final boris sova hy sys

8/10/2019 Final Boris Sova Hy Sys

1/17

FAO: Dr Antonia Borissova

Mariam Hussain

200603585

PEME2030

HYSYS 2 - Mass & Enr!" Ba#an$s %on-

ra$tiv S"stms'


2/17

Pro(#m statmnt

100 kmol/h of a mixture consisting of the following three components and their

respective mole fractions:

n-Hexane 0.3

n-Heptane 0.4

n-ctane 0.3

is fed at a temperature of !0 "# into the first of two separators operating at apressure of $00 k%a a&solute and 'emperature 1$3 "#. 'he li(uid from the firstseparator is then fed to the second separator operating at the same pressure) &ut atemperature of 1$* "#. + fraction 0., of the li(uid from the second separator isreccled to the first separator.

S#$tion o) *uation o) stat

'here are a few reasons the e(uation of state setting was used. 'he

setting uses the oave-edlich-wong method to determine the properties of the

components of the streams) it is suita&le &ecause all chemicals present are non-

polar and this e(uation is onl valid for non-polar chemicals. 'his e(uation of state

has advantages over other e(uations of state. or example the &asic edlich-wong

e(uation can &e used) however) when the chemicals involved are non-polar or

complex the results are ver inaccurate. 2n the separator processes designed) the

chemicals were all non-polar and (uite complex) making this e(uation rather

unsuita&le.

'he oave edlich-wong e(uation is shown in e(uation 1 &elow:

)(

)(

bVV

Ta

bV

RTp

+

= 1

p5pressure) k%a) a'5 a parameter which is the function of temperature)

it6s e(ual to

25.0

22

114274.0

+

c

c

c

T

Tm

p

TR

7ariam Hussain $00!03*8*

$


3/17

where m5 2176.07.148.0 + and 5 acentric factor. 95volume in m3)

c

c

p

RTb 08664.0= where is the universal gas constant 2#H+) $001.

'5temperature) elvins

Ba$+!roun,

eparation of chemicals highl depends on the phsical and chemical properties of

the chemicals; separation processes exploit these properties to allow efficient

separation) such as differences in &oiling points) viscosit and densit.

'he differences is &oiling points of different chemicals is used to separate chemicals

in industrial processes such as fractional distillation of crude oil) in the

pharmaceutical industr various isomers of pharmaceuticals) and in the purification

of polmers where lower &oiling point monomers are removed. #hemicals with lower

&oiling points have a higher volatilit. 2n industrial applications) temperatures of

evaporators are carefull controlled to evaporate and separate various chemicals.

=#H=72#+?#) $011.

+spen H@@Ais used in industr to design process plants. 2t is often used in the

petroleum industr &ecause it is pre-set with various crude oil components and the

relevant properties of these components such as cloud point. 2t simplifies the designs

of multi-component) multi-unit operations. 2t contains multiple operations used in the

petroleum industr such as separators and reactors +%=B'=#H) $01$a.

+spen H@@ has the advantage of accuratel stimulating real life stream flows)

stimulating expected &ehaviour of these streams +%=B'=#H) $01$&.

om.utr simu#ation

irstl) +spen H@@ was opened) then a new case was opened up and the

fluid package was selected and three components was added) n-heptane) n-hexane

and n-octane. 'hen) the simulation environment was added.


3


4/17

$ process flow diagrams were designed on +spen H@@ software. Coth process

flow diagrams involved mixers and separators. ue to this it was apparent &oth

sstems would have mass and energ &alances. 'o define an stream) $ properties

must &e known. +s the input temperature and compositions of the 3 chemicals were

know aswell as the input pressure and the molar &asis was set asinlet5100kmol/hour) when all the unit operations were all added and heat was input

as re(uired) H@@ automaticall using the e(uation calculated the properties

of all streams.

or the 1 separator process) the process flow diagram was set up as shown in figure

1 &elow:

Fi!ur /: .ro$ss )#o ,ia!ram )or / s.arator s"stm

'he inlet and inlet feed had the specified properties:

3.0

4.0

3.0

188

167

146

=

=

=

HC

HC

HC

x

x

x

'he inlet pressure was $00 k%a and the molar flow was set as 100k7ol/hr) these

were entered in the Dwork&ook6. =nerg was also added as an inlet & dou&le clicking

on the separator as the separator was set to operate at 1$3o# and the energ input

was automaticall calculated. 'his separation occurs due to the differing &oiling

points of the three components to &e separated. Hexane has a &oiling point of !Eo#)

heptane has a &oiling point of E8o# and octane has a &oiling point of 1$*o#

=?7H>') $003.


