PSV Sizing Psv-402 Update Pset

 

Project Unit 135355

Revision Date Originator  Checked by Approved by

CALCULATION NOTE PRESSURE RELIEF SIZING 1 2

SUMMARY AND CONCLUSION PSV-402

3 4

1. PSV Size

5 6

Relief Load

Rated Flow Req. orifice Back pres.

Scenario 7 8

Vapour release

(kg/h)

MMSCFD

mm2

kPag

33851

16.93

601.1

178.7

10 11 12

PSV or orifice si size is is d deesign gnaated as as ""3 3J4"

13 14 15

2. PSV Inlet and Outlet Line Size

16

Line

17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 49 50

Material

Size (in)

Flange Rating

Inlet line to PSV

CS

4

#300

Outlet line from PSV

CS

6

#150

Code Discipline

Type

01

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Page R  e   v  .

 

Project Unit 135355

Code

PRESSURE RELIEF SIZING

Rev. 00

Discipline 01

Type REP

009

0

1

2

Revision Date Originator  Checked by Approved by

CALCULATION NOTE

Serial Number

Page R  e   v  .

1 2 3

CALCULATION OBJECTIVE i. To identify the orifice size of PSV-402 in fire case

4

ii.

To identify the PSV inlet and outlet line size

5 6

CALCULATION METHOD and STANDARD

7

i.

AP APII ST STD D 521, 521, A Add dden endu dum m May May 20 2008 08 "Gu "Guid idee for for Pres Pressu sure re Reli Reliev evin ing g an and d Depr Depres essu suri ring ng S Sys yste tem" m"

8

ii. ii.

AP APII S STD TD 52 526, 6, Er Erra rata ta Ma May y 200 2009 9 "Fl "Flan ange ged d Ste Steel el Pres Pressu sure re Re Reli lief ef Va Valv lve" e"

9

iii.

Line Sizing Philisophy

10

ASSUMPTION AND BASIS

11

Blocked outlet contigency

12

Design pressure of HP Separator V-401

4600 kPag

13

Set pressure of PSV (= PZAHH of HP Separator x 10%):

4240 kPag

14

Fire contigency

  16

1.

. Input nput proc proces esss dat data: a:

17

-

Operating conditions o

Op. Pressure: 1120-3500 kPag

18 19

-

20

Op.Temperature: 4-38 C

o

Ambient temperature: 4 - 38 C

HP Separator geometry Assu Assum me th that HP Se Sepa para rato torr con conta tain inss lliq iqu uid with with HLS HLSD of of Ves Vesse sell V V-4 -40 01 (re (refe ferr tto o Pro Proce cess ss Equi uip pment ent siz sizin ing g cal calcu cula lati tion onre rep port rt))

21

-

22

Tota tall aast stim imat ated ed HP Sepa Separa rato torr vol volu ume refe referr to to P Pro roce cess ss Equip quipm ment ent ssiz izin ing g ccal alcu cula lati tio onrep nrepor ortt 214.708

Liquid volume:

23

-

m3

Vapor volume:

41.773

m3

PSV-2060-1 data

24

Set pressure:

4240

kPag

Accumulation: 21% of set pressure

25

Relieving pressure:

5130

kPag

Back pressure:

26

Coefficient of discharge K d: d:

27

2.

kPa (preliminary estimation)

0.975

Vapo Vaporr reli relief ef lo loa ad

28 29

70

In order to define gas relieving rate through PSV under fire exposure, below scenarios to Boiling liquid in case Max Gas (Case 07) 3.

Late Latent nt h hea eatt dete determ rmin inat atio ion n

30

-

Relieving temperature is simulated by HYSYS

31

-

Vapor and liquid volumetric flowrates are adjusted to their actual volume occupied in HP Separator including 10% of piping inventory.

