CHBE Report

7/26/2019 CHBE Report

1/16

Temporary Emergency CoolingSystem

for

Polystyrene Reactor R205

By:

Naveen Krishnan

oan or!anov

"!am #$i

%niversity of llinois at %r&ana Champaign

'epartment of Chemical Engineering

C(BE )2* +ro$p )

"pril 2,- 20*5

Ta&le of Contents:

. E/ec$tive S$mmary

2


2/16

. Bacgro$n! 2

. "nalysis ,

Schematic ,

1ater an! (eat Transfer ,

1ater Tans ,Piping an! Pipe Rac )

alves an! El&o3s )

4echanical Energy Balance an! Simplifications )

P$mping an! "fter3ar!s 5

. Recommen!ation 5

. "ppen!i/

E6$ations

Calc$lations 7

mages 8

So$rces *)

I. Executive Summary:

This pro9ect entails !esigning an emergency cooling system for R205- a polymeri;ation

reactor. "fter revie3ing the schematic- cost s$pplement- an! heat transfer information- it 3as

!etermine! to $se sche!$le )0 3el!e! car&on steel pipe of )in !iameter. The plant sho$l! &$il!

t3o ,0-000gallon 3ater tans 3ith close pro/imity to R205


3/16

the tans 3o$l! &e !esignate! as the cool 3ater tan- fille! 3ith 20C 3ater- an! then p$mpe!

3ith a single centrif$gal p$mp thro$gh a cooling 9acet on R205. The 3armer 3ater 3ill e/it the

cooling 9acet at )0C an! enter the !esignate! e/it tan. The e/it tan 3o$l! initially &e empty

an! it 3o$l! receive 3ater that e/its from the cooling 9acet. The 3ater in the e/it tan- in case

any contaminants mi/e! into it- can &e taen to a 3ater treatment plant via 3ater tan tr$c. "

tr$c is $se! &eca$se it is cheaper than installing pipes an! piping racs to move the 3ater tothe treatment plant. This plan 3ill &e the most costeffective 3ay to !esign an optim$m

emergency cooling system for R205 3ith a total cost of @**5-000.

II. Background:

The &ac!rop for the pro&lem statement involves the cooling of a polymeri;ation reactor.

The present system- a 3ater to3er 3hich $ses a press$re hea! to force 3ater into a cooling

9acet- 3ill &e $n!ergoing maintenance for fo$r months an! the plant 3ill re6$ire a &ac$p

temporary cooling system in case there is an emergency sh$t!o3n. The sh$t!o3n 3ill nee!

cooling as the reactor 3ill still have reactions for another thirty min$tes after la$nching sh$t!o3n

proce!$res. The cooling po3er $s$ally re6$ire! is given to &e *2.544Bt$Ahr an! sho$l! !rop

!o3n from there !$e to slo3ing reactions !$ring sh$t!o3n- &$t a 3orst case scenario can &e

ass$me! 3here there 3ill &e a constant nee! for a removal of that energy rate. (eat transfer

e6$ations 3ill &e $se! to calc$late a mass flo3 rate of a coolant in or!er to meet that cooling

energy. " given contact area of *5)0ft2 3as also given 3hich 3ill help calc$late a &etter heat

transfer coefficient an! temperat$re change for the coolant.

Piping material- length- an! !iameter 3ill &e !etermine! $sing a mechanical energy

&alance- an! !epen!ing on the system- pipe rac 3ill &e nee!e! to hoist piping in non race!

areas at @2200A*00ft. ?l! piping an! valve pricing !ata 3as provi!e! per !iameter of pipe an!

material. " factor of ).8 3ill &e m$ltiplie! &y the pipe costs !$e to inflation an! installation costs.

Costs of vario$s p$mps 3ere given 3ith a logarithmic f$nction &ase! off material- press$re

range- an! shaft po3er provi!e!. Costs per !iameter an! material of piping 3ill &e $se! to!etermine the &est !iameter piping for the ne3 system as $sing $niform !iameter 3ill &e easier

to p$rchase an! install.

Assumptions:

Stea!y State the moment the system is activate! The maintenance 3ill &e !one in the s$mmertime 3ith am&ient average

temperat$re of 25C 1ater !ensity is constant 88DgAm, 1ater viscosity is constant .00*gAms

III. Analysis:

Schematic:

The original !esign . The system 3ill have 2 ne3 3ater tans constr$cte! an! 3ill $se 3ater

as the coolant &eca$se of its high heat capacity


4/16

&e nee!e! to s$pport the pipes to the ne3 3ater tans. The 3ater tans are locate! a&o$t *00ft

east of R205- the closest location 3ith 6$ic access to the pipe racs an!

also alongsi!e the roa!s. The col! 3ater tan 3ill initially &e the only one fille! 3ith 3ater an! at

the &ottom- there 3ill &e a p$mp to p$mp it $p to the cooling 9acet. "ss$mptions that the inlet

an! o$tlet of the cooling 9acet 3ere the same height- no loss 3or nor press$re !rop- an! that

the cooling 9acet is 3ell mi/e! 3ere ma!e to simplify the energy &alance an! to ignore any$neven !istri&$tion of heat. The 3ater- leaving the 9acet 3armer than it 3ent in- 3ill then have

eno$gh energy to travel an! fill the secon! 3ater tan.

