- p)= to find >*?ds/ f#om Fi/#e 1
ρLρ7
2/"$ lb+ft#
(dsg
186 gpm+ft2
(dsg O
1$0
(dsg
3"$/
1/$"8 gpm+ft2
(sin/ ρ> and t$e specified toe# spacin/ inpt CAF0 elo f#om Fi/#e
CA-3 CA- O
Rnl& applicabl
0.412
3"812
CA-
3"$/
3"#/1 ft+s
'sing (t from the nomograph method for a one pass tra& F9"2/ ft and a two -P7 O 9 -P7 O 9
9"/ 6"/ -P7
+ +
1 2
for a one pass tra& for a two pass tra& $/"/ ft
one pass tra&
##"6/ ft
two pass tra&
'sing !uation 19"16, the acti)e area can be found" AA.
AA. or
/3"83 ft2
one pass tra&
##"9# ft2
two pass tra&
%he area of the downcomer can be found using !uation 19"1$" Jf it is less th double A(., whiche)er is smaller" A(.
9"10 ft2
A(. + AA.
3"1$ one pass 3"26 two pass
Jn both cases, the downcomer areas are sufficientl& large"
must be at least
Now the cross sectional area of the tower can be found using !uation 19"19 A%.
0$"6# ft2
one pass tra&
/2"20 ft2
two pass tra&
Another method to find the cross sectional area of the tower is !uation 19"2 A%.
29"6#109$ ft2
%he larger of the two A%. )alues is used" Jn this case, it will be the ones calc %he diameter of the column can be calculated b& !uation 19"21" (
9"#/ ft $"10 ft
one pass tra& two pass tra&
A comparison of the different calculated diameters follows"
Met$od
me# Estimated of ,asses *iamete#
C -actor L Nomograp Nomograp (etailed (etailed
1 2 1 2
131 118 93 112 9$
in the ngineering (ata *oo5 as published b& the Gas Processor Suppliers Association as a ser)ice to the gas p eets based on the GPSA ngineering (ata *oo5 sample calculations, the use of such information is )oluntar& a onableness of factual or scientific assumptions, studies or conclusions, or merchantabilit&, fitness for a particul mitation, those resulting from lost profits, lost data or business interruption arising from the use, inabilit& to , r ther broad assumptions Fincluding but not limited toT temperatures, pressures, compositions, imperial cur)es, si
ing three methods"
"
3 and inpt C.
ion 19"1#"
than #3
ft#+s
inpt t$e toe# diamete# elo
han 13 ft han 123 in han 18 ft han 10$ in
er was found"
.16 and inpt it elo.
19.17.
where
ρ) V
13 lb+ft# and should be V 3"0
ass tra& F6"1 ft
an 11M of AA., use either 11M of AA. or
11M of AA.
"
ulated from !uation 19"19"
ocessing industr&" All information and calculation formulae has been compiled and edited in cooperation with G d the GPA and GPSA do not guarantee the accurac&, completeness, efficac& or timeliness of such information" K r purpose or nonLinfringement of intellectual propert&" eference to or reliance on the information in thes Publication, whether based on warrant&, contract, tort or an& oth te conditions etc and do not replace detailed and accurate (esign ngineering ta5ing into account actual process
s Processors Association FGPA" ference herein to an& specific commercial product, calculation method, process, or ser)ice b& tradeLname, trade r legal theor& and whether or not ad)ised of the possibilit& of such damages" conditions, fluid properties, e!uipment condition or fowling and actual control setLpoint deadLband limitations"
ar5, and ser)ice mar5 manufacturer or otherwise does not constitute or impl& endorsement, recommendation or f
)oring b& the GPA and+or GPSA"
Example 19-4
-ind the tra& efficienc& of the column in xample 19L2"
-igure 19"1$ will be used to estimate a plate efficienc&" %his needs the relati)e )olatilit& and the )iscosit& of the 5e& component at a)erage column conditions" %a)g O F%top D %bottom + 2 %a)g
1$/ -
Jt is gi)en that at 1$/ -, the )iscosit& of the feed is 3"360 cp and the a)erage : is 1"$/8" B :
3"360 cp 1"$/8
%o use -igure 19"1$, the product of these two is needed" product
3"181
-rom the figure, the efficienc& was estimated to be $3M" %he number of actual tra&s can be found with this number as follows" %he method below counts the reboiler as a stage" Ntra&s O Ftheoretical tra&s L 1 + efficienc& Ntra&s
2/
%he sample calculations, e!uations and spreadsheets presented herein were de)eloped using examples published i hile e)er& effort has been made to present accurate and reliable technical information and calculation spreadshe %he Calculation Spreadsheets are pro)ided without warrant& of an& 5ind including warranties of accurac& or reas Jn no e)ent will the GPA or GPSA and their members be liable for an& damages whatsoe)er Fincluding without li %hese calculation spreadsheets are pro)ided to pro)ide an QRperational le)el of accurac& calculation based on ra
Application of 19-4
%his will find the tra& efficienc& of a column" (se#-ente#ed data is in %!)* +E* An a)erage temperature of the column is needed"
%top
120 -
% bottom
20 -
%a)g O F
123
%a)g
must be less than %bottom D
2/3
+
2
1$/ -
At t$e a"e#a/e tempe#at#e find t$e "iscosit and t$e #elati"e "olatilitof t$e 5e co
μ :
0.076 cp
Kelati)e )olatilit& must be less than 13
1.84
%o use -igure 19"1$, the product of these two is needed" product O
3"360
product
3"181
1"$/8
(se Fi/#e 19.18 it$ t$e ao"e p#odct and find t$e t#a efficienc. Ente# it elo.