32

-

Total heat input (Q) from fire will be transfered to fluid, heat accumulated by vessel metal is not considered. Input heat (Q) is used mainly to increase the fluid temperature (Sensible Heat Q s) and partly to vaporise the liquid (Latent Heat of Vaporization H)

33 34

-

35 36

Relief liquid is flashed fractionally at 1%, 2%, 5% to determine its respective latent heat. Repetition is interupted once the latent heat tends increasing and the flashing vapour will be relieving flowrate as required.

4.

Line ine ssiz izin ing g ccri rite teri ria a

37

Lin Linee si size ze will will be veri verifie fied d based based on g gas as flow flow reli relieve eved d by rea reall orifc orifcee area area (rated (rated flo flow) w) an and d PSV PSV tailp tailpipe ipe back back press pressure ure iiss at atmos mosph phere. ere.

38

-

39

PSV upstream line: v < 20 m/s

 

∆P

< 0.03 x PSV set pressure

∆P

< 0.1 x PSV set pressure

41

Mach number < 0.75

 

 

Project Unit 135355

Revision Date Originator  Checked by Approved by

CALCULATION NOTE PRESSURE RELIEF SIZING

Code

Discipline

Type

01

REP

0

1

Serial Number

Rev.

009

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2

R  e   v  .

1 2

DETAILED CALCULATION PSV-402

3

1. PSV Relief Load

4

5

Relieving pressure =

46000

kPag

Max Gas production (Case 07)

6

7

8

Latent heat of vaporization is determined by fractionally flashing liquid portion, Mass Heat of Vaporization and detailed

9

calculation are as table below. Refer HYSYS MODEL showing this flashing arrangement in page 7 of 7. 1%

2%

C

190.0

190.0

Input Heat Heat - Q

kJ/h

6922243.9

14590780.4

Sensible Heat - Qs Mass vaporisation

kJ/h kg/h

6513354.3 1325.526

13476595.2 2651.052

15

Molecular weight

-

40.14

43.61

16

Latent heat of vaporization

kJ/kg

308.474

420.3

kCal/kg

73.7

100.4

Cal.

601.09

Selected

Q

10

Vaporised fraction

11

Relieving temperature

12

o

5%

13

14

17

2

18

Orifice size (mm )

19

20

Gas flowrate to be relieved

kg/hr 

24506.1

21

Rated flow @ 1.21*Pset

kg/h

33851

MMscfd

16.93

22

23

24

24506

From above calculation, the orifice size J with the rated flow of

kg/h will be selected for PSV-402

25

26

2. PSV Inlet and Outlet Line Size

27

The gas flow released by real orifice area (rated flow) is employed to verify the PSV inlet / outlet line size corresponde correspondence nce

28

Rated flow (Case #1, 1% of vaporization)

33,851.4   kg/h

29

30

31

32

33

34

35 36 37 38 39 40 41 42 43

i) PSV Inlet Line

Size (inch) Velocity (m/s) ∆ P/ Pset 4

17.79

1.07

Check  Yes

ii) PSV Outlet line

Size (inch) Mach Number ∆P/ Pset 6

0.028

2.02

Check  Yes

Page

(See detail in note of page 5 of 7)

 

Project Unit 135355

Revision Date Originator  Checked by Approved by

CALCULATION NOTE PRESSURE RELIEF SIZING

Code Discipline

Type

01

REP

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Serial Number

Rev.

009

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2

Page

1 2

DETAILED CALCULATION PSV-402

3

HP SEPARATOR INVENTORY CALCULATION

4 5

Dime Dimensi nsion on o off HP Se Sepa para rato torr ar aree give given n in the the dat datas ashe heet et::

6 7

Ass Assume ume li liqui quid d volume volume contain containss HP Separa Separator tor es estim timatl atly y equals equals fluid fluid volume volume from from bot bottom tom to HL HLSD. SD.