Water and Heat Transfer:

The 3ater 3ill &e store! in a 3ater tan an! &e at 20C. "ltho$gh the am&ient air 3ill &e

ass$me! to &e 25C- 3ater reg$lates its stea!y state am&ient temperat$re to &e cooler !$e to

its high heat capacity. Reactor R205 re6$ires *2.544Bt$Ahr to &e maintaine! at itFs

temperat$re of ,)0GA*7*.*C. The first ass$mption is that the cooling 3ater 3ill &e p$mpe! to

the 9acet an! p$mpe! o$t 3ith an overall change in temperat$re of 20C an! &e at )0C. t

sho$l! not e/cee! )0C &eca$se of fo$ling affects. 1ith that given change in temperat$re- a

no3n heat transfer rate- an! a given constant heat capacity coefficient to &e *D0.81Am2AK 3hich is compara&le to

real transfer val$es &et3een *50*200 for a heat e/changer 3ith li6$i! interior an! e/terior


5/16

the pipes 3ill &e o$t!oors an! that car&on steel operates at a press$re higher than PC is

!etaile! to operate atI sche!$le D0 PC is rate! to 0psig or a&o$t ) &ars 3hereas sche!$le )0

car&on steel is rate! to &e in the *000,000psig or 70200 &ars !epen!ing on !iameter

.

!echanical Energ" #alance and Simplifications:

t is ass$me! the press$re at the top of the initial col! 3ater tan an! the press$re o$tlet

of the pipe into the hol!ing e/it tan are * atm . Kinetic energy an!

potential energy can &e ignore! &eca$se the length of piping of more than 2000ft or 00m 3ill

ca$se the loss 3or term to &e significantly &igger. The shaft 3or of the p$mp is e6$ivalent to

the change in press$re times the 3aterFs vol$me flo3 rate. "lso- the loss 3or an! press$re

!rop in the cooling 9acet is ignore!- an! th$s- the &alance is simplifie! . " pipe !iameter of )in 3as !etermine! to

&e the &est. 'iameters 2 an! , 3ere also lo3 costs- &$t the po3er ratings 3ere too high for any

p$mp. P$mps 3ere compare! an! the most cost efficient p$mp 3as the centrif$gal p$mp.

"ltho$gh it might have $neven flo3 rates compare! to positive !isplacement- this system

alrea!y overco$nts the flo3 rate &y ass$ming it nee!s a constant flo3 to cool the constant

*2.544Bt$Ahr- an! the centrif$gal p$mp is a lot cheaper 3ith its lo3er coefficients


6/16

acco$nt for shipping- ta/- 3ages- an! gas- it comes o$t to &e @,500A3ee 3hich sho$l! &e

eno$gh to transport all the 3ater to the 3ater treatment &$il!ing . Bac$p generators in the case of a po3er o$tage

Renting a tr$c for the 3ee the system 3as $se! 3o$l! transport the 3ater to the 3ater

treatment &$il!ing- an! 3o$l! &e m$ch cheaper than &$il!ing pipes- racs- an! a stronger

p$mp.

Total Costs

%tem &ost '()

System

Piping 0-505

Centrif$gal P$mp 2-D)D

Pipe Rac *-*00

1ater tans *2-000

Total *00-)5,

er use

Electricity D.*

Tr$c rental ,-500

Total ,-50D.*

Total Cost !Assuming "use#mo $or %mo& **)-)D5.)

V. A''endix:

E*uations:

*> (eat transfer *: q=mC p T 1here 6 is the heat transfer rate- m is massflo3 rate- Cp is heat capacity- an! T is the change in temperat$re.

2> (eat Transfer 2: q=UA Tlm 1here % is the heat transfer coefficient- " is the

contact area- an! Tlm is the log mean temperat$re change given

( T2 T1)/ ln( T2/ T1) .

5


7/16

,> 4echanical Energy Balance: P/+g z+ u2/2+Ws/m+ lw=0 1here l3

is loss 3or of the pipes an! e6$als 2 f(Leq/D)U b2 an! %& is &$l velocity an! ' is !iameter.

