Page 404 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

372 Applied Process Design for Chemical and Petrochemical Plants

Ejector Suction Pressure, mm. Hg. Abs.
100 --===:::::J==::r:::r::::::i::r:1::::r:i::::i:::====:i::::::J::::::J � ;::J::r:r: � oto1====0jo=2=0jot3:::to=ot5rojoj1joj1=====0E2:::::oi3:::::J=oi5:rot1rii 1 0
1- �+-f-Plj---+--+-+-+-+-Hl+l---+--�-+-+-l--�-+-l l,000
I
70
1--,, __ ....1....._�--4---4---l--+-Jl..-l--l----4--.j.._.--i---l--l..-l--'�' " ........i-1-� ' ---'=--- 1 -.l.._1,-+-+-+4-+-l---+--�-+---l--+--l--l--l--l700
' ,
Four Stage ,cl6)
, Six Stage c (6)
50 ,_ /100%Air lwo Stage,nc(3)(5) r--, " 500
j \ Three Stage, Borometri· � <J..\ c � r-,
30 'lntercondensers(5) .... .,..,"- �"- r,.:- 300 ...
1--t...... ) I I I II II '% � , 0- 1 -....... ...
r-,
Single Stog_e, "' .
'"
20 I ---......... V 1\.,,100% Air in Mixture f\. � " I A' nc (1)(2 )15) +..: �� ...- .' ,1--+-J�++++---+---1-l---4---+-+-l-+-I 200-:
q-? ��
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e I'\ � � I'._ I � I\ Five Stage, c (6) ::::E
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= \ " r'\r,.. r-, r,.., �'$ � " <
� 10 " '- ,---l----1f--l--4- � +-1- � ---1-----1"1-1,Four Stage ,c (6) 100 ;e
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E
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< 7 l------1---+-���'>i-1-+-P,,..o;:--'�..,....-+-l-+-1--P..i-l����--�-+--l---+4-�' .�+-' ... ......._:-----+�---+-lr,+-+-+-+-+-1-l 70 ..
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vi � V � tur· � � . � � 2\.---+--+-+-+--+-+4j,1n-1--......,_, � ' All Curv:S �-., .&:,
e
.,; 3 "r0-. 30 ,::,
.&:, "�10%A�........._ [f. Two Stage, ,, 11 far 100% Air
I ........._ in Mixtur)'""" ,
Barometric
..., M 2 1----4--+--l--l--+-H-+-l-----".;.:-.........:..:.:;:=.=+ � 1-l'-..."""4 � tercondenser (4)(5) I'....,"\ ,"\ � 20 .,,.
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a,
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·5 � ..... t-...t-...t,.,.- 10%Air in I�" � �' a:
e
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c:,
a: 1 'r-......._ "' Mixture I ,, �
e 1.0 10 en
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c:, t----+--+--+-+-+-t-i-+-t-----+--+--+-+-+-+-t-+t---+- , -+--+--+-+-t-+++---1-----11--+-+-..P.�-
vi 0.7 t-----+--+---+--+1 Steam Pressure = JOO psig.
t-----+--+---+--+1 Condensing Curves based on 85° F Water, Correction is < 10% for 70 • F.
0.5 1-----+--+---+--+1 For Air Quantities between 10% and 100%, Requirements Located by Proportion. 1-1---4---1---1---+.4-1--+-<
1----+---+--l--H Mixtures Assumed to be Air and Water Vapor, if other Vapors or Gases Convert
to Air Equivalent.
0.3 1-----4----1---+.---+-1 c =Condensing, with Barometric lntercondenser.
nc = Non-Condensing.
0.2
2 3 5 7 10 20 30 50 70 100 200 300 500 700 1,000
Ejector Suction Pressure, mm. Hg. Abs.
Figure 6-25. Estimating steam requirements for ejectors.
Rating of the two stage non-condensing ejectors is han- Example 6-11: Size Selection and Utilities For Two-Stage
dled in the same manner as for a single stage ejector, Ejector With Barometric Intercondenser
using Figures 6-27 A and B, and Table 6-10.
Figures 6-28 A, B, C, D and E give representative esti- Total mixture to be handled = 40 lbs/hr
mating data for two stage ejectors with barometric inter- Pounds of air in mixture = 14 lbs/hr
condenser. Suction pressure = 1.5 in. Hg abs
Steam pressure at ejector nozzle = 150 psig
Size selection: locate size at intersection of ejector suc-
tion pressure and capacity on Figure 6-28A.
Size selection, using Figure 6-28A: 2 inch (inlet and
Steam consumption: Use Figure 6-28B; for Kuse Fig- outlet connections)
ure 6-28C
Steam consumption:
(6-22)
W', = 5.55 (Figure 6-288)
'\<\\n = 40
Water consumption: K == 0.67, (Figure 6-28C) at W /vVm = 15/40 = 0.375
3
F == 0.88 (Figure 6-28D)
GPM (approximate) = 0.06 W, w, == 5.55 ( 40) (0.67) (0.88)
Minimum GPM = 10 == 131 lbs steam/hr