8

Therefore, the liquid level shall be

2.90

m

(refer to Process Equipment sizing calculation report)

9 10

With the dimension of HP Separator as below:

11 12

Length T/T:

12.000

m

(refer to Process Equipment sizing calculation repor  

13

ID:

4.500

m

(refer to Process Equipment sizing calculation repor  

14 15 16

And the volumes and area of HP Separator is flowing:

17 18

Total liquid volume

144.380

m3

(refer to Process Equipment sizing calculation report)

19

Total volume

214.708

m3

(refer to Process Equipment sizing calculation report)

20

Total wetted area

114.014

m2

21

% liquid volume

67.2

%

22 23

Heat input (from equation 6 of API 521)

2099.854

kW

24 25 26

Q is the the total total heat heat absor absorptio ption n (input (input)) to the wetted wetted surf surface ace,, express expressed ed in W ((Btu Btu/h) /h);;

27

C1 = 43200

28

F is an en envi viro ronm nmeent fac acto torr = 1

29

Aws Aws is th thee to tota tall wett wetted ed surf surfac ace, e, =

30 31 32 33 34 35 36 37 38 39 40

114.014

m2

R  e   v  .

 

Project Unit 135355

Code Discipline

Type

01

REP

0

1

Revision Date Originator  Checked by Approved by

CALCULATION NOTE PRESSURE RELIEF SIZING

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Rev.

009

00

2

R  e   v  .

1 2

DETAILED CALCULATION PSV-402

3

PRESSURE RELIEF VALVE CALCULATION

4 5

Latent heat 2099.9

Heat input  

6

1%

kW

7,559,472.93 kJ/hr

 

Max Gas production (Case 07) 30 8. 8.5

2%

5%

420.3

0.0

7 8 9

INPUT DATA

10

ENGLISH UNIT

11

Cas asee (% vola volati tile le mas mas ss))

12

Latent heat of vaporization

13

Design Mass flow

W

1%

2%

5%

308.5

420.28

0.00

24506.1

17986.7

4600

4600

4600

4240

4240

1%

2%

5%

kJ/kg

#DIV/0! kg/hr 

54027

39653.9 ###### lb/hr 

kPag

681.87

681.87

681.87  psia

4240

kPag

629.66

629.66

629.66  psia

14 15

Ves. Design pres.

16 17

Set pressure

18

Constant Back Pres.

70.0

70.0

300

kPa

10.15

10.15

43.51  psia

19

Built-up Back. Pres.

0

0

0

kPa

0.00

0.00

0.00  psia

20

Total Back pressure

70

70

300

kPa

10.15

10.15

43.51  psia

0.21

0.21

0.21

0.21

0.21

0.21

5130.4

5130.4

758.80

758.80

758.80  psia

833.7

833.7

491.7 R 

Ps

P2

21 22

Allow. Over pres.

23

Max relief pressure

P1

5130.4 kPag o

24

Temp. Tem p. @ max max rel relief ief pres pres.. T1

190.0

190.0

0

25

Molecular Weight

MW

40.14

43.61

29.297

40.14

43.6147 29.297

26

Z factor

Z

0.8274

0.796

0.7107

0.8274

0.79643 0.7107

27

k (Cp/Cp-R)

k  

1.084

1.074

1.0863

1.0835

1.07435 1.0863

28

Coef. Of discharge

Kd

0.975

0.975

0.975

0.975

0.975

0.975

29

Back pres. Factor

Kb

1

1

1

1

1

1

30

Comb. Cor. Factor

Kc

1

1

1

1

1

1

31

C

DETAIL CALCULATION RESULTS

32 33

Critical pressure

34

Downstream flow regime

35

Coefficient

C

324.9

323.923

325.243

36

Coef. Coef. O Off subc subcriti ritical cal flo flow w F

0.036

0.035

0.119

37

Area calculated

38

Re Req. q. eff. eff. disc discha harg rgee aare reaa

39

Selected area

40

Recommended orifice

41

Recommended area

446.30

Pc

CRITICAL

A

 

0.932

44

Ra Rate ted d relie relievin ving g cap capac acit ity y

445.85  psia

CRITICAL RITICA

0.646

#DIV/0! in2

J 1.287 .