ε
3"$
Should be less than 1
o! enter t"e n#m$er of t"eoretical tra%s in t"e col#mn $elo!. &"e n#m$er of act#a Ntheoretical trays
Ntra&s O F Ntra&s
'1
21
L
1 +
3"$
2
n the ngineering (ata *oo5 as published b& the Gas Processor Suppliers Association as a ser)ice to the gas proc ets based on the GPSA ngineering (ata *oo5 sample calculations, the use of such information is )oluntar& and nableness of factual or scientific assumptions, studies or conclusions, or merchantabilit&, fitness for a particular itation, those resulting from lost profits, lost data or business interruption arising from the use, inabilit& to , refe ther broad assumptions Fincluding but not limited toT temperatures, pressures, compositions, imperial cur)es, site
ponent and ente# t$em elo.
l tra%s !ill $e calc#lated.
essing industr&" All information and calculation formulae has been compiled and edited in cooperation with Gas he GPA and GPSA do not guarantee the accurac&, completeness, efficac& or timeliness of such information" Kefe urpose or nonLinfringement of intellectual propert&" rence to or reliance on the information in thes Publication, whether based on warrant&, contract, tort or an& other l conditions etc and do not replace detailed and accurate (esign ngineering ta5ing into account actual process co
rocessors Association FGPA" rence herein to an& specific commercial product, calculation method, process, or ser)ice b& tradeLname, trademar egal theor& and whether or not ad)ised of the possibilit& of such damages" ditions, fluid properties, e!uipment condition or fowling and actual control setLpoint deadLband limitations"
, and ser)ice mar5 manufacturer or otherwise does not constitute or impl& endorsement, recommendation or fa)o
ring b& the GPA and+o
Example 19-
-ind the diameter for a pac5ed tower using 2W plastic Pall rings for the column in xample 19L#" %he g for that problem are copied below" 6381$ ft#+h
apor rate
19"/01 ft#+s
apor densit& 7i!uid rate
# lb+ft# 1193 gpm
7i!uid densit& 7i!uid surface tension
2$"$ lb+ft# #"# d&ne+cm
tra& spacing
28 inches
Also gi)en B
3"360 cp 3"/ in ;2R+ft pac5ing
HP
-rom -igure 19"2/, the pac5ing factor F- p for the specified pac5ing is 20" - p
20
-igure 19"20 can now be used" %he bottom axis is defined b& F 7 p + G p s!rt F @ ) + @7" 7 p+ G p can be .7 OF 1193 gpm 1$"$ lb+ft # 03 min+h + F6"8$ gal+ft # .7
268939 lb+h
.G O 6381$ ft #+h # lb+ft # .G
bottom axis of -igure 19"20
2112/8 lb+h
3"823
'sing 3"823 on the bottom axis, following the graph up to the specified pressure drop, the left axis can %he left axis is e!ual to a large e!uation that includes Gp, which can be sol)ed for" left axis
3"32/
Gp
1"09# lb+ft2s
%he cross sectional area of the column can be found b& ta5ing the mass of the gas flowrate and di)iding b& Gp and the con)ersion between seconds and hours" Ac
#8"0/8331 ft2
%he diameter of the tower can be found using the e!uation for area of a circle" (%
0"08 ft
%his would li5el& be rounded to 6 ft
%he sample calculations, e!uations and spreadsheets presented herein were de)eloped using examples hile e)er& effort has been made to present accurate and reliable technical information and calculatio %he Calculation Spreadsheets are pro)ided without warrant& of an& 5ind including warranties of accur Jn no e)ent will the GPA or GPSA and their members be liable for an& damages whatsoe)er Fincluding %hese calculation spreadsheets are pro)ided to pro)ide an QRperational le)el of accurac& calculation
i)en data
Application of 19- %his will find the diameter of a pac5ed tower" (se#-ente#ed data is in %!)* +E*. 70418 ft#+h
apor rate apor densit& 7i!uid rate
3 lb+ft# 1190 gpm
7i!uid densit& 7i!uid surface tension
28.8 lb+ft# 3.3 d&ne+cm
tra& spacing
24 inches
Also gi)en B
0.076 cp 0. in ;2R+ft p
HP
(sin/ Fi/#e 19.2 find t$e pac5in/ facto#
- p ubstituted with . 7 + .G"
-igure 19"20 can now be used" %he bottom axi .7 OF .7 .G O .G
horiUontal axis of -igure 19"20 be found"
26
1193 268939 6381$ 2112/8
3"823
(sin/ t$e ao"e "ale on t$e $o#i@ontal axi left axis is e!ual to a large e!uation that inclu
left axis
0.024
G p
1"0/9
%he cross sectional area of the column can be di)iding b& Gp and the con)ersion between se Ac O Ac
2112/8 #/"#0$/92
%he diameter of the tower can be found using (%
6.71
Kound this up to the nearest foot" ublished in the ngineering (ata *oo5 as published b& the Gas Processor Suppliers Association as a s spreadsheets based on the GPSA ngineering (ata *oo5 sample calculations, the use of such informat c& or reasonableness of factual or scientific assumptions, studies or conclusions, or merchantabilit&, fit without limitation, those resulting from lost profits, lost data or business interruption arising from the ased on rather broad assumptions Fincluding but not limited toT temperatures, pressures, compositions,
19"/01 ft#+s
ac5ing
should be between 3"23 to 3"03 in" ;2R+ft pac5ing
s is defined b& F 7 p + G p s!rt F @ ) + @7" 7 p+ G p can be substituted with . 7 + .G" gpm 1$"$ lb+ft # 03 min+h + F6"8$ gal+ft # lb+h ft#+h
#
lb+ft #
lb+h
.ust be less than 13
/o to Fi/#e 19.26 and ente# t$e "e#tical axis "ale elo. %he es Gp, which can be sol)ed for"
lb+ft2s
ound b& ta5ing the mass of the gas flowrate and conds and hours" +
1"0/9
ft2 he e!uation for area of a circle" ft
r)ice to the gas processing industr&" All information and calculation formulae has been compiled and edited in c ion is )oluntar& and the GPA and GPSA do not guarantee the accurac&, completeness, efficac& or timeliness of su ness for a particular purpose or nonLinfringement of intellectual propert&" se, inabilit& to , reference to or reliance on the information in thes Publication, whether based on warrant&, contr imperial cur)es, site conditions etc and do not replace detailed and accurate (esign ngineering ta5ing into acco
operation with Gas Processors Association FGPA" h information" Keference herein to an& specific commercial product, calculation method, process, or ser)ice b& t ct, tort or an& other legal theor& and whether or not ad)ised of the possibilit& of such damages" nt actual process conditions, fluid properties, e!uipment condition or fowling and actual control setLpoint deadLb
radeLname, trademar5, and ser)ice mar5 manufacturer or otherwise does not constitute or impl& endorsement, rec
and limitations"
mmendation or fa)oring b& the GPA and+or
Example 19-6
-ind the optimum heat exchanger for a )ertical thermos&phon application gi)en it must produce 83,$33 lb %he pressure of the column is 26/ psig, has an isothermal boiling point of 22$ -" %he energ& for the reboil steam at 12/ psig" %he recirculation ratio should be at least 81" %ube (ata Jnner (iameter Surface Area
3"02 in 3"190# ft2+ft 3"#32 in2
Jnternal %ube Area apor (ensit&
2"26 lb+ft#
7i!uid iscosit& 7i!uid Specific Gra)it&
3"1 cp 3"8#
An energ& balance should be calculated" 'sing thermod&namic data
nthalp& of li!uid butane F22$ -, 293 psia
281 *tu+lb
nthalp& of )apor butane F22$ -, 293 psia
##$ *tu+lb
%he energ& needed to ma5e 83,$33 lb+ )apor I O m H; I
#9/6033 *tu+h
%o find how much steam is needed nthalp& of steam at gi)en conditions mO I+ ; m H%
$0$ *tu+lb
8//9 lb+h steam 12/ -
%he maximum energ& flux is 12333 *tu+ft 2 A O I + flux A
#29"$ ft2
%his is the area that the heat exchanger must pro)ide" 'sing the specification for the surface area and assu length, the number of tubes can be found" Jll start using 10 ft, 12 ft, and 13 ft long tubes"
10 ft
7ength of %ube 12 ft
N O re!uired surface area + Flength of tube surface area of tube N 13/ tubes 183 tubes
13 ft
10$ tubes
'sing !uation 19"26, the static pressure of the reboiler leg can be found" )) O 1 + @) ))
3"883/ ft#+lb
3"883/ ft#+lb
3"883/ ft#+lb
3"3#6# ft#+lb
3"3#6# ft#+lb
3"3#6# ft#+lb
)7 O 1 + @7 )7
%he weight of the recirculated li!uid can be found b& multipl&ing the )apor mass b& 8 Fthe minimum reci .7
10#233lb li!uid+hr
10#233 lb li!uid+hr
10#233 lb li!uid+hr
ith this, the total )olume of the reboiler outlet can be found" 7 O .7 )7 7
03$2 ft#
03$2 ft#
03$2 ft#
)
16968 ft#
16968 ft#
16968 ft#
%otal )olume
283/0 ft#
283/0 ft#
283/0 ft#
) O .) ))
%he specific )olume of the outlet can now be found using the total )olume and the total mass" )o O o + .o )o
3"1169 ft#+lb
3"1169 ft#+lb
3"1169 ft#+lb
Now that )o has been obtained, the static pressure of the reboiler leg can be found using !" 19"26"
P
1"/9 psi
1"19 psi
3"99 psi
Now the frictional resistance can be found" hen added to the static pressure, this will gi)e the total resist the frictional resistance to flow, the area of flow must be found" %his is a t O Nt at + 188 at
3"223 ft2
3"298 ft2
3"#/2 ft2
%he mass )elocit&, Gt, can be found b& di)iding the mass flowrate b& the area of the tube" Gt
920#/1 lb+hr ft 2
09860# lb+hr ft 2
/6$909 lb+hr ft 2
3"282 fth+lb
3"282 fth+lb
3"282 fth+lb
3"3/2 ft
3"3/2 ft
3"3/2 ft
Con)erting the )iscosit& units B Con)erting the diameter of the pipe (
Now the Ke&nolds number can be found" Ke O ( G t + B Ke
19666/
18$##1
12#039
'sing a .ood& plot, the friction factor can be found" f
3"333126 ft2+in2
3"3331#/ ft2+in2
3"33318$#
%he a)erage specific gra)it& can be found" sa)g
3"2##
3"2##
3"2##
'sing *ernoullis e!uation the pressure drop can be found" HP
2"66 psi
1"28 psi
3"69 psi
%he total resistance to flow can be calculated b& adding the frictional resistance and static resistance" %otal HP %he dri)ing force can be calculated
8"#0 psi
2"8# psi
1"6$ psi
2"9$ psi
2"28 psi
1"$0 psi
%he difference in the dri)ing force and resistance to flow determines whether or not the flow will go into t L1"#$ psi
L3"23 psi
3"3$ psi
NR% %he example solution has that a 12 ft long tube will ha)e a positi)e difference" J thin5 this is due t solution, while J did not round in xcel, rather J referenced the cells that J needed" %o determine what tube difference, J created a rough .ood& plot using the other two Ke&nolds numbers and friction factors" J fit t that is what the .ood& plot loo5s li5e" J then extrapolated a friction factor based on the trendline, and fini positi)e dri)ing force with 13 ft long tubes" ;owe)er, note that this has uncertaint& associated with the ge resulting friction factor"
2ery 0ough 3oo4y 5lot !.!!!1(# r o t c a )
!.!!!1(
f)*+ -'.$%!%$"&$'"$$-!" ln)*+ / !.!!!##1'11 0 1
n o i t c i r )
!.!!!1('
!.!!!1(
!.!!!1'%
!.!!!1'#
!.!!!1'
!.!!!1'' 1!!!!
1"!!!!
1#!!!!
1$!!!!
1%!!!!
Re%nold(s #m$er
1&!!!!
'!!!!!
'1!!!!
Application of 19-*
+h )apor Fassume pure butane" er will be supplied b& saturated
%his will find the optimum heat exchanger t (se#-ente#ed data is in %!)* +E*. 40800 lb )apor produced+h
%ube (ata Jnner (iameter
0.62
Surface Area
0.1963
Jnternal %ube Area apor (ensit&
0.302 2.27
7i!uid iscosit& 7i!uid Specific Gra
0.1 0.43
An energ& balance should be calculated" (si
6sothermal 7oiling 5oint8
''+
9olumn 5ressure8
'9,
%he energ& needed to ma5e specified mass fl IO I
83$33 #9/6033
%o find how much steam is needed nthalp& of steam at gi)en conditions mO m H%
$0$ #9/6033 8//9 12/
%he maximum energ& flux is 12333 *tu+ft 2 AO
#9/6033
A
#29"$
ming a Ente# a len/t$ of te sc$ t$at t$e p#ess
16
N O re!uired surface area + Flen N 13/ 'sing !uation 19"26, the static pressure of )) O 1 + @ ) O
1+
2"26
))
3"883/
)7 O 1 + @7 O 1 +
20"$#2
)7 culation ratio"
3"3#6#
%he weight of the recirculated li!uid can be .7
10#233
ith this, the total )olume of the reboiler ou 7 O
10#233
7
) O
03$2
!%!!
)
16968
%otal )olume
283/0
%he specific )olume of the outlet can now b )o O
283/0 )o
+ 3"1169
Now that )o has been obtained, the static pre
P ance to flow" %o find
1"/9
Now the frictional resistance can be found" resistance to flow, the area of flow must be at O
13/
at
3"223
%he mass )elocit&, Gt, can be found b& di)id Gt O
238333
+
Gt
920#/1
Con)erting the )iscosit& units B
3"282
Con)erting the diameter of the pipe (
3"3/2
Now the Ke&nolds number can be found" Ke
Ke O
3"3/2 Ke
19666/
it$ t$e +enolds me# ao"e t$e f#i
f
0.000127
%he a)erage specific gra)it& can be found" sa)g O F
3"8# sa)g
D 3"2##
'sing *ernoullis e!uation the pressure drop
HP he reboiler"
2"66
%he total resistance to flow can be calculate %otal HP O
o the rounding done in the length pro)ided a positi)e hem to a log plot because J 5now shed the calculations" J got a eration of the .ood& plot and
2"66
D
%otal HP
8"#0
%he dri)ing force can be calculated O
10
2"9$
%he difference in the dri)ing force and resist difference O
2"9$ difference
L L1"#$
%he sample calculations, e!uations and spreadsheets presented herein were de hile e)er& effort has been made to present accurate and reliable technical inf %he Calculation Spreadsheets are pro)ided without warrant& of an& 5ind inclu Jn no e)ent will the GPA or GPSA and their members be liable for an& damage %hese calculation spreadsheets are pro)ided to pro)ide an QRperational le)el
be length for a )ertical thermos&phon that uses saturated steam at 12/ psi as an energ& source"
4 1 recirculation ratio
recirculation ration must be greater than or e!ual to 81
in ft2+ft in2 lb+ft# cp
/ t$e#modnamic data ente# t$e "ales elo.
°-
nthalp& of bottoms li!uid at specified %, P
241 *tu+lb
psi
nthalp& of bottoms )apor at specified %, P
338 *tu+lb
owrate of )apor
96
*tu+h
*tu+lb + lb+h steam -
+ 12333 ft2
$0$
#e diffe#ence is positi"e.
ft
7ength of %ube 12 ft
th of tube surface area of tube tubes
10 ft
183 tubes
10$ tubes
ft#+lb
3"883/ ft#+lb
3"883/ ft#+lb
ft#+lb
3"3#6# ft#+lb
3"3#6# ft#+lb
he reboiler leg can be found"
ound b& multipl&ing the )apor mass b& 8 Fthe minimum recirculation ratio" lb li!uid+hr
10#233 lb li!uid+hr
10#233 lb li!uid+hr
tlet can be found" !.!($(
ft#
03$2 ft#
03$2 ft#
ft#
16968 ft#
16968 ft#
ft#
283/0 ft#
283/0 ft#
3"883/
found using the total )olume and the total mass" 238333 ft#+lb
3"1169 ft#+lb
ssure of the reboiler leg can be found using !" 19"26"
3"1169 ft#+lb
psi
1"19 psi
3"99 psi
hen added to the static pressure, this will gi)e the total resistance to flow" %o find the frictional ound" %his is a t O Nt at + 188 !.!!'1
ft2
3"298 ft2
3"#/2 ft2
ing the mass flowrate b& the area of the tube" 3"223 lb+hr ft 2
09860# lb+hr ft 2
/6$909 lb+hr ft 2
fth+lb
3"282 fth+lb
3"282 fth+lb
ft
3"3/2 ft
3"3/2 ft
O ( Gt + B 920#/1
+
3"282 18$##1
12#039
ction facto# can e fond f#om a Mood ,lot. Ente# it elo.
ft2+in2
3"3#0
0.00013 ft2+in2
+
2 3"2##
can be found"
0.00014824 ft2+in2
3"2##
psi
1"28 psi
3"69 psi
b& adding the frictional resistance and static resistance" 1"/9 psi
3"8# psi
02"8
+
2"8# psi
1"6$ psi
2"28 psi
1"$0 psi
188 must be greater than the total resi
ance to flow determines whether or not the flow will go into the reboiler" 8"#0 psi
L3"23 psi
3"3$ psi
must be a positi)e )alue
eloped using examples published in the ngineering (ata *oo5 as published b& the Gas Processor Suppliers Ass ormation and calculation spreadsheets based on the GPSA ngineering (ata *oo5 sample calculations, the use of ing warranties of accurac& or reasonableness of factual or scientific assumptions, studies or conclusions, or merc s whatsoe)er Fincluding without limitation, those resulting from lost profits, lost data or business interruption ari of accurac& calculation based on rather broad assumptions Fincluding but not limited toT temperatures, pressures,
tance
ciation as a ser)i ciation ser)ice ce to the gas proce processing ssing indu industr& str&"" All infor information mation and calcu calculatio lation n formul formulae ae has been compi compiled led a such su ch inf infor ormat matio ion n is )ol )olun unta tar& r& and and the the GP GPA an and d GPSA GPSA do not not gua guara rant ntee ee the the acc accur urac ac& &, comp comple lete tene ness ss,, effi effica cac& c& or or ti hantabilit&,, fitness for a particular purpose or nonLinfringement of intellectual propert&" hantabilit& sing from the use, inabilit& inabilit& to , reference to or reliance on the information in thes Publication, Publication, whether based on omposition ompos itions, s, imperial imperial cur)e cur)es, s, site site conditi conditions ons etc and do do not repla replace ce detailed detailed and accura accurate te (esign (esign ngi ngineerin neering g ta
nd edited in cooperation with Gas Processors Association FGP FGPA" A" eliness of such information" Keference herein to an& specific commercial product, calculation method, process, arrant&, contract, tort or an& other legal theor& and whether or not ad)ised of the possibilit& of such damages" arrant&, ing int into o acc accoun ountt act actual ual pro proces cesss con condit dition ions, s, flu fluid id pro proper pertie ties, s, e!u e!uipm ipment ent con condit dition ion or fow fowlin ling g and act actual ual con contro troll se
or se ser) r)ic icee b& tr trad adeL eLna name me,, tr trad adem emar ar5, 5, an and d se ser) r)ic icee ma mar5 r5 ma manu nufa fact ctur urer er or ot othe herw rwis isee do does es no nott co cons nsti titu tute te or im impl pl& & en
tLpoint deadLband limitations"
orsement, recommendation or fa)oring b& the GPA and+
Example 19.17
-ind the oil circulation rate and the composition of the residue gas gi)en the following information" 6/ p from 133 mol of the rich gas stream" %he absorber will ha)e six theoretical plates, the a)erage temperatu and 1333 psig" Assume the lean oil is completel& stripped of rich gas components" %he feed composition Component C1
.ol M 93"0
C2
8"#
C#
#"2
iC8
3"/
nC8
1"3
C0
3"8
? )alues can be found from the e!uilibrium data in Chapter 2/, using the a)erage absorber conditions" Component C1
? #"2/3
C2
3"933
C#
3"#63
iC8
3"133
nC8
3"163
C0
3"3#/
-rom -igure 19"/1, A can be found using a as "6/ Fspecified efficienc& for propane absorption and nO0 A
3"$
!uation 19"29 can now be used" 73
29"0 mol+h
Now, A can be calculated for the remaining components" Component C1
A 3"391
C2
3"#29
C#
3"$33
iC8
2"903
nC8
1"681
C0
$"8/6
Now the absorption efficiencies can be determined for each component, using -igure 19"/1" Component C1
a 3"391
C2
3"#29
C#
3"6/
iC8
3"90
nC8
3"9$
C0
1
Now, the a )alue can be used to sol)e ! 19"#3 for the outlet composition of the lean gas" Component C1
E1 $2"#0
C2
2"$9
C#
3"$3
iC8
3"32
nC8
3"32
C0
3"33
Now the moles of each component in the rich oil, J, can be calculated b& stead& state material balance" Component C1
J $"28
C2
1"81
C#
2"83
iC8
3"8$
nC8
3"9$
C0
3"83
All the calculated properties are summariUed in a table below" Component C1
Mol &
A
Ea
B1
93"0
#"2/3
3"391
3"391
$2"#0
$"28
C2
8"#
3"933
3"#29
3"#29
2"$9
1"81
C#
#"2
3"#63
3"$33
3"6/
3"$3
2"83
iC8
3"/
3"133
2"903
3"90
3"32
3"8$
nC8
1"3
3"163
1"681
3"9$
3"32
3"9$
C0
3"8
3"3#/
$"8/6
1
3"33
3"83
%he sample calculations, e!uations and spreadsheets presented herein were de)eloped using examples pu hile e)er& effort has been made to present accurate and reliable technical information and calculation s %he Calculation Spreadsheets are pro)ided without warrant& of an& 5ind including warranties of accurac Jn no e)ent will the GPA or GPSA and their members be liable for an& damages whatsoe)er Fincluding w %hese calculation spreadsheets are pro)ided to pro)ide an QRperational le)el of accurac& calculation ba
Application of 19.17
rcent of the propane needs to be remo)ed re and pressure of the absorber are 138 is gi)en below"
%his will find the oil recirculation r completel& stripped" (se#-ente#ed data is in %!)* +E
Component C1
.ol M 90.6
C2
4.3
C#
3.2
iC8
0.
nC8
1.0
C0
0.4
"ales can e fond f#om t$e e;
Component C1
Fspecified tra&s"
? 3.20
C2
0.900
C#
0.370
iC8
0.210
nC8
0.170
C0
0.03
(sin/ Fi/#e 19.1 A can e fon
A
0.8
!uation 19"29 can now be used" 73
29"0
Now, A can be calculated for the re Component C1
A 3"391
C2
3"#29
C#
3"$33
iC8
1"813
nC8
1"681
C0
$"8/6
(sin/ Fi/#e 19.1 amd t$e ao"
Component C1
a 0.091
C2
0.329
C#
0.7
iC8
0.96
nC8
0.98
C0
1
Now, the a )alue can be used to so Component C1
E1 $2"#0
C2
2"$9
C#
3"$3
iC8
3"32
nC8
3"31
C0
3"33
Now the moles of each component i Component C1
J $"28
C2
1"81
C#
2"83
iC8
3"8$
nC8
3"99
C0
3"83
All the calculated properties are su Component C1
Mol &
93"0
C2
8"#
C#
#"2
iC8
3"/
nC8
1"3
C0
3"8
blished in the ngineering (ata *oo5 as published b& the Gas Processor Suppliers Association as a ser)i preadsheets based on the GPSA ngineering (ata *oo5 sample calculations, the use of such information or reasonableness of factual or scientific assumptions, studies or conclusions, or merchantabilit&, fitnes ithout limitation, those resulting from lost profits, lost data or business interruption arising from the use sed on rather broad assumptions Fincluding but not limited toT temperatures, pressures, compositions, im
te and the composition of the residue gas for an absorber, assuming the lean oil comes in . 7 M of propane remo)ed 6 theoretical plates 104 -, a)erage temperature 1000 psig, a)erage pressure ili#im data in C$apte# 2 sin/ t$e a"e#a/e aso#e# conditions. Ente# t$em elo.
sin/ t$e specified efficienc fo# p#opane aso#ption and t$e specified t#as.Ente# A elo.
mol+h aining components"
A "ales t$e aso#ption efficiencies can e dete#mined fo# eac$ component. Ente# t$em elo.
)e ! 19"#3 for the outlet composition of the lean gas"
n the rich oil, J, can be calculated b& stead& state material balance"
mariUed in a table below"
A
Ea
B1
#"2/3
3"391
3"391
$2"#0
$"28
3"933
3"#29
3"#29
2"$9
1"81
3"#63
3"$33
3"6/
3"$3
2"83
3"213
1"813
3"90
3"32
3"8$
3"163
1"681
3"9$/
3"31
3"99
3"3#/
$"8/6
1
3"33
3"83
ce to the gas processing industr&" All information and calculation formulae has been compiled and edited in coop is )oluntar& and the GPA and GPSA do not guarantee the accurac&, completeness, efficac& or timeliness of such i s for a particular purpose or nonLinfringement of intellectual propert&" , inabilit& to , reference to or reliance on the information in thes Publication, whether based on warrant&, contract, erial cur)es, site conditions etc and do not replace detailed and accurate (esign ngineering ta5ing into account
eration with Gas Processors Association FGPA" nformation" Keference herein to an& specific commercial product, calculation method, process, or ser)ice b& trad tort or an& other legal theor& and whether or not ad)ised of the possibilit& of such damages" actual process conditions, fluid properties, e!uipment condition or fowling and actual control setLpoint deadLban
eLname, trademar5, and ser)ice mar5 manufacturer or otherwise does not constitute or impl& endorsement, recom
limitations"
endation or fa)oring b& the GPA and+or GP
Example 19-8
(etermine the number of theoretical stages gi)en the following information" Sour water containing 2/33 ppmw n 1"/ ppmw" nough energ& is pro)ided b& the reboiler to produce "6/ lb steam per gallon feed" %he feed rate is 13 the tower operates at 21 psia" -irst, an o)erall material balance will be performed using the gi)en specifications" %he feed will be con)erted to mass flowrate" -eed
13 gpm 899$ lb+h
Now the mass of o)erhead steam can be calculted using the gi)en specification" R)erhead
8/3 lb+h
Now the o)erall stead& state material balance can be done, using the specifications gi)en" -eed Flb+h ;2S
12"/20
;2R
899$ /313"/20#
total
R)erhead Flb+h 12"/19
*ottoms Flb+h 3"336
8/3 8/8$ 802"/19 8/8$"330$
%he fraction of ; 2S stripped can be found b& di)iding the ; 2S in the o)erhead b& the ; 2S in the feed" -raction ;2S Stripped 3"999/ Jn order to estimate the top temperature, the fraction of water in the o)erhead and the partial pressure of water in the o)erhead need to be found" -raction of ; 2R in o)erhead 3"96# Partial pressure of ; 2R O fraction of ;2R pressure 23"8#2 psi 'sing the steam tables from Chapter 28, the temperature of the top was estimated to be 229 -" Now that the temperature is 5nown, the ? )alue for ; 2S can be obtained" ? O ; + P where ; is ;enr&s 7aw Con -rom -igure 19"/2
;, ;2S Fpsia
% F- 133 233
11333 1$233
#33
20333
At 229 -, the ;enr&s constant was interpolated and found to be 2"3/ 13 8" ?
960"19
Now the moles of )apor lea)ing the top tra& can be found using the masses from the material balance and the mol
2/"#6 mol
%he same can be done for the moles of li!uid lea)ing the bottom tra&" 7
2/2"06 mol
Now the stripping factor can be found" S% O ? + 7 S%
9$"311#2$
Now )arious )alues of s, the efficienc&, can be calculated assuming multiple )alues of m" m
s 1 2
3"9$993 3"99993
#
1"33333
Jn order to get the re!uired ; 2S remo)al fraction, 2 theoretical tra&s are needed"
%he sample calculations, e!uations and spreadsheets presented herein were de)eloped using examples published i hile e)er& effort has been made to present accurate and reliable technical information and calculation spreadshe
%he Calculation Spreadsheets are pro)ided without warrant& of an& 5ind including warranties of accurac& or reas Jn no e)ent will the GPA or GPSA and their members be liable for an& damages whatsoe)er Fincluding without li %hese calculation spreadsheets are pro)ided to pro)ide an QRperational le)el of accurac& calculation based on ra
eeds to be stripped to pm and the top of
Application of 19-8 s w ca cu ate t e num er o t eoret ca (se#-ente#ed data is in %!)* +E*.