4


5/17

ollowing this) a $ separator sstem was designed in the +spen H@@ software. 2t

was designed as shown in figure $ &elow:

Fi!ur 2: 2 s.arator s"stm PFD

'he inlet flows were same as for separator 1) the pressure of feed is $00k%a) heat is

input into separator 1 to allow it to reach a temperature of 1$3o#. 'here are $

product streams from the first separator) a vapour stream and a li(uid stream. 'he

li(uid stream is fed into another separator and the second separator operates at a

temperature of 1$*o# as heat is further added into the second separator to maintain

this temperature. 'here are $ product streams from the second separator; a li(uid

product and vapour product stream. 'he li(uid product stream is split into $ streams

where ,0F of the li(uid product is a reccle stream and is fed into the separator. 'o


*


6/17

ensure the ratio of the li(uid product to reccle is ,:3) a Dtee6 is added and the li(uid

stream which is fed into the tee parameters are set to make the flow ratio of the

output 0., for the li(uid product and 0.3 for the reccle.

1su#ts

or 1 separator sstem:

Fi!ur 3: .ro.rtis o) a## in#t an, out#t strams

igure 3 a&ove shows the properties of the inlet and outlet streams. 'he text in &lue

was entered and the text in &lack was calculated & the software.


!


7/17

Fi!ur : $om.ositions o) t / s.arator s"stm

igure 4 a&ove shows the compositions of the input and output streams of the 1

separator sstem.


,


8/17

Fi!ur 5: at in.ut into t s.arator

igure * shows the heat input into the separator.


8


9/17

eparator $ results

igure ! &elow shows the properties of all the streams of the $ separator sstem.

Fi!ur 6: .ro.rtis o) a## strams o) t 2 s.arator s"stm


E


10/17

igure , &elow shows the commpositions of all the components of the $ separator

sstem.

Fi!ur 4: $om.onnts $om.ositions o) a## strams in t 2 s.arator s"stm


10


11/17

Fi!ur 8: at in.uts into (ot s.arators

igure 8 shows the $ individual heat inputs of &oth separators of the $ separator

sstem; heat 1 is the heat input into the first separator and heat $ is the heat input

into the second separator.


11


12/17

Dis$ussion

Coth the 1 separator and $ separator sstems are a&le to effectivel separate thesemixtures; however there are advantages and disadvantages of &oth sstems.

Temperature, oC

Vapourfraction ofhexane

liquidfractionofhexane

Vapourproductmolarow,kMol/hr

liquidproductmolarow,kMol/hr

VapourfractionofOctane

liquidfraction ofOctane

molar owof hexanein vapour,kMol/hr i

115 !5"#5 !" 1 !1#5$ !"

11% !5#%1 !#&%1 1!#'' &(!%" !1#(1 !"##

!''%"('


1$


13/17

11& !$("& !#'1' 1%!#& (#!%1 !1$(5 !""1%

(!"'''"1

1#1 !$$## !##&" ""!#1 ''!%& !1%# !"'"%

1$!'(5$'#

1#" !$#$ !#" $&!"1 5!'& !1&(( !"&(

5

1&!($#"$

$1#5 !"'51 !1%$' '5!(" "$!1% !##&$ !$"' #$!"$5""

1#% !""" !151( ("!1 1'!&& !#'"& !$%'1

#%!$1(#"

1#& !" !1"" 1 !" !5155

"

'he $ separator sstem has higher initial costs due to the fact it has and extra

separator and a Dtee flow splitter6 unit which ultimatel makes set-up of the

e(uipment more costl. urthermore) the total energ input to the $ separator sstem

is much greater than the total energ input into the one separator sstem) meaning

the running costs for a one separator sstem is much greater than the one separator

sstem. 7oreover) the $ separator sstem has the advantage that it contains a

reccle stream which allows the overall separation of hexane in the inlet feed to &e

maximised &ecause some of the li(uid outlet containing hexane is again fed into the

first reactor as the reccle stream.

+ sensitivit analsis was carried out on the 1 separator sstem. irstl the effect of

changing temperature of the inlet feed stream on the compositions of the n-hexane

component and n-octane component was recorded for the separator in the 1

separator sstem and is shown in ta&le 1 &elow:

a(# /: A ta(# soin! $om.ositions o) an in t va.our an, #i*ui,out#t strams o) t / s.arator s"stm as ## as t mo#ar )#o o) #i*ui, an,va.our strams an, o it7s a))$t, (" tm.ratur

'his shows that as the temperature increases the vapour fraction of hexane in the

vapour stream decreases and the li(uid fraction of octane in the li(uid stream also

decreases meaning separation increases) however the molar flow of the vapour

stream also decreases. 'o maximise the hexane molar vapour fraction the

temperature needs to &e decreased. However) if the temperature is decreased &elow

11*o

#) it no longer affects the molar fraction of the hexane molar vapour fraction.


