,- � , .-+-,--++++-t-+-1-1-+-+-l-t-+-1++++++,1-t-t-++++-t-+-1-+++-+-t-+-1-++-t-�++lr++
9
l.t.l UJ · l1r� - ·. f�Hfi�-ffff00Mffi1!ffi:fffiffiitfiffi:I!!ltmlafflruffl:mmmeanffifml
a: a::
�t · 8 +:_, �-i-hc++-'-+++HH++·H-l-H++++++H-+++++HH++-H-l-HH4++++HH++++H-.'++++l-Hl+++l-l-HI-N++++�H++++rH�t-t-HI
::,0..
-,-i--·-,•-++-+++.-++-1 � HHH++++HH++++l-HHH++l-HHH++++HH++++t+-1-++++l-HrH++++-l-rl+t-++-H-+ � ···+rHrrt++-r-i-HH+ttl
�< ::r:j=- � +++- � ++++++-+-++- �� -++++++++++++-+-++- � H-H-++++++++++++-+-++- � H-H-1-++ � - � -+++++''k-+-+-+-++- � ++--HI
O..ID ,7 � i--'-----+-'-r- � -r++-+-t-+-1-+++-+-t-+-1+++++-Hl-t-t-H-+-t-+-+-t ��� -t-t-+-1-++++t-+-1+++++-+- � -++++·t-+-1-l-r+-1- � IC,-,.++ � r ........ '-t----t-1� ·_...
�.... !---;-:.- � -++++-t-+-irrt,+++-r+t++++t+,-+++++-t-H-+++++-HH++++-rH-H+t-t+,HH � +-ri-H+++-t-r-H+-t--rl-t-H-+-t-t--h_,_,,rr++--h 1 +++1
U::, tt--.-,+-- � ++,-++-++++1-+-1++++rH-++·t++-+-11-t-t+++-t-;-+-1++++rH � ,++++-1-+-1++++H-+-H � +· �� .+r-a++-+-1-+++-t-+-t-rh+ � +•r-l+
<o .s......,. . � , -1-->-r-1-+-H-+-H+-t-+-t-H-t-H-t-H-t-tt+tt+tt++++++-H-+-H-+-H-+tt+tt+tt+tt+tt+rtt-H+�H-T-H-T- . '-t-l-r-t+-�H+1H+1-HI
IIJ .-+·--r-'-+--++-+-H�H��+-+-t-+-1-+++-+-t-+-1+++++-H++-+->-+-+-t-+-1-+++-+-ri�-'-+++-+-Hi-+----H-�r�++�++-+-+-+-+-++++-t-+-t-H-i--�-++-+-�+++++--HI
Figure 7-26. Constant backpressure sizing factor, Kb, conventional valves-vapors and gases. By permission, Teledyne Farris Engineering Co.