43

447.78

Q

-

-

-

-

74629.46 33851

45 Note: (*) PSV size will be confirmed by Vendor

-

in2

-

lb/hr 

-

kg/hr

Page

=

16.93 MMSCFD

 

Project Unit

Code

135355

Discipline

Type

01

REP

0

1

Revision Date Originator  Checked by Approved by

CALCULATION NOTE PRESSURE RELIEF SIZING

Serial Number

Rev.

009

00

2

Page R  e   v  .

1 2

DETAILED CALCULATION PSV-402

3 4

PSV INLET / OUTLET LINE CHECKING Max Gas production (Case 07)

5 6 7

Inlet

Outlet

FROM

HP Separator 

PSV

TO

PSV

FLARE

Mass flow

qm

9

Molecular Weight

MW

kg/h

33851

33851

40.14

40.14

0

C

190.00

173.94

11

0

R 

833.67

804.76

12

0

K 

463.15

447.09

Temperature

13

Compressibility average

Z

0.827

0.993

14

Secific heat ratio

k = Cp/Cv

1.224

1.104

15

Act. Volume flow

Q

m /h

3

526.04

18166.36

16

Viscosity

μ

cP

0.0175

0.0139

17

Out le let vapor density

ρ

kg/m3

64.351

1.863

18

Pressure Relief

Prelief

kPaa

5231.7

5231.7

D

mm

100

100

40S

40

   

19

II. PIPE & F FITTINGS ITTINGS DATA

20

  Pipe DN

21

Pipe Schedule

22

Pipe I.D.

23

Roughness

 

d

mm

102.26

154.055

е

mm

0.05

0.05

m

10.12

2.75

17.79

270.72

20369.9

 136,570.39

6.70E+06

5.6E+06

311.68

318.52

292.07

145.84

0.017

0.015

0.056 

0.028

24

Pipe length

L

25

 V  Veelocity

V

m/s 2

26

 Momentum

27

Reynolds number

28

Sonic velocity

29

Critical Pressure at (Mach =1) Pc

30

Friction factor  

ρV 

 

kg/m.s

2

Re  

σ

kPaa

f  m

31

 M  Ma ach Number

32

Fittings

M   Qty

Qty

Full bore 40 mm and smaller

65

D

0

0

Full bore 50 mm and larger

45

D

1

1

Flow straight through

20

D

0

0

Flow through side outlet

65

D

1

0

90°, R= 1 ½ D

20

D

0

2

45°, R= 1 ½ D

16

D

2

0

Reducer

0.17

m

1

0

56

Expander

0.12

57

Equivalent Length of Fittings, Reducer, Expander, Pipe

33

  Ball Valve

34 44 45 46 47 55

58

  Tee-equal   Elbow

m

0

1

m

24.49

11.37

III. CALCULATIONS

59

Pipe Pressure drop

kPa/1m

1.670

6.826

60

P iip pe an and Fi Fi tt ttings P Prressur e dr op op

kPa

40.9

77.6

61

Other ∆P

kPa

0.000

0.000

62

Design Margin

20%

8.18

15.52

.

.

4600

4600

ota 64

a

ressur ressuree rop rop

kPag

PSV Set Pressure

65

as % of Set Pressure   Pressure Drop as

66

 Allowable Pressure Pressure Drop as API 521 (%) (%)

69

Inlet pipe size of PSV: DN 100 Outlet pipe size of PSV: DN 150

I. GENERAL

8

10

Conclusion:

%

1.07 

2.0

3.00

10.00

 

Project Unit 135355

CALCULATION NOTE

Revision Date Originator 

PRESSURE RELIEF SIZING

Checked by Approved by

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 54 55 56 57

PSV-402 SIMULATION MODEL

Code

Serial Number

Rev. 00

Discipline 01

Type REP

009

0

1

2

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