-eed
10 gpm
899$ lb+h ,. lb steam pr
Now the mass of o)erhead steam can be calc R)erhead
8/3 lb+h
Now the o)erall stead& state material balance -eed Flb+h
R)erhead Flb+h
;2S
12"/20
12"/19
;2R
899$ /313"/20#
8/3 802"/19
total
%he fraction of ; 2S stripped can be found b& -raction ;2S Stripped O 3"999/ Jn order to estimate the top temperature, the of water in the o)erhead need to be found" -raction of ; 2R in o)erhead O 3"96# Partial pressure of ; 2R O 23"8#2 psi (sin/ t$e steam tales f#om C$
stant and P is the pressure" %top
229 °-
Now that the temperature is 5nown, the ? )al -rom -igure 19"/2 ;, ;2S Fpsia
% F- 133
11333
233 #33
1$233 20333
C$ec5 to ma5e s#e t$at top is it$in t$e
ecular weights of each component" :
?
23/6/
+
969"$
Now the moles of )apor lea)ing the top tra&
2/"#6 mol
%he same can be done for the moles of li!uid 7
2/2"06 mol
Now the stripping factor can be found" S% O S%
969"$
9$"#63
Now )arious )alues of s, the efficienc&, can m 1 2 # 8 /
s 3"9$993 3"99993 1"33333 1"33333 1"33333
/ompare t"e re0#ired fraction of '2 stri
n the ngineering (ata *oo5 as published b& the Gas Processor Suppliers Association as a ser)ice to the gas proc ets based on the GPSA ngineering (ata *oo5 sample calculations, the use of such information is )oluntar& and
nableness of factual or scientific assumptions, studies or conclusions, or merchantabilit&, fitness for a particular itation, those resulting from lost profits, lost data or business interruption arising from the use, inabilit& to , refe ther broad assumptions Fincluding but not limited toT temperatures, pressures, compositions, imperial cur)es, site
tages nee e to str p
;2S Concentration
2
rom sour water"
inlet outlet
200 ppmw
operating pressure
1. ppmw
o4uce4 per gallon fee4
lted using the gi)en specification"
can be done, using the specifications gi)en" *ottoms Flb+h 3"336 8/8$ 8/8$"330$ di)iding the ; 2S in the o)erhead b& the ; 2S in the feed" 12"/19 + must not exceed 1
12"/20
raction of water in the o)erhead and the partial pressure
8/3
+
802"/19
3"96#
21
must not exceed operating pressure pte# 24 estimate t$e tempe#at#e of t$e top and ente# it elo.
21 psia typically between '.$ to '&.$ psi
ue for ; 2S can be obtained"
slope intercept ;
6/ #833 23/6/ psia
an/e of t$e ao"e tale. f it is not t$e "ale is ext#apolated and ma not e acc#ate.
21
an be found using the masses from the material balance and the molecular weights of each component"
lea)ing the bottom tra&" tra&"
2/"#6
+
2/2"06
be calculated assuming multiple )alues of m"
Ke!uired fraction 3"999/
ped to t"e Es in t"e a$o3e ta$le to find "o! man% t"eoretical tra%s are needed.
essing industr& industr&"" All information and calculation formulae has been compiled and edited in cooperation with Gas he GP GPA A and GPSA do not guara guarantee ntee the accur accurac& ac&,, complet completeness eness,, efficac& efficac& or timeli timeliness ness of such infor information mation"" Kefe
urpose or nonLinfringement of intellectual propert& propert&"" rence to or relia reliance nce on the infor informatio mation n in thes Publi Publicatio cation, n, wheth whether er based on warran warrant& t&,, cont contract, ract, tort or an& other l cond co ndit itio ions ns etc etc and and do not not rep repla lace ce det detai aile led d and and accu accura rate te (es (esig ign n ngi ngine neer erin ing g ta5i ta5ing ng int into o acco accoun untt actu actual al pro proce cess ss co co
rocessors Association FGPA" rence herein to an& specific commercial product, calculation method, process, or ser)ice b& tradeLname, trademar
egal theor& and whether or not ad)ised of the possibilit& of such damages" ditions, fluid properties, e!uipment condition or fowling and actual control setLpoint deadLband limitations"
, and ser)ice mar5 manufacturer or otherwise does not constitute or impl& endorsement, recommendation or fa)o
ring b& the GPA and+o
LIMITS
*ampel 1&-' ;ptimum operating reflu* ratio are 1.' to 1.( times the minimum reflu* ratio *ample 1&-(
1!-1" psig '!!-'(! oA '!-'"! oA 1!!!-'!!! 7tuCgal !."-'.! ppmmw