)> Simplifie! Energy Balance: P=(lw)5> Reynol!s N$m&er L UbD /( /) 1here is the fl$i! viscosity

&alculations:

*> Total massAvol$me flo3 rate:

6 L *2.544Bt$Ah L ,,,DD.) As

Cp L ).*D AgC

T L 20C

q=mC p T LM m L ),.D20gAs LM LM ol$me flo3 rate L **.galAs L 20D27galA,0min

2> (eat Transfer Coefficient:

6 L ,,,DD.) As" L *5)0 ft2 L *),.7 m2

'ifference in o$tlet temperat$res: T2 L *7*.****C )0C L *,*.****C L

*,*.****K

'ifference in inlet temperat$res: T1 L *7*.****C 20C L *5*.****C L *5*.****K

Tlm L ( T2 T1)/ ln( T2/ T1) L *)0.D7Kq=UA Tlm LM %L*D0.81Am2AK

,> Pipes CostA'iameter

Pipes L2*702*7'

'iameter

'iameter

E6#ength E6#ength

Car&on Steel 1el!e!

@AmeterA'iameter

Total Cost !(ased

on )e*&

Total Cost + in$lation#install

!,%.-&* 0.025) 2200.7 70.7,2 2. *7),.8D),2 D5)5.52,*D

2 0.050D 22*7.,,,,,, 75.D),2 )055.0582 *8D8.7800D

, 0.072 22,) D0.82,2 *0 D08.2,2 ,,,5.2,D

) 0.*0* 2250.7 D.00,2 *D *2,)D.057 0505.)D22)

5 0.*27 227.,,,,,, 8*.0D,2 2* *)5*2.7)72 7***2.)*2D

0.*52) 22D) 8.*,2 ,0 20DD).D8 *02,,5.880)

7 0.*77D 2,00.7 70*.2),2 )0 2D0)8.72D *,7)),.72

D 0.20,2 2,*7.,,,,,, 70.,2,2 50 ,5,*.* *7,0)8.*D)

)> Pipe #oss 1orPipe #oss 1or ol$me

'iameter eA' Reynol!Js L 'H%&HpA$ G B$l elocityO%&

* 0.002 2*82085.2 0.005 D.)7582

2 0.00* *080)7.D* 0.005 2*.*D8D

, 0.0007 7,08D.5) 0.00)5 8.0D),

) 0.0005 5)D02,.805 0.00)) 5.)0)7)5


8/16

5 0.000) ),D)*8.*2) 0.00), ,.)580,7

0.000,,,,,,,,,, ,5,)8.27 0.00)2 2.)02*0

7 0.0002D57*)2D57 ,*,*5.5*72 0.00)2 *.7)D*)

D 0.00025 27)0**.8525 0.00)2 *.,5**D

5> 4echanical Energy Balance

EB E6$ation )

Shaft

1or L

Press$re

H ol$me

Rate

'iameter

'iameter

P$mp

Press$re

Shaft

1or 1hA,0min

1hA,0min

70 efficiency

* 0.025) 2207,8)0 2207,.8) ,200D.57*D 87225*5.02 )D,*.2578 80D7.5**2D

2 0.050D 205D,7).*

20.5D,7)

* D88D.)),*8 27*827,.D58 *,58.,8) *8)2.,,D)D

, 0.072 7)*250.57

7).*25057

*07).D*,)5) ,2)D0*.2*,* *2.)00078 2,2.000DD)

) 0.*0* *7,))0.08D

*7.,))008

D 25*.522D*)2 700D.)58D* ,D.00)2,02* 5).28*757))

5 0.*27 5*20.0,*2

5.*200,*

2 D*.,D270)52 2)58,.28205 *2.28)*2 *7.5,7,2

0.*52) 22,)**.5282

2.2,)**528

2 ,2.,8)7*7) 87D8.)),D8 ).D8)72,2,, .882)*72

7 0.*77D *05)25.7,57

*.05)257,5

7 *5.2D7,*D )*8.5))DDD 2.,08772), ,.2887)8)7

D 0.20,2 55)D.,)7,

0.55)D,)

7, D.080520, 2),D.)**D77 *.2*82058)D *.7)*7227D,

> P$mp Cost %sing mage 7

um'

Cost

' Bar

Recip

Gp

Pos 'is

Gp

Centrif

Gp 1 Recip Cp

Cost

Total Pos 'is Cp

Cost

Total Centrif Cp

Cost

Total

*

2207,.8

) * * *

8722.5*5

02

,005,)58,.

D

2**8D50

D** 5,0*0D7D.75

,)D88*D

*8.2

*08,2.050

D*

7)5)0.*D

D)

2

20.5D,7

)* * * *

27*8.27,D

58 2)78005.DD

*7)D58*

5.D7 ),,)50.,0*8

2D5,57

.7*7

5D).*,7

5

,D70.5,

DD

,

7).*250

57

*.55,)

85*D2

*.55,)85

*D2

2.*D0)

,*702

,2).D0*2*

,*

27*087.5,2

D

2)7)

.08 52D78.8,0)7

))))5.