13


14/17

=ven though the vapour fraction of the vapour is at its maximum) there is no vapour

stream) so a compromise needs to &e made &etween the vapour fraction of hexane

and the molar flow of the vapour product.

However) if ou consider the hexane molar flow of the outlet streams of the

separator) it can help the decision of selecting the temperature. 'his graph is shown

in figure E:

Fi!ur : A !ra. soin! t ))$t o) t tm.ratur o) in#t stram on mo#ar)#o o) an in #i*ui, an, va.our strams


14


15/17

'his graph shows that the molar flow of hexane in the vapour is maximum at

temperatures of 1$8o# and a&ove a plateau is reached at 1$Eo#. o) at higher

temperatures rate of hexane separated is increased.

ollowing this) a sensitivit analsis was carried out for the effects on changing the

pressure of the inlet and hence outlet streams for the one separator sstem:

)re**ur

e, k)a

Vapour

fraction ofhexane

liquid

fraction ofhexane

Vapour

productmolarow,kMol/hr

liquid

productmolarow,kMol/hr

Vapour

fraction ofOctane

liquid

fraction ofOctane

molar ow

of hexane invapour,kMol/hr

# !$#$ !#" $&!"1 5!'& !1&(( !"&(5

1&!($#"$$

#1 !$'1 !#"1 $%!%# 5#!#( !1&'1 !"&$(

1&!"%&

## !$&( !#5& $'!1$ 5"!(' !1&"5 !"&1#

1(!&(1%#

#" !$1"5 !#(( $$!5' 55!$$ !1&& !#(%%

1(!$#55'

a(# 2: A ta(# soin! $om.ositions o) an in t va.our an, #i*ui,out#t strams o) t / s.arator s"stm as ## as t mo#ar )#o o) #i*ui, an,va.our strams

'his shows that as pressure increases) the vapour fraction of hexane increases) and

the molar fraction of octane in the li(uid outlet increases meaning separation

increases) however the molar flow of the vapour product decreases. +t $$! k%a

pressure) the vapour fraction of hexane reaches its maximum) so separation is

maximised however) at this pressure) the molar flow is Gero so a compromise is

needed &etween maximum separation and molar flow rate of vapour.

However) if ou consider the hexane molar flow of the outlet streams of the

separator) it can help the decision of selecting the pressure. 'his graph is shown in

figure 10:


1*


16/17

Fi!ur /0:A !ra. soin! t ))$t o) .rssur o) in#t on mo#ar )#o o)an in va.our an, #i*ui, strams

o) as pressure increases) molar flow rate of hexane in the vapor outlet stream

decreases and the maximum molar flow rate is at a pressure of 1,4 k%a and if the

pressure is decreased &elow this point) it has no effect on the molar flow rate of

hexane in the vapour stream.


1!


17/17

1EFE1EES

+%=B'=#H) $01$a)ASPEN HYSYS Petroleum refining,onlineI) +vaila&le from:

http://www.aspentech.com/products/aspen-refss.aspx +ccessed 1$/11/$01$I

+%=B'=#H) $01$&, ASPEN HYSYS Dynamics) onlineI) +vaila&le from:

http://www.aspentech.com/products/aspen-hss-dnamics.aspx +ccessed

1$/11/$01$I

=?7H>') $003) BOILING POINTS AND ST!"T!ES O# HYDO"ABONS)

onlineI) +ccessed 1$/11/$01$I +vaila&le from:

http://www.elmhurst.edu/Jchm/vchem&ook/*01hc&oilingpts.html +ccessed

1$/11/$01$I

%=>=#H=72#+?#) $011) istillation #apa&ilities ) onlineI) +vaila&le from:

http://www.presschem.com/distillation.htm+ccessed 1$/11/$01$I

2#H+) $001) "$a%ters &' e(uations of state) pdfI) onlineI +vaila&le from:

http://www.swin&urne.edu.au/ict/research/cms/documents/disertations/sw#hap3.pdf

+ccessed 1$/11/$01$I


1,
http://www.presschem.com/distillation.htmhttp://www.presschem.com/distillation.htm

final boris sova hy sys

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