0*8

)*7.785*

72

)5D.0

807

)*7.,))0

08D*.*,)*,,77D

*.*,)*,,77D

*.2,8D8)*,

7.00D)58D*

7D5.*5DD

58))85.)52 *7,7.*775

*22002.)70*

,502.D2D02

2D)7.)52

5

5.*200

,*2 * * *

2).58,282

05

,508,.D0**

,

2)75,7.

,5 D770.)D)*

577,8.5

0,25

,**5.2D8)*

)

2*2)*.0

0D7

2.2,)**5

282 * * *

8.7D8)),

D8

2008.,D),

5

*)*5*.

)08) 5)8.)55

,7*82.

,*82

2D.D2D2

*2

*85)7.)

D*7

7

*.05)257

,57 * * *

).*85))D

DD

*,00.D55D

8

858,).8

8707 )28.08DDD

2D*05.*

D5)8

270*.58

D8

*D)20.,

)52

D 0.55)D * * * 2.),D)**D *02,D.7,8 722*8.8 ,555.5**5 2,)07. 25D,.7DD *7*7.)2

7


9/16

,)7, 77 8)5 D*,D 5 D0*

%mages+&harts:

mage *: ?riginal Plant #ayo$t

D


10/16

mage 2: Recommen!e! System *

8


11/16

mage ,: Recommen!e! System 2 Ohot 3ater tan L e/it tan

mage ): Pipe Gittings #e6A'

*0


12/16

mage 5: Griction Gactor Chart

**


13/16

mage : Pipe Pricing

*2


14/16

mage 7: E6$ations an! Charts for total P$mp Price

*,


15/16

mage D: Cost of Piping an! P$mp per 'iameter

Sources:

*> 1ater 'ata:

http:AA333.engineeringtool&o/.comA3aterthermalproperties!Q*2.html

2> Realistic (eat Transfer Coefficient: http:AA333.engineeringtool&o/.comAheattransfercoefficientse/changers!Q)50.html

,> 1ater Tan:

http:AA333.ali&a&a.comApro!$ct!etailATop6$alitypop$lar20000gallon

3aterQ0*78*)D2),.html

)> Car&on Steel Piping Press$re Rating:

http:AA333.engineeringtool&o/.comAa*0car&onsteelpipes!Q,70.html

5> P$mp Priority:

*)
http://www.engineeringtoolbox.com/water-thermal-properties-d_162.htmlhttp://www.engineeringtoolbox.com/heat-transfer-coefficients-exchangers-d_450.htmlhttp://www.engineeringtoolbox.com/heat-transfer-coefficients-exchangers-d_450.htmlhttp://www.alibaba.com/product-detail/Top-quality-popular-20000-gallon-water_60179148243.htmlhttp://www.alibaba.com/product-detail/Top-quality-popular-20000-gallon-water_60179148243.htmlhttp://www.engineeringtoolbox.com/a106-carbon-steel-pipes-d_370.htmlhttp://www.engineeringtoolbox.com/heat-transfer-coefficients-exchangers-d_450.htmlhttp://www.engineeringtoolbox.com/heat-transfer-coefficients-exchangers-d_450.htmlhttp://www.alibaba.com/product-detail/Top-quality-popular-20000-gallon-water_60179148243.htmlhttp://www.alibaba.com/product-detail/Top-quality-popular-20000-gallon-water_60179148243.htmlhttp://www.engineeringtoolbox.com/a106-carbon-steel-pipes-d_370.htmlhttp://www.engineeringtoolbox.com/water-thermal-properties-d_162.html


16/16

http:AA333.&lacmersmartenergy.comAcomparative!ataAcentrif$galp$mpsvspositive

!isplacementp$mps.html

> Tr$c Rental:

http:AA333.machinerytra!er.comAlistings!etailA!etail.asp/?('L*050,),,

7> Electricity Cost:

http:AA333.eia.govAelectricityAmonthlyAepmQta&leQgrapher.cfmtLepmtQ5QQa

*5
http://www.blackmersmartenergy.com/comparativedata/centrifugal-pumps-vs-positive-displacement-pumps.htmlhttp://www.blackmersmartenergy.com/comparativedata/centrifugal-pumps-vs-positive-displacement-pumps.htmlhttp://www.machinerytrader.com/listingsdetail/detail.aspx?OHID=10503433http://www.eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_5_6_ahttp://www.blackmersmartenergy.com/comparativedata/centrifugal-pumps-vs-positive-displacement-pumps.htmlhttp://www.blackmersmartenergy.com/comparativedata/centrifugal-pumps-vs-positive-displacement-pumps.htmlhttp://www.machinerytrader.com/listingsdetail/detail.aspx?OHID=10503433http://www.eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_5_